| The rapid development of molecular biology and food sciences has been improving the human's understanding on the free radicals and their harmful function existing in biological system and food so that great attention has been paid to how to dismiss the extra free radicals and control the per-oxidation of the lipid. However, most artificial antioxidants used widely in foods have the potential toxicity and carcinogenicity. So it is the most significance to find the natural and highly effective antioxidant from the natural plant resources.In the study, the natural resource, Monochoria vaginalis, was used for isolating and identifying the natural antioxidant by column chromatography method and then the anti-oxidation activity of the isolates was analyzed for value. By the analyses of using HR-MS, 1HNMR, 13CNMR and other methods, two active substances were isolated in the study: the chemical form for Chemical 1 was C29H48O2 with molecular weight 428 and the chemical form for Chemical 2 was C14H28O2 with molecular weight 428. Chemical 1 was firstly isolated firom this plant and was supposed a kind of steroid and Chemical 2 was 14 carbonic acid.The total antioxidant activities (TAA) of two chemicals were determined by the method of ABTS. The results showed that the Chemical 1 presented higher antioxidant activities than that of natural antioxidant tea polyphenols, lower than artificial antioxidant butylated hydroxyl toluene (BHT) and its 50% of ABTS free radical inhibitory consistency (IC50) was 9.4μg/mL; the antioxidant activity of Chemical 2 was lower than tea polyphenols and BHT, its IC50 was 64.2μg/mL. The results of eliminating superoxide anion free radicals and scavenging hydroxyl free radical of two chemicals showed that the eliminating activity of superoxide anion free radical of Chemical 1 was higher than that of BHT, the artificial antioxidant, the maximum eliminating rate (E) was 60.87%, higher than 55.49% of BHT. The scavenging activity of hydroxyl free radical was also higher than BHT, which was 50.46%; Chemical 2 was also had capability of eliminating superoxide anion free radicals and scavenging hydroxyl free radical with index of 46.08% and 26.42% respectively. The results of antimicrobial activity trials of the two chemicals showed that Chemical 1 had antimicrobial activities to Saccharomyces cerevisiae, Penicillium cyclopium, Rhizopus sp., Bacillus subtilis, Proteus vulgaris and the minimum inhibitory consistency (MIC) was 0.0625 mg/mL,0.5 mg/mL,0.125 mg/mL,0.5 mg/mL,0.25 mg/mL respectively; Chemical 2 had antimicrobial activities to Penicillium cyclopium, Rhizopus sp., Escherichia coli, Proteus vulgaris and the MIC was 0.125 mg/mL,0.25 mg/mL,0.5 mg/mL,0.5 mg/mL respectively.To determine the the antioxidation activities of the other two plants of Pontederiaceae the same as Monochoria vaginalis, the compared analyses of the antioxidative activities of the extracts from Monochoria vaginalis, Monochoria korsakowii, Eichhornia crassipes with the different solvents were carried out by TBARS method. The results showed that acetidin extract of Monochoria vaginalis had the highest anti-oxidative activity among all the extracts in the study, higher than the control, the natural antioxidant tea polyphenols and the same with that of artificial antioxidant BHT. The preservative ability on lipid and hypolipidemic effect on rats of acetidin extract of Monochoria vaginalis were also determined in the study. The lipidic preservative results showed that the lipidic preservative ability of Monochoria vaginalis acetidin extract was higher than that of tea polyphenols, while it was the same with that of BHT. The results of hypolipidemic effect on rats showed that TC of the rats from the group with Monochoria vaginalis acetidin extracts was decreased significantly, TG, LDL-c, HDL-c had decreasing trend respectively. The Monochoria vaginalis acetidin extracts had a potential effect on decreasing hyporlipidemia in hyperlipidemia rats. |
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