Assessment of actinomycetes isolated from soils on Simeuleu Island as antibacterial and antioxidant

The study was conducted to determine the potential of ethyl acetate extracts of Actinomycetes isolated from soil in Simeuleu Island. A total of 51 Actinomycetes extracts were tested for their potential as an antibacterial against S. aureus InaCC-B4 and E. coli InaCC-B5 as well as their activities as an antioxidant. The antibacterial and antioxidant as DPPH- free radical scavengers assays were carried out by thin layer bioautography (TLC) method, and the determination of the minimum inhibitory concentration (MIC) and IC50values was carried out by serial dilution method in 96 microwell plate. Bioautography results showed the number of extracts capable of inhibiting S. aureus, and E. coli were 50 and 28 extracts, respectively. There were 20 extracts had antioxidant activity. The results also showed that three extracts could be classified as strong bacterial activity against S. aureus, i.e., TN01-07, TN01-15 and TN01-24; three extracts had strong antibacterial activity against E. coli, i.e., TN01-13, TN01 -25, TN01-27 and one extract (TN01-17) had strong antioxidant activity. Actinomycetes isolated from soil from Simueleu Island were promising sources as antibacterial and antioxidant.