The subacute toxicity of glucosylthiazolidine-4-carbonic acid in rats

Glucosylthiazolidine-4-carbonic acid, an intermediate of the Maillard reaction between D-glucose and L-cysteine, was given in doses of 0, 25, 50 or 100 mg/kg b.w. by oral intubation to male and female rats for 21 days. General appearance, growth, food consumption, haematology, urine analysis and serum chemistry including determinations of enzyme activities, organ weights and macroscopic and microscopic pathology were used as criteria for adverse effects. Effects on the kidneys were indicated by oliguria and decreased specific gravity of the urine in males and histopathological changes of the proximal tubules in females. The no-effect dose established from this study is 25 mg/kg b.w.     

Modulation of doxorubicin-induced genotoxicity by squalene in Balb/c mice

The present study aims to evaluate the protective effect of squalene against the genotoxicity of the chemotherapeutic agent doxorubicin (Dox) using two genotoxicity assays, the micronucleus assay and the comet assay. Different groups of mice were fed squalene at the doses of 1 and 4 mmol g(-1) body weight (100 or 400 μl as squalene oil) either at 4 h before or 1 h after Dox (20 mg kg(-1)) treatment. 24 h after the Dox treatment, bone marrow erythrocytes were evaluated for the incidence of micronuclei, and the induced DNA strand breaks were examined in heart tissue by the alkaline comet assay. As expected, Dox significantly induced micronuclei in polychromatic (immature) erythrocytes, as well as in total erythrocytes. The frequency of Dox-induced micronucleated erythrocytes was significantly reduced in the mice treated with squalene both before and after Dox administration. Squalene itself obviously did not induce any micronuclei in bone marrow erythrocytes. The comet assay also demonstrated a significant increase in DNA damage, especially DNA single strand breaks in the Dox-treated group of mice as compared to the control. The Dox-induced DNA damage was also effectively reduced by squalene when it was administered either before or after the Dox treatment. Squalene did not induce any significant DNA damage by itself. Compared to the pre-treatment of squalene, post treatment gave rise to more effective prevention against Dox-induced DNA damage. The data suggest that the complimentary use of squalene with Dox will be beneficial to reduce the adverse effect of Dox in cancer chemotherapy, such as the increased incidence of undesirable mutagenic side effects.     

Functional and proliferative effects of repeated low‐dose oral administration of furan in rat liver

Scope: Furan, a food contaminant formed during heat processing, induces hepatocellular tumors in rodents and high incidences of cholangiocarcinomas in rats even at the lowest dose (2 mg/kg b.w.) administered. Initial estimates suggested that human intake of furan may be as high as 3.5 μg/kg b.w./day, indicating a relatively narrow margin of exposure. The aim of this study was to establish dose–response data for cytotoxicity, regenerative cell proliferation and secondary oxidative DNA damage in livers of male F344 rats treated with furan at doses ≤2 mg/kg b.w. for 28 days. Methods and results: No significant signs of hepatotoxicity other than a mild, dose‐dependent increase in serum cholesterol and unconjugated bile acids, and no evidence of oxidative DNA damage were seen. Histopathological alterations and proliferative changes were restricted to subcapsular areas of the left and caudate liver lobes. Conclusion: Although statistically significant effects were only seen at the 2 mg/kg b.w. dose during the course of our study, a ～two and ～threefold increase in 5‐bromo‐2′‐deoxyuridine labeling index was observed at 0.1 and 0.5 mg/kg b.w., respectively, suggesting that chronic exposure to doses even below 2 mg/kg b.w. may cause proliferative changes in rat liver and highlighting the need to assess furan carcinogenicity at lower doses.     

A safety study of oral xanthohumol administration and its influence on fertility in Sprague Dawley rats

Xanthohumol (XN) is a prenylated chalcone, which has been shown to possess a broad range of potential cancer preventive and additional biological activities. In the present study, we have determined the subchronic 4-wk toxicity of XN and monitored its influence on fertility and development of offspring in two fertility studies. Four-week-old female Sprague Dawley (SD) rats were treated with 0.5% XN in the diet or with 1,000 mg XN/kg body weight (b.w.) per day by gavage for 28 days. No remarkable treatment-related changes in general appearance and b.w. occurred during the study. After autopsy, liver, kidney, lung, heart, stomach, and spleen were examined macroscopically and histopathologically. Relative liver weights of animals in both treatment groups were significantly reduced by 30--40% in comparison with the control group, indicating weak hepatotoxicity. Also, mammary glands of treated rats appeared less developed compared to the controls. Consequently, we investigated the influence of XN on rat reproduction. In two fertility studies, XN (100 mg/kg b.w. per day), given either for 4 wk prior to or during mating, gestation, and nursing, did not cause any adverse effects on female reproduction and the development of offspring. Noteworthy, treatment of male rats prior to mating significantly (p=0.027) increased the sex ratio of male to female offspring. Overall, lifelong treatment at a daily dose of 100 mg/kg b.w. in a two-generation study did not affect the development of SD rats.     

番茄红素的安全性评价及对小鼠免疫功能的影响

目的：研究番茄红素的食品安全性及对小鼠免疫功能的影响。方法：进行大鼠30 d喂养实验,小鼠急性毒性实验,测定小鼠细胞免疫功能、体液免疫功能、单核-巨噬细胞功能及NK细胞活性。结果：雌、雄小鼠的番茄红素急性经口毒性＞2 666.64 mg/kg,属实际无毒级;番茄红素200、433.33、666.67 mg/（kg•d）剂量（以体质量计,下同）在30 d喂养实验中没有对大鼠的血液常规和血清生化指标产生影响,且Ames实验、小鼠骨髓细胞微核实验、小鼠精子畸形实验结果呈阴性;以33.33、66.67、200 mg/（kg•d）3 个剂量进行小鼠免疫功能实验,200 mg/（kg•d）剂量组的鸡红细胞吞噬指数、自然杀伤（natural killer,NK）细胞活性高于阴性对照组,且差异均有统计学意义（P＜0.05）。结论：番茄红素食品安全性良好,高剂量番茄红素作为食品添加剂在小型啮齿类动物实验中具有增强免疫力的功能。     

Effect of black pepper and piperine on bile secretion and composition in rats

The influence of black pepper (Piper nigrum L.) and its active principle, piperine on the secretion and composition of bile was investigated in the rat. They were administered by gavage (black pepper at 250 or 500 mg and piperine at 12.5 or 25 mg/kg body wt.) or fed in the diet for 4 weeks (black pepper at 0.2 and 0.4%, piperine at 0.01 and 0.02%). The lower dose by gavage of black pepper caused an increase in bile solids while with other treatments bile secretion or dry matter in bile was not changed. Dietary feeding of black pepper caused an increase in bile flow with a concomitant decrease in bile solids -- a hydrocholagoguic effect. Cholesterol and bile acid output were not affected by black pepper or piperine at either level irrespective of the mode of administration; in contrast, the secretion of uronic acids in bile was enhanced by both levels of pepper as also of piperine indicating possible excretion of some of the components of black pepper or of piperine as glucuronides.     

Intermittent administration of brain-derived neurotrophic factor (BDNF) ameliorates glucose metabolism and prevents pancreatic exhaustion in diabetic mice

We previously demonstrated that repetitive administration of brain-derived neurotrophic factor (BDNF) ameliorates glucose metabolism and energy expenditure in obese diabetic db/db mice. However, we have not evaluated in detail the effect of single or intermittent BDNF administration on glucose metabolism in a diabetic animal model. The objectives of this study were to examine the dose-response effect and dosing interval of BDNF administration in db/db mice and to evaluate the effect of intermittent BDNF administration on pancreatic function in db/db mice. We evaluated the dose-response effect of BDNF by single administration in db/db mice. First, single administration of BDNF greater than 70 mg/kg significantly reduced blood glucose concentration one day after administered, and the BDNF effect was maintained for 6 d. Next, the effects of BDNF administered twice a week at 4, 10, 25, and 62.5 mg/kg on blood glucose concentration, and the effects of BDNF administered once a week at 10, 20, 30, 50, and 70 mg/kg on blood glucose concentration were examined in db/db mice. In the intermittent treatment studies, BDNF dose-dependently ameliorated glucose metabolism by not only the twice-a-week administration but also the once-a-week administration. Lastly, because BDNF reduces the food intake of obese hyperphagic diabetic mice, the effects of BDNF administered once or twice a week on the blood glucose concentration and plasma and pancreatic insulin concentrations in db/db mice were compared with those of the vehicle under pair-fed conditions. Under pair-fed conditions, the intermittent administration of BDNF (25 mg/kg, twice a week, or 50 mg/kg, once a week) significantly reduced the blood glucose concentration and increased the plasma and pancreatic insulin concentrations compared with those in the pair-fed vehicle-treated db/db mice. This indicates that the prolonged hypoglycemic effect of BDNF is not simply due to the reduction of food intake. In conclusion, we demonstrated that the intermittent administration of BDNF ameliorates glucose metabolism and prevents pancreatic exhaustion in obese diabetic mice. These findings indicate that BDNF may have potential as a unique hypoglycemic agent for the treatment of diabetes at a fundamental level with good patient compliance.     

Antioxidant effects of flavonoids used as food additives (purple corn color, enzymatically modified isoquercitrin, and isoquercitrin) on liver carcinogenesis in a rat medium-term bioassay

To clarify the effects of purple corn color, enzymatically modified isoquercitrin (EMIQ), and isoquercitrin (IQ), registered as natural food additives in Japan, on liver carcinogenesis in vivo, a medium-term bioassay was employed. A total of 100 male F344 rats were divided into 5 groups; groups 1 to 4 were given a single intraperitoneal injection of diethylnitrosamine (200 mg/kg b.w.) on day 1. From weeks 2 to 8, they were administered basal diet purple corn color, EMIQ, or IQ as containing test chemicals at doses of 1.0% (groups 1 and 5), 0.1% (group 2), 0.01% (group 3), or 0% (group 4) (experiments 1, 4, and 5). All rats were subjected to two-thirds partial hepatectomy at week 3 and were sacrificed at week 8. Purple corn color exerted no significant modifying effects on GST-P positive foci, preneoplastic foci, development in the liver. However, serum of rats treated with purple corn color provided evidence of antioxidant power significantly by potential antioxidant (PAO) test in vivo (experiment 2). And microarray analyses showed purple corn color to induce RNA expression such as P450 (cytochrome) oxidoreductase, phosphatidylinositol 3-kinase, and phospholipase A2 (experiment 3). Higher doses of EMIQ or IQ with strong antioxidant power in vivo by PAO test treated groups were correlated with smaller numbers of GST-P positive foci, with Spearman's rank correlation coefficients of P= 0.002 and P= 0.049, respectively (experiments 4 and 5). Therefore, the tested food additives may be effective as antioxidants in vivo and have chemopreventive potential against liver preneoplastic lesion development.     

LACK OF ADVERSE INFLUENCE OF BLACK PEPPER, ITS OLEORESIN AND PIPERINE IN THE WEANLING RAT

Black pepper, its oleoresin or its active principle piperine fed to rats at doses 5 to 20 times normal human intake did not cause any adverse effect on: (1) growth, food efficiency ratio and organ weights; (2) RBC, WBC and differential counts; (3) the levels of blood constituents like hemoglobin, total serum proteins, albumin, globulin, sugar and cholesterol; (4) the levels of serum aminotransferases and phosphatases and (5) fat and nitrogen balance.     

Antimutagenic activity of lettuce and chard extracts

The ability of lettuce and chard extracts to reduce the mutagenic activity of Benzo[a]pyrene was studied. In this experiment several groups of male Balb/C mice were treated with different doses of the substances under study. B[a]p was administered at doses of 36 and 72 mg/kg of body weight to groups II and III, respectively. The lettuce extract combined with the doses of B[a]p were administered to groups IV and V. The experiment was performed again under the same conditions to test the effect of chard extract. Urine samples were tested by means of the Ames assay. The results show that the mutagenic activity of the urine samples from groups treated with B[a]p was reduced when the treatment also included any vegetable extract.     

Short-term toxicity study of allyl isothiocyanate in rats

Allyl isothiocyanate (AITC) was given in doses of 0, 10, 20, or 40 mg/kg (5 days/week) by oral intubation to male rats for up to 6 weeks. The highest dosage level caused a decrease in body weight, thymus weight, blood glucose and serum globulin levels. Haematological examination revealed an increased percentage of neutrophils and a decreased percentage of lymphocytes after treatment for 2 weeks. Increased liver and adrenal weights were found in all test groups. Renal dysfunction was indicated by increased urinary aspartate amino-transferase activity, reduced urine volume and changes in the specific gravity of the urine. Histopathological changes were observed in the kidneys of animals at dosages of 20 and 40 mg/kg and in the livers of animals at the highest dosage level.     

Hypoglycemic effects of black glutinous corn polysaccharides on alloxan-induced diabetic mice

To investigate substances from corn with the potential to affect blood sugar levels, black glutinous corn polysaccharides (BGCP) were isolated and evaluated for hypoglycemic activity in alloxan-induced diabetic mice. Mice were administered daily doses of 800, 500 or 200 mg/kg BGCP for 4 weeks. Blood glucose, serum insulin levels, body weight and the organ weight of liver, kidney, spleen and thymus were measured. All three BGCP-treated groups showed reduced blood glucose levels, and treatment with 800 mg/kg resulted in greater hypoglycemic effects than treatment with lower doses. At week 4 of the trial, mice receiving 800 or 500 mg/kg BGCP showed blood glucose levels that were significantly lower (P < 0.05) than untreated diabetic control mice. Administration of alloxan led to significant loss of body weight after 2, 3 and 4 weeks. BGCP treatment did not affect the weight of the thymus and spleen compared to untreated diabetic control mice. The weight of the liver decreased and the weight of kidney increased in alloxan-treated diabetic mice, but kidney weight did not increase in diabetic mice treated with 800 mg/kg BGCP.     

Piperine reverses high fat diet-induced hepatic steatosis and insulin resistance in mice

This study examined the effect of piperine on hepatic steatosis and insulin resistance induced in mice by feeding a high-fat diet (HFD) for 13 weeks and elucidated potential underlying molecular mechanisms. Administration of piperine (50 mg/kg body weight) to mice with HFD-induced hepatic steatosis resulted in a significant increase in plasma adiponectin levels. Also, elevated plasma concentrations of insulin and glucose and hepatic lipid levels induced by feeding a HFD were reversed in mice when they were administered piperine. However, piperine did not reduce body weight and other biochemical markers to an extent where they became equal to the levels found in the CD-fed mice. Piperine reversed HFD-induced down-regulation of adiponecitn-AMP-activated protein kinase (AMPK) signalling molecules which play an important role in mediating lipogenesis, fatty acid oxidation and insulin signalling in the livers of mice. The expressions of lipogenic target genes were decreased, whereas the expression of carnitine palmitoyltransferase 1 (CPT1) gene involved in fatty acid oxidation was increased in the livers of the Pin50 group. Piperine significantly decreased the phosphorylation of insulin receptor substrate-1 (IRS-1) compared with the HFD-fed mice. Administration of piperine appeared to reverse preexisting HFD-induced hepatic steatosis and insulin resistance, probably by activation of adiponectin-AMPK signalling in mice.     

灵芝肽对乙醇诱导肝损伤小鼠的保护作用

目的：研究灵芝肽(GLP)对乙醇诱导的肝损伤小鼠的保护作用。方法：将60 只小鼠随机分成6 组,每组10 只,分别为正常组,乙醇肝损伤模型组,硫普罗宁(Tiopronin)阳性对照组,GLP 低、中和高剂量组。每天灌胃一次,GLP 低、中、高剂量组分别灌胃GLP 60、120、180mg/kg bw,阳性对照组灌胃硫普罗宁溶液50mg/kg bw,正常组、模型组灌胃等量生理盐水;每次给药3h 后,除正常组外,各组均灌胃50% 乙醇16mL/kg bw,连续灌胃2 周,建立小鼠酒精性肝损伤模型。通过脏器质量和体质量计算肝、脾脏指数;按照试剂盒的方法测定小鼠血清中谷丙转氨酶(ALT)、谷草转氨酶(AST)、甘油三酯(TG)含量,肝匀浆中超氧化物歧化酶(SOD)活力、丙二醛(MDA)含量、还原性谷胱甘肽(GSH)含量等指标。结果：60mg/kg bw GLP 能极显著降低酒精性肝损伤所引起的ALT、AST 活性和MDA、TG 含量的升高(P ＜ 0.01),有效地拮抗肝脏中SOD的活性与GSH含量的降低(P ＜ 0.05～0.01)。结论：60mg/kg bw GLP 对乙醇诱导的肝损伤小鼠有显著的保护作用,180mg/kg bw GLP 的保肝效果好于50mg/kg bw硫普罗宁。     

西洋参片对小鼠抗疲劳作用的实验研究

目的：研究西洋参片的抗疲劳作用。方法：将小鼠按体重随机分为对照组和低、中、高剂量组。低、中、高三个剂量组分别灌胃给予67、133、200mg／kg的西洋参片30d，对照组给蒸馏水。测定小鼠游泳时间及血乳酸、尿素氮、肝糖原等指标。结果：西洋参片的三个剂量组均能显著提高小鼠肝糖原的储备量；降低小鼠游泳后血乳酸曲线下面积；降低运动后血清尿素氮含量，加速体内尿素氮的清除速率，提高小鼠的游泳时间。结论：西洋参片具有抗疲劳作用。     

Cystone,an ayurvedic herbal drug imparts protection to the mice against the lethal effects of gamma-radiation: a preliminary study

The effect of 5, 10, 20, 40, 60, 80, 100, 120, and 160 mg/kg body weight (b.wt.) of aqueous extract of cystone (an ayurvedic herbal medicine) administered intraperitoneally was studied on the radiation-induced mortality in mice exposed to 10 Gy of gamma-radiation. Treatment of mice with different doses of cystone, consecutively for five days before irradiation, delayed the onset of mortality and reduced the symptoms of radiation sickness when compared with the non-drug treated irradiated controls. The pretreatment of mice with different doses of cystone before exposure to 10 Gy of gamma-radiation resulted in a dose-dependent elevation in the survival up to 40 mg/kg b.wt., where the highest number of survival (55.55%) was observed by 30 days post irradiation, when compared with the 10 Gy irradiated control (6.66%). Thereafter, the number of survivors declined and reached a nadir at 160 mg/kg, where no survivors could be observed. The optimum protection against irradiation was observed for 40 mg/kg cystone, where the highest number of survivors were reported by 30 days post irradiation and it was 8.34-fold greater than that of the irradiated control group.     

Ninety-day dietary toxicity study of mulberry leaf extract in rats

Mulberry leaf extract was studied toxicologically in male and female SD rats. The extract was administered orally at concentrations of 0% (control group), 0.1%, 0.4% and 1% in basal diet for 90 days. No remarkable change in test animals of both sexes was observed in terms of body weight gain or at necropsy. Hematology and blood chemistry revealed no abnormalities. Pathological examination revealed no toxic change in any organ observed. These findings indicate that dietary intake of 1% mulberry leaf extract for 90 days (884.5 mg/kg/day for males and 995.7 mg/kg/day for females as mean daily intake) causes no toxicological change in rats.     

Reverse Effect of Opuntia ficus‐indica L. Juice and Seeds Aqueous Extract on Gastric Emptying and Small‐Bowel Motility in Rat

This study was conducted to compare the effects of juice and seeds on gastric emptying, small‐bowel motility and intestinal ion transport. Separate groups of rats were randomized to receive NaCl, increasing doses of juice (5, 10, and 20 mL/kg, b.w.) or seeds aqueous extract (100, 200, and 400 mg/kg, b.w.). Simultaneously, two other groups were received, the reference drugs; clonidine (1 mg/kg) and yohimbine (2 mg/kg). The charcoal meal was used as a suspension for gastrointestinal motility test. The purgative action of juice was confirmed using the loperamide (5 mg/kg, p.o.) induced constipation. To evaluate the antisecretory effect, we were used as a hypersecretion agent, the castor oil at the dose of 5 mL/kg. Compared to the control and standard groups, we were showed that the prickly pear has an opposite effect on small‐bowel motility and gastric emptying. Indeed, the juice at various doses has a laxative effect of gastrointestinal transit in healthy and constipated‐rats. However, the aqueous extract of the seeds leads to a reduction of motility in normal rats which gives it a remarkable antidiarrhoeal activity, a notable intestinal fluid accumulation decline and electrolyte concentrations reestablishment. Moreover, orally juice administered at different doses accelerated the stomach emptying time in contrast to the seeds aqueous extract. More importantly, a significant variation in the phytochemical constituents levels between juice and seeds was found. These findings confirm the reverse therapeutic effects of this fruit in the treatment of digestive disturbances such as difficulty stool evacuation and massive intestinal secretion, likewise, the gastric emptying process perturbation.     

Cystone,an ayurvedic herbal drug imparts protection to the mice against the lethal effects of γ‐radiation: A preliminary study

The effect of 5, 10, 20, 40, 60, 80, 100, 120, and 160 mg/kg body weight (b.wt.) of aqueous extract of cystone (an ayurvedic herbal medicine) administered intraperitoneally was studied on the radiation‐induced mortality in mice exposed to 10 Gy of γ‐radiation. Treatment of mice with different doses of cystone, consecutively for five days before irradiation, delayed the onset of mortality and reduced the symptoms of radiation sickness when compared with the non‐drug treated irradiated controls. The pretreatment of mice with different doses of cystone before exposure to 10 Gy of γ‐radiation resulted in a dose‐dependent elevation in the survival up to 40 mg/kg b. wt., where the highest number of survival (55.55%) was observed by 30 days post irradiation, when compared with the 10 Gy irradiated control (6.66%). Thereafter, the number of survivors declined and reached a nadir at 160 mg/kg, where no survivors could be observed. The optimum protection against irradiation was observed for 40 mg/kg cystone, where the highest number of survivors were reported by 30 days post irradiation and it was 8.34‐fold greater than that of the irradiated control group.     

First evaluation of the antimutagenic effect of mangaba fruit in vivo and its phenolic profile identification

The chemical composition and functional effects of mangaba fruit pulp were evaluated through a multi-endpoint assay in mice, consisting of the bone marrow micronucleus test, gut micronucleus test, and the apoptosis, oxidative stress, and comet assays. Mangaba fruit pulp was administered in three doses, 10, 20, and 40 ml/kg body weight (b.w.), by gavage to male Swiss mice against doxorubicin and dimethylhydrazine-induced mutagenicity. The phenolic profile of the mangaba fruit pulp was evaluated by HPLC, and seven compounds were identified: gallic acid, catechin, chlorogenic acid, vanillic acid, o-coumaric acid, rosmarinic acid, and rutin. The in vivo tests revealed that mangaba fruit pulp showed no toxic/mutagenic effects in any of the assays performed, and also showed protective effects at all endpoints. At the three administered extract concentrations, the main results about the protective effects were as follows: bone marrow micronucleus test (42.33, 58.14, and 77.21%), micronucleus gut test (34.21, 63.15, and 78.07%), and apoptosis index (57.5, 43.68, and 65.52%). This study provides scientific evidence for the antimutagenic potential of mangaba fruit pulp and emphasizes its potential as a functional food with widespread applicability in the food industry.