Phytochemical and bioactivity evaluation of Senna didymobotrya fresen irwin used by the Nandi community in Kenya

Abstract

Medicinal plants play a vital role in the traditional treatment of various diseases in Africa and the world at large. In Nandi county rift valley province in Kenya Senna didymobotyya is one of the most valued plants traditionally, this is mainly attributed to the famous mursik milk in which the plant is used as a preservative. A study was carried out to investigate the bioactivity of the plant leaves. Organism tested were Escherichia coli, Salmonella typhi, Enterobacter aerogenes , Klebsiella sp., Streptococcus pyogenes isolated from clinical specimens, and Proteus vulgaris and Bacillus cereus , obtained as standard isolates from commercial source. From the study Senna didymobotrya was found to contain secondary metabolites, saponins, flavonoids, tannins, phenols, steroids, steroidal ring (glycone portions of the glycoside), steroidal nucleus (glycone portion of the glycoside) and cardiac glycosides. The plant leaves were found not to contain alkaloids, terpenoids and anthroquinones. The bioactivity of the plant extract observed in this study can be attributed to the presence of these phytochemicals. Results from the bioassay Senna extract showed the highest zone of inhibition was obtained against Bacillus cereus at 500 mg/ml and its minimum inhibitory concentration was 31.25 mg/ml. The extract was also active against all the organisms at 500 mg/ml. Its minimum inhibitory concentration was 250 mg/ml for Streptococcus pyogenes , Escherichia coli and Proteus vulgaris .