Antioxidant capacities and total phenolic contents of infusions from 223 medicinal plants

Abstract

In order to find new sources of natural antioxidants, antioxidant capacities of infusions from 223 medicinal plants were systemically evaluated using ferric-reducing antioxidant power (FRAP) and Trolox equivalent antioxidant capacity (TEAC) assays, and their total phenolic contents (TPC) were measured by Folin–Ciocalteu method. A very weak correlation (R2=0.1563) between the TEAC value and the FRAP value suggested that the components capable of scavenging free radicals could be different from those reducing oxidants in these plants. A significant correlation (R2=0.7549) between TEAC value and TPC as well as a very weak correlation (R2=0.1966) between FRAP value and TPC implied that phenolic compounds in these plants could be the main components contributing to scavenging free radical activities, but not be responsible for reducing oxidant abilities. Several plants possessing the high antioxidant capacities and TPC have been screened out, which could be potential rich resources of natural antioxidants, and could be developed into herbal infusion, functional food or pharmaceuticals for prevention and treatment of diseases caused by oxidative stress.