In vitro pharmacological evaluation of three Barleria species.

ETHNOPHARMACOLOGICAL RELEVANCE: Various parts of Barleria prionitis L. (Acanthaceae) are used in traditional medicine to treat infection-related ailments. A comparison of their activities and knowledge of their mechanisms of action are important for drug development and conservation.

AIMS OF THE STUDY: This study investigated the antibacterial effects and underlying mechanisms of action of the anti-inflammatory activities of different parts of three Barleria species of South African origin.

MATERIALS AND METHODS: Crude extracts of different parts of three Barleria species were investigated in vitro for their biological activity. Antibacterial activity was evaluated using the micro-dilution assay against two Gram-positive and two Gram-negative bacteria. Anti-inflammatory activity was evaluated using the cyclooxygenase COX-1 and COX-2 assays.

RESULTS: All the extracts showed broad-spectrum antibacterial activity with minimum inhibitory concentrations ranging from 0.059 to 6.25mg/ml. Twelve out of 21 crude extracts evaluated showed good activity (>70%) in the COX-1 assay while 10 extracts showed good activity in the COX-2 assay. All the petroleum ether extracts (except B. prionitis stem) exhibited good inhibition of prostaglandin synthesis in COX-1.

CONCLUSION: The results demonstrated the therapeutic potential of these plants as antibacterial and anti-inflammatory agents. Their anti-inflammatory properties are mediated by the inhibition of the cyclooxygenase enzymes.