Molecular mechanisms for anti-aging by natural dietary compounds

Aging is defined as a normal decline in survival with advancing age; however, the recent researches have showed that physiological functions of the body change during the aging process. Majority of the changes are often subject to a higher risk of developing diseases, such as cardiovascular disease, type II diabetes, Alzheimer's disease, Parkinson's disease, as well as the dysregulated immune and inflammatory disorders. Aging process is controlled by a complicated and precise signaling network that involved in energy homeostasis, cellular metabolism and stress resistance. Over the past few decades, research in natural dietary compounds by various organism and animal models provides a new strategy for anti-aging. Natural dietary compounds act through a variety mechanisms to extend lifespan and prevent age-related diseases. This review summarizes the current understanding on signaling pathways of aging and knowledge and underlying mechanism of natural dietary compounds that provide potential application on anti-aging and improve heath in human.     

有机锗(Ge-132)慢性毒理试验

为了解有机锗Ｇｅ－１３２的慢性毒理作用，以Ｇｅ－１３２２，１０，５０ｍｇ／ｋｇＢＷ的剂量喂养雌雄大鼠２年，观测体重、血细胞、生化、病理等指标。结果表明，对照组与实验组间各项指标均无明显的差别，推荐ＡＤＩ至少为０．５ｍｇ／ｋｇ。     

Bacillus cereus, the causative agent of an emetic type of food-borne illness

Bacillus cereus is the causative agent of two distinct forms of gastroenteritic disease connected to food-poisoning. It produces one emesis-causing toxin and three enterotoxins that elicit diarrhea. Due to changing lifestyles and eating habits, B. cereus is responsible for an increasing number of food-borne diseases in the industrial world. In the past, most studies concentrated on the diarrhoeal type of food-borne disease, while less attention has been given to the emetic type of the disease. The toxins involved in the diarrhoeal syndrome are well-known and detection methods are commercially available, whereas diagnostic methods for the emetic type of disease have been limited. Only recently, progress has been made in developing identification methods for emetic B. cereus and its corresponding toxin. We will summarize the data available for the emetic type of the disease and discuss some new insights in emetic strain characteristics, diagnosis, and toxin synthesis.     

Toxicological issues associated with production and processing of meat

Meat is a very complex and continuously changing ex vivo system of various high- and low-molecular substances that can be used for satisfying needs of the human organism for metabolic energy, building material and fulfilling of the other vital functions. A great majority of these substances are useful and safe for the consumer. Yet, meat and meat products may always contain substances exerting detrimental effects to the consumer's organism. The present paper is a literature review of the most important potentially toxic substances found in meat and meat products; their classification, ways of getting into the meat or formation during meat processing, undesirable physiological outcomes and biochemical mechanisms of their toxic effects, and methods for reduction of these responses.     

Resveratrol bioavailability and toxicity in humans

Numerous data are now available on the beneficial properties of the polyphenolic compound resveratrol including its anti‐inflammatory and antitumor effects. However, few studies have been performed with resveratrol in humans, and the results of these studies appear fragmentary and sometimes contradictory due to variations in conditions of administration, protocols and methods of assessment. This review article presents the results of recent studies investigating the pharmacokinetics, bioavailability, and toxicity of resveratrol in humans. Resveratrol is well absorbed, rapidly metabolized, mainly into sulfo and glucuronides conjugates which are eliminated in urine. Resveratrol seems to be well tolerated and no marked toxicity was reported. These data are important in the context of human efficacy studies, and they provide further support for the use of resveratrol as a pharmacological drug in human medicine.     

芦荟汁液浓缩干品(90 d)亚慢性毒性研究

为观察芦荟汁液浓缩干品的亚慢性毒性,选用健康断乳SD大鼠96只,随机分为4组,每组24只,雌雄各半,分别灌喂给予芦荟汁液浓缩干品0、1.65、3.3、6.6 g/kg BW,连续90 d.结果表明,芦荟汁液浓缩干品使大鼠排便量增加,粪便松软;雄性3个剂量组大鼠体重增长明显缓慢(P<0.05)、食物利用率降低(P<0.01),雌性体重无明显影响,3.3、6.6 g/kg BW剂量组食物利用率下降(P<0.05);血液学指标,肝、肾功能,血糖、血脂等生化指标无明显影响;尿NAG、ALP酶活性显著升高(P<0.01).病理检查,芦荟汁液浓缩干品引起肾小管上皮、肠系膜淋巴结、结肠粘膜固有层色素沉积,肾通透性增强.6.6 g/kg BW剂量组出现1例肾母细胞瘤,1.65 g/kg BW剂量组出现1例肾非典型增生,肝、脾、睾丸(或卵巢)等脏器未见有意义的病理损伤.本实验条件下,芦荟汁液浓缩干品有作用剂量为1.65 g/kg BW(芦荟甙330 mg/kg BW).     

Two food-borne heterocyclic amines: metabolism and DNA adduct formation of amino-alpha-carbolines

The amino-alpha-carbolines 2-amino-9H-pyrido[2,3-b]indole (AalphaC) and 2-amino-3-methyl-9H-pyrido-[2,3-b]indole (MeAalphaC) are two mutagenic and carcinogenic heterocyclic amines formed during ordinary cooking. Amino-alpha-carbolines can be formed in model systems by pyrolyzing tryptophan or proteins of animal or vegetable origin, furthermore they are found in many cooked foods, such as fish, meat, and chicken. The specific mutagenicity of the amino-alpha-carbolines are lower in the Ames Salmonella assay than other heterocyclic amines, but in rodent studies the carcinogenicity of the amino-alpha-carbolines are comparable to other heterocyclic amines. The metabolic pathways of the amino-alpha-carbolines have been studied in vitro and in vivo, and the detoxified phase I and phase II metabolites characterized and quantified. The metabolic activation of the amino-alpha-carbolines and the formation of DNA-adducts have also been studied. Characteristic for the amino-alpha-carbolines are that relatively large amounts of these compounds in rat and human hepatic microsomes are activated to potent carcinogenic compounds compared with other heterocyclic amines, but further in vivo studies of the amino-alpha-carbolines are needed to highlight these indications. In this review, the main characteristics with focus on the metabolism and the DNA-adduct formation of the amino-alpha-carbolines are described and compared with other heterocyclic amines.     

硒对铅毒性拮抗作用的研究进展

铅是环境中重要的重金属污染物,对人体的各个系统均能产生毒性和损伤。硒是人体必需的微量元素之一,大量研究表明,硒与铅存在着相互拮抗作用。硒和铅在动物或人体内的含量呈负相关,硒不仅能够拮抗铅的吸收和蓄积,促进铅的排泄,还能拮抗铅导致的机体各组织和细胞的氧化应激和免疫损伤、神经系统毒性、听力损伤、遗传和生殖毒性、肝肾毒性、DNA损伤等毒性作用。本文从上述几方面综述了近年来硒对铅毒性拮抗作用的研究进展。硒在人体内发挥生理作用主要通过硒蛋白实现,本文还阐述了硒拮抗铅毒性的作用与硒蛋白的关系方面的研究进展。尽管如此,硒拮抗铅毒性作用的研究机制仍然不明确。此外,硒对人体的营养必需剂量和毒性剂量之间的范围非常窄,因此,研究硒对人体健康的保护作用的剂量效应关系是实施科学补硒的前提和基础。     

降低卷烟TPM含量及其毒性的技术研究：Ⅰ.卷烟TPM减毒剂的初步筛选

本文对降低卷烟ＴＰＭ含量及其毒性的技术进行了研究。试验采用正交试验设计，通过对卷烟配方进行改造，ＴＰＭ含量测定，鼠伤寒沙门氏菌营养缺陷型恢复突变试验（Ａｍｅｓ试验），小鼠脊髓微核实验，评吸鉴定等方法，筛选鉴定出了２个较好的配方组合，结果表明：（１）２个配方组合均能显著降低卷烟ＴＰＭ含量及其毒性。（２）应用该技术改造卷烟配方，对原配方无不良影响。     

Molecular basis of cadmium toxicity

Cadmium has been shown to manifest its toxicity in human and animals by mainly accumulating in almost all of the organs and kidney is the main target organ where it is concentrated mainly in cortex. Environmental exposure of cadmium occurs via food, occupational industries, terrestrial and aquatic ecosystem. At molecular level, cadmium interferes with the utilization of essential metals e.g. Ca, Zn, Se, Cr and Fe and deficiencies of these essential metals including protein and vitamins, exaggerate cadmium toxicity, due to its increased absorption through the gut and greater retention in different organs as metallothionein (Cd-Mt). Cadmium transport, across the intestinal and renal brush border membrane vesicles, is carrier mediated and it competes with zinc and calcium. It has been postulated that cadmium shares the same transport system. Cadmium inhibits protein synthesis, carbohydrate metabolism and drug metabolizing enzymes in liver of animals. Chronic environmental exposure of cadmium produces hypertension in experimental animals. Functional changes accompanying cadmium nephropathy include low molecular weight proteinuria which is of tubular origin associated with excess excretion of proteins such as beta 2 microglobulin, metallothionein and high molecular weight proteinuria of glomerular origin (excretion of proteins such as albumin IgG, transferrin etc.). Recent data has shown that metallothionein is more nephrotoxic to animals. Cadmium is also toxic to central nervous system. It causes an alterations of cellular functions in lungs. Cadmium affects both humoral and cell mediated immune response in animals. Cadmium induces metallothionein in liver and kidney but under certain nutritional deficiencies like protein-calorie malnutrition and calcium deficiency, enhanced induction and greater accumulation of cadmium metallothionein has been observed.     

Effect of cholestin on toxicity of vitamin A in rats

A study was undertaken to investigate the effect of cholestin on the toxicity of vitamin A in male wistar rats. The rats were divided into six groups and fed different diets with or without supplement of 1% cholestin and 25,000-50,000 (IU) vitamin A for 2 months. Hence, the symptoms of vitamin A toxicity in rats included loss of body weight, hepatotoxicity and nephrotoxicity. However, these toxic effects of vitamin A were significantly reduced when the rats fed a diet supplemented with cholestin. Furthermore, the level of vitamin A in the serum of rats treated with cholestin and vitamin A was higher than that of the rats treated with vitamin A alone. It indicated that cholestin might play a role in reducing the toxic effect of vitamin A in rats.     

Effect of taurine on toxicity of vitamin A in rats

A study was undertaken to investigate the effect of taurine on the toxicity of vitamin A in male wistar rats. The rats were divided into six groups and fed different diets with or without supplements of 5% taurine and 25,000–50,000 (IU) vitamin A for 2 months. It was found that the body weight of rats, the ratios of liver and kidney weight to body weight, and the level of glutathione in the liver were decreased with increasing the dose of vitamin A. The levels of vitamin A in the liver and kidney, the levels of thiobarbituric acid-reactive substances (TBARS) in the plasma and liver, the activities of aspartate transaminase (AST) and alanine transaminase (ALT) in the plasma, and the levels of blood urea nitrogen (BUN) and creatinine in the plasma of rats were increased with the increasing dose of vitamin A. Hence, symptoms of vitamin A toxicity in rats included loss of body weight, hepatotoxicity and nephrotoxicity. However, these toxic effects of vitamin A were significantly reduced when the rats were fed the diet with the supplement of taurine. Furthermore, the level of vitamin A in the serum of rats treated with taurine and vitamin A was higher than that of rats treated with vitamin A alone. This indicated that taurine might play a role in reducing the toxic effect of vitamin A in rats.     

磺酰脲类除草剂毒性及多残留检测技术研究进展

磺酰脲类除草剂是一种高效、广谱、高选择性的除草剂,主要用于防除阔叶杂草和禾本科杂草。磺酰脲类除草剂在现代农业生产中发挥了重要作用,但其农药残留问题也给生态环境和农产品质量安全造成诸多负面影响。本文主要对磺酰脲类除草剂的毒性危害、限量标准、残留检测的前处理以及仪器分析方法进行综述。目前对于磺酰脲类除草剂残留的检测主要涉及到土壤和水,其次还有粮谷、动物源性食品等多种基质,国内对于此类除草剂残留检测常用的前处理方法为固相萃取法,C_(18)为常见填料,在仪器分析方面,液相色谱-质谱联用法以其灵敏度高、能检测痕量水平的残留而成为此类除草剂分析的首选方法。同时,国内外针对此类除草剂的残留检测,已经由过去的单残留检测向多残留检测发展。     

抗糖尿病功能因子及其作用机理研究进展

就近年来国内外有关天然资源防治糖尿病的功能因子及其降糖作用的机理进行了概述,并指出研发功能食品在预防糖尿病的发生及延缓并发症的发展方面有着广阔的应用前景。     

决明子乙醇提取物的亚慢性毒性研究

为观察决明子乙醇提取物的亚慢性毒性 ,选用健康断乳Wistar大鼠 12 0只 ,随机分为 6组(1个阴性对照组和 5个剂量组 ) ,每组 2 0只 ,雌雄各半 ,分别以 5、15、2 5、35、4 5g生药量 kgBW 剂量掺入饲料 ,喂养大鼠 90d。结果表明 ,决明子乙醇提取物各剂量组均使大鼠肾 体比、肝 体比比值升高 ,肾、结肠、直肠、肠系膜淋巴结色素沉积 ,肠系膜淋巴结反应性增生。 15 0g kgBW 及以上剂量组脾 体比、白细胞计数升高 ,结肠浅表性粘膜炎。 2 5 0g kgBW 及以上剂量组动物体重增长缓慢 ,食物利用率下降 ,睾丸萎缩。作用靶器官 :肾、结肠、直肠、肠系膜淋巴结、睾丸。本实验条件下 ,决明子乙醇提取物最小毒副作用剂量为 5 0g kgBW,按 10 0倍安全系数计算 ,折合人体日摄入量为 3g ,小于药典规定的日最小摄入 9g的限量要求。本研究表明决明子作为保健食品原料长期大量摄入存在一定安全隐患 ,应限制使用剂量和服用期限 ,不宜列入“既是食品又是药品的物品名单”。     

Reproductive and neurobehavioural toxicity study of chlorpropham in mice

Chlorpropham was given in the diet to provide levels of 0 (control), 500, 1,000, and 2,000mg/kg from 5 weeks of age of the F0 generation to 9 weeks of age of the F1 generation in mice, and selected reproductive and neurobehavioural parameters were measured. There were no adverse effects of chlorpropham on either litter size or litter weight and sex ratio at birth. The average body weight of offspring was significantly reduced in the middle-dose group at postnataldays (PNDs) 0 and 4 in female offspring, and was significantly increased in the middle-dose group at PND 14 in male offspring. In neurobehavioural parameters, surface righting at PND 4 was significantly affected in a dose-related manner, and negative geotaxis at PND 4 was significantly accelerated in a dose-related manner in female offspring. In male offspring, surface righting at PND 7 was significantly depressed in the middle-dose group, and olfactory orientation at PND 14 was significantly affected in the low- and middle-dose groups. The dose levels of chlorpropham in the present study produced few adverse effects in reproductive and neurobehavioural parameters in mice.     

Roles of stress response-related signaling and its contribution to the toxicity of zearalenone in mammals

Zearalenone (ZEA) is a mycotoxin frequently found in cereal crops and cereal-derived foodstuffs worldwide. It affects plant productivity, and is also a serious hazard to humans and animals if being exposed to food/feed contaminated by ZEA. Studies over the last decade have shown that the toxicity of ZEA in animals is mainly mediated by the various stress responses, such as endoplasmic reticulum (ER) stress, oxidative stress, and others. Accumulating evidence shows that oxidative stress and ER stress signaling are actively implicated in and contributes to the pathophysiology of various diseases. Biochemically, the deleterious effects of ZEA are associated with apoptosis, DNA damage, and lipid peroxidation by regulating the expression of genes implicated in these biological processes. Despite these findings, the underlying mechanisms responsible for these alterations remain unclear. This review summarized the characteristics, metabolism, toxicity and the deleterious effects of ZEA exposure in various tissues of animals. Stress response signaling implicated in the toxicity as well as potential therapeutic options with the ability to reduce the deleterious effects of ZEA in animals were highlighted and discussed.     

植酸对腐败希瓦氏菌的抑菌机理

结合植酸对南美白对虾的保鲜,以虾体优势腐败菌-腐败希瓦氏菌为研究对象,利用植酸溶液处理后,通过对细菌的抑菌效果及最小抑菌浓度、细菌生长曲线、碱性磷酸酶（AKP）等的测定研究其抑菌机理。结果表明,植酸对腐败希瓦氏菌有较强的抑菌效果,最低抑菌浓度（体积分数）为0.2%。同对照组相比,植酸能够影响细菌的生长规律,使细胞破损。细胞壁和细胞膜遭到破坏,AKP及电导率均增大,初步阐述了植酸对腐败希瓦氏菌的抑菌机理。