Saba senegalensis (A. DC.) Pichon (Apocynaceae) known locally in Ghana as Sono nantin (Asante-Twi) is used in traditional folk medicine to treat inflammatory related conditions such as burns and pulmonary troubles [1]. However, its pharmacological activities and phytochemical principles have not been investigated. The present study combined a number of chromatographic techniques to isolate two steroidal alkaloids from the stems: one novel and another previously known.
Extensive spectroscopic analysis including 1D and 2D NMR established the novel alkaloid as Homoandrost-9-ene-17β,17aβ-diol-3β-(methylamino)-17aα-methyl-12-one and the known one as pregnane steroidal alkaloid Irehine (synonym: Buxomegine) [2].
Irehine displayed potent cytotoxic activity (IC50) against human cancer cell lines HL-60 (17.35 µM), MCF-7 (16.56 µM), SW-480 (16.89 µM) in the MTS cytotoxic assay [3] but no significant nitric oxide inhibitory activity in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells. This is the first report of Irehine in the genus Saba.
Acknowledgements: OWSD (Organisation for Women in Science for the Developing World) and Sida (Swedish International Development Cooperation Agency) for sponsorship
Keywords: Saba senegalensis, Apocynaceae, steroidal alkaloid, cytotoxicity, nitric oxide inhibition
References:
[1] Burkill HM. The useful plants of west tropical Africa, Vols. 1-3, Royal Botanic Gardens, Kew; 1995: 168-169.
[2] Tomko J, Votický Z, Paulik V, Vassova A, Bauerova O. Chemical Papers 1964; 18(10): 721-731.
[3] Monks A, Scudiero D, Skehan P, Shoemaker R, Paull K, Vistica D, Hose C, Langley J, Cronise P, Vaigro-Wolff, A. J Natl Cancer Inst 1991; 83(11): 757-766.