Diallyl disulfide and diallyl trisulfide up-regulate the expression of the pi class of glutathione S-transferase via an AP-1-dependent pathway

Garlic organosulfur compounds are recognized as potential chemopreventive compounds. This protection is related to the induction of phase II detoxification enzymes. We previously reported that diallyl disulfide (DADS) and diallyl trisulfide (DATS) up-regulate the gene expression of the pi class of glutathione S-transferase (GSTP) and that an enhancer element named GPE I is required for this induction. In the present study, we further investigated the signal pathway involved in DADS and DATS up-regulation of this detoxification enzyme in Clone 9 cells. Cells were cultured with 25-200 micromol/L of DADS or DATS for 24 h. Western and Northern blots showed that both garlic allyl sulfides concentration dependently induced GSTP protein and mRNA expression, respectively. Changes in GST activity toward ethacrynic acid were consistent with the increase in GSTP expression (P < 0.05). Electromobility gel shift assay showed that the DNA binding activity of nuclear activator protein-1 (AP-1) is concentration-dependently increased in the presence of DADS and DATS as compared with that of the control cells. The phosphorylation of c-Jun NH2-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK), but not of p38, was stimulated in the presence of both garlic allyl sulfides. Pretreatment with SP600125 and PD98059, which are JNK and ERK inhibitors, respectively, abolished the increase in AP-1-DNA binding activity and also the induction of GSTP protein by either allyl sulfide. Our results indicate that the effectiveness of DADS and DATS on GSTP expression is likely related to the JNK-AP-1 and ERK-AP-1 signaling pathways and, thus, that DADS and DATS enhance the binding of AP-1 to GPE I.     

Hydroxyl radical reactivity with diethylhydroxylamine

Diethylhydroxylamine (DEHA) reacts with gas-phase hydroxyl radicals on every third collision, whereas the corresponding reaction in aqueous solution is considerably slower. The high gas-phase reactivity explains the predicted inhibitory effect of DEHA in atmospheric smog processes. Results from the studies in the aqueous phase are helpful in predicting the mechanism of the reaction of DEHA with hydroxyl radicals.     

Suppressive effect of the ethanolic extract of adlay bran on cytochrome P-450 enzymes in rat liver and lungs

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.     

Effect of garlic oil on neutrophil infiltration in the small intestine of endotoxin-injected rats and its association with levels of soluble and cellular adhesion molecules

Garlic ( Allium sativum ) possesses anti-inflammatory effects. This study investigated the effects of garlic oil on endotoxin-induced neutrophil infiltration in the small intestine. Wistar rats received by gavage 10, 50, or 100 mg/kg body wt garlic oil (GO) or the vehicle (corn oil; 2 mL/kg body wt) every other day for 2 weeks before being injected with endotoxin (ip, 5 mg/kg body wt). Control rats were administered corn oil and injected with sterile saline. Blood samples for the measurement of soluble adhesion molecules were collected at various time points after injection, and all other samples were collected 18 h after injection. The 10 and 50 mg/kg doses suppressed endotoxin-induced neutrophilia, serum levels of sL-selectin and sICAM-1, cellular CD11b on neutrophils, intestinal ICAM-1 content, and neutrophil infiltration (P < 0.05). The 100 mg/kg dose significantly lowered local ICAM-1 and cellular CD11b on neutrophils (P < 0.05) but did not have a beneficial effect on neutrophil infiltration. In addition, 100 mg/kg of GO worsened the elevation of the local TNF-α level and neutrophilia. Appropriate doses of garlic oil have a preventive effect on endotoxin-induced neutrophil infiltration and damage to the small intestine.     

DATS reduces LPS-induced iNOS expression, NO production, oxidative stress, and NF-kappaB activation in RAW 264.7 macrophages

Diallyl trisulfide (DATS), diallyl sulfide (DAS), and diallyl disulfide (DADS) are the three major organosulfur compounds (OSCs) in garlic oil. In contrast to DADS and DATS, evidence of an anti-inflammatory effect of DATS is limited. In this study compares the efficacy of DATS with those of DAS and DADS on lipopolysaccharide (LPS)-induced inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) production in RAW 264.7 macrophages. The NO production in LPS-activated RAW 264.7 macrophages was suppressed by both DADS and DATS in a dose-dependent manner. At 100 muM, the nitrite levels of DADS- and DATS-treated cells were 57 and 34%, respectively, of cells treated with LPS alone. DAS, however, had no influence on NO production even at a concentration of 1 mM. Western blot and Northern blot assays showed that DADS and DATS but not DAS dose-dependently suppressed LPS-induced iNOS protein and mRNA expression in a pattern similar to that noted for NO production. LPS-induced cellular peroxide production was significantly inhibited by DADS and DATS (P < 0.05) but not by DAS. Electrophoresis mobility shift assays further indicated that DADS and DATS effectively inhibited the activation of NF-kappaB induced by LPS. Taken together, these results indicate that the differential efficacy of three major OSCs of garlic oil on suppression of iNOS expression and NO production is related to the number of sulfur atoms and is in the order DATS > DADS > DAS. The inhibitory effect of DATS on LPS-induced iNOS expression is likely attributed to its antioxidant potential to inhibit NF-kappaB activation.     

Changes in Retrogradation Properties of Rice Starches with Amylose Content and Molecular Properties

The increases in storage modulus (G′), retrogradation enthalpy change (ΔH) and ΔH‐related Avrami kinetic parameters of gelatinized rice starch dispersions at 25% (w/w) were investigated with respect to storage period, amylose content (AC), and molecular properties. Three high‐AC and five low‐AC rice cultivars were compared for understanding the multiple influences of AC and molecular properties involved. After refining the results of correlation analysis, the G′ of just‐cooled samples changed positively, mainly with AC and additionally with the average chain length of amylose (CL_AM) and the weight ratio of extra‐long plus long chains to short chains of amylopectin (AP) (r_APchain). The developed ΔH on short‐term storage (10 days) elevated with increasing AC and CL_AM and decreasing degree of polymerization of AP (DP_AP), but after long‐term aging for one to three months with increasing r_APchain, especially for the low‐AC cultivars examined. Greater Avrami rate constants for retrogradation could be attributed to the combination of a lower DP_AP and r_APchain or AP chain length and a greater CL_AM. The polynomials using these critical factors to describe the retrogradation parameters were elucidated and could account for 85–99.6% of data deviations.     

Effect of Nutrition Condition and Host Density on the Offspring of Asecodes hispinarum Bou(c)ek

椰甲截脉姬小蜂(Asecodes hispinarum Bou(c)ek)是椰心叶甲[Brontispa longissima (Gestro)]害虫的重要内寄生蜂,主要寄生害虫的4龄幼虫.为了更好地为室内繁殖寄生蜂提供理论依据,开展了营养条件和寄主密度的改变对椰甲截脉姬小蜂子代的影响.结果表明:(1)补充10％蜂蜜水作为营养的情况下,椰甲截脉姬小蜂寄生能力随寄主密度不同存在差异.每对寄生蜂在寄主数量为5时,被寄生的椰心叶甲数量最多,为2.33头.当寄主密度大于5时,椰心叶甲被寄生的数量有随寄主密度增加而降低的趋势;不补充营养时,寄生蜂的寄生能力差异不显著.(2)补充10％蜂蜜水时,寄主密度对每寄主出蜂量、椰甲截脉姬小蜂羽化率和后代性比并无显著影响.(3)不补充营养时,寄主密度对每寄主出蜂量和椰甲截脉姬小蜂后代性比均有显著影响,对椰甲截脉姬小蜂羽化率无影响,每寄主出蜂数量最多为45.67头,后代性比最高为96.66％.     

Garlic allyl sulfides display differential modulation of rat cytochrome P450 2B1 and the placental form glutathione S-transferase in various organs

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.     

Effects of Modulated Differential Scanning Calorimetry (MDSC) Variables on Thermodynamic and Kinetic Characteristics During Gelatinization of Waxy Rice Starch

The total, reversing, and nonreversing thermal properties during gelatinization of waxy rice starch (starch-to-water ratio = 1:2, w/w) were examined by modulated differential scanning calorimetry (MDSC). The effect of MDSC operating variables (i.e., the amplitude and frequency of temperature modulation and the underlying heating rate) on these thermal properties was determined by response surface methodology (RSM) and statistical analysis. The frequency of temperature modulation and the underlying heating rate significantly influenced the gelatinization temperatures and enthalpy changes in total and nonreversing endotherms. In addition, the combination of 0.025Hz and 4–8°C/min with a properly low degree of oscillation was suitable for characterization of starch gelatinization by MDSC. The enthalpy changes in the reversing (thermodynamic) endotherms increased, but those in the nonreversing (kinetic) endotherms decreased with increasing periods (i.e., decreasing frequencies) and underlying heating rates. However, the total enthalpy changes were only slightly influenced by the MDSC variables studied. In addition, the activation energies for the total and nonreversing events were 281.8–417.3 and 386.3–739.7 kJ/mol, respectively, depending on the MDSC conditions. From the compensation relationship between the activation energy and frequency factor, we concluded that the total and nonreversing endotherms were linked to the same single transition.     

Effects of Milling on the Physicochemical Characteristics of Waxy Rice in Taiwan

Three types of mills and six milling methods were employed to mill two waxy rice varieties (TCSW1, long grain; TCW70, short grain), and the physicochemical and functional properties of rice flour were examined. The results showed that dry-milling maintained a higher level of the chemical components than other milling methods. Wet-milling slightly increased solubility as test temperatures increased, and significantly increased swelling power at 75 and 85°C for TCSW1 and TCW70, respectively. Hammer and semi-dry hammer milling gave higher percentages of coarse particles (100–300 μm); cyclone and turbo milling led to a more even particle-size distribution, and the wet-milling gave the finest particles (10–30 μm). Dry hammer-milled rice had higher gelatinization and pasting temperatures, and semi-dry grinding milling resulted in the lowest pasting temperature, setback viscosity, and enthalpy value among the mills. The final quality of the two waxy rice varieties was profoundly affected by the mill type and milling method.