Abstract
The present study was designed to evaluate relative contribution of different polyphenols (total phenolics, flavonoids, flavonols) and their antioxidants activities in aqueous extracts of different parts of some plants; Argemone mexicana, Datura metel, Calotropis procera, Thevetia peruviana, and Cannabis sativa. The antioxidants (total phenolics, flavonoids, flavones) were determined by chemical methods. The antioxidant capacities of these extracts were evaluated by FRAP assay. The results demonstrated that phenolic content was maximally present in leaves of T. peruviana. This plant exhibited minimum phenolic content in its flower as compared to other plants. The flower of D. metel contained maximum phenolic content. The flavonoids were present in highest quantity in leaves of C. procera while T. peruviana flowers showed maximum flavonoid content. The fruits of C. sativa contained maximum quantity of flavonoid as compared to other plants tested. The flower extract of C. sativa possessed highest FRAP value followed by A. mexicana and fruit of C. procera. The values of ratios of different polyphenolic compounds present in plant extracts indicated that flower of D. metel contained maximum total flavonoids and minimum phenolics. These results suggested that levels of total phenolics, flavonoids and their FRAP indices exhibited specificity to different plants and their parts.