Anti-Streptomyces activity of Myrthus communis and Terminalia chebula, medicinal plants of south east regions of Iran

Streptomyces sp. are mostly soil-inhabitants and several species are responsible for important diseases in plants, S. scabies causal agent of Common Scab disease of potato and human S. somaliensis causal agent of Mycetoma. Methanolic extracts of leaves of Myrthus communis and seeds of Terminalia chebula, which had documented uses in Iranian herbal-medicine, were tested for anti-Streptomyces activity against S. scabies. For bioassays, concentration of 50 mg mL-1 of methanolic extracts prepared in dimethyl sulfoxide: methanol (v/v, 1/1) and tested in well diffusion method. Inhibitory zones (IZ) in contrast to controls were measured five days after inoculation at 29°C. Both plants showed high biological activity against S. scabies. Future goals include bioassays on human and further plant pathogenic Streptomycetes.