Antimicrobial activity of some medicinal plant extracts

In this study, the alcoholic and lyophilized aqueous extracts from 20 wild medicinal plants belonging to two families from the Al-Qassim area were studied. The sensitivity of 18 microbes [5 Gram-positive and 6 Gram-negative bacteria, 5 fungi and 2 yeasts] to the prepared extracts at concentrations of 10, 25, 50, 100 and 200 mg/ml was investigated. The minimum inhibitory concentrations [MIC] for different active extracts were also investigated against the tested bacteria. Alcoholic and aqueous extracts of the studied plants exhibited a strong antibacterial activity against Staph. aureus, Staph. aureus [methicillin resistant], Strept. types B and D, Salm. type C, E. coli, H. influenza, Pr. mirabilis and Ps. aeruginosa. The values of MIC for C. bruguierana, R. stricta, P. harmala, C. coccineum [No. 6] and W. somnifera extracts against H. influenza were 8.36, 8.42, 8.47, 23.77 and 23.87 mg/ml, respectively. It was also observed that fungi and yeasts were less sensitive, with the exception of T. mentagrophytes which was slightly sensitive to some plant extracts