高效液相色谱法测定葡萄皮和葡萄籽中白藜芦醇的含量

测定不同品种葡萄皮和葡萄籽及酿酒后的葡萄皮渣中白藜芦醇的含量。应用乙腈 -水 (2 6∶74 )为流动相 ,检测波长 (λ)为 30 3nm ,柱温为 35℃ ,色谱柱 :SUPELCOSILTMLC 18(2 5 0mm× 4 6mm ,5 μm)。结果显示 ,葡萄皮中的白藜芦醇含量高于葡萄籽 ;不同品种葡萄皮中白藜芦醇含量差异较大 ,琐琐葡萄最低为0 985 0 μg g ,红克里米斯克葡萄最高为 15 4 195 μg g;同一产地同一品种葡萄皮中白藜芦醇含量依次为酿酒后的葡萄皮 >新鲜葡萄皮 >陈旧葡萄皮 ,且差异有统计学意义     

异氟醚预处理对大鼠肾缺血再灌注损伤的影响

目的观察异氟醚预处理对大鼠肾缺血再灌注（ischemia-reperfusion,I／R）损伤的影响,并探讨肿瘤坏死因子-α（TNF-α）在其中的作用。方法健康成年雄性SD大鼠36只,随机分成假手术组（s组）,缺血再灌注组（I／R组）和异氟醚预处理组（Iso＋I／R组）,每组各12只。S组进腹后仅分离韧带不阻断血流;I／R,组行肾脏缺血45rain,再灌注2h;Iso＋I／R组吸人1．5％（1MAC）异氟醚30min,停止吸入10rain后行I／R。在再灌注2h后测定血清尿素氮（BUN）和肌酐（cr）的含量,采用双抗体夹心酶联免疫吸附试验（ELISA法）测定。肾组织中TNF-α的浓度,同时取肾组织进行HE染色观察病理学改变。结果（1）与S组比较,I／R组和Iso＋I／R组血清BUN和cr表达水平、肾组织中TNF-α浓度均升高[BUN：（17．69±0．99）mmol／LV8（8．37±1．12）mmol／L,t=-23．55,P〈0．01;（12．26±1．11）mmol／Lvs（8．37±1．12）mmol／L,t=-19．09,P〈0．01;Cr：（103．22±13．42）μmol／Lvs（71．48±8．59）μmol／L,t=-21．45,P〈0．01;（86．51±11．49）μmol／Lvs（71．48±8．59）μmol／L,t=-9．87,P〈0．01;TNF-α：（0．51±0．07）rig／mlvs（0．43±0．00）ng／ml,t=-5．79,P〈0．01;（0．47±0．03）ng／Ⅱdvs（0．43±0．00）ng／ml,t=-8．86,P〈0．01]。（2）Iso＋I／R组血清BUN和Cr表达水平、肾组织中TNF-α浓度的升高幅度均小于I／R组[BUN：（12．26±1．11）mmol／LVS（17．69±0．99）retool／L,t=15．67,P〈0．01;Cr：（86．51±11．49）μmol／Lvs（103．22±13．42）μmol／L,t=6．68,P〈0．01;TNF-α：（0．47±0．03）ng／mlvs（0．51±0．07）ng／ml,t=2．61,P〈0．05]。（3）I／1t组、Iso＋I／R组。肾小管评分较S组升高[（17．26±1．45）VS（0．00±0．00）,t=-72．38,P〈0．01;（12．69±1．83）VS（0．00±0．00）,t=-39．53,P〈0．01]。Iso＋I／lt组肾小管评分较I／R组下降[（12．69±1．83）vs（17．26±1．45）,t=19．87,P〈0．01]。结论1．5％异氟醚预处理30min可减轻大鼠肾缺血再灌注损伤,其部分机制可能与下调肾组织中TNF-α水平有关。     

他克莫司预处理对大鼠肾缺血再灌注损伤中Bcl2蛋白表达的影响

目的探讨他克莫司预处理后对大鼠肾缺血再灌注损伤中Bcl₂蛋白表达的影响。方法选用Wistar大鼠60只,随机分为三组:假手术组、对照组、实验组,每组20只。假手术组仅开腹、分离肾动脉,不阻断血流;对照组于缺血前6h经尾静脉注射生理盐水1ml;实验组于缺血前6h经尾静脉注射他克莫司（0.5mg/kg）。到达设定的不同灌注时间点取血及肾脏标本,全自动生化分析仪测定血清肌酐（Cr）、尿素氮（BUN）;免疫组化检测肾组织B细胞淋巴瘤（Bcl-2）;HE染色分析肾组织病理损伤程度。结果在再灌注2h、6h和24h时,实验组的Cr、BUN水平显著低于对照组（p<0.05）,而Bcl-2免疫反应强度显著高于对照组（p<0.05）。HE染色光镜下对照组的肾小管及肾小管上皮细胞病变程度重;实验组的肾小管及肾小管上皮细胞病变程度明显减轻;假手术组肾小管及肾小管上皮细胞未见明显改变。结论小剂量他克莫司预处理可以减轻大鼠肾缺血再灌注损伤,可能是通过增加肾脏bcl-2蛋白的表达,达到改善大鼠肾缺血再灌注损伤。     

Flavonoids from grape seeds prevent increased alcohol-induced neuronal lipofuscin formation

Aims: In a previous study, we found that prolonged oxidativestress produced by chronic ethanol consumption leads to an increasedformation of lipofuscin in hippocampal and cerebellar neurons.This pigment is an end-result of lipid peroxidation. Flavanols,which abound in the human diet, are known to exert a powerfulin-vitro antioxidant action. Therefore, to evaluate whetherthese compounds might display beneficial effects in the ratbrain, we examined whether or not these natural antioxidantswould impede neuronal ethanol-induced lipofuscin accumulation.Methods: Adult rats were fed for 6 months either with 20% ethanolsolution or with the same solution to which a mixture of grapeseed catechins and oligomeric procyanidins (200 mg/l) was added.Controls ingested either tap water or water supplemented withthe antioxidant compound. The total amount of lipofuscin inthe hippocampal CA1 and CA3 pyramids and in the cerebellar Purkinjecells was estimated by applying unbiased stereological methods.The mean volume of the neurons was estimated using the nucleatorand the volumetric density of lipofuscin was calculated by pointcounting. Results: Flavanols prevented the accumulation of neuronallipofuscin in the animals submitted to ethanol feeding (i.e.under conditions of increased oxidative stress) but not in thewater-drinking controls. The neuronal volume did not alter amongthe groups studied. Conclusions: Data obtained show that consumptionof flavanols can reduce the effects of oxidative activity broughtabout by alcohol consumption, indicating that these compoundsmight display neuronal beneficial effects under oxidative stress.     

硫酸镁对小鼠肾缺血再灌注损伤保护作用

目的 观察硫酸镁对小鼠肾缺血再灌注损伤的抗氧化保护作用.方法 雄性小鼠随机分为假手术组、模型组和硫酸镁高、低剂量(120、60 mg/kg)组,无创动脉夹夹闭左肾蒂45 min和再灌注3 h制备急性肾缺血再灌注损伤模型,检测肾脏指数、血清尿素氮(BUN)和肌酐含量、肾组织丙二醛(MDA)含量以及超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)活力,HE染色观察肾组织学变化.结果 硫酸镁高、低剂量组小鼠肾指数分别为(0.72±0.05)和(0.74±0.07)、血清BUN含量为(12.36±2.24)和(15.58±1.92)mmol/L、血清肌酐水平为(98.23±4.37)和(114.63±6.24)μmol/L、肾组织MDA含量为(2.11±0.24)和(2.27±0.21)nmol/(mg.prot),肾组织SOD活力为(4.03±0.68)和(3.51±0.58)U/(mg.prot),硫酸镁高剂量组肾组织GSH-Px活力为(323.90±23.50)U/(mg.prot),与模型组比较,差异均有统计学意义(P<0.05),且肾组织病理变化较轻.结论 硫酸镁对小鼠急性肾缺血再灌注损伤具有保护作用,其机制可能与抑制脂质过氧化反应有关.     

复方丹参对家兔肾缺血-再灌注损伤的影响

目的 探讨复方丹参药物对肾缺血再灌注损伤的保护作用.方法 取健康大耳自家兔共34只,随机分成A、B两组,分别夹闭右肾动脉缺血20 min(A组)及30 min(B组)后开放,产生再灌注损伤.在开放后30 min、60 min、90 min、120 min分别取血测定血清丙二醛(malondialdehyde,MDA)含量.A、B两组均设实验组及对照组.实验组给予复方丹参液,对照组给予5%葡萄糖液.结果 当缺血时间为20 min时,实验组与对照组比较未出现统计学意义(P>0.05),缺血时间为30 min时,实验组血清MDA含量明显低于对照组(P<0.05).结论 预防性应用复方丹参药物对肾缺血再灌注损伤有保护作用.     

Quality assessment of commercial dietary antioxidant products from Vitis vinifera L. grape seeds

Phenolic preparations from Vitis vinifera L. grape seeds are products commonly used in the formulation of dietary antioxidant supplements. In this article, we used a methodology (the oxygen radical absorbance capacity, ORAC) to evaluate the in vitro antioxidant capacity of commercial dietary grape seed products and studied the relationship of the antioxidant capacity with the phenolic composition of these products. The ORAC value of the different brands of commercial products studied (n = 16) varied from 2.71 to 26.4 micromol Trolox equivalents/mg (approximately equal to 10-fold difference). For four of these products, the batch-to-batch ORAC variation, expressed as a coefficient of variation of the mean, was 10.5% (n = 6), 13.1% (n = 3), 19.4% (n = 4), and 7.8% (n = 4). Analysis of monomeric and oligomeric flavan-3-ols by liquid chromatography-diode array detection (LC-DAD)/electrospray-mass spectrometry and procyanidins by thiolysis-LC-DAD also revealed large differences among the commercial grape seed products. Moreover, the ORAC value could be fitted to a regression model using variables from contents of individual phenolic compounds and procyanidins. The product-to-product and batch-to-batch variation in ORAC values and flavan-3-ol composition found among the commercial products studied demonstrated that they are poorly standardized, resulting in inconsistent composition and biological activity.     

Inhibitory effects of grape seed extract on lipases

OBJECTIVE: The aim of the present study was to assess the effects of grape seed extract (GSE) on the fat-metabolizing enzymes pancreatic lipase, lipoprotein lipase, and hormone-sensitive lipase in vitro and evaluate its potential application as a treatment for obesity. METHODS: Crushed grape seeds were extracted in ethanol, and the extract was assayed for the measurement of inhibitory effects on pancreatic lipase and lipoprotein lipase activities and on lipolysis of 3T3-L1 adipocytes. RESULTS: The GSE rich in bioactive phytochemicals showed inhibitory activity on the fat-metabolizing enzymes pancreatic lipase and lipoprotein lipase, thus suggesting that GSE might be useful as a treatment to limit dietary fat absorption and the accumulation of fat in adipose tissue. The observed reduction in intracellular lipolytic activity of cultured 3T3-L1 adipocytes may reduce the levels of circulating free fatty acids that have been linked to insulin resistance in obese patients. CONCLUSION: The GSE rich in compounds that inhibit lipases may provide a safe, natural, and cost-effective weight control treatment.     

Biological effects of hydrolyzed quinoa extract from seeds of Chenopodium quinoa Willd

An extract from seeds of Chenopodium quinoa Willd. (quinoa), termed hydrolyzed quinoa (HQ), was obtained by enzymatic hydrolysis from seeds of the quinoa variety BRS-Piabiru. Analysis of the physical and chemical properties of quinoa and HQ showed that the hydrolyzed extract is rich in essential amino acids, particularly those with branched chains (leucine, isoleucine, and valine). In addition, we evaluated the biological effects of HQ, particularly the toxicological potential. For this purpose, male Wistar rats were assigned randomly to four groups: (1) sedentary supplemented group, which received HQ (2,000?mg/kg); (2) sedentary control group, non-supplemented; (3) exercised supplemented group (i.e., rats subjected to aerobic physical exercise that received HQ [2,000?mg/kg]); and (4) exercised control group (i.e., rats subjected to aerobic physical exercise, non-supplemented). After 30 days, all groups were analyzed for levels of serum glucose, cholesterol, triacylglycerol, total protein, albumin, uric acid, and urea and activities of the enzymes alkaline phosphatase, aspartate aminotransferase, and alanine aminotransferase. Body weight gain, dietary intake, and lipid deposition were also analyzed. The results showed no hepatic and renal toxicity of HQ. Moreover, decreased food intake, body weight, fat deposition, and blood triacylglycerol level were observed in the supplemented groups (sedentary and exercised supplemented groups). These results suggest a potential use of HQ in human nutrition.     

Acute renal failure caused by plant extract

The authors review the case of a 30 years old female patient presenting with a 48 hours-standing anuria, who permanently used products of grist of a virtuous plant, Guarana and occasionally used a parenteral non-steroid painkiller. The clinical history and laboratory results showed acute renal and hepatic failure. The histological picture of the renal biopsy specimen verified an acute tubular necrosis. After temporary dialysis treatment, her renal function recovered progressively with compensatory polyuria. The authors would like to draw the attention to the risks of the use of over-the-counter marketed paramedicinal products, per se or in combination with pharmaceutically registered products, sold in pharmacies and nutrition supplement stores.     

Beneficial effects of grape seed extract on malondialdehyde-modified LDL

Following consecutive 12-wk administration of tablets containing 0, 200 or 400 mg grape seed extract (calculated as proanthocyanidin) to 61 healthy subjects with LDL cholesterol (LDL-C) levels of 100 to 180 mg/dL, effects of such treatment compared to administration of placebo tablets on malondialdehyde-modified LDL (MDA-LDL), representing one oxidized type of LDL, were investigated by a single blind method. MDA-LDL level in the 200 mg (calculated as proanthocyanidin) group was significantly (p = 0.008) reduced compared to the basal level, 12 wk after the start of administration. In the 400 mg (calculated as proanthocyanidin) group, a significant decrease in MDA-LDL level compared to the basal level was found 6 and 12 wk after the start of administration (6 wk: p = 0.015, 12 wk: p = 0.009). Subjects with high levels of MDA-LDL/ApoB (MDA-LDL/ApoB > or = 100 mU/mL) in the 200 mg group showed significantly (p = 0.011) reduced MDA-LDL levels at 12 wk after the start of administration. In the 400 mg group, significant decreases in MDA-LDL level compared to the basal level were seen 6 and 12 wk after the start of administration (6 wk: p = 0.001, 12 wk: p < 0.001); and at week 6, significantly (p = 0.048) lower values were observed compared to those in patients who took placebo tablets (0 mg proanthocyanidin). In subjects demonstrating the least body weight changes during the test period (less than +/- 1.0 kg) in the 400 mg group, there was an increasing trend (p = 0.088) in adiponectin levels 12 wk after the start of treatment. These results suggested that tablets containing grape seed extract exerted reducing effects on oxidized LDL, and might be useful in preventing lifestyle-related diseases such as arteriosclerosis.     

Chemical characterisation of Malvar grape seeds (Vitis vinifera L.) by ultrafiltration and RP-HPLC-PAD-MS

A combination of fast ultrafiltration clean-up procedure and enhanced resolution RP-HPLC-PAD-MS analytical technique is proposed for the characterisation of low molecular mass extractable phytochemicals from Malvar grape seeds (Vitis vinifera L.). This methodology offers satisfactory resolution of the main procyanidin dimers and some trimers and tetramers. Thirty-nine peaks were identified. Seventeen of them contained 17 unambiguously identified compounds: 3 flavan-3-ol monomers (C, EC and ECG), 6 procyanidin dimers (B₁, B₂, B₃, B₄, B₅ and B₆), 1 procyanidin trimer (C₁), 1 procyanidin tetramer ([EC-(4α-8)-EC-(4α-8)-EC-(4α-8)-EC]), 4 hydroxybenzoic derivatives (gallic and protocatechuic acids, protocatechuic aldehyde and methyl gallate*), 1 amino acid (tryptophan)* and ellagic acid*. The remaining 22 peaks, and 1 of the first 17 contained 26 compounds which were tentatively identified as: 2 procyanidin dimers (A- and B-type), 7 trimers, 3 tetramers, 7 monogalloylated dimers, 2 monogalloylated trimers and 1 digalloylated dimer, besides 1 gallotannin, 1 dihydroflavonol* and 2 ellagitannins, some of them described for first time in V. vinifera species. Flavan-3-ols represented 62.4% of all grape seed constituents, absorbing at 280 nm, whereas the non-flavan-3-ol species accounted for more than one-third of the total extractable grape seed constituents.     

Protective effect of aqueous garlic extract against renal ischemia/reperfusion injury in rats

Oxygen free radicals are important components involved in pathophysiological tissue alteration observed during ischemia/reperfusion (I/R). This study was designed to determine the possible protective effect of aqueous garlic extract (AGE) on renal I/R injury. Wistar albino rats were unilaterally nephrectomized and subjected to 45 minutes of renal pedicle occlusion followed by 6 hours of reperfusion. AGE (1 mL/kg, i.p., corresponding to 500 mg/kg) or vehicle was administered twice: 15 minutes prior to ischemia and immediately before the reperfusion period. At the end of the reperfusion period, rats were killed by decapitation. Kidney samples were taken for histological examination or determination of levels of free radicals; renal malondialdehyde (MDA), an end product of lipid peroxidation; glutathione (GSH), a key antioxidant; and myeloperoxidase (MPO) activity, an index of tissue neutrophil infiltration. Renal tissue collagen content, as a fibrosis marker, was also determined. Creatinine and urea concentrations in blood were measured for the evaluation of renal function. The results revealed that I/R-induced nephrotoxicity, as evidenced by increases in blood urea and creatinine levels, was reversed by AGE treatment. The levels of free radicals, as assessed by the nitro blue tetrazolium test, were increased. Moreover, the decrease in GSH levels and the increases in MDA levels and MPO activity induced by I/R indicated that renal injury involves free radical formation. Treatment of rats with AGE (1 mL/kg) restored the reduced GSH levels, while it decreased free levels of radicals and MDA as well as MPO activity. Collagen contents of the kidney tissues increased by I/R were reversed back to the control levels with AGE. Since AGE administration reversed these oxidant responses and improved renal function and damage at the microscopic level, it seems likely that AGE protects kidney tissue against I/R-induced oxidative damage.     

运动预适应对大鼠心肌相对缺血再灌注损伤的延迟保护作用

目的探讨运动预适应(EP)对大鼠心肌相对缺血再灌注(I/R)损伤的延迟保护作用。方法实验分在体实验和离体实验,各32只Wistar大鼠随机分为4组正常对照组(CN)、相对缺血再灌注组(IR)、运动预适应组(EP)和运动预适应+相对缺血再灌注组(EI)。测定指标(1)在体实验大鼠血清丙二醛(MDA)含量、3级负荷运动时间;(2)离体实验大鼠心功能指标(左室发展压、心率、心率脉压乘积)、冠脉流出液MDA含量等。结果(1)在体实验EI组3级负荷运动时间[(71.67±9.00)min]明显高于IR组[(58.67±4.13)min],差异有统计学意义(P<0.05);EP组和EI组血清MDA含量[分别为(107.00±35.99)、(152.23±29.94)μmol/L]均明显低于IR组[(313.20±43.40)μmol/L],差异有统计学意义(P<0.05)。(2)离体实验CN组和EP组再灌注期的心率脉压乘积相对平稳,EI组在30min达到高峰,基本能恢复到缺血前水平,而IR组有所恢复,但仍明显低于缺血前水平,EI组心功能恢复率较IR组明显升高;EP组和EI组再灌注前后冠脉流出液MDA含量差值分别为(0.34±0.24)、(0.41±0.26)μmol/L,均明显低于IR组[(1.27±0.52)μmol/L],差异有统计学意义(P<0.05)。结论EP对大鼠心肌相对I/R损伤有明显的延迟性保护作用。     

Influence of glycine on intestinal ischemia-reperfusion injury

BACKGROUND: It has been reported that glycine may protect donor small intestine against hypothermic ischemia before transplantation. This is consistent with the documented role of glycine as a natural cytoprotectant. OBJECTIVE: Using an in vivo rodent model, we sought to determine whether exposure to a 20% glycine solution reduces the extent of warm ischemia-reperfusion injury. METHODS: Wistar rats (n = 50) underwent laparotomy. A baseline group did not receive any further intervention. The remaining animals had cannulation of the aorta before the initiation of intestinal ischemia (30 minutes) followed by reperfusion (30 minutes). Using a factorial design, rats were randomized to receive local tissue perfusion with either normal saline or a 20% glycine solution during either the preischemia or the prereperfusion phase. Standardized segments of small intestine were removed at the end of the study period to determine the extent of ischemia-reperfusion injury. RESULTS: Perfusion with 20% glycine increased mucosal protein content (p < .05), increased mucosal DNA content (p < .05), reduced intestinal myeloperoxidase activity (p < .05), and maintained mucosal glutaminase activity. This was true regardless of whether glycine was administered during the preischemia phase or the prereperfusion phase. CONCLUSIONS: Local perfusion with 20% glycine can diminish warm ischemia-reperfusion injury to the rat small intestine in an in vivo model. The role of glycine supplementation should be evaluated in situations where hemodynamic instability may be responsible for breakdown in the gut barrier.     

葡萄籽提取物抗实验性动脉粥样硬化作用及其机理研究

为探讨葡萄籽提取物抗实验性动脉粥样硬化作用及机理 ,将 5 0只动脉粥样硬化敏感株近交系C5 7BL 6J小鼠 ,随机分为正常对照组、高脂模型组、葡萄籽提取物低、高剂量组和药物对照组 ,正常对照组和高脂模型组 ,每日分别给予普通饲料和高脂饲料 ,葡萄籽提取物组和药物对照组 ,在每日给予高脂饲料的同时 ,分别添加葡萄籽提取物 (0 2mg g、0 6mg g体重 )和普托罗考片 (0 2mg g体重 ) ,实验至第 2 1周末 ,眼球放血处死小鼠 ,检测血清氧化型低密度脂蛋白 (OX LDL)、细胞粘附因子 1(ICAM 1)和一氧化氮 (NO)含量 ,同时取主动脉作病理形态学观察。结果发现 ,葡萄籽提取物组 ,血清OX LDL和ICAM 1水平均高于正常对照组 ,但明显低于高脂模型组 ,血清NO水平 ,则低于正常对照组而高于高脂模型组。观察主动脉部位的形态显示 ,葡萄籽提取物组其血管壁增厚程度、玻璃样改变和泡沫细胞数量均轻于模型组 ,高剂量组效果为佳 ,但仍重于正常对照组。实验结果提示 ,葡萄籽提取物具有减缓C5 7BL 6J小鼠动脉粥样硬化形成的作用 ,这可能与阻抑OX LDL、ICAM 1含量升高减低对血管内皮细胞损伤及保护血管内皮功能等作用有关     

Effect of dietary supplementation of grape skin and seeds on liver fibrosis induced by dimethylnitrosamine in rats

Grape is one of the most popular and widely cultivated fruits in the world. Although grape skin and seeds are waste product of the winery and grape juice industry, these wastes contain large amounts of phytochemicals such as flavonoids, phenolic acids, and anthocyanidins, which play an important role as chemopreventive and anticancer agents. We evaluated efficacies of grape skin and seeds on hepatic injury induced by dimethylnitrosamine (DMN) in rats. Treatment with DMN significantly increased levels of serum alanine transaminase, aspartate transaminase, alkaline phosphatase, and bilirubin. Diet supplementation with grape skin or seeds (10% daily for 4 weeks) prevented these elevations. The grape skin and seeds also restored serum albumin and total protein levels, and reduced the hepatic level of hydroxyproline and malondialdehyde. Furthermore, grape skin and seeds reduced DMN-induced collagen accumulation, as estimated by histological analysis of liver tissue stained with Sirius red. Grape skin and seeds also reduced hepatic stellate cell activation, as assessed by α-smooth muscle actin staining. In conclusion, grape skin and seeds exhibited in vivo hepatoprotective and antifibrogenic effects against DMN-induced liver injury, suggesting that grape skin and seeds may be useful in preventing the development of hepatic fibrosis.     

Antioxidant rich grape pomace extract suppresses postprandial hyperglycemia in diabetic mice by specifically inhibiting alpha-glucosidase

Background

Postprandial hyperglycemia is an early defect of type 2 diabetes and one of primary anti-diabetic targets. Treatment of postprandial hyperglycemia can be achieved by inhibiting intestinal α-glucosidase, the key enzyme for oligosaccharide digestion and further glucose absorption. Grape pomace is winemaking byproduct rich in bioactive food compounds such as phenolic antioxidants. This study evaluated the anti-diabetic potential of two specific grape pomace extracts by determining their antioxidant and anti-postprandial hyperglycemic activities in vitro and in vivo.

Methods

The extracts of red wine grape pomace (Cabernet Franc) and white wine grape pomace (Chardonnay) were prepared in 80% ethanol. An extract of red apple pomace was included as a comparison. The radical scavenging activities and phenolic profiles of the pomace extracts were determined through the measurement of oxygen radical absorbance capacity, DPPH radical scavenging activity, total phenolic content and flavonoids. The inhibitory effects of the pomace extracts on yeast and rat intestinal α-glucosidases were determined. Male 6-week old C57BLKS/6NCr mice were treated with streptozocin to induce diabetes. The diabetic mice were then treated with vehicle or the grape pomace extract to determine whether the oral intake of the extract can suppress postprandial hyperglycemia through the inhibition of intestinal α-glucosidases.

Results

The red grape pomace extract contained significantly higher amounts of flavonoids and phenolic compounds and exerted stronger oxygen radical absorbance capacity than the red apple pomace extract. Both the grape pomace extracts but not the apple pomace extract exerted significant inhibition on intestinal α-glucosidases and the inhibition appears to be specific. In the animal study, the oral intake of the grape pomace extract (400 mg/kg body weight) significantly suppressed the postprandial hyperglycemia by 35% in streptozocin-induced diabetic mice following starch challenge.

Conclusion

This is the first report that the grape pomace extracts selectively and significantly inhibits intestinal α-glucosidase and suppresses postprandial hyperglycemia in diabetic mice. The antioxidant and anti-postprandial hyperglycemic activities demonstrated on the tested grape pomace extract therefore suggest a potential for utilizing grape pomace-derived bioactive compounds in management of diabetes.

     

葡萄籽提取物、维生素E和硒的联合抗氧化作用研究

目的 探讨和分析葡萄籽提取物、维生素E和硒合理配伍后的复合制剂对人体抗氧化能力的影响。 方法 根据受试者的纳入标准筛选114名自愿参与者作为受试者,按试验前受试者血液中的丙二醛（MDA）、超氧化物歧化酶（SOD）活力和谷胱甘肽过氧化物酶（GSH-Px）活力情况分层后随机分为试验组和对照组,试验组受试者按每日服用量服用葡萄籽提取物、维生素E、硒复合制剂,对照组受试者按同等剂量服用安慰剂,连续服用3个月后,检测和分析2组受试者血液中MDA含量、SOD活力和GSH-Px活力的变化情况。结果 本研究试验组和对照组各50人。2组受试者的年龄及性别构成差异均无统计学意义（均P>0.05）。试验结束后受试者精神状态、睡眠质量、饮食、大小便等均未发现明显异常,胸片、心电图、腹部B超检查结果也均未发现异常改变,均未出现不良反应。试验前2组受试者MDA含量、SOD活力和GSH-Px活力的差异均无统计学意义（均P>0.05）。试验后试验组MDA含量明显低于对照组,SOD活力和GSH-Px活力明显高于对照组（均P<0.05）。试验后试验组MDA含量下降率、SOD活力升高率和GSH-Px活力升高率明显高于对照组（均P<0.01）。结论 葡萄籽提取物、维生素E、硒合理配伍后的复合制剂能够明显降低受试者的MDA含量、提高受试者的SOD活力和GSH-Px活力,葡萄籽提取物、维生素E和硒合理配伍后联合使用能够有效提升人体的抗氧化能力。