Modulatory influence of Adhatoda vesica (Justicia adhatoda) leaf extract on the enzymes of xenobiotic metabolism,antioxidant status and lipid peroxidation in mice

The effect of two different doses (50 and 100 mg/kg body wt/day for 14 days) of 80% ethanolic extract of the leaves of Adhatoda vesica were examined on drug metabolizing phase I and phase II enzymes, antioxidant enzymes, glutathione content, lactate dehydrogenase and lipid peroxidation in the liver of 8 weeks old Swiss albino mice. The modulatory effect of the extract was also examined on extra-hepatic organs viz. lung, kidney and forestomach for the activities of glutathione S-transferase, DT-diaphorase, superoxide dismutase and catalase. Significant increase in the activities of acid soluble sulfhydryl (-SH) content, cytochrome P450, NADPH-cytochrome P450 reductase, cytochrome b₅, NADH-cytochrome b₅ reductase, glutathione S-transferase (GST), DT-diaphorase (DTD), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) were observed in the liver at both dose levels of treatments. Adhatoda vesica acted as bifunctional inducer since it induced both phase I and phase II enzyme systems. Both the treated groups showed significant decrease in malondialdehyde (MDA) formation in liver, suggesting its role in protection against prooxidant induced membrane damage. The cytosolic protein was significantly inhibited at both the dose levels of treatment indicating the possibility of its involvement in the inhibition of protein synthesis. BHA has significantly induced the activities of GR and GSH in the present study. The extract was effective in inducing GST and DTD in lung and forestomach, and SOD and CAT in kidney. Thus, besides liver, other organs viz., lung, kidney and forestomach were also stimulated by Adhatoda, to increase the potential of the machinery associated with the detoxification of xenobiotic compounds. But, liver and lung showed a more consistent induction. Since the study of induction of the phase I and phase II enzymes is considered to be a reliable marker for evaluating the chemopreventive efficacy of a particular compound, these findings are suggestive of the possible chemopreventive role played by Adhatoda leaf extract.     

Modulatory effect of Urtica dioica L. (Urticaceae) leaf extract on biotransformation enzyme systems, antioxidant enzymes, lactate dehydrogenase and lipid peroxidation in mice.

The effects of two doses (50 and 100 mg/kg body wt given orally for 14 days) of an ethanol-water (80%-20%) extract of Urtica dioica L. and butylated hydroxyanisole (BHA) were investigated, for phase I and phase II enzymes, antioxidant enzymes, lactate dehydrogenase, lipid peroxidation and sulfhydryl groups in the liver of Swiss albino mice (8-9 weeks old). A modulatory effect of two doses and BHA was also observed for the activities of glutathione S-transferase, DT-diaphorase, superoxide dismutase and catalase in the kidney, lung and forestomach, as compared with the control group. The activities of cytochrome b5 (cyt b5), NADH-cytochrome b5 reductase (cyt b5 R), glutathione S-transferase (GST), DT-diaphorase (DTD), glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD) and catalase (CAT) showed a significant increase in the liver at both dose levels of extract. Both extract-treated showed significantly lower activity of cytochrome P450 (cyt P450), lactate dehydrogenase (LDH), NADPH-cytochrome P450 reductase (cyt P450 R), total sulfhydryl groups (T-SH), nonprotein sulfhydryl groups (NP-SH) and protein-bound sulfhydryl groups (PB-SH). BHA-treated Swiss albino mice showed a notable increase in levels of cyt b5, DTD, T-SH, PB-SH, GPx, GR, and SOD in the liver while, LDH, cyt P450, cyt P450 R, Cyt b5 R, GST, NP-SH, and CAT levels were reduced significantly as compared to control values. The extract was effective in inducing GST, DTD, SOD and CAT activity in the forestomach and SOD and CAT activity in the lung at both dose levels. BHA-treated Swiss albino mice induced DTD, GST and all antioxidative parameters in the kidney, lung and forestomach.     

Chemomodulatory action of Aloe vera on the profiles of enzymes associated with carcinogen metabolism and antioxidant status regulation in mice.

The effect of two doses (30 microl and 60 microl/day/mice daily for 14 days) of the fresh leaf pulp extract of Aloe vera was examined on carcinogen-metabolizing phase-I and phase-II enzymes, antioxidant enzymes, glutathione content, lactate dehydrogenase and lipid peroxidation in the liver of mice. The modulatory effect of the pulp extract was also examined on extrahepatic organs (lung, kidney and forestomach) for the activities of glutathione S-transferase, DT-diophorase, superoxide dismutase and catalase. The positive control mice were treated with butylated hydroxyanisole (BHA). Significant increases in the levels of acid soluble sulfhydryl (-SH) content, NADPH-cytochrome P450 reductase, NADH-cytochrome b5 reductase, glutathione S-transferase (GST), DT-diaphorase (DTD), superoxide dismutase (SOD), catalase, glutathione peroxidase (GPX) and glutathione reductase (GR) were observed in the liver. Aloe vera significantly reduced the levels of cytochrome P450 and cytochrome b5. Thus, Aloe vera is clearly an inducer of phase-II enzyme system. Treatment with both doses of Aloe caused a decrease in malondialdehyde (MDA) formation and the activity of lactate dehydrogenase in the liver, suggesting its role in protection against prooxidant-induced membrane and cellular damage. The microsomal and cytosolic protein was significantly enhanced by Aloe vera, indicating the possibility of its involvement in the induction of protein synthesis. BHA, an antioxidant compound, provided the authenticity of our assay protocol and response of animals against modulator. The pulp extract was effective in inducing GST, DTD, SOD and catalase as measured in extrahepatic organs. Thus, besides liver, other organs (lung, kidney and forestomach) were also influenced favorably by Aloe vera in order to detoxify reactive metabolites, including chemical carcinogens and drugs.     

Modulatory influence of Brassica compestris Linn var sarson on phase-II carcinogen metabolizing enzymes and glutathione levels in mice

The present study reports the modulatory influence of 95% ethanolic extract from the seeds of B. compestris on the activity of phase-II enzymes such as glutathione S-transferase (GST), DT-diaphorase (DTD) and reduced glutathione (GSH) level in the skin, lung, kidney and forestomach of the mouse. Oral treatment with the seed extract at 800 mg/kg body wt. for 15 days significantly elevated GST in lung and forestomach and DT-diaphorase in forestomach and skin and GSH level in lung, kidney forestomach and skin. The lower dose 400 mg/kg body wt was effective only in inducing GST and DT-diaphorase activity in forestomach and reduced glutathione level in lung. The findings suggest that B. compestris seed extract may block or suppress the events associated with chemical carcinogenesis at least in part, by inducing metabolic detoxification of the carcinogen.     

Lead-induced lipid peroxidation and antioxidant defense components of developing chick embryos.

Administration of lead (1.25 and 2.5 mumol/kg egg weight) to 14-day-old chick embryos enhanced the level of lipid peroxides (LPO) in tissues of liver, brain, and heart. Accumulation of LPO was maximum at 9 h after treatment with lead and returned to normal level by 72 h. Further, we have studied the levels of glutathione-S-transferase (GST), glutathione reductase (GR), glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase. At 9 h posttreatment, the hepatic GR was reduced significantly with the induction of GST and considerable depletion of GSH. However, in brain and heart, both GR and GST activities were unaltered with significant reduction of GSH. Further, an increase of non-Se-dependent GPx and SOD activities were observed in liver, brain, and heart. Similarly, at 72 h, although the GPx activity was found decreased in liver and brain, the GST, catalase, and SOD activities were significantly increased in all the three tissues alike, suggesting tissue-specific changes of antioxidant defense components in response to lead treatment. Our results suggests that the elevated levels of GST, SOD, and catalase at 72 h were successful in bringing LPO levels back to normal.     

Modulation of Glutathione and Glutathione Dependent Antioxidant Enzymes in Mouse Heart Following Doxorubicin Therapy

The toxicity of the antineoplastic agent doxorubicin (DOX) has been shown to be moderated by the antioxidant enzyme glutathione peroxidase. It has been reported that acute doses of DOX can cause an inhibition of glutathione peroxidase in cardiac tissue, that may render this tissue especially susceptible to further prooxidant damage. In this study, multiple DOX treatments at a therapeutic dose were assessed for their effect on the antioxidant enzyme status of cardiac and kidney tissue. DOX was administered i.p. (5 mg/kg) once a week for two weeks to male balb/c mice. The activities of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPOX) and glutathione reductase (GR) were measured 1, 2 and 7 days following the second DOX treatment in both heart and kidney. Levels of reduced glutathione (GSH) were also measured in cardiac tissue at these same times. Cardiac levels of GPOX and GR showed a time-dependent decrease in activity, with 10% and 12% inhibition for GPOX and GR, respectively, at 7 days post second treatment. Cardiac levels of GSH also showed a significant decrease, approximately 15%, at 7 days post second treatment. Cardiac levels of SOD and CAT as well as kidney levels of all four antioxidant enzymes were not affected by DOX treatment. These data suggest that DOX given in a therapeutic regimen, at a therapeutic dose, can cause decreases in cardiac levels of GPOX, GR and GSH that could render the heart especially susceptible to further oxidative challenge.     

Antioxidant Enzymatic System in Neuronal and Glial Cells Enriched Fractions of Rat Brain After Aluminum Exposure

The aim of this work was to investigate as to how neurons and glial cells separated from the brain cortex respond to oxidative stress induced by aluminum. Female SD rats were exposed to aluminum at the dose level of 100 mg/kg b.w. for 8 weeks. Neuronal and glial cell-enriched fractions were obtained from rat cerebral cortex by sieving the trypsinated homogenate through a series of nylon meshes, followed by centrifugation on ficoll density gradient. Total glutathione content, glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione-s-transferase (GST) along with antioxidant enzymes superoxide dismutase (SOD), catalase were estimated in neuronal and glial-enriched fractions in both control (N-c and G-c) and aluminum exposed animals (N-a and G-a). Secondary products of lipid peroxidation that is MDA levels were estimated by measuring the (TBARS) levels. Our results indicate that TBARS levels were significantly higher in glial cell fraction of unexposed controls (Gc) than the neuronal cells (Nc). Correspondingly the glial cells had higher levels of GSH, GSSG, GPx and GST where as neurons had higher levels of catalase, SOD and GR. Following aluminum exposures significant increase in the TBARS levels was observed in neurons as compared to glial cells which also showed a significant decrease in SOD and catalase activity. The decrease in the TBARS levels in the glial cells could be related to the increase in the GSH levels, GR activity, and GST activity which were found to be increased in glial enriched fractions following aluminum exposure. The increase in activity of various enzymes viz GR, GST in glial cells as compared to neurons suggests that glial cells are actively involved in glutathione homeostasis. Our conclusion is that glial and neurons isolated from rat cerebral cortex show a varied pattern of important antioxidant enzymes and glial cells are more capable of handling the oxidative stress conditions.     

Melatonin reduces oxidative stress induced by ochratoxin A in rat liver and kidney

Melatonin (MEL) displays antioxidant and free radical scavenger properties. In the present study, the effect of MEL on the oxidative stress induced by ochratoxin A (OTA) administration in rats was investigated. Four groups of 15 rats each were used: controls, MEL-treated rats (5 mg/kg body mass), OTA-treated rats (250 μg/kg) and MEL+OTA-treated rats. After 4 weeks of treatment, the levels of malondialdehyde (MDA), a lipid peroxidation product (LPO) were measured in serum and homogenates of liver and kidney. Also, the levels of glutathione (GSH), and activities of glutathione reductase (GR), glutathione peroxidase (GSPx), superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST) in liver and kidney were determined. In OTA-treated rats, the levels of LPO in serum and in both liver and kidney were significantly increased compared to levels in controls. Concomitantly, the levels of GSH and enzyme activities of SOD, CAT, GSPx and GR in both liver and kidney were significantly decreased in comparison with controls. In rats received MEL+OTA, the changes in the levels of LPO in serum and in liver and kidney were not statistically significant compared to controls. Concomitantly, the levels of GSPx, GR and GST activities in both liver and kidney tissues were significantly increased in comparison with controls. Similar increases in GSPx, GR and GST activities were also observed in MEL-treated rats when compared with controls. In conclusion, the oxidative stress may be a major mechanism for the toxicity of OTA. MEL has a protective effect against OTA toxicity through an inhibition of the oxidative damage and stimulation of GST activities. Thus, clinical application of melatonin as therapy should be considered in cases of ochratoxicosis.     

Chemopreventive potential of luteolin during colon carcinogenesis induced by 1,2-dimethylhydrazine

We investigated the chemopreventive potential of luteolin on hepatic and circulatory lipid peroxidation and antioxidant status during 1,2-dimethylhydrazine induced colon carcinogenesis in rats. Rats were given a weekly subcutaneous injection of DMH at a dose of 20 mg/kg body weight for 15 weeks. Luteolin (0.2 mg/kg body weight/everyday p.o.) was given at the initiation and also at the postinitiation stages of carcinogenesis to DMH treated rats. The animals were sacrificed at the end of 30 weeks. Enhanced lipid peroxidation in the liver and circulation of tumor bearing rats was accompanied by a significant decrease in the levels of plasma and hepatic reduced glutathione (GSH), glutathione peroxidase (GPx), glutathione-S-transferase (GST), glutathione reductase (GR), superoxide dismutase (SOD), catalase (CAT), vitamin C, vitamin E and beta-carotene in DMH treated rats as compared to the control rats. Intragastric administration of luteolin (0.2mg/kg body weight) to DMH-treated rats significantly reduced the incidence and size of tumor in the colon, reduced lipid peroxidation levels and enhanced the plasma and hepatic activities of GSH, GPx, GST, GR, SOD, CAT, vitamin C, vitamin E and beta-carotene. Thus the chemopreventive efficacy of luteolin against colon carcinogenesis is evidenced by our preliminary studies which showed decreased incidence of tumors and the antiperoxidative and antioxidant effect of luteolin. Further study on the exact mechanism of action of luteolin in preventing colon carcinogenesis is yet to be elucidated.     

Antioxidative and metabolic responses to extended cold exposure in rats

In this work, we investigated whether extended cold exposure increases oxidative damage and susceptibility to oxidants of rat liver, heart, kidney and lung which are metabolically active tissues. Moreover in this study the effect of cold stress on some of the lipid metabolic mediators were studied in rat experimental model. Male albino Sprague-Dawley rats were randomly divided into two groups: The control group (n=12) and the cold-stress group (n=12). Tissue superoxide dismutase (SOD), catalase (CAT), glutathion S-transferase (GST) and glutathion reductase (GR) activities and glutathion (GSH) were measured using standard protocols. The biochemical analyses for total lipid, cholesterol, trigliceride, HDL, VLDL and LDL were done on autoanalyzer. In cold-stress groups SOD activity was decreased in the lung whereas it increased in the heart and kidney. CAT activity was significantly decreased (except liver) in all the tissues in treated rats. GST activity of cold-induced rats increased in liver and heart while decreased in the lung. GR activity was significantly decreased (except in liver) in all the tissues in cold-stressed rats. GSH level was significantly increased in the heart but decreased in the lung of animals exposed to cold when compared to controls. It was found that among the groups trigliceride, total lipid, HDL and VLDL parameters varied significantly but cholesterol and LDL had no significant variance. In this study, we found that exposure of extended (48 h) cold (8 degrees C) caused changes both in the antioxidant defense system (as tissue and enzyme specific) and serum lipoprotein profiles in rats.     

光质对烟草叶片生长发育过程中抗氧化系统的影响

以云烟87植株为材料,通过覆盖白、红、黄、蓝、紫色滤膜获得不同光质,于大田条件下研究了光质对烟草叶片生长发育过程中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)、谷胱甘肽过氧化物酶(GPX)、谷胱甘肽还原酶(GR)等抗氧化酶活性,抗氧化剂谷胱甘肽(GSH)和抗坏血酸(AsA)以及丙二醛(MDA)含量的影响.结果表明,在烟草植株第11片叶生长发育的7~70 d内,其抗氧化酶活性和抗氧化物质含量呈现先升高后下降的变化趋势.与白光(对照)相比,黄光诱导烟草叶片SOD、CAT、APX和GR活性升高,以及AsA和GSH含量增加;而红光诱导APX和GR活性上升,以及GSH和AsA含量升高;但紫光却使SOD、CAT、POD、GR和GPX活性下降,GSH和AsA含量降低,而蓝光则使所有抗氧化酶活性和抗氧化物质含量降低.紫光和蓝光处理的烟草叶片中MDA含量较高,而黄光和红光处理的则较低.总体而言,在大田条件下,相对红光和黄光而言,蓝光和紫光处理下的烟草叶片更容易发生光氧化胁迫.     

Evaluation of gender-related differences in various oxidative stress enzymes in mice

Oxidative stress caused by redundant free radical, lipid oxygen and peroxide usually results in the pathogenesis of various diseases, which can be alleviated by cellular antioxidant enzymes. According to statistics, there are different incidence rates of some diseases depending on the gender. The present study aimed to investigate potential gender-related differences of antioxidant enzymes in mice. The activities of glutamate-cysteine ligase (GCL), glutathione reductase (GR), glutathione peroxidase (GPx), glutathione S-transferase (GST), superoxide dismutase (SOD) and catalase (CAT) in the kidney, brain, lung and heart of both male and female mice were determined. Our results showed that GPx and GCL activities were higher in female kidney and brain than those in male. On the other hand, the activities of SOD were higher in female brain and lung than those in male. Moreover, female kidney appeared to show higher activities of CAT than the male kidney. But the activities of GCL and GPx were higher in male heart than those in female. Taken together, our results demonstrate that there are gender-related differences in the activities of cellular antioxidant enzymes in various important organs in mice. Variations in such enzymes may be the explanation for some gender-related diseases.     

Effects of water extract of Usnea longissima on antioxidant enzyme activity and mucosal damage caused by indomethacin in rats

In this study, the antiulcerogenic effect of a water extract obtained from the lichen species Usnea longissima was investigated using indomethacin-induced ulcer models in rats. Experimental groups consisted of six rats. Antiulcerogenic activities of 50, 100 and 200mg/kg body wt. doses of the water extract were determined by comparing the negative (treated only with indomethacin) and positive (ranitidine) control groups. Although all doses of the water extract of U. longissima showed significant antiulcerogenic activity as compared to negative control groups, the highest activity was observed with 100 mg/kg body wt. doses (79.8%). The water extract of U. longissima showed moderate antioxidant activity when compared with trolox and ascorbic acids used as positive antioxidants. In addition, the activities of antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST)] were determined in the stomach tissues of rats and compared with those of the negative and positive control groups to expose the effects of antioxidant enzymes on antiulcerogenic activity. SOD and GST enzymes activities in indomethacin-administrated tissues were reduced significantly by indomethacin in comparison to control groups. These enzymes were activated, however, by the water extracts of U. longissima. In contrast to SOD and GST activities, CAT activity was increased by indomethacin and reduced by all doses of U. longissima and ranitidine. The present results indicate that the water extract of U. longissima has a protective effect in indomethacin-induced ulcers, which can be attributed to its antioxidant potential.     

Effect of salinity and different nitrogen sources on the activity of antioxidant enzymes and indole alkaloid content in Catharanthus roseus seedlings

The activities of antioxidant enzymes viz. glutathione reductase, GR; superoxide dismutase, SOD; peroxidase, POD; catalase, CAT and glutathione-S-transferase, GST and alkaloid accumulation were investigated in leaf pairs (apical, middle, basal) and in roots of Catharanthus roseus seedlings under the conditions of different nitrogen sources (20 mM KNO(3) and 2 mM NH(4)Cl) and salinity, in the absence (non-saline control) and in the presence of 100 mM NaCl in the nutrient solution. Salinity caused a reduction in plant biomass. The biomass production of ammonium-fed plants was lower than that of nitrate-fed plants. The antioxidant enzymes exhibited higher activity in saline-treated plants. Changes in antioxidant enzyme activity caused by different nitrogen sources differed in all leaf pairs, as well as in roots of C. roseus. Ammonium-fed plants showed higher CAT, GR and GST activity in leaf pairs as well as in roots, while POD and SOD activity were higher in nitrate-fed plants. Higher peroxidase activity concomitant with the increased accumulation of alkaloid was found in all leaf pairs, as well as in roots of C. roseus of NO(3)(-) fed plants as compared to NH(4)(+) fed plants.     

Temperature increase results in oxidative stress in goldfish tissues. 2. Antioxidant and associated enzymes

Activities of superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), glutathione-S-transferase (GST), glutathione reductase (GR), and glucose-6-phophate dehydrogenase (G6PDH) were measured in four tissues of goldfish, Carassius auratus L., over 1-12 h of high temperature (35 degrees C) exposure followed by 4 or 24 h of lower temperature (21 degrees C) recovery. SOD activity was strongly affected by heat shock, increasing 4-fold in brain, liver, and kidney, but was mainly reversed at recovery. In some tissues, activities of SOD, catalase, GPx, and G6PDH decreased significantly after 1 h heat shock exposure suggesting that thermal inactivation possibly occurred, but were renewed at further exposure. In many cases, 4 h of return to the initial temperature decreased enzyme activities. High correlation coefficients between SOD activities and levels of lipid peroxidation products suggest that these products might be involved in up-regulation of antioxidant defense. Several enzymes (SOD, GST, GR) responded to stress in coordinated manner.     

镉对长江华溪蟹肝胰腺抗氧化酶活力的影响

重金属对环境的污染已成为全球面临的首要问题之一,其中镉(Cd2 )是一种广泛存在的毒性污染物,能通过消化道和呼吸道进入生物体,对机体造成损伤(Zyadah and Abdel-Baky,2000)。研究表明,Cd2 可以通过Ca2 通道穿过细胞膜进入机体(Roesijadi and Robinson,1994),诱导产生大量自由基和活性氧(ROS),从而形成氧胁迫(Toppi andGabbrielli,1994;Hegedus et al.,2001)。ROS可以与体内脂质、蛋白质和核酸反应,导致脂质过氧化、细胞膜损伤并且影响多种酶的活力,对生物体造成威胁。由于在水生生态系统中生物富集污染物的作用明显,故相对于陆地生…     

Chemomodulatory efficacy of basil leaf (Ocimum basilicum) on drug metabolizing and antioxidant enzymes, and on carcinogen-induced skin and forestomach papillomagenesis.

Basil or sweet basil (Ocimum basilicum) is cultivated throughout India and is known for its medicinal value. The effects of doses of 200 and 400 mg/kg body weight of hydroalcoholic extract (80% ethanol, 20% water) of the fresh leaves of Ocimum basilicum on xenobiotic metabolizing Phase I and Phase II enzymes, antioxidant enzymes, Glutathione content, Lactate dehydrogenase and lipid peroxidation in the liver of 8-9 weeks old Swiss albino mice were examined. Furthermore, the anticarcinogenic potential of basil leaf extract was studied, using the model of Benzo(a)pyrene-induced forestomach and 7,12 dimethyl benz(a)anthracene (DMBA)-initiated skin papillomagenesis. The hepatic glutathione S-transferase and DT-diaphorase specific activities were elevated above basal level by basil leaf treatment (from p < 0.005 to p < 0.001). Basil leaf extract was very effective in elevating antioxidant enzyme response by increasing significantly the hepatic glutathione reductase (GR) (p < 0.005), superoxide dismutase (SOD) (p < 0.05), and catalase activities (p < 0.005). Reduced glutathione (GSH), the major intracellular antioxidant, showed a significant elevation in the liver (p < 0.005) and also in all the extrahepatic organs (from p < 0.05 to p < 0.005). In the forestomach, kidney and lung, glutathione S-transferase and DT-diaphorase levels were augmented significantly, varying from p < 0.01 to p < 0.001. There were significant decreases in lipid peroxidation and lactate dehydrogenase activity. Chemopreventive response was evident from the reduced tumor burden (the average number of papillomas/mouse, p < 0.005 to p < 0.001), as well as from the reduced percentage of tumor bearing-animals. Basil leaf, as deduced from the results, augmented mainly the Phase II enzyme activity that is associated with detoxification of xenobiotics, while inhibiting the Phase I enzyme activity. There was an induction in antioxidant level that correlates with the significant reduction of lipid peroxidation and lactate dehydrogenase formation. Moreover, Basil leaf extract was highly effective in inhibiting carcinogen-induced tumor incidence in both the tumor models at peri-initiational level.     

Modulatory effect of Henna leaf (Lawsonia inermis) on drug metabolising phase I and phase II enzymes,antioxidant enzymes,lipid peroxidation and chemically induced skin and forestomach papillomagenesis in mice

Henna leaf (Lawsonia inermis), commonly known as Mehndi is cultivated throughout India and is a very popular natural dye to color hand and hair. It is an integral part of indigenous culture, and is also known for its medicinal value. The effect of 200 and 400 mg/kg body weight of 80% ethanolic extract of the fresh leaves of Lawsonia inermis were examined on drug metabolizing phase-I and phase-II enzymes, antioxidant enzymes, glutathione content, lactate dehydrogenase and lipid peroxidation in the liver of 7 weeks old Swiss albino mice. Also anticarcinogenic potential of Henna leaf extract was studied adopting the protocol of benzo(a)pyrene induced forestomach and 7,12 dimethylbenz(a)anthracene (DMBA)-initiated and croton oil-promoted skin papillomagenesis. Our primary findings reveal the duel-acting nature of henna leaf as deduced from its potential to induce only the phase-II enzyme activity, associated mainly with carcinogen detoxification in liver of mice and inhibit the phase I enzyme activities. The hepatic glutathione S-transferase and DT-diaphorase specific activities were elevated above basal (p < 0.005) level by Lawsonia inermis extract treatment. With reference to antioxidant enzymes the investigated doses were effective in increasing the hepatic glutathione reductase (GR), superoxide dismutase (SOD) and catalase activities significantly (from p < 0.05 to p < 0.005) at both the dose levels. Reduced glutathione (GSH) measured as non-protein sulphydryl was found to be significantly elevated in liver (p < 0.005) and in all the extrahepatic organs studied (from p < 0.05 to p < 0.005). Among the extrahepatic organs examined (forestomach, kidney and lung) glutathione S-transferase and DT-diaphorase level were increased in a dose independent manner (from p < 0.05 to p < 0.005). Chemopreventive response was measured by the average number of papillomas per mouse (tumor burden) as well as percentage of tumor bearing animals and tumor multiplicity. There was a significant inhibition of tumor burden in both the tumor model systems studied (from p < 0.01 to p < 0.001). Tumor incidence was also reduced by both the doses used in our experiment in both the model systems.     

Evalution of toxicity of abcisic acid and gibberellic acid in rats: 50 days drinking water study

In the present study, the influence of subchronic effects of two plant growth regulators (PGRs) [Abcisic acid (ABA) and Gibberellic acid (GA₃)] on antioxidant defense systems [reduced glutathione (GSH), glutathione reductase (GR), superoxide dismutase (SOD), glutathione-S-transferase (GST) and catalase (CAT)] and lipid peroxidation level (malondialdehyde = MDA) in various tissues of the rat were investigated during treatment as a drinking water model. 75 ppm of ABA and GA₃ in drinking water were continuously administered orally to rats (Sprague-Dawley albino) ad libitum for 50 days. The PGRs treatments caused different effects on the antioxidant defense systems and MDA content of dosed rats compared to controls. The lipid peroxidation end product MDA significantly increased in the lungs, heart and kidney of rats treated with GA₃ without significant change in the spleen. ABA caused also a significant increase in MDA content in the spleen, lungs, heart and kidney. The GSH levels were significantly depleted in the spleen, lungs and stomach of rats treated with ABA without any change in the tissues of rats treated with GA₃ except the kidney where it increased. Antioxidant enzyme activities such as SOD significantly increased in the lungs and stomach and decreased in the spleen and heart tissues of rats treated with GA₃. Meanwhile, SOD significantly decreased in the spleen, heart and kidney and increased in the lungs of rats treated with ABA. While CAT activity significantly decreased in the lungs of rats treated with GA₃, a significant increase occurred in the heart of rats treated with both PGRs. On the other hand, the ancillary enzyme GR activity in the tissues were either significantly depleted or not changed with PGRs treatment. The drug metabolizing enzyme GST activity significantly decreased in the lungs of rats treated with ABA but increased in the stomach of rats treated with both PGRs.

As a conclusion, the rats resisted oxidative stress via the antioxidant mechanism. But the antioxidant mechanism could not prevent the increases in lipid peroxidation in rat's tissues. This data, along with changes, suggests that PGRs produced substantial systemic organ toxicity in the spleen, lungs, stomach, heart and kidney during a 50-day period of subchronic exposure.     

The protective effect of melatonin against cypermethrin-induced oxidative stress damage in Spodoptera litura (Lepidoptera: Noctuidae)

Antioxidant enzymes form the first-line defense against free radicals damage in organisms. Their regulation depends mainly on the oxidant and antioxidant status of the cell, given that oxidants are their principal modulators. Therefore, the aim of the present study was to investigate the effect of melatonin on synthetic pyrethroid insecticide-induced antioxidative enzymes activity in Spodoptera litura larvae. In addition, activities of enzymatic antioxidants viz. superoxide dismutase (SOD), glutathione S-transferase (GST), catalase (CAT), glutathione reductase (GR), α, β-esterase, and acetylcholine esterase (AChE) were assessed. There was no significant change in GST levels in the melatonin-treated groups. Melatonin modulates cypermethrin-induced changes in the activities of esterase and AChE, whereas SOD, CAT, and GR activity was significantly increased in melatonin-treated samples when compared to control. In conclusion, the results of the current study revealed that SP toxicity activated oxidant systems in all antioxidant systems in some tissues of insects. Melatonin administration led to a marked increase in antioxidant activity and inhibited GST and AChE in most of the tissues studied.