The study was to investigate the changes of α-amylase inhibitor content in Pu-erh tea during pile-fermentation process. Pu-erh tea samples from two regions of Shuangjiang County and Jinggu Dai and Yi Autonomous Count...The study was to investigate the changes of α-amylase inhibitor content in Pu-erh tea during pile-fermentation process. Pu-erh tea samples from two regions of Shuangjiang County and Jinggu Dai and Yi Autonomous County of Yunnan Province at various fermentation stages were used as experimental materials to investigate the effect of different fermentation stages on the inhibitory effect to α-amylase; and the change law of the inhibitory effect of c-amylase inhibitor during processing was meanwhile studied by determining the contents of tea polyphenol and amino acid. The results showed that crude meterial of Pu-erh tea presented strong inhibitory effect to α-amylase; this inhibitory effect assumed a de： creasing trend to the minimum at the middle stage of fermentation, whereafter it increased to some extent. Made tea also showed a strong inhibitory effect to α-amylase. During whole processing period, contents of tea polyphenol and amino acid generally assumed a remarkably decreasing trend. Our results provided references for further isolating co-amylase inhibitor from Pu-erh tea and discussing the mechanism of its health care function.展开更多
In the present study, we studied the inhibitory effects of chelidonine and rutaecarpin on porcine pancreatic a-amylase （PPA） catalyzed hydrolysis using 2-chloro-4-nitrophenyl-4-O-β-D-galactopyranosylmaltoside （Gal...In the present study, we studied the inhibitory effects of chelidonine and rutaecarpin on porcine pancreatic a-amylase （PPA） catalyzed hydrolysis using 2-chloro-4-nitrophenyl-4-O-β-D-galactopyranosylmaltoside （Gal-G2-α-CNP）. We, for the first time, provided kinetic report and detailed inhibitory effects of both compounds on PPA. Lineweaver-Burk plot revealed that the inhibition was a mixed-noncompetitive type, and only one molecule of inhibitor bound to the enzyme or to the enzyme-substrate complex. Kinetic constants calculated from secondary plots were in millimole range. Dissociation constants of enzyme-inhibitor complex （KEI） were 0.9 mM and 3.5 mM, respectively. Moreover, dissociation constants of enzyme-inhibitor-substrate complex （KESI） were 0.04 mM and 0.31 mM, respectively. These data indicated that the inhibition was more inclined to competitive to Gal-G2-α-CNP hydrolysis. Further molecular docking study manifested that hydrogen bonding formed between acarbose and aspartic acid （Asp300）, histidine （His305） and glycine （Gly3-6）, while hydrogen bonding was observed between chelidonine and glutamic acid （Glu233）, lysine （Lys200） and His305. In addition, rutaecarpine had only one hydrogen bond with Lys200. Our data indicated that chelidonine and rutaecarpine were two promising drug candidates, and chelidonine possessed stronger inhibitory effect compared with rutaecarpine.展开更多
文摘The study was to investigate the changes of α-amylase inhibitor content in Pu-erh tea during pile-fermentation process. Pu-erh tea samples from two regions of Shuangjiang County and Jinggu Dai and Yi Autonomous County of Yunnan Province at various fermentation stages were used as experimental materials to investigate the effect of different fermentation stages on the inhibitory effect to α-amylase; and the change law of the inhibitory effect of c-amylase inhibitor during processing was meanwhile studied by determining the contents of tea polyphenol and amino acid. The results showed that crude meterial of Pu-erh tea presented strong inhibitory effect to α-amylase; this inhibitory effect assumed a de： creasing trend to the minimum at the middle stage of fermentation, whereafter it increased to some extent. Made tea also showed a strong inhibitory effect to α-amylase. During whole processing period, contents of tea polyphenol and amino acid generally assumed a remarkably decreasing trend. Our results provided references for further isolating co-amylase inhibitor from Pu-erh tea and discussing the mechanism of its health care function.
基金State Key Laboratory of Natural and Biomimetic Drugs 2013 Funded Project "Establishment and Application an Online Natural Medicines System with Efficient Separation,Structural Identification and Activity Detection"
文摘In the present study, we studied the inhibitory effects of chelidonine and rutaecarpin on porcine pancreatic a-amylase （PPA） catalyzed hydrolysis using 2-chloro-4-nitrophenyl-4-O-β-D-galactopyranosylmaltoside （Gal-G2-α-CNP）. We, for the first time, provided kinetic report and detailed inhibitory effects of both compounds on PPA. Lineweaver-Burk plot revealed that the inhibition was a mixed-noncompetitive type, and only one molecule of inhibitor bound to the enzyme or to the enzyme-substrate complex. Kinetic constants calculated from secondary plots were in millimole range. Dissociation constants of enzyme-inhibitor complex （KEI） were 0.9 mM and 3.5 mM, respectively. Moreover, dissociation constants of enzyme-inhibitor-substrate complex （KESI） were 0.04 mM and 0.31 mM, respectively. These data indicated that the inhibition was more inclined to competitive to Gal-G2-α-CNP hydrolysis. Further molecular docking study manifested that hydrogen bonding formed between acarbose and aspartic acid （Asp300）, histidine （His305） and glycine （Gly3-6）, while hydrogen bonding was observed between chelidonine and glutamic acid （Glu233）, lysine （Lys200） and His305. In addition, rutaecarpine had only one hydrogen bond with Lys200. Our data indicated that chelidonine and rutaecarpine were two promising drug candidates, and chelidonine possessed stronger inhibitory effect compared with rutaecarpine.
