INVITRO ANTIMICROBIAL ACTIVITIES OF LEAF EXTRACTS OF FIVE INDIGENOUS MEDICINAL TREE SPECIES FROM SEMI ARID REGIONS OF KATTAKADA, KERALA, INDIA.

The present study reports the antimicrobial potential of 15 ethanol leaf extracts derived from commonly occurring five native medicinal tree species belonging to different families collected from the semi- arid regions of Kattakada, Kerala, India. The plants selected for the study were Annonasquamosa, Thespesiapopulnea, Murrayakoenigii, Glyricidiasepium and Moringaoleifera .Antimicrobial potential of these tree species were screened in vitro by the agar cup plate assay method against two bacterial and fungal isolates. Antibacterial activity was evaluated against two selected gram negative pathogens (Escherichia coli and Pseudomonas aeroginosa) whereas antifungal activity against two clinical fungal isolates (Candida albicans and Aspergillusniger). Among the varying concentration of leaf extracts, higher concentration exhibited maximum antimicrobial activity against the isolates. Antifungal activity were found to be low when compared to antibacterial activity. Highest antibacterial activity against P.aeriginosaand E.coli was exhibited by the leaf extracts of Moringaoleiferaand lowest by Murrayakoenigii . Whereas Thespesiapopulnea and Glyricidiasepium did not exhibit any antifungal activity. The results suggest that the leaves are a rich source of valuable primary and secondary metabolites which could be further exploited for the isolation and identification of active principle and for the evaluation of possible antimicrobial activity of other extracts from other parts of these tree species.