Flavonoids of Pallenis spinosa (Asteraceae)

Biochemical Systematics and Ecology, Vol. 20, No. 8, pp. 785-786, 1992. 0305-1978/92 $5.00 + 0.00 Printed in Great Britain. Pergamon Press Ltd. Flavonoids of Pallenis spinosa (Asteraceae) AHMED A. AHMED, MARK SPALLER* and TOM J. MABRYt Department of Chemistry, Faculty of Science, EI-Minia University, EI-Minia, Egypt; *Department of Chemistry and tDepartment of Botany, the University of Texas at Austin, Austin, TX 78713. U.S.A. Key Word Index--Pallenis spinosa; Asteraceae; Inuleae; flavone and flavonol glycosides Abstract--Pallenis spinosa was investigated for its flavonoid content. Two mono- and diglycosides of patuletin, a quercetin monoglycoside, t~NO tricin monoglycosides, and four methoxylated flavonols were reported. Introduction The monotypic genus Pallenis (Asteraceae: Inuleae) was placed in subtribe Inulinea. Merxmuller et al. (1977) classified the subtribe Inulinea into three groups, in one of which Pallenis has been recognized close to the genera Asteriscus, Bubonium and Rhanterium. On the other hand, Pallenis spinosa (L.) Cass has been given the name Asteriscus spinosa G. et G. (C. Pignatti, 1982) and considered as a member of the genus Asteriscus. Therefore, we investigated the flavonoid constituents of Pallenis spinosa to assess whether or not the phytochernical pattern could justify the inclusion of this plant in a genus different from Asteriscus. The species is common in the Mediterranean area and in Egypt it is widespread throughout the Mediterranean coast. Materials and Methods Aerial parts from flowering plants of Pa//en/ssp/nosawere collected from Bourg El-Arab, Egypt, in March, 1987. A voucher, Ahmed 89/6, is in the herbarium of the University of El-Mini& The plant material (1 kg) was extracted with 80% and then 50% aqueous EtOH. The combined extracts were concentrated and chromato- graphed over polyamide, eluted first with H20 and then with increasing amounts of EtOH. The isolated compounds were purified over Sephadex LH-20 prior to analysis by standard techniques (Mabry et al., 1970; Markham, 1982) Acid hydrolysis of the glycosides (1 N HCI, 1 h) yielded the sugar residues and the aglycones, all of which were co-chromatographed with authentic samples. 1H-NMR spectra of the TMSi ethers of all flavonoids were recorded in CDCI 3 at 400 MHz. Results and Discussion Pallenis spinosa afforded 11 known flavonoids including the 3-O-I~-D-galactoside, 7-O-6-o-galactoside and 3-O-0~-L-rharnnosyl (1-6)-I~-D-galactoside of patuletin, the 5-O-]]-D-glucoside and 7-O-I~-mglucoside of tricin, the 3-O-6-D-galactoside of quercetin and the aglycones kaempferol 3-methyl ether, quercetin 3-rnethyl ether, patuletin, and the 3,5,6,7,3'-pentarnethyl ether and 3,5,6,7,3',4'-hexamethyl ether of quercetagetin. The investigation of the flavonoid constituents of Asteriscus graveolens showed the presence of a diglycoside of tamarixtin, two rnonoglycosides of kaernpferol and quercetin and three aglycones (Ahmed et al., 1991) and A. pygrneous yielded a diglycoside of chrysoeriol, a monoglycoside of apigenin and luteolin and two aglycones (Ahmed, 1992). The terpenoid constituents of two members of the genus Asteriscus, A. graveolens (EI-Dahmy et aL, 1985) and A. sericeus (Jakupovic et aL, 1987) afforded hurnulene derivatives. Besides, A. pygmeous revealed farnesol glucosides (Ahrned, 1992), while Pallenis spinosa gave eudesrnane and oplopanone derivatives (Appendio et aL, 1989, Ahrned et aL, 1990). (Received 11 May 1992) 785 786 A.A. AHMED ETAL. In conc lus ion , the accumulat ion of a 5 -O-g lycosy l f lavone in Pallenis spinosa repre- sents a chemotaxonomic character. Fur thermore , the te rpeno id chemis t ry cou ld suppor t its separat ion f rom Asteriscus. P lacement in the Inula group may be suppor ted by f lavono id pat terns and by eudesmane der ivat ives , wh ich are common wi th in the members o f the group. Acknowledgements--A. Ahmed thanks the Alexander von Humboldt-Stiftung for the financial support of a Kanuer HPLC. The work was supported at The University of Texas at Austin by the National Institute of Health (GM-35710) and the Robert A. Welch Foundation (Grant F-130). References Ahmed, A. A. (1992) Farnesol and thymol derivatives from Asteriscuspygmaeus. J. Nat. Prod. 55, 825-827. Ahmed, A. A., Ishak, M. S., Micheal, H. N., EI-Ansari, M. A. and EI-Sisi, H. I. (1991) Flavonoids of Asteriscus graveolens. J. Nat. Prod. 54, 1092-1093. Ahmed, A. A., Jakupovic, J. and Bohlmann, F. (1990) Dihydroxypallenone, a new sesquiterpene with a new carbon skeleton from Pallenis spinosa. Phytochemistry29, 3355-3358. Appendio, G., Gravotto, G., Gariboldi, P., Claudi, F. and Picci, V. (1989) A sesquiterpene alcohol from Pallenis spinosa. Phytochemistry 28, 549-850. EI-Dahmy, S., Jakupovic, J., Bohlmann, F. and Sarg, T. M. (1985) New humulene derivatives from Asteriscus graveolens. Tetrahedron 41,309-316. Jakupovic, J., Lehmann, L., Bohlmann, F. and Hodgson, A. A. (1987) Nerolidol derivatives from Asteriscus sericeus. Phytochemistry 26, 2854-2855. Mabry, T. J., Markham, K. R. and Thomas, M B. (1970) The Systematic Identification of Flavonoids. Springer, New York. Markham, K. R. (1982) Techniques of Flavonoidldentification. Academic Press, London. Merxmuller, H., Leins, P. and Rosseler, H. (1977) Inuleae--systematic review. In The Biology and Chemistry of the Composs~ae (Heywood, V. H., Harborne, J. B. and Turner, B. L., eds), pp. 577-602. Academic Press, London. Pignatti, S. (1982) Flora d'ltalia, Vol. Ill. p. 52 Edagricole, Bologna.