| Detailed laboratory research on antioxidant activities, is carried systemly in this paper, with an emphasis on three types of species of citrus, which are Pankan(C.reticulate Blanco) , Liangpingyou [C.grandis(L.) Osbeck] and Jinchen[C.sinensis(L.) Osbeck], respectively. Studying contents are following: inhibition of extracts from citrus peel on the autooxidation of lard ; scavenging effect of extracts from citrus peel on H2O2, . OH and O- 2 choosing the water extract of Liangpingyou and Pankan for experiments in vivo; and analyzing main active ingredients which are confined to water-solvable flavonoids. Now these results of research are summed up as the followings:1. Reasons that types of breeds are chosen for research objectsCitrus L. is one of the biggest yields of fruits in the world. The output of citrus L. in China was up to 1012.2 ten thousands of duns in 1997. it comes out from statistical data that at present the cultivated area of Pankan is taking up 13.73 percent of the total and its yield is 21.35 per of the total; the cultivated area of Pomelo is taking up 11.75 percent of the total and its yield is 9.78 per of the total(58) The total output of citrus in Chongqing is up to over 60 ten thousands of duns in 1999 and 2000. Citrus peel as the waste material is holding 20-40 percent of the whole. We regard as the research objects the peel of Pankan and Liangpingyou, and residues of Jinchen after being pressed for fruit juice. We had planed a set of laboratory research on the antioxidant activities in vitra and vivo, and functional ingredients of these. It has not been found that detailed studying on these of peel of pomelo and pankan2. Inhibition of extracts from citrus peel or residues on the autooxidation of lard Extracts from Liangpingyou strongly restrain the autooxidation of lard. 0.02% ofBHT is equal to 0.8% of 70%-ethanol, 2% of n-butanol and 2% of ethyl acetate from Liangpingyou peel, respectively. The first is much stronger than the other two of the three. High concentration of 70% ethanol extract from Liangpingyou peel doesn't promote autooxidation of lard but stops that more strongly clearly. All extracts of peelfrom Pankan and residues from Jinchen are somewhat weaker than those of Pomelo peel in the aspect of inhibition of autooxidation of lard.3. Scavenging effect on H2O2Water extract of Liangpingyou peel can hold back activity of H2O2 powerfully. Its IC50 (Concentration of extracts in the reaction system which can scavenge 50 percent of free radicals) is 70.2mg(wet peel)/ml, while IC50 of extracts of peel from Pankan and residue from Jinchen is 124.3 and 326.5 mg (wet peel)/ml, respectively. So scavenging effect of water extracts on H2O2 is put in order of Liangpingyou>Pankan>>Jinchen, and related correspondingly to their concentration. The scavenging effect of water extract from Liangpingyou peel is outstanding among those. It can scavenge all 1.0 ml H2O2(0.1mol/L) while 5.0 ml of it was added to the reaction system. The IC50 of 70% ethanol extract from Liangpingyou peel is 133.8mg(wet peel)/ml far higher than water extract of it, while scavenging effect of 70% ethanol extracts from Pankan and Jinchen is poor and there is no obvious effect correspondingly when concentration of them was increased. The scavenging ability of other extracts in the experiment is feeble relatively.4. Scavenging effect on . OHFenton reaction was used to test the scavenging effect of water, ethanol, n-butanol and ethyl acetate extracts from the peel of Pankan and liangpingyou or the residue of Jinchen for hydroxyl free radicals with mannitol (IC50 is 1.9mg/ml in the experiment) as the control. The IC50 of water, 70% ethanol, n-butanol and ethyl acetate extracts from Pankan, Liangpingyou and Jinchen was 3.7, 6.5 and 5.6; 36.2 and 50.0; 5.2, 29.2 and 4.4; 5.4, 30.0 and 4.6 mg (wet peel)/ml respectively and scavenging ability of them was correspondingly related to their concentration. It is, therefore, concluded that the water extract from all the three Citrus species and the n... |
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