Optimization purification characterization of quercetin extracted from onion skin radish leaves and fenugreek stems

Abstract

Quercetin was isolated from crude extract of vegetable wastes like onion skin, radish newlineleaves and fenugreek stems by three extraction methods such as Microwave Assisted newlineExtraction, Soxhlet Extraction and Maceration with the help of three different Ethanol newlineconcentrations (30 %, 60 % and 90 %). Phytochemical analysis such as total phenolic newlinecontent (TPC), total flavonoid content (TFC) and antioxidant activity of crude extract newlinewas also conducted spectrophotometrically. Quantification of Quercetin in extracts was newlinedone by HPLC at 254 nm wavelength and purification by using column chromatography newlineand thin layer chromatography. Microwave extraction exhibited higher extraction yield newlineof 18.93 %, 35.33 % and 32.13 % for onion skin, radish leaves and fenugreek stems newlineextract with 30% Ethanol respectively. TPC, TFC and antioxidant activity were also newlinehigher for microwave extraction than that of conventional extraction. The maximum newlineTPC was found as 519.25, 177.5 and 149.75 mg GAE/g for onion skin, radish leaves and newlinefenugreek stems extract with 90 % Ethanol respectively. Best results of TFC were newline120.75, 55.09 and 43.46 mg QE/g for onion skin, radish leaves and fenugreek stems newlineextract with 90 % Ethanol at 300W respectively. Free Radical Scavenging Activity newline(FRSA) of onion skin extract ranging from 42.22 to 84.68 for which minimum IC50 newlinevalue of 37.75 µg/ml was recorded, FRSA of radish leaves extract ranging from 34.64 to newline78.70 % for which IC50 value of 65.73 µg/ml was calculated and FRSA of fenugreek newlinestems extract ranging from 37.6 to 77.99 % for which IC50 value of 63.01 µg/ml was newlinecalculated. Quercetin yield for onion skin extract, radish leave extract and fenugreek newlinestem extract was higher for microwave extraction at 400 W with 90 % Ethanol i.e. newline14.44, 3.44 and 0.54 µg/g respectively. Purified Quercetin from onion skin gave the newlinehigher yield (170 mg, 3.4 %) than radish leaves and fenugreek stems. Antioxidant newlineactivity of purified Quercetin was compared with Ascorbic acid, from the results it can newlinebe concluded tha