Glutathione

Common Name: GSH

Clinical Name: Glutathione

Summary

Glutathione (GSH)

forms/synonyms: Reduced L-glutathione

chemical name: Gamma-L-glutamyl-L-cysteninylglycine.

overview of interactions:
• nutrient affecting drug toxicity: Cisplatin

• nutrient affected by drug and affecting drug toxicity: Haloperidol

chemistry/function: L-Glutathione is a biologically active sulfur amino acid tripeptide compound containing three amino acids L-Cysteine, L-Glutamic Acid and Glycine. Most glutathione is found in the liver where it detoxifies many harmful compounds to be excreted thru the bile. Some glutathione can also be found in red and white blood cells, the lungs and the intestinal tract. The primary biological function of glutathione is to act as a non-enzymatic reducing agent to help keep cysteine thiol side chains in a reduced state on the surface of proteins. Reduced glutathione is involved in the synthesis and repair of DNA, helps to recycle vitamins C and E, blocks free radical damage and enhances the antioxidant activity of vitamin C, facilitates the transport of amino acids, and plays a critical role in the detoxification of harmful compounds. It is also the base material for several other key antioxidant enzyme systems including glutathione-peroxidase, glutathione-reductase, and glutathione-transferase. Declines in glutathione concentrations in intracellular fluids correlate directly with indicators of aging.

dietary sources: Glutathione is derived from L-Cysteine, L-Glutamic Acid and Glycine and is not consumed directly as a food constituent. Glutathione levels are enhanced via intake of vitamin C.

supplemental sources: A daily dose of 500 mg of vitamin C may be adequate to elevate and maintain reduced glutathione concentrations in the blood. In contrast, direct consumption of glutathione orally does not seem to be an effective means of enhancing liver and intracellular gltathione levels. Following a small human study with seven subjects Witschi et al concluded that "because of hydrolysis of glutathione by intestinal and hepatic gamma-glutamyltransferase, dietary glutathione is not a major determinant of circulating glutathione, and it is not possible to increase circulating glutathione to a clinically beneficial extent by the oral administration of a single dose of 3 g of glutathione". On the other hand, intravenous glutathione administration may provide a direct and effective route for increasing intracellualr glutathione levels. Evidence indicates that oral consumption of NAC (N-Acetyl-Cysteine) may be an effective, but not necessarily safe or efficient, means of enhancing glutathione levels.
(Johnston CS, et al. Am J Clin Nutr. 1993 Jul;58(1):103-105; Witschi A, et al. Eur J Clin Pharmacol. 1992;43(6):667-669.)

deficiency: Symptoms of glutathione deficiency may include coordination problems, generalized cell damage, mental disorders, various nervous system disorders, tremors, and twitching. Red cells are prone to burst, white blood cells decline in function, and nerve tissue degenerates. A deficiency of intracellular glutathione has been associated with a variety of conditions including AIDS, alcohol-induced liver disease and some forms of cancer.

proven or potential therapeutic uses: Antioxidant action, cancer, cataracts, liver disease, macular degeneration.

mechanism: Support of antidoxidant processes.

maintenance dose: Usually not necessary. Optimal levels of intake have not been established. 50 mg is a common dose in supplemental forms.

therapeutic dose: 500 mg a day is used by some practitioners to treat various conditions.

side effects: Glutathione is generally considered to be free of side effects.

toxicity: No toxicities have been reported or suspected as being associated with glutathione.

contraindications: None known, except for use during some forms of chemotherapy and radiation where antioxidants are contraindicated due to their inhibition of the free radical formation which is an intentional part of the therapeutic mechanism.



Interactions

nutrient affecting drug toxicity: Cisplatin

• research: Some human and animal studies have found that intravenous glutathione reduces the neurological toxicity of cisplatin and improves quality of life. More recently, Babu et al reported that administration of glutathione ester modulates the toxic side effect of cisplatin observed in kidney enzymes, and in blood parameters and concluded that glutathione ester plays an important role in protecting against the cisplatin induced nephrotoxicity by inhibiting the accumulation of platinum in kidneys. Even so, there is, as of yet, no conclusive evidence showing the effectiveness of oral glutathione.
(Jones MM, et al. Toxicology 1991;68(3):227-247; Cascinu S, et al. J Clin Oncol 1995;13:26-32; Smyth IF, et al. Ann Oncol 1997;8:569-573; Babu E, et al. Ren Fail 1999 Mar;21(2):209-217.)

• nutritional support: While research with glutathione in research settings appears promising there is, as of yet, no conclusive evidence showing the effectiveness of oral glutathione.

nutrient affected by drug and affecting drug toxicity: Haloperidol

• mechanism: Haloperidol acts through blockade of dopamine receptors leading to increased turnover of dopamine. Increased turnover of dopamine could lead to excessive production of hydrogen peroxide and, thus, generate oxidative stress. Haloperidol administration also appears to result in a loss of glutathione (GSH), a key antioxidant substance naturally occurring in the body.
(Shivakumar BR, et al. J Pharmacol Exp Ther. 1993 Jun;265(3):1137-1141; Rabinovic AD, Hastings TG. Neurochem. 1998 Nov;71(5):2071-2078.)

• research: Balijepalli et al examined the effects of a variety of classical and atypical neuroleptic drugs and found that haloperidol was the most potent inhibitor of mitochondrial NADH ubiquinone oxido-reductase (complex I) activity. They found that in vitro treatment of mouse brain slices with haloperidol resulted in a loss of glutathione (GSH), while pretreatment of slices with GSH and alpha-lipoic acid abolished haloperidol-induced loss of complex I activity.
(Balijepalli S, et al. Neuropharmacology 1999 Apr;38(4):567-577.)

• nutritional support: Preliminary evidence indicates that supplementation with glutathione (and/or alpha-lipoic acid) could potentially reduce depletion of naturally occurring glutathione and other adverse side effects due to use of haloperidol. No definitive advise or dosage recommendations can be offered given the lack of clinical trials. However, physicians experienced in nutritional therapies often suggest 100-200 mg per day of l-glutathione (reduced) for a variety of conditions, including general protective activity. Individuals concerned about preventing the damaging effects of haloperidol should consult their prescribing physician and/or nutritionally trained healthcare professional about possible benefits of supplementing with glutathione (GSH) (and/or alpha-lipoic acid). Glutathione (GSH) has no known toxic effects at commonly used dosages and has never been shown to inhibit the therapeutic efficacy of haloperidol.

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Do not rely solely on the information in this article.

The information presented in Interactions is for informational and educational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, case reports, and/or traditional usage with sources as cited in each topic. The results reported may not necessarily occur in all individuals and different individuals with the same medical conditions with the same symptoms will often require differing treatments. For many of the conditions discussed, treatment with conventional medical therapies, including prescription drugs or over-the-counter medications, is also available. Consult your physician, an appropriately trained healthcare practitioner, and/or pharmacist for any health concern or medical problem before using any herbal products or nutritional supplements or before making any changes in prescribed medications and/or before attempting to independently treat a medical condition using supplements, herbs, remedies, or other forms of self-care.


References

Balijepalli S, Boyd MR, Ravindranath V. Inhibition of mitochondrial complex I by haloperidol: the role of thiol oxidation. Neuropharmacology 1999 Apr;38(4):567-577.
Abstract: We have examined the effects of a variety of classical and atypical neuroleptic drugs on mitochondrial NADH ubiquinone oxido-reductase (complex I) activity. Sagittal slices of mouse brain incubated in vitro with haloperidol (10 nM) showed time- and concentration-dependent inhibition of complex I. Similar concentrations of the pyridinium metabolite of haloperidol (HPP+) failed to inhibit complex I activity in this model; indeed, comparable inhibition was obtained only at a 10000-fold higher concentration of HPP+ (100 microM). Treatment of brain slices with haloperidol resulted in a loss of glutathione (GSH), while pretreatment of slices with GSH and alpha-lipoic acid abolished haloperidol-induced loss of complex I activity. Incubation of mitochondria from haloperidol treated brain slices with the thiol reductant, dithiothreitol, completely regenerated complex I activity demonstrating thiol oxidation as a feasible mechanism of inhibition. In a comparison of different neuroleptic drugs, haloperidol was the most potent inhibitor of complex I, followed by chlorpromazine, fluphenazine and risperidone while the atypical neuroleptic, clozapine (100 microM) did not inhibit complex I activity in mouse brain slices. The present studies support the view that classical neuroleptics such as haloperidol inhibit mitochondrial complex I through oxidative modification of the enzyme complex.

Babu E, Ebrahim AS, Chandramohan N, Sakthisekaran D. Rehabilitating role of glutathione ester on cisplatin induced nephrotoxicity. Ren Fail 1999 Mar;21(2):209-217.
Abstract: Cisplatin caused differential toxic effects on blood glucose and plasma urea, uric acid and creatinine levels. Cisplatin also showed an inhibitory effect on kidney marker enzymes like alkaline phosphatase, acid phosphatase, aspartate aminotransferase and alanine aminotransferase. However, administration of glutathione ester modulates the toxic side effect of cisplatin observed in kidney enzymes, and in blood parameters. It seems that glutathione ester plays an important role in protecting against the cisplatin induced nephrotoxicity by inhibiting the accumulation of platinum in kidneys.

Cascinu S, Cordella L, Del Ferro E, Fronzoni M, Catalano G. Neuroprotective effect of reduced glutathione on cisplatin-based cheniotherapy in advanced gastric cancer: A randomized double-blind placebo-controlled trial. J Clin Oncol 1995 Jan;13(1):26-32.
Abstract: PURPOSE: We performed a randomized double-blind placebo-controlled trial to assess the efficacy of glutathione (GSH) in the prevention of cisplatin (CDDP)-induced neurotoxicity. PATIENTS AND METHODS: Fifty patients with advanced gastric cancer treated with a weekly CDDP-based regimen were included in this study. In patients randomized to receive GSH, GSH was given at a dose of 1.5 g/m2 in 100 mL of normal saline solution over a 15-minute period immediately before CDDP administration, and at a dose of 600 mg by intramuscular injection on days 2 to 5. Normal saline solution was administered to placebo-randomized patients. Clinical neurologic evaluation and electrophysiologic investigations have been performed at baseline and after 9 (CDDP dose, 360 mg/m2) and 15 (CDDP dose, 600 mg/m2) weeks of treatment. RESULTS: At the 9th week, no patients showed clinically evident neuropathy in the GSH arm, whereas 16 patients in the placebo arm did. After the 15th week, four of 24 assessable patients in the GSH arm suffered from neurotoxicity versus 16 of 18 in the placebo arm (P = .0001). In confirmation of this neuroprotective effect, the neurophisiologic investigations, based on the evaluation of the median, ulnar, and sural sensory nerve conduction, showed a statistically significant reduction of these values in the placebo arm but not in the GSH arm, above all considering potential amplitude. In this trial, GSH also reduced hemotransfusion requirements (32 v 62 hemotransfusions) and treatment delay (55 v 94 weeks). The response rate was 76% (20% complete response) in the GSH group and 52% (12% complete response) in the placebo arm, confirming preliminary reports about the lack of reduction in activity of cytotoxic drugs induced by GSH. CONCLUSION: This study provides evidence that GSH is a promising and effective new drug for the prevention of CDDP-induced neuropathy, and that it does not reduce the clinical activity of chemotherapeutic drugs.

Johnston CS, Meyer CG, Srilakshmi JC. Vitamin C elevates red blood cell glutathione in healthy adults. Am J Clin Nutr. 1993 Jul;58(1):103-105.
Abstract: We examined the effect of supplemental ascorbic acid on red blood cell glutathione. Subjects consumed self-selected vitamin C-restricted diets, and, under double-blind conditions, ingested placebo daily for week 1 (baseline), 500 mg L-ascorbate/d for weeks 2-3, 2000 mg L-ascorbate/d for weeks 4-5, and placebo daily for week 6 (withdraw). Mean red blood cell glutathione rose nearly 50% (P < 0.05) after the 500-mg period compared with baseline, and the changes from baseline for individual subjects ranged from +8% to +84%. However, the increases in plasma vitamin C and red blood cell glutathione were not correlated (r = 0.22). At the 2000-mg dosage, mean red blood cell glutathione was not significantly different from the value obtained at the 500-mg dosage. After the placebo-controlled withdraw period, red blood cell glutathione did not differ from baseline. These data indicate that vitamin C supplementation (500 mg/d) maintains reduced glutathione concentrations in blood and improves the overall antioxidant protection capacity of blood.

Jones MM, Basinger MA, Holscher MA. Relative effectiveness of some compounds for the control of cisplatin-induced nephrotoxicity. Toxicology 1991;68(3):227-247.
Abstract: Several procedures which have been reported as effective for the control of cisplatin induced nephrotoxicity were compared in the Sprague-Dawley rat using the same dose of cisplatin. The treatments examined were based on the use of sodium thiosulfate, sodium diethyldithiocarbamate (DDTC), glutathione (GSH), sodium N-methyl-D-glucamine dithiocarbamate (NaG) and S-2-(3-aminopropylamino)ethylphosphorothioic acid (WR-2721). The differences in the effectiveness of the procedures were assessed using BUN and serum creatinine values, histopathological examination, body weight changes, and renal platinum levels as indices. The effect of such treatments on the antineoplastic activity of cisplatin were examined with both the Walker 256 carcinosarcoma in the rat and the L1210 murine leukemia in mice. Under the conditions used, GSH was found to be more effective than the other nucleophiles in protecting against the nephrotoxicity of cisplatin while providing the least amount of interference with the antitumor activity as measured against the Walker 256 carcinosarcoma and the L1210 murine leukemia. Simultaneous i.v. administration of cisplatin and any of the sulfur-containing nucleophiles leads to a significant protection against the nephrotoxicity but reduced the anti-neoplastic activity of cisplatin when measured against the Walker 256 carcinosarcoma.

Jurima-Romet M, Abbott FS, Tang W, Huang HS, Whitehouse LW. Cytotoxicity of unsaturated metabolites of valproic acid and protection by vitamins C and E in glutathione-depleted rat hepatocytes. Toxicology 1996 Aug 1;112(1):69-85.
Abstract: Valproic acid (VPA) and the unsaturated metabolites, 2-ene VPA and (E)-2,(Z)-3'-diene VPA, demonstrated dose-dependent cytotoxicity in primary cultures of rat hepatocytes, as evaluated by lactate dehydrogenase (LDH) leakage. Cellular glutathione (GSH) was depleted by adding buthionine sulfoximine (BSO) to the culture medium. Induction of cytochrome P450 by pretreatment of rats with phenobarbital or pregnenolone-16 alpha-carbonitrile enhanced the cytotoxicity of parent VPA in BSO-treated hepatocytes. The cytotoxicity of 4-ene VPA was apparent in BSO-treated hepatocytes with detectable loss of cell viability at 1 microM of added 4-ene VPA. Depletion of cellular GSH also increased the cytotoxicities of 2-ene VPA and (E)-2,(Z)-3'-diene VPA. The cytotoxicity of 2-ene VPA was comparable to or higher than that of VPA, producing loss of viability at concentrations > or = 5 mM. Time-course evaluation of hepatocyte response to 4-ene VPA in the GSH-depleted state revealed a delayed cytotoxicity with no effect during the first 12 h of exposure followed by a pronounced toxicity between 12 and 14 h. Two major GSH conjugates of 4-ene VPA metabolites, namely 5-GS-4-hydroxy VPA lactone and 5-GS-3-ene VPA, were detected in 4-ene VPA treated hepatocytes. Consistent with this finding, a 50% decrease in cellular GSH levels was observed following 4-ene VPA treatment. Under similar conditions, neither toxicity nor the GSH conjugated metabolite were detected in cells treated with the alpha-fluorinated 4-ene VPA analogue (alpha-F-4-ene VPA). The antioxidants, vitamin C and vitamin E, demonstrated a cytoprotective effect against 4-ene VPA-induced injury in GSH-depleted hepatocytes. These results are in support of hepatocellular bioactivation of VPA via 4-ene VPA to highly reactive species, which are detoxified by GSH. The susceptibility of hepatocytes to VPA metabolite-mediated cytotoxicity depends on cellular GSH homeostasis.

Kurekci AE, Alpay F, Tanindi S, Gokcay E, Ozcan O, Akin R, Isimer A, Sayal A. Plasma trace element, plasma glutathione peroxidase, and superoxide dismutase levels in epileptic children receiving antiepileptic drug therapy. Epilepsia 1995 Jun;36(6):600-604.
Abstract: Some antiepileptic drugs (AEDs) may alter trace element metabolism and free radical scavenging enzyme activities in humans and experimental animals. We investigated the effect of long-term AED therapy on copper (Cu), zinc (Zn), manganese (Mn), selenium (Se), magnesium (Mg), glutathione peroxidase (GSH-PX), and superoxide dismutase (SOD) in the plasma in children with epilepsy. During treatment with valproate (VPA) or carbamazepine (CBZ) monotherapy plasma Cu, Zn, Mn, Se, and Mg concentrations of patients were not statistically different from those of control subjects. The level of serum VPA weakly correlated with the increase in plasma Zn level. Recent studies suggest that membrane lipid peroxidation may be causally involved in some forms of epilepsies, and the decreased free radical scavenging enzyme activity is believed to cause the increased risk of an idiosyncratic drug reaction encountered in the management of epilepsy. Because GSH-PX and SOD are the most important members of antioxidant defense mechanisms, we quantitated the activities of these enzymes in plasma of children with epilepsy receiving VPA or CBZ. Only plasma GSH-PX activities in VPA group were higher than those of the control group, and the difference was statistically significant

Rabinovic AD, Hastings TG. Role of endogenous glutathione in the oxidation of dopamine. J Neurochem. 1998 Nov;71(5):2071-2078.
Abstract: Intrastriatal injection of dopamine causes the selective degeneration of tyrosine hydroxylase-containing terminals and an increase in content of cysteinyl-catechols, an index of dopamine oxidation. Both of these effects can be attenuated by coadministration of antioxidants such as glutathione. Therefore, we investigated the effects of decreased endogenous glutathione on the neurotoxic potential of dopamine. We observed that pretreatment with either L-buthionine sulfoximine, a specific inhibitor of glutathione synthesis, or diethyl maleate, which forms adducts with glutathione, caused significant decreases in endogenous glutathione levels at the time of dopamine injection. Pretreatment with L-buthionine sulfoximine potentiated the formation of protein cysteinyl-dopamine after intrastriatal injection of 1.0 micromol of dopamine. We also observed that intrastriatal injection of 1.0 micromol of dopamine decreased striatal glutathione content in all pretreatment conditions. However, injection of a low dose (0.05 micromol of dopamine) caused a decrease in striatal glutathione levels only in the L-buthionine sulfoximine-pretreated rats. Diethyl maleate pretreatment was not effective in potentiating either cysteinyl-catechol formation or glutathione loss after dopamine injection. We conclude that dopamine contributes to cellular oxidative stress and that this can be exacerbated, or at least unmasked, if glutathione synthesis is compromised.

Shivakumar BR, Ravindranath V. Shivakumar BR, et al. Oxidative stress and thiol modification induced by chronic administration of haloperidol. J Pharmacol Exp Ther. 1993 Jun;265(3):1137-1141.
Abstract: Haloperidol, a widely used neuroleptic, acts through blockade of dopamine receptors leading to increased turnover of dopamine. Increased turnover of dopamine could lead to excessive production of hydrogen peroxide and, thus, generate oxidative stress. The effect of chronic administration of haloperidol on glutathione (GSH)-protein thiol homeostasis and lipid peroxidation was examined in rat brain regions. The oxidized GSH levels increased significantly, though not substantially, in cortex (CT, 15%), striatum (ST, 28%) and midbrain (MB, 27%). Maximal decreases in GSH levels were noted in CT (23%), ST (28%) and MB (20%) after 1 month of haloperidol administration. The GSH levels recovered thereafter, and after 6 months of haloperidol treatment, the GSH levels were not significantly different from control in ST and MB. The depleted GSH was recovered essentially as protein-GSH mixed disulfide with a concomitant decrease in the protein thiol concentration in all the three regions of the brain. The increase in oxidized GSH concentration represented only 1.8, 2.0 and 3.5% of the depleted GSH in the CT, ST and MB after 1 month of haloperidol administration. The concentration of thiobarbituric acid-reactive products increased significantly up to 3 months of haloperidol treatment, but at the end of 6 months, the levels were substantially decreased. The present study demonstrates that haloperidol administration for 1 month results in significant oxidative stress in CT, ST and MB regions of the brain, as demonstrated by alterations in GSH-protein thiol homeostasis and increased lipid peroxidation products. However, after prolonged administration of haloperidol for 6 months, the GSH-protein thiol homeostasis is restored to a large extent, concomitant with the decrease in the concentration of lipid peroxidation products. Administration of haloperidol leads to development of tolerance (supersensitivity of the dopamine autoreceptors) to neuroleptics, which is associated with decreased turnover of dopamine; this may result in overcoming the oxidative stress generated initially due to increased dopamine turnover.

Smyth JF, Bowman A, Perren T, Wilkinson P, Prescott RJ, Quinn KJ, Tedeschi M. Glutathione reduces the toxicity and improves quality of life of women diagnosed with ovarian cancer treated with cisplatin: Results of a double-blind, randomised trial. Ann Oncol 1997 Jun;8(6):569-573.
Abstract: BACKGROUND: Early clinical trials have suggested that glutathione (GSH) offers protection from the toxic effects of cisplatin. PATIENTS AND METHODS: One hundred fifty-one patients with ovarian cancer (stage I-IV) were evaluated in a clinical trial of cisplatin (CDDP) +/- glutathione (GSH). The objective was to determine whether GSH would enhance the feasibility of giving six cycles of CDDP at 100 mg/m2 without dose reduction due to toxicity. RESULTS: When considering the proportion of patients receiving six courses of CDDP at any dose, GSH produced a significant advantage over control--58% versus 39%, (P = 0.04). For these patients there was a significant difference between the reduction in creatinine clearance for GSH treated patients compared with control--74% versus 62% (P = 0.006). Quality of life scores demonstrated that for patients receiving GSH there was a statistically significant improvement in depression, emesis, peripheral neurotoxicity, hair loss, shortness of breath and difficulty concentrating. As an indication of overall activity, these patients were statistically significantly more able to undertake housekeeping and shopping. Clinically assessed response to treatment demonstrated a trend towards a better outcome in the GSH group (73% versus 62%) but this was not statistically significant (P = 0.25). CONCLUSIONS: The results demonstrate that adding GSH to CDDP allows more cycles of CDDP treatment to be administered because less toxicity is observed and the patient's quality of life is improved.

Werbach MR. Foundations of Nutritional Medicine. Tarzana, CA: Third Line Press, 1997. (Review).

Witschi A, Reddy S, Stofer B, Lauterburg BH. The systemic availability of oral glutathione. Eur J Clin Pharmacol. 1992;43(6):667-669.
Abstract: When the plasma glutathione concentration is low, such as in patients with HIV infection, alcoholics, and patients with cirrhosis, increasing the availability of circulating glutathione by oral administration might be of therapeutic benefit. To assess the feasibility of supplementing oral glutathione we have determined the systemic availability of glutathione in 7 healthy volunteers. The basal concentrations of glutathione, cysteine, and glutamate in plasma were 6.2, 8.3, and 54 mumol.l-1 respectively. During the 270 min after the administration of glutathione in a dose of 0.15 mmol.kg-1 the concentrations of glutathione, cysteine, and glutamate in plasma did not increase significantly, suggesting that the systemic availability of glutathione is negligible in man. Because of hydrolysis of glutathione by intestinal and hepatic gamma-glutamyltransferase, dietary glutathione is not a major determinant of circulating glutathione, and it is not possible to increase circulating glutathione to a clinically beneficial extent by the oral administration of a single dose of 3 g of glutathione.