Screening of medicinal plants from Trinidad and Tobago for antimicrobial and insecticidal properties.

Antibacterial activity in 51 extracts from 29 plant species currently used in traditional medicine in Trinidad and the neighbouring Caribbean islands was tested for by the agar dilution streak method using six bacteria: Escherichia coli, Pseudomonas aeruginosa. Salmonella tophimurium, Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis. The extracts from eight of the plants tested showed significant activity against one or more micro-organisms and the most susceptible bacterium was Staphylococcus aureus. In the bioassays for toxicity towards the Aedes aegypti mosquito the most effective plant extracts were from Justicia pectoralis, Manihot utilissima and Stachytarpheta jamaicensis.