Fish skin collagen hydrolysates （FSCH） were prepared from walleye pollock （Theragra chalcogramrna） using a mixture of enzymes, namely trypsin and flavourzyme. The degree of hydrolysis of the skin collagen was 27.3...Fish skin collagen hydrolysates （FSCH） were prepared from walleye pollock （Theragra chalcogramrna） using a mixture of enzymes, namely trypsin and flavourzyme. The degree of hydrolysis of the skin collagen was 27.3%. FSCH was mainly composed of low-molecular-weight peptides and the relative proportion of 〈1000Da fraction was 70.6%. Free radical and oxygen species scavenging activities of FSCH were investigated in four model systems, including diphenylpicrylhy-drazyl radical （DPPH）, superoxide anion radical, hydroxyl radical and hydrogen peroxide model, and compared with that of a native antioxidant, reduced glutathione （GSH）. FSCH was also evaluated by water-absorbing and water-holding capacity. The results showed that FSCH was able to scavenge free radical and oxygen species significantly and to enhance water-absorbing and water-holding capacity remarkably. Therefore FSCH may have potential applications in the medicine and food industries.展开更多
Applying quantitative temporal analysis of products reactor measurements, we studied the reactive removal of active oxygen present on Au/TiO2 catalysts after calcination at elevated temperatures （400 ＆#176;C） by CO...Applying quantitative temporal analysis of products reactor measurements, we studied the reactive removal of active oxygen present on Au/TiO2 catalysts after calcination at elevated temperatures （400 ＆#176;C） by CO pulses and its replenishment by O2 pulses at 80 ＆#176;C, focusing on the nature of the active oxygen species. In contrast to previous studies, which mainly focused on and clarified the nature of the active oxygen species for the catalytic CO oxidation, which is reversibly formed and replenished under typical reaction conditions, this study demonstrates that directly after calcina‐tion an additional oxygen species is present. This species is also active for the CO oxidation, but it is not or only very little formed under typical reaction conditions. Implications of these results on the mechanistic understanding of the CO oxidation on Au/TiO2, in particular on the role of different active oxygen species, will be discussed.展开更多
Alcalase hydrolyzed protein from Anchovy under controlled condition, and the hydrolysates were rich in active peptides. The peptide content was determined by TCA-biuret method, and amino acid was determined by Ninhydr...Alcalase hydrolyzed protein from Anchovy under controlled condition, and the hydrolysates were rich in active peptides. The peptide content was determined by TCA-biuret method, and amino acid was determined by Ninhydrin. The antioxidative activity of the hydrolysates was investigated by measuring the reducing ability, the inhibition of lipoxygenase activity, and antioxidative ability in linoleic acid oxidation system. The hydrolysates exhibited high antioxidative activity. In addition, the hydrolysates scavenged 58.38% on hydroxyl radical and 46.88% on superoxide radical.展开更多
We previously isolated a natural product, namely guaiazulene-2,9-dione showing strong antibacterial activity against Vibrio anguillarum, from a gorgonian Muriceides collaris collected in South China Sea. In this exper...We previously isolated a natural product, namely guaiazulene-2,9-dione showing strong antibacterial activity against Vibrio anguillarum, from a gorgonian Muriceides collaris collected in South China Sea. In this experiment, guaiazulene-2,9-dione was quantitatively synthesized with an optimized one-step bromine oxidation method using guaiazulene as the raw material. The key reaction condition including reaction time and temperature, drop rate of bromine, concentration of aqueous THF solution, respective molar ratio of guaiazulene to bromine and acetic acid, and concentration of guaiazulene in aqueous THF solution, were investigated individually at five levels each for optimization. Combined with the verification test to show the absolute yield of each optimization step, the final optimal condition was determined as: when a solution of 0.025 mmol m L-1 guaiazulene in 80% aqueous THF was treated with four volumes of bromine at a drop rate of 0.1 m L min-1 and four volumes of acetic acid at-5℃ for three hours, the yield of guaiazulene-2,9-dione was 23.72%. This was the first report concerning optimized one-step synthesis to provide a convenient method for the large preparation of guaiazulene-2,9-dione.展开更多
Reactive oxygen species(ROS)is widespread in living organisms.Under normal conditions,ROS remains at low concentrations to maintain normal cell function.Studies have found that the abnormal elevation of ROS levels in ...Reactive oxygen species(ROS)is widespread in living organisms.Under normal conditions,ROS remains at low concentrations to maintain normal cell function.Studies have found that the abnormal elevation of ROS levels in normal tissues is an important mechanism underlying the tumorigenesis.However,high concentrations of ROS also have toxic,genotoxic,and even apoptotic effects on tumor cells.ROS has become one of the important targets for cancer prevention and treatment.Natural products widely exist in nature and have a wide range of pharmacological activities,which can affect the function of ROS.In the present study,we reviewed the research progress of natural products in tumor prevention and treatment by regulating ROS level in recent years.展开更多
目的:探究右归丸对阿霉素诱导的肾病综合征(NS)大鼠的影响及其作用机制。方法:SD大鼠随机分为正常组、模型组、右归丸低、中、高剂量组和泼尼松组。模型组大鼠尾静脉注射阿霉素构建NS模型,右归丸低、中、高剂量组分别按生药2.8、5.6、11...目的:探究右归丸对阿霉素诱导的肾病综合征(NS)大鼠的影响及其作用机制。方法:SD大鼠随机分为正常组、模型组、右归丸低、中、高剂量组和泼尼松组。模型组大鼠尾静脉注射阿霉素构建NS模型,右归丸低、中、高剂量组分别按生药2.8、5.6、11.2 g·kg^(-1)·d^(-1)灌胃,泼尼松组以醋酸泼尼松6.3 mg·kg^(-1)·d^(-1)灌胃。各用药组连续给药6周,正常组及模型组灌服等体积生理盐水。BCA法检测24 h尿蛋白(24 h UP);全自动生化分析仪检测血清尿素氮(BUN)、肌酐(SCr)、白蛋白(ALB)、总胆固醇(TC)、甘油三酯(TG)水平;苏木素-伊红(HE)染色观察肾组织病理形态变化;试剂盒检测血清晚期氧化蛋白产物(AOPPs)、活性氧(ROS);蛋白免疫印迹法(Western blot)检测肾组织晚期糖基化终产物受体(RAGE)、核转录因子-κB(NF-κB)磷酸化水平、Wnt及β-连环蛋白(β-catenin)蛋白表达。结果:与正常组比较,模型组大鼠24 h UP、血清BUN、SCr、TC、TG、AOPPs、ROS水平均显著升高(P<0.01),ALB显著降低(P<0.01),且肾组织存在典型的病理性损伤,RAGE、磷酸化(p)-NF-κB、Wnt1及β-catenin蛋白表达均显著升高(P<0.01)。与模型组比较,右归丸低、中、高剂量组大鼠24 h UP、血清BUN、SCr、TC、TG、AOPPs、ROS水平均显著降低(P<0.01),ALB明显升高(P<0.01),肾组织损伤减轻,RAGE、p-NF-κB、Wnt1及β-catenin蛋白表达均显著降低(P<0.01),且呈剂量相关。结论:右归丸能够改善阿霉素诱导的NS大鼠肾损伤,其机制可能与降低AOPPs水平,抑制RAGE/ROS/NF-κB轴及Wnt/β-catenin信号活化相关。展开更多
基金supported by the High Technology Research and Development Program of China (No. 2006AA09Z438)the National Natural Science Foundation of China (No. 30871943).
文摘Fish skin collagen hydrolysates （FSCH） were prepared from walleye pollock （Theragra chalcogramrna） using a mixture of enzymes, namely trypsin and flavourzyme. The degree of hydrolysis of the skin collagen was 27.3%. FSCH was mainly composed of low-molecular-weight peptides and the relative proportion of 〈1000Da fraction was 70.6%. Free radical and oxygen species scavenging activities of FSCH were investigated in four model systems, including diphenylpicrylhy-drazyl radical （DPPH）, superoxide anion radical, hydroxyl radical and hydrogen peroxide model, and compared with that of a native antioxidant, reduced glutathione （GSH）. FSCH was also evaluated by water-absorbing and water-holding capacity. The results showed that FSCH was able to scavenge free radical and oxygen species significantly and to enhance water-absorbing and water-holding capacity remarkably. Therefore FSCH may have potential applications in the medicine and food industries.
文摘Applying quantitative temporal analysis of products reactor measurements, we studied the reactive removal of active oxygen present on Au/TiO2 catalysts after calcination at elevated temperatures （400 ＆#176;C） by CO pulses and its replenishment by O2 pulses at 80 ＆#176;C, focusing on the nature of the active oxygen species. In contrast to previous studies, which mainly focused on and clarified the nature of the active oxygen species for the catalytic CO oxidation, which is reversibly formed and replenished under typical reaction conditions, this study demonstrates that directly after calcina‐tion an additional oxygen species is present. This species is also active for the CO oxidation, but it is not or only very little formed under typical reaction conditions. Implications of these results on the mechanistic understanding of the CO oxidation on Au/TiO2, in particular on the role of different active oxygen species, will be discussed.
文摘Alcalase hydrolyzed protein from Anchovy under controlled condition, and the hydrolysates were rich in active peptides. The peptide content was determined by TCA-biuret method, and amino acid was determined by Ninhydrin. The antioxidative activity of the hydrolysates was investigated by measuring the reducing ability, the inhibition of lipoxygenase activity, and antioxidative ability in linoleic acid oxidation system. The hydrolysates exhibited high antioxidative activity. In addition, the hydrolysates scavenged 58.38% on hydroxyl radical and 46.88% on superoxide radical.
基金supported by National Natural Science Foundation of China (No. 21102136)Changjiang Scholars and Innovative Research Team in University (PCSIRT,No. IRT0944)
文摘We previously isolated a natural product, namely guaiazulene-2,9-dione showing strong antibacterial activity against Vibrio anguillarum, from a gorgonian Muriceides collaris collected in South China Sea. In this experiment, guaiazulene-2,9-dione was quantitatively synthesized with an optimized one-step bromine oxidation method using guaiazulene as the raw material. The key reaction condition including reaction time and temperature, drop rate of bromine, concentration of aqueous THF solution, respective molar ratio of guaiazulene to bromine and acetic acid, and concentration of guaiazulene in aqueous THF solution, were investigated individually at five levels each for optimization. Combined with the verification test to show the absolute yield of each optimization step, the final optimal condition was determined as: when a solution of 0.025 mmol m L-1 guaiazulene in 80% aqueous THF was treated with four volumes of bromine at a drop rate of 0.1 m L min-1 and four volumes of acetic acid at-5℃ for three hours, the yield of guaiazulene-2,9-dione was 23.72%. This was the first report concerning optimized one-step synthesis to provide a convenient method for the large preparation of guaiazulene-2,9-dione.
基金National Natural Science Foundation of China (Grant No. 81602729)。
文摘Reactive oxygen species(ROS)is widespread in living organisms.Under normal conditions,ROS remains at low concentrations to maintain normal cell function.Studies have found that the abnormal elevation of ROS levels in normal tissues is an important mechanism underlying the tumorigenesis.However,high concentrations of ROS also have toxic,genotoxic,and even apoptotic effects on tumor cells.ROS has become one of the important targets for cancer prevention and treatment.Natural products widely exist in nature and have a wide range of pharmacological activities,which can affect the function of ROS.In the present study,we reviewed the research progress of natural products in tumor prevention and treatment by regulating ROS level in recent years.
文摘目的:探究右归丸对阿霉素诱导的肾病综合征(NS)大鼠的影响及其作用机制。方法:SD大鼠随机分为正常组、模型组、右归丸低、中、高剂量组和泼尼松组。模型组大鼠尾静脉注射阿霉素构建NS模型,右归丸低、中、高剂量组分别按生药2.8、5.6、11.2 g·kg^(-1)·d^(-1)灌胃,泼尼松组以醋酸泼尼松6.3 mg·kg^(-1)·d^(-1)灌胃。各用药组连续给药6周,正常组及模型组灌服等体积生理盐水。BCA法检测24 h尿蛋白(24 h UP);全自动生化分析仪检测血清尿素氮(BUN)、肌酐(SCr)、白蛋白(ALB)、总胆固醇(TC)、甘油三酯(TG)水平;苏木素-伊红(HE)染色观察肾组织病理形态变化;试剂盒检测血清晚期氧化蛋白产物(AOPPs)、活性氧(ROS);蛋白免疫印迹法(Western blot)检测肾组织晚期糖基化终产物受体(RAGE)、核转录因子-κB(NF-κB)磷酸化水平、Wnt及β-连环蛋白(β-catenin)蛋白表达。结果:与正常组比较,模型组大鼠24 h UP、血清BUN、SCr、TC、TG、AOPPs、ROS水平均显著升高(P<0.01),ALB显著降低(P<0.01),且肾组织存在典型的病理性损伤,RAGE、磷酸化(p)-NF-κB、Wnt1及β-catenin蛋白表达均显著升高(P<0.01)。与模型组比较,右归丸低、中、高剂量组大鼠24 h UP、血清BUN、SCr、TC、TG、AOPPs、ROS水平均显著降低(P<0.01),ALB明显升高(P<0.01),肾组织损伤减轻,RAGE、p-NF-κB、Wnt1及β-catenin蛋白表达均显著降低(P<0.01),且呈剂量相关。结论:右归丸能够改善阿霉素诱导的NS大鼠肾损伤,其机制可能与降低AOPPs水平,抑制RAGE/ROS/NF-κB轴及Wnt/β-catenin信号活化相关。
