Steroidal Saponins from Solanum torvum Swartz Collected in Dibombari, Cameroon

Abstract

Aims: This work aimed to investigate the phytochemical constituents of Cameroonian species of Solanum torvum Swartz and to carry out. Antioxidant, enzyme inhibition (urease and glucosidase) and antibacterial activities of methanol crude extract and isolated compounds.  Methodology: The stems of Solanum torvum were collected and extracted by maceration in methanol. The crude extract was subjected to repeated column chromatographic separation. Their structures were elucidated on the basis of spectral analysis of ESI-MS, 1D and 2D NMR. The methanol crude extract and pure compounds were tested against Pseudomonas aeruginosa, Escherichia coli, Proteus mirabilis, Salmonella typhi, Klebsiella pneumonia, Staphylococcus aureus, Streptococcus faecalis, Micrococcus sp. and Saccharomyces cerevisiae using the method of disk diffusion. The radical scavenging (DPPH) and the enzyme inhibition (urease and glucosidase) were perfomed according to the standards methods Results: One new compound neochlorogenin-6-O-β-D-xylopyranosyl-(1→3)-α-D-quinovopyranoside, together with eight known compounds including four steroidal derivatives, neochlorogenin-6-O-β-L-rhamnopyranosyl-(1→3)-β-D-quinovopyranoside, yamogenin-3-O-β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranoside, diosgenin, chlorogenin; three phytosterols stigmasterol, β-sitosterol, β-sitosterol-3-O-β-D-glucopyranoside and one pentacyclic derivative, betullinic acid were isolated from the stems of Solanum torvum.. Diosgenin was isolated from S. torvum for the first time. All the tested compounds were found to be inactive while methanol crude extract showed moderate urease and significant glucosidase inhibition activities with IC50 = 61.2± 0.68 and 32.5± 0.87 µM respectively. Conclusion: These results suggested that Solanum torvum might be used as an enzyme inhibition agent particularly for alpha glycosidase inhibition.