Effect of ethanol polarity and temperature on antioxidant activity, tyrosinase inhibition, and total phenol content of Garcinia atroviridis (Asam gelugor) fruits extract

บทคัดย่อ

In this study, the fruit of G. atroviridis was extracted and investigated their antioxidant activities and total phenolic content (TPC) using many extraction conditions, including temperature (10 ^oC, 25 ^oC, and 40^oC) and polarity of solvent (90%, 70%, and 50% w/w of ethanol). The extraction percentage yields were found in the range of 6.68 -18.97, depending on extraction temperatures and the polarity of solvents. The highest percentage yield of providing condition was at ethanol 40°C and 50% (w/w). Because of a different mechanism in assessing antioxidant capacity, antioxidant activities were performed using DPPH and ABTS techniques and reported as the percent inhibition. According to both techniques, the percent inhibition of crude extract was different in the range of 24.61–41.01 and 12.90–27.74 of DPPH and ABTS assay, respectively, depending on extraction temperatures and polarity solvents as well. The extract condition at 40°C and 50% (w/w) of ethanol provided the crude extract showing the highest antioxidant activity at percent inhibition of 41.01 ± 4.17 and 27.74 ± 0.84 for DPPH and ABTS assay, respectively. In addition, tyrosinase inhibition of crude extract displayed in the range of 42.88 – 56.13. The extracted temperature at 50°C and 50% (w/w) of ethanol provided the crude extract showing the highest tyrosinase inhibition at a percent inhibition of 46.13 ± 0.63. However, the extract temperatures used in this study did not affect the total phenolic content of crude extract, which was 13.39-17.41 mg GAE/g. The proper condition for extracting the crude G. atroviridis fruit was 50% ethanol as a solvent and 40 °C as an extraction temperature. The crude extract provided the highest yield, antioxidant capacity, tyrosinase inhibition, and total phenolic content from this condition.