Determination of Anti-oxidant Activity of Ethanol, Ethyl acetate, Hexane, and Aqueous Extracts of Sri Lankan Traditional Poly-herbal Formula Nāgarādi Panchakaya

Natural products are the good source of natural antioxidants. Nāgarādi panchakaya is a well-known poly-herbal formula prescribed specially for upper respiratory tract diseases by Sri Lankan Ayurveda medical practitioners. The name implies that it contains five herbal ingredients including Inguru (Zingiber officinale), Devadāra (Cedrus deodara), Kottammalli (Coriandrum sativum), Ela batu (Solanum indicum) and Katuwelbatu (Solanum xanthocarpum). This research study was aimed to determine the antioxidant activity of Nāgarādi panchakaya, extracted with different solvents (ethanol, ethyl acetate, n-hexane and water). Antioxidant activity was evaluated by using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay method and the Ferric Reducing Antioxidant Power (FRAP) assay. In vitro antioxidant free radicals scavenging capacities of different concentrations of ethanol, ethyl acetate, n-hexane and water extracts, of Nāgarādi panchakaya were evaluated. The percentage of inhibition and IC50 were calculated. IC50 (μg/mL) of water, ethanol, ethyl acetate, n-hexane and Ascorbic Acid were found to be 179.89±1.25 µg /mL, 248.09±1.74 µg /mL, 169.43± 0.98µg /mL, 189.56±2.23 µg /mL, and 01.18±0.98 µg /mL respectively in DPPH radical scavenging assay. In FRAP assay the reducing power for the different extracts varied in following order: water > ethanol > ethyl acetate > n-hexane. The total Phenolic content of water, ethanol, ethyl acetate and n-hexane extracts were 1.73±0.51 mg GAE/g, 2.59±0.67 mg GAE/g, 3.67±0.81 mg GAE/g and 1.57±0.09 mg GAE/g respectively. The results can be concluded that Ethanol & water extracts exhibit high antioxidant activity possibly due to the presence of high phenolic content than the other extracts.