Ursolic Acid: Another Anabolic Failure? by Jerry Brainum 11/20

 

 

I first wrote about ursolic acid in the May, 2015 issue of Applied Metabolics. That article was based on a human study that found significant anabolic effects following the ingestion of ursolic acid. Ursolic acid is a natural compound found in a number of sources, such as rosemary (the herb, not your friend Rosemary); basil; oregano; eucalyptus; coffee; and probably the richest source, apple peels. If you eat the fruit of an apple and discard the peel, you are throwing away the entire ursolic acid content of the apple. Ursolic acid attracted the attention of scientists when studies showed that it offered a number of important health benefits. These include anti-inflammatory activity; antioxidant effects; cancer prevention; increased thermogenesis, which promotes body fat loss; and from the perspective of those engaged in bodybuilding, fitness, or sports, prevention of muscle atrophy and increased muscle protein synthesis. Sounds like something anyone would want to ingest. But there are some caveats to consider about ursolic acid. For one. nearly all of the studies that have found these wonderful health benefits involved animal research. I don't often write about animal research because if anything, it's just preliminary research that may or may not be applicable to human physiology. In many cases, what helps or hurts animals will not produce the same effects in humans. But this doesn't mean that the same effects cannot occur in humans, either. But that would require specific studies involving human subjects and must also include a tight study design, such as a randomized, placebo-controlled, double-blind study.

Ursolic acid is thought to promote thermogenesis, which involves the conversion of calories into heat, by activating a protein called uncoupling protein-1 (UCP1). This protein exists in the mitochondria of cells and is also activated by thyroid hormones, as well as the drug DNP. But a human study published shortly before I wrote my article about ursolic acid also found that the substance promoted the release of a myokine called irisin. Myokines are compounds released by a muscle that exert biological activity in a manner similar to hormones. Among the effects of irisin is the ability to convert white adipose fat tissue, the most common kind, into beige and brown adipose tissue or BAT. BAT is a thermogenic tissue that contains UCP1 and the more BAT you have, the greater the ability to oxidize fat even at rest. Another way that ursolic acid helps promote fat loss is by promoting the activity of AMPK, an energy sensor in the muscle that when activated allows greater fat burning in muscle. AMPK is also activated when ATP, the primary source of cellular energy, is depleted, and this could happen if muscle and liver glycogen stores are also depleted, as would occur with a very low carbohydrate intake.

Besides promoting increased anabolic effects in muscle, ursolic acid also works to prevent muscle breakdown . . .