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Definition: "An ergogenic aid is any substance or phenomenon that enhances performance "

25.09.2011

Ginkgo's role in the chemistry of lust still elusive

Supplements containing extracts of the ancient Ginkgo biloba boost men's libido. At least they do if men react in the same way as the rats in the study that Taiwanese researchers published in Neuroscience Letters.

Ginkgo
Ginkgo biloba trees were growing on this planet when dinosaurs ruled the earth. Like the dinosaurs, all relatives of the ginkgo died out millions of years ago. So Ginkgo biloba is a living fossil – and it's all because the tree produces special compounds that protect it from disease and insects, and which are not found in any other plants.

And it's because of these same compounds that the tree is now experiencing its greatest success in its entire history. Humans spread the tree, which until recently was only still found in China, over the whole world after herbal healers [and later scientists] discovered that ginkgo extracts have many health-promoting effects. The same interesting compounds that have protected the ginkgo for millions of years against disease also offer protection against stress, delay processes of aging, keep bones strong and extend life expectancy. At least, they do in animal studies.

Ginkgo & sex
The Taiwanese have been studying the effects of Ginkgo biloba on sexual behaviour for a few years. They give the standardised ginkgo extract EGb 761 from the German Dr Willmar Schwabe Pharmaceuticals to male rats, which, as a result, have more erections and copulate more frequently with females. We've written about this research before. The Taiwanese are studying brain tissue in order to better understand the neurological processes that are involved in an increase in libido.

The theory that the Taiwanese use for this is the brainchild of the American researcher Elaine Hull. [PubMed] Hull has spent several decades studying processes in the medial preoptic area [part of the hypothalamus] in rats. Sexual appetite increases in this area of the brain when dopamine concentrations rise. [Horm Behav. 2005 May; 47(5): 513-22.] The figure below summarises how this is thought to happen.

E2 = estradiol; nNOS = neuronal nitric oxide synthase [an enzyme that removes an NO molecule from L-arginine]; DA = dopamine; MPOA = medial preoptic area.

The Taiwanese reported in an earlier publication that Ginkgo biloba boosted the concentration of dopamine in the medial preoptic area. [Neuroscience. 2011 Aug 25; 189:199-206.] And now they claim that ginkgo does the same in other parts of the brain. [Psychopharmacology (Berl). 2010 Jul; 210(4): 585-90.]

More sex
In the study we're talking about here, the Taiwanese demonstrated again that male rats have sex more often with females after a two-week course of 50 mg ginkgo extract per kg bodyweight. The rats that were given the supplement had twice as many erections as the control group.

The Taiwanese had expected Ginkgo biloba to boost the synthesis of the enzyme nNOS. But as you can see in the graph above, this was not the case. So how ginkgo boosts the dopamine concentration in the sex centres of the brain remains a mystery for now.

Sponsor
The researchers were not funded by the supplements industry, but by the Taiwanese government.

Source:
Neurosci Lett. 2011 Aug 18;500(3):182-6.

More:
Animal study: ginkgo is prolactin inhibitor 17.08.2008