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The present research is focused on the screening of antioxidant activities andtotal phenolic contents of intracellular and extracellular ethyl acetate crude extracts ofsix actinomycetes isolated from soil sample collected at the coastal and mangroveregions in Chonburi, Chantaburi and Nakhon Si Thammarat provinces. The extractedsamples (A16-1, CH54-5, CH54-8, PL3-6, PL4-6 and PL7-4) were evaluated forantioxidant activities with TLC-DPPH, DPPH radical scavenging assay, ABTSradical scavenging assay and total phenolic contents. The results showed that theextracellular extracts have higher antioxidant activities as compared to those ofintracellular extracts which measured by DPPH and ABTS assay. The DPPH andABTS radical scavenging activities of the extracellular extracts were observed with anIC50 in a range of 50.62+0.36 –196.83+3.55 and 15.46+2.57 – 98.48+3.3 μg/mL,respectively. The isolate PL3-6 and PL7-4 showed the highest DPPH activity at IC50value of 50.62+0.36 μg/mL and 51.5+0.75 μg/mL respectively whereas CH54-5displayed the strongest ABTS activity with an IC50 value of 15.46+2.57 μg/mL. Incase of the intracellular extracts, the isolate CH54-8 showed the moderate DPPH andABTS activities with an IC50 value of 269.12+15.37 and 99.15+0.99 μg/mL,respectively. The total phenolic contents (TPC) of the extracellular extracts rangefrom 81.31+5.37 – 210.99+21.21 mgGAE/g dried weight. The results showed that thehighest amount of total phenolic contents was found in isolate CH54-8 at the value of210.99+21.21 mgGAE/g dried weight.