冬寒菜粉对正常小鼠免疫功能的影响

采用环磷酰胺造成兔疫抑制模型，观察本教研室自备的冬寒菜粉（MalvaCrispaPowder，MCP）对正常小鼠NK细胞活性、巨噬细胞吞噬功能和免疫器官重量的影响。结果表明：冬寒菜粉各剂量组NK细胞活性率显著高于对照组，而吞噬指数和吞噬百分率水平与对照组无差异；2．5％MCP组能提高脾脏重量。因此，冬寒菜粉可提高正常小鼠NK细胞活性，而对其无免疫抑制作用。     

膳食中斑蝥黄嘌呤的抗氧化作用

流行病学调查结果表明β-胡萝卜素等类胡萝卜素可预防癌症。体内实验亦证明斑蝥黄嘌呤能有效地清除单线态氧等自由基,防止自由基对细胞损伤,因而可作为一种抗癌因子。为进一步确定斑蝥黄嘌呤(简称CX)直接或间接的抗氧化作用,观察CX对渗出性素质疾患的影响(渗出性素质简称ED,为禽类V_E和Se缺乏引起严重水肿的一类疾患),作者选择来克亨鸡进行了动物实验。82只小鸡随机分为三组:P组、CX组及V_E组,动物数分别为36、36和10只。P组:饲以V_E及Se缺乏饲料,并补充相应的安慰剂作为对照(5g安慰剂/kg饲料);CX组;同样饲以缺乏V_E及Se但补充CX(5gCX/kg饲料)     

运用共振拉曼散射光谱法测定皮肤类胡萝卜素

[目的]用共振拉曼散射光谱法测试皮肤类胡萝卜素水平,观察机体类胡萝卜素变化情况。[方法]120名成年受试者按照其年龄、性别和试验前皮肤类胡萝卜素指数配对后,随机分为试验组和对照组。试验组人群每天补充β-胡萝卜素12.6mg,共8周。两组人群在试验前、试验第4周末和第8周末,分别运用共振拉曼散射光谱测试受试者皮肤类胡萝卜素,观察皮肤中类胡萝卜素水平变化情况。同时进行膳食调查,了解膳食摄入情况。[结果]试食组人群补充β-胡萝卜素第4周时皮肤类胡萝卜素指数比试验前的基础值上升了24.3%、第8周时比试验前的基础值上升了44.0%,且与对照人群相比差异有统计学意义(P<0.001)。[结论]由于两组人群在试验期间的膳食摄入情况没有差异,实验中试食组人群皮肤类胡萝卜素指数的增高可认为与补充β-胡萝卜素有关。共振拉曼散射光谱作为一种非创伤性的检测方法,可用于反映皮肤类胡萝卜素水平,进而提示机体类胡萝卜素的营养状况。     

沙姜中肉桂酸乙酯类化合物抗促癌作用的研究

采用EB病毒早期抗原 (EBV EA)诱导抑制实验、小鼠耳肿胀实验、表皮组织鸟氨酸脱羧酶活性 (ODC)实验及小鼠皮肤乳头状瘤诱导实验等方法对沙姜中肉桂酸乙酯类化合物进行抗促癌活性研究。结果显示 ,沙姜中的顺式 和反式 对甲氧基肉桂酸乙酯具有抗促癌活性 ,其IC5 0分别为 5 5和 9 5 μmol L。经进一步经典的小鼠皮肤乳头状瘤两阶段致癌实验、ODC实验及小鼠耳肿胀实验对该化合物的验证 ,该成分可有效地抑制由DMBA TPA诱导的小鼠皮肤乳头状瘤的生成 ,使荷瘤鼠比例及鼠荷瘤数降低 ,并可抑制小鼠皮肤ODC活性和小鼠的耳肿胀程度。提示沙姜中的对甲氧基肉桂酸乙酯具有抗促癌作用     

八种蔬菜粉脂溶性粗提物对人胃腺癌细胞增殖的影响

本实验以体外培养的人胃腺癌细胞株SGC－7901为材料，研究了八种蔬菜粉脂溶性粗提物（VPFE）对人胃癌细胞体外增殖的影响。VPEE的剂量（以培养液中卜胡萝卜素浓度计）为2×10~(－8)、2×10~(-7)、2×10~(-6)mol／L。结果：（1）生长曲线实验中，八种菜粉VPFE对胃癌细胞的增殖均有抑制作用。在VPFE高剂量组，各种菜粉的抑制作用均有显著性意义（P＜0.05），而中剂量组的作用在不同菜粉有一些差异；（2）集落形成实验中，冬寒菜、菠菜和紫油菜粉VPFE各剂量组均抑制了胃癌细胞的集落形成（P＜0．01），抑制作用呈剂量一反应关系。本次研究的结果为蔬菜防癌抗癌的实际运用积累资料。     

叶黄素对食管癌EC9706细胞增殖与分化的影响

叶黄素(lutein)是一种具有抗氧化作用的类胡萝卜素[1]。流行病学、体外试验和动物试验研究表明,给予叶黄素可以预防动脉粥样硬化,其抗氧化性能可以抵御游离基在人体内造成的细胞与器官损伤,并可防止因机体衰老引发的心血管硬化、冠心病和肿瘤[2]。补充叶黄素或提高叶黄素血液浓     

类胡萝卜素对人类健康的影响研究与展望

类胡萝卜素由于其具有强抗氧化性的生物活性而备受关注,大量研究显示类胡萝卜素在抗氧化、预防慢性病、抗癌、增强抵抗力等方面有重要作用,同时又作为维生素A前体,几乎无任何副作用,被广泛用于营养添加剂和功能性食品中,其中的叶黄素由于其独特的部位聚积受到广大研究者的青睐。目前很多研究仍处在动物实验阶段,为更好确证类胡萝卜素的生物学作用仍需进一步的临床干预试验。     

延缓衰老 促进健康

补充类胡萝卜素给身体健康保护 类胡萝卜素由植物合成,以色素形式存在于自然界,迄今为止已被发现了600多种,其中β-胡萝卜素、α-胡萝卜素、叶黄素和玉米黄质是目前研究比较深入、并被认为是比较重要的类胡萝卜素.     

类胡萝卜素抗癌作用的研究概述

流行病学调查,细胞学研究和动物实验结果均表明,类胡萝卜素是具有较强抗癌作用的一类天然化合物,它发挥其抗癌作用不需在体内转化为维生素 A(V_A),而是独立的。类胡萝卜素来源广泛,对人体无毒害作用。目前,人们还在不断深入地对其抗癌作用和作用机理进行研究。本文旨在对这方面的研究现状作一概述。     

“五菜”是天然的营养素补充剂

“菜”在《说文解字》中的解释为“草之可食者”,是可食用的草本植物的总称。“五菜”最早见于《黄帝内经》,历代注家多以葵、韭、藿、薤(音同谢)、葱五类蔬菜来解释五菜。其中,葵为五菜之首,又名冬寒菜、冬苋菜;韭就是大家常吃的韭菜;藿是指豆叶,即豆科植物的叶子;薤又名野蒜、薤白头;葱则是日常生活中吃到的葱。《黄帝内经》将这五类蔬菜分别与五味对应,葵甘、韭酸、藿咸、薤苦、葱辛。然而蔬菜种类繁多,远不是用“五菜”就能够概括的。     

Effects of excess vitamin A and canthaxanthin on salivary gland tumors

The effects of feeding semipurified diets supplemented with excess retinyl palmitate (20,000 and 100,000 IU/kg), β‐carotene (250 mg/kg), and canthaxanthin (250 mg/kg) on 7,12‐dimethylbenz[a]anthracene (DMBA)‐induced salivary gland tumors were studied in rats. None of the dietary supplements had a significant effect on tumor incidence. Tumor weights, however, tended to be lower in rats fed the dietary supplements compared with the controls. The incidence of tumor‐bearing rats with large tumors was significantly lower in rats fed canthaxanthin than in the control rats. At termination of the experiment, the levels of vitamin A were higher in plasma, liver, normal salivary glands, and the tumor of rats fed diets supplemented with the higher level of retinyl palmitate. Feeding the canthaxanthin‐supplemented diet had the opposite effect on tissue and plasma vitamin A levels. β‐Carotene supplementation was associated with higher vitamin A concentrations in the liver but not in plasma, salivary glands, or the tumor. The levels of β‐carotene were increased in tissues and plasma of rats fed the β‐carotene‐supplemented diet. The results suggest that in this experimental model, the diet‐induced modification of tissue or plasma vitamin A levels did not have an effect on tumor incidence.     

蔬菜类胡萝卜素与矿工肺癌队列研究

目的 :　了解食用蔬菜与云南锡业公司 (云锡 ,YTC)矿工肺癌危险性的关系。方法 :　在食物频率问卷 ( FFQ)重复性和有效性研究的基础上用 χ2 检验、单因素、多因素 Cox回归分析了 7965名 40岁以上云锡矿工肺癌高危人群不同蔬菜摄入量、总蔬菜摄入量和不同类胡萝卜素摄入量与其发生肺癌相对危险性的关系。结果 :　摄入不同水平蔬菜、类胡萝卜素的矿工 ,肺癌发病率不同 ;其中总蔬菜、根茎类、葱属蔬菜、芹菜、十字花科蔬菜、薯芋类、苦瓜等浅色瓜、豆芽菜、β-胡萝卜素、α-胡萝卜素、叶黄素和玉米黄质等在不同摄入水平时云锡矿工肺癌发病率有显著性差异( P<0 .0 5 ) ;总蔬菜、根茎类、葱属蔬菜、芹菜、十字花科蔬菜、薯芋类、苦瓜等浅色瓜、β-胡萝卜素、α-胡萝卜素与肺癌相对危险性呈负相关 ( RR<1 ,P<0 .0 5 ) ;经调整年龄、工龄、吸烟后 ,根茎类、芹菜、十字花科蔬菜、薯芋类、β-胡萝卜素、α-胡萝卜素仍显示与矿工肺癌危险性呈负相关 ( RR=0 .5～ 0 .75 ,P<0 .0 5 )。结论 :　蔬菜尤其是芹菜、根茎类、十字花科蔬菜、薯芋类、β-胡萝卜素、α-胡萝卜素对云锡矿工肺癌确有一定预防作用     

The effect of different levels of dietary ß‐carotene on DMBA‐induced salivary gland tumors

Different levels of ß‐carotene (0, 5, 25, 125, and 250 mg/kg diet) were tested for their chemoprevention effects using 9,10‐dimethyl‐1,2‐benzanthracene‐induced salivary gland tumor model in rats. Tumor incidence and tumor weights were slightly lower in rats fed diets supplemented with 25 mg or more ß‐carotene/kg diet. Hepatic vitamin A and ß‐carotene levels were increased in a dose‐dependent fashion, reaching a plateau at 125 mg ß‐carotene/kg diet. In plasma, ß‐carotene concentrations were also increased with an increase in dietary ß‐carotene. Vitamin A levels in plasma were not affected. The normal salivary glands had higher concentrations of ß‐carotene than did the tumors. The results suggest that the decreases in tumor incidence and tumor weight may be related to the increase in plasma and tissue levels of ß‐carotene as a result of feeding high levels of ß‐carotene.     

Lipoprotein carotenoid profiles and the susceptibility of low density lipoprotein to oxidative modification in healthy elderly volunteers

OBJECTIVES: To determine antioxidant levels in plasma, low density lipoprotein (LDL) and high density lipoprotein (HDL) before and after supplementation with a carotene mixture or lycopene; to examine the interrelationships between carotenoids and tocopherols in plasma, LDL and HDL under normal dietary conditions and after supplementation with carotene or lycopene; and to investigate whether supplementation with a carotene mixture or lycopene could enhance the ability of LDL to withstand oxidative stress in vitro, in a group of healthy elderly people aged > or =65 y. DESIGN: Randomized placebo controlled double blind study. SETTING: Free living urban adults in Ireland. Subjects: Fifty-one volunteers aged > or =65 y. INTERVENTIONS: Volunteers were each provided with capsules providing either 13.3 mg lycopene, or 11.9 mg carotene or placebo for 12 weeks. RESULTS: Both absolute and cholesterol standardized plasma carotenoid concentrations correlated strongly with LDL and HDL concentrations of carotenoids before and after supplementation with carotene or lycopene. Supplementation with a carotene mixture or lycopene had no effect on oxidative modification of LDL in vitro despite significant increases in plasma and LDL concentrations of lycopene, alpha-carotene and beta-carotene. CONCLUSIONS: The results of this study suggest that, in unsupplemented individuals, plasma can act as a biomarker of carotenoid and gamma-tocopherol concentrations in both LDL and HDL. Supplementation with carotenes or lycopene do not reduce or delay oxidation of LDL. These results support the assumption that carotenoids, such as beta-carotene and lycopene, may show protective effects because they are good markers of fruit and vegetable intake.     

Introductory remarks

The modifying effect of β‐carotene on benzo[a]pyrene (BP)‐induced tumors of the respiratory tract was investigated in Syrian hamsters. Groups of hamsters were fed a semisynthetic diet supplemented with either no or 56 mg/kg β‐carotene. Respiratory tract tumors were induced by intratracheal instillation of BP attached to ferric oxide. The β‐carotene and vitamin A contents of the liver were increased in the high β‐carotene group, but the serum β‐carotene levels were very low when compared with those commonly observed in humans. β‐Carotene supplementation did not affect the tumor response of the respiratory tract. Neither the incidence and severity of preneoplastic changes were influenced. However, there was a statistically significant inverse relationship between serum retinol content and the presence of respiratory tract tumors in survivors, regardless of the dietary treatment.     

硒强化沙棘果汁对大鼠红细胞膜脂质过氧化作用的影响

给正常成年大鼠喂饲添加沙棘果汁、硒强化沙棘果汁及维生素Ｃ（ＶＣ）的半纯化饲料，观察其对大鼠红细胞膜脂质过氧化作用的影响。结果表明，各实验组大鼠红细胞膜、血桨及肝脏脂质过氧化物（ＬＰＯ）含量显著低于正常对照组。红细胞膜硫基和唾液酸含量显著高于对照组，膜Ｎａ＋－Ｋ＋－ＡＴＰ酶活性也显著提高。提示：沙棘果汁能够显著降低大鼠红细胞膜的脂质过氧化反应，从而保护红细胞膜结构与功能的稳定。其中以硒强化沙棘果汁的作用更为显著。     

Phytoene, phytofluene, and lycopene from tomato powder differentially accumulate in tissues of male Fisher 344 rats

Tomato product consumption is inversely related to prostate cancer incidence, and lycopene (LYC) has been implicated in reduced prostate cancer risk. The contribution of other tomato carotenoids, phytoene (PE) and phytofluene (PF), toward prostate cancer risk has not been adequately studied. The relative uptake and tissue distribution of tomato carotenoids are not known. We hypothesize that PE and PF are bioavailable from a tomato powder diet or from a purified source and accumulate in androgen-sensitive tissues. In this study, 4-week-old male Fisher 344 rats (Harlan, Indianapolis, Ind) were prefed an AIN-93G powder diet composed of 10% tomato powder containing PE, PF, and LYC (0.015, 0.012, and 0.011 g/kg diet, respectively). After 30-day tomato powder feeding, hepatic PF concentrations (168 ± 20 nmol/g) were higher than PE or LYC (104 ± 13 and 104 ± 13 nmol/g, respectively). In contrast, LYC, followed by PF, had the highest accumulation of the measured carotenoids in the prostate lobes and seminal vesicles. When tomato powder–fed rats received a single oral dose of either approximately 2.7 mg PE or approximately 2.7 mg PF, an increase in the dosed carotenoid concentration was observed in all measured tissues, except in the adrenal. The percentages of increases of PF were greater than that of PE in liver, serum, and adipose (37%, 287%, and 49% vs 16%, 179%, and 23%, respectively). Results indicate that the relative tomato-carotenoid biodistribution differs in liver and androgen-sensitive tissues, suggesting that minor changes in the number of sequential double bonds in carotenoid structures alter absorption and/or metabolism of tomato carotenoids.     

Plasma and lung macrophage responsiveness to carotenoid supplementation and ozone exposure in humans

OBJECTIVE: To examine the effect of ozone exposure and vegetable juice supplementation on plasma and lung macrophage concentrations of carotenoids. DESIGN: A randomized trial. SETTING: Subjects were exposed to ambient air prior to antioxidant supplementation and to ozone after antioxidant supplementation or placebo. Exposures occurred while exercising intermittently in a controlled metabolic chamber at the Human Studies Division, US EPA. SUBJECTS: In all, 23 healthy subjects between ages of 18 and 35 y. INTERVENTIONS: Subjects consumed a low fruit and vegetable diet for 3 weeks. After the first week, subjects underwent a sham exposure to filtered air with exercise, followed by bronchoalveolar lavage (BAL). Subjects were randomly assigned into supplement (one can vegetable juice, vitamins C and E daily) or placebo (orange soda, placebo pill daily) groups for 2 weeks. After the 2-week intervention, subjects were exposed to 0.4 ppm (784 microg/m(3)) ozone for 2 h with exercise followed by BAL. Blood samples were drawn before, immediately after and 3 h postexposure on each exposure day. The concentrations of nine carotenoids were determined by HPLC in BAL macrophages and plasma samples. RESULTS: Plasma concentrations of all the carotenoids that were present in the vegetable juice (except cis-beta-carotene) increased significantly in the supplemented group. Lung macrophage alpha-carotene concentrations increased significantly, lycopene isomers increased slightly, and all other carotenoids decreased (nonsignificantly) in the supplementation group following the intervention. Ozone exposure resulted in decreases in several carotenoids in plasma of the placebo group, but not in the supplemented group. CONCLUSIONS: Lung macrophage concentrations of carotenoids can be manipulated by diet. Ozone is a potent environmental oxidant that appears to reduce plasma carotenoids in nonsupplemented individuals.     

The effects of vitamin A, beta-carotene and canthaxanthin on vitamin A metabolism and immune responses in the chick

Chicks were fed diets containing, 0, 0.85 and 350 mg/kg vitamin A and 1 g/kg beta-carotene or canthaxanthin from hatching. Carotene increased and canthaxanthin depressed plasma and hepatic vitamin A concentrations. High vitamin A levels decreased the concentration of both carotenoids. Neither carotene nor canthaxanthin affected intestinal carotene cleavage in vitro. T-lymphocyte proliferative responses were decreased at low vitamin A intakes and enhanced at the high vitamin A intake. Carotene and canthaxanthin fed with 0.85 mg/kg vitamin A had no effect on immune response and with 350 mg/kg vitamin A prevented the enhancement of the proliferative response. It is concluded that immune response in the chick is modulated by vitamin A; carotene and canthaxanthin effects are probably due to influences on vitamin A metabolism.     

Effect of excess iron intake on liver folate repletion in rats

Folic acid deficiency was induced in rats by feeding folate deficient diet containing normal (35 mg iron/kg diet) or marginal amounts (20 mg iron/kg diet) of iron. The effect of excess iron intake on liver folate repletion following supplementation with folic acid was studied. Large quantities of iron supplements (210 mg iron/kg diet) had no adverse effect on liver folate repletion. On the other hand the replenishment of liver folate reserves was better with excess iron intake.