驴乳抑制胰岛素抵抗形成与氨基酸代谢的相关性

目的探讨驴乳(donkeymilk,DM)抑制高脂饮食诱导的胰岛素抵抗形成与氨基酸代谢的相关性。方法将36只C57BL/6N小鼠随机分为空白对照(Con)组,高脂饮食(high fat diet, HFD)组和HFD+驴乳组。给予空白对照组小鼠普通饲料及生理盐水灌胃, HFD组给予高脂饲料及生理盐水灌胃, HFD+驴乳组给予高脂饲料,并且每天按0.1 mL/10 g驴乳灌胃。饮食和驴乳干预8周后,检测各组小鼠血糖血脂水平和胰岛素敏感性,采用超高效液相色谱-串联质谱测定小鼠血浆靶标氨基酸含量,结合SIMCA-P软件对氨基酸数据进行PLS-DA分析,并分析变化的靶标氨基酸与血糖血脂水平的相关性。结果高脂饮食诱导8周,与Con组小鼠相比,HFD组小鼠体重、随机血糖(glucose, GLU)、总胆固醇(total cholesterol, TC)水平、口服葡萄糖耐量(oral glucose tolerancetest,OGTT)曲线下面积、胰岛素耐量曲线下面积和空腹血清胰岛素水平显著升高(P0.05),胰岛素敏感指数下降(P0.05)。与HFD组相比, HFD+驴乳组体重、GLU、TC和甘油三酯(triglyceride, TG)水平、OGTT曲线下面积显著降低(P0.05)。与空白对照组小鼠比较,HFD组小鼠血清中丙氨酸、半胱氨酸、脯氨酸、甲硫氨酸含量升高,赖氨酸含量降低(P0.05);与HFD组比较,HFD+驴乳组中的半胱氨酸含量显著降低(P0.01)。PLS-DA分析结果显示驴乳给予后小鼠血清氨基酸代谢谱较模型组发生了显著变化。Pearson相关分析显示,脯氨酸、甲硫氨酸和半胱氨酸分别与空腹血糖(fasting blood glucose, FBG)、GLU、TC水平呈显著性正相关(P0.05)。结论驴乳能够延缓高脂饮食诱导小鼠胰岛素抵抗的发生,并且驴乳能够影响胰岛素抵抗小鼠的血清氨基酸代谢谱,被改变的半胱氨酸、脯氨酸、甲硫氨酸的代谢与胰岛素抵抗的发生发展密切相关。     

Consumption of barley β‐glucan ameliorates fatty liver and insulin resistance in mice fed a high‐fat diet

Consumption of a diet high in barley β‐glucan (BG) has been shown to prevent insulin resistance. To investigate the mechanism for the effects of barley BG, three groups of male 7‐wk‐old C57BL/6J mice were fed high‐fat diets containing 0, 2, or 4% of barley BG for 12 wk. The 2% BG and 4% BG groups had significantly lower body weights compared with the 0% BG group. The 4% BG group demonstrated improved glucose tolerance and lower levels of insulin‐resistance index and glucose‐dependent insulinotropic polypeptide. Consumption of the BG diet decreased hepatic lipid content. Mice on the BG diet also demonstrated decreased fatty acid synthase and increased cholesterol 7α‐hydroxylase gene expression levels. The BG diet promoted hepatic insulin signaling by decreasing serine phosphorylation of insulin receptor substrate 1 and activating Akt, and it decreased mRNA levels of glucose‐6‐phosphatase and phosphoenolpyruvate carboxykinase. In summary, consumption of BG reduced weight gain, decreased hepatic lipid accumulation, and improved insulin sensitivity in mice fed a high‐fat diet. Insulin signaling enhanced due to the expression changes of glucose and lipid metabolism genes by BG consumption. Consumption of barley BG could be an effective strategy for preventing obesity, insulin resistance, and the metabolic syndrome.     

植物花青素通过JNK信号通路抗肿瘤机制研究进展

文章综述了JNK信号通路的组成及活化机制,总结了植物花青素通过该信号通路抑制乳腺癌、前列腺癌、肝癌等恶性肿瘤发生、增殖、侵袭和凋亡的能力,以期为植物花青素应用于功能食品和药品的开发提供依据。     

Modulatory effects of yerba maté (Ilex paraguariensis) on the PI3K‐AKT signaling pathway

The aim of this study was to evaluate the effects of yerba maté (YM) extract on the phosphatidylinositol 3‐kinase (PI3K)‐AKT signaling pathway in vivo. The mice were introduced to either standard‐ or high‐fat diet (HFD). After 8 weeks on an HFD, mice were randomly assigned to one of the two treatment conditions, water or yerba maté extract at 1.0 g/kg. After treatment, glucose blood level and hepatic insulin response were evaluated. Liver tissue was examined to determine the mRNA levels using the PI3K‐AKT PCR array. The nuclear translocation of forkhead box O1 (FOXO1) was determined by an electrophoretic mobility‐shift assay. Our data demonstrated that yerba maté extract significantly decreased the final body weight, glucose blood levels, and insulin resistance of mice. Molecular analysis demonstrated that an HFD downregulated Akt2, Irs1, Irs2, Pi3kca, Pi3kcg, and Pdk1; after yerba maté treatment, the levels of those genes returned to baseline. In addition, an HFD upregulated Pepck and G6pc and increased FOXO1 nuclear translocation. The intervention downregulated these genes by decreasing FOXO1 nuclear translocation. The results obtained demonstrate for the first time the specific action of yerba maté on the PI3K‐AKT pathway, which contributed to the observed improvement in hepatic insulin signaling.     

高效液相色谱法测定免疫功能型保健食品中8种功效成分

目的 建立高效液相色谱法同时测定免疫功能型保健食品中8种功效成分(左旋肉碱、L-茶氨酸、天麻素、吡啶甲酸铬、咖啡因、淫羊藿苷、菊苣酸、10-羟基-α-癸烯酸)的分析方法.方法 样品用70％甲醇超声提取,采用C18色谱柱分离,以甲醇-磷酸二氢钾(0.1％磷酸)水溶液为流动相,梯度洗脱,外标法定量.结果 左旋肉碱、L-茶氨...     

Variability and the genotypic effect on antioxidant activity,total phenolics,carotenoids and ascorbic acid content in seventeen natural population of Seabuckthorn (Hippophae rhamnoides L.) from trans-Himalaya

Seventeen natural population of Seabuckthorn (SBT), which comprised 187 plants from trans-Himalaya, were studied to find out variability and genotypic effect on total phenolic content (TPC), total antioxidant capacity (TAC), ascorbic acid and carotenoids content in fruit pulp. The fruits were found to be rich in TPC ranging from 964 to 10,704 mg gallic acid equivalent/100 g. The free radical-scavenging activity in terms of inhibitory concentration (IC₅₀) ranged from 0.7 to 9.1 mg/ml and ferric reducing antioxidant potential (FRAP) from 180 to 1355 FeSO₄·7H₂O μg/ml. The ascorbic acid and carotenoids content ranged from 56 to 3909 mg/100 g and 0.1–14.4 mg/100 g, respectively. A variation of 1–11 fold in TPC, 1–14 folds in IC₅₀ by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and 1–8 fold in ferric reducing antioxidant potential, 1–70 fold in ascorbic acid content and 1–206 fold in carotenoid content among the examined fruit across 17 populations underlines the important role played by genetic background and the geographical location for determining the health promoting compounds. Significant correlation was observed between TPC, IC₅₀, FRAP, carotenoids, ascorbic acid, fruit lightness (L*) and plant height. Among the 20 morphological traits studied, fruit colour and plant height showed positive correlation with the health promoting compounds.     

Nutritional evaluation and antioxidant activity of sesame sprouts

Sesame sprouts are consumed as vegetables in Asian folk. In this study, the nutritional evaluation and antioxidant activity of sesame sprouts were investigated. As seeding days progressed, the free amino acids, γ-aminobutyric acid and total phenolic compounds in the sprouts were rapidly increased while sesamin was reduced. Although a fatty acid composition analysis showed that sesame sprouts were abundant in unsaturated fatty acids, the crude fat content was gradually reduced during sprout growth. In the antioxidant assays, it was found that the DPPH radical scavenging activity and the reducing power of the sprouts increased as the seeding days progressed, which was positively related to the total phenolic content. Sesame sprouts can be recommended for functional ingredients, as well as being an excellent dietary source of natural antioxidants.     

Improvement of insulin resistance by Hon-Chi in fructose-rich chow-fed rats

In an attempt to develop new substances for handling insulin resistance, the effect Hon-Chi was examined on insulin resistance induced by fructose-rich chow in rats. Mandarin Hon-Chi is red yeast rice fermented with Monascus pilous and Monascus purpureus. Single oral administration of Hon-Chi for 90 min decreased the plasma glucose in a dose-dependent manner in rats, which had received four-week fructose-rich chow. The insulin action on glucose disposal rate using the glucose–insulin index, and the value of the areas under the curve of glucose and insulin during the intraperitoneal glucose tolerance test were measured. Oral administration (three times daily for three-days) of Hon-Chi into rats, which received four-week fructose-rich chow, reversed the elevated value of glucose-insulin index, indicating Hon-Chi has an ability to improve insulin resistance. The time for the loss of plasma glucose lowering response to tolbutamide in fructose-rich chow-fed rats was markedly delayed by the repeated treatment of Hon-Chi, as compared to the vehicle-treated group. This provided the supportive data that oral administration of Hon-Chi could delay the development of insulin resistance in rats. Increase of insulin sensitivity by Hon-Chi was further identified using the plasma glucose lowering action of exogenous insulin in streptozotocin-induced diabetic rats (STZ-diabetic rats). Oral administration of Hon-Chi at 150 mg/kg three times daily into STZ-diabetic rats caused an increase in the responses to exogenous insulin 15-days later. The obtained results suggest that oral administration of Hon-Chi has the ability to improve insulin sensitivity and delay the development of insulin resistance in rats, which may be used as an adjuvant therapy to patients with insulin resistance.