One kilogram of plant material contains anywhere between 10 and 100 micrograms of a group of compounds biochemists call brassinosteroids. These are oxysteroles and they function as growth hormones in plants. Cell- and animal studies have shown that the brassinosteroid 28-homobrassinolide [structural formula on the right] at least has an anabolic effect on lab rats. Biochemists at Pondicherry University in India will soon publish the results of an animal study in which the same 28-homobrassinolide also boosts testosterone synthesis.
Plants are bursting with substances that are interesting for athletes.
Ursolic acid for example, a steroid found in apple peel. Or ecdysterone, a steroid that is found in spinach. Or brassinosteroids, a group of compounds found in in all fast-growing and young plant tissue, like seeds, beans and beansprouts.
How they got the idea, the Indians don’t divulge, but they obviously wondered whether 28-homobrassinolide boosted the production of testosterone in healthy and diabetic male rats. They gave their lab animals 33 micrograms of 28-homobrassinolide per kg bodyweight every day for 15 days. For a man weighing 80 kg that amounts to 4.3 mg per day. [No idea whether this is a safe dose, Ed.] The researchers dissolved the brassinosteroid in alcohol.
28-Homobrassinolide boosted the activity of 3beta-hydroxysteroid dehydrogenase and 17beta-hydroxy steroid dehydrogenase in the rats’ testes. These enzymes are involved in the production of testosterone. Below right you can see that 28-brassinolide raised the concentration of the androgen-binding protein [ABP] and steroidogenic acute regulatory protein [StAR].
ABP is virtually the same as SHBG. ABP transports testosterone to the seminal vesicles, where the hormone stimulates the production of sperm. The StAR protein plays a key role in the conversion of cholesterol into testosterone.
In the figure above right you can see that 28-homobrassinolide boosted the concentration of testosterone in the rats’ testes.
The researchers also discovered that the brassinosteroid boosted the activity of endogenous antioxidant enzymes like superoxide dismutase, catalase and GSH, and reduced the peroxidation of fats, particularly in the testes of the rats with diabetes.
“The brassinosteroid plant hormone isoform 28-homobrassinolide is an inducer of testosterone production in normal and diabetic rat testicular cells”, the researchers conclude. “Results of our study indicate a possible role for endogenous oxysterols in animal cells in the regulation of male reproductive function, since 28-homobrassinolide as a plant oxysterol is capable of eliciting the observed biological responses in rat testicular function.”