Antioxidant and antityrosinase activity of mulberry (Morus alba L.) twigs and root bark

The antioxidant and antityrosinase activities of the ethanolic extract of mulberry twigs (EEMT) were investigated. The results showed that EEMT exhibited radical scavenging and reducing activity, as well as ferrous ion-chelating activity. In addition, EEMT also protected phospholipids against free radicals, indicating that EEMT could protect biomolecules from oxidative damage. Meanwhile, in the range of 0-60 mu g/ml, the tyrosinase inhibitory activity of EEMT increased with increase in sample concentration, and was superior to that of the ethanolic extract of mulberry root bark (EEMR). High-performance liquid chromatography (HPLC) analysis was employed to determine the phenolic components, revealing that maclurin, rutin, isoquercitrin, resveratrol, and morin were present in EEMT. Acting as an antioxidant and a tyrosinase inhibitor, these bioactive constituents could contribute to the protective effects of EEMT. Overall, the results showed that EEMT might serve as a natural antioxidant and tyrosinase inhibitor. (C) 2010 Elsevier Ltd. All rights reserved.