A not even terribly high dose of curcumin – the principal bioactive ingredient in turmeric powder – causes a steep rise in the amount of testosterone in the blood of male rats. Researchers from Redeemer’s University in Nigeria wrote about it in the Journal of Steroid Biochemistry and Molecular Biology.
The Nigerians studied the joint effect of gallic acid – a substance present in tea and grapes – and curcumin on the testes. The structural formula of gallic acid is shown here. Gallic acid has a wide range of protective properties, but in high quantities it turns out to be an oxidant.
The researchers wondered whether high concentrations of gallic acid reduce the production of sperm and testosterone as a result of pro-oxidant effects – and if so, whether curcumin, which has a convincing antioxidant effect, can counteract these effects.
The Nigerians performed experiments with four groups of young male rats. For 30 days the rats were given either no active ingredients [Control], 100 mg gallic acid per kg bodyweight, 100 mg curcumin per kg bodyweight, or 100 mg gallic acid + 100 mg curcumin per kg bodyweight.
The researchers gave the animals the substances, mixed with corn oil, orally.
At the end of the 30 days, the sperm quality of the gallic-acid group had deteriorated, but that of the curcumin group had improved. In the rats that had been given both substances, the sperm quality had also improved, but less than it had in the curcumin group.
DSP = Daily Sperm Production.
The testosterone concentration in the blood of the gallic-acid group was 32 percent lower than in the control group. In the curcumin group the testosterone concentration in the blood was 257 percent higher than in the control group and in the combination group it was 184 percent higher.
The raised testosterone level was the consequence of heightened activity of enzymes such as 3-beta-HSD and 17-beta-HSD in the testes. These enzymes are involved in the biosynthesis of testosterone.
In the testes gallic acid reduced the concentration of glutathione [GSH], glutathione peroxidase [GSH-Px], catalase [CAT] and superoxide dismutase [SOD] compared with the control group. These are endogenous antioxidants.
Curcumin had precisely the opposite effect, and also reduced the concentration of malondialdehyde [MDA] [Structural formula shown on the right]. Malondialdehyde is formed when free radicals damage unsaturated fatty acids in membranes.
The researchers suspect that curcumin deactivates free radicals in the testes and that this helps the testes to function better.
“Based on our results, curcumin might be used as an alternative drug for the treatment of male infertility problems”, the researchers write. “However, the exact mechanism of action and dose analysis need to be further investigated, and whether adding dietary curcumin will improve men’s chances of fathering children remains to be determined.”
If you consult tables and start to calculate, you’ll see that it’s difficult to ingest the kind amounts of ‘pure’ gallic acid, just from food, that would cause damage to your testes. But by taking supplements it’s not so difficult to take in the amount of curcumin that would improve your testes functioning.
The human equivalent of the dose that the Nigerians tried out would be between 1 and 1.5 g curcumin per day. There are supplements on the market that would give you that amount in just a couple of capsules.
Combined administration of curcumin and gallic acid inhibits gallic acid-induced suppression of steroidogenesis, sperm output, antioxidant defenses and inflammatory responsive genes.
In this study, we investigated the effects of administration of gallic acid (Gal) with or without curcumin (Cur) on the sperm output, steroid level and antioxidant defenses in rat testis in vivo and the expression of inflammatory responsive genes in vitro. Male Wistar rats were divided randomly into four groups and given oral Gal (100mg/kg/day) and Cur (100mg/kg/day) alone or in combination for four weeks. The sperm quality was impaired following Gal treatment, while Cur prevented this and also improved the sperm count as well as the efficiency of sperm production (DSP/gm testis). The inhibitory effects of Gal on plasma testosterone level, glutathione levels, activities of glutathione peroxidase, catalase, superoxide dismutase and steroidogenic enzymes, 3?-hydroxysteroid dehydrogenase (3?-HSD) and 17?-HSD in the rat testis was blocked by Cur. Interestingly, the level of testosterone and the activities of the steroidogenic enzymes were significantly increased after treatment with Cur alone. Malondialdehyde concentration was unchanged following Gal treatment, while a significant decrease in malondialdehyde level was observed following treatment with Cur alone or in combination with Gal. We further analyzed the effects of Cur and Gal (25-100 ?M) on the 93RS2 Sertoli cell-lines and observed that Cur blocked the Gal-induced suppression of inflammatory mediators such as TNF-? and IL-6, while Gal blocked the suppressive effect of Cur on IL-1? expression. Furthermore, the stimulatory or inhibitory effects of Gal on the expressions Tgf-?1 and CD-14 was concentration-dependent and could be blocked by Cur. When cultures of primary Sertoli cells were exposed to both Cur and Gal for 24h, p-JNK/SAPK expression remain stable, whereas Gal-induced p-p65 (NF-?B) expression and I?B? degradation was seen to be blocked by Cur but not Gal-induced expression of pERK1/2. Overall, Cur has stimulatory reproductive effects and could protect the testis from the toxic effects of Gal by mechanisms that could not be explained by its effects on the expressions of inflammatory cytokines but by its anti-oxidant properties.
Copyright © 2014 Elsevier Ltd. All rights reserved.
PMID: 24565563 [PubMed – indexed for MEDLINE]