Abstract

Extracts of leaves, stem bark, roots and fruits of Solanum macranthum Dunal were subjected to preliminary phytochemical screening for the presence of plant secondary metabolites and in vitro antibacterial and antifungal studies respectively. The results of the preliminary investigation revealed the presence of alkaloids, the steroidal nucleus, saponins, tannins, cardiac glycosides, flavonoids, reducing sugars and anthraquinones. The in vitro antimicrobial activity was done using agar well diffusion technique. Six clinical strains of human pathogenic microorganisms, comprising two Gram positive, two Gram negative bacteria and two fungi were utilized in the studies. The various plant extracts varied in their high inhibitory activity to Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli at 1000 mg/ml comparable to the reference antibacterial drug, gentamicin at 2.5 mg/ml. High activity was exhibited against Bacillus subtilis whilst Candida albicans and Aspergillus niger were moderately inhibited even at 2000 mg/ml.

Key words: Solanum macranthum, Solanaceae, antimicrobial activity, phytochemical screening.