Background: Actinobacteria usually produce different functional compounds for various applications.
Objective: The aim of this research was to develop actinobacterial resources through the isolation and identification of soil bacteria with antibacterial and enzyme inhibitory activities for cosmetics application.
Methods: Soil bacteria were isolated and tested for antibacterial activity against Propionibacterium acnes and Staphylococcus epidermidis using the spotting method. Isolates exhibiting antibacterial activities were assayed for tyrosinase inhibition, elastase inhibition, and free radical scavenging activity.
Results: Twelve actinobacterial strains were found to inhibit the growth of P. acnes and S. epidermidis. Among them, ten were from the genus Streptomyces and the other two were from the genera Actinokineospora and Calidifontibacter, and potentially represented novel species. For tyrosinase inhibition activities, when compared with arbutin (IC50 =47.84±0.36 μg mL-1 ), strain T65 had similar activity with an IC50 value of 49.05±3.29 μg mL-1 . For elastase inhibition, strains T65, T811, and R311 had similar activities with IC50 values of 10.78±1.88 μg mL-1 , 10.19±0.82 μg mL-1 , and 10.19±2.1 μg mL-1 , respectively, which had similar inhibitory activity to the IC50 value of the standard oleanolic acid (8.94±1.38 μg mL-1 ). For DPPH radical scavenging activities, two strains, R311 and T327, with IC50 values of 6.11±1.17 μg mL-1 and 5.25±0.93 μg mL-1 , respectively, had slightly lower activities than ascorbic acid (IC50 =4.08±0.03 μg mL-1 ).
Conclusion: Among twelve strains of actinobacteria, the most effective strains were selected for the inhibition of both P. acnes and S. epidermidis as well as for enzyme activities. Actinobacterial strains isolated in this study could be used to produce active metabolites for cosmetics applications.
Keywords: DPPH; Propionibacterium acnes; actinobacterial resources; functional cosmetics; tyrosinase.
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