Antioxidant Activity, Tyrosinase Inhibition Activity, Total Phenolic Content and Total Flavonoid Content of Crude Extracts of Fruit and Leaf of Terminalia chebula Retz.

Abstract

This research aimed to determine the antioxidant activity, tyrosinase inhibition activity, total phenolic content and total flavonoid content of crude extracts of fruit and leaf of Terminalia chebula Retz. The extracts were prepared by using three different solvents including 95% ethanol, 70% ethanol, and 50% ethanol. The antioxidant activity was determined by using 2,2-diphenyl-1-picrylhydrazyl radial scavenging capacity assay (DPPH assay), ABTS radical cation decolorization assay (ABTS assay) and ferric ion reducing antioxidant power (FRAP) assay. The tyrosinase inhibition activity was determined by using the Dopachrome method. Total phenolic content was analyzed by the Folin-Ciocalteu assay and total flavonoid content was analyzed by the Aluminum chloride colorimetric assay. From the results, it was found that the crude 95% ethanol extract of Terminalia chebula Retz. leaf exhibited the most potent antioxidant activity determined by DPPH assay (IC₅₀ = 8.064±0.19 µg/mL) and by FRAP assay (FRAP value = 1,238.211±2.47 mM FeSO₄ equivalent/g extract). Moreover, it exhibited the strongest tyrosinase inhibition activity (IC₅₀ = 0.327±0.10 mg/mL) and the highest total flavonoid content (144.183 ± 6.73 mg quercetin equivalent/g extract). On the other hand, the crude 50% ethanol extract of Terminalia chebula Retz. leaf exhibited the highest antioxidant activity determined by ABTS assay with the ABTS^•+ scavenging activity of 442.405±12.16 mg ascorbic acid equivalent/g extract and the highest phenolic content (418.007±19.55 mg gallic acid equivalent/g extract). This research demonstrates that Terminalia chebula Retz. leaf is considered to be an interesting source of bioactive compounds. It may be an alternative herb for cosmetic applications and further research in pharmacology for the development of active drug compounds.