Antimicrobial and phytochemical study of the bioactive fractions of Guiera senegalensis from Alasan Tambuwal, Nigeria

Abstract

The study was carried out to assess the phytochemical constituents of the bioactive fractions of Guiera senegalensis leaf extracts. The plant Guiera senegalensis is used for traditional medicine among herb users in some parts of Nigeria. The leaves of the plant were extracted by serial exhaustive maceration using petroleum ether (PE), (600-800), Dichloromethane (DCM) and Methanol (MeOH). Thin layer chromatography of crude extract was carried out on both the crude and bioactive fractions of the extracts. The crude extract of PE prove to be sensitive on Escherichia coli and Pseudomonas aeruginosa showing significant zone of inhibition of about 14 mm and 21 mm respectively. Dichloromethane crude extract was sensitive only on Salmonella typhi while crude MeOH extract showed no activity against all the organisms. Column chromatography was carried out on PE and DCM extracts, using PE/ethyl acetate (4:1 v/v) and n-Hexane/ethyl acetate/DCM (4:1:1 v/v) eluents respectively. 17 fractions from PE extract and 19 fractions from DCM extract were collected. Thin layer chromatography (TLC), of the fractions group the PE and DCM into three each according to their retardation factor (Rf) values. The second fraction of the pet-ether fraction (P2), shows activity on all the test organisms except salmonella typhi. As for the DCM fractions, the first fraction (D1) was active against Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumonia, the second fraction (D2), against all the organisms used, while the third fraction (D3) was active only on Salmonella typhi and Pseudomonas aeruginosa. Phytochemical screening of the bioactive fractions, which was the aim of this study reveals the present of carbohydrate, steroids, saponins, flavonoids and alkaloids.