| Japanese persimmon (Diospyros kaki Thunb.) belongs to the genus Diospyros(Ebeuaceae), is a native and special fruit tree of China, and has been planted for thousandsyears in east of Asian. Persimmon tree is widely distributed in China and well-adapted; italso has high production and great profit for grower. What’s more, it’s fruits have beautifulcolour with rich nutrition. It has a lot of application which can not only eat, make aspancake, cake, but also be used to make wine and vinegar. The last but not the least, it hasgreat medicine value to keep healthy. Flavonoids are ubiquitous phytochemicals, which area broad class of low molecular weight, secondary plant phenolics characterized by theflavan nucleus and widely distributed in the leaves, seeds, bark and flowers of plants. It canbe used as antioxidant, free radical scavenger and succimer, in medicine, it can alsoantibiosis, antiviral, antiallergic, and dilate blood vessels.However, the study on persimmon inclusion often focus on organic acids, polyphenols,carbohydrates, vitamin C, dietary fibers, triterpenic acid, carotenoid and flavonoidswhich is less about flavonoids. In our study, on the basis of extraction technology andcomponent separation of persimmon flavonoids, we concentrate on the antioxidant activityto study.In our study, two kinds of persimmon, which are Yangfeng (Pollination constantnon-astringent) and Mopan (Pollination constant astringent) were collected from theyoung fruit period to mature period to find the changes along as the time goes by and theflavonoids distribution in different organs. we also chose51cultivars persimmon duringtheir mature period to determine the flavonoids contents in them. The results as follows:1.The ultrasonic-assisted extraction technique for flavonoids from ‘Mopan’persimmon pulp was studied, and the optimization of technological parameters wereobtained by Response surface methodology (RSM) with flavonoids extraction rate as index,and the antioxidant activities of flavonoids in the extracts were determined. The optimalextraction conditions were using70%ethanol as solvent, ratio of liquid to solid50:1,extraction time of50min, ultrasonic power of450W and obtained the extraction rate of1.57%. The results showed good fits with the proposed model for flavonoids extraction rate (R2=0.95). In vitro antioxidant assays showed that the flavonoids exhibited strongDPPH radicals scavenging activities (93.07%at0.25mg/ml) and Ferric reducing power(1.98mmol/l at0.25mg/ml), which are both higher than that of BHT (positive control). Atthe same time, it was found that the antioxidant activity appeared to beconcentration-dependent of flavonoids. The knowledge gained from this study would bebeneficial to further exploit and apply the persimmon resource.2. The experiment improved a method to isolate the flavonoids constituent.7kindsof flavonoids constituents which are Catechin, Epicatechin, Rutin, Hyperoside,Isoquercetin, Astragalin, Quercetin were isolated.3. In different development periods, the highest total flavonoids content existed inpulps and peels; with the fruit develop, the total flavonoids content reduced. In ‘Yangfeng’pulp, the highest flavonoids constistunent content of most kinds of flavonoids existed inyoung fruits period which is contrary to ‘Mopan’ pulp. What’s more, the most flavonoidsconstituents with highest content of peels and leaves exist in mature period.4. In different organs, the highest toal flavonoids content existed in pulps in the youngfruit period. In colouring period and mature period, the highest total flavonoids andflavonoids constitunent content are in leaves. What’s more, the Epicatechin with highestcontent was in the pulps, the rutin with highest content was in peels.5. In the mature period of different cultivars, the total flavonoids content in peelswas between249.01±15.94mg/100g DW and2996.14mg/100g DW. The total flavonoidscontent in pulps was between38.71mg/100g DW and1870.69mg/100g DW. In leaves, it’scontent between1468.94mg/100g DW and8805.23mg/100g DW. |
