Hot Chili Peppers Research Articles

Impact of Genetic Reduction of NMNAT2 on Chemotherapy-Induced Losses in Cell Viability In Vitro and Peripheral Neuropathy In Vivo.

Nicotinamide mononucleotide adenylyl transferases (NMNATs) are essential neuronal maintenance factors postulated to preserve neuronal function and protect against axonal degeneration in various neurodegenerative disease states. We used in vitro and in vivo approaches to assess the impact of NMNAT2 reduction on cellular and physiological functions induced by treatment with a vinca alkaloid (vincristine) and a taxane-based (paclitaxel) chemotherapeutic agent. NMNAT2 null (NMNAT2-/-) mutant mice die at birth and cannot be used to probe functions of NMNAT2 in adult animals. Nonetheless, primary cortical cultures derived from NMNAT2-/- embryos showed reduced cell viability in response to either vincristine or paclitaxel treatment whereas those derived from NMNAT2 heterozygous (NMNAT2+/-) mice were preferentially sensitive to vincristine-induced degeneration. Adult NMNAT2+/- mice, which survive to adulthood, exhibited a 50% reduction of NMNAT2 protein levels in dorsal root ganglia relative to wildtype (WT) mice with no change in levels of other NMNAT isoforms (NMNAT1 or NMNAT3), NMNAT enzyme activity (i.e. NAD/NADH levels) or microtubule associated protein-2 (MAP2) or neurofilament protein levels. We therefore compared the impact of NMNAT2 knockdown on the development and maintenance of chemotherapy-induced peripheral neuropathy induced by vincristine and paclitaxel treatment using NMNAT2+/- and WT mice. NMNAT2+/- did not differ from WT mice in either the development or maintenance of either mechanical or cold allodynia induced by either vincristine or paclitaxel treatment. Intradermal injection of capsaicin, the pungent ingredient in hot chili peppers, produced equivalent hypersensitivity in NMNAT2+/- and WT mice receiving vehicle in lieu of paclitaxel. Capsaicin-evoked hypersensitivity was enhanced by prior paclitaxel treatment but did not differ in either NMNAT2+/- or WT mice. Thus, capsaicin failed to unmask differences in nociceptive behaviors in either paclitaxel-treated or paclitaxel-untreated NMNAT2+/- and WT mice. Moreover, no differences in motor behavior were detected between genotypes in the rotarod test. Our studies do not preclude the possibility that complete knockout of NMNAT2 in a conditional knockout animal could unmask a role for NMNAT2 in protection against detrimental effects of chemotherapeutic treatment.

The Effectiveness of Different Palate Relievers Against a Hot Chili Pepper Sauce

Mexican food is a combination of strong flavors, and of course, spicy ingredients (hot chili peppers). However, not everybody has developed a liking or resistance to hot chili peppers, hence a method for relief from the burning feeling they provoke is necessary. The purpose of this study was to evaluate which palate reliever worked best to mitigate the aftertaste hotness induced by capsaicin, the component responsible for the hot sensation in chili peppers. The hypothesis was that a substance capable of dissolving capsaicin (a nonpolar substance) would be the best palate reliever, making olive oil a prime candidate. Sensory tests were done using 12 untrained panelists with high, medium, and low resistance to hotness, a homemade hot chili pepper sauce, and five palate relievers. Palate relievers with different solubility properties, milk and ice cream (emulsions), olive oil (nonpolar substance), and water and a soft drink (polar substances), were used to alleviate the hotness sensation after trying the hot sauce. Regardless of the panelists’ tolerance towards the hot sauce (low, medium, or high), all rated milk and ice cream to be the best palate relievers and the soft drink to be the worst. The best palate reliever was an emulsion (milk or ice cream) and not olive oil, as was initially hypothesized.

Effect of Heat Treatment on Phenolic and Flavonoid Compounds and Antioxidant Activities of Some Egyptian Sweet and Chilli Pepper

Raw and heat-treated (boiled) sweet and hot chilli pepper (Capsicum spp.) were evaluated for their contents of phenolic and flavonoid compounds and free radical-scavenging activity by DPPH• assay. Boiling was performed under the Egyptian household conditions. Total phenolic and total flavonoid contents were determined. Twenty six phenolic compounds and eleven flavonoid compounds were fractionated by HPLC. DPPH• assay demonstrated that both fresh and heat-treated pepper samples had a high antioxidant activity which correlated with their high contents of total phenolic and flavonoid compounds. Finally, the resulted data showed that total phenolic and total flavonoid contents were increased as the result of boiling treatment as well as the antioxidant activity.

Consumer preferences of Generation Y

Generation Y (born between 1982 and 2002) has caught the attention of researchers due to the sheer size of this consumer segment and also its significant spending power. The purpose of this exploratory research was to cluster Generation Y concertgoers to various concerts held in South Africa during 2012 and 2013 based on their age to identify and profile different market segments at the concerts. Data were collected at eight live music performances, during 2012 and 2013, by performers Linkin Park, Adam Lambert, Celtic Woman, Lady Gaga, Red Hot Chilli Peppers, Bon Jovi, Justin Bieber and Rodriguez. This resulted in a total factor analysis conducted to identify the main motives of Generation Yers to attend live music performances. Generation Yers were then divided into three groups based on their age in order to give a better idea of the differences among these concertgoers. Three Generation Y clusters were identified, namely, Tweens, Twixters and Tweeds. Analyses of variance, two-way frequency tables and χ2 tests showed significant differences between the segments in terms of socio-demographic and behavioural characteristics as well as motives. Based on the results, it is evident that generation theory needs to be taken into consideration, and it can be a useful tool to segment markets.

Capsaicin Enhances the Drug Sensitivity of Cholangiocarcinoma through the Inhibition of Chemotherapeutic-Induced Autophagy.

Cholangiocarcinoma (CCA), a devastating cancer with a poor prognosis, is resistant to the currently available chemotherapeutic agents. Capsaicin, the major pungent ingredient found in hot red chili peppers of the genus Capsicum, suppresses the growth of several malignant cell lines. Our aims were to investigate the role and mechanism of capsaicin with respect to the sensitivity of CCA cells to chemotherapeutic agents. The effect of capsaicin on CCA tumor sensitivity to 5-fluorouracil (5-FU) was assessed in vitro in CCA cells and in vivo in a xenograft model. The drug sensitivity of QBC939 to 5-FU was significantly enhanced by capsaicin compared with either agent alone. In addition, the combination of capsaicin with 5-FU was synergistic, with a combination index (CI) < 1, and the combined treatment also suppressed tumor growth in the CCA xenograft to a greater extent than 5-FU alone. Further investigation revealed that the autophagy induced by 5-FU was inhibited by capsaicin. Moreover, the decrease in AKT and S6 phosphorylation induced by 5-FU was effectively reversed by capsaicin, indicating that capsaicin inhibits 5-FU-induced autophagy by activating the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway in CCA cells. Taken together, these results demonstrate that capsaicin may be a useful adjunct therapy to improve chemosensitivity in CCA. This effect likely occurs via PI3K/AKT/mTOR pathway activation, suggesting a promising strategy for the development of combination drugs for CCA.

Capsaicin Interaction with TRPV1 Channels in a Lipid Bilayer: Molecular Dynamics Simulation

Transient receptor potential vanilloid subtype 1 (TRPV1) is a heat-sensitive ion channel also involved in pain sensation, and is the receptor for capsaicin, the active ingredient of hot chili peppers. The recent structures of TRPV1 revealed putative ligand density within the S1 to S4 voltage-sensor-like domain of the protein. However, questions remain regarding the dynamic role of the lipid bilayer in ligand binding to TRPV1. Molecular dynamics simulations were used to explore behavior of capsaicin in a 1-palmitoyl-2-oleoyl phosphatidylcholine bilayer and with the target S1–S4 transmembrane helices of TRPV1. Equilibrium simulations reveal a preferred interfacial localization for capsaicin. We also observed a capsaicin molecule flipping from the extracellular to the intracellular leaflet, and subsequently able to access the intracellular TRPV1 binding site. Calculation of the potential of mean force (i.e., free energy profile) of capsaicin along the bilayer normal confirms that it prefers an interfacial localization. The free energy profile indicates that there is a nontrivial but surmountable barrier to the flipping of capsaicin between opposing leaflets of the bilayer. Molecular dynamics of the S1–S4 transmembrane helices of the TRPV1 in a lipid bilayer confirm that Y511, known to be crucial to capsaicin binding, has a distribution along the bilayer normal similar to that of the aromatic group of capsaicin. Simulations were conducted of the TRPV1 S1–S4 transmembrane helices in the presence of capsaicin placed in the aqueous phase, in the lipid, or docked to the protein. No stable interaction between ligand and protein was seen for simulations initiated with capsaicin in the bilayer. However, interactions were seen between TRPV1 and capsaicin starting from the cytosolic aqueous phase, and capsaicin remained stable in the majority of simulations from the docked pose. We discuss the significance of capsaicin flipping from the extracellular to the intracellular leaflet and mechanisms of binding site access by capsaicin.

Capsaicin-induced genotoxic stress does not promote apoptosis in A549 human lung and DU145 prostate cancer cells

Capsaicin is the major pungent component of the hot chili peppers of the genus Capsicum, which are consumed worldwide as a food additive. More recently, the selective action of capsaicin against cancer cells has been reported. Capsaicin was found to induce apoptosis and inhibit proliferation of a wide range of cancer cells in vitro, whereas being inactive against normal cells. As data on capsaicin-induced genotoxicity are limited and the effects of capsaicin against human lung A549 and DU145 prostate cancer cells were not explored in detail, we were interested in determining whether capsaicin-associated genotoxicity may also provoke A549 and DU145 cell death. Capsaicin-induced decrease in metabolic activity and cell proliferation, and changes in the cell cycle were limited to high concentrations used (≥100μM), whereas, at lower concentrations, capsaicin stimulated both DNA double strand breaks and micronuclei production. Capsaicin was unable to provoke apoptotic cell death when used up to 250μM concentrations. Capsaicin induced oxidative stress, but was ineffective in provoking the dissipation of the mitochondrial inner transmembrane potential. A different magnitude of p53 binding protein 1 (53BP1) recruitment contributed to diverse capsaicin-induced genotoxic effects in DU145 and A549 cells. Capsaicin was also found to be a DNA hypermethylating agent in A549 cells. In summary, we have shown that genotoxic effects of capsaicin may contribute to limited susceptibility of DU145 and A549 cancer cells to apoptosis in vitro, which may question the usefulness of capsaicin-based anticancer therapy, at least in a case of lung and prostate cancer.

Preparation and Evaluation of PLGA Coated Capsaicin Magnetic Nanoparticles for Target Site-Specific Pain Therapeutics

Pain accompanies several diseases including arthritis, cancer, diabetes, and often manifests as a disease itself. Currently, narcotic and non-narcotic drugs that are used to treat pain have several unwanted side effects due to their addiction, use dependence, and systemic side effects. A potential solution is to develop a target site-specific magnetic nanoparticle based delivery of analgesics. Transient Receptor Potential Vanilloid 1 (TRPV1; capsaicin receptor) is a non-selective cation channel protein, which mediates nociceptive pain and inflammation and is a target to develop therapeutics against chronic pain. Capsaicin, an ingredient of hot chili peppers, desensitizes TRPV1 and inhibits noxious pain. Here, we present the development and characterization of capsaicin magnetic nanoparticles (CMN) for site-specific pain therapeutics. Poly-L-lactide coglycollide (PLGA) coated CMN (PCMN) was prepared by solvent evaporation/coprecipitation technique and determined the size of CMN by transmission electron microscopy. Further, we determined the drug loading, encapsulation efficiency and pharmacokinetic release profiles of capsaicin from PCMN in vitro and examined the ability of PCMN to activate TRPV1, by intracellular Ca2+ imaging. Thermogram of CMN and crystalline nature of capsaicin were determined by differential scanning calorimetry and x-ray diffraction techniques, respectively. Next, we analyzed the intracellular localization of nanoparticles using fluorescein as a model drug. Finally, we characterized the anti-nociceptive potential of PCMN by intraplantar injection of PCMN in mice model of inflammation and pain. Our data demonstrate that PLGA coated CMN can be developed as a novel site-specific analgesic. Currently, we are investigating the site-specific action of PCMN under the influence of an external magnetic field. This novel method of drug-delivery will revolutionize therapeutics, since it will prevent the undesired side effects.

Relationship of 6-n-Propylthiouracil Taste Intensity and Chili Pepper Use with Body Mass Index, Energy Intake, and Fat Intake within an Ethnically Diverse Population

BackgroundOne of the weight-loss strategies that has attracted attention is the use of spicy foods. It has been suggested that spicy food preference is related to a genetically predetermined sensitivity to the bitter compound 6-n-propylthiouracil (PROP). ObjectiveOur aim was to examine the relationship of PROP taste intensity and hot chili pepper use with body mass index (BMI), energy intake, and fat intake. DesignThis study utilized a cross-sectional design. Participants/settingThe sample included 350 subjects (154 male, 196 female) ages 18 to 55 years living in the New York City area. Main outcome measuresBMI was calculated by measuring weight and height, and the sensitivity to PROP was evaluated using the PROP filter paper method. Subjects also rated the frequency of usage and preference for hot chili pepper using a chili pepper questionnaire. Their daily energy and fat intake were assessed using a food frequency questionnaire. Statistical analyses performedAn independent sample t-test compared subject characteristics between groups based on sex, PROP status, and hot chili pepper user status for the continuous variables, and the χ2 test was used for categorical variables. One-way analysis variance examined the differences in subject characteristics across four ethnicities. To predict BMI, energy intake, and fat intake, multiple linear regression models were fit with the covariates of age, sex, ethnicity, chili pepper score, and PROP mean. ResultsThe values for BMI, energy intake, and fat intake of PROP tasters were significantly lower than those of PROP nontasters (P=0.03, P<0.001, and P<0.001, respectively). The energy intake of chili pepper nonusers was significantly lower than that of chili pepper users (P=0.02), while there was no significant difference in fat intake between chili pepper users and nonusers. ConclusionsThis study suggests that PROP taste sensitivity contributes more to the prediction of energy and fat intake than chili pepper use.

Pain as Social Glue: Shared Pain Increases Cooperation

Even though painful experiences are employed within social rituals across the world, little is known about the social effects of pain. We examined the possibility that painful experiences can promote cooperation within social groups. In Experiments 1 and 2, we induced pain by asking some participants to insert their hands in ice water and to perform leg squats. In Experiment 3, we induced pain by asking some participants to eat a hot chili pepper. Participants performed these tasks in small groups. We found evidence for a causal link: Sharing painful experiences with other people, compared with a no-pain control treatment, promoted trusting interpersonal relationships by increasing perceived bonding among strangers (Experiment 1) and increased cooperation in an economic game (Experiments 2 and 3). Our findings shed light on the social effects of pain, demonstrating that shared pain may be an important trigger for group formation.

Aromatized olive oils: Influence of flavouring in quality, composition, stability, antioxidants, and antiradical potential

In the present work different flavourings (garlic, hot chili peppers, laurel, oregano and pepper) commonly used in Mediterranean cuisine were added to olive oils from Cv. Cobrançosa. Flavouring influence in olive oils quality, fatty acids profile, tocopherols and tocotrienols composition, antiradical activity, total phenols content and oxidative stability were evaluated.Garlic addition induced an increase in free acidity values (from 0.6 to 0.8%), but the remaining quality indices weren't negatively affected. Fatty acids profile changed but values remained under the limits of extra-virgin olive oils. Olive oils were nutritionally enriched due to the increase in vitamin E, mainly in oils flavoured with hot chili pepper (198.6 mg/kg). Antioxidant properties were influenced as well. Total phenols content decreased in all flavoured olive oils (control with 345.7 mg CAE/kg; oregano 293.8 mg CAE/kg) but the capability to counteract oxidation was generally improved (control with 9.4 h and oregano with 10.4 h). The addition of flavouring influenced quality, composition and olive oils characteristics being possible to separate them according to the flavouring used by applying chemometrics.

Capsaicin: a potent inhibitor of carbonic anhydrase isoenzymes.

Carbonic anhydrase (CA, EC 4.2.1.1) is a zinc containing metalloenzyme that catalyzes the rapid and reversible conversion of carbon dioxide (CO2) and water (H2O) into a proton (H+) and bicarbonate (HCO3–) ion. On the other hand, capsaicin is the main component in hot chili peppers and is used extensively used in spices, food additives and drugs; it is responsible for their spicy flavor and pungent taste. There are sixteen known CA isoforms in humans. Human CA isoenzymes I, and II (hCA I and hCA II) are ubiquitous cytosolic isoforms. In this study, the inhibition properties of capsaicin against the slow cytosolic isoform hCA I, and the ubiquitous and dominant rapid cytosolic isozymes hCA II were studied. Both CA isozymes were inhibited by capsaicin in the micromolar range. This naturally bioactive compound has a Ki of 696.15 µM against hCA I, and of 208.37 µM against hCA II.

Neuroprotection induced by N-acetylcysteine and selenium against traumatic brain injury-induced apoptosis and calcium entry in hippocampus of rat.

Neurodegeneration associated with acute central nervous system injuries and diseases such as spinal cord injury and traumatic brain injury (TBI) are reported to be mediated by the regulation of apoptosis and oxidative stress through Ca(2+) influx. The thiol redox system antioxidants, such as N-acetylcysteine (NAC) and selenium (Se), display neuroprotective activities mediated at least in part by their antioxidant and anti-inflammatory properties. However, there are no reports on hippocampal apoptosis, cytosolic reactive oxygen species (ROS), or Ca(2+) values in rats with an induced TBI. Therefore, we tested the effects of Se and NAC administration on apoptosis, oxidative stress, and Ca(2+) influx through TRPV1 channel activations in the hippocampus of TBI-induced rats. The 32 rats were divided into four groups: control, TBI, TBI + NAC, and TBI + Se groups. Intraperitoneal administrations of NAC and Se were performed at 1, 24, 48, and 72 h after TBI induction. After 3 days, the hippocampal neurons were freshly isolated from the rats. In cytosolic-free Ca(2+) analyses, the neurons were stimulated with the TRPV1 channel agonist capsaicin, a pungent compound found in hot chili peppers. Cytosolic-free Ca(2+), apoptosis, cytosolic ROS levels, and caspase-3 and -9 activities were higher in the TBI group than control. The values in the hippocampus were decreased by Se and NAC administrations. In conclusion, we observed that NAC and Se have protective effects on oxidative stress, apoptosis, and Ca(2+) entry via TRPV1 channel activation in the hippocampus of this TBI model, but the effect of NAC appears to be much greater than that of Se. They are both interesting candidates for studying the amelioration of TBIs.

Microwave and Ultrasound-Assisted Extraction of Capsaicinoids From Chili Peppers (Capsicum annuum L.) in Flavored Olive Oil

&lt;p&gt;The extraction of flavoring compounds from different plants and aromatic herbs has been using since ancient times in vegetable oils to enhance their aroma and taste, whereas the technology of production has changed over time. Our work aimed to evaluate alternative technologies for the production of aromatized olive oil such as ultrasound- and microwave-assisted extraction in comparison to traditional infusion or maceration of dried red hot chili pepper (10% w/v for 7 days). For the ultrasonic treatment, samples of olive oil were prepared by adding 10% and 20% dried chili pepper and subjected to ultrasound-extraction for 10 or 20 minutes. For microwave extraction, samples were added with 20% chili powder and treated for 10, 30 or 60 seconds. Capsaicinoids were quantified by HPLC-DAD directly in the flavored olive oil and antioxidant activity was evaluated by ABTS&lt;sup&gt;+&lt;/sup&gt; method. Capsaicinoids analysis in aromatized olive oil treated 20 minutes by ultrasound resulted about 130 ppm (capsaicin and hydroxycapsaicin), when 10% chili powder was used, while it was 250 ppm when 20% chili was used. The content of capsaicinoids extracted by traditional infusion was always higher for both concentrations of chili powder studied. The concentration of capsaicinoids in samples treated by microwaves extraction seem to be dependent on the treatment time, resulting 130 and 230 ppm capsaicinoids for 10 and 60 seconds of treatment, respectively. In conclusion, the production of flavored olive oils by using technologies such as microwave and ultrasound-extraction could allow the production of high quality oils, with fast and cost-effectively methods.&lt;/p&gt;

Transient receptor potential vanilloid 1 (TRPV1) antagonism in patients with refractory chronic cough: A double-blind randomized controlled trial

Inhalation of capsaicin, the extract of hot chili peppers, induces coughing in both animals and human subjects through activation of transient receptor potential vanilloid 1 (TRPV1) on airway sensory nerves. Therefore the TRPV1 receptor is an attractive target for the development of antitussive agents. We sought to assess the antitussive effect of TRPV1 antagonism in patients with refractory chronic cough. Twenty-one subjects with refractory chronic cough (>8 weeks) attending a specialist clinic were recruited to a randomized, double-blind, placebo-controlled crossover trial assessing a TRPV1 antagonist (SB-705498). Cough reflex sensitivity to capsaicin (concentration of capsaicin inducing at least 5 coughs) and 24-hour cough frequency were coprimary end points assessed after a single dose of SB-705498 (600 mg) and matched placebo. Cough severity and urge to cough were reported on visual analog scales, and cough-specific quality of life data were also collected. Treatment with SB-705498 produced a significant improvement in cough reflex sensitivity to capsaicin at 2 hours and a borderline significant improvement at 24 hours compared with placebo (adjusted mean difference of+1.3 doubling doses at 2 hours [95% CI,+0.3 to+2.2; P= .0049] and+0.7 doubling doses at 24 hours [95% CI,+0.0 to+1.5; P= .0259]). However, 24-hour objective cough frequency was not improved compared with placebo. Patient-reported cough severity, urge to cough, and cough-specific quality of life similarly suggested no effect of SB-705498. This study raises important questions about both the role of TRVP1-mediated mechanisms in patients with refractory chronic cough and also the predictive value of capsaicin challenge testing in the assessment of novel antitussive agents.

The Penumbral Theory of Masochistic Pleasure

Being whipped, getting a deep-tissue massage, eating hot chili peppers, running marathons, and getting tattooed are all painful. Sometimes they are also pleasant—or so many people claim. Masochistic pleasure consists in finding such experiences pleasant in addition to, and because of, the pain. Masochistic pleasure presents a philosophical puzzle. Pains hurt, they feel bad, and are aversive. Pleasures do the opposite. Thus many assume that the idea of a pleasant pain is downright unintelligible. I disagree. I claim that cases of pleasant pains are more common than many philosophers suppose, and that they have no essential connection to either sex or psychopathology. I review several attempts to account for masochism that preserve the intuition that nothing can be both pleasant and painful at once. These account for some, but not all, cases of masochism. The stubborn remainder, I argue, are sensations that are genuinely pleasant and painful at once. I give an account of how that might be, focusing on boundary-pushing aspects of masochistic pleasure that have been largely overlooked in the literature. I show how, properly understood, pain and pleasure can coexist—and also why it is very rare for them to actually do so.

TRPV1 Channels Are Functionally Coupled with BK(mSlo1) Channels in Rat Dorsal Root Ganglion (DRG) Neurons

The transient receptor potential vanilloid receptor 1 (TRPV1) channel is a nonselective cation channel activated by a variety of exogenous and endogenous physical and chemical stimuli, such as temperature (≥42 °C), capsaicin, a pungent compound in hot chili peppers, and allyl isothiocyanate. Large-conductance calcium- and voltage-activated potassium (BK) channels regulate the electric activities and neurotransmitter releases in excitable cells, responding to changes in membrane potentials and elevation of cytosolic calcium ions (Ca2+). However, it is unknown whether the TRPV1 channels are coupled with the BK channels. Using patch-clamp recording combined with an infrared laser device, we found that BK channels could be activated at 0 mV by a Ca2+ influx through TRPV1 channels not the intracellular calcium stores in submilliseconds. The local calcium concentration around BK is estimated over 10 μM. The crosstalk could be affected by 10 mM BAPTA, whereas 5 mM EGTA was ineffectual. Fluorescence and co-immunoprecipitation experiments also showed that BK and TRPV1 were able to form a TRPV1-BK complex. Furthermore, we demonstrated that the TRPV1-BK coupling also occurs in dosal root ganglion (DRG) cells, which plays a critical physiological role in regulating the “pain” signal transduction pathway in the peripheral nervous system.

Neuroprotection induced by N-acetylcysteine against cytosolic glutathione depletion-induced Ca2+ influx in dorsal root ganglion neurons of mice: Role of TRPV1 channels

Glutathione (GSH) and N-acetylcysteine (NAC) are thiol-containing antioxidants, and also act through a direct reaction with free radicals. Transient receptor potential vanilloid 1 (TRPV1) is the principal transduction channel serving as a polymodal detector. Despite the importance of oxidative stress in pain sensitivity, its role in TRPV1 modulation is poorly understood. NAC may also have a regulator role on TRPV1 channel activity in the dorsal root ganglion (DRG) neuron. Therefore, we tested the effects of GSH and NAC on TRPV1 channel current, Ca2+ influx, oxidative stress and caspase activity in the DRG of mice.DRG neurons were freshly isolated from mice and the neurons were incubated for 6 and 24h with buthionine sulfoximine (BSO). Pretreatment of cultured DRG neurons with NAC, results in a protection against oxidative damages. This neuroprotection is associated with the attenuation of a Ca2+ influx triggered by oxidative agents such as H2O2, 5,5′-dithiobis-(2-nitrobenzoic acid) and GSH depletion via BSO. Here, we demonstrate the contribution of cytosolic factors (related to thiol group depletion) on the activation of TRPV1 channels in this mechanism. TRPV1 channels are activated by various agents including capsaicin (CAP), the pungent component of hot chili peppers, and are blocked by capsazepine. An oxidative environment also increased CAP-evoked TRPV1 currents in the neurons. When NAC and GSH were included in the patch pipette as well as extracellularly in the chamber, TRPV1 channels were not activated by CAP and H2O2. TRPV1 inhibitors, 2-aminoethyl diphenylborinate and N-(p-amylcinnamoyl)anthranilic acid strongly reduced BSO-induced oxidative toxicity and Ca2+ influx, in a manner similar to pretreatment with NAC and GSH. Caspase-3 and -9 activities of all groups were not changed by the agonists or antagonists.In conclusion, in our experimental model, TRPV1 channels are involved in the oxidative stress-induced neuronal death, and negative modulation of this channel activity by GSH and NAC pretreatment may account for their neuroprotective activity against oxidative stress.

Influence of varying estrogen levels on trigeminal CGRP release in healthy women

Migraine is 2-3 times more prevalent in women than in men, with frequent perimenstrual attacks. TRPV1 receptors on sensory nerve endings of the trigeminal track are important in mediating migraine attacks by releasing the vasodilator calcitonin gene-related peptide (CGRP). Variation in estrogen levels during the menstrual cycle may have an influence on the sensitivity of the TRPV1 receptor or on the amount of CGRP in perivascular nerve terminals and hence on CGRP release. Capsaicin, the active ingredient of hot chili peppers, stimulates the TRPV1 receptor and causes CGRP-dependent vasodilatation [1]. We set up a model to study trigeminal CGRP release in humans. We compared the vasodilator effects of capsaicin application and electrical stimulation on the forehead skin. Healthy women, not using hormonal contraceptives (age: 18-45, n=14), were studied with a Laser Doppler Imager on day 19-21 of their menstrual cycle and on day 1-2 of their menstruation. A 0.2 mM and a 20 mM capsaicin solution were applied to the skin. In addition, iontophoresis of saline was performed as a TRPV1-independent stimulus. Increases in dermal blood-flow (DBF) were measured. Blood samples were collected to measure estrogen levels. We measured higher DBF responses to application of 0.2 mM capsaicin (Max:226±34 a.u.) and 20 mM capsaicin (Max:507±39 a.u.) during day 1-2 (low estrogen levels: 15±2 pg/ml) of the menstruation, than during day 19-21 (high estrogen levels: 67±9 pg/ml) of the menstrual cycle (Max:176±34 a.u. and 432±33 a.u. for 0.2 mM and 20 mM, respectively, P<0.05). There was no difference in DBF responses to electrical stimulation of the forehead skin, suggesting that the observed changes are related to the sensitivity of the TRPV1 receptor. Our results indicate an influence of variation in estrogen levels on trigeminal CGRP release, with the highest reactivity observed around the menstruation when estrogen levels are low. This mechanism may, at least partly, explain the high incidence of migraine attacks during the perimenstrual period.

Optimization of ultrasonic-assisted extraction procedure of capsaicinoids from Chili peppers using orthogonal array experimental design

In this present study, the optimal conditions of ultrasonic-assisted extraction (UAE) of capsaicinoids from hot Chili peppers were determined for large scale preparation. First, single factor experiments were performed to optimize the extraction procedure of capsaicinoids, and initial optimized results were: ratio of solvent to mass of 6 to 10 ml/g, extraction temperature of 25 to 35°C, and extraction time of 0 to 30 min. Then, an orthogonal array experimental design (L 9 (3 4 )) was used to further optimize the extraction procedure. The results of F-test and P-value indicated that the effect order on extraction yield of capsaicinoids from high to low was ratio of solvent to mass, extraction time, and extraction temperature. The maximum extraction yield of capsaicinoids was obtained at ratio of solvent to mass of 10 ml/g, extraction time of 40 min, and extraction temperature of 25°C. Under these conditions, the extraction yields of capsaicinoids were 2.35 ± 0.042 and 3.92 ± 0.089 mg/g for conventional and UAE methods, respectively. Keywords: Chili pepper, ultrasonic-assisted extraction, capsaicinoids, orthogonal array design, single factor experiments