Tyrosinase Modulation and Antioxidant Activity of Jordanian Rhus coriaria L. Fruit Extract

Abstract

Background: Tyrosinase is an enzyme involved in the melanin synthesis. Hyperactive tyrosinase leads to hyperpigmentation diseases such as melasma, lentigo, and post-inflammatory hyperpigmentation. Sumac (Rhus coriaria L.) is an antioxidant fruit abundant in phenolic compounds, which is native to the Levantine area. Aim: To evaluate the potential antibacterial, antioxidant, and anti-tyrosinase activity of sumac fruit extract, and to quantify total phenolic and flavonoid content. Methods: Methanolic extract was prepared, and the antibacterial effect was determined by the agar well diffusion method and by Minimal Inhibitory Concentration (MIC). The anticancer effect was tested on glioblastoma U-87 cells by MTT assay. Antioxidant activity was quantified by Diphenyl-Picrylhydrazyl (DPPH) assay. Antityrosinase activity was evaluated by Mushroom Tyrosinase activity enzymatic assay. Finally, total flavonoids and phenolic content were measured using the colourimetric method. Results: Phytochemical analysis showed good concentrations of phenolic compounds (14.3±0.44) mg GAE /100Mg and flavonoids (1.71±0.17) mg catechin/100 mg dried extract; a good antibacterial activity against Escherichia coli (0.0625 mg/ml), S. aureus (0.25 mg/ml) and S. agalactiae (0.25 mg/ml). A remarkable DPPH scavenging activity IC50 of 17 µcg/ml. Furthermore, tyrosinase activity with 87.24% inhibition at 1mg concentration and an IC50 of 17 µg/ml whereas kojac acid IC50 of 9.3 µg/ml. MTT assay were % survival was significantly reduced at 5 and 50 ug/ml to 72%, 65.8 % respectively. Conclusion: Sumac fruit extract is a potential source of active compounds that can be used as antibacterial, antioxidant, antityrosinase, and anticancer agents due to its richness in phenolic compounds and alkaloids, supporting its use in cosmeceutical and pharmaceutical formulations. Major Findings: Jordanian R. coriaria L. demonstrated potent tyrosinase inhibition (IC50 = 17 µg/ml), markedly superior to arbutin (IC50 = 92.5 µg/ml), alongside strong antioxidant (IC50 = 17 µg/ml) and antibacterial activities, highlighting its promise as a plant-derived candidate for hyperpigmentation management.