Studies On The Active Constituents Of Epimedium Koreanum Nakai And Freeze-thaw Characteristics And Microstructure Of Three Types Of Starches

Epimedium koreanum Nakai has been used as a nutraceutical in functional foodsor a phytopharmaceutical for preventing and curing some serious and fatal illnessessuch as cardiovascular diseases, osteoporosis and to improve neurological and sexualfunction. In this study, response surface methodology was applied to determine theoptimal conditions for ultrasonic-assisted extraction (UAE) of lfavonoids, icariin andantioxidant activity from Epimedium koreanum Nakai. The optimal conditions forUAE of flavonoids were ratio of solvent to solid40ml/g, extraction time45min andultrasonic power150w. Under these conditions, the extraction yields of flavonoids,icariin and1,1’-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activityachieved were273.79mg/g,18.9mg/g and87.15%, which increased by73.86%,290.50%and48.26%, respectively, as compared with the control extraction.The antioxidant activities of ethanol extract, petroleum ether, ethyl acetate,n-BuOH and water fraction fractions of ethanol extract from the leaves and stem ofEpimedium koreanum Nakai were also investigated in this study. The results showedthat all the extracts and fractions exhibited antioxidant and antioxidant activities atdifferent magnitudes of potency. The leaf extract and fractions from Epimediumkoreanum Nakai demonstrated superior antioxidant activity in most of the assays. Theethyl acetate and n-butanol fraction of leaf extract might be valuable antioxidantnatural sources and seemed to be applicable in both healthy medicine and foodindustry.The petroleum ether，ethyl acetate and n-butanol fraction were isolated andpurified using silica column chromatography, Sephadex LH-20columnchromatography, preparative HPLC and preparative TLC. The compounds isolatedfrom these three fractions were identified by^-NMR etc.Three compounds were isolated from petroleum ether fraction, two compoundswere identified as22-hydroxyhapan-3-one (1) and^-sitosterol (2). Thirteencompounds were isolated from ethyl acetate fraction, eight compounds were identifiedas daucosterol (3), Epimedoicarisoside A (4), baohuoside I (5), icarisid-I (6), icaritin(7), hypericin (8), icariin (9), quercetin (10). One compound was isolated andidentified from n-butanol fraction fraction as icariin (1). Others, potato, chestnut and yam are widely cultured in China. Over the last fewyears, there were many studies on the physicochemical properties on the starches frompotato, chestnut and yam. Three types of starches from chestnut, starch and yam werecomparatively studied by freeze-thaw cycle (FTC) treatments from1to5. Among thethree types of starches, potato starch was worst in the crystal. It is easiest for chestnutstarch to degrade and potato starch might be the good resource of resistant starchproduction.