Azadirachta indica (Neem) Water Leaf Extract Inhibits Melanin Production and Tyrosinase Activity in B16F10 Melanoma Cells

Introduction: Abnormal melanin production can cause pigmentary disorder such as hyperpigmentation. Finding a potent medicinal plants that can prevent pigment disorder. Objective: This study was to investigate the potential of leaf extract from Azadirachta indica var siamensis valeton to inhibit melanin formation or melanogenesis. Materials and Methods: A.indica leaf extract was tested for phenolic and flavonoid content assay. Tests using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay were administered to determine the toxicity of A.indica leaf extract in B16F10 melanoma cells. Melanin content and tyrosinase activity assays were used to determine the potential for the inhibition of melanogenesis. Data was analyzed using SPSS. Results: It was found that A.indica leaf extract per gram has a total phenolic content of 28.73 ± 0.30 mg gallic acid equivalents and flavonoid of 12.48 ± 0.00 mg rutin equivalent. In addition, we found that these herbal extracts decreased the melanin content and intracellular tyrosinase activity in B16F10 melanoma cells without any toxicity. This study suggested that the melanin content and intracellular tyrosinase activity in B16F10 melanoma cells were decreased without any cytotoxicity by the A.indica leaf water extract. Conclusion: The findings demonstrated that A.indica leaf water extract inhibits melanin production through reducing tyrosinase activity. These results could be useful as a therapeutic treatment for skin hyperpigmentation disorders as well as an effective ingredient in whitening cosmetics.