Antimicrobial evaluation and phytochemical screening of aqueous and dichloromethane crude extracts in Kenya Physalis Peruviana L

Abstract

Physalis peruviana L a plant in Solanaceae family is used in folklore traditional medicine for treatment of bacterial, fungal and viral protozoal diseases. In this study aqueous and dichloromethane Physalis peruviana L extracts were evaluated for antimicrobial activity against some common bacterial and fungal isolates. The agar disc diffusion method was carried out to test antimicrobial activity against Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 11778, Escherichia coli ATCC 25922, Klebsiella pneumonia local isolate, Salmonella typhi ATCC 700931, Pseudomonas aeroginosa ATCC 27853, Candida albicans ATCC 90028 and Aspergillus flavus local isolate). All the plant extracts were also examined for Phytochemical components. Partial characterization of antimicrobial activity of the most active extract (dichloromethane leaf extracts) at 250 mg/ml was carried out at different pH and temperature ranges. The results on phytochemical screening demonstrated the presence of tannins, saponins, steroids, flavonoids, while anthraquinone was lacking in all extracts. Most of the plant extracts (87.5%) exhibited various inhibitory effects to test microbes while only a few (12.5%) did not show any antimicrobial activity. Statistical analysis for intra-group inhibitory activity amongst various extract concentrations demonstrated significant differences (P<0.01). The MIC and MMC of the various plant extracts ranged from 3.9 mg/ml to 62.5 mg/ml. The increase in pH and temperature led to a decrease and an increase in antimicrobial activity respectively. These results indicate that all plant parts of P. peruviana could be potential sources of antimicrobial agents with dichloromethane leave extracts being the most potent.