Antioxidant and Tyrosinase Inhibitory Properties of an Aqueous Extract of Garcinia atroviridis Griff. ex. T. Anderson Fruit Pericarps

Background: Ultraviolet radiation (UVR) is the major cause for hyperpigmentation, and to prevent this natural products are increasingly being explored as potential skin whitening agents. The aim of this study was to determine the total phenolic and flavonoid content, free radical scavenging activity, anti-tyrosinase activity and the inhibition of melanin content in α-melanocyte stimulating hormone-induced B16F10 melanoma cells of an aqueous extract of Garcinia atroviridis Griff. ex. T. Anderson fruit pericarps. Methods: The aqueous extract was prepared by extraction with distilled water at 105oC for 60 min. Total phenolic and flavonoid content were determined using the Folin-Ciocalteau and aluminium chloride methods, respectively. Scavenging activity was assessed using 2,2-Diphennyl-1-picrylhydrazyl (DPPH) and 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS). Tyrosinase activity and melanin content were determined spectrophotometrically. Results: The results showed that the aqueous extract of Garcinia atroviridis fruit pericarps had a phenolic (26.33 ± 0.77 mg GAE/g plant extract) and flavonoid content (9.31 ± 0.40 mg QE/g plant extract). The aqueous extract of Garcinia atroviridis significantly inhibited mushroom tyrosinase activity (IC₅₀ of 40.72 ± 1.83 μg/mL) and cellular tyrosinase activity (at a concentration of 125 μg/mL) in α-melanocyte stimulating hormone-induced B16F10 melanoma cells. The Garcinia atroviridis extract also suppressed melanin content at concentrations of 31.25-125 μg/mL. Correlations of mushroom tyrosinase inhibition with DPPH and ABTS scavenging activities were 0.8673 and 0.9468, respectively. Conclusion: Our findings show that an aqueous extract of Garcinia atroviridis fruit pericarps is a source of natural compounds and antioxidant capacity which can inhibit tyrosinase activity and melanin content. Thus, aqueous extracts of Garcinia atroviridis may be a potential source of skin whitening agents for hyperpigmentation.