金花茶花浸提物与消化蛋白酶的相互作用

为探讨金花茶花浸提物对消化蛋白酶活性的影响及其作用机理,首先研究了金花茶花浸提物对消化蛋白酶活性的影响以及抑制动力学,其次采用荧光光谱法、紫外光谱法和圆二色谱法研究浸提物抑制消化蛋白酶活性的机制.结果表明,醇提物和水提物对胃蛋白酶(IC50分别为3.194和3.330 g/L;竞争抑制常数分别为4.518和7.641 ...     

防城金花茶叶片表型多样性及化学成分关联表型性状分析

目的 基于表型性状及化学成分, 分析防城金花茶叶片表型性状遗传多样性, 并采用相关分析法, 筛选与化学成分关联的表型性状。方法 通过叶片表型直接观察法和UPLC指纹图谱检测方法, 基于液相色谱峰数量和面积, 采用主成分分析、相关分析方法对防城金花茶遗传多样性及表型性状和化学成分关联性状进行品质评价。结果 防城金花茶叶片各表型性状遗传多样性程度均较高, 非数值型性状变异系数较高的为叶形(103.57%)、叶色(103.71%); 数值型性状变异系数较高的为叶片总数(54.19%)和产量(57.14%, )。每个株系所含的化学成分种类不尽相同, 多样性指数最低的为表儿茶素(0.310), 最高的为19-去甲睾酮(2.068), 相对于其他已知化学成分含量, 马钱苷含量最高。多数化学成分与叶尾和叶脉有显著相关性; 叶面积、叶柄及叶长宽比与极少数成分有相关性, 其中叶尾渐尖、叶脉浅且细脉少、叶面积较大者, 多数化学成分含量较高。结论 综上, 防城金花茶叶片遗传多样性丰富, 不同株系化学成分存在较大差异, 可通过叶面积大小、叶尾形状、叶脉深浅、细脉多少筛选多数化学成分含量高的株系。     

金花茶粉添加量对馒头品质及抗氧化性的比较分析

为探究小麦粉中添加金花茶粉对馒头品质及抗氧化活性的影响,以不同质量分数的0%、1%、2%、3%、4%的金花茶粉制作馒头,研究其对馒头面团特性、水分、膨胀度、比容、质构、色泽、感官、微观结构及其抗氧化性的影响。试验结果表明,随着金花茶粉添加量的增加,面团弹性模量G’始终大于粘性模量G’,tanδ值始终小于1,表现出较好的弹性性能。馒头水分含量先升后降,变化幅度0.8%。添加1%金花茶粉的膨胀度、质构特性最高（硬度40.41 N,弹性1.46 mm,咀嚼性25.10 MJ）。随着金花茶粉添加量增多馒头亮度呈显著下降趋势（P<0.05）,颜色加深。金花茶粉添加量在1%～2%时馒头的风味显著提高（P<0.05）。随着金花茶粉的添加,面团面筋结构由连续到断裂,由密集到空洞,内部空间结构遭到破坏。在抗氧化活性方面,DPPH自由基清除能力、还原能力和ABTS+自由基清除能力随着金花茶粉添加量增多显著提高,与对照组相比分别提高了63.33%、40.4%、59.57%。综合分析添加1%～2%金花茶粉对馒头品质就有一定改善。该研究结果为金花茶粉应用于馒头,提高其品质及营养价值,开发金花茶食品提...     

金花茶不同部位化学成分差异分析

目的 比较防普、越南、大叶金花茶叶、花两个部位化学指纹图谱差异, 分析其化学成分类型及部分有效成分含量差异, 为合理开发和利用金花茶提供依据。方法 采用超高效液相色谱法(ultra performance liquid chromatography, UPLC)建立防普、越南、大叶金花茶叶和花的化学指纹图谱; 利用中药色谱指纹图谱相似度评价系统(2012版)计算不同部位共有峰和相似度, 并分析各部位特征峰; 利用SPSS 23.0, 采用成对样本t检验, 对叶和花间不同化学成分含量差异进行比较。结果 在320和210 nm波长下, 防普金花茶叶和花的相似度分别为0.504、0.054; 越南金花茶叶和花的相似度分别为0.151、0.478; 大叶金花茶叶和花的相似度分别为0.069、0.748, 3个品种金花茶的叶和花相似度均较低。各部位不同化学成分含量结果显示：防普金花茶花中金丝桃苷、叶中二氢槲皮素含量最高 且花和叶中绿原酸、二氢槲皮素、水杨酸、芹菜素含量差异达到显著水平(Sig<0.05); 越南金花茶花中牡荆素、叶中水杨酸含量最高,且叶和花中绿原酸、牡荆素、水杨酸、芹菜素含量差异达到显著水平(Sig<0.05); 大叶金花茶花中牡荆素、叶中二氢槲皮素含量最高,且花和叶中没食子酸、表儿茶素含量差异达到显著水平(Sig<0.05)。结论 3个品种金花茶叶和花化学成分和含量均存在显著差异, 叶和花在药理活性和功效上各有侧重, 药用和食用过程中应根据实际情况筛选使用。     

黄酒对高脂饮食小鼠的肥胖指标及肠道菌群的影响

该实验研究了黄酒对高脂饮食小鼠体质量、总脂肪、摄食量、血脂及肠道菌群的影响。将60只6周龄无特定病原（SPF）级雄性C57BL/6J小鼠随机分为5组,空白对照组饲喂基础饲料,高脂对照组和黄酒高、中、低剂量组饲喂高脂饲料。连续灌喂120 d后,测定相关肥胖指标和肠道菌群的变化。结果表明,黄酒能够减少高脂饮食小鼠的摄食量,抑制小鼠脂肪堆积和体质量的增加;降低甘油三酯（TG）和高密度脂蛋白胆固醇（HDL-C）含量,提高低密度脂蛋白胆固醇（LDL-C）含量;物种α-多样性分析结果显示,黄酒能够改善高脂饮食小鼠肠道菌群多样性,提高狄氏副拟杆菌（Parabacteroides distasonis）含量。黄酒通过抑制高脂饮食小鼠食欲降低其体质量增加,通过调节肠道菌群比例从而改善小鼠血脂异常。     

Research progress on the regulation of oxidative stress by phenolics: the role of gut microbiota and Nrf2 signaling pathway

In recent years, the increase in high-calorie diets and sedentary lifestyles has made obesity a global public health problem. An unbalanced diet promotes the production of proinflammatory cytokines and causes redox imbalance in the body. Phenolics have potent antioxidant activity and cytoprotective ability. They can scavenge free radicals and reactive oxygen species, and enhance the activity of antioxidant enzymes, thus combating the body's oxidative stress. They can also improve the body's inflammatory response, enhance the enzyme activity of lipid metabolism, and reduce the contents of cholesterol and triglyceride. Most phenolics are biotransformed and absorbed into the blood after the action by gut microbiota; these metabolites then undergo phase I and II metabolism and regulate oxidative stress by scavenging free radicals and increasing expression of antioxidant enzymes. Phenolics induce the expression of genes encoding antioxidant enzymes and phase II detoxification enzymes by stimulating Nrf2 to enter the nucleus and bind to the antioxidant response element after uncoupling from Keap1, thereby promoting the production of antioxidant enzymes and phase II detoxification enzymes. The absorption rate of phenolics in the small intestine is extremely low. Most phenolics reach the colon, where they interact with the microbiota and undergo a series of metabolism. Their metabolites will reach the liver via the portal vein and undergo conjugation reactions. Subsequently, the metabolites reach the whole body to exert biological activity by traveling with the systemic circulation. Phenolics can promote the growth of probiotics, reduce the ratio of Firmicutes/Bacteroidetes (F/B), and improve intestinal microecological imbalance. This paper reviews the nutritional value, bioactivity, and antioxidant mechanism of phenolics in the body, aiming to provide a scientific basis for the development and utilization of natural antioxidants and provide a reference for elucidating the mechanism of action of phenolics for regulating oxidative stress in the body. © 2023 Society of Chemical Industry.     

Wallace melon juice fermented with Lactobacillus alleviates dextran sulfate sodium-induced ulcerative colitis in mice through modulating gut microbiota and the metabolism

Fermented foods have shown promise in preventing or treating ulcerative colitis (UC) via regulating intestinal flora and correcting metabolic disorders. However, the prevention effect of fermented Wallace melon juice (FMJ) on UC is unclear. In this study, the effects of FMJ on dextran sodium sulfate (DSS)-induced UC were investigated via 16S rRNA sequencing and non-targeted metabolomics. The results showed that FMJ was effective in alleviating the symptoms of UC, reducing histological damage and oxidative stress, decreasing the levels of pro-inflammatory cytokines. After FMJ treatment, the level of propionic acid, butyric acid, and valeric acid increased by 14.1%, 44.4%, and 52.4% compared to DSS-induced UC mice. Meanwhile, the levels of harmful bacteria such as Oscillospira, Bacteroidetes, and Erysipelotrichaceae and Clostridium decreased, while the levels of beneficial bacteria such as Akkermansia, Lactobacillus, and Bifidobacterium increased. Fecal metabolomics analysis identified 31 differential metabolites, which could regulate metabolic disorders in UC mice by controlling the primary bile acid biosynthesis, purine metabolism, and pantothenate and CoA biosynthesis pathway. Additionally, the abundances of butyric acid, bile acids, and pantothenic acid were positively correlated with Allobaculum, Bifidobacterium, and other beneficial bacteria (R² > 0.80, p < 0.01). The results indicated that FMJ played a role in regulating the structure of intestinal flora, which in turn helped in repairing metabolic disorders and alleviated colitis inflammation.     

Camel milk modulates the gut microbiota and has anti-inflammatory effects in a mouse model of colitis

Camel milk is a nutritionally rich food that shows anti-inflammatory, immune regulation, and gut microbiota maintenance properties. However, the relationship between camel milk and the intestinal microbiota during colitis is unclear. Herein, we evaluated the protective effect of camel milk in mice with colitis induced using dextran sodium sulfate. Our results showed that camel milk can prevent body weight loss and colon shortening, reduce the disease activity index, and attenuate colon tissue damage. Additionally, camel milk could reduce the overexpression of inflammatory factors, inhibit the apoptosis of intestinal epithelial cells, and promote the expression of claudin-1, occludin, and zonula occludens-1 proteins. Moreover, camel milk effectively regulated intestinal microbiota in mice with colitis by increasing the gut microbiota diversity, increasing the abundance of beneficial bacteria (such as g_norank_f_Muribaculaceae, and Lachnospiraceae_NK4A136_group), and reducing the number of harmful bacteria (Bacteroides, Escherichia-Shigella). In addition, camel milk increased the levels of intestinal short-chain fatty acids. The results of the present study demonstrated that via regulating the intestinal microbiota, maintaining intestinal barrier function, and inhibiting proinflammatory cytokines, camel milk can ameliorate dextran sodium sulfate–induced colitis.