Capsinoids, which include capsiate, dihydrocapsiate, and nordihydrocapsiate, are substances naturally present in

chili pepper Chili peppers (also chile, chile pepper, chilli pepper, or chilli), from Nahuatl '' chīlli'' (), are varieties of the berry-fruit of plants from the genus ''Capsicum'', which are members of the nightshade family Solanaceae, cultivated for ...

s. Although they are structurally similar to

capsaicin Capsaicin (8-methyl-''N''-vanillyl-6-nonenamide) ( or ) is an active component of chili peppers, which are plants belonging to the genus ''Capsicum''. It is a chemical irritant for mammals, including humans, and produces a sensation of burnin ...

, the substance that causes pungency in hot peppers, they largely lack that characteristic. Capsinoids have an estimated "hot taste threshold" which is about 1/1000 that of capsaicin. Capsinoids were not reported in the scientific literature until 1989,Yazawa S, et al., Content of capsaicinoids and capsaicinoid-like substances in fruit of pepper (''Capsicum annuum'' L.) hybrids made with “CH-19 Sweet as a parent. J Jpn Soc Hortic Sci58:601-607, 1989. when biologists first isolated them in a unique variety of chili peppers, CH-19 Sweet, which does not contain capsaicin. Capsinoids include capsiate, dihydrocapsiate, and nordihydrocapsiate.Kobata, K., Todo, T., Yazawa, S., Iwi, K. and Watabe, T. (1998) Novel capsaicinoid-like substances, capsiate and dihydrocapsiate, from the fruits of a nonpungent cultivar, CH-19 sweet, of pepper (Capsicum annuum L.). Journal of Agriculture and Food Chemistry 46:1695-1697.Kobata, K., Sutoh, K., Todo, T., Yazawa, S., Iwai, K. and Watanabe, T. (1999) Nordihydrocapsiate, a new capsinoid from the fruits of a nonpungent pepper, Capsicum annuum. Journal of Natural Products. 62:335-336.Yazawa, S., Yoneda, H., Hosokawa, M., Fushiki, T. and Watanabe, T. (2004) Novel capsaicinoid like substances in the fruits of new non-pungent cultivar CH/19 sweet of pepper (Capsicum annuum). Capsicum and Eggplant Newsletter 23:17-20. Many health effects have been ascribed to capsaicin and capsinoids, both anecdotally and through scientific study, including anticancer, anti-inflammatory, and analgesic activities, and weight management.Antonio Macho, Concepción Lucena, Rocio Sancho, Nives Daddario, Alberto Minassi, Eduardo Muñoz, Giovanni Appendino. "Non-pungent Capsaicinoids from Sweet Pepper Synthesis and Evaluation of the Chemopreventive and Anticancer Potential." Eur. J. Nutr. 42 (2003): 2-9.Rocío Sancho, Concepción Lucena, Antonio Macho, Marco A. Calzado, Magdalena Blanco-Molina, Alberto Minassi, Giovanni Appendino and Eduardo Muñoz. "Immunosuppressive Activity of Capsaicinoids: Capsiate Derived from Sweet Peppers Inhibits NF-kappaB Activation and is a Potent Anti-inflammatory Compound in Vivo." Eur. J. Immunol. 32 (2002): 1753-1763.He G.-J. et al., European Journal of Medicinal Chemistry 44: 3345-3349, 2009Kawabata F. et al., Biosci Biotechnol Biochem 70:2824-2835, 2006.Sheldon Handler Ph.D., M.D.; David Rorvik: PDR for Nutritional Supplements Second Edition. Thomas Reuters; 2008.

Structure

Structural differences between capsaicin and members of the capsinoid family of compounds are illustrated below. Capsinoids have an ester bond in their structures, as compared with the amide bond characteristic of capsaicin. Capsinoids structure

Mechanisms of action: capsaicin vs. capsinoids

It is anecdotally said that hot peppers help people in the tropics “cool off.” This theory is consistent with the peripheral vasodilatory effect of capsaicin that has been shown to lower skin temperature in humans exposed to a hot environment.Nelson A.G. et al., Wilderness Environ Med;11:152-6, Fall 2000. Capsaicin feels hot in the mouth because it activates sensory receptors on the tongue otherwise used to detect thermal heat.Szallasi, A. and Blumberg, P.M., 1999. Vanilloid (Capsaicin) receptors and mechanisms. Pharmacology Reviews 51, 159–212. This receptor is called Transient Receptor Potential Vanilloid 1 (

TRPV1 The transient receptor potential cation channel subfamily V member 1 (TrpV1), also known as the capsaicin receptor and the vanilloid receptor 1, is a protein that, in humans, is encoded by the ''TRPV1'' gene. It was the first isolated member of th ...

). TRPV1 receptors are also located in the gut and in other organs.Nagy L. et al., Eur J Pharmacol 500: 351-369, 2004 Stimulation of TRPV1 receptors is known to bring about activation of the

sympathetic nervous system The sympathetic nervous system (SNS) is one of the three divisions of the autonomic nervous system, the others being the parasympathetic nervous system and the enteric nervous system. The enteric nervous system is sometimes considered part of t ...

(SNS).Iwai K. et al. Roles as metabolic regulators for the non-nutrients capsaicin and capsiate, supplemented to diet. Proc. Japan Acad., 79B (7) 207-212 (2003) Capsaicin has been shown to increase fat burning in humans and animals through stimulation of the SNS.Kawada T. et al., J Nutr 116:1272-1278, 1986.Kawada T. et al., Proc Soc Exp Biol Med 183:250-256, 1986.Yoshioka M. et al., British Journal of Nutrition 80: 503-510, 1998. Like capsaicin, capsinoids activate TRPV1 receptors,Iida T. et al., Neuropharmacol 44:958-967, 2003. although they are not hot in the mouth. Capsinoids cannot reach the TRPV1 oral cavity receptors, located slightly below the surface in the mouth, because of structural differences from capsaicin. On the other hand, both capsaicin and capsinoids activate TRPV1 receptors in the same manner. Research has indicated that the TRPV1 receptors in the gut are important for the metabolic effects of capsaicin and capsinoids.Ohnuki K. et al., J Nutr Sci Vitaminol 47:295-298, 2001. Both energy metabolism Snitker S. et al. Effects of novel capsinoids treatment on fatness and energy metabolism in humans: possible pharmacogenetic implications. Am, J. Clin. Nutr. 89 45-50 (2009)Inoue N. et al., Biosci Biotechnol Biochem 71: 380-389, 2007. and body temperature Ohnuki K. et al., Biosci Biotechnol Biochem 65:2033-2036, 2001(a).Sachiko Hachiya, Fuminori Kawabata, Koichiro Ohnuki, Naohiko Inoue, Hirotsugu Yoneda, Susumu Yazawa and Tohru Fushiki. "Effects of CH-19 Sweet, a Non-Pungent Cultivar of Red Pepper, on Sympathetic Nervous Activity, Body Temperature, Heart Rate, and Blood Pressure in Humans." Biosci. Biotechnol. Biochem. 71 (2007): 671-676. increases are observed in humans following extracted capsinoids or CH-19 Sweet administration. Animal studies also demonstrate these increases, as well as suppressed in body fat accumulation following capsinoids intake.Ohnuki K. et al., Biosci Biotechnol Biochem 65:2735-2740, 2001. The exact mechanisms and the relative importance of each remain under investigation, as are the effects of capsinoids on appetite and satiation.Reinbach H.C. et al., Clinical Nutrition 28: 260-265, 2009

Safety testing

Purified extracts of the sweet chili pepper containing capsinoids have been extensively studied through rigorous safety tests, including evaluation of chronic toxicity, reproduction, genotoxicity, and teratology in animals, single oral administration and pharmacokinetics in humans.Kodama, T., E. Watanabe, T. Masuyama, S. Tsubuku, A. Otabe, M. Mochizuki, B.K. Bernard. "Studies of the Toxicological Potential of Capsinoids: II. A 26-Week Daily Gavage Dosing Toxicity Study of CH-19 Sweet Extract in Rats", Int. J. Toxicol. 27 (Suppl. 3) (2008): 11-28.Kodama, T., E. Watanabe, T. Masuyama, S. Tsubuku, A. Otabe, Y. Katsumata, B.K. Bernard."Studies of the Toxicological Potential of Capsinoids: III. A Two-Generation Reproduction Study of CH-19 Sweet Extract in Rats", Int. J. Toxicol. 27 (Suppl. 3) (2008): 29-40.Watanabe, E., T. Kodama, T. Masuyama, S. Tsubuku, A. Otabe, M. Mochizuki, M. Nakajima, S. Masumori, B.K. Bernard. "Studies of the Toxicological Potential of Capsinoids: I. Single-Dose Toxicity Study and Genotoxicity Studies of CH-19 Sweet Extract", Int. J. Toxicol. 27 (Suppl. 3) (2008): 1-10.Bernard, B.K., E. Watanabe, T. Kodama, S. Tsubuku, A. Otabe, Y. Katsumata, T. Matsuoka, T. Masuyama."Studies of the Toxicological Potential of Capsinoids: IV. Teratology Studies of CH-19 Sweet Extract in Rats and Rabbits", Int. J. Toxicol. 27 (Suppl. 3) (2008): 41-58.Bernard, B.K., S. Tsubuku, T. Kayahara, K. Maeda, M. Hamada, T. Nakamura, Y. Shirai, A. Nakayama, S. Ueno, R. Mihara."Studies of the Toxicological Potential of Capsinoids: X Safety Assessment and Pharmacokinetics of Capsinoids in Healthy Male Volunteers after a Single Oral Ingestion of CH-19 Sweet Extract", Int. J. Toxicol. 27 (Suppl. 3) (2008): 137-147. Capsinoids are hydrolyzed before absorption and break down to fatty acids and to vanillyl alcohol. According to human studies conducted to date, intact capsinoids are not present in the bloodstream following oral administration, suggesting minimal concern about untoward activation of TRPV1 receptors in other parts of the body. Single dose oral administration of up to 30 mg capsinoids did not raise blood pressure or heart rate in healthy volunteers, nor did administration of CH-19 Sweet.

Major capsinoids in nature

Capsiate (4-hydroxy-3-methoxybenzyl (E)-8-methyl-6-nonenoate) (CAS No. 205687-01-0) Dihydrocapsiate (4-hydroxy-3-methoxybenzyl 8-methylnonanoate) (CAS No. 205687-03-2) Nordihydrocapsiate (4-hydroxy-3-methoxybenzyl 7-methyloctanoate) (CAS No. 220012-53-3)

References

{{Reflist Biochemistry