Determination of capsaicin and zucapsaicin in human serum by high-performance liquid chromatography with fluorescence detection

Quantitative determination of major capsaicinoids in serum by ELISA and time-resolved fluorescent immunoassay based on monoclonal antibodies

To monitor capsaicinoids in serum on-site, three new monoclonal antibodies (mAbs) were firstly proposed using a conjugate of 4-[(4-hydroxy-3-methoxybenzyl) amino]-4-oxobutanoic acid as the immunogen. Among them, the YQQD8 mAb showed the highest sensitivity and cross-reactivity to major capsaicinoids, such as capsaicin, dihydrocapsaicin and N-vanillylnonanamide. A competitive indirect enzyme-linked immunosorbent assay (icELISA) and a time-resolved fluorescent immunochromatographic assay (TRFICA) were established based on this mAb. The linear range was 1.1-27.0ngmL(-1) for icELISA and 1.9-62.5ngmL(-1) for TRFICA and the limit of detection (LOD) of TRFICA was 1.5ngmL(-1). To decrease the interference of sample components and increase accuracy, serum samples were diluted four times before assays. As a result, the linear range of serum samples was 4.6-107.9ngmL(-1) for icELISA and 7.6-250.0ngmL(-1) for TRFICA. Both icELISA and TRFICA showed good recoveries (91.0-112.8% for icELISA and 87.6-111.5% for TRFICA) and concordant results in spiked experiments. Overall, this is the first report of immunoassay based on the mAbs for quantitative determination of major capsaicinoids, and the results demonstrate that both methods can meet the demands of rapid on-site assay for capsaicinoids in serum samples.

Fast method for capsaicinoids analysis from Capsicum chinense fruits

Chili peppers are widely utilized in the world as savory food additives due the pungency induced by the capsaicinoids. Also, these compounds have functional properties as antimutagenic, antitumoral, antioxidant and analgesic. These characteristics increase the interest in this compound class, hence the capsaicinoid analysis must be reproducible and accurate. This study aimed to develop and validate a fast, efficient and reproducible method to analyze capsaicinoids in Brazilian Capsicum chinense fruits. The extracts were obtained after an optimization step that indicated the condition 100% of methanol and 10min on ultrasound assisted extraction. The analyses were carried out in an ultra high performance liquid chromatographic system with detection by a photo diode array and mass spectrometer. The analytical method developed permits the separation of 8 capsaicinoids in 4min of time analysis expending only 2mL of solvent as mobile phase. The validation parameters evaluated for the method show the effectiveness and satisfactory performance to answer the analytical needs of this research area, presenting low values to relative standard deviation in repeatability and reproducibility and recoveries ranged from 88 to 112% for capsaicin and 89 to 109% for dihydrocapsaicin. In the extracts from different accessions of C. chinense fruits analyzed, the contents of capsaicin and dihydrocapsaicin were in the range of 156-1442μgg^-1 and 26-478μgg^-1 of fresh fruit, respectively, showing the large application of this method for quantification of the two major capsaicinoids in fast routine analysis and may be used to determine the concentrations of other minor capsaicinoids once appropriate standards are available.

Stability indicating reverse phase high performance liquid chromatography method for the estimation of capsaicin

Background:

Stability Indicating Method (SIM) is a quantitative analytical procedure used to detect a decrease in the amount of the active pharmaceutical ingredient (API) present due to degradation. According to Food and Drug Administration (FDA) guidelines, an SIM is defined as a validated analytical procedure that accurately and precisely measures active ingredients (drug substance or drug product) free from potential interferences, such as degradation products, process impurities, excipients, or other potential impurities, and the FDA recommends that all assay procedures for stability studies be stability indicating. Here in this study we developed simple precise and accurate stability indicating reverse-phase high-performance liquid chromatographic (RP-HPLC) assay to analyze capsaicin (CAP) at concentrations from 70 to 130 μg/mL.

Materials and Methods:

HPLC equipped with Photo diode Array (PDA) detector, Pump model 600E of Waters and Empower software. Column used for the separation is ODS (250 × 4.6 mm) with particle size 5 μm and all the reagents and water were of HPLC grade.

Results:

The chromatographic separation was carried out using mobile phase Acetonitrile (ACN):water:buffer::75:10:15 with a flow rate of 1 mL/min on a C18 column. The concentration of the eluting compounds was monitored by a UV detector at 280 nm. No interferences were observed when stress conditions were applied and analyzed. Linearity was established using visual method, residuals plot, Dixon, and lack of fitness test. Limit of detection and limit of quantification was found to be 52.9 and 160 ng/mL, respectively. Recovery studies prove this method as useful in recovering the analytes. Relative Standard Deviation (RSD) of inter- and intraday precision within the acceptable limit of 2% proves that this method is precise. No degradation was found with alkaline conditions, thermal and photodegradation.

Conclusions:

This study can be used for successful separation of CAP and its potential degradants in bulk and formulations. UV spectra of one of the degradants are also presented here and can be the basis to generate chemistry of potential degradants when CAP is kept under environmental conditions.

Chemical and pharmacological aspects of capsaicin

Capsaicin is a unique alkaloid found primarily in the fruit of the Capsicum genus and is what provides its spicy flavor. Generally extracted directly from fruit, high demand has driven the use of established methods to increase production through extraction and characterization. Over time these methods have improved, usually be applying existing techniques in conjunction. An increasingly wide range of potential applications has increased interest in capsaicin. Especially compelling are the promising results of medical studies showing possible beneficial effects in many diseases. Capsaicin’s pungency has limited its use in clinical trials to support its biological activity. Characterization and extraction/ synthesis of non-pungent analogues is in progress. A review is made of capsaicin research focusing mainly on its production, synthesis, characterization and pharmacology, including some of its main potential clinical uses in humans.

Reversed-phase liquid chromatography and argentation chromatography of the minor capsaicinoids

An investigation of the liquid chromatography of the minor capsaicinoids in a commercial capsaicinoid mixture is reported. Twelve stationary phases including C8, C18, C30, phenyl, and cation-exchange chemistries were examined in combination with isocratic aqueous methanol and aqueous acetonitrile mobile phases. A phenyl stationary phase and aqueous acetonitrile mobile phase baseline-resolved 7 of 11 capsaicinoids, and selected ion chromatograms (LC-ESI-MS) demonstrated this was the most effective reversed-phase separation. Argentation chromatography with an alkyl or phenyl column and aqueous silver nitrate-methanol mobile phase revealed the presence of the 6-ene-8-methyl and 6-ene-9-methyl homocapsaicin isomers and the absence of 7-ene-9-methyl homocapsaicin. A mixed phenyl-cation-exchange stationary phase (charged with silver ion) enabled unique and useful separations of the capsaicinoids.

Chemical analysis of freshly prepared and stored capsaicin solutions: implications for tussigenic challenges

The purpose of this study was to assess the stability of stored capsaicin solutions and the actual concentrations of prepared solutions. Capsaicin solutions ranging in concentration from 0.5 to 128 microM were mixed and analyzed using high performance liquid chromatography. Samples of varying concentrations were then stored under 4 environmental conditions: 4 degrees C and protected from light, room temperature (RT) exposed to light, RT protected from light, and -20 degrees C and protected from light. The concentrations were measured every other month for 1 year. Actual concentrations of freshly prepared solutions were on average 88.3% of predicted. For solutions stored at 4 degrees C, there was a decrease only in the lower concentrations (0.5, 1, and 2 microM) after 2 months (P=0.003). Solutions stored at RT exposed to light decreased in concentration after 6 months (P=0.020), and solutions stored at RT protected from light decreased in concentration after 4 months (P=0.026). The group stored at -20 degrees C decreased in concentration after 1 year (P=0.033). We conclude that the actual concentration of capsaicin solution is less than predicted, and solutions of 4 microM or higher concentration are stable for 1 year if stored at 4 degrees C protected from light.

Optimization of high-performance liquid chromatographic parameters for the determination of capsaicinoid compounds using the simplex method

A high-performance liquid chromatographic method was developed for the analysis of capsaicinoid compounds, the pungent principles of capsicum fruits. A sequential simplex method was applied to optimize the chromatographic response function used to assess the quality of separation by varying the chromatographic parameters. The separation was achieved in 11 min using a C-8 column of 15-cm length and 4.6 mm diameter using a UV detector. A flow rate of 1.15 ml min(-1) at a column temperature of 43.5 degrees C using 63.7% methanol in water gave the most efficient separation. The method was found to be suitable for the determination of the major capsaicinoid compounds in the capsicum samples.

A fatal case of pepper poisoning

An 8 month old infant died as the result of administration of a traditional remedy, given orally as an infusion of a red powder. The symptoms on admission were coughing with diarrhoea and vomiting. Analysis of the powder using high-performance liquid chromatography (HPLC) confirmed the suspicion of capsaicin. Pepper preparations, which are used as traditional medicines, are highly toxic and their use on infants should be discouraged.