Antidiabetic, dermatoprotective, antioxidant and chemical functionalities in Zizyphus lotus leaves and fruits

Medicinal plants provide important sources of new chemical substances with potential therapeutic effects. They have been used in traditional medicine for the treatment of several diseases. The present study investigated the antidiabetic (anti-amylase and anti-glucosidase) and dermatoprotective (anti-tyrosinase) activities of Zizyphus lotus (Rhamnaceae) leaves and fruits. This plant is known for several medicinal applications; the phenolic profile of aqueous extracts of Z. lotus was also developed using HPLC-DAD-QTOF-MS analysis. The chemical analysis resulted in the identification and quantification of twenty phenolic compounds in the fruits and/or leaves. Zizyphus lotus was highly dosed in gallic acid with 2715 mg/kg in leaves and 15,640 mg/kg in fruits. Z. lotus leaves and fruits, demonstrated inhibitory effects against α-amylase (IC 50 : 20.40–31.91 μg/mL), and α-glucosidase (IC 50 : 8.66–27.95 μg/mL). In tyrosinase inhibition, the fruits exhibited a higher effect (70.23 μg/mL) than the leaves. Furthermore, the extracts did show interesting antioxidant activity; thus Z. lotus constitutes a promising traditional medicine and this study contributed to identify some functional compounds responsible for its bioactivity.