Vol. 5, Issue 3, Part D (2019)

Abstract
In this study, the antioxidant properties and total phenolic and flavonoid contents of Rheum emodi rhizome extracts were examined. The radical scavenging capacity of Petroleum ether, chloroform, ethyl acetate and 90% ethanol extracts was estimated by 2, 2-diphenyl-1-picrylhydrazil (DPPH) assay. Phenols and flavonoids were present only in the ethyl acetate and 90% ethanol extracts, their total phenols and flavonoids contents were determined. Total phenolic content in the 90% ethanol and ethyl acetate extracts were 51.57±0.09, 69.75±1.13 mg gallic acid equivalent (GAE)/g and total flavonoid content 11±0.14, 29.5±0.01 mg Quercetin equivalent (QE)/g of extract respectively. The highest DPPH antioxidant activity was shown by 90% ethanol extract IC₅₀ 52.04 followed by ethyl acetate extract IC₅₀ 59.68 and least by petroleum ether extracts IC₅₀ 156.62 while standard ascorbic acid was IC₅₀ 28.26. Our results of antioxidant assays were justified and partially supported the popular usage of the tested plants. The high antioxidant activity found in the plant can be a good source of natural antioxidants which might have benefits for health.