Effects Of Schisandrin Research Articles

(–)Schisandrin B is more potent than its enantiomer in enhancing cellular glutathione and heat shock protein production as well as protecting against oxidant injury in H9c2 cardiomyocytes

Effects of schisandrin B enantiomers ((+)Sch B and (-)Sch B) treatment on cellular reduced glutathione (GSH) level and heat shock protein (Hsp)25/70 production were investigated in H9c2 cardiomyocytes. (+)Sch B and (-)Sch B at 6.25 muM produced a time-dependent and biphasic change in cellular GSH level and Hsp25/70 production, with the stimulatory effect of (-)Sch B being more potent. The GSH- and Hsp-enhancing effects were accompanied by a parallel cytoprotection against xanthine oxidase/xanthine-induced toxicity, with the biphasic time course of (+)Sch B- or (-)Sch B-induced protection being superimposed with that of the increase in GSH level but not Hsp25/70 production. The results indicate that (-)Sch B produces more potent enhancing effects on cellular GSH and Hsp production as well as protection against oxidative injury than (+)Sch B in cardiomyocytes.

Effects of Schisandrin B Enantiomers on Cellular Glutathione and Menadione Toxicity in AML12 Hepatocytes

Effects of schisandrin B enantiomer ((+)Sch B and (–)Sch B) treatment on the reduced cellular glutathione (GSH) level and susceptibility to menadione-induced toxicity were investigated and compared in AML12 hepatocytes. (+)Sch B or (–)Sch B treatment at 6.25 µmol/l produced a time-dependent change in cellular GSH level, with the maximal stimulation occurring 16 h after dosing. (+)Sch B/(–)Sch B pretreatment for 16 h dose-dependently protected against menadione toxicity, with the maximum degree of protection observable at 6.25 µmol/l and the extent of protection afforded by (–)Sch B being larger than that of (+)Sch B. The cytoprotection was associated with a parallel enhancement in cellular GSH level in both non-menadione (control) and menadione-intoxicated cells. While the GSH depletion produced by buthionine sulfoximine/phorone treatment largely abrogated the cytoprotective action of (+)Sch B/(–)Sch B, it almost completely abolished the GSH-enhancing effect of (+)Sch B and (–)Sch B in both control and menadione-treated cells. Both (+)Sch B and (–)Sch B treatments increased the GSH reductase activity in control and menadione-treated cells, with the stimulatory action of (–)Sch B being more potent than that of (+)Sch B in the control condition. (+)Sch B and (–)Sch B also enhanced the γ-glutamate cysteine ligase activity in menadione-intoxicated cells. The results indicate that (–)Sch B is more effective than (+)Sch B in enhancing cellular GSH and protecting against oxidant injury in hepatocytes.

Effects of schisandrin B on reversing multidrug resistance in human breast cancer cells transfected with mdr1 gene

To investigate the multidrug resistance (MDR) reversal activity of schisandrin B (SchB) in transfected human breast cancer cell line MCF-7/MDR1. Human breast cancer cells of the line MCF-7 were cultured and transfected with mdr1 gene so as to establish a P-glycoprotein (P-gp) stable-expressing cell line MCF-7/MDR1. The expression of P-gp in the MCF-7/mdr1 cells was assayed by flow cytometry using fluorescent antibody. MCF-7 cells transfected with blank plasmid MCF-7/neo was used as controls. Adriamycin (ADR), verapamil (VER), pacilitaxel (taxol), and homoharringtonine (HHT) were added into the culture fluid of the MCF-7/mdr1 cells and MTT method was used to detect the IC(50) of these drugs. The culture fluid of the MCF-7/MDR1 cells was added with SchB of the concentrations of 2.5, 12.5, 25, and 50 micromol/L and then added with ADR1 cells, MTT method was used to calculate the reversal effect (RF) of SchB on the MDR phenotype of the MCF-7/mdr1 cells. MTT method was used to calculate the RF. Another culture fluid of MCF-7/mdr1 cells was added with 25 micromol/L SchB and then with ADR, vincristine (VCR), pacilitaxel, and HHT with that added with 10 micromol/L VER as control. After treatment with SchB the MF7/mgr1 cells were co-incubated with 5 micromol/L rhodamine (Rh)-123, then flow cytometry was used to detect the accumulation of Rh-123 within the cells. After treatment with 25 micromol/L SchB for 0, 0.5, 1, 6, 24, 48, and 72 hours flow cytometry was used to detect the P-gp expression in the MF7/mgr1 cells. The transfected MCF-7/MDR1 cells overexpressed P-gp and exhibited resistance to multiple drugs, including ADR, VCR, pacilitaxel and HHT. SchB (25 micromol/L) significantly enhanced the sensitivity of the MCF-7/MDR1 cells to above mentioned chemotherapeutic agents, with a reversal factors of 6.03 to 23.94 times. The effect of SchB (25 micromol/L) on Rh-123 accumulation in MDR cells was equivalent to that of 10 micromol/L VER, however no significant difference was found in the effect of SchB (25 micromol/L) on the P-gp expression in the MCF-7/MDR1 cells. SchB is able to restore the drug sensitivity in the transfected MCF7/MDR1 cells, with a possible mechanism of increasing the drug influx via inhibiting the P-gp function.

Schisandrin B modulates the ischemia-reperfusion induced changes in non-enzymatic antioxidant levels in isolated-perfused rat hearts.

Isolated Langendorff-perfused rat hearts were subjected to a fixed period of ischemia followed by increasing periods of reperfusion for investigating the changes in the extent of ischemia-reperfusion (IR) injury and tissue levels of non-enzymatic antioxidants. Effects of schisandrin B (Sch B) and (+/-) alpha-lipoic acid (LA) pretreatment were also examined. A 40-min of ischemia (40-I) followed by 20- or 40-min of reperfusion (20-R or 40-R) caused sustainable tissue damage in isolated hearts, as indicated by the increased extent of lactate dehydrogenase (LDH) leakage and impaired contractile force. The myocardial IR injury was associated with a marked decrease in tissue ascorbic acid (V(C)) level. However, myocardial reduced glutathione (GSH) and alpha-tocopherol (V(E)) levels remained relatively unchanged except under a more severe IR condition (40-I, 40-R). Pretreating rats with Sch B or LA at a daily dose of 1.2 mmol/kg for 3 days protected against IR injury in isolated hearts to varying degrees. While only Sch B pretreatment could improve the recovery of contractile force, LA pretreatment produced a better inhibitory effect on LDH leakage. The protection against IR injury was associated with significant increases in myocardial V(E) and V(C) levels in both Sch B and LA pretreated hearts. The ensemble of results suggests that the cardioprotection afforded by Sch B or LA pretreatment may at least in part be attributed to the modulation on the interplay among non-enzymatic antioxidants under oxidative stress induced by IR.

Effects of schisandrin B pretreatment on tumor necrosis factor-α induced apoptosis and Hsp70 expression in mouse liver

Tumor necrosis factor-alpha (TNFalpha) could cause apoptosis in hepatic tissue of D-galactosamine sensitized mice, as evidenced by the increase in the extent of DNA fragmentation. The hepatic apoptosis induced by TNFalpha was associated with hepatocellular damage as assessed by plasma alanine aminotransferase activity. Schisandrin B (Sch B) pretreatment at daily doses ranging from 0.5 to 2 mmol/kg for 3 days caused a dose-dependent protection against TNFalpha-induced apoptosis in mice. The hepatoprotection was accompanied by a parallel reduction in the extent of hepatocellular damage. The same Sch B pretreatment regimens increased hepatic Hsp70 level in a dose-dependent manner. The relevance of Sch B-induced increase in Hsp70 expression to the prevention of TNFalpha-triggered hepatic apoptosis remains to be elucidated.

Differential effect of schisandrin B and dimethyl diphenyl bicarboxylate (DDB) on hepatic mitochondrial glutathione redox status in carbon tetrachloride intoxicated mice.

The effects of schisandrin B (Sch B), a dibenzocyclooctadiene derivative isolated from the fruit of Schisandra chinensis, and dimethyl diphenyl bicarboxylate (DDB), a synthetic intermediate of schisandrin C (also a dibenzocyclooctadiene derivative), on hepatic mitochondrial glutathione redox status in control and carbon tetrachloride (CCl4)-intoxicated mice were examined. Treating mice with Sch B or DDB at a daily oral dose of 1 mmol/kg for 3 d did not produce any significant alterations in plasma alanine aminotransferase (ALT) and sorbital dehydrogenase (SDH) activities. CCl4 treatment caused drastic increases in both plasma ALT and SDH activities in mice. Pretreating mice with Sch B or DDB at the same dosage regimen significantly suppressed the CCl4-induced increase in plasma ALT activity, with the inhibitory effect of Sch B being much more potent. Sch B, but not DDB, pretreatment could also decrease the plasma SDH activity in CCl4-intoxicated mice. The lowering of plasma SDH activity, indicative of hepatoprotection against CCl4 toxicity, by Sch B pretreatment was associated with an enhancement in hepatic mitochondrial glutathione redox status as well as an increase in mitochondrial glutathione reductase (mtGRD) activity in both non-CCl4 and CCl4-treated mice. DDB pretreatment, though enhancing both hepatic mitochondrial glutathione redox status and mtGRD activity in control animals, did not produce any beneficial effect in CCl4-treated mice. The difference in hepatoprotective action against CCl4 toxicity between Sch B and DDB may therefore be related to their ability to maintain hepatic mitochondrial glutathione redox status under oxidative stress condition.

Schisandrin B protects against myocardial ischemia-reperfusion injury by enhancing myocardial glutathione antioxidant status.

The effects of Schisandrin B (Sch B) and dimethyl-4,4'-dimethoxy-5,6,5',6'dimethylene-dioxy-biphenyl-2,2'-+ ++bicarboxylate (DDB) treatment on myocardial ischemia-reperfusion (IR) injury in isolated perfused rat hearts were examined under both in vitro and ex vivo conditions. In vitro administration of liposome-entrapped Sch B or DDB during reperfusion did not protect against myocardial IR injury, whereas ascorbic acid or Trolox supplemented perfusate produced protective effect, as evidenced by the significant decrease in the extent of lactate dehydrogenase leakage as well as an improvement in contractile force recovery. Myocardial protection afforded by N-acetyl-L-cysteine supplemented perfusate was not accompanied by the enhancement in contractile force recovery. In ex vivo experiment, pretreatment of Sch B (0.6/1.2 mmol/kg/day x 3) protected against IR-induced myocardial damage in a dose-dependent manner. The myocardial protection was associated with an enhancement in myocardial glutathione antioxidant status, as indicated by significant reductions in both the extent of IR-induced reduced glutathione depletion and inhibition of Se-glutathione peroxidase and glutathione reductase activities. In contrast, the inability of DDB pretreatment to enhance myocardial glutathione antioxidant status resulted in a failure in preventing IR injury. The ensemble of results suggests that the myocardial protection afforded by Sch B pretreatment, which was unlikely due to free radical scavenging action, may be mainly mediated by the enhancement of myocardial glutathione antioxidant status, particularly under oxidative stress conditions.

Effects of Schisandrin B and alpha-tocopherol on lipid peroxidation, in vitro and in vivo.

Effects of Schisandrin B (Sch B) and alpha-tocopherol (alpha-TOC) on ferric chloride (Fe3+) induced oxidation of erythrocyte membrane lipids in vitro and carbon tetrachloride (CCl4) induced lipid peroxidation in vivo were examined. While alpha-TOC could produce prooxidant and antioxidant effect on Fe(3+)-induced lipid peroxidation, Sch B only inhibited the peroxidation reaction. Pretreatment with alpha-TOC (3 mmol/kg/day x 3) did not protect against CCl4-induced lipid peroxidation and hepatocellular damage in mice, whereas Sch B pretreatment (0.3 mmol/3.0 mmol/kg/day x 3) produced a dose-dependent protective effect on the CCl4-induced hepatotoxicity. The ensemble of results suggests that the ability of Sch B to inhibit lipid peroxidation, while in the absence of pro-oxidant activity, may at least in part contribute to its hepatoprotective action.

The crucial antioxidant action of schisandrin B in protecting against carbon tetrachloride hepatotoxicity in mice: A comparative study with butylated hydroxytoluene

A comparison between the effects of schisandrin B (Sch B) and butylated hydroxytoluene (BHT) treatments on hepatic antioxidant status was made to identify the critical antioxidant action of Sch B involved in hepatoprotection in mice. Whereas Sch B treatment (3 mmol/kg/day × 3, p.o.) increased the hepatic mitochondrial-reduced glutathione (GSH) level, BHT treatment at the same dosage regimen decreased it. However, both Sch B and BHT increased, albeit to a different extent, the activity of mitochondrial glutathione reductase. The differential effect of Sch B and BHT treatment on hepatic mitochondrial glutathione status became more apparent after carbon tetrachloride (CCl 4) challenge. Pretreatment with Sch B could sustain the hepatic mitochondrial GSH level in CCl 4-intoxicated mice and protect against CCl 4 hepatotoxicity. BHT pretreatment did not produce any protective effect on CCl 4-induced GSH depletion in mitochondrion and hepatocellular damage. Although both Sch B and BHT treatments increased hepatic ascorbic acid (VC) level in control animals, only Sch B pretreatment sustained a high hepatic VC level in CCl 4-intoxicated mice. Moreover, Sch B pretreatment prevented the CCl 4-induced decrease in the hepatic α-tocopherol (VE) level. However, Sch B inhibited NADPH oxidation in mouse liver microsomes incubated with CCl 4 in vitro, whereas BHT stimulated this oxidation. The ensemble of results suggests that the ability to sustain the hepatic mitochondrial GSH level and the hepatic VC and VE levels may represent the crucial antioxidant action of Sch B in protection against CCl 4 hepatotoxicity. The possible inhibition of CCl 4 metabolism by Sch B may also contribute to its hepatoprotective action.

Effect of schisandrin B on hepatic glutathione antioxidant system in mice: protection against carbon tetrachloride toxicity.

Pretreating female Balb/c mice with schisandrin B (Sch B) at increasing daily doses (1-4 mmol/kg) for 3 days caused dose-dependent increases in hepatic glutathione S-transferase (GST) and glutathione reductase (GRD) activities. However, the activities of glucose-6-phosphate dehydrogenase (G6PDH), Se-glutathione peroxidase (GPX), and gamma-glutamylcysteine synthetase (GCS) were down-regulated to varying degrees in a dose-dependent manner. While there were biphasic changes in hepatic reduced glutathione (GSH) level as well as susceptibility of hepatic tissue homogenates to in vitro peroxide-induced GSH depletion, a gradual decrease in hepatic malondialdehyde content was observed. The beneficial effect of Sch B on the hepatic GSH anti-oxidant system became more evident after CCl4 challenge. The same Sch B pretreatment regimen caused a dose-dependent protection against carbon tetrachloride (CCl4)-induced hepatotoxicity. The hepatoprotection was associated with significant enhancement in hepatic GSH status, as indicated by the substantial increase in tissue GSH levels and the corresponding decrease in susceptibility of tissue homogenates to GSH depletion. Where the activities of GST and GRD were increased linearly over non-CCl4 control values, there was also a gradual elevation in G6PDH activity upon administration of increasing doses of Sch B. In contrast, GPX activity was moderately down-regulated. The ensemble of results suggests that the hepatoprotection afforded by Sch B pretreatment may mainly be attributed to the enhancement in the functioning of the hepatic GSH anti-oxidant system, possibly through stimulating the activities of GSH related enzymes.