Antimicrobial activity and safety of two medicinal plants traditionally used in bomet district of Kenya

Abstract

Indigenous rural communities in the tropics manage microbial diseases using herbal concoctions. The efficacy and safety of most of the herbal preparations have not been proven scientifically. Extracts from two selected plant species were evaluated for in vitro antimicrobial activities and toxicity. Extraction was done using hexane, dichloromethane, methanol and water. Hexane extracts of Senna didymobotrya was active against Microsporum gypseum with 16.0 mm inhibition zone diameters and no activity against other test isolates. Dichloromethane extracts had good activities against Trichophyton mentagrophyte and Microsporum gypseum with 18.0 and 15.0 mm inhibition zones, respectively. Minimum inhibition concentration of Cyathulapolycephala extracts against bacterial isolates ranged from 25.0 to 3.124 mg mL -1. Methanol extracts of C. polycephala had a CC 50 of 100.0%. The water extracts recorded CC 50 of 23.75 and 31.56% at 1000 and 100 mg mL -1 concentration, respectively. The methanol extracts recorded a CC 50 of 99.34 and 100.0% at 1000 and 100 mg mL -1 concentration, respectively. The DCM extract of S. didymobotrya was very toxic at 5000 mg kg -1 and killed 80% of mice. In both the cell and acute toxicity, it was observed that extracts at high concentration and at a high dose tend to be toxic. Most extracts were active against a wide range of bacteria than fungi. © 2012 Academic Journals Inc.