In Vitro Antimicrobial Activity of Fruit Extracts against Microbial Pathogens Causing Infections in Human and Animals.

Long pepper ( Vahl) is a Thai medicinal herb which has been used as one of the common ingredients in variety of Thai foods. Here, we investigated antimicrobial activities of crude bioactive metabolites extracted from fruits of against 10 pathogenic organisms (bacteria and yeast) causing opportunistic infections in human or animals including ATCC6633, ATCC25923, ATCC2921, ATCC25922, TISTR1843, ATCC741, (clinical isolate), (XN98 and 5HP), and ATCC90020. The results of disk diffusion test showed that the extract from methanol solvent exhibited greater antibacterial activity than other solvents with inhibition zones ranging from 0.5 to 8.0 mm, respectively. Subsequently, minimal inhibition concentration (MIC) determined by the colorimetric assay confirmed that methanol extracts showed consistent results with disk diffusion method. In summary, assays suggest that methanol is the best solvent for extraction of bioactive metabolites from fruits. This crude extract can inhibit the majority of human and animal pathogens. This opens up a potential use of pepper fruits in prevention of food-contaminating microorganisms.