Three New Triterpenoid Saponins from Ixeris sonchifolia and their Cytotoxic Activity

Abstract

Bioassay-guided fractionation of an active n-BuOH extract of the whole plant of Ixeris sonchifolia, using a cytotoxicity assay, resulted in the isolation of three new triterpenoid saponins, ixeris saponins A (1), B (2), and C (3). On the basis of chemical evidence and extensive spectral studies, their structures were established as echinocystic acid 3-O-β-D-glucopyranosyl(1→3)-β-D-glucopyranosyl(1→3)-α-L-arabinopyranoside (1), 3-O-{bis[β-D-glucopyranosyl(1→2 and 1→3)-α-L-arabinopyranosyl]}echinocystic acid 28-O-β-D-glucopyranosyl ester (2), and 3-O-[β-D-glucopyranosyl(1→3)-β-D-glucopyranosyl(1→3)-α-L-arabinopyranosyl]-16α, 23-dihydroxyolean-12-ene 28-O-β-D-glucopyranosyl ester (3). Compounds 2 and 3 showed significant cytotoxicity against cancer cell lines A375, L929, and HeLa with IC₅₀ values ranging from 8.83 μM to 15.83 μM, while compound 1 was inactive against these three cell lines.

Key words

Ixeris sonchifolia - Compositae - triterpenoidal saponins - ixeris saponins A - C - cytotoxic activity

References

• 1 Jiangsu Medical C ollege. Encyclopedia of Chinese Materia Medica. Shanghai Science and Technology Press 1977: pp 1300-1
• 2 Asada H, Miyase T, Fukushima S. Sesquiterpene lactones from Ixeris tamagawaensis Kitam.  Chem Pharm Bull. 1984;  32 1724-8
• 3 Asada H, Miyase T, Fukushima S. Sesquiterpene lactones from Ixeris tamagawaensis Kitam II.  Chem Pharm Bull. 1984;  32 3036-42
• 4 Asada H, Miyase T, Fukushima S. Sesquiterpene lactones from Ixeris tamagawaensis Kitam III.  Chem Pharm Bull. 1984;  32 3403-9
• 5 Chung H, Woo W, Jalim S. Dentalactone, a sesquiterpene from Ixeris dentata .  Phytochemistry. 1994;  35 1583-4
• 6 Feng X Z, Xu S X, Dong M. A new sesquiterpene lactone glucoside from Ixeris sonchifolia .  J Asian Nat Prod Report. 2001;  3 247-51
• 7 Shiojima K, Suzuki H, Kodera N, Ageta H, Chang H, Chen Y. Composite constituents: thirty-nine triterpenoids including two novel compounds from Ixeris chinensis .  Chem Pharm Bull. 1996;  44 509-14
• 8 Feng X Z, Dong M, Xu S X. A new triterpenoidal saponin from Ixeris sonchifolia and its cytotoxic activity.  Pharmazie. 2001;  56 663-4
• 9 Kamerling J P, Gerwig G J, Vliegenthart J FG. Characterization by gas-liquid chromatography-mass spectrometry and proton-magnetic-resonance spectroscopy of pertrimethylsilyl methyl glycosides obtained in the methanolysis of glycoproteins and glycopeptides.  The Biochem Journal. 1975;  151 491-5
• 10 Gerwig G J, Kamerling J P, Vliegenthart J FG. Determination of the d and l configuration of neutral monosaccharides by high-resolution capillary GLC.  Carbohydrate Research. 1978;  62 349-57
• 11 Dong M, Feng X Z, Wang B X, Wu L J, Ikejima T. Two novel furostanol saponins from the rhizomes of Dioscorea panthaica Prain et Burkill and their cytotoxic activity.  Tetrahedron. 2001;  57 501-6
• 12 Zhang Z, Koike K, Jia Z, Nikaido T, Guo D, Zheng J. Triterpenoidal saponins acylated with two monoterpenic acids from Gleditsia sinensis .  Chem Pharm Bull. 1999;  47 388-93
• 13 Plasman V, Braekman J, Daloze D, Luhmer M, Windsor D, Pasteels J. Triterpene saponins in the defensive secretion of a chrysomelid beetle, Platyphora ligata .  J Nat Prod. 2000;  63 646-9