Antibacterial Screening of Selected Plants from Southwest USA in Search of Potential Natural Alternatives for Antibacterial Application

Author(s): Merhavy ZI, Varkey TC, Courtois EC, Varkey JA, De Bruyn G, Huls CE

The emergence of drug resistant microorganisms has posed important public health issues. The annual cost of treating antibiotic resistant infections in the United States alone has been estimated to be as high as $30 billion. This has led to an urgent need for new antimicrobial drugs, particularly from natural resources. Phytochemicals obtained from medicinal plants have been used widely in the development of novel therapeutics including antimicrobial agents. Therefore, it is imperative to detect substances which have inhibitory effects on the growth of bacterial species. This paper explores the efficacy of ethanol (80%) extracts of leaves of several plant species from southern Arizona that were screened for their antimicrobial efficacy against Staphylococcus epidermidis, Mycobacterium smegmatis, and Streptococcus mutans. Extracts were prepared by a maceration process and the antibacterial activity of different plants were evaluated and compared by measuring their zones of inhibition. Most notably, Lagerstroemia, Mahonia aquifolium, and Punica granatum expressed the highest antibacterial activity of the thirty-three (33) plant extracts tested.