MICROWAVE-ASSISTED EXTRACTION AND LIQUID CHROMATOGRAPHY/MASS SPECTROMETRY ANALYSIS OF FLAVONOIDS FROM GRAPEFRUIT PEEL

摘要

The flavonoids of grapefruit peel were obtained by microwave-assistednextraction. Five constituents have been identified by liquid chromatographymass spectrometry analysis such as hesperitin-7-O-glucoside, isonaringin,nnaringin, 2u0002,5u0002-dihydroxy-3,4u0002,5,6,7-pentamethoxyflavone and neoeriocitrin.nThe last two compounds are reported first in grapefruit peel. The effects ofnsolvent, time, ratio of solvent to material (liquid/solid) and output power onnthe extraction were investigated. The results show that the better extractionnconditions are: 80% (v/v) ethanol as extraction solvent; 3 min of extractionntime, 25:1 (mL/g) as the ratio of liquid to solid; and 560 W of microwavenoutput power. Microwave-assisted extraction is more efficient for getting flavonoidsnfrom grapefruit peel than reflux and ultrasonic extraction methods.nThe yield of optimized microwave-assisted extraction reached 5.81%.