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1.
The most important active compound in garlic is alliin. Sulfur (S) fertilization was shown to significantly increase the alliin concentration in garlic cloves, while high nitrogen (N) levels had an adverse effect. The effect of graded N and S application on the storage life of garlic has been paid little attention so far. A bifactorial field trial with 4 levels of N and S was conducted in a randomized block design. At harvest, 40 bulbs per treatment were stored under terms comparable to the storage conditions in average households (20 °C, dry, and dim) for 83 days. Every 3 weeks, samples were analyzed for their alliin and water content. The alliin concentration in peeled garlic cloves increased during storage from on average 9.2 mg g(-1) dry weight at harvest to 21.4 mg g(-1) dry weight after 83 days of storage. S fertilization increased the alliin concentration by a factor of 2.3 from 11.4 mg g(-1) in the control treatment to 26.6 mg g(-1) dry weight at the highest S level of 45 kg ha(-1) after 83 days of storage. N fertilization decreased by a trend of the alliin content. Fertilizer rates had only a minor influence on water losses from bulbs at short-term storage. After 83 days of storage, water losses were by trend lower at higher S levels, and this relationship proved to be significant when no N was applied. Best quality in terms of high alliin contents was obtained during the entire storage time at an S level of at minimum 30 kg ha(-1) S if no N was applied. The results show that the physiological S demand of 15 kg ha(-1) S for optimum yield is lower than the S requirement of 30 kg ha(-1) S for a longer storage life. 相似文献
2.
Montaño A Beato VM Mansilla F Orgaz F 《Journal of agricultural and food chemistry》2011,59(4):1301-1307
The content of organosulfur compounds was determined in selected garlic cultivars grown at four locations in Andalusia, Spain. The organosulfur compounds studied were three γ-glutamyl peptides, namely, γ-l-glutamyl-S-(2-propenyl)-l-cysteine (GSAC), γ-l-glutamyl-S-(trans-1-propenyl)-l-cysteine (GSPC), and γ-l-glutamyl-S-methyl-l-cysteine (GSMC), and four cysteine sulfoxides (alliin, isoalliin, methiin, and cycloalliin). There was a significant effect of the location, cultivar, and garlic ecotype on individual organosulfur compound contents. Purple-type cultivars showed on average the highest contents of GSMC, GSAC, alliin, and methiin but the lowest isoalliin content. The impact of genotype was relatively high for GSAC, whereas this factor hardly contributed to the total variability in alliin and isoalliin content. Planting date had a significant effect on the content of alliin and isoalliin. Discriminant analysis evidenced the ability of organosulfur compounds to distinguish among garlic bulbs from different locations or ecotypes with 81 or 86% accuracy, respectively. 相似文献
3.
《Journal of plant nutrition》2013,36(10):1827-1839
Abstract Onion (Allium cepa L.) and garlic (Allium sativum L.) were among the earliest cultivated crops and have been popular in folk medicine for centuries. Alliins (cysteine sulfoxides) are the characteristic sulfur (S) containing secondary metabolites of Allium species like onions, shallot, garlic, leek and chives and they cause taste and sharpness and are criteria for the pharmaceutical quality. The influence of the S nutritional status on the content of secondary S containing metabolites was shown for different crops such as oilseed rape, mustard, nasturtium, and allium species. It was the aim of this study to investigate the influence of the S and nitrogen (N) supply on the alliin content of onion and garlic and to evaluate the significance for crop quality. In a greenhouse experiment three levels of N and S were applied in factorial combinations of 0, 50, and 250 mg pot?1 S and 250, 500, and 1000 mg pot?1 N. 8 plants were grown in a Mitscherlich pot containing 8 kg sand. Leaves and bulbs were sampled twice during the growth period in order to follow up translocation processes. The first sampling was carried out when leaves were developed, but bulb growth had not yet started and the second one during main bulb growth. An increasing S supply was related to an increasing alliin content in leaves and bulbs of both crops, whereas nitrogen fertilization had only a minor influence. The alliin content in bulbs could be doubled by S fertilization. A translocation of alliin from leaves to bulbs was found so that time of harvest has a strong influence on the alliin content. At the beginning of plant development high alliin contents were found in leaves, while with bulb development they were translocated into this plant organ. The results show that the potential health benefits of Allium species could be distinctly improved by S fertilization. 相似文献
4.
Quantitative determination of allicin in garlic: supercritical fluid extraction and standard addition of alliin 总被引：2，自引：0，他引：2
A quantitative method is described for the determination of allicin (2-propene-1-sulfinothioic acid S-2-propenyl ester) in garlic, using standard additions of alliin (l-(+)-S-allylcysteine sulfoxide) in conjunction with supercritical fluid extraction (SFE) and high performance liquid chromatography analysis with UV-vis absorbance detection. Optimum CO(2)-SFE conditions provided 96% recovery for allicin with precision of 3% (RSD) for repeat samples. The incorporation of an internal standard (allyl phenyl sulfone) in the SFE step resulted in a modest improvement in recovery (99%) and precision (2% RSD). Standard additions of alliin were converted to allicin in situ by endogenous alliinase (l-(+)-S-alk(en)ylcysteine sulfoxide lyase, EC 4.4.1.4). Complete conversion of the spiked alliin to allicin was achieved by making additions after homogenization-induced conversion of the naturally occurring cysteine sulfoxides to thiosulfinates had taken place, thus eliminating the likelihood of competing reactions. Concentration values for allicin determined in samples of fresh garlic (Allium sativum L. and Allium ampeloprasum) and commercially available garlic powders (Allium sativum L.) by standard addition of alliin were found in all cases to be in statistical agreement (95% confidence interval) with values determined using a secondary allicin standard (concentration determined using published extinction coefficients). This method provides a convenient alternative for assessing the amount of allicin present in fresh and powdered garlic, as alliin is a far more stable and commercially prevalent compound than allicin and is thus more amenable for use as a standard for routine analysis. 相似文献
5.
To investigate whether the regulation of garlic allyl sulfides on biotransformation enzyme expression is tissue-specific, the expression of cytochrome P450 2B1 (CYP 2B1) and the placental form of glutathione S-transferase (PGST) in liver, lung, and intestine, which are the three major organs responsible for drug metabolism, was examined. Rats were orally administrated 0.5 or 2 mmol/kg BW diallyl sulfide (DAS) or 0.5 mmol/kg BW diallyl disulfide (DADS) or diallyl trisulfide (DATS) three times per week for 6 weeks. The final body weights and the body weight ratio of liver and lung were not changed by any of these three allyl sulfide treatments as compared to the control rats. An 11- and 12-fold increase of 7-pentoxyresorufin O-dealkylase (PROD) activities was noted in rats treated with 0.5 or 2 mmol/mg BW DAS, respectively, as compared with the controls (P < 0.05). In contrast, DADS and DATS significantly increased hepatic PGST activity toward ethacrynic acid by 30 and 40%, respectively, as compared with the control rats (P < 0.05). An increase in PGST activity was only noted at 2 mmol/kg BW DAS group (P < 0.05). In addition, similar increases in PGST activity due to DADS and DATS were also noted in lung and jejunum tissue (P < 0.05). Immunoblot assay shows that the changes in CYP 2B1 and PGST proteins due to the three garlic allyl sulfide treatments on liver, lung, and jejunum were consistent with those observed for PROD and PGST activities. Northern blot further revealed that the DADS and DATS increased PGST mRNA levels in both liver (2.9- and 3.0-fold, respectively) and lung (4.1- and 2.6-fold, respectively) and DAS dose-dependently increased CYP 2B1 mRNA levels in the liver. Garlic allyl sulfides differentially induced CYP 2B1 and PGST expression, and this up-regulation of these two biotransformation enzymes is tissue-specific. 相似文献
6.
氮硫互作提高大蒜氮、硫含量及其关键同化酶活性 总被引：1，自引：1，他引：0
7.
Differential effects of garlic oil and its three major organosulfur components on the hepatic detoxification system in rats. 总被引：18，自引：0，他引：18
Chih-Chung Wu Lee-Yan Sheen Haw-Wen Chen Wei-Wen Kuo Shun-Jen Tsai Chong-Kuei Lii 《Journal of agricultural and food chemistry》2002,50(2):378-383
The objective of this study was to compare the modulatory effect of garlic oil and its three organosulfur compounds, diallyl sulfide (DAS), diallyl disulfide (DADS), and diallyl trisulfide (DATS), on rat hepatic detoxification enzyme activity, and protein and mRNA expression. Rats were orally administered garlic oil (80 or 200 mg/kg bw), DAS (20 or 80 mg/kg bw), DADS (80 mg/kg bw), or DATS (70 mg/kg bw) three times a week for 6 weeks. Control rats received corn oil. According to the results, garlic oil and DAS in dosages of 200 and 80 mg/kg bw, respectively, significantly increased pentoxyresorufin O-dealkylase (PROD) activity as compared with the that of the control rats (P < 0.05). In contrast, N-nitrosodimethylamine demethylase activity in rats that received DADS and DATS was significantly lower than that in the control rats (P < 0.05). Ethoxyresorufin O-deethylase and erythromycin demethylase activities were not influenced by garlic oil, DAS, DADS, or DATS. To the phase II enzyme, garlic oil, DADS, and DATS significantly increased the glutathione S-transferase (GST) activity toward ethacrynic aicd (P < 0.05). Immunoblot assay showed that the protein contents of cytochrome P450 1A1, 2B1, and 3A1 were increased by garlic oil and each of three allyl sulfides, and the change among the allyl sulfides was in the order of DAS > DADS > DATS. The placental form of GST (PGST) level was also increased by garlic oil and the three allyl sulfides, but the increase among the allyl sulfides was DATS congruent with DADS > DAS. P450 2E1, however, was suppressed by each garlic component. Northern blot results indicated that the changes in P450 1A1, 2B1, 3A1, and PGST mRNA levels by garlic components were similar to those noted in the protein levels. These results indicate that the modulatory effect of garlic oil on hepatic drug-metabolizing enzymes can be attributed to its three major allyl sulfide components DAS, DADS, and DATS. These three allyl sulfides vary in modulatory activity, and this variation is related to the number of sulfur atoms in the molecule. 相似文献
8.
We determined the changes in the contents of three gamma-glutamyl peptides and four sulfoxides in garlic cloves during storage at -3, 4, and 23 degrees C for 150 days using a validated high-performance liquid chromatography method that we reported recently. When garlic was stored at 4 degrees C for 150 days, marked conversion of the gamma-glutamyl peptides, gamma-L-glutamyl-S-allyl-L-cysteine and gamma-L-glutamyl-S-(trans-1-propenyl)-L-cysteine (GSPC), to sulfoxides, alliin and isoalliin, was observed. Interestingly, however, when garlic was stored at 23 degrees C, a decrease in GSPC and a marked increase in cycloalliin, rather than isoalliin, occurred. To elucidate in detail the mechanism involved, the conversion of isoalliin to cycloalliin in both buffer solutions (pH 4.6, 5.5, and 6.5) and garlic cloves at 25 and 35 degrees C was examined. Decreases in the concentration of isoalliin in both the solutions and the garlic cloves during storage followed first-order kinetics and coincided with the conversion of cycloalliin. Our data indicated that isoalliin produced enzymatically from GSPC is chemically converted to cycloalliin and that the cycloalliin content of garlic cloves increases during storage at higher temperature. These data may be useful for controlling the quality and biological activities of garlic and its preparations. 相似文献
9.
Two garlic subspecies (n = 11), Allium sativum L. var. opioscorodon (hardneck) and Allium sativum L. var. sativum (softneck), were evaluated for their free amino acid composition. The free amino acid content of garlic samples analyzed ranged from 1121.7 to 3106.1 mg/100 g of fresh weight (mean = 2130.7 +/- 681.5 mg/100 g). Hardneck garlic had greater methiin, alliin, and total free amino acids contents compared to softneck garlic. The major free amino acid present in all but one subspecies was glutamine (cv. Mother of Pearl had aspartic acid as the major free amino acid). Cv. Music Pink garlic (a rocambole hardneck variety) contained the most methiin, alliin, and total free amino acids. The solid-phase extraction, alkylchloroformate derivatization, GC-FID, and GC-MS methods used in this study were simple and rapid, allowing 18 free amino acids in garlic to be separated within 10 min. 相似文献
10.
Citrus fruits are considered to be functional foods that promote good health. This study was carried out to assess the effect of oroblanco and grapefruit consumption on hepatic detoxification enzymes. Male Sprague-Dawley rats were provided with either regular drinking water (control) or experimental treatments of oroblanco juice, grapefruit juice, or a sugar mix for 6 weeks. After 1 week of treatment, half the animals in each group were injected with the procarcinogen 1,2-dimethylhydrazine. Grapefruit juice significantly increased activity and expression of the hepatic phase I enzyme, cytochrome P450 CYP1A1, with a marked trend toward enhanced NAD(P)H:quinone reductase (QR) activity. Oroblanco juice significantly increased glutathione S-transferase phase II enzyme activity along with CYP1A1 expression and a notable trend toward increased activity of both CYP1A1 and QR. These results suggest that these citrus fruits are bifunctional inducers, modulating both phase I and phase II drug-metabolizing enzymes to enhance hepatic detoxification. 相似文献
11.
Yao HT Lin JH Chiang MT Chiang W Luo MN Lii CK 《Journal of agricultural and food chemistry》2011,59(8):4306-4314
Adlay ( Coix lachryma-jobi L. var. ma-yuen Stapf) is a grass crop and is reported to protect against various diseases such as cancer. To investigate the effect of the ethanolic extract of adlay bran (ABE) on drug-metabolizing enzymes and glutathione-related antioxidant enzymes in rats, three groups of eight male Sprague-Dawley rats each were fed a control diet or a diet containing 5 or 10% ABE for 4 weeks. Significant decreases in microsomal cytochrome P-450 (CYP) 1A1-catalyzed ethoxyresorufin O-deethylation, CYP2C-catalyzed diclofenac 4-hydroxylation, CYP2D-catalyzed dextromethorphan O-demethylation, and CYP3A-catalyzed testosterone 6β-hydroxylation in the liver and CYP1A1-catalyzed ethoxyresorufin O-deethylation in the lungs of rats fed ABE were observed. Immunoblot analyses also showed decreases of CYP1A1, 1A2, 2C6, 2C11, 2D1, 2E1, 3A1, and 3A2 in the liver and CYP1A1 in the lungs. Furthermore, rats fed the 10% ABE diet had a higher glutathione content and glutathione peroxidase, glutathione reductase, and glutathione S-transferase activities in the lungs, but such an increase was not noted in the liver. Inhibition of various CYP-catalyzed enzyme reactions by ABE in rat and human liver microsomes had also been shown. The results of this study indicate that ABE feeding may suppress CYP enzyme activities and CYP protein expression in the liver and lungs of rats. Moreover, the increase of the antioxidant potential by ABE is tissue-specific. 相似文献
12.
13.
Effect of sesame seeds rich in sesamin and sesamolin on fatty acid oxidation in rat liver 总被引：7，自引：0，他引：7
Sirato-Yasumoto S Katsuta M Okuyama Y Takahashi Y Ide T 《Journal of agricultural and food chemistry》2001,49(5):2647-2651
Activities of enzymes involved in hepatic fatty acid oxidation and synthesis among rats fed sesame (Sesamum indicum L.) differing in lignan content (sesamin and sesamolin) were compared. Sesame seeds rich in lignans from two lines, 0730 and 0732, lines established in this laborary, and those from a conventional cultivar (Masekin) were employed. Seeds from the 0730 and 0732 lines contained sesamin and sesamolin at amounts twice those from Masekin. Sesame seeds were added at levels of 200 g/kg to the experimental diets. Sesame increased both the hepatic mitochondrial and the peroxisomal fatty acid oxidation rate. Increases were greater with sesame rich in lignans than with Maskin. Noticeably, peroxisomal activity levels were >3 times higher in rats fed diets containing sesame seeds from the 0730 and 0732 lines than in those fed a control diet without sesame. The diet containing Masekin seed caused only a 50% increase in the value, however. Diets containing seeds from the 0730 and 0732 lines, compared to the control and Masekin diets, also significantly increased the activity of hepatic fatty acid oxidation enzymes including acyl-CoA oxidase, carnitine palmitoyltranferase, 3-hydroxyacyl-CoA dehydrogenase, and 3-ketoacyl-CoA thiolase. In contrast, diets containing sesame lowered the activity of enzymes involved in fatty acid synthesis including fatty acid synthase, glucose-6-phosphate dehydrogenase, ATP-citrate lyase, and pyruvate kinase. No significant differences in enzyme activities were, however, seen among diets containing sesame from Masekin cultivar and lines 0730 and 0732. Serum triacylglycerol concentrations were lower in rats fed diets containing sesame from lines 0730 and 0732 than in those fed the control or Masekin diet. It is apparent that sesame rich in lignans more profoundly affects hepatic fatty acid oxidation and serum triacylglycerol levels. Therefore, consumption of sesame rich in lignans results in physiological activity to alter lipid metabolism in a potentially beneficial manner. 相似文献
14.
运用常规的植物生理抗旱性测定方法,对引种植物沙漠豆在不同土壤水分梯度下叶片中的可溶性糖、可溶性蛋白质、脯氨酸以及过氧化氢酶（CAT）活性,超氧化物歧化酶（SOD）活性和过氧化物酶（POD）3种保护酶等指标的变化进行研究。结果表明：1）脯氨酸含量随干旱胁迫程度的增强逐渐升高,可溶性蛋白质先降低后升高,二者之间存在相互补偿关系,可溶性糖含量呈现先升高再降低的变化趋势,表现出渗透调节物质对干旱的调节作用;2）3种保护酶活性在不同水分处理过程中变化不同,CAT活性表现为升高,SOD在中度干旱水分条件下升高,至重度干旱水分条件下则降低,POD活性的变化与SOD活性变化相反,保护酶之间相互配合协同作用维持了沙漠豆叶片细胞膜的完整性;3）丙二醛浓度随干旱胁迫程度的增强而升高,表明沙漠豆随水分不足可以通过增加渗透调节物质含量、增强保护酶活性、提高抗氧化能力,来减轻干旱胁迫的伤害。 相似文献
15.
S A Gaziola E S Alessi P E Guimaraes C Damerval R A Azevedo 《Journal of agricultural and food chemistry》1999,47(3):1268-1275
Quality protein maize (QPM) varieties have been produced by the introduction of opaque-2 modifier genes. Two QPM varieties, BR451 and BR473, a wild type and an opaque-2 variety, have been used to study key enzymes controlling lysine metabolism in the endosperm during development. Aspartate kinase and homoserine dehydrogenase enzymes, which are involved in lysine and threonine biosynthesis, respectively, exhibited identical activity patterns during endosperm development, with a maximum specific activity at 16 days after pollination. The QPM varieties exhibited higher levels of aspartate kinase activity in the endosperm, suggesting an increased rate of lysine biosynthesis when compared to the opaque-2 and wild-type genotypes. Similar results were observed for the lysine ketoglutarate reductase and saccharopine dehydrogenase enzymes, which form a single bifunctional polypetide involved in endosperm lysine degradation. Both enzyme activities were strongly reduced in the opaque-2 maize variety when compared to the wild-type maize, whereas the QPM varieties exhibited even lower levels of lysine ketoglutarate reductase-saccharopine dehydrogenase activities when compared to the opaque-2 variety. The developmental pattern of enzyme activity showed a different profile when compared to the enzymes involved in lysine biosynthesis, with activity being detected only 12-16 days after pollination (DAP) and maximum activities approximately 24 DAP. These results also suggest that the modifier genes have intensified the effect of the opaque-2 mutation on lysine ketoglutarate reductase-saccharopine dehydrogenase. These alterations lead to an increase in soluble lysine in the endosperm of the QPM varieties when compared to the opaque-2 and wild type. 相似文献
16.
试验采用蛭石-珍珠岩盆栽方式,研究了不同浓度氮(5、10、20 mmol/L,记作N1、N2、N3)、硫(2、4、8 mmol/L,记作S1、S2、S3)配施条件对大蒜鳞茎品质的影响,并采用隶属函数法对大蒜品质进行综合评价,分析鳞茎品质与氮硫互作水平的响应关系。试验结果表明,氮素、硫素对大蒜主要营养成分含量影响不尽相同,氮硫配施能够不同程度提高大蒜鳞茎中可溶性蛋白、VC、大蒜多糖、游离氨基酸的含量,且氮、硫单一因素对大蒜鳞茎品质影响远低于元素间交互作用。但在氮素适宜水平下(10~20 mmol/L),硫素水平对大蒜鳞茎中大蒜辣素含量有显著影响,提高硫浓度能够显著增加大蒜辣素含量,而在硫素浓度过高时(8 mmol/L)则明显抑制该物质合成。隶属函数法综合评价以N3S2处理组大蒜鳞茎品质最优,隶属函数值为0.81,对照组(CK)最差。综合分析可见,无机基质栽培条件下氮硫配施显著影响大蒜鳞茎品质,氮素浓度20 mmol/L(N3)、硫素浓度4 mmol/L(S2)时最利于大蒜鳞茎品质的提升,为大蒜无机基质栽培最佳氮、硫配施水平,且两元素配施存在明显的互作效应。该结论为大蒜栽培氮、硫元素合理配施提供试验指导。 相似文献
17.
Increasing oxidative stress is intimately involved in the pathogenesis of lung failure. Nuclear factor-erythroid 2 related factor 2 (Nrf2) is a key element in redox homeostasis. Nrf2 regulates antioxidant-associated genes that are often the target of phytochemicals in chemoprevention. This study evaluated the effect of diallyl sulfide (DAS), which is present in garlic, on the expression of antioxidant enzymes in the rat lung and the Nrf2 modulation in MRC-5 lung cells. DAS increased the activities of glutathione S-transferase, glutathione reductase, and catalase as well as the GSH/GSSG ratio compared with the lung of untreated control rats (p < 0.05). The pulmonic superoxide dismutase, glutathione peroxidase, NAD(P)H:quinone oxidoreductase 1, and catalase mRNA levels were also significantly increased (p < 0.05) after DAS treatment. Following DAS treatment, DAS level was measured in the plasma after 7 days of oral administration, and the C(max) value was 15 ± 4.2 μM. The total amount of pulmonic Nrf2 and the nuclear translocation of Nrf2 were elevated in DAS-treated rats, clarifying the effect of DAS on the modulation of antioxidant enzymes. Furthermore, DAS could induce nuclear translocation of Nrf2 via ERK/p38 signaling pathway in lung MRC-5 cells. This study demonstrates that DAS administration can significantly induce the activity of antioxidant enzymes in rat lungs and suggests a possible use for DAS as a dietary preventive agent against oxidative stress-induced lung injury. 相似文献
18.
D. J. ROSS 《European Journal of Soil Science》1966,17(1):1-15
Some climatic and soil factors influencing the activities of enzymes hydrolysing sucrose and starch in New Zealand soils under pasture were studied. Amounts of reducing sugars produced on incubation of soils without added substrate were related very closely to soil organic C content. Activities of (a) enzymes hydrolysing sucrose and (b) enzymes hydrolysing starch decreased and increased, respectively, with increasing rainfall; the ratios (a)/(i) were highest in the driest groups of soils. Variations in annual rainfall and soil organic C together, but not separately, explained much of the variation in sucrose-hydrolysing activities; these activities appeared to be related more to the composition than the amount of organic matter in a soil. Variations in activity of enzymes hydrolysing starch could be explained by variations in soil organic C, clay content, and, in some cases, other factors associated with different soil groups; these activities were increased by irrigation and reduced by drainage of soils. The activity of starch-hydrolysing enzymes, compared with sucrose-hydrolysing enzymes, was relatively greater under legumes than under grasses at the same site but could differ considerably at different sites. Activities also differed under forest and pasture at adjacent sites. 相似文献
19.
玉米/蒜苗套作系统中土壤微生物和土壤酶状况分析 总被引：7，自引：1，他引：7
对玉米蒜苗套作根区进行隔膜、隔网和无隔处理以及各自单作处理,通过处理间的相互比较,分析影响套作产量的主要土壤因素。结果表明:套作蒜苗土壤微生物上升其主要原因是根系间的非接触物质交换;套作玉米除此外,地上部环境的改变也使根部土壤微生物数量上升。根系间的非接触效应还使蒜苗、玉米土壤过氧化氢酶、蔗糖酶活性提高,而环境因素的改变也使玉米过氧化氢酶,蒜苗脲酶活性提高。相关性分析表明:微生物对蒜苗根际土壤酶活性的影响大于对玉米土壤酶的影响。 相似文献
20.
Hanlon N Okpara A Coldham N Sauer MJ Ioannides C 《Journal of agricultural and food chemistry》2008,56(17):7866-7871
Administration of dietary doses of the isothiocyanate erucin had no effect on rat hepatic cytochrome P450 activity or protein levels, but at higher doses a rise in CYP1A/B1 protein levels was evident. In lung, treatment with erucin, as well as sulforaphane, failed to modulate cytochrome P450 activities but elevated CYP1A/B1 protein levels. In liver, erucin stimulated quinone reductase activity accompanied by a rise in protein. Glutathione S-transferase activity was unaffected, but GSTalpha and GSTmu protein levels increased. In lung, both isothiocyanates increased quinone reductase paralleled by a rise in protein levels; at the higher dose both isothiocyanates elevated moderately GSTalpha levels. Hepatic microsomes converted both isothiocyanates to metabolites that impaired cytochrome P450 activity, which was antagonized by reduced glutathione. It may be concluded that erucin may protect against carcinogens by stimulating the detoxication of quinones but is unlikely to significantly influence reactive intermediate generation through modulation of cytochrome P450 activity. 相似文献