Abstract
Context: Litchi chinensis Sonn. (Spindaceae) is an important economic fruit of Thailand. Therapeutic effects of the fruits are contributed by anti-inflammatory phenolics. Objective: To extract the litchi fruit pericarp in order to identify biologically actives substances with potential for cosmetic application. Materials and methods: The litchi pericarp was macerated by 70% ethanol (EtOH) and partitioned using n-hexane and ethyl acetate (EtOAc). In vitro antioxidant activities were assessed by 1, 1-diphenyl-2-picrylhydrazyl (DPPH), ABTS and ferric reducing ability of plasma (FRAP) assays including tyrosinase inhibitory effect. Cellular radical scavenging capacity was monitored in a normal human fibroblast cell culture (NHF). Total phenolic content was determined and characterized by HPLC. Results: The EtOAc fraction was a significant antioxidant, stronger than ascorbic acid (p < 0.01), as assessed by ABTS (IC50 = 7.137 +/- 0.021 mu g/mL), DPPH (IC50 = 2.288 +/- 0.063 mu g/mL) and FRAP (EC1mMFeSO4 = 8013.183 +/- 58.804 mu g/mL) assays. It demonstrated an antityrosinase effect (IC50 = 197.860 +/- 1.230 mu g/mL) and showed no cytotoxic activity toward Vero and NHF cells, at a maximum tested concentration (50 mu g/mL), with cellular antioxidant activity. Total phenolic content was highest in the most potent antioxidant fraction. Quercetin, rosmarinic and gallic acids were found. Total phenolic content is highly related to FRAP, antityrosinase, and ABTS activities. Discussion and conclusion: Pericarp from litchi fruit can be obtained abundantly from agricultural waste, and the strong antioxidant activity demonstrated in this report may have application in topical cosmetic products. This ecological antioxidant can be prepared using a feasible method resulting in less waste and increased agro-industrial profitability.
