Antimicrobial Potency against Microbes Found in Clinical Samples and Toxicity Studies on Selected Medicinal Plants

The antibacterial and antifungal activities of Terminalia arjuna, Tephrosia purpurea and Thuja occidentalis extracts were investigated against the standard drugs, which are presently available in the market as Gentamicin, Cephradine, Amoxicillin clavulanate, Norfloxacin and Itraconazole. Well method was used for antimicrobial activity and the zones of inhibition were measured in millimeters. The antibacterial activity was observed on three gram negative bacteria i.e. Escherichia coli, Klebsiella pneumonia and Pseudomonas aeruginosa and one gram positive bacteria i.e. Staphylococcus aureus. The antifungal activity was investigated against Candida albicans and Aspergillus niger. The cytotoxic effects (LD50) of the crude extracts were also observed on brine shrimps (Artemia salina) using Etoposide as an internal standard. The crude extract of T. arjuna bark exhibited less potent antimicrobial activity as compared to crude extract of T. arjuna heart wood. Bark extract of T. arjuna showed no cytotoxic activity but heart wood extract showed this activity in brine shrimp bioassay technique. The crude extract of T. purpurea showed positive cytotoxic, potent antibacterial but no antifungal activity. The crude extract of T. occidentalis showed good antibacterial low antifungal and low cytotoxic activity. T. arjuna showed most potent antimicrobial and cytotoxic activity while T. Purpurea and T. oocidentalis posses less potent activities.