Antimicrobial activity of South African Podocarpus species

Several species of Podocarpus (Podocarpaceae) are utilized in treating ailments across the world. In Africa, four species are used traditionally in both animal and human health. To investigate the antimicrobial activity of Podocarpus species against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Candida albicans. Six solvents of varying polarity were used for extraction. Antibacterial activity was assessed using the microdilution bioassay and for antifungal activity, the microdilution bioassay and (M27-P) broth dilution were used. All species exhibited antimicrobial activity with MIC values of less than 1 mg/ml. Inhibition against Gram-positive bacteria was stronger with an MIC value of 98 μg/ml while for Gram-negative bacteria, the highest inhibition was against Klebsiella pneumoniae with an MIC value of 0.33 mg/ml. All species exhibited strong antifungal activity with the best MIC being 30 μg/ml after 48 h. All four species exhibited strong inhibition against all tested microbials, based on Aligiannis et al. [Aligiannis, N., Kalpotzakis, E., Mitaku, S., Chinou, I.B., 2001. Composition and antimicrobial activity of the essential oils of two Origanum species. Journal of Agricultural and Food Chemistry 40, 4168–4170] classification they can be classified as strong inhibitors.