Piper genus: source of natural products with anti-tyrosinase activity favored in phytocosmetics

Abstract

Tyrosinase is an enzyme part of the melanogenic cycle, which provides color to skin, hair and eyes; when present in high concentrations it produces hyperpigmentation. The aim of this study was to determine tyrosinase inhibitory activity of extracts (dichloromethane and methanol) from ten Guatemalan species of the genus Piper (P. amalago, P. auritum, P. hispidum, P. jacquemontianum, P. oradendron, P. psilorhachis, P. retalhuleuense, P. sempervirens, P. umbellatum and P. variabile). The inhibitory effect of tyrosinase activity was determined by enzymatic assays, qualitative thin layer chromatography (TLC) and quantitative by spetrophotometric kinetic method. Samples were analyzed in quintuplicate and reference standard solutions of kojic acid were used to verify the effectiveness of the tests, being all statistically significant at a confidence interval of 95%. All the extracts demonstrated some degree of inhibition by the bioautographic procedure, in four extracts activity has been confirmed by quantitative spectrophotometry. Extracts with the best inhibition activity in both solvents were P. variabile (IC50 2.0±0.1 μg/mL) and P. umbellatum (IC50 4.9±0.2 μg/mL); and, methanol extract of P. jacquemontianum (IC50 6.8±0.3 μg/mL) and P. psilorhachis (IC50 6.5±0.3 μg/mL). Kojic acid activity was higher than Piper extracts, but the analyzed extracts deserve further evaluation.