IDENTIFICATION AND ANTIMICROBIAL ACTIVITY OF ENDOPHYTIC ACTINOMYCETES ISOLATED FROM MEDICINAL PLANTS IN THAILAND

Abstract

Forty-seven actinomycetes were isolated from leaves, stems and roots of seven medicinal plants, Catharanthus roseus, Stemona sp., Phyllanthus amarus, Pseuderanthemum graciliflorum, Phyllanthuspulcher, Vernoniacinerea and Ophiorrhiza sp. by using starch-casein, humic acid-vitamin and water agar. They were identified as Streptomyces (14 isolates), Amycolatopsis (1 isolate), Nocardia (5 isolates), Micromonospora (6 isolates), Microbispora (15 isolates) and Nonomuraea (6 isolates) based on phenotypic and genotypic characteristics. On the basis of 16S rRNA gene sequences analysis, Streptomyces (2 isolates), PA1-07 was similar to Streptomyces curacoi JCM 4219T (98.75%) while VC1-01 was similar to S. coelurescens JCM 4360T (99.04%). Amycolatopsis (1 isolate), ST1-08 was similar to Amycolatopsis pretoriensis JCM 12673T (99.17%). Nocardia (1 isolate), ST1-06 was similar to Nocardia araoensis JCM 12118T (99.03%). Microbispora (7 isolates), CR1-01, CR1-04, CR1-07, CR1-08 and CR1-11 were similar to Microbispora rosea subsp. rosea JCM 3006T (98.83-99.17%) while CR1-09 was similar to M. hainanensis JCM 19666T (98.98-99.93%) and OH1-01 was similar to M. corallina JCM 10267T (98.96%). Nonomuraea (1 isolate), PA1-10 was similar to Nonomuraea candida JCM 15928T (98.31%). The ethyl acetate extract of these isolates were screened for antimicrobial activity based on disc diffusion method. The crude extract of CR1-01 and CR1-08 showed antibacterial activity against Staphylococcus aureus ATCC 6538. The crude extract of CR1-01 and CR1-05 showed against Kocuria rhizophila ATCC 9341. Whereas, the crude extract of ST1-02 and ST1-05 exhibited against Candida albicans ATCC 10231.