Capsaicins and piperines

Chemesthesis. The term chemesthesis has been introduced to classify thermal and painful sensations experienced in the mouth (26). Chemesthesis refers to a chemical sensibility (mouthfeel) in which certain chemicals direcdy activate nerve fibers at the level of the basal membrane in the mouth. The sensations are analogous to similar effects at the skin surface where there is a close anatomical and functional relationship. Sensations include the "hot" of capsaicin and piperine, which are active components of chili and pepper, the coolness of menthol and the irritation of chemicals such as salt at high concentrations [FIGURE 4]. Some of the descriptive terms used to make qualitative distinctions in food sensations include pungency, freshness, tingling, burning and sharpness. 

Apart from the above mentioned cardiovascular and respiratory effects of AEA in vivo, the effect of intraperitoneal AEA, capsaicin, and piperine on gastrointestinal transit was investigated in mice. 

Suresh D, Srinivasan K (2006) Influence of curcumin, capsaicin, and piperine on the rat liver drug-metabolizing enzyme system in vivo and in vitro. Can J Physiol Pharmacol 84 1259-1265... 

Suresh D, Srinivasan K (2007) Studies on the in vitro absorption of spice principles -curcumin, capsaicin and piperine in rat intestines. Food Chem Toxicol 45 1437-1442... 

A number of phenylpropanoids are perceived as pungent by humans and presumably by other organisms. Among these are capsaicin (20), the pungent principle of peppers Capsicum species, Solanaceae) and piperine (21), the pungent principle of black pepper Piper nigrum, Piperaceae) (Fig. 8.9) (Harbome, 1982). 

The active compounds capsaicin and dihydrocapsaicin elute with a short retention time difference. A good separation free from peak tailing is necessary for the reliable peak integration for low RSD values at low concentration levels. It was found with different types of GC columns that the quality of the column deactivation, age of the column and matrix deposits have a detrimental effect on the capsaicin and dihydrocapsaicin peak shape and quantitative reproducibility. Also, piperine and cinnamaldehyde were affected while thymol always showed symmetrical peak shapes, apparently being unaffected by the increasingly active column film conditions. 

Synthetics. The lack of spice products to satisfy demand and the wide variation in price and availabihty have caused the manufacture of selected synthetics, chemically identical to the component in the natural spice, to replace the vital components of some spices. However, synthetic organic chemistry is not yet able to manufacture economically the many homologous piperine [94-62-2] components in black pepper or those capsaicin [404-86-4] amides in... 

The interactions between the endocrine and neural systems of the GIT are complex, include shared signaling molecules, and can be hard to separate. Therefore, it is likely that the influence(s) of some phytochemicals will cross over between neural and non-neural pathways. Corresponding with this, lumenal administration of capsaicin interacts with visceral neurons to increase GIT motility (Zittel et al., 2001 Topcu et al, 2002) and abrogates the decreased electrolyte and fluid secretion caused by piperine (Capasso et al., 2002). 

ZO026 Liu, L., and S. A. Simon. Similarities and differences in the currents activated by capsaicin, piperine and zingerone in rat trigeminal ganglion cells. J Neurophysiol 1996 76(3) 1858-1869. 

Several SM have been used by mankind for thousands of years22,27 as dyes (e.g., indigo, shikonine), flavors (e.g., vanillin, capsaicin, mustard oils), fragrances (e.g., rose oil, lavender oil and other essential oils), stimulants (e.g., caffeine, nicotine, ephedrine), hallucinogens (e.g., morphine, cocaine, mescaline, hyoscyamine, scopolamine, tetrahydrocannabinol), insecticides (e.g., nicotine, piperine, pyrethrin), vertebrate and human poisons (e.g., coniine, strychnine, aconitine) and even therapeutic agents (e.g., atropine, quinine, cardenolides, codeine, etc.). 

Returning to the question in the title of this section, capsaicin does not fall into any of the three classic types of nitrogen-bearing plant natural products, being neither a true alkaloid, a protoalkaloid, or a pseudoalkaloid. Capsaicin is oflimited distribution in Nature and shows pharmacological activity, but is non-basic, structurally unsophisticated, and not directly derived from an amino acidic precursor. On the other hand, the lack of attributes such as basicity, complexity, and an amino acidic pedigree can also be found in compounds commonly perceived as alkaloids. Thus, colchicine is neutral, ephedrine is structurally unsophisticated, and the nitrogen atom of the potato alkaloid solanine is not derived from an amino acid, but rather incorporated into as non-amino acidic framework by a transamination reaction. For the sake of clarity and consistency, it seems therefore convenient to adopt the modern definition of alkaloids, and consider capsaicin, as well as alkylamides such as piperine (18) and pellitorine (19), as such. 

Hot and spicy foods contain molecules that stimulate pain-detecting nerve endings. Two such molecules are piperine and capsaicin ... 

Piperine is the a ctive compound in white and black pepper and capsaicin is the active compound in chili peppers. The ring structures in piperine and capsaicin are shorthand notation. Each point where lines meet represents a carbon atom. ... 

Note The ring structures are all shorthand notation for rings of carbon atoms. In piperine, the first ring contains six carbon atoms and the second ring contains five carbon atoms (plus nitrogen). Also notice that CH3, CH2, and CH are shorthand for carbon atoms singly bonded to hydrogen atoms, b. piperine 0 sp, 11 sp2, and 6 sp3 carbons capsaicin 0 sp, 9 sp2, and 9 sp3 carbons ... 

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