Brine shrimp cytotoxicity of crude methanol extract and antispasmodic activity of α-amyrin acetate from Tylophora hirsuta wall

Background: We have previously reported that aerial parts of Tylophora hirsuta have antispasmodic profile. The current work is an attempt for isolation of pharmacologically active compound(s) that contribute for its antispasmodic activity.

Methods: Preliminary phytochemical screening for crude methanol extract of Tylophora hirsuta (Th.Cr) is performed. Brine shrimp cytotoxicity of crude methanol extract is performed. Column chromatography was used for isolation of compounds. Mass spectroscopy, H(1) NMR and C(13) NMR were used for structural determination of compounds. α-amyrin acetate was tried for possible spasmolytic activity in rabbit's jejunal preparations and KCl-induced contractions.

Results: Th.Cr tested positive for saponins, Alkaloids, Flavonoids and Terpenoids. Compound 1 was isolated as α-amyrin acetate. Compound 2 was heptaeicosanol. Crude methanol extract tested positive for brine shrimp cytotoxicity with LC(50) 492.33± 8.08 mg/ml. Compound 1 tested positive for antispasmodic activity on spontaneous rabbits' jejunum preparations with EC(50) (60 ± 2) × 10(-5)M. The compound also tested positive on KCl induced contractions with EC(50) (72 ± 3) × 10(-5)M.

Conclusions: The present work confirms that α-amyrin acetate is has antispasmodic profile and the relaxant effect may be attributed to α-amyrin acetate which is a major compound.