การผลิตสารต้านออกซิเดชันโดยแอคติโนแบคทีเรียหายากบางชนิด

Abstract

Oxidative stress represents an imbalance between the production of reactive oxygen species (ROS) which causes oxidative damage to protein, lipids and DNA. Rare actinobacteria are considered as promising sources of the chemically diverse secondary metabolites and novel biological activities. In this study, ten rare actinobacteria were screened for their antioxidant activity using three culture media; international Streptomyces project medium-2 (ISP2), glucose yeast extract (GYE) and tryptic soy broth (TSB). Dermacoccus nishinomiyaensis DSM20448T, D. abyssi MT1.1'and Tsukamurella sp. MT6.7 growth in glucose yeast extract (GYE) and tryptic soy broth (TSB) showed high total phenolic compound and the antioxidant activity when compared with other media and strains. Therefore, these three actinobacteria were chosen for investigation of optimal fermentation condition. Under optimal fermentation condition, the total phenolic content was increased 2.91-7.99% and free radical scavenging activity based on ABTS, DPPH and FRAP assay as trolox and ascorbic acid standard were increased 8.05- 71.79%, 2.66-10.79% and 12.93 -42.55 %, respectively. The GC-MS analysis of ethyl acetate extracts from 10 actinobacteria revealed the presence of phenol, uric acid, d-proline, vanillin, arsinecarbonitrile, arsenous acid, delta.2-Tetrazaboroline, tris(trimethylsilyl) ester, 2,6-dihydroxyacetophenone, 1,2,4- benzenetriol benzofuroxan and 3-ethoxy-4-methoxyphenol are present with antioxidant activity. In addition, the gallic acid was measured by high performance liquid chromatography (HPLC) and the highest gallic acid was detected in Modestobacter caceresii KNN 45-2bT at 0.836 g/L