Studies on the metabolism and toxicology of emerging capsinoids.

INTRODUCTION: Capsinoids are nonpungent compounds that are found in almost all pungent peppers and are abundant in the sweet pepper cultivar CH-19 Sweet. Since the discovery of capsinoids 13 years ago, various physiological effects of these compounds - especially reduction of visceral fat - have been observed both in rodents and humans. Recently, capsules containing capsinoids have become commercially available and comprehensive studies have been performed on the metabolism and toxicity of capsinoids. AREAS COVERED: This article reviews all the literature from 1998 to date providing details on the nature and physiological effects of capsinoids. In addition to this, the article also looks at their metabolism as well as their acute and chronic toxicity including their genotoxicity and teratology. EXPERT OPINION: Capsinoids are the most promising compounds among all known transient receptor potential vanilloid 1 agonists. The physiological activities of capsinoids are similar to those of capsaicin, the most pungent food component of red pepper, but appear to be much safer to use as a therapeutic compound. That said, there is still a need for further research into the capsinoid mechanism of action before it can be 'green-lighted' for therapeutic use.