Morus alba L. and Morus nigra L. Leaves as a Promising Food Source of Phenolic Compounds with Antioxidant Activity

Bioactivity of mulberry has been widely described, but mostly related to its fruits, while studies with leaves are scarce. Herein, in this study leaves of two mulberry species (Morus alba L. and Morus nigra L.) were characterized, compared, and evaluated in terms of their phenolic composition and antioxidant activity. Aiming to valorize mulberry leaves extracts which can be included in modern diet four different extracts (infusions, decoctions, tinctures and hydromethanolic) were examined. The chemical characterization was done by quantifying total phenolics (TPC), flavonoids (TFC) and phenolic acids (TPAC) content, L( +)ascorbic acid (ASA) and individual phenolic compounds in the extracts by HPLC technique. Moreover, DPPH and FRAP assays were used to assess the antioxidant activity of white and black mulberry leaves. Findings of these studies revealed that black mulberry leaves were richer in TFC and TPAC, while white mulberry leaves contained higher levels of individual phenolic compounds in water extracts. Gallic acid was found in the highest concentrations in two mulberry leave extracts. Correlation analysis showed strong relationships between antioxidant activity and TPC and TFC. This fact suggests the crucial role of phenolic compounds as antioxidant agents in white and black mulberry leaves. The results obtained in this study demonstrate that leaves of both white and black mulberry can be used as a valuable source of phenolic compounds with bioactive potential, which can be applied in the food sector, as foods and as promising source of natural ingredients. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11130-021-00922-7.