Bioactives from stems and leaves of mung beans (Vigna radiata L.)

After the harvest of the seeds of mung beans (Vigna radiata L.) (MB), a significant quantity of by-products (stems, leaves) is generated. The aim of this study was to isolate key bioactive components from MB with antioxidant and antidiabetic activities. Two new isoflavones, thirteen known flavonoids, and seven known lignans were obtained. Their structures were identified by extensive 1D and 2D NMR, and FT-ICR-MS spectroscopic analyses. The antioxidant and antidiabetic activities of these compounds were also evaluated. Thienty-two compounds presented moderate to stronger antioxidant activities than those of L-ascorbic acid in ABTS and FRAP assays. However, only 3'-methoxydaidzein and erythro-buddlenol B showed DPPH. scavenging activity. In addition, the lignans (EC50 = 2.92-32.76 mu M) displayed a more positive effect on alpha-glucosidase inhibition than the flavonoids (EC50 = 4.00-93.41 M). The results obtained show that MB can be regarded as a potential new and inexpensive source of antioxidants and antidiabetic agents. (C) 2016 Elsevier Ltd. All rights reserved.