Traditional uses and potential health benefits of Amorphophallus konjac K. Koch ex N.E.Br.

Journal of Ethnopharmacology 128 (2010) 268–278 Contents lists available at ScienceDirect Journal of Ethnopharmacology journa l homepage: www.e lsev ier .com/ locate / je thpharm Review Traditional uses and potential health benefits of Amorphophallus konjac K. Koch ex N.E.Br. Melinda a School of App b HMREC, Facu a r t i c l Article history: Received 5 October 2009 Received in revised form 6 January 2010 Accepted 6 January 2010 Available online 15 January 2010 Keywords: Amorphophall Konjac Traditional Ch Konjac glucom Dietary supple Amorphophallus konjac (konjac) has long been used in China, Japan and South East Asia as a food source and as a traditional medicine. Flour extracted from the corm of this species is used in Far Eastern cuisine to make noodles, tofu and snacks. In traditional Chinese medicine (TCM), a gel prepared from the flour has been used for detoxification, tumour-suppression, blood stasis alleviation and phlegm liquefaction; and for more than 2000 years has been consumed by the indigenous people of China for the treatment Contents 1. Introd 2. Tradit 3. Cultiv 4. The m 5. Locali 6. Comm Abbreviation Administratio KGMO, konjac glucomannan ∗ Correspon E-mail add 0378-8741/$ – doi:10.1016/j. us konjac inese medicine annan ment of asthma, cough, hernia, breast pain, burns as well as haematological and skin disorders. Over the past two decades, purified konjac flour, commonly known as konjac glucomannan (KGM) has been introduced on a relatively small scale into the United States and Europe, both as a food additive and a dietary supplement. The latter is available in capsule form or as a drink mix and in food products. Clinical studies have demonstrated that supplementing the diet with KGM significantly lowers plasma cholesterol, improves carbohydrate metabolism, bowel movement and colonic ecology. Standards for the classification of both konjac flour and KGM have been established by the Chinese Ministry of Agriculture, the European Commission and the U.S. Food Chemicals Codex. However, to date, there is no worldwide agreed regulatory standard for konjac flour or KGM. This highlights the need for harmonization of konjac commercial standards to assess and ensure the quality of existing and future KGM products. Despite the widespread consumption of konjac derived products in East and South East Asia, there has been limited research on the biology, processing and cultivation of this species in theWest. Most studies performed outside Asia have focussed on the structural characterisation and physicochemical properties of KGM. Therefore, the objective of this monograph is to review the literature covering the ethnic uses, botany and cultivation of konjac corms, together with the health benefits of KGM with the associated require- ments for quality control. Possible directions for future research and development and standardisation of production and classification of this versatile natural product will be discussed. © 2010 Elsevier Ireland Ltd. All rights reserved. uction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269 ional and contemporary uses of konjac corms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269 ation of Amorphophallus konjac . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270 olecular composition of Amorphophallus corm tissue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270 sation, structure and physicochemical properties of KGM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270 ercial production and processing of KGM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271 s: ApoB, apolipoprotein B; BioMatNet, biological materials for non-food products; cp, centipoise; EFSA, European Food Safety Authority; FDA, Food and Drug n; FBG, fasting blood glucose; FCC, Food Chemicals Codex; HCA, hydroxycitrate acid; HDL-C, high-density lipoprotein cholesterol; KGM, konjac glucomannan; glucomannan oligosaccharides; LDL-C, low-density lipoprotein cholesterol; MRS, DeRogosa and Sharpe; SCFA, short-chain fatty acid; PKGM, pulverised konjac ; TC, total cholesterol; TCM, traditional Chinesemedicine; USDA, U.S. Department of Agriculture;WFS,World of Food Science;WMD,weightedmean difference. ding author. Tel.: +61 2 4620 3837/9114 4185. resses: [email protected], [email protected] (K. Chan). see front matter © 2010 Elsevier Ireland Ltd. All rights reserved. jep.2010.01.021 Chuaa, Timothy C. Baldwina, Trevor J. Hockinga, Kelvin Chana,b,∗ lied Sciences, University of Wolverhampton, Wulfruna Street, Wolverhampton WV11LY, United Kingdom lty of Pharmacy, The University of Sydney, NSW2006, and CompleMED, College of Health & Science, University of western Sydney, NSW2560; Sydney, Australia e i n f o a b s t r a c t M. Chua et al. / Journal of Ethnopharmacology 128 (2010) 268–278 269 7. Potential health benefits of KGM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271 7.1. Anti-obesity activity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271 7.2. Anti-hyperglycemic and hypercholesterolemia activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272 7.3. Laxative effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273 7.4. . . . . . 7.5. . . . . . 8. Qualit . . . . . . 9. Discu . . . . . . Ackno . . . . . Refer . . . . . . 1. Introdu Plants o in tropical tional Chin an undergr sected umb mainly in t (Hettersche i.e. A. albus Engl. & Geh H. Li & C.L. Li and A. yu der and for utilised, is rivieri or ko “konnyaku” for thousan of whole co West are in fibre extrac mannan (K of dietary s the botany, reference to 2. Traditio The Chin first describ ica” during to the ancie is a toxic, p tionally, cor sliced, drie sumed in th ash. In TCM have partia (serotonin tion, tumou blood) allev al., 2001). F the treatme as haemato consumed snacks (Bro al., 1993), o with meat derived fro insect repel Southern Ch During t as a valuabl Korea ugh mura iu, 2 apan gelat aki) a e Asi mpo deve ted i uce rther dolo (Ta rodu ch of ial fo ble o t ma es (M iscou ty. A d pa ferm as re food for i obes anso 9, 2 tenti t al., an im ted. uniq yed i tic an ed a (FD ssed men 5 ag Prebiotic activity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Anti-inflammatory activity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . y and safety of KGM products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ssion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . wledgement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ction f the genus Amorphophallus have a long history of use and subtropical Asia as a food source and as a tradi- ese medicine (TCM). They are perennial plants with ound stem in the form of a corm and a highly dis- rella-shaped leaf blade. Of the 170 species distributed he tropics from West Africa eastward into Polynesia id and Ittenbach, 1996), nine Amorphophallus species, P.Y. Liu & J.F. Chen, A. corrugatus N.E.Br., A. kachinensis rm., A. konjacK. Koch exN.E.Br., A. krausei Engl., A. nanus Long, A. paeoniifolius (Dennst.) Nicolson, A. yuloensis H. nnanensis Engl. have been used as food, medicine, fod- wine production (Liu, 2004). One of the most widely Amorphophallus konjac K. Koch ex N.E.Br. (synonym A. njac; Chinese: , “ju ruo”; Japanese: , ; Korean: , “gonyak”),whichhasbeenused inChina ds of years (Fig. 1). Despite the historical use in China rm extracts as a TCM, the current usage of konjac in the the food and nutraceutical industries; where soluble ted from the corms, commonly known as konjac gluco- GM) is used as a food additive and in the development upplements or nutraceuticals. This review will include cultivation and uses of konjac corms, with particular the properties and uses of KGM. nal and contemporary uses of konjac corms ese were the first to study and utilise konjac and it was ed as a medicinal herb in the “Shen Nong Materia Med- the Western Han Dynasty (206 BC–08 AD). According nt Chinese pharmacopoeia, “Ben Cao Gang Mu”, konjac ungent and cold-natured herb (Xu et al., 2001). Tradi- ms (underground storage organs) are washed, peeled, d and ground to produce konjac flour which is con- e form of cake (or gel) after boiling the flour with plant , the therapeutic effects of extracts from konjac corms lly been ascribed to its pungent and toxic principles and its derivatives) with the functions of detoxifica- r-suppression, blood stasis (slowing or pooling of the iation and phlegm liquefaction (Niwa et al., 2000; Xu et or more than 2000 years, konjac gel has been used for nt of asthma, cough, hernia, breast pain, burns as well logical and skin disorders. Konjac flour has also been North lic thro and sa stuff (L In J into a (shirat Outsid tiful co 2002). The origina to prod was fu metho as KGM food p Mu potent as solu of plan enzym most v capaci vary an and is KGM h and in touted 2007), and Sw al., 199 The po Chen e and as sugges The emplo cosme approv tration also pa Depart an E42 as a functional food in the form of noodles, tofu and wn, 2000; Douglas et al., 2005; Long, 1998; Wootton et r as konjac curd, which is tasteless and usually braised in traditional cuisines. In addition to the use of flour m the corm, the leaves of konjac are used as a natural lent and as animal fodder by the indigenous people in ina (Long, 1998). he sixth century A.D. konjac was introduced into Japan e medicine by a religious delegation sent by the King of ity (EFSA) ( delivery sy et al., 2008 disposable These re cations hav prompting erties and im potential. In . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277 . Konjacwas graduallymadeknown to the general pub- the rulingclass in Japan (monks, governmentauthorities i) and eventually became popular as a vegetarian food- 004). ese cuisine, konjac flour is poundedwith lime andwater inous grey cake, a key ingredient in Japanese noodles nd cuisines such as sukiyaki and gyudon (Brown, 2000). a, konjac is also grown as an ornamental due to its beau- und foliage and marbled petioles (Follett and Douglas, lopment of commercial konjac processing technologies n Japan. Nakajima (1745–1826) developed a technique konjac flour by pulverising dried chips of the corm. This improved byMashiko (1745–1854)who developed the gy to produce purified konjac flour, commonly known kigami, 2000). Originally this purified flour was used in ction and was later also used as a food additive. the recent interest in the use of konjac stems from its r use as a dietary fibre. The term dietary fibre, classified r insoluble, is described as the endogenous component terial in the diet that is resistant to human digestive cCleary, 2003). KGM is water soluble and is one of the s dietary fibres known, due to its high water-absorbing s �-1,4 linkages of KGM cannot be hydrolysed by sali- ncreatic amylase, KGMpasses into the colon unchanged ented by colonic bacteria (Keithley and Swanson, 2005). cently been marketed in capsule form, as a drink mix products (Brown, 2000; Talbott, 2003) and has been ts potential in the treatment of obesity (Kraemer et al., ity-related dyslipidemia (Gallaher et al., 2000; Keithley n, 2005; Vasques et al., 2008) and diabetes (Vuksan et 000, 2001) by promotion of satiety (Sood et al., 2008). al use of KGM as a prebiotic (Al-Ghazzewi et al., 2007; 2005, 2006, 2008; Elamir et al., 2008;Wang et al., 2008) munomodulator (Onishi et al., 2007a,b) has also been ue rheological and gelling properties of KGMarewidely n emulsifier and stabiliser products for the food, drinks, d pharmaceutical industries. Since 1994, KGMhas been s a food additive by the U.S. Food and Drug Adminis- A) (Takigami, 2000; Zhang et al., 2005). In 1996 it was as a binder in meat and poultry products by the U.S. t of Agriculture (USDA). In Europe, KGM has been given reement number by the European Food Safety Author- FSA, 2007). KGM has also been used in controlled drug stems (Alonso-Sande et al., 2009; Alvarez-Mancenido ) and in the production of absorbent materials such as nappies and sanitary towels (Kok et al., 2009). centdevelopments inboth industrial andmedical appli- e proved pivotal to the increasing demand for KGM, studies to fully characterise its physicochemical prop- prove konjac agronomy in order to increase itsmarket addition, little is known regarding the mechanism of 270 M. Chua et al. / Journal of Ethnopharmacology 128 (2010) 268–278 action(s) of other active ingredient(s) present in the corm which was once widely used in TCM in Southern China. 3. Cultivation of Amorphophallus konjac Amorpho in South E distributed nam(Brown (Brown, 200 “Perenn ing rhizo leaf with dark gre across, b to 6 cmw broadly long and face rou maroon- long, em Since ko shady envir rich soils o Amorphoph ranging bet of 20–25 ◦C Southern C tall grain c to protect t of Japan (G overwinter (Brown, 200 the main di gated prior such soil-bo The cont oping corm just before modern Jap harvesting the winter Follett and corms may next season vested for d after one ye at ∼2kg for konjac need ketable cro corm. China is vation of ∼ factories de goods (En, 2 phophallus, this provinc konjac flour an agronom domestic an ing planting been implem poverty (W Japan is konjac are g Table 1 Carbohydrate content (% of total dry weight) in the corm of Amorphophallus species from various sources (Liu, 2004). Species Location Glucomannan Starch Soluble sugar jac s ensis inens sei niifol in Ch ter t ai an nstit mi, side Wes t was tion urpo thro tNet l pra ects es (D mol man n, 10 nium , pho 5–14 % (w poni c com iamin y cis- nin h 000) andg s cult r ma alisation, structure and physicochemical properties tissue structure of 2 year old corms of A. konjac have been by Takigami and colleagues, who reported that KGM gran- cumulate in egg-shaped idioblasts within the parenchyma at the size and number of these idioblasts increases with e from the epidermis, reaching ∼650�m in diameter at the l region of the corm (Takigami et al., 1997).Within the corms, oxalate is deposited in needle-shaped raphide crystals mi et al., 1997) and inmulti-crystal druses (cluster crystals) id et al., 2008) which can be found in the KGM idioblasts and rounding parenchyma (Takigami et al., 1997). phallus konjac K. Koch ex N.E.Br. (Araceae) originates ast Asia (Hetterscheid and Ittenbach, 1996) and is throughout Southern and South EasternChina andViet- , 2000). Abotanical descriptionof konjac is givenbelow 0). ial with globose tuber to 30 cm in diameter, produc- matous offsets to 50 cm long and 3 cm thick. Solitary smooth dull pink-white petiole to 1m long, marbled en and dottedwhite, with highly dissected blade to 2m earing pointed elliptic leaflets 3 to 10 cm long and 2 ide. Peduncle to 1.1m long, coloured as petiole. Erect, triangular, funnel-shaped, fluted spathe, 10 to 60 cm 10 to 55 cm across, with wavy margins; outer sur- gh, dull brown-green with black-green spots; inside brown. Spadix maroon, narrowly conic, 15 cm to 1.1m itting foetid odour for several days.” njac is indigenous to tropical rain forest, it growswell in onments (Mayo et al., 1997)with free-draining, humus- f pH 6.5–7.5 (Brown, 2000). It is one of the hardiest allus species and can grow in seasonal temperatures ween 5 and 43 ◦C with an optimum temperature range (Brown, 2000; Hetterscheid and Ittenbach, 1996). In hina, konjac has been traditionally intercropped with rops such as maize and sorghum (Long et al., 2003), he plant from direct sunlight. In mountainous regions unma Prefecture) where konjac is not truly hardy, it is ed by mulching heavily with grain straw or wild herbs 0). The bacterial soft rot erwinia (Erwinia carotovora) is sease problem with this crop. In Japan, soils are fumi- to planting in conjunction with crop rotation to control rne diseases (Follett and Douglas, 2002). ent of KGM, the storage carbohydratewithin the devel- , changes throughout the growing season and is highest the foliage dies off, prior to dormancy (Brown, 2000). In anese practice (“Uedama”), older corms are sold after and the remainder are kept frost free (5–7 ◦C) during months in aerated storage rooms (Douglas et al., 2006; Douglas, 2002; Kurihara, 1979). In Southern China, be left all year in the field to continue growing to the (Brown, 2000; Kurihara, 1979) and are usually har- omestic use when they weigh 200g, which may occur ar of growth, or are left for three years and harvested commercial processing (Brown, 2000). Whether or not s to be grown for one or more years to achieve a mar- p is dependent on the size and quality of the planted the main producer of konjac with an area under culti- 200km2 (Xu et al., 2001) and has approximately 400 voted to the production of konjac flour and related 008). Yunnan is the ‘richest’ province in terms of Amor- with 15 of the 22 indigenous species being native to e (Long et al., 2003). Due to the increasing demand for , konjac is now regarded by the Chinese government as ically important crop which has great potential in both d international markets (WFS, 2003). Projects involv- konjac inmountainous regions of Southern China have ented by provincial governments to help combat rural FS, 2003). the second largest producer of konjac. Five cultivars of rown namely: Zairai (originated in Japan), Shina (orig- A. kon A. albu A. yulo A. kach A. krau A. paeo inated The lat of Zair vars co (Takiga Out crop in projec produc food p Europe (BioMa cultura the eff densiti 4. The tissue Dor manna (alumi ganese zinc), 3.4–5.3 and sa Organi and th namel seroto et al., 2 origin specie as thei 5. Loc of KGM The studied ules ac and th distanc centra calcium (Takiga (Prych the sur Sichuan 58.8 12.3 2.9 Chongqing 12.9 2.7 Guizhou 58.3 12.7 2.7 Yunnan 54.4 16.2 3.8 Hubei 54.6 17.3 3.2 Guangxi 55.1 14.1 3.4 Jiangxi 52.2 19.8 2.9 Fujian 52.1 20.1 3.5 Sichuan 59.3 11.5 1.5 Yunnan 33.7 38.8 5.5 i Yunnan 39.8 46.1 8.3 Yunnan 28.5 21.0 7.6 ius India – 35–70 – ina), Haruna-kuro, Akagi-ohdama and Miyogi-yutaka. hree are hybrids resulting from the cross-fertilization d Shina. The Haruna-kuro and Akagi-ohdama culti- ute ∼90% of the total Japanese konjac corm production 2000). Asia, konjac is being investigated as a potential new tern Europe and in New Zealand. An E.U. collaboration carried out in France to develop methodology for the , processing and utilisation of konjac for food and non- ses, to establish an integrated KGM production chain in ugh increased local konjac availability and processing , 2000). In New Zealand, studies to devise good agri- ctice (GAP) for cultivation of the crop have included of shade, fertilisers (Douglas et al., 2005) and planting ouglas et al., 2006) on corm yield. ecular composition of Amorphophallus corm t corms of A. konjac contain 49–60% (w/w) gluco- –30% (w/w) starch, 2.6–7% (w/w) inorganic elements , calcium, chromium, cobalt, iron, magnesium, man- sphorus, potassium, selenium, silicon, sodium, tin and % (w/w) crude protein, 3–5% (w/w) soluble sugars, /w) ash and a small amount of alkaloids (trigonelline) n at their stem base (Li et al., 2005; USDA, 2004). pounds such as �-carotene, choline, niacin, riboflavin e (USDA, 2004) as well as serotonin and its derivatives N-(p-coumaroyl) serotonin and trans-N-(p-coumaroyl) ave also been identified in the fresh corm tissue (Niwa . The composition of mature corms varies with species, rowingconditions (Table1).Of thenineAmorphophallus ivated inChina,A. konjac andA. albushaveglucomannan in storage carbohydrate (Liu, 2004). M. Chua et al. / Journal of Ethnopharmacology 128 (2010) 268–278 271 Fig. 1. Amorphophallus konjac. Two years old konjac corm (A); konjac plant (B); konjac inflorescence (C). KGM (Fi mannose r �-1,6-gluco approximat and glucose along the K are located 1992) The m varying wit (Sugiyama and forms and 7.0 (Va and mecha tionmight d (�-mannan alkali to KG 6. Comme Differen ent purities used in nut ally, farmer slices of kon cially as fol washed to r sliced into c emits sulph konjac chip konjac flou onjac s star e cr itatio l eth s D-g tion utra y fum flour . The ated ltura ation d kon are 5) d vity ased flou to i entia ti-ob view e of 3 l as g. 2) is composed of �-1,4-linked D-glucose and D- esidues as the main chain, with branches through syl units. The degree of branching is estimated at ely 3 for every 32 sugar units. It consists of mannose units in a molar ratio of 1.6:1 and the acetyl groups GM backbone which contribute to solubility properties every 9 to 19 sugar units at the C-6 (Nishinari et al., olecular weight of KGM ranges from 200 to 2000kDa, h cultivars, origin, processing method and storage time et al., 1972). KGM is dispersible in hot or cold water a highly viscous solution in a pH range between 4.0 nderbeek et al., 2007). Solubility is increased by heat nical agitation (FCC, 1996). The viscosity of KGM solu- ecrease upon storage, possibly by bacterial or enzymic se) hydrolysis (Nishinari et al., 1992). Addition of mild Msolution results in the formation of thermo-stable gel. rcial production and processing of KGM t commercial applications of konjac flour require differ- of flour, with the highest glucomannan content being raceutical applications (Fang andWu, 2004). Tradition- s prepared konjac flour by air drying then pounding jac corm. Currently, konjac flour is produced commer- lows. Before processing, the external corm surfaces are emovedirt and soil (Fig. 3a). The cleaned corms are then hips (Fig. 3b.) followedbydrying in ahot air drier,which ur dioxide as a bleaching agent to prevent darkening of s. The dried chips are then pulverised to produce crude mon k such a from th precip severa such a extrac flour (n chips b crude cesses formul Agricu purific purifie in turn al. (200 bioacti (decre konjac leading 7. Pot 7.1. An A re ple siz as wel r which has a fish-like smell and an acrid taste. Com- Swanson, 2 Fig. 2. Chemical structure of KGM (Okimasu and flour (food grade) is produced by removing impurities ch, protein, cellulose and low molecular weight sugars ude pulverised flour, either bywind sifting or by alcohol n (Liu et al., 1998; Takigami, 2000). The latter involves anol washings to remove low molecular weight sugars lucose and D-fructose in the flour, followed by aqueous at room temperature (Liu et al., 1998). Purified konjac ceutical grade) is producedwithout bleaching the sliced igationwith sulphur dioxide and the resultant ‘organic ’ undergoes a series of extraction and purification pro- se are followed by product inspections before being into KGM supplements (Yunnan Fuyuan Jintianyuan l Development Company Ltd., 2008). The extraction and procedures are crucial as theymay affect the quality of jac flour in terms of physicochemical properties which related to the pharmacological activities of KGM. Li et emonstrated a significant improvement in anti-obesity ofmilled konjacflour compared tounmilled konjacflour grain size from 765.3 to 23.7�m). Small grain size of r is thought to increase the swelling velocity of KGM, ncreased anti-obesity activity. l health benefits of KGM esity activity of studies (seven clinical trials with an average sam- 9 participants) using KGM for the treatment of obesity studies of its mechanism(s) of action (Keithley and 005), concluded that KGM may possess properties that Kishida, 1982). 272 M. Chua et al. / Journal of Ethnopharmacology 128 (2010) 268–278 orm s promote w mal caloric of KGM for cephalic an slowed bow trointestina in the smal and insulin 2007). Kraemer body exerc with KGM lipid param interventio body mass (men, −2.3 (TC) (men, inclusion o improveme high-densit the authors containing leptin (by∼ an adipose regulates b et al., 2007) 7.2. Anti-hy The rheo important m plasma gluc betic indivi an alternati the viscosit xanthan at glycemia fo added, clos 12×10−1 cp KGM demo psyllium. In porating KG diabetics ha added to a compared t occasions. B consumptio culated as sed a strat f 42 dditi erabl GM t typ KGM pert a lo o-con reatm ults d du 5±1 tly b ignifi The sed b c blo ntati trol nceo at bo ) emp sions sam -carb ts wi l de 3.1% -C ra rum reatm Fig. 3. Washing of corms (A); dried c eight loss when used in conjunction with either a nor- or a hypocaloric diet. Thepossiblemechanismsof action weight loss are by promotion of satiety via induction of d gastric-phase signals, delayed gastric emptying and el transit time due to the increased viscosity of gas- l content, as well as reduced rate of food absorption l intestine leading to attenuated postprandial glucose surges (Keithley and Swanson, 2005; Kraemer et al., et al. (2007) studied the effects of adding a total- ise program to an eight week diet supplemented (3 g/day) on weight loss, body composition and blood eters in overweight men and woman. A dietary n with GM alone promoted reductions (P M. Chua et al. / Journal of Ethnopharmacology 128 (2010) 268–278 273 −15.99mg/dl), triglycerides (WMD: −11.08mg/dl), body weight (WMD: −0.79kg) and FBG (WMD: −7.44mg/dl), but not HDL-C or blood pressure. Studies have also been performed to assess whether a com- bination of greater hyp tion with K (2002), (21 2.4 g/day of chitosan (in ton of arthr of normal lipids were plementing (TC, 7%; LD ble fibres (overweigh supplemen would not the KGM, o In another KGM (10g/ (1.8 g/day) in mildly hy without (16 crossover s were signifi combinatio (3.60±0.16 (Yoshida et (2008) eva (HCA), a co Garcinia cam obese subje out dietary placebo gro given daily to their ma (−32.0±35 observed in of joint adm for statins, ically aime Although s ment for h treatment f intake (BMA 7.3. Laxativ Dietary fi constipatio shown to be 2007). The dietary fibr colonic pro of colonic tation as w 2006). Chen an (4.5 g/day; 1 seven slight blind, place (allowed su 1.5 to 3g/d plement wa frequency, wet stool weight and dry stool weight by 27% (from 7.7 to 9.8 times per week), 30.2% and 21.7%, respectively, in healthy adults with no gastrointestinal side effects being reported during the period of supplementation. In addition, increase in wet stool (per ntati .4 g), to-ol KGM frequ (3.7 8). B GMp and freq et al. ebiot n et to e ) pro GM ks 2 trast rfring larg lev h fib ith 5 ce the ringe ed by gut sign ther tenti dyin on D men owth than he n GMO pre s in e eff 6) a of su tudy ort c tudie ch K trati d clo actio tion icrob of KG how -bor et al sed f dicat KGM and cholesterol-lowering agents produce any ocholesterolemic effect compared to supplementa- GM alone. In a study conducted by Gallaher et al. ) overweight normocholesterolemic subjects were fed a supplement containing equal amounts of KGM and digestible aminopolysaccharide found in the exoskele- opods and certain fungi) for 28 days with maintenance dietary and activity pattern during the study. Serum measured during the initial (day 7) and final sup- period (after 28 days). Reduced serum cholesterol L-C, 10%) to a degree beyond that of most solu- in a population that was likely to be unresponsive t normocholesterolemic subjects) suggested that this t is a potent cholesterol lowering agent. However, it be possible to tell whether the effects were due to r chitosan, or a mixture of both as used in this study. study, Yoshida et al. (2006) investigated the effect of day) and a combined supplement with plant sterols on the lipid profile as well as cholesterol biosynthesis percholesterolemic subjects with (18 individuals) and individuals) type 2 diabetes through a randomized, tudy for 21 days. Overall plasma LDL-C concentrations cantly decreased after KGM (3.16±0.14mmol/l) and n treatments (2.95±0.16mmol/l) compared to control mmol/l) in non-diabetic and type 2 diabetic subjects al., 2006). In the most recent study, Vasques et al. luated the therapeutic efficacy of hydroxycitric acid mpetitive blocker of ATP-citrase-lyase extracted from bogia andKGM for the treatment of obesity. Fifty-eight cts, attending a double-blind randomized study with- restrictions were assigned to a treatment (n=26) or up (n=32) for a 12 week observation. Subjects were doses of HCA (2.4 g) plus KGM (1.5 g), or placebo prior in meals (3 times/day). A significant reduction in TC .1mg/dl) and LDL-C (−28.7±32.7mg/dl) levels were the treated group. In addition, the hypolipemic effect inistration was quantitatively similar to that reported a competitive inhibitor of HMG-CoA reductase specif- d at reducing LDL synthesis in the liver (BMA, 2005). tatins are currently considered the benchmark treat- yperlipidemia (Vasques et al., 2008), it is not a safe or patients at risk of liver disease andwith ahigh alcohol , 2005). e effect bre has a significant role to play in the management of nandanaverage intakeof about18–27g/dayoffibrehas effective in treating constipation (Mann and Truswell, mechanism(s) responsible for the laxative effects of es include the increase of colonic content leading to pulsion which promotes defecation; the stimulation motility by fibres and end products of fibre fermen- ell as an increase in bowel movement (Chen et al., d colleagues examined the effects of KGM supplements .5 g/meal) in both eight healthy (Chen et al., 2006) and ly constipated adults (Chen et al., 2008) through single- bo-controlled studies, with 7 days of adaptation period bjects to adapt to KGM supplement progressively from ay) followed by 21 days KGM treatment. KGM sup- s shown to significantly increase the mean defecation weight pleme (4.8–5 isomal adults, cation weight al., 200 1.5 g K dosage cation (Chen 7.4. Pr Che studies (KGMO mice. K at wee By con iumpe caused and 5% at eac diet w enhan C. perf report on the able to In ano the po by stu grown supple the gr larger over, t with K inulin. The human ine th al., 200 stools each s and sh both s in whi concen reduce to the menta anti-m erties study s of food Elamir decrea also in place. gram of fibre consumed) was 12.7 g during KGM sup- on which is greater than reported for wheat bran fibre oat bran fibre (3.4–4.5 g), oligofructose (2.0–3.4 g) and igosaccharide (3.3 g) (Chen et al., 2006). For constipated supplement significantly increased the weekly defe- ency by 30% (from 4.1 to 5.3 per week) and faecal dry g/day) with reduced severity of stomach wind (Chen et ased on these two studies, the authors concluded that owder permeal could be an optimum supplementation that the ability of KGM supplements to promote defe- uency results primarily from the increased stool bulk , 2006, 2008). ic activity al. (2005) conducted time-course and dose-dependent xamine the effects of KGM and KGM oligosaccharides duced by acid hydrolysis on caecal microflora in Balb/C and KGMO significantly increased bifidobacteria counts and 4, respectively, compared with cellulose (control). , KGMandKGMOsignificantly decreased caecalClostrid- ens only atweek 4. In the dose-dependent study, KGMO er increases in faecal total anaerobe counts at the 2.5% els compared with KGM, and it was more bifidogenic re level. These data suggest that supplementing the % (w/w) KGM or KGMO for 4 weeks is sufficient to population ofBifidobacteria, associatedwith decreased ns and Escherichia coli. Similar observations have been Elamir et al. (2008) in a study on the effects of KGMO microflora of mice. They reported that the KGMO was ificantly reduce faecal C. perfringens and E. coli counts. study, Al-Ghazzewi et al. (2007) further investigated al use of KGMO (derived enzymatically) as a prebiotic g the growth profiles of lactobacilli and bifidobacteria e Man, Rogosa and Sharpe (MRS) media or in UHT milk ted with the oligosaccharides. The KGMO stimulated of all strains and the colony sizes were significantly those grown on pectin or xylan oligosaccharides. More- umbers of colony forming units in milk supplemented were significantly higher than those supplementing biotic effect of KGM has also been demonstrated in studies performed by Chen and colleagues to exam- ects of KGM supplements in both healthy (Chen et nd slightly constipated adults (Chen et al., 2008). The bjects from both the placebo and KGM treatments of were collected to determine the faecal microflora, pH hain fatty acid (SCFA) concentration. The findings in s were in agreement with the observations in mice, GM supplementation significantly increased the faecal ons of bifidobacteria and lactobacilli, associated with stridia to total faecal bacteria. This can be either due n of Bifidobacteria through the increase in acidic fer- products (mainly acetate and lactose) and secretion of ial substances, ormight due to the anti-microbial prop- M. The latter has been demonstrated by an in vitro ing that KGM and KGMhydrolysate prevent the growth ne C. perfringens and E. coli (Al-Ghazzewi et al., 2007; ., 2008). In addition, increased SCFA concentration and aecal pH observed in treated subjects for both studies ed that thepromotionof colonic fermentationhad taken 274 M. Chua et al. / Journal of Ethnopharmacology 128 (2010) 268–278 7.5. Anti-inflammatory activity In addition to the documented therapeutic effects of KGM as previously therapeutic such as atop (2004) fed f of atopic d highly puri and re-gran developme suppressed down regul skin inflam In a late PKGM on s responses i taining PKG as clinical to these au dent from 6 dose-depen feeding sign hyperkerato tion, cutane TNF- were cise mecha PKGM and investigated 8. Quality The lack medicinal p herbalmed There are s herbal prod as well as d active chem addition, m dling andm regulatory facturing an 1998) will a value of the For regu distinction 2001). Belo “Konjac the kon unpurifi Amorph the wat comann D-gluco 4)-glyco �-(1-3)- a ratio o ponent, 000 to 2 “Konjac from ko Konjac fl perennia is thewa comannan (more than95%onadryweightbasis),whichconsists of D-mannose and D-glucose units at a molar ratio of 1.6:1.0, connected by �-(1-4)-glycosidic bonds with a branch at about h 50th or 60th unit. About each 19th sugar residue is tylat lecul defi njac oida cies ight, e an :1.0. ,4 lin 0kD ute t 19 ter an 7.0. ition hea ting deta stabl omm orld With intro nal ing ned. to a et al. jac fl s cap osag me dos d for slipi le da ce of s to nce, d repo tis of eport for t ivativ s of o elli ow b nced s the e elde dicat and jac p s of o cap reac houl men be t es (K mentioned, recent research has also focussed on the effects of KGM for the treatment of atopic diseases ic dermatitis, asthma and allergic rhinitis. Onishi et al. ourweek-old NC/Ngamice, awell known animalmodel ermatitis, diets containing 5% each of KGM powder, fied KGM, low-viscous KGM, pulverised KGM (PKGM) ulated fine KGM for 8 weeks. It was reported that the nt of skin inflammation and hyper-IgE production were in mice fed only on the PKGM diet, through systemic ation of IFN-�, a positive regulatory cytokine of atopic mation. r study, Onishi et al. (2007a) examined the effects of cratching behaviour and skin inflammatory immune n 4-week-old NC/Nga mice. They were fed on diet con- M for 8 or 9 weeks and scratching behaviour as well symptoms were evaluated every 2 weeks. According thors, an increase in scratching behaviour was evi- weeks of age in control mice, but this symptom was dently inhibited in PKGM fed mice. Continuous PKGM ificantly inhibited eczematous skin lesions including sis, dermal mastocytosis and eosinophilia. In addi- ous overproductions of substance P, IL-10, IL-4, and all suppressed in PKGM-fed mice. However, the pre- nism(s) underlying the anti-inflammatory action of its effects on the cutaneous response remain to be . and safety of KGM products of safety and efficacy data on the majority of herbal roducts is a major impediment to the integration of icines into conventionalmedical practices (WHO,1998). everal factors which can affect the quality of current ucts. Species and cultivar differences, organ specificity iurnal and seasonal variations can affect the yield of ical constituents in the starting medicinal materials. In ethods of cultivation and harvesting, post-harvest han- anufacturingpractices aswell as the lack of harmonized system in respect of the licensing, dispensing, manu- d trading of herbal medicines or nutraceuticals (WHO, ll affect the quality and consequently the therapeutic final herbal products (Fong, 2002). latory purposes, the European Commission has drawn a between konjac gum and KGM (European Commission, w are the definitions of each: gum is a water-soluble hydrocolloid obtained from jac flour by aqueous extraction. Konjac flour is the ed raw product from the root of the perennial plant ophallus konjac. The main component of konjac gum is er-soluble high-molecular-weight polysaccharide glu- an (more than 75%), which consists of D-mannose and se units at a molar ration of 1.6:1.0, connected by �-(1- sidic bonds. Shorter side chains are attached through glycosidic bonds, and acetyl groups occur at random at f about 1 group per 9 to 19 sugar units. The main com- glucomannan, has an average molecular weight of 200 000 000.” glucomannan is a water-soluble hydrocolloid obtained njac flour by washing with water-containing ethanol. our is the unpurified raw product from the tuber of the l plant Amorphophallus konjac. The main component ter-solublehigh-molecular-weightpolysaccharideglu- eac ace mo The “Ko coll spe we nos 1.6 �-1 200 trib 9 to wa and Add of a hea The KGM e pean C is no w KGM. rently functio depend concer needed (Chan Kon such a daily d a recom Higher mende and dy availab eviden appear flatule monly hepati been r anism its der report from sw have n annou 2002 a and th data in of KGM ing kon report of KGM until it KGM s supple should capsul ed. The main component, glucomannan, has an average ar weight of 500 000 to 2 000 000.” nition of konjac flour given by the U.S. FCC is: flour occurs as a cream to light tan powder. It is a hydro- l polysaccharide obtained from the tubers of various of Amorphophallus. Konjac Flour is a high molecular non-ionic glucomannan primarily consisting of man- d glucose at a respective molar ratio of approximately It is a slightly branched polysaccharide connected by kages and has an average molecular weight of 200 to a. Acetyl groups along the glucomannan backbone con- o solubilityproperties andare located, onaverage, every sugar units. Konjac Flour is dispersible in hot or cold d forms ahighly viscous solutionwith apHbetween4.0 Solubility is increasedbyheat andmechanical agitation. of mild alkali to the solution results in the formation t-stable gel that resists melting, even under extended conditions.” iled standards for the classification of konjac flour and ished by the Chinese Ministry of Agriculture, the Euro- ission and the U.S. FCC are shown in Table 3. There wide agreed regulatory standard for konjac flour or out such an agreed standard, KGM products are cur- duced to the general public as dietary supplements, food, nutraceuticals or prescription herbal medicines, on the licensing policy established by the countries Therefore, harmonization of monographic standards is ssess and ensure the quality of existing KGM products , 2009). our has been formulated into different dosage forms sules, drink mixes, granules and tablets. The optimal e for KGM has yet to be established. For weight loss, nded dosage is 1 g three times a day, 1h before meals. es, ranging from 3.6 to 13g a day, have been recom- managing type2diabetes, insulin-resistance syndrome demia (Keithley and Swanson, 2005). On the basis of ta, it appears to have low toxicity levels and displays no psychotropic activity (Vasques et al., 2008). KGM also be well tolerated; mild gastrointestinal effects such as iarrhoea and abdominal discomfort are the most com- rted (Sood et al., 2008). However, a case report of acute cholestatic type associated with the use of KGM has ed by Villaverde et al. in 2004 and the potential mech- his is the presence of impurities such as serotonin and es (Niwa et al., 2000). Other major concerns are case esophageal and gastrointestinal obstructions resulting ng of the KGM tablets (Fung, 1984; Gaudry, 1985)which een removed from the market. In response to this, FDA the recall of “mini-cup gel candies” containing KGM in y posed a choking risk, particularly to infants, children rly (Sood et al., 2008; Vanderbeek et al., 2007). All these e the importance of quality control to ensure the purity also choosing appropriate dosage forms for market- roducts to safeguard public safety. There have been no esophageal obstruction associated with the ingestion sules as the outer casing shields the fibre from water hes the stomach. In addition, it was recommended that d not be taken in association with medications or other ts that have hypoglycemic effects and oral medications aken one hour before or four hours after ingesting KGM eithley and Swanson, 2005). M. Chua et al. / Journal of Ethnopharmacology 128 (2010) 268–278 275 Table 2 Summary of KGM clinical trials.a. Reference Participants Study design/duration KGM dosing and dosage form Control group Concurrent diet modification Anti-obesity activity Kraemer et al. (2007) Overweight subjects (22 men and 20 women; BMI >25kgm−2) Two 8-wk studies 3 g/day in the form of capsules NA Healthy diet; controlled diet portion 1. KGM diet without exercise 2. KGM diet with exercise 3 weekly sessions of 1.5h Anti-hyperglycemic and hypercholesterolemia activity Vuksan et al. (1999) 11 Hyperlipidemic, hypertensive type 2 diabetic males Double-blind, placebo-controlled, crossover; 3 wk KGM enriched biscuits (15.1 g/day) Placebo biscuits + 14g/day of hard red wheat bran NCEP Step 2 diet Vuksan et al. (2000) 11 Insulin resistance syndrome subjects Double-blind, placebo-controlled, crossover; 3 wk KGM enriched biscuits (8–13g/day) Placebo biscuits (15% polysaccharides, 16% excipients) + 11g/day of hard red wheat bran NCEP Step 2 diet Chen et al. (2003) 22 hypercholesterolemic type 2 diabetics (BMI: 25.5±3.2 kgm−2; FBG: 6.7–14.4mmol/l) Double-blind, placebo-controlled, crossover; 4 wk 3.6 g/day in the form of capsules (progressive dose: 1.2 g for 3 days, 2.6 g for 3 days and 3.6 g for 22 days) Placebo (content NA) – Gallaher et al. (2002) 21 overweight normocholesterolemic (BMI: 28±4.6 kgm−2; fat mass: 31.3±12.7 kg) Non-placebo controlled; 4 wk 2.4 g/day (equal mixture of GM+chitosan) in the form of capsules – – Yoshida et al. (2006) Hyperlipidemic with (18 subjects) or without (16 subjects) type 2 diabetes Double-blind, placebo-controlled, crossover; 3 wk 10g/day as granola bars Placebo (granola bars) Carbohydrate replaced by granola bars Vasques et al. (2008) Obese (treatment group: 32 subjects; placebo group: 26 subjects; BMI: 30–39.9 kgm−2) Double-blind, placebo-controlled; 12 wk Hydroxycitrate (2.5 g) +KGM (1.5 g) in the form of capsules Placebo (content NA) – Laxative effect/prebiotic activity Chen et al. (2006) 8 healthy adults Single-blind, placebo-controlled; 4 wk 4.5 g/day in the form of capsules (progressive dose: 1.5 g/day for 3 days, 3 g/day for 4 days and 4.5 g/day for 21 days) Placebo (corn starch) Low-fibre diet Chen et al. (2008) 7 constipated female Single-blind, placebo-controlled; 4 wk 4.5 g/day in the form of capsules (progressive dose: 1.5 g/day for 3 days, 3 g/day for 4 days and 4.5 g/day for 21 days) Placebo (corn starch) Low-fibre diet Chen et al. (2005) Seven-week old male Balb/c mice (n=48) 2 or 4 wk (time-course study) KGM or KGMO dietb in the form of pellets 5% (w/w) cellulose – 4 wk (dose-dependent study) 2.5%, 5% or 7.5% (w/w) KGM 2.5%, 5% or 7.5% (w/w) KGMO (both in the form of pellets) 5% (w/w) cellulose AIN-93 fibre free diet Elamir et al. (2008) Twelve-week old Wister mice (n=40) 14 wk Standard dietc + 5% (w.v) KGMO Standard diet – Anti-inflammatory activity Onishi et al. (2004) Four-week old male Nc/Nga mice (5 groups, n=5) 8 wk MF diet +5% (w/w) each of KGM powder (75% GM), highly purified KGM powder (99% GM), PKGM (97% GM) or re-granulated fine KGM (97% GM)d MF diet – Onishi et al. (2007a) Four-week old Nc/Nga mice 8–9 wk MF diet +0.2, 1 or 5% (w/w) PKGM powder MF diet – Onishi et al. (2007b) Four-week old female Balb/c mice 8 wk MF diet +5% (w/w) highly viscous KGM (98.1% GM) or PKGM (97% GM) MF diet – a AIN, American Institute of Nutrition; BMI, bodymass index; FBG, fasting blood glucose; KGMO, konjac glucomannan oligosaccharides;MF,modified fat; NA, not available; NCEP, National Cholesterol Education program; PKGM, pulverised konjac glucomannan. b KGM or KGMOdiet composition (g/kg): casein =200; corn starch=525.9; sucrose =100; corn oil = 70; AIN-93Gmineral mix =35; AIN-93 vitaminmix=1.0; L-cystine =3.0; choline bitartrate =2.5; butylated hydroxytoluene=0.014; KGM or KGMO=50. c Standard diet = “rat and mouse standard diet”. d Particle size. KGM powder and highly purified KGM powder =300�m; PKGM=100�m; re-granulated fine KGM=160�m. 276 M. Chua et al. / Journal of Ethnopharmacology 128 (2010) 268–278 Table 3 Standards (% in w/w) for the classification of konjac flour and KGM (Chinese Ministry of Agriculture, 2002; European Commission, 2001; FCC, 1996). Konjac flour Konjac glucomannan Chinese Ministry of Agriculture European U.S.A. Food Chemicals Codex Chinese Ministry of Agriculture European Commission Glucomanna Sulphur diox Loss on dryi Total ash Arsenic (mg Lead (mg/kg Starch (%) Protein (%) Ether-solubl Chloride Salmonella s E. coli Viscosity a 800 ◦C, 3–4 9. Discussi Konjac c have longes tives and d konjac also In the W dietary sup efits such as there is also tical or as a The pha potential o medical con hyperchole tries are in such as foo of metabol mented the required ph cost-effecti in prebiotic been shown and promot the science studies usin Before K tice, the iss taken into affect the e previously, establishing facture and the science the manufa majority of properties, use in drug properties. internation the biology vation of th this issue is tication of k to produce elati ial l ets h arve ater and rnat prov d th mole pro o far m an ting excl kely Furt teris tiesd utur wou f kon atogr atogr ry, u ches 2005 Commission n (%) >70 >75 >75 ide (g/kg) M. Chua et al. / Journal of Ethnopharmacology 128 (2010) 268–278 277 References Al-Ghazzewi, F.H., Khanna, S., Tester, R.F., Piggott, J., 2007. The potential use of hydrolysed konjac glucomannan as a prebiotic. Journal of the Science of Food and Agriculture 87, 1758–1766. Alonso-Sande, mannan, a Journal of Alvarez-Manc comannan controlled of Pharma BioMatNet (B A New V tries. Acc org/public BMA (BritishM GroupLtd 210. Brown, D., 200 Chan, K., 2005 ical concep Chan, K., Leun needed to 4, 18. Chen, H.L., Che ative by in Nutrition 2 Chen, H.L., Che jac glucom and impro controlled Chen,H.L., Fan glucomann 1059–106 Chen, H.L., She viated hyp randomize 36–42. Chinese Minis Available a Douglas, J.A., konjac) pro Douglas, J.A., F yield of ko Journal of Elamir, A.A., T N.A., Piggo microflora En, S.C., 2008. Anhui Agr European Com Directive Other tha http://eurl 0023:EN:P Fang, W.X., W phophallus 167–170. FCC (Food Che Nov 2009. Follett, J.M., D Zealand. C 186–190. Fong, H.H.S., 2 issues and FSA (Food S their E N gov.uk/saf Fung,M., 1984 Gallaher, C.M. reduction absorption 2753–275 Gallaher, D.D. R., Wise, J plasma ch cholestero 433. Gaudry, P., 19 204. Hetterscheid, about Amo 7–129. Keithley, J., Sw tives Thera Kok,M.S., Abdelhameed, A.S., Ang, S., Morris, G.A., Harding, S.E., 2009. A novel global hydrodynamic analysis of the molecular flexibility of the dietary fibre polysac- charide konjac glucomannan. Food Hydrocolloids 23, 1910–1917. Kraemer,W.J., Vingren, J.L., Silvestre, R., Spiering, B.A., Hatfield, D.L., Ho, J.Y., Fragala, M.S., Maresh, C.M., Volek, J.S., 2007. Effect of adding exercise to a diet containing oman , H., 1 in Jap , J., W activi –740 , Lin, Z a. Act 2004 ., 199 pl. X) L., Li, biodiv rsity a , Trusw York J., Bog . y, B.V i, K., acteri 222. ., Etoh Konn hemis , S., K nese). ., Kaw imot taneo . Biofa N., Ka ide, ses sc ga m ., Kaw imot ents t ice. B C.J., evelo , Bake ose co a-anal a, N., eight istry i, S., 2 ydroc i, S., T cture o S.M., s, New State and E ://ww eek, P a hyg 45, 80 , C.A.R P., Alo ia cam eraph de, A.F e hep (Amor V., Je henti, nan) i ase in V., Sie E., Bri ts of v tance V., Sie r, L.A emerg rican M., Teijeiro-Osorio, D., Remunan-Lopez, C., Alonso, M.J., 2009. Gluco- promising polysaccharide for biopharmaceutical purposes. European Pharmaceutics and Biopharmaceutics 72, 453–462. enido, F., Landin, M., Lacik, I., Martinez-Pacheco, R., 2008. Konjac glu- and konjac glucomannan/xanthan gum mixtures as excipients for drug delivery system. Diffusion of small drugs. International Journal ceutics 349, 11–18. iological Materials for Non-food products), 2000. Glucomannan: egetal Texturing Agent for European Food and Non-food Indus- essed 15 September 2009. Available at: http://www.biomatnet. ations/f4106fin.pdf. edical Association), 2005. BritishNational Formulary. BMJ Publishing andRoyal Pharmaceutical SocietyofGreatBritain, London, p. 134, 209, 0. Aroids, Plants of the Arum Family. Timber Press, Portland, Oregon. . Chinese medicinal materials and their interface with Western med- ts. Journal of Ethnopharmacology 96, 1–18. g, K.S., Zhao, S.S., 2009. Harmonization of monographic standards is ensure the quality of Chinese medicinal materials. Chinese Medicine ng, H.C., Liu, Y.J., Liu, S.Y., Wu,W.T., 2006. Konjac acts as a natural lax- creasing stool bulk and improving colonic ecology in healthy adults. 2, 1112–1119. ng, H.C., Wu, W.T., Liu, Y.J., Liu, S.Y., 2008. Supplementation of kon- annan into a low-fibre Chinese diet promoted bowel movement ved colonic ecology in constipated adults: a placebo-controlled, diet- trial. Journal of the American College of Nutrition 27, 102–108. , Y.H., Chen,M.E., Chan, Y., 2005. Unhydrolyzed andhydrolyzed konjac ansmodulated cecal and fecalmicroflora inBalb/cmice.Nutrition21, 4. u, W.H., Tai, T.S., Liaw, Y.P., Chen, Y.C., 2003. Konjac supplement alle- ercholesterolemia and hyperglycemia in type 2 diabetic subjects–a d double-blind trial. Journal of the American College of Nutrition 22, try of Agriculture, 2002. Konjac flour. Accessed 5 September 2009. t: http://www.konjacfoods.com/pdf/NY494-cn.pdf. Follett, J.M., Waller, J.E., 2005. Research on konjac (Amorphophallus duction in New Zealand. Acta Horticulturae 670, 173–180. ollett, J.M.,Waller, J.E., 2006. Effect of threeplant densities on the corm njac (Amorphophallus konjac) grown for 1 or 2 years. New Zealand Crop and Horticultural Science 34, 139–144. ester, R.F., Al-Ghazzewi, F.H., Kaal, H.Y., Ghalbon, A.A., Elmegrahai, tt, J.R., 2008. Effects of konjac glucomannan hydrolysates on the gut of mice. Nutrition and Food Science 38, 422–429. Current production of konjac: problems and strategies. Journal of icultural Science 36, 14792–14793 (in Chinese). mission, 2001. Commission Directive 2001/30/EC of 2001, Amending 96/77/EC Laying Down Specific Purity Criteria on Food Additives n Colours and Sweeteners. Accessed 30 Nov 2009. Available at: ex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2001:146:0001: DF. u, P.W., 2004. Variations of konjac glucomannan (KGM) from Amor- konjac and its refined powder in China. Food Hydrocolloids 18, micals Codex), 1996. Revised Monograph-Konjac Flour. Accessed 30 Available at: http://www.nap.edu/html/fcc/konjac.pdf. ouglas, J.A., 2002. Konjac production in Japan and potential for New ombined Proceedings International Plant Propagators’ Society 52, 002. Integration of herbal medicine into modern medical practices: prospects. Integrative Cancer Therapies 1, 287–293. tandards Agency), 2007. Current EU Approved Additives and umbers. Accessed 27 Nov 2009. Available at: http://www.food. ereating/chemsafe/additivesbranch/enumberlist. . Glucomannan diet tablets. TheMedical Journal of Australia 146, 350. , Munion, J., Hesslink, R., Wise, J., Gallaher, D.D., 2000. Cholesterol by glucomannan and chitosan is mediated by changes in cholesterol and bile acid and fat excretion in rats. The Journal of Nutrition 130, 9. , Gallaher, C.M., Mahrt, G.J., Carr, T.P., Hollingshead, C.H., Hesslink, ., 2002. A glucomannan and chitosan fibre supplement decreases olesterol and increases cholesterol excretion in overweight normo- lemic humans. Journal of the American College of Nutrition 21, 428– 85. Glucomannan diet tablets. The Medical Journal of Australia 142, W.L.A., Ittenbach, S., 1996. Everything you always wanted to know rphophallus but were afraid to stick your nose into. Aroideana 19, anson, B., 2005. Glucomannan and obesity: a critical review. Alterna- pies in Health and Medicine 11, 30–34. gluc Kurihara tion Li, B., Xia sity 7404 Liu, P.Y. Chin Liu, P.Y., Long, C.L (Sup Long, C. agro dive Mann, J. New Mayo, S. Kew McClear 3–9. Nishinar char 199– Niwa, T from Bioc Okimasu Japa Onishi, N Hash spon size Onishi, K., H pres NC/N 104. Onishi, N Hash prev in m Prychid, tal d 995. Sood, N. gluc met Sugiyam lar w Chem Takigam of H Takigam stru Talbott, Pres United cal http Vanderb from ogy Vasques M.S. Garc toth Villaver Acut nan Vuksan, Brig man dise Vuksan, gen, effec resis Vuksan, Leite ing: Ame nan. Metabolism Clinical and Experimental 56, 1149–1158. 979. Trends and problems of konjac (Amorphophallus konjac) cultiva- an. Japan Agricultural Research Quarterly 13, 174–179. ang, Y., Xie, B.J., 2005. Grain-size effect on the structure and antiobe- ty of konjac flour. Journal of Agricultural and Food Chemistry 53, 7. .S., Guo, Z.X., 1998. Research and Utilization of Amorphophallus in a Botanica Yunnanica (Suppl. X), 48–61. . Konjac. China Agriculture Press, Beijing (in Chinese). 8. Ethnobotany of Amorphophallus of China. Acta Botanica Yunnanica , 89–92. H., Ouyang, Z.Q., Yang, X.Y., Li, Q., Trangmar, B., 2003. Strategies for ersity conservation and promotion: a case from Yunnan, China. Bio- nd Conservation 12, 1145–1156. ell, A.S., 2007. Essentials ofHumanNutrition.OxfordUniversity Press, , pp. 443. ner, J., Boyce, P.C., 1997. TheGenera of Araceae. Royal BotanicGardens, ., 2003. Dietary fibre analysis. Proceedings of the Nutrition Society 62, Williams, P.A., Phillips, G.O., 1992. Review of the physico-chemical stics and properties of konjac mannan. Food Hydrocolloids 6, , H., Shimizu, A., Shimizu, Y., 2000. Cis-N-(p-Coumaroyl)serotonin yaku, Amorphophallus konjac K. Koch. Bioscience. Biotechnology and try 64, 2269–2271. ishida, N., 1982. Hiroshima Joshi Daigaku, Kaseigakubu Kiyo 13, 1 (in amoto, S., Nishimura, M., Nakano, T., Aki, T., Shigeta, S., Shimizu, H., o, K., Ono, K., 2004. The ability of konjac-glucomannan to suppress usly occurring dermatitis in NC/Nga mice depends upon the particle ctors 21, 163–166. wamoto, S., Suzuki, H., Santo, H., Aki, T., Shigeta, S., Hashimoto, M., Ono, K., 2007a. Dietary pulverized konjac glucomannan sup- ratching behavior and skin inflammatory immune responses in ice. International Archives of Allergy and Immunology 144, 95– amoto, S., Ueda, K., Yamanaka, Y., Katayama, A., Suzuki, H., Aki, T., o, K., Hide, M., Ono, K., 2007b. Dietary pulverized konjac glucomannan he development of allergic rhinitis-like symptoms and IgE response ioscience, Biotechnology and Biochemistry 71, 2551–2556. Jabaily, R.S., Rudall, P.J., 2008. Cellular ultrastructure and crys- pment in Amorphophallus (Areceae). Annals of Botany 101, 983– r,W.L., Coleman, C.I., 2008. Effect of glucomannan on plasma lipid and ncentrations, body weight and blood pressure: systemic review and ysis. American Journal of Clinical Nutrition 88, 1167–1175. Shimahara, H., Andoh, T., Takemoto, M., Kamata, T., 1972. Molecu- s of konjac mannans of various sources. Agricultural and Biological 36, 1381–1387. 000. Konjacmannan. In: Phillips, G.O.,Williams, P.A. (Eds.), Handbook olloids. CRC Press, Florida, pp. 413–424. akiguchi, T., Phillips, G.O., 1997. Microscopical studies of the tissue f konjac tubers. Food Hydrocolloids 11, 479–484. 2003. A Guide to Understanding Dietary Supplements. The Haworth York. s Department of Agriculture, 2004. Dr. Duke’s Phytochemi- thnobotanical Databases. Accessed 10 Sept 2009. Available at: w.sugarwise.net/pdf/20070110144717.pdf. .B., Fasano, C., O’Malley, G., Hornstein, J., 2007. Esophageal obstruction roscopic pharmacobezoar containing glucomannan. Clinical Toxicol- –82. ., Rossetto, S., Halmenschlager, G., Linden, R., Heckler, E., Fernandez, nso, J.L.L., 2008. Evaluation of the pharmacotherapeutic efficacy of bogia plus Amorphophallus konjac for the treatment of obesity. Phy- y Research 22, 1135–1140. ., Benlloch, S., Berenguer, M., Rayon, J.M., Pina, R., Berenguer, J., 2004. atitis of cholestatic type possibly associatedwith the use of glucoman- phophallus konjac). Journal of Hepatology 41, 1061–1067. nkins, D.J.A., Spadafora, P., Sievenpiper, J.L., Owen, R., Vidgen, E., F., Josse, R., Leiter, L.A., Thompson, C.B., 1999. Konjac-mannan (gluco- mproves glycemia and other associated risk factors for coronary heart type 2 diabetes. Diabetes Care 22, 913–919. venpiper, J.L., Owen, R., Swilley, J.A., Spadafora, P., Jenkins, F.J.A., Vid- ghenti, F., Josse, R.G., Leiter, L.A., Xu, Z., Novokmet, R., 2000. Beneficial iscous dietary fibre from konjac-mannan in subjects with the insulin syndrome. Diabetes Care 23, 9–14. venpiper, J.L., Xu, Z., Wong, E.Y.Y., Jenkins, A.L., Beljan-Zdravkovic, U., ., Josse, R.G., Stavro, M.P., 2001. Konjac-mannan and American gins- ing alternatives therapies for type 2 diabetes mellitus. Journal of the College of Nutrition 20, 370S–380S. 278 M. Chua et al. / Journal of Ethnopharmacology 128 (2010) 268–278 Wang, C.H., Lai, P., Chen, M.E., Chen, H.L., 2008. Antioxidative capacity produced by Bifidobacterium and Lactobacillus acidophilus-mediated fermentations of konjac glucomannan and glucomannan oligosaccharides. Journal of the Science of Food and Agriculture 88, 1294–1300. World of Food Science, 2003. Part II: Konjac-A Program to Help Reduce Poverty in Northern Guangdong, China. Accessed 31 Aug 2009. Available at: http://www.worldfoodscience.org/cms/?pid=1003561. Wootton, A.J., Luker-Brown,M.,Westcott, R.J., Cheetham, P.S.J., 1993. The extraction of a glucomannan polysaccharide from konjac corms (Elephant Yam, Amor- phophallus rivierii). Journal of the Science of Food and Agriculture 61, 429–433. World Health Organization, 1998. Regulatory Situation of Herbal Medicines- A Worldwide Review. Accessed 25 Sept 2009. Available at: http://apps. who.int/medicinedocs/fr/d/Jwhozip57e/3.1.html. Xu, L., Xu, H.H., Huang, T.S., Du, T.F., He, X.R., Shen, L.H., 2001. New Techniques of Cultivation for Good Agricultural Practice (GAP) and Industrializing Develop- ment on the Chinese Rare-medicinal Herbs. Xie He Medical University, Beijing (in Chinese). Yoshida, M., Vanstone, C.A., Parsons, W.D., Zawistowski, J., Jones, P.J.H., 2006. Effect of plant sterols and glucomannan on lipids in individuals with and without type II diabetes. European Journal of Clinical Nutrition 60, 529–537. Yunnan Fuyuan Jintianyuan Agricultural Development Company Ltd., 2008. Accessed 5 Sept 2009. Available at: www.jty.cn (in Chinese). Zhang, Y.Q., Xie, B.J., Gan, X., 2005. Advance in the applications of konjac glucoman- nan and its derivatives. Carbohydrate Polymers 60, 27–31. Traditional uses and potential health benefits of Amorphophallus konjac K. Koch ex N.E.Br. Introduction Traditional and contemporary uses of konjac corms Cultivation of Amorphophallus konjac The molecular composition of Amorphophallus corm tissue Localisation, structure and physicochemical properties of KGM Commercial production and processing of KGM Potential health benefits of KGM Anti-obesity activity Anti-hyperglycemic and hypercholesterolemia activities Laxative effect Prebiotic activity Anti-inflammatory activity Quality and safety of KGM products Discussion Acknowledgement References