Exploring the Potential of Morus nigra L. Fruit and Leaves as Food Additives: Antioxidant, Antiproliferative, Enzyme Inhibition Effects, and Phytochemical Profiles

ABSTRACT Morus nigra has been used in folk medicine and as food since ancient times. In this study, the cytotoxic, antioxidant, urease enzyme, and enzymatic browning inhibitory effects of the fruits and pruning by‐product leaves were investigated, and their potential as food additives was evaluated. LC–MS/MS analysis showed that quinic acid (48.904 mg/g extract) was present in the highest amount in the fruit, while isoquercitrin (20.38 mg/g extract) was present in the highest amount in the leaves. According to the MTT method, the leaf ethyl acetate fraction (LEF) showed the highest cytotoxic effect against Hep‐3B cells at 400 µg/mL with 48.20% cell viability. The antioxidant capacity of LEF is approximately three times that of Trolox and half that of gallic acid. LEF inhibited urease with IC 50 : 23.42 ± 2.02 µg/mL and tyrosinase with IC 50 : 22.88 ± 1.02 µg/mL. With its potent biological effects, M. nigra could be a promising resource for the food industry.