Qualitative And Quantitative Analysis Of Anthocyanins In Red Onion And Black Soybean Hull And Study On Their Biological Activities

Red onion and black soybean hull belong to medicinal and edible plants.They have been used for medicinal purposes for over hundred years.In recent years,they have attracted much attention owing to anthocyanins,which are rich in those plants.Anthocyanins are natural pigments,which contribute to red,purple and blue of vegetables,fruits and flowers.The most attractive of anthocyanins are beneficial to human health,antioxidant,anti-cancer,free radical scavenging,lipid-lowering and platelet aggregation inhibition and other bioactivities.Thus,anthocyanins are considered to have broad application prospects in medicine and health industry.In this paper,red onion and black soybean hulls were selected as material to study the content,structure and stability and the biological activity of anthocyanins.Provide pharmacological basis for further studies on anthocyanins and epidemiological related to human health and for improving the medicinal value and the development of anthocyanins in red onion and black soybean hull.Chapter 1: The structure,physicochemical characteristics,bioactivity,application and the methods of qualitative and quantitative analysis of anthocyanins were summarized.The research of anthocyanins from red onion and black soybean hull were briefly summarized.Chapter 2: Selected red onion as material,the anthocyanins in red onion were extracted by ultrasound-assisted method.Four main anthocyanins(Cyanidin 3-O-glucoside,Delphinidin 3-O-glucoside,Cyanidin3,5-O-diglucosides,Delphinidin 3,5-O-diglucosides)were preliminarily identified by high performance liquid chromatography-mass spectrometry(HPLC-MS).The content of anthocyanins in the extract of red onion was9.03mg/100 g FW by p H-differential method and total phenol was 82.54 mg GAE/100 g by Folin-ciocalteu method.The effects of temperature,p H and common metal ions on the stability of anthocyanins were analyzed by UV-Vis absorption spectroscopy.The results showed that the temperature waslower than 30 C,the p H was less than 2,which was beneficial to the preservation of red onion anthocyanins.Al3+ and Fe3+ can enhance the stability of anthocyanins from red onion.Chapter 3: Using black soybean hull as material,the anthocyanins were extracted by ultrasound-assisted method.The quantitative analysis method of Cyanidin 3-O-glucoside by HPLC in black soybean hull was established.The chemical constituents of black soybean hull extract were studied by silica gel column chromatography,ODS column chromatography,Sephadex LH-20 column chromatography and semi-preparative HPLC separation methods.The structures of the compounds were identified by HPLC-MS and Nuclear Magnetic Resonance(NMR).Seven compounds were isolated and identified as Cyanidin 3-O-glucoside(1),Protocatechuic acid methyl ester(2)and Ethyl 3,4-dihydroxybenzoate(3),Daidzein(4),Quercetin dihydrate(5),Genistein(6),Isorhamnetin(7).Chapter 4: The anthocyanins extract of red onion,black soybean hull and Cyanidin 3-O-glucoside were selected as the research object,the antioxidant activity and the inhibitory of a-glucosidase of anthocyanins were analyzed.ABTS(2'-hydrazine-bis-3-ethylbenzothiazoline-6-sulfonic acid)and DPPH(1,1-diphenyl-2-picrylhydrazine)methods were selected to analyze the antioxidant activity and 4-MUG(4-methylumbelliferone-beta-D-glucoside)was selected as substrate to study the inhibition of a-glucosidase.Compared with Vc,they showed strong antioxidant capacity.And their inhibition ability was lower than that of acarbose,but they exhibited the potential to inhibit ?-glucosidase.