Capsaicinoids naturally occurring

The substrates for capsaicinoid synthase were first defined by Fujiwake et al. [70] to be vanillylamine and 8-methyl-6-nonenoyl CoA. The synthesis of dihydrocapsaicin and the other naturally occurring variants are achieved by condensation of vanillylamine with the respective branched chain acyl, for example, 8-methylnonanoyl-CoA. The gene for capsaicinoid synthase has been linked to an acyltransferase At3 or Punl) cloned by Kim et al. [66] and mapped to the C locus on chromosome 2 [71, 72], Direct biochemical confirmation of capsaicinoid synthase remains to be established. 

Krajewska A, Powers J (1988) Sensory properties of naturally occurring capsaicinoids. J Food Sci 53 902-905... 

The formation of acyl conjugates of vanillamine (capsaicinoids, 20) or vanillic alcohol (capsinoids, 21) with various Cg/Ci3 alkenoic and alkanoic acids is a unique chemical trait of plants from the genus Capsicum. Hot peppers are characterized by the presence of vanillyl conjugates of the amide type, absent or replaced by their nonpungent ester isosters (capsinoids) in bell (sweet) peppers [19]. Indeed, the difference between the sensory properties of capsaicin (la) and its naturally occurring ester analog capsiate (22) is a remarkable example of the biological relevance of isosterism. 

As for the capsaicin derivatives, it was shown that only the trans isomer is naturally occurring. Biologically, it was reported that purified capsaicin depletes substance P stores in sensory neurons and blocks further synthesis of this neuropeptide. Therapeutically, capsaicin has been used successfully to treat several painful conditions (e.g., rheumatoid arthritis, osteoarthritis, and various peripheral neuropathic disorders).To date, there are no capsaicinoids that have proven to be as potent as the parent compound capsaicin for neuropeptide activity [6]. 

The capsaicinoids are extracted using different solvents and more recently ultrasound-assisted extraction [61], extraction by means of supercritical fluids [65], extraction by pressurized liquids [58] and enzymatic extraction [59], and analyzed by HPLC [64,93-95], GC [72-76], hyphenated systems as HPLC-MS [96-100], and GC-MS [77]. Normally the GC methods require derivatization of the compounds to make them sufficiently volatile for determination. There are many other reported papers have been found in the literature for the analytical separation, quantitation, and identification of naturally occurring capsaicinoids in different matrices. Select matrices are discussed here. 

Krajewska, A. M. and Power, J. J. 1986. Isolation of naturally occurring capsaicinoids by reversed phase low pressure liquid chromatography. J. Chromatogra. A 367 267-270. 

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