Antibiotic activity and anticancer potential of a new Nonomuraea sp. Strain PT708 originated from Thai cave soil

Abstract

© 2012 by World Scientific Publishing Co. Pte. Ltd. All rights reserved. Strain PT708 was isolated from cave soil at Pha Tup Cave Forest Park, Nan Province, Thailand. Phylogenetic analysis indicated that it belongs to the genus Nonomuraea, with a relatively high similarity value (98.28%) to the 16S rRNA gene sequence to Nonomuraea roseola AJ278221 and Nonomuraea dietziae AJ278220. However, its unique morphology, forming a single spore at the end of branched mycelium, is different with those species of the genus Nonomuraea. Consequently, we propose that the strain should be assigned to a new species in this genus. Strain PT708 showed ability to produce antimicrobial compounds against Bacillus cereus, methicillin-resistant Staphylococcus aureus (MRSA) and Paenibacillus larvae when it was grown in AMHU-5 medium. MRSA and B. cereus are the most susceptible strains, with equal MIC values of 80 µg/mL followed by P. larvae with MIC value of 175 µg/mL. Moreover, a crude extract from this strain showed anticancer activities against human small cell lung cancer (NCI-H187) and human oral cavity cancer (KB) with IC50 values of 3.48 and 16.11 µg/mL, respectively, but no inhibition was observed for human breast cancer (MCF7) with concentration up to 50 µg/mL.