Antioxidant activity and phenolic compounds in 32 selected herbs

Total equivalent antioxidant capacities (TEAC) and phenolic contents of 32 spices extracts from 21 botanical families grown in Poland were investigated. The total antioxidant capacity was estimated by the following methods: ABTS(center dot)+ (2,2'azinobis-(3-ethylbenzthiazoline-6-sulfonic acid)), DPPH center dot (1,1-diphenyl-2-picrylhydrazyl radical) and ferric reducing/antioxidant power (FRAP) expressed as TEAC. The total phenolics were measured using a Folin-Ciocalteu assay. Qualitative and quantitative analyses of major phenolics by reverse-phase high-performance liquid chromatography (RP-HPLC) were also used. Major phenolic acids identified in analyzed species were caffeic, p-coumaric, ferulic and neochlorogenic, while predominant flavonoids were quercetin, luteolin, apigenin, kaempferol and isorhamnetin. Myricetin was detected only in Epilobium hirsuturn. Many investigated spices had high levels of phenolics and exhibited high antioxidant capacity. The TEAC values of the spices ranged from 1.76 to 346 mu M trolox/1.00 g dw, from 7.34 to 2021 mu M trolox/100 g dw, and 13.8 to 2133 mu M trolox/100 g dw for ABTS(center dot+), DPPH center dot and FRAP, respectively. The total phenolic content, measured using a Folin-Ciocalteu assay, ranged from 0.07 to 15.2 ing of gallic acid equivalents (GAE)/100 g dw. The herbs with the highest TEAC values were Syzygium aromaticum, E. hirstitum and the species belonging to the Labiatae and Compositac family. A positive relationship between TEAC (ABTS(center dot+) and FRAP) values and total phenolic content, measured by HPLC, was found only in family groups with many representative herbs within Labiatae and Compositae. (c) 2007 Elsevier Ltd. All rights reserved.