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Luo W.,South China University of Technology | Wen L.,South China University of Technology | Zhao M.,South China University of Technology | Yang B.,CAS South China Botanical Garden | And 3 more authors.
Food Chemistry | Year: 2012

The air-dried fruit hull of Phyllanthus emblica L. was extracted with 95% ethanol, and then the extract was partitioned by diethyl ether and ethyl acetate (EA). The EA fraction was then subjected to separation and purification using silica gel and Sephadex LH-20 column chromatography repeatedly to obtain five hydrolysable tannins. They were identified as mucic acid 1,4-lactone 3-o-gallate (C1), isocorilagin (C2), chebulanin (C3), chebulagic acid (C4) and isomallotusinin (C5) using mass spectrometry and nuclear magnetic resonance (NMR) spectrometry. Isomallotusinin and chebulanin were identified from emblica dried fruit hull for the first time, and isomallotusinin was the first time identified from Phyllanthus. Furthermore, the antioxidant abilities of these hydrolysable tannins were investigated using DPPH and ABTS + radical scavenging systems. All hydrolysable tannins showed strong DPPH and ABTS + radical scavenging activities. Isomallotusinin and chebulagic acid exhibited the highest antioxidant activity compared to other purified compounds tested. © 2011 Elsevier Ltd. All rights reserved. Source


Luo W.,South China University of Technology | Zhao M.,South China University of Technology | Yang B.,CAS South China Botanical Garden | Ren J.,South China University of Technology | And 2 more authors.
Food Chemistry | Year: 2011

Phyllanthus emblica is a widely distributed tropical medicinal plant with good therapeutic properties. Gallic acid, ellagic acid, mucic acid 1,4-lactone 3-O-gallate, isocorilagin, chebulanin, chebulagic acid and mallotusinin were isolated and purified from this plant. The antioxidant activities of these compounds were evaluated by in vitro models of scavenging superoxide anion radicals, DPPH radicals and ABTS radicals, chelating ability of ferrous ion and inhibition capability of Fe (II)-induced lipid peroxidation, respectively. The results revealed that all the tested phenolics showed strong radical scavenging activity, good potency to chelate Fe 2+ and good inhibition ability of lipid peroxidation. Amongst mallotusinin and mucic acid 1,4-lactone 3-O-gallate were reported for the first time to have antioxidant activity. In addition, the in vitro antiproliferative activities of those phenolics against MCF-7 breast cancer cell lines were assessed. Although the growth inhibition values induced by different phenolics on MCF-7 cell line yielded different effects, all the tested phenolics had apparent capacities of inhibiting the survival of MCF-7 human cancer cell line. © 2010 Elsevier Ltd. All rights reserved. Source


Shen G.,Guangdong Branch of China Tobacco Industry Co. | Tao H.,Guangdong Branch of China Tobacco Industry Co. | Zhao M.,South China University of Technology | Yang B.,CAS South China Botanical Garden | And 3 more authors.
Journal of Food Process Engineering | Year: 2011

In this work, the effect of oxidation pretreatment on the enzymatic hydrolysis of cellulose in tobacco stems was evaluated. A comparison was made between the effect of H 2O 2 pretreatment and conventional alkali pretreatment on the weight loss of cellulose, lignins and hemicelluloses of tobacco stems. The effects of H 2O 2 concentration, pretreatment time and temperature on the enzymatic hydrolysis of tobacco stems were investigated. This pretreatment could give a higher recovery of cellulose and better removal of lignin and hemicellulose than alkali-only pretreatment. Compared with the untreated stems, the yield of reducing sugar pretreated by H 2O 2 pretreatment (pH 11.5, 0.6% H 2O 2) for 9 h at 60C increased 347.2%. The results of scanning electron microscope and X-ray diffraction analysis also showed that the structural and crystalline properties of the tobacco stems were changed by pretreatment, and they were in favor of the following enzymatic hydrolysis. The optimal pretreatment conditions were 60C of temperature, 0.6% of H 2O 2 concentration and 9 h of time, which were calculated by orthogonal experiments. © 2009 Wiley Periodicals, Inc. Source

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