Capsaicinoids natural

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... 

All these aspects have been recently studied in two publications (10.13). which standardized the dilution test for pungency and clearly established correlations with the estimates of total, and even individual, capsaicinoids. These papers also review the earlier attempts at standardisation. Two approaches are possible use of a fairly homogenous panel to determine the threshold pungency response due to the stimuli or use of a general panel to determine the average threshold of the panel for the stimuli. The second value will have wider applicability in use situations but the first value should be useful for correlative work. The two methods approach one another when panels are screened and trained to avoid all bias factors, and when carefully planned dilution levels, details of panel procedure, treatment of data, and expression of results are adopted. In fact, the results published in the two independent studies (10.13). show close values, 17+0.9 million for natural capsaicinoids and 16.1+0.6 million for pure capsaicin and dihydrocapsaicin. 

Table II. Pungency stimulants of capsicum -the natural capsaicinoids...

Figure 1. Tracings of separation of total capsaicinoids of capsicum extracts and reference pure compounds by paper chromatography Spot (1) red capsicum Spot (2) natural capsaicinoids pure Spot (3) green capsicum fresh and Spot (4) synthetic capsaicin (C) color (F) fat, and (Cv), capsaicinoids/capsaicin ((27) and...

Analysis of chemical constituents in fruits of red pepper (cv. Bugang) revealed five natural capsaicinoids. They were capsaicin, nordihydrocapsaicin, dihydrocapsaicin, vanillyl decanamide and homodihydrocap-saicin. The concentration of total capsaicinoids in fruits was 5.4mg/100g FW. Eleven carotenoids were identified, with a total concentration of 65 mg/100g FW. The con-... 

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. 

The combination of these elements generates the diversity of capsaicinoids reported to date. Generally, the major constituent of the capsaicinoid soup are capsaicin (la) and its dihydroderivative (lb). Commercial capsaicin potvder is an approximately 5 1 mixture of capsaicin and dihydrocapsaicin, while analytical (>95 %) capsaicin contains mainly nonivamide as impurity. Despite its trivial name of synthetic capsaicin, nonivamide is a natural trace constituent of capsicum oleoresin, and concentration >3 % are indicative of adulteration [26]. The addition of nonivamide to capsicum oleoresin has been detected in products from both the food and the pharmaceutical markets. Some of them have been found to contain exclusively nonivamide, even though capsaicin is the only individual constituent of capsicum oleoresin to be approved by the FDA for human use [26]. 

Linear capsiacinoids with a C9/C12 chain are only trace constituents of capsicum oleoresin, which mainly contains branched capsaicinoids. The acyl moiety of these compounds is produced by the branched chain fatty acids pathway (Scheme 4.1) [30[. Depending on the nature of the amino acid that acts as the acyl starter precursor, different capsaicinoids are formed. Thus, capsaicinoids of the iso series such as CPS and homocapsaicin I are derived from valine and leucine via isobutyrylCoA and isovalerylCoA, respectively, while those from the anteiso series such as homocapsaicin II originate from isoleucine via 2-methylbutyrylCoA (Scheme 4.1) [31[. The polymethylene moiety of norcapsaicin has one less carbon than capsaicin. The... 

Even in its simplified form, the Nelson protocol will deter the most enthusiast natural-product chemist. Unsurprisingly, alternative protocols have been described in the proprietary literature, and their sheer number testify to the ingenuity and commitment of chemists to solve what is still today a daunting task. Some modern modifications to the Nelson method from the proprietary literature include the use of supercritical carbon dioxide to reduce the extraction of pigments in the preparation of the oleoresin [54], and the recourse to macroporous adsorption resins [55] or to repeated extraction with aqueous silver nitrate to trap capsaicinoids and reduce the number of partition steps [56]. 

Other capsaicinoids are available. Pelargonic acid vanillylamide (PAVA or nonivamide), shown in Figure 12.10, is a synthetic form of capsaicin. Nonivamide was first synthesized by Nelson (1919). Nonivamide was originally found to be a minor component in Capsicum annum peppers (Constant and Cordell, 1996) however, the majority of PAVA is derived from synthesis rather than extraction from natural plant sources. As a result, the composition and concentration of PAVA can remain consistent (Haber et al, 2007). 

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]. 

Stage that requires high efficiency as well as speed, due to the complexity of the sample matrix, and hence it is particularly challenging to achieve the goals. Therefore, the development of a rapid, sensitive, and reproducible method has been required for separation and determination of capsaicinoid compounds. The addition of ultraperformance liquid chromatography-mass spectrometry (UPLC-MS) method fulfilled these aforementioned demands and showed some complementary advantages to the conventional HPLC-MS, u-HPLC methods in terms of shorter analysis times, low sample volume, and much improved sensitivity [71]. Therefore, nowadays this UPLC-MS technique is routinely performed in pharmaceutical industries and related contract research institutes, laboratories concerned with biochemistry, biotechnology, environmental analysis, natural product research, and several other research fields. The UPLC-MS method has successfully been applied for the determination of n-DHC, C, DHC, h-C, and h-DHC present in the varieties of hot peppers [71]. 

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. 

Sticher, O., Soldati, F., and Joshi, R. K., 1978, High-performance liquid chromatographic separation and quantitative determination of capsaicin, dihydrocapsaicin, nordihydro-capsaicin, and homodihydrocapsaicin in natural capsaicinoid mixtures and fructus capsid, J. Chromatogr. 166 221-231. 

Glycosides. Capsaicin P-o-glucopyranoside and dihydrocapsaicin P-o-glucopyra-noside have been discovered recently in the fruits of various pungent cultivars of C. annuum, C. chinense, and C. frutescens (Higashiguchi et al. 2006). They represent the first capsaicinoid glucosides in nature. However, they constitute only a very small quantity of the total capsaicinoid content in the fruits. 

Terashima S, Shimizu M, Horie S, Morita N (1991) Studies on aldose reductase inhibitors from natural products. IV. Constituents and aldose reductase inhibitory effect of Chrysanthemum morifolium, Bixa orellana and Ipomoea batatas. Chem Pharm Bull 39 3346-3347 Tewksbury JJ, Manchego C, Haak DC, Levey DJ (2006) Where did the chUi get its spice Biogeography of capsaicinoid production in ancestral wild chili species. J Chem Ecol 32 547-564... 

Examination of the capsaicinoid stmctures reveals a common feature, namely an aromatic ring possessing a methoxy and hydroxyl substituents. Because of the similarity of these structures to the natural substance vanilhn (Fig. 13), these pungent substances are collectively known as vanilloids [74]. 

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