A phase II detoxification enzyme inducer from lemongrass: identification of citral and involvement of electrophilic reaction in the enzyme induction

We have developed a simple system for the sensitive detection and measurement of glutathione S-transferase (GST) activity that detoxifies polycyclic aromatic hydrocarbons using the cultured rat normal liver epithelial cell line, RL34 cells. Citral (3,7-dimethyl-2,6-octadienal) was isolated from the methanol extract of lemongrass (Cymbopogon citratus) and identified as a novel inducer of GST. Citral, a mixture of the two stereoisomers geranial and neral, dose- and time-dependently induced the total and pi-class-specific activities of GST. The structure-activity relationship study revealed that geranial, an E-isomer, was mainly responsible for the inducing activity of citral mixture and the aldehyde group conjugated with a trans-double bond is an essential structural factor. The data were consistent with the in vitro observation that both glutathione (GSH) and protein thiol quickly and specifically reacted with the active isomer geranial, but not neral. Pretreatment of the cells with diethyl maleate significantly enhanced not only the basal activity but also the citral-stimulated activity of GST, while pretreatment with N-acetyl-cysteine inhibited it. Moreover, the treatment of RL 34 cells with geranial for 30 min significantly attenuated the intracellular GSH level, while application for 18 h enhanced it. These results strongly suggested that the electrophilic property characterized by the reactivity with intracellular nucleophiles including protein thiol or glutathione (GSH) plays an important role in the induction of GST. The present study also implied the antioxidant role of GST induction by citral in mouse skin, providing a new insight into skin cancer prevention.     

Structure and expression of glutathione S-transferase genes from the midgut of the Common cutworm, Spodoptera litura (Noctuidae) and their response to xenobiotic compounds and bacteria

Glutathione S-transferases (GSTs) play a pivotal role in detoxifying endogenous and xenobiotic compounds and oxidative stress resistance in cells. In this study, five GST genes, including three Sigma GSTs (SlGSTs1, SlGSTs2, and SlGSTs3), one Omega GST (SlGSTo1) and one un-classified GST (SlGSTu1) were identified from the midgut of the Common cutworm, Spodoptera litura. Structure analyses of the eight (including the previously identified Epsilon GST genes, SlGSTe1, SlGSTe2 and SlGSTe3 from the same insect) SlGSTs genes showed that the Epsilon SlGSTe genes do not contain any intron, while the Sigma SlGSTs contain three introns and the Omega SlGSTo1 and the un-classified SlGSTu1 contain five introns. Analysis of the spatial and temporal expression of these eight SlGSTs indicated that SlGSTe1, SlGSTs2 and SlGSTo1 expressed in all stages of development from the egg to the adult stages. SlGSTe2, SlGSTe3, SlGSTs1, SlGSTs3 and SlGSTu1 had higher expression levels in the larval stages than in other stages and their expression levels in the midgut were higher than in other tissues. SlGSTs1 was expressed in the larval midgut but not in the fat body and could be induced by bacterial infections. The expression of SlGSTe1, SlGSTe3, SlGSTs1 and SlGSTs3 was increased by chlorpyrifos to various degrees, while the expression of SlGSTe1, SlGSTe3, SlGSTs1, SlGSTs3 and SlGSTo1 was increased by xanthotoxin. Levels of malonaldehyde, an indicator of oxidative stress, were higher in the larval midgut than in the pupal midgut. Chlorpyrifos induced the malonaldehyde content in the larvae, whereas xanthotoxin did not. It is hypothesized that high expression levels of the midgut SlGSTs might be due to the increased levels of oxidative stress caused by feeding, bacterial infection and xenobiotic compounds.     

Transcobalamin II expression is regulated by transcription factor(s) binding to a hexameric sequence (TGGTCC) in the promoter region of the gene

An isoenzyme of glutathione S-transferase (adGST) was purified from liver intestine of the seashell (Asaphis dichotoma) by GST-Sepharose 4B affinity chromatography followed by reverse-phase HPLC. The enzyme has a pI value of 4.6 and is composed of two subunits each with a molecular weight of 23kDa. It exhibits different catalytic activities toward the substrates 1-chloro-2,4-dinitrobenzene, 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole, ethacrynic acid, and p-nitrophenyl acetate and, fascinatingly, shows high activity toward CDNB. The amino acid composition of adGST was determined and found to be very similar to the Sloane squid GSTs. N-terminal analysis of the first 15 residues of adGST revealed that it has 73% sequence identity with the pig roundworm GSTs. The adGST shows characteristics similar to those of class sigma GSTs, as was indicated by its substrate specificity, N-terminal amino acid sequence, and amino acid composition.     

Differential roles of 3H-1,2-dithiole-3-thione-induced glutathione, glutathione S-transferase and aldose reductase in protecting against 4-hydroxy-2-nonenal toxicity in cultured cardiomyocytes

4-hydroxy-2-nonenal (HNE) plays an important role in the pathogenesis of cardiac disorders. While conjugation with glutathione (GSH) catalyzed by GSH S-transferase (GST) has been suggested to be a major detoxification mechanism for HNE in target cells, whether chemically upregulated cellular GSH and GST afford protection against HNE toxicity in cardiac cells has not been investigated. In addition, the differential roles of chemically induced GSH and GST as well as other cellular factors in detoxifying HNE in cardiomyocytes are unclear. In this study, we have characterized the induction of GSH and GST by 3H-1,2-dithiole-3-thione (D3T) and the protective effects of the D3T-elevated cellular defenses on HNE-mediated toxicity in rat H9C2 cardiomyocytes. Treatment of cardiomyocytes with D3T resulted in a significant induction of both GSH and GST as well as the mRNA expression of gamma-glutamylcysteine ligase catalytic subunit and GSTA. Both GSH and GST remained elevated for at least 72 h after removal of D3T from the culture media. Treatment of cells with HNE led to a significant decrease in cell viability and an increased formation of HNE-protein adducts. Pretreatment of cells with D3T dramatically protected against HNE-mediated cytotoxicity and protein-adduct formation. HNE treatment caused a significant decrease in cellular GSH level, which preceded the loss of cell viability. Either depletion of cellular GSH by buthionine sulfoximine (BSO) or inhibition of GST by sulfasalazine markedly sensitized the cells to HNE toxicity. Co-treatment of cardiomyocytes with BSO was found to completely block the D3T-mediated GSH elevation, which however failed to reverse the cytoprotective effects of D3T, suggesting that other cellular factor(s) might be involved in D3T cytotprotection. In this regard, D3T was shown to induce cellular aldose reductase (AR). Surprisingly, inhibition of AR by sorbinil failed to potentiate HNE toxicity in cardiomyocytes. In contrast, sorbinil dramatically augmented HNE cytotoxicity in cells with GSH depletion induced by BSO. Similarly, in BSO-treated cells, D3T cytoprotection was also largely reversed by sorbinil, indicating that AR played a significant role in detoxifying HNE only under the condition of GSH depletion in cardiomyocytes. Taken together, this study demonstrates that D3T can induce GSH, GST, and AR in cardiomyocytes, and that the above cellular factors appear to play differential roles in detoxification of HNE in cardiomyocytes.     

Depletion of 4-hydroxynonenal in hGSTA4-transfected HLE B-3 cells results in profound changes in gene expression

Previously, we have shown that overexpression of 4-hydroxy-2-nonenal (HNE)-detoxifying enzyme glutathione S-transferase A4-4 (hGSTA4-4) in human lens epithelial cells (HLE B-3) leads to pro-carcinogenic phenotypic transformation of these cells [R. Sharma, et al. Eur. J. Biochem. 271 (2004) 1960-1701]. We now demonstrate that hGSTA4-transfection also causes a profound change in the expression of genes involved in cell adhesion, cell cycle control, proliferation, cell growth, and apoptosis, which is consistent with phenotypic changes of the transformed cells. The expression of p53, p21, p16, fibronectin 1, laminin gamma1, connexin 43, Fas, integrin alpha6, TGFalpha, and c-jun was down-regulated, while the expression of protein kinase C beta II (PKCbetaII), c-myc, cyclin-dependent kinase 2 (CDK2), and TGFbeta was up-regulated in transfected cells. These results demonstrate that HNE serves as a crucial signaling molecule and, by modulating the expression of genes, can influence cellular functions.     

Curcumin modulates drug metabolizing enzymes in the female Swiss Webster mouse

Curcumin, the yellow pigment found in turmeric, exhibits potent chemopreventative properties in both in vivo and in vitro cancer models. We hypothesized that this effect may occur via curcumin-mediated changes in enzymes involved in both carcinogen bioactivation and estrogen metabolism. Female Swiss Webster mice were treated with either curcumin (200 mg/kg or 400 mg/kg, p.o.) or vehicle control for 1 or 2 weeks. The results demonstrated that curcumin had no effect on the catalytic activities of ovarian aromatase, hepatic catechol-O-methyltransferase or hepatic UDP-glucuronosyltransferase. However, both doses of curcumin caused a 25% decrease in CYP1A catalytic activity, but not polypeptide levels, following 2 weeks of treatment. Additionally, following 2 weeks of curcumin at 400 mg/kg, there was a 20% decrease in the catalytic activity and a 28% decrease in polypeptide levels of CYP3A. While 2 weeks of curcumin treatment (400 mg/kg) caused a 20% increase in glutathione S-transferase activity, there was no parallel increase in hepatic stores of the co-factor glutathione. In conclusion small changes in CYP1A, CYP3A and GST following long term treatment (2 weeks) suggest that the combination of all three metabolic pathways may play a small role in curcumin's chemopreventative action.     

Effects of DIMBOA on detoxification enzymes of the aphid Rhopalosiphum padi (Homoptera: aphididae)

The presence of glutathione transferases and esterase activity was investigated in Rhopalosiphum padi and the effects of the cereal hydroxamic acid, 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) on these detoxification enzymes was studied. Activity of glutathione S-transferases and general esterases was determined for adult aphids feeding on a natural diet lacking DIMBOA and on an artificial DIMBOA-containing diet for 48 hours. In vivo, DIMBOA in the diet inhibited the activities of esterases by 50-75% at all concentrations tested (0.5-4 mM). The activity of glutathione transferase was inhibited to a lesser extent (30%) at the higher concentrations of DIMBOA. In vitro, DIMBOA generally inhibited the activity of esterases with an IC(50) of 33 micro M, and had a slight inhibitory effect on glutathione S-transferases. These effects of DIMBOA could make the aphids vulnerable to electrophilic agents and insecticides which may be metabolized via esterases and GSTs. In cereals, therefore, DIMBOA may act by interfering with esterase- or GST-mediated detoxification of xenobiotics by aphids.     

Expression profiles of seven glutathione S-transferase (GST) genes in cadmium-exposed river pufferfish (Takifugu obscurus)

Glutathione S-transferase (GST; EC 2.5.1.18) plays a critical role in detoxification pathways. In this study, we report cloning and expression of seven genes of the GST family of the pufferfish Takifugu obscurus together with mRNA tissue distribution pattern and time-course of expression in response to exposure to cadmium. At basal levels of tissue expression, GST-Mu is highly expressed in liver compared with other tissues. When fish were exposed to cadmium (5 mg/L for 96 h), expression of GST-MAPEG, GST-Mu, GST-Omega, and GST-Zeta was greatly increased, whereas GST-Alpha and GST-Kappa genes showed no significant response. These findings suggest that gene expression of a number of GST isoforms in T. obscurus is modulated in response to exposure to cadmium. We propose GST-Mu, GST-Theta, and GST-Zeta as candidate biomarkers for heavy metal exposure in this fish.     

Glutathione S-transferases as antioxidant enzymes: small cell lung cancer (H69) cells transfected with hGSTA1 resist doxorubicin-induced apoptosis

It has been suggested that the alpha-class glutathione S-transferases (GSTs) protect various cell types from oxidative stress and lipid peroxidation (LPO). In order to examine the protective role of alpha-class GST isozyme hGSTA1-1 against doxorubicin (DOX)-induced lipid peroxidation, cytotoxicity, and apoptosis, human small cell lung cancer (SCLC) H69 cells were stably transfected with hGSTA1. Immunological and biochemical characterization of hGSTA1-transfected cells revealed the expression of functionally active hGSTA1-1 localized near the cellular plasma membranes. hGSTA1-transfected cells acquired significantly increased resistance to the DOX-induced cytotoxicity by suppressing lipid peroxidation levels in these cells. Overexpression of hGSTA1-1 in cells inhibited DOX-mediated depletion of GSH and higher GSH levels were found in DOX-treated hGSTA1-transfected cells as compared with empty vector-transfected controls. hGSTA1-1 overexpression also provided protection to cells from DOX-induced apoptosis by inhibiting phosphorylation of c-Jun-N-terminal kinases (JNK), caspase-3 activation, and by preserving the levels of anti-apoptotic protein Bcl-2. These results are consistent with the idea that the alpha-class GSTs provide protection against oxidative stress by attenuating lipid peroxidation and these enzymes can modulate signaling for apoptosis.     

Disruption of Smad5 gene induces mitochondria-dependent apoptosis in cardiomyocytes

Our previous studies have shown that SMAD5, an important intracellular mediator of transforming growth factor beta (TGF-beta) family, is required for normal development of the cardiovascular system in vivo. In the current study, we reported that the lack of the Smad5 gene resulted in apoptosis of cardiac myocytes in vivo. To further investigate the mechanism of the Smad5 gene in cardiomyocyte apoptosis, the embryonic stem (ES) cell differentiation system was employed. We found that the myotubes that differentiated from the homozygous Smad5ex6/ex6 mutant ES cells underwent collapse and degeneration during the late stages of in vitro differentiation, mimicking the in vivo observation. By electron microscopy, abnormal swollen mitochondria were observed in cardiomyocytes both from Smad5-deficient embryos and from ES-differentiated cells. There was also a significant reduction in mitochondrial membrane potential (Deltapsi m) and a leakage of cytochrome c from mitochondria into the cytosol of myocytes differentiated from Smad5 mutant ES cells. The expression of p53 and p21 was found to be elevated in the differentiated Smad5 mutant myocytes, and this was accompanied by an up-regulation in caspase 3 expression. These results suggest that the Smad5-mediated TGF-beta signals may protect cardiomyocytes from apoptosis by maintaining the integrity of the mitochondria, probably through suppression of p53 mediated pathways.     

Antioxidant defense markers modulated by glutathione S-transferase genetic polymorphism: results of lung cancer case–control study

Oxidative stress and xenobiotic metabolizing enzymes are suspected to be related to carcinogenesis by different cellular mechanisms. Hence, our study aimed at identifying potential relationships between antioxidant defense parameters measured in blood and glutathione S-transferase (GST) genetic polymorphisms of four GST izoenzymes in lung cancer patients and reference individuals. The case-control study included 404 lung cancer patients and 410 non-cancer subjects as controls, matched by age, gender and place of living (central Poland). In control subjects with GSTM3*A/*A, GSTT1 null, GSTM1 null + GSTT1 null, GSTM3*A/*A + GSTT1 null genotype, glutathione peroxidase activity was significantly higher (P < 0.05) than in controls possessing respective potential protective GST genotypes. Controls with GSTM3*A/*A + GSTP1*B genotype presented significantly higher ceruloplasmin activity (P < 0.05) than GSTM3*B + GSTP1*A/*A carriers. Zinc level was significantly higher (P < 0.05) in controls and cases with GSTP1*B + GSTT1 null genotype and in cases with GSTM1 null + GSTP1*B genotype, when compared with respective potential protective GST genotypes. This case-control study indicates that particular defective GST genotypes may enhance the defense against oxidative stress. The potential relationship between the investigated antioxidative enzymes and microelements, and common functional genetic polymorphism of GST was observed mostly in control subjects.     

Coordinate induction of glutathione biosynthesis and glutathione-metabolizing enzymes is correlated with salt tolerance in tomato

The acclimation of reduced glutathione (GSH) biosynthesis and GSH-utilizing enzymes to salt stress was studied in two tomato species that differ in stress tolerance. Salt increased GSH content and GSH:GSSG (oxidized glutathione) ratio in oxidative stress-tolerant Lycopersicon pennellii (Lpa) but not in Lycopersicon esculentum (Lem). These changes were associated with salt-induced upregulation of gamma-glutamylcysteine synthetase protein, an effect which was prevented by preincubation with buthionine sulfoximine. Salt treatment induced glutathione peroxidase and glutathione-S-transferase but not glutathione reductase activities in Lpa. These results suggest a mechanism of coordinate upregulation of synthesis and metabolism of GSH in Lpa, that is absent from Lem.     

Susceptibility to oxidative stress and modulated expression of antioxidant genes in the copper-exposed polychaete Perinereis nuntia

To identify and evaluate potentially useful biomarkers for oxidative stress as early warning indices in the polychaete, Perinereis nuntia, we exposed P. nuntia to copper (Cu) and measured several biomarker enzymes (glutathione S-transferase; GST, glutathione peroxidase; GPx, Metallothionein-like protein; MTLPs, and catalase; CAT) and genes (Pn-GSTs, Pn-CAT, and Pn-MT) with a cellular oxidative index, reactive oxygen species (ROS) level. Accumulated Cu concentrations in P. nuntia increased in a time-dependent manner. Intracellular ROS reached high levels 6h after exposure in P. nuntia with an increase of GST activity and glutathione (GSH) content. Particularly, GSH in polychaetes showed a positive correlation with Cu contents accumulated in P. nuntia. Messenger RNA expressions of GST sigma and GST omega showed relatively high expressions at 50 μg/L of Cu exposure, even though the moderate increase of rest of GST isoforms was also observed. Also regarding long-term exposure, we reared P. nuntia in sediments for 15 days, and found that there was an obvious increase of Pn-GSTs, Pn-CAT, and Pn-MT genes with elevated concentrations of Cu and Cd in polychaete body, compared to initial levels, suggesting that P. nuntia in sediment was affected by metals as well as by other organic pollutants to induce oxidative stress genes and enzymes. These findings suggest that oxidative stress is a potential modulator of defense system of P. nuntia. Several potential biomarker genes are available as early warning signals for environmental biomonitoring.     

Effect of copper exposure on GST activity and on the expression of four GSTs under oxidative stress condition in the monogonont rotifer, Brachionus koreanus

Glutathione S-transferases (GSTs; EC 2.5.1.18) are major enzymes that function in Phase II detoxification reactions by catalyzing the conjugation of reduced glutathione through cysteine thiol. In this study, we cloned and sequenced four GST genes from the monogonont rotifer Brachionus koreanus. The domain regions of four Bk-GSTs showed a high similarity to those of other species. In addition, to evaluate the potential of GST genes as an early warning signal for oxidative stress, we exposed sublethal concentrations of copper (Cu) to B. koreanus and measured glutathione (GSH) contents and several antioxidant enzymes such as glutathione S-transferase (GST), glutathione peroxidase (GPx; EC 1.11.1.9), and glutathione reductase (GR; EC 1.8.1.7). The reactive oxygen species (ROS) at 12 h and 24 h after copper exposure increased significantly. GSH contents however did not increase significantly and even it decreased at 0.24 mg/L at 12 h. The activities of several antioxidant enzymes, particularly GPx and GR, showed a dramatic increase in 0.24 mg/L of CuCl₂. Messenger RNAs of each Bk-GST showed different patterns of modulations according to GST types, and particularly, Bk-GST-omega, Bk-GST-sigma, and Bk-GST zeta genes were highly sensitive to Cu. These results indicate that Bk-GSTs, functioning as one of the enzymatic defense mechanisms particularly in the early stage of oxidative stress response, were induced by Cu exposure. This also suggests that these genes and related enzymes have a potential as biomarkers for a more sensitive initial stress response.     

Polymorphism of glutathione S-transferase P1 gene affects human vitamin C metabolism

There are large inter-individual differences in the metabolism of vitamin C (VC), which is composed of both ascorbic acid (AsA) and dehydroascorbic acid (DAsA). AsA is oxidized to DAsA in a series of xenobiotic reactions. Thus, the effects of polymorphism A313G (Ile105Val) in the gene for glutathione S-transferases P1 (GSTP1), one of the most active xenobiotic enzymes, on human VC metabolism were studied. The variant frequency of GSTP1 among the present subjects (n = 210) was AA 71.0%; GA 27.0% and GG 1.9%. At 24 h after administration of 1 mmol of VC to young women (n = 17; age, 21.0 ± 1.1 y), total VC excretion (46.7 ± 18.1 mg) by AA homozygotes of GSTP1 was greater (p < 0.0069) than that (28.2 ± 14.0 mg) by GA heterozygotes. One hour after administration of VC, blood total VC levels were also significantly different (p < 0.0036) between the homozygotes and heterozygotes. The effects of other polymorphisms in xenobiotic enzymes on VC metabolism were small.     

Glutathione,S-substituted glutathiones,and leukotriene C4 as substrates for peptidylglycine alpha-amidating monooxygenase

The C-terminal alpha-amide moiety of most peptide hormones arises by the posttranslational cleavage of a glycine-extended precursor in a reaction catalyzed by bifunctional peptidylglycine alpha-amidating monooxygenase (PAM). Glutathione and the S-alkylated glutathiones have a C-terminal glycine and are, thus, potential substrates for PAM. The addition of PAM to glutathione, a series of S-alkylated glutathiones, and leukotriene C(4) results in the consumption of O(2) and the production of the corresponding amidated peptide and glyoxylate. This reaction proceeds in two steps with the intermediate formation of a C-terminal alpha-hydroxyglycine-extended peptide. Amidated glutathione (gammaGlu-Cys-amide) is a relatively poor substrate for glutathione S-transferase with a V/K value that is 1.3% of that for glutathione. Peptide substrates containing a penultimate hydrophobic or sulfur-containing amino acid exhibit the highest (V/K)(app) values for PAM-catalyzed amidation. The S-alkylated glutathiones incorporate both features in the penultimate position with S-decylglutathione having the highest (V/K)(app) of the substrates described in this report.     

Expression of selenocysteine-containing glutathione S-transferase in Escherichia coli

Evolution of a probable 'glutathione-binding ancestor' resulting in a common thioredoxin-fold for glutathione S-transferases and glutathione peroxidases may possibly suggest that a glutathione S-transferase could be engineered into a selenium-containing glutathione S-transferase (seleno-GST), having glutathione peroxidase (GPX) activity. Here, we addressed this question by production of such protein. In order to obtain a recombinant seleno-GST produced in Escherichia coli, we introduced a variant bacterial-type selenocysteine insertion sequence (SECIS) element which afforded substitution with selenocysteine for the catalytic Tyr residue in the active site of GST from Schistosoma japonica. Utilizing coexpression with the bacterial selA, selB, and selC genes (encoding selenocysteine synthase, SelB, and tRNA(Sec), respectively) the yield of recombinant seleno-GST was about 2.9 mg/L bacterial culture, concomitant with formation of approximately 85% truncation product as a result of termination of translation at the selenocysteine-encoding UGA codon. The mutations inferred as a result of the introduction of a SECIS element did not affect the glutathione-binding capacity (Km = 53 microM for glutathione as compared to 63 microM for the wild-type enzyme) nor the GST activity (kcat = 14.3 s(-1) vs. 16.6 s(-1)), provided that the catalytic Tyr residue was intact. When this residue was changed to selenocysteine, however, the resulting seleno-GST lost the GST activity. It also failed to display any novel GPX activity towards three standard peroxide substrates (hydrogen peroxide, butyl hydroperoxide or cumene hydroperoxide). These results show that recombinant selenoproteins with internal selenocysteine residues may be heterologously produced in E. coli at sufficient amounts for purification. We also conclude that introduction of a selenocysteine residue into the catalytic site of a glutathione S-transferase is not sufficient to induce GPX activity in spite of a maintained glutathione-binding capacity.     

S-allylcysteine ameliorates isoproterenol-induced cardiac toxicity in rats by stabilizing cardiac mitochondrial and lysosomal enzymes

This study was aimed to evaluate the preventive role of S-allylcysteine (SAC) on mitochondrial and lysosomal enzymes in isoproterenol (ISO)-induced rats. Male albino Wistar rats were pretreated with SAC (50, 100 and 150 mg/kg) daily for a period of 45 days. After the treatment period, ISO (150 mg/kg) was subcutaneously injected to rats at an interval of 24 h for two days. The activities of heart mitochondrial enzymes (isocitrate dehydrogenase, succinate dehydrogenase, malate dehydrogenase and alpha-ketoglutarate dehydrogenase) and respiratory chain enzymes (NADH dehydrogenase and cytochrome C oxidase) were decreased significantly (p<0.05) in ISO-induced rats. The activities of lysosomal enzymes (beta-glucuronidase, beta-N-acetyl glucosaminidase, beta-galactosidase, cathepsin-D and acid phosphatase) were increased significantly (p<0.05) in serum and heart of ISO-induced rats. Pretreatment with SAC (100 mg/kg and 150 mg/kg) for a period of 45 days increased significantly (p<0.05) the activities of mitochondrial and respiratory chain enzymes and decreased the activities of lysosomal enzymes significantly (p<0.05) in ISO-induced rats. Oral administration of SAC (50, 100 and 150 mg/kg) for a period of 45 days to normal rats did not show any significant (p<0.05) effect in all the parameters studied. The altered electrocardiogram (ECG) of ISO-treated rats was also restored to near normal by treatment with SAC (100 and 150 mg/kg). These results confirm the efficacy of SAC in alleviating ISO-induced cardiac damage.