Saponins from Agrostemma gracilis BOISS

The genus Agrostemma, belonging to the Caryophyllaceae family, is represented by two species in Turkey [1]. Although the genus is known to be toxic, some species has been used for the treatment of cancer in European folk medicine [2]. Saponins, flavonoid glycosides and anthocyanins were isolated from the genus Agrostemma previously [3,4]. It has been reported that extracts of some Agrostemma species exhibited cytotoxic [5], antihypercholesterolaemic and antioxidant activities [6].

In this study, dried and ground plant material (whole plant) was extracted with MeOH, and then treated with hexane. The residue was fractionated over Sephadex LH-20. The saponin-rich fractions were purified by various chromatographic techniques and gave four new oleanane-type saponins. The structures of the compounds were determined as 3-O-β-D-xylopyranosyloleanolic acid 28-O-β-D-glucopyranosyl-(1→2)-[β-D-xylopyranosyl-(1→6)]-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester, 3-O-α-L-rhamnopyranosyl-(1→2)-β-D-xylopyranosyloleanolic acid 28-O-β-D-glucopyranosyl-(1→2)-[β-D-xylopyranosyl-(1→6)]-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester, 3-O-β-D-xylopyranosylechinocystic acid 28-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester, 3-O-β-D-xylopyranosylechinocystic acid 28-O-β-D-glucopyranosyl-(1→2)-[β-D-xylopyranosyl-(1→6)]-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester by a combination of one- and two-dimensional NMR techniques, and mass spectrometry. This is the first phytochemical report on Agrostemma gracilis BOISS.

References: [1] Davis, PH. (1967) Flora of Turkey and East Aegean Islands, Edinburgh University Press., Great Britain.

[2] Duke, J.A. (1985) Handbook of Medicinal Herbs, CRC Press, Boca Raton, FL.

[3] Siepmann, C. et al. (1998) Planta Med. 64:159–164.

[4] Ferry, S., Darbour, N. (1980) Plant. Med. Phyt. 14:148–154.

[5] Hebestreit, P., Melzig, M.F. (2003) Planta Med. 69:921–925.

[6] Avcı, G. et al. (2006)J. Ethnopharmacol. 107:418–423.