Supplements featuring yohimbe have a checkered history in that the ingredient features most prominently in the sexual enhancement space and sports nutrition spaces. These are categories of great concern for FDA in that they are rife with shady claims and products in this space all too often feature the inclusion of undeclared active pharmaceutical ingredients.
Yohimbe extract is derived from the bark of an evergreen tree species native to Central Africa. The ingredient has a history of traditional use as an aphrodisiac and to treat erectile dysfunction. The active chemical is yohimbine HCl, and is available in a synthesized form. The synthetic form has sometimes been used as a drug for erectile dysfunction in the past, with some side effects including nervousness, irritability, insomnia, headache and skin flushing.
Sample cleanup
A problem with yohimbe products up to now has been that is has been time consuming and expensive to prepare samples for analysis, Neal-Kababick said. And the things the chemist is looking for are difficult to differentiate, so up to now it has been very difficult to find if a product was truly of a botanical source or was a synthetic.
The synthetic compound is restricted in Australia and is monographed as a drug in the US Pharmacopoeia. So finding a way to quickly and cheaply analyze samples was needed, Neal-Kababick said, and the new method achieves that. Yohimbe is often contained in multiple-ingredient sports formulations, making sample preparation a nightmare.
“There wasn’t a good eco-friendly, quick method where you could rapidly prepare samples from products that are complex like these sports powders and run them at low levels,” Neal-Kababick told NutraIngredients-USA.
“This is an extremely sensitive method. We can determine if this material is synthetic yohimbine hydrochloride or if it is really yohimbe bark extract. A lot of these other alkaloids that might be in the bark extract have similar mass and similar structures and we were able to separate these and detect them,” he said.
Possible safety issue
Yohimbe has never been a blockbuster ingredient and thus has flown under the radar for a number of years. A safety assessment by EFSA in 2011 came up as inconclusive, though that didn’t stop Dr Adam Carey of the European Specialist Sports Nutrition Alliance (ESSNA) to advocate for a proactive ban on the products. The new method developed at Neal-Kababick’s lab could help to further inform that debate.
“The first thing is to make sure you have the material labeled in compliance with GMP requirements. If the synthetic is in there it should be on the label,” Neal-Kababick said.
But further, he said recent results from his lab indicate that there is poor quality control among some yohimbe-containing products and even though there have been few, if any, adverse events associated with this ingredient, that raises a potential red flag.
“We have found yohimbe HCl in come products where it didn’t say it was in there. And we tested a product where is was yohimbe bark extract, but it was way beyond label claim. The expected yohimbine content was 8,000 ug/g and we found 29,000. If you combine yohimbine with caffeine you have the potential for some adverse events,” Neal-Kababicks said.
While not ethically defensible, some of the issue with quality control in the past could stem from the difficulty and expense of doing the tests. Neal-Kababick said the new method means cost will no longer be an excuse for less-than-adequate finished product testing.
“If you can get that prep and testing down to a much faster process it is financially achievable. You can prep and test dozens of samples in the same time it took to run one sample in the past,” he said.
Source: Journal of AOAC International
Volume 98, Number 2, Pages 300-335
Authors: Lucas D, Neal-Kababick J, Zweigenbaum J