Effects of capsaicin on rat liver S9-mediated metabolism and DNA binding of aflatoxin

At concentrations of 25, 50, and 100 microM, capsaicin, which is the major component in various aspects of Capsicum hot peppers, decreased the binding of aflatoxin (AFB1) to calf thymus DNA by 19%, 44%, and 71%, respectively, in incubations with rat liver S9. At concentrations of 50 and 100 microM, capsaicin decreased the formation of AFB-DNA adducts (AFB1-N7-Gua) by 53% and 75% as determined by high-pressure liquid chromatography (HPLC). HPLC analysis of organo-soluble fractions showed that these effects correlated with a concentration-dependent decrease in S9-mediated metabolism of AFB1 by capsaicin. Capsaicin also altered the formation of water-soluble conjugates of AFB1. This was indicated by a decrease in radioactivity in water-soluble fractions and in glutathione conjugates of AFB1 analyzed by HPLC. These results suggest that capsaicin inhibited the biotransformation of AFB1 by modifying Phase I hepatic enzyme activity.     

Garlic and garlic-derived compounds inhibit human squalene monooxygenase

Although extracts of garlic inhibit cholesterol biosynthesis in cultured hepatocytes, the inhibitory components of garlic and the site or sites of inhibition in the cholesterol biosynthetic pathway have not been established. To elucidate potential mechanisms of inhibition, we examined the effect of fresh garlic extract and 16 water- or lipid-soluble compounds derived from garlic on purified recombinant human squalene monooxygenase. Squalene monooxygenase catalyzes the second and likely rate-limiting step in the downstream pathway for cholesterol biosynthesis. A 50% inhibitory concentration (IC(50)) of squalene epoxidation was achieved with 1 g/L of fresh garlic extract; of the 16 garlic compounds tested, only selenocystine (IC(50) = 65 micromol/L), S-allylcysteine (IC(50) = 110 micromol/L), alliin (IC(50) = 120 micromol/L), diallyl trisulfide (IC(50) = 195 micromol/L), and diallyl disulfide (IC(50) = 400 micromol/L) substantially inhibited the enzyme. Kinetic analysis showed that the inhibition by garlic and by these compounds was slow and irreversible, suggestive of covalent binding to the enzyme; the ability of thiol-containing compounds such as glutathione and 2,3-dimercaptopropanol to prevent and reverse the inhibition indicated that the garlic compounds were reacting with sulfhydryl groups on the protein. Dithiols were better reversal agents than monothiols, further suggesting that these inhibitors bind to the proposed vicinal sulfhydryls present on this enzyme. These results indicate that squalene monooxygenase may be one of the target enzymes through which garlic inhibits cholesterol biosynthesis.     

Carnitine alters binding of aflatoxin to DNA and proteins in rat hepatocytes and cell-free systems.

The objective of this study was to determine effects of L-carnitine on aflatoxin B(1) (AFB(1))-DNA adduct formation in isolated rat hepatocytes, its dose response, specificity and mode of action. All experiments were conducted in either freshly isolated rat hepatocytes or cell-free systems. There was negative linear correlation between the dosage of carnitine and formation of [(3)H]AFB(1)-DNA adducts in the hepatocytes; however, the partitioning of AFB(1) into cellular compartments was not affected by carnitine. The attenuating effect of carnitine on AFB(1)-DNA adduct formation was also present in a cell-free system, but there was lack of specificity because acetylcarnitine and gamma-aminobutyric acid (GABA) were equally effective. Carnitine appears to interfere with bioactivation of AFB(1) and binding of AFB(1)-epoxide to DNA. On the contrary, carnitine enhanced the binding of AFB(1) and its epoxide to microsomal proteins, plasma proteins and bovine serum albumin. These results indicate that carnitine diverts AFB(1)-epoxide away from DNA by promoting binding to proteins. We conclude that modulation of AFB(1) binding to proteins and DNA by carnitine alters the carcinogenic and hepatotoxic potential of AFB(1) and poses concerns about the human AFB(1)-exposure data based on the AFB(1)-albumin adduct concentrations as a biomarker.     

Effect of purified allicin, the major ingredient of freshly crushed garlic, on cancer cell proliferation

The diverse health benefit effects of garlic include its anticancer activity. However, very little is known about such activity of isolated garlic compounds, among which allicin (the major ingredient of crushed garlic) has been the least studied. The aim of this work was to determine whether pure allicin exhibits the antiproliferative effect reported for garlic in in vitro models. Allicin, but not its precursor alliin, inhibited proliferation of human mammary (MCF-7), endometrial (Ishikawa), and colon (HT-29) cancer cells (50% inhibitory concentration = 10-25 microM). Two of three tested primary lines of human fibroblasts displayed a similar response to allicin (50% inhibitory concentration = 16-40 microM), whereas the third line was almost unaffected by this compound. The pure allicin and water extract of garlic powder with equivalent allicin concentrations displayed a similar potency, suggesting that allicin is responsible for the antiproliferative effect of the extract. The growth inhibition was accompanied by accumulation of cells in the G0/G1 and G2/M phases of the cell cycle (MCF-7 cells) and not by a significant increase in cell death. Allicin caused a transient drop in the intracellular glutathione (GSH) level, the magnitude and kinetics of which significantly varied depending on cell type. The extent of the decrease in GSH levels correlated well (r = 0.75) with the growth inhibitory activity of allicin. On the basis of these findings, we suggest that allicin plays a major role in the antiproliferative effect of water-soluble garlic preparations and that this effect may be attributed to the ability of allicin to transiently deplete the intracellular GSH level.     

Antidiabetic effects of ajoene in genetically diabetic KK-A(y) mice

Antidiabetic effects of ajoene, derived from garlic, were investigated in genetically diabetic KK-A(y) mice. Four-week-old male KK-A(y) mice were kept on a laboratory diet containing 0.02 or 0.05% of ajoene for 8 wk. The elevation of water intake was suppressed depending on ajoene intake. The levels of plasma glucose in the 0.05% ajoene-containing diet group was significantly suppressed to 73.8% compared with the control group at the 8th wk. Similarly, the plasma triglyceride level was significantly suppressed. It is suggested that hyperglycemia and hypertriglyceridemia are suppressed by ajoene treatment.     

Effects of carotenoids on aflatoxin B1-induced mutagenesis in S. typhimurium TA 100 and TA 98

The effects of beta-carotene, canthaxanthin, and extracts of tomato paste (containing lycopene) and orange juice (containing cryptoxanthin) on aflatoxin B1 (AFB1)-induced mutagenesis in S. typhimurium TA 100 and TA 98 were investigated. Inhibition of mutagenesis was studied during and following completion of AFB1 metabolism (i.e., after the addition of menadione), thereby permitting separate examination of the metabolic activation and phenotypic expression phases. Each experimental carotenoid, except lycopene, inhibited AFB1-induced mutagenesis in both tester strains. Cryptoxanthin was the most potent inhibitor, being at least an order of magnitude more potent than the other carotenoids. Inhibition by beta-carotene and canthaxanthin was more prominent during the activation phase, whereas cryptoxanthin was more effective during the subsequent phenotypic expression phase. These inhibitory effects were not dependent on conversion to retinol.     

Modified mutagen metabolism in Schistosoma hematobium-infested organisms

The relationship between parasite infestation and chemical mutagen metabolism was investigated in this study. Schistosoma hematobium, long associated with increased incidence of bladder cancer in humans, was chosen as a model parasite. Urine samples, serum samples, and liver tissue extracts (S-9) from infested and control hamsters were used with the Ames Salmonella/microsome test to follow 3,3'-dichlorobenzidine (DCB), aflatoxin B1 (AFB1), and 2-acetylaminofluorene (AAF) mutagenicity. Liver S-9 preparations from infested and control hamsters showed little difference in activation potential for DCB and AFB1. Aroclor 1254-induced rat liver S-9, however, was remarkably efficient at reducing the mutagenicity of DCB. This process was reversible by beta-glucuronidase (BG). Studies on infested and control hamsters indicated increased BG activity in serum and urine. Urine concentrates (UC) from infested and control animals were not mutagenic by themselves, but did enhance the mutagenicity of AAF and DCB in the presence of S-9 and BG. Urine concentrates from infested animals showed greater enhancement of DCB mutagenicity than did UC from control animals. These data suggest that increased BG and unknown urinary factors in infested hamsters play a role in altering chemical mutagen activity.     

半枝莲对AFB1致肝细胞凋亡及脂质过氧化损伤的保护作用

目的：探讨半枝莲对AFB1致体外肝细胞毒性的保护作用及其机制。方法：通过采用四甲基偶氮唑（MTT）比色法检测AFB1对人肝癌细胞株Huh7.5细胞的生长抑制率,再用MTT法观察半枝莲作用下AFB1诱导的Huh7.5细胞增殖功能的影响,然后检测细胞内丙二醛含量（MDA）、红细胞超氧化物歧化酶（SOD）的水平以观察半枝莲对AFB1引起的Huh7.5细胞凋亡及脂质过氧化损伤的保护作用。结果：AFB1能显著抑制Huh7.5细胞增殖,IC50为15μg/mL;而半枝莲能显著抑制AFB1暴露细胞的凋亡（P〈0.01）。半枝莲能明显降低AFB1作用下肝细胞内MDA含量,提高其SOD活性,与对照组比较差异有显著性（P〈0.01）。结论：半枝莲对AFB1致Huh7.5细胞损伤具有保护作用,其机制与抑制肝细胞凋亡及对抗脂质过氧化有关。     

Protective Effects Induced by a Hydroalcoholic Allium sativum Extract in Isolated Mouse Heart

The aim of the present study was to investigate the possible protective effects of a garlic hydroalcoholic extract on the burden of oxidative stress and inflammation occurring on mouse heart specimens exposed to E. coli lipopolysaccharide (LPS), which is a well-established inflammatory stimulus. Headspace solid-phase microextraction combined with the gas chromatography–mass spectrometry (HS-SPME/GC–MS) technique was applied to determine the volatile fraction of the garlic powder, and the HS-SPME conditions were optimized for each of the most representative classes of compounds. CIEL*a*b* colorimetric analyses were performed on the powder sample at the time of delivery, after four and after eight months of storage at room temperature in the dark, to evaluate the color changing. Freshly prepared hydroalcoholic extract was also evaluated in its color character. Furthermore, the hydroalcoholic extract was analyzed through GC–MS. The extract was found to be able to significantly inhibit LPS-induced prostaglandin (PG) E₂ and 8-iso-PGF_2α levels, as well as mRNA levels of cyclooxygenase (COX)-2, interleukin (IL)-6, and nuclear factor-kB (NF-kB), in heart specimens. Concluding, our findings showed that the garlic hydroalcoholic extract exhibited cardioprotective effects on multiple inflammatory and oxidative stress pathways.     

The protective effect of hydrated sodium calcium aluminosilicate against the adverse effects of aflatoxin B1 on D. melanogaster

The main aim of this study was to investigate the effects of Aflatoxin B1 (AFB1) and Aflatoxin B1 + hydrated sodium calcium aluminosilicate (HSCAS) on various developmental stages of Drosophila melanogaster. Different concentrations of AFB1 and HSCAS + AFB1 were administered during the developmental periods of the fly (egg, larvae and pupae). When the F1 progeny of control and application groups were compared, AFB1 was found to extend the process of metamorphosis and decrease the total number of offspring. However, these negative effects were inhibited with HSCAS treatment at different concentrations (5.0 and 10.0 ppm). These results suggest that HSCAS could effectively inhibit AFB1-induced abnormalities in the developmental stages of D. melanogaster.     

Synthesis, antibacterial, antifungal and anti-HIV activities of norfloxacin mannich bases

Mannich bases of norfloxacin were synthesized by reacting them with formaldehyde and several isatin derivatives. Their chemical structures have been confirmed by means of their IR, 1H-NMR data and by elemental analysis. Investigation of in vitro antimicrobial activity of compounds was done by the agar dilution method against 28 pathogenic bacteria, eight pathogenic fungi and anti-HIV activity against replication of HIV-1 (III B) in MT-4 cells. The in vivo antibacterial efficacy of selected derivatives was determined using a mouse infection model. All the synthesized compounds are more active than norfloxacin against the 13 bacteria tested. The compounds are also more active than the standard drug clotrimazole against Histoplasma capsulatum. Two compounds S-8 and S-9 have shown inhibition against HIV-1 (III B) with EC(50) values of 11.3 and 13.9 microgram/mL, respectively. In the mouse protection test, two compounds S-4 (ED(50): 1.25 mg/kg) and S-9 (ED(50): 1.62 mg/kg) are more active than norfloxacin (ED(50): 6mg/kg). Among the compounds tested, 1-ethyl-6-fluoro-1, 4-dihydro-4-oxo-7[[N(4)-[5'-bromo-3'-(4'-amino-5'-trimethoxybenzylpyr imidin-2'-yl]-imino-1'-isatinyl]methyl]N(1)-piperazinyl]-3-q uinoline carboxylicacid (S-9) showed promising activity in all the three tests.     

Antiatherosclerotic effects of licorice extract supplementation on hypercholesterolemic patients: increased resistance of LDL to atherogenic modifications, reduced plasma lipid levels, and decreased systolic blood pressure

OBJECTIVE: We previously demonstrated the beneficial effects of dietary flavonoids derived from the ethanolic extract of licorice root against atherosclerotic lesion development in association with inhibition of low-density lipoprotein (LDL) oxidation in atherosclerotic mice. Administration of licorice extract to normolipidemic subjects also inhibited LDL oxidation. In the present study, we extended our investigation to analyze the antiatherogenic effects of licorice-root extract consumption in moderately hypercholesterolemic patients. METHODS: Supplementation of licorice root extract (0.1 g/d) to patients for 1 mo was followed by an additional 1 mo of placebo consumption. RESULTS: Licorice consumption 1) reduced patients' plasma susceptibility to oxidation (by 19%); 2) increased resistance of plasma LDL against three major atherogenic modifications: oxidation (by 55%), aggregation (by 28%), and retention, estimated as chondroitin sulfate binding ability (by 25%); 3) reduced plasma cholesterol levels (by 5%), which was due to a 9% reduction in plasma LDL cholesterol levels; and 4) reduced (by 14%) plasma triacylglycerol levels. After the 1 mo of placebo consumption, these parameters reversed toward baseline levels. Licorice extract supplementation also reduced systolic blood pressure by 10%, which was sustained during the placebo consumption. CONCLUSIONS: Dietary consumption of licorice-root extract by hypercholesterolemic patients may act as a moderate hypocholesterolemic nutrient and a potent antioxidant agent and, hence against cardiovascular disease.     

Equol: a comparison of the effects of the racemic compound with that of the purified S-enantiomer on the growth, invasion, and DNA integrity of breast and prostate cells in vitro

It has been postulated that the R- and S-equol enantiomers have different biological properties given their different binding affinities for the estrogen receptor. S-(-)equol is produced via the bacterial conversion of the soy isoflavone daidzein in the gut. We have compared the biological effects of purified S-equol to that of racemic (R and S) equol on breast and prostate cancer cells of varying receptor status in vitro. Both racemic and S-equol inhibited the growth of the breast cancer cell line MDA-MB-231 (> or = 10 microM) and the prostate cancer cell lines LNCaP (> or = 5 microM) and LAPC-4 (> or = 2.5 microM). The compounds also showed equipotent effects in inhibiting the invasion of MDA-MB-231 and PC-3 cancer cells through matrigel. S-equol (1, 10, 30 microM) was unable to prevent DNA damage in MCF-7 or MCF-10A breast cells following exposure to 2-hydroxy-4-nonenal, menadione, or benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide. In contrast, racemic equol (10, 30 microM) prevented DNA damage in MCF-10A cells following exposure to 2-hydroxy-4-nonenal or menadione. These findings suggest that racemic equol has strong antigenotoxic activity in contrast to the purified S-equol enantiomer implicating the R-, rather than the S-enantiomer as being responsible for the antioxidant effects of equol, a finding that may have implications for the in vivo chemoprotective properties of equol.     

Synthesis and evaluation of 9-anilinothiazolo[5,4-b]quinoline derivatives as potential antitumorals

Five new 9-anilinothiazolo[5,4-b]quinoline derivatives (compounds 5, 7, 9, 10, 11) have been prepared. Some of the compounds were prepared by coupling properly substituted anilines to the novel compound 9-chloro-2-(methylthio)thiazolo[5,4-b]quinoline. Of these, compound 7 (9-anilino-2-[[2-(N,N-diethylamino)ethyl]amino]thiazolo[5,4-b]quinoline) showed the best cytotoxic activity in several cell lines. All compounds demonstrated DNA binding in nanomolar range. Compound 7 inhibited the (14)C-thymidine incorporation into DNA. Results indicate that these derivatives deserve more considerations as potential antitumoral drugs.     

Inhibition of carcinogen-induced DNA damage in rat liver and colon by garlic powders with varying alliin content

The present study was designed to investigate the protective efficiency of three garlic powders, obtained from bulbs grown in soils with different levels of sulfur fertilization, against DNA damage. Increasing fertilization of soil resulted in an increased alliin content of the powders. Garlic powders were administered to rats for 2 weeks (5% of the diet) and their antigenotoxic effects were examined in the liver and the colon using the comet assay. Consumption of the different garlic powders induced a 35-60% reduction in DNA damage induced by N-nitrosodimethylamine (NDMA) in rat liver. Increased alliin content of the garlic powder was associated strongly with a proportional decrease in NDMA induced DNA alteration. DNA damage induced by aflatoxin B1 in the liver or by 1,2-dimethylhydrazine in the colon were also decreased strongly by the three garlic powders but these decreases were not correlated to the alliin content of the garlic powders. Feeding garlic powders did not modify the genotoxic activity of the direct-acting carcinogen methylnitrosourea in the colon. Part of our results supports evidence that fertilization can have an impact on the protective capacity of garlic bulbs.     

Anti-genotoxic effect of hydrated sodium calcium aluminosilicate on genotoxicity to human lymphocytes induced by aflatoxin B1

The anti-genotoxic potential of hydrated sodium calcium aluminosilicate (HSCAS) was investigated using sister chromatid exchanges (SCEs) induced by aflatoxin B1 (AFB1) as genotoxic endpoint in human lymphocytes. Whole blood samples from two healthy male donors were used for this experiment and the effects of different concentrations of HSCAS (5 x 10(-6) and 1 x 10(-5) M) and AFB1 (1, 5 and 10 microM) were tested. The present results established that the frequencies of SCEs (at doses of 5 and 10 microM except for 1 microM) in lymphocytes were significantly increased by AFB1 compared to controls. When HSCAS was added alone at a molar ratio of 5 x 10(-6) and 1 x 10(-5), lymphocytes did not show significant increases in SCE frequencies, but SCE frequencies induced by the various concentrations of AFB1 could be significantly reduced by the presence of HSCAS (at both doses). In fact, HSCAS at 1 x 10(-5) M completely inhibited SCE formations caused by AFB1. These results suggest for the first time, that HSCAS can antagonize the ability of AFB1 to cause DNA damage that leads to the formation of SCEs.     

大蒜浸提液对小鼠细胞免疫功能影响研究

大蒜浸提液对小鼠细胞免疫功能影响研究李锋，王玉（兰州医学院预防医学系，７３００００）大蒜是一种营养价值很高的食品，含多种有效成分。近年来研究表明，大蒜具有明显的防癌抗癌、预防和控制心血管疾病、抗菌消炎及延缓衰老等作用［１，２］。为充分利用开发大蒜资源...     

大蒜粗提物降脂减肥作用研究

目的 对大蒜粗提物作为保健食品的降脂减肥作用进行评价，并初步研究其作用机理。方法 选用SD雄性大鼠．建立高血脂和肥胖模型．以卫生部《保健食品功能学评价程序和检验方法》为实验依据。结果 大蒜粗提物0．2、0．4和1．2g／kgB．W．剂量组能明显降低高血脂大鼠血清胆固醇(TC)含量：0．4和1．2g／kgB．W．剂量组能明显降低高血脂大鼠血清甘油三脂(TG)含量．同时也明显降低肥胖大鼠的体重、增重和体内脂肪湿重；1．2g／kgB．W．剂量组能明显降低肥胖大鼠的体脂比。结论 大蒜粗提物具有降脂减肥作用，其机理可能与调节机体脂质代谢有关。     

大蒜阻断亚硝胺合成机理的研究

用Saville法测定鲜大蒜、复水大蒜片、大葱、菜花和土豆五种提取液中巯基含量,用Griess氏法测定这五种提取液消除亚硝酸盐的效果,证实鲜大蒜提取液中巯基含量最高,且消除亚硝酸盐的效果最好。用高效液相色谱光导检测器(HPLC-PCD)分离分析证实,大蒜中的巯基化合物可与亚硝酸盐生成琉代亚硝酸酯类化合物。烯丙基硫醇是大蒜中所含的较特异的巯基化合物。用该化合物与亚硝酸钠反应而合成了一种新的化合物。经红外光谱测定、紫外光解实验和紫外/可见光(UV/Vis)光谱扫描,证实此新化合物为烯丙基硫代亚硝酸酯,从而说明大蒜中的巯基化合物通过结合亚硝酸盐面阻断了亚硝胺的合成。     

镰刀菌毒素与黄曲霉毒素的联合毒性研究--AFB1和DON的RDS实验

为了解黄曲霉毒素（ＡＦＢ１）与镰刀菌毒素的脱氧雪腐镰刀菌烯醇（ＤＯＮ）对ＤＮＡ损伤修复的影响,用化学物质诱导的细胞增殖的变化实验,（ｒｅｐｌｉｃａｔｉｖｅ ＤＮＡ ｓｙｎｔｈｅｓｉｓ,ＲＤＳ）实验进行研究。结果表明：ＡＦＢ１和ＤＯＮ均可诱导细胞分化的Ｓ期ＤＡＮ的合成,并且二者间存在交互作用。结果提示：ＡＦＢ１与ＤＯＮ在肿瘤的发生中既以遗传毒性物质的形式发挥作用,又以非遗传毒性物质的形式共同发挥作用