Isolation of endophytic actinomycetes from Catharanthes roseus (L.) G. Don leaves and their antimicrobial activity

Endophytic actinomycetes were isolated from surface sterilized leaves of Catharanthes roseus (L.) G. Don of family Apocynaceae. A total of 38 endophytic actinomycetes were recovered on Starch Casein Agar. Among the 38 isolates 20 morphologically different isolates were screened for antibacterial activity against Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, Proteus vulgaris and for antifungal activity against fungi Candida albicans, Botrytis cinerea, Curvularia lunata, Fusarium oxysporum, Fusarium solani and Rhizoctonia solani. Sixty five percent of the isolates exhibited antimicrobial activity. Among the 20 isolates tested two isolates Cr-12, Cr-20 exhibited highest activity against the test organisms. The selective isolation of endophytic actinomycetes in the present study indicates the richness of microbial diversity in Catharanthus roseus and screening for antimicrobial activity should be investigated for a comprehensive identification and potential use as source of bioactive agents.