丝瓜降血脂及抗氧化作用的实验研究

目的： 观察丝瓜（LC）多酚的抗氧化作用及丝瓜对实验性高脂血症小鼠的影响。方法: 利用丙酮提取丝瓜多酚类物质，用福林法测定其含量并观察丝瓜多酚粗提液抑制羟自由基生成的能力。用高脂饲料喂养昆明小鼠建立高脂血症模型，以血脂康作为阳性对照观察饲料中补充丝瓜冻干品喂养对小鼠血清胆固醇（TC）、甘油三酯（TG）、低密度脂蛋白（LDL-C）、超氧化物歧化酶（SOD）及肝组织中丙二醛（MDA）的影响。结果: （1）新鲜丝瓜多酚含量为0.3 g/kg±0.1 g/kg。（2）新鲜丝瓜多酚粗提液具有较强的抑制羟自由基生成的能力。(3)与高脂模型组比较，低剂量丝瓜组、高剂量丝瓜组小鼠体重增加趋势明显减轻。(4)低剂量丝瓜组TC（4.19±0.37）mmol/L和LDL-C（2.77±0.79）mmol/L、高剂量丝瓜组TC（3.56±0.55）mmol/L和LDL（2.34±0.41）mmol/L、血脂康阳性对照组TC（4.59±0.96）mmol/L和LDL-C（3.25±0.67）mmol/L均低于高脂模型组TC(7.20±0.87)mmol/L和LDL-C(4.92±0.52)mmol/L（P＜0.01），其中高剂量丝瓜组TC、LDL-C下降最为明显。(5)低剂量丝瓜组和高剂量丝瓜组小鼠血清SOD分别为（337.00±29.73） U/mL和(349.00±9.99)U/mL，均高于高脂模型组和空白对照组，其中高剂量丝瓜组SOD活性明显高于高脂模型组（P＜0.01）。结论: 丝瓜多酚具有较强的抗氧化作用，丝瓜能明显降低高脂血症小鼠的体重、肝指数及血脂水平。     

不同加工方法对苦荆茶中多酚类物质含量的影响

目的：检测不同的加工方法对苦荆茶(Ilex．sp)中多酚类物质含量的影响。方法：利用多酚类物质与酒石酸铁反应生成稳定的有色物质进行定量比色分析。结果：同样的鲜叶采用绿茶的加工方法，茶叶中多酚类物质的含量明显高于干燥箱内烤干叶。结论：用绿茶加工方法制作苦荆茶，可减少多酚类物质的聚合及氧化，提高茶叶的品质。     

大豆纤维中的多糖—─多肽复合物

利用１ｍｏｌ／ＬＮａＯＨ溶液从大豆细胞壁物质（膳食纤维）中提出ＲＦ５，经柱层析进一步分级成ＰＲＦ５－１和ＰＲＦ５－２两种纯组分，它们均是多糖—多酚—多肽复合物。由β（１→４）糖苷键连的木聚糖构成多糖部分的主链结构，主链分别通过Ｃ３和Ｃ２分支点连有Ａｒａ和ＧｌｃＡ作为测链，ＰＲＦ５－２组分中在Ｃ３位还连有［Ａｒａ（１→４）Ｇｌｃ（１→］侧链。多酚类物质鉴定出其中主要的５种，分别是水杨酸、阿魏酸、香豆酸、香草酸和２，５－二羟基苯甲酸等。多糖与多肽之间是通过多酚（主要是阿魏酸和香豆酸）活泼羟基团的共价作用联系在一起。ＲＦ５对面团的粉质与拉伸特性有明显的改良作用。     

Dual function of (--)-epigallocatechin gallate (EGCG) in healthy human lymphocytes

(-)-Epigallocatechin gallate (EGCG), a catechin polyphenol component, is the main ingredient of green tea extract. Recently, increasing attention has been given to its anti-oxidant effects. However, several studies reported the oxidative effects of EGCG, suggesting that EGCG had a dual function of anti-oxidant and pro-oxidant potentials. In this study, we examined the influences of EGCG on healthy human whole blood lymphocytes and purified blood lymphocytes using a single-cell gel electrophoresis (SCG) assay. The results showed that EGCG suppressed the DNA strand breakage in whole blood lymphocytes at concentrations from 10(-8) to 10(-5)M, while it induced DNA strand breakage at concentration of 10(-3)M. Furthermore, EGCG at concentrations of 10(-6)-10(-4)M suppressed the DNA strand breakage induced by bleomycin (BLM) and H(2)O(2) in whole blood lymphocytes. In the same range of 10(-6)-10(-4)M, EGCG increased DNA strand breakage in purified blood lymphocytes, but suppressed the DNA breakage induced by BLM at lower concentrations from 10(-8) to10(-7)M. From these findings, we propose that EGCG might have a dual function of anti-oxidant and pro-oxidant in healthy human lymphocytes, which would involved in its inhibitory effects against DNA strand breakage induced by BLM and H(2)O(2).     

Evaluation of polyphenol bioavailability in rat small intestine

Summary Background Dietary polyphenols, which are contained in several foods of plant origin, have been reported to be effective protective agents against cardiovascular diseases and cancer. However, data on their absorption from the gastrointestinal tract are still scarce and, often, contradictory. Aim of the study In this report, evaluation of polyphenol bioavailability was carried out by using segments of the small intestine from rat. The extent of absorption throughout the small intestine of rat was evaluated with two model compounds, tannic acid and catechin, as representatives of high and low molecular weight polyphenols, respectively. The consequence of the binding of tannic acid to BSA on both tannic acid absorption and in vivo protein digestibility was also examined. Methods Polyphenol solutions of different concentrations were injected into the lumen of ligated segments (6 cm) of the small intestine and the segments incubated in buffer for 5 min. The residual amount of polyphenol in the lumen of each segment was assayed by maximum absorption in the UV/VIS optical spectrum as was the amount of compound that had crossed the gut wall into the incubation buffer. Digestibility of BSA and of a BSA-tannic acid complex was assayed with rats. Results The results indicated a significant, concentration-dependent, disappearance of both polyphenols from the small intestine of the rat, with higher uptake levels being evident for tannic acid (50 %) than catechin (30 %). However, complete transfer through the gut wall was not observed with tannic acid whilst low but significant amounts (10 %) were detected in incubation buffers with catechin. Partial binding of polyphenols by endogenous proteins in the intestinal lumen was also demonstrated. Complexing tannic acid with BSA (1:10 mol/mol) was not found to affect either the extent of interaction of tannic acid with the small intestine or the in vivo digestibility of the protein. Conclusions Our experiments show that tannic acid and catechin both interact with the gut but only catechin appears able to traverse the gut. In addition, they provide evidence for binding of tannic acid and catechin by endogenous proteins in the intestinal lumen. This may limit their absorption from the small intestine. BSA complexed with tannic acid was as readily digested as BSA alone. This may suggest that tannic acid exerts anti-nutritional effects by binding to proteins of the gut wall and interfering with gut function rather than by inhibition of dietary protein digestion. Received: 1 February 2001 / Accepted: 14 May 2001     

EFFECT OF MURINE RECOMBINANT IL-2 ON THE COURSE OF LUPUS-LIKE DISEASE IN (NZB×NZW) F1 Female Mice

ABSTRACT

The exacerbation of pre-existing autoimmune diseases is a potential toxic effect of immunoactive drugs. An increase in the incidence of autoimmune thyroiditis has been noted in patients treated with human recombinant interleukin-2 (rIL-2). In contrast, human rIL-2 tends to protect mice from autoimmunity. As the effects of murine rIL-2 on autoimmunity have not been reported in mice, lupus-prone female (NZB×NZW) F1 mice were treated with 20,000 IU murine rIL-2 intraperitoneally, twice weekly for 13 weeks, beginning at 15 weeks of age. No evidence of an exacerbating effect of murine IL-2 on the lupus disease of (NZB×NZW) F₁ mice was observed as no change in the following parameters were seen, namely mean survival time, mean body weight, anti-DNA and antinuclear antibody production. These results show that: 1) like human rIL-2, murine rIL-2 does not exacerbate autoimmunity in mice; 2) the biological effects of human as well as murine rIL-2 in mice differ from those seen with human rIL-2 in man. These latter findings suggest that the selection of the relevant animal species for immunotoxicity studies with recombinant cytokines and derivatives may be less straightforward than previously thought.     

Safety and adherence of Umezu polyphenols in the Japanese plum (Prunus mume) in a 12-week double-blind randomized placebo-controlled pilot trial to evaluate antihypertensive effects

Objectives

Medications or lifestyle changes to prevent or improve hypertension often press considerable efforts on patients suffering from mild hypertension. Capsules including Umezu polyphenols (UP), polyphenols in Japanese plums, may help them to control their blood pressure (BP). The aim of this study is to evaluate the effectiveness of UP on BP and its safety.

Methods

A total of 15 healthy workers without antihypertensive medication who had some concerns about their BP, preferably normal-high BP or hypertension level 1, were randomized in a double-blind manner into UP ingesting and placebo groups. Each subject was instructed to take four capsules daily for 12 weeks (daily UP dose, 800 mg for the UP ingesting group; and 0 mg for the placebo group). These subjects were followed for 12 weeks, and their BP both at home and at the examination site, as well as self-perceived quality-of-life outcomes and possible side effects, was monitored during that period. Group × time interactions on BP changes were examined.

Results

All of the 15 subjects completed the 12-week intervention trial. The BP changes did not significantly differ between the UP ingesting and placebo groups, neither at the examination site nor at home. But during the study period, no adverse effects were observed.

Conclusions

No remarkable effect of UP on BP was observed. However, a higher dose of UP was confirmed safe and high in adherence in this 12-week randomized controlled trial. Its effect on BP and other outcomes shall be confirmed in a larger sample.     

Polyphenolic content and antioxidant activity of some wild Saudi Arabian asteraceae plants

Objective:To study the antioxidant properties of crude extract of different Asteraceae plants.Methods:The antioxidant properties of six extracts were evaluated using different antioxidant tests,including free radical scavenging,reducing power,metal chelation,superoxide anion radical scavenging,total antioxidant capacity and inhibition of lipid peroxidation activities.Results:Picris cyanocarpa(P.cyanocarpa)and Anthemis deserti(A.deserti)had powerful antioxidant properties as radical scavenger,reducing agent and superoxide anion radical scavenger while Achillia fragrantissima(A.fragrantissima)and Artemissia monosperma(A.monosperma)were the most efficient as ion chelator(100%at 100,200 and 400μg/mL)A.fragrantissima and Rhanlarium appoposum(R.appoposum.)showed 100%inhibition on peroxidation of linoleic acid emulsion at 200 and 400μg/mL,while butylatedhydroxy toluene and ascorinc acid showed 100and 95%inhibition percentage at 400μg/mL,respectively.Those various antioxidant activities were compared to standard antioxidants such as butylated hydroxyl toluene and ascorbic acid.Conclusions:In most tests P.cyanocarpa and A.deserti had powerful antioxidant properties as radical scavenger,reducing agent and superoxide anion radical scavenger.     

Punicalagin promotes human villous trophoblast differentiation

Poor differentiation of trophoblasts is associated with placental dysfunction, predisposing women to multiple pregnancy disorders. Punicalagin, a prominent ellagitannin in pomegranate juice has been shown to exert anti-apoptosis and anti-oxidative effects in human trophoblasts. We hypothesized that punicalagin modulates trophoblast differentiation. We found that punicalagin-treated primary trophoblast showed reduced E-cadherin, higher Syncytin 1, more β−hCG, and increased GCM1, an upstream regulator of β−hCG. Punicalagin exposure of villous explants enhanced the number of cytotrophoblasts expressing the proliferation marker Ki67. We conclude that punicalagin enhances trophoblast differentiation and speculate that punicalagin might be used therapeutically in pregnancies at risk for placental dysfunction.