Evaluation of anti-melanogenic activity of Ziziphus jujuba fruits obtained by two different extraction methods

Abstract

Background and objectives: Dried pulps and peels of Ziziphus jujuba fruits are commonly applied as food because of their high nutritional value. It has been widely used in traditional medicine as laxative, tonic, wound healing agent and appetizer. The aim of this study was to evaluate the anti-melanogenic effects of Z. jujuba fruit. Methods: Fruit extracts were obtained by two different extraction methods, percolation (cold extraction) and soxhlet (hot extraction) using methanol 80% as the solvent. The total phenolic and flavonoid contents, DPPH radical scavenging activity and anti-tyrosinase capacity of the MeOH extracts from Z. jujuba fruits were evaluated in vitro. In addition, the effects of fruit extracts on the melanin content and cytotoxicity on human melanoma SKMEL-3 cells were determined after 72 hours. Results: The amount of total phenolic and flavonoid contents of the cold extract were found higher in comparison to the hot extract. Moreover, the antioxidant (SC50 =1.40 mg/mL) and anti-tyrosinase activities (IC50 = 0.54 mg/mL) of the cold extract were significantly stronger than the hot extract. At the dose of 500 μg/mL, the cold extract showed weaker toxicity to the melanoma cells than the hot extract. Melanin content of the cold extract was reduced to 30% at this concentration, while the hot extract had no inhibitory effect on melanin formation. Conclusion: The results showed that the percolation method was more suitable for extraction of the (poly) phenolics from Z. jujuba fruits. In addition, the results of tyrosinase activity and melanin content assays suggested that the cold extract of Z. jujuba fruit can be considered as a dermatological whitening agent in skin care products.

Keywords

• anti-tyrosinase
• cytotoxicity
• DPPH
• melanin
• Ziziphus jujuba