Pungent Compounds Research Articles

Capsaicin inhibits proliferation and induces apoptosis in osteosarcoma cell lines via the mitogen‑activated protein kinase pathway.

Capsaicin, a pungent molecular compound present in many hot peppers, exerts anticancer activities against various human cancer cell lines by inducing apoptosis. However, the effects of capsaicin on human osteosarcoma (OS) as well as the related mechanisms remain to be fully elucidated. In the present study, the anticancer effects of capsaicin on 3 human OS cell lines (MG63, 143B and HOS) were investigated. Various concentrations of capsaicin (50–300 µM) effectively decreased cell viability in all 3 OS cell lines in a dose-dependent manner. Notably, capsaicin-induced apoptosis was observed when OS cells were treated with relatively high concentrations of capsaicin (starting at 250 µM). In addition, the mitochondrial apoptotic pathway was involved in the capsaicin-induced apoptosis in the OS cells. Meanwhile, our results also indicated that at relatively low concentrations (e.g., 100 µM), capsaicin could inhibit the proliferation, decrease the colony forming ability and induce G0/G1 phase cell cycle arrest of OS cells in a dose-dependent manner. Moreover, our results revealed that the anticancer effects induced by capsaicin on OS cell lines involved multiple MAPK signaling pathways as indicated by inactivation of the ERK1/2 and p38 pathways and activation of the JNK pathway. Furthermore, the results of animal experiments showed that capsaicin inhibited tumor growth in a xenograft model of human OS. In conclusion, these results indicate that capsaicin may exert therapeutic benefits as an adjunct to current cancer therapies but not as an independent anticancer agent.

Pungency Evaluation of Hydroxyl-Sanshool Compounds After Dissolution in Taste Carriers Per Time-Related Characteristics.

This study was conducted to investigate the sensory characteristics and temporal migration of hydroxyl-sanshool compounds at slight and moderate concentrations after dissolution in ethanol-water, saccharose, NaCl, and MSG via 2-AFC, time intensity (TI) and temporal dominance of sensations (TDS) methods. The pungency detection threshold (DT) was suppressed in saccharose while NaCl and MSG solutions showed no effect on pungency DT. The area under the curve (AUC) of pungency increased in NaCl and MSG solutions and decreased significantly in saccharose solution. Imax (maximal intensity) also increased in NaCl and MSG at low concentrations of hydroxyl-sanshool compounds. The temporally dominant sensations and migration of said sensations across the oral cavity differed among different carriers. Low levels of pungency compounds were characterized by tingling first in the tongue tip and ending in the lips, while moderate levels of the compound produced tingling, astringency, vibrating, and numbing from the tongue tip to the bilateral sides of the tongue, lips, palate, cheek mucosa, and surface of the tongue over time. There were significant differences in the maximum rate, peak time, and duration of any dominant sensation, as well as in the duration of sensation in the lips, tongue tip, and bilateral sides of the tongue. This study provides a dynamic profile of consuming pungent food, which provides a reference not only for the design of new food products with desirable pungency, but also as a scientific basis for the application of pungent compounds within the food and catering industry.

The Effect of Pungent and Tingling Compounds from Piper nigrum L. on Background K+ Currents.

Black peppercorns (Piper nigrum L.) elicit a pungent and tingling oral impression. Their pungency is partially explained by the agonist activity of some of their active principles, especially piperine, on TRP channels. However, we recently showed that piperine, as well as other pungent compounds, also possess a marked effect on two-pore domain (KCNK, K2P) K+ channels. Members of this family play a key role in maintaining the resting membrane potential of excitable cells. Interestingly, tingling compounds have been shown to induce neuronal excitation by inhibiting KCNK channels. We addressed the question of whether it was plausible that KCNK channels could constitute a physiologically relevant target for the sensory active compounds present in black peppercorns. Because previous studies have demonstrated that mouse trigeminal neurons respond to several pungent compounds, to which humans are also sensitive, we used a primary culture of mouse trigeminal neurons to investigate whether the effect of piperine on these cell types could also be mediated by KCNK channels. We observed that even in the presence of classical TRP-antagonists, piperine was still able to activate a fraction of trigeminal neurons. Furthermore, our results showed that piperine is capable of inducing neuronal depolarization by a mechanism that does not require extracellular Na+ or Ca2+. This depolarization was mediated by the inhibition of a background K+ conductance, most likely corresponding to the KCNK channels of the TASK subfamily. We then performed a screening with 12 other pungent and/or tingling chemosensates isolated from black peppercorns. These compounds were evaluated on Xenopus laevis oocytes expressing the human orthologues of KCNK3, KNCK9 and KCNK18, which we previously showed to be inhibited by piperine. Remarkably, almost all of the isolated chemosensates inhibited the basal activity of hKCNK3, with 1-(octadeca-2E,4E,13/12Z-trienoyl)pyrrolidine acting as one of the most potent natural blockers for hKCNK3 found to date. Our results suggest that KCNK channels, especially KCNK3, are likely to play a complementary role to TRP channels in the complex orosensory impression elicited by black peppercorns, while they also help to expand the pharmacological knowledge of KCNK channels.

6-shogaol, a neuroactive compound of ginger (jahe gajah) induced neuritogenic activity via NGF responsive pathways in PC-12 cells

BackgroundGinger is a popular spice and food preservative. The rhizomes of the common ginger have been used as traditional medicine to treat various ailments. 6-Shogaol, a pungent compound isolated from the rhizomes of jahe gajah (Zingiber officinale var officinale) has shown numerous pharmacological activities, including neuroprotective and anti-neuroinflammatory activities. The aim of this study was to investigate the potential of 6-shogaol to mimic the neuritogenic activity of nerve growth factor (NGF) in rat pheochromocytoma (PC-12) cells.MethodsThe cytotoxic effect of 6-shogaol was determined by 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The neuritogenic activity was assessed by neurite outgrowth stimulation assay while the concentration of extracellular NGF in cell culture supernatant was assessed by enzyme-linked immunosorbent assay (ELISA). Involvement of cellular signaling pathways, mitogen-activated protein kinase kinase/extracellular signal-regulated kinase1/2 (MEK/ERK1/2) and phosphoinositide-3-kinase/protein kinase B (PI3K/AKT) in 6-shogaol-stimulated neuritogenesis were examined by using specific pharmacological inhibitors.Results6-Shogaol (500 ng/ml) induced neuritogenesis that was comparable to NGF (50 ng/ml) and was not cytotoxic towards PC-12 cells. 6-Shogaol induced low level of NGF biosynthesis in PC-12 cells, showing that 6-shogaol stimulated neuritogenesis possibly by inducing NGF biosynthesis, and also acting as a substitute for NGF (NGF mimic) in PC-12 cells. The inhibitors of Trk receptor (K252a), MEK/ERK1/2 (U0126 and PD98059) and PI3K/AKT (LY294002) attenuated the neuritogenic activity of both NGF and 6-shogaol, respectively.ConclusionsThe present findings demonstrated that 6-shogaol induced neuritogenic activity in PC-12 cells via the activation MEK/ERK1/2 and PI3K/AKT signaling pathways. This study suggests that 6-shogaol could act as an NGF mimic, which may be beneficial for preventive and therapeutic uses in neurodegenerative diseases.

An R2R3-MYB Transcription Factor Regulates Capsaicinoid Biosynthesis.

Capsaicinoids are responsible for the hot taste of chili peppers. They are restricted to the genus Capsicum and are synthesized by the acylation of the aromatic compound vanillylamine (derived from the phenylpropanoid pathway) with a branched-chain fatty acid by the catalysis of the putative enzyme capsaicinoid synthase. R2R3-MYB transcription factors have been reported in different species of plants as regulators of structural genes of the phenylpropanoid pathway; therefore, we hypothesized that MYB genes might be involved in the regulation of the biosynthesis of pungent compounds. In this study, an R2R3-MYB transcription factor gene, designated CaMYB31, was isolated and characterized in Capsicum annuum 'Tampiqueño 74'. Bioinformatic analysis suggested that CaMYB31 could be involved in secondary metabolism, stress and plant hormone responses, and development. CaMYB31 expression analysis from placental tissue of pungent and nonpungent chili pepper fruits showed a positive correlation with the structural genes Ca4H, Comt, Kas, pAmt, and AT3 expression and also with the content of capsaicin and dihydrocapsacin during fruit development. However, CaMYB31 also was expressed in vegetative tissues (leaves, roots, and stems). Moreover, CaMYB31 silencing significantly reduced the expression of capsaicinoid biosynthetic genes and the capsaicinoid content. Additionally, CaMYB31 expression was affected by the plant hormones indoleacetic acid, jasmonic acid, salicylic acid, and gibberellic acid or by wounding, temperature, and light, factors known to affect the production of capsaicinoids. These findings indicate that CaMYB31 is indeed involved in the regulation of structural genes of the capsaicinoid biosynthetic pathway.

Experimental and computational approaches to reveal the potential of Ficus deltoidea leaves extract as α-amylase inhibitor

Ficus deltoidea leaves extract are known to have good therapeutic properties such as antioxidant, anti-inflammatory and anti-diabetic. We showed that 50% ethanol-water extract of F. deltoidea leaves and its pungent compounds vitexin and isovitexin exhibited significant (p < 0.05) α-amylase inhibition with IC50 (vitexin: 4.6 μM [0.02 μg/mL]; isovitexin: 0.06 μg/mL [13.8 μM] and DPPH scavenging with IC50 (vitexin: 92.5 μM [0.4 μg/mL]; isovitexin: 0.5 μg/mL [115.4 μM]). Additionally, molecular docking analysis confirmed that vitexin has a higher binding affinity (-7.54 kcal/mol) towards α-amylase compared to isovitexin (−5.61 kcal/mol). On the other hand, the molecular dynamics findings showed that vitexin-α-amylase complex is more stable during the simulation of 20 ns when compared to the isovitexin-α-amylase complex. Our results suggest that vitexin is more potent and stable against α-amylase enzyme, thus it could develop as a therapeutic drug for the treatment of diabetes.

Comparative evaluation of physical properties and volatiles profile of cabbages subjected to hot air and freeze drying

The aim of the present study was to evaluate the physical parameters, volatiles profile and sensory quality of the cabbage pieces subjected to hot air drying and freeze drying processes. Physical properties such as water activity, shrinkage, hardness, springiness, cohesiveness, chewiness, rehydration ratio and color measurements were measured using standard procedures while the volatile compounds were determined by the SPME-GC-MS method. The results showed that convective drying of cabbages lead to major adverse changes in physical and volatile compounds characteristics. Hot air and freeze drying of cabbages display different volatiles profile containing aldehydes, alcohols, terpenes, ketones and furans. Better retention of character impact cabbage green and pungent aroma compounds viz. allyl isothiocyanate, dimethyl sulfide, dimethyl disulfide, 1-octen-3-ol and (Z)-2-penten-1-ol was found in freeze dried cabbage. The presence of 3-(methylthio)-propyl isothiocyanate, methyl benzene isothiocyante and phenyl ethyl isothiocyanate is reported here for the first time in fresh cabbages. The flavor components of fresh cabbage were largely retained in the freeze dried product. Freeze drying also leads to positive sensory effects and better overall acceptability by consumers compared to the hot air dried product.

Inactivation in TRPV1 Ion Channels

TRPV1 are cation-permeable ion channels involved in several physiological processes. TRPV1 can be activated by several, very different, stimuli. Chief among these is a characteristic activation by temperatures in the noxious range and activation by several ligands, including capsaicin, the pungent compound that gives chilies their characteristic spiciness. Depolarizing voltages can also activate these channels, although with a very small voltage-dependence (the associated valence of activation is at most 1 elementary charge, eo). In the absence of any other ligands, voltage behaves as a “partial agonist”, producing a maximal open probability of less than 0.5 at extremely high voltages. Activation by voltage is more effective when combined with other activation modes, including activating by capsaicin and temperature. It has been previously shown that allosteric coupling models can describe this behavior, with independent voltage, temperature and ligand gating modules allostericaly coupled to a pore module. Here we show that in the presence of these activators, TRPV1 channels show a marked inactivation behavior induced by high voltages, which can be seen as time- and voltage-dependent reductions in the magnitude of the outward currents and can be explained by models with inactivation happening after the open state. High activating temperatures (47-60 oC) can also induce inactivation by itself, even at moderate voltages and this temperature-dependent inactivation seems to be an irreversible process. Inactivation of TRPV1 has not been previously described; although careful inspection of previously published TRPV1 current records show evidence of this phenomenon. This work supported by grants PAPIIT-DGAPA-UNAM No. IN209515 to LDI and No. IN200314 to TR and CONACYT Fronteras de la Ciencia No.77 to LDI and TR.

6-Paradol and 6-Shogaol, the Pungent Compounds of Ginger, Promote Glucose Utilization in Adipocytes and Myotubes, and 6-Paradol Reduces Blood Glucose in High-Fat Diet-Fed Mice.

The anti-diabetic activity of ginger powder (Zingiber officinale) has been recently promoted, with the recommendation to be included as one of the dietary supplements for diabetic patients. However, previous studies presented different results, which may be caused by degradation and metabolic changes of ginger components, gingerols, shogaols and paradols. Therefore, we prepared 10 ginger active components, namely 6-, 8-, 10-paradols, 6-, 8-, 10-shogaols, 6-, 8-, 10-gingerols and zingerone, and evaluated their anti-hyperglycemic activity. Among the tested compounds, 6-paradol and 6-shogaol showed potent activity in stimulating glucose utilization by 3T3-L1 adipocytes and C2C12 myotubes. The effects were attributed to the increase in 5′ adenosine monophosphate-activated protein kinase (AMPK) phosphorylation in 3T3-L1 adipocytes. 6-Paradol, the major metabolite of 6-shogaol, was utilized in an in vivo assay and significantly reduced blood glucose, cholesterol and body weight in high-fat diet-fed mice.

Combined treatment with zingerone and its novel derivative synergistically inhibits TGF-β1 induced epithelial-mesenchymal transition, migration and invasion of human hepatocellular carcinoma cells

The epithelial–mesenchymal transition (EMT) is an important cellular process during which polarized epithelial cells become motile mesenchymal cells, which promote cancer metastasis. Ginger, the rhizome of Zingiber officinale, is extensively used in cooking worldwide and also as a traditional medicinal herb with antioxidant, anti-inflammatory and anticancer properties. Several pungent compounds have been identified in ginger, including zingerone, which has anticancer potential. However, the role of zingerone in EMT is unclear. We investigated the synergistic effect of zingerone and its derivative on EMT. Transforming growth factor-beta 1 (TGF-β1) induces the EMT to promote hepatocellular carcinoma metastasis, including migration and invasion. To understand the repressive role of the combination of zingerone and its derivative (ZD 2) in hepatocellular carcinoma metastasis, we investigated the potential use of each compound of ginger, such as zingerone, ZD 2 and 6-shogaol, or the mixture of zingerone and ZD 2 (ZD 2-1) as inhibitors of TGF-β1 induced EMT development in SNU182 hepatocellular carcinoma cells in vitro. We show that ZD 2-1, but not zingerone, ZD 2 and 6-shogaol significantly increased expression of the epithelial marker E-cadherin and repressed Snail upregulation and expression of the mesenchymal marker N-cadherin during initiation of the TGF-β1 induced EMT. In addition, ZD 2-1 inhibited the TGF-β1 induced increase in cell migration and invasion of SNU182 hepatocellular carcinoma cells. Furthermore, ZD 2-1 significantly inhibited TGF-β1 regulated matrix metalloproteinase-2/9 and activation of Smad2/3. We also found that ZD 2-1 inhibited nuclear translocation of NF-κB, activation of p42/44 MAPK/AP1 signaling pathway in the TGF-β1 induced EMT. Our findings provide new evidence that combined treatment with ZD 2, novel zingerone derivative, and zingerone synergistically suppresses hepatocellular carcinoma metastasis in vitro by inhibiting the TGF-β1 induced EMT.

Evaporation of allyl isothiocyanate from clay minerals and organoclays

Allyl isothiocyanate (AITC), the major component in mustard oil, is an organosulfur volatile pungent compound classified as “generally regarded as safe”. Methods to slow its evaporation rate can increase its applicability as a natural and safe preservative in food industry and as a pesticide in agriculture. This study tested evaporation of AITC mixed with mineral oil and combined with clay minerals or smectite based organoclays. Raw smectites and halloysites did not influence the evaporation rate, whereas fibrous clays increased half-life time by 3–4 folds. Organoclays differed on their efficiency. An organoclays based on thiamine (B1 vitamin) adsorbed on montmorillonite exhibited the best behavior, increasing half-life time 10 times. Thus, the combination of mustard oil with such organoclay may offer an efficient and natural character preservative and pesticide.

6-Shogaol, an active compound of ginger, alleviates allergic dermatitis-like skin lesions via cytokine inhibition by activating the Nrf2 pathway

Allergic dermatitis (AD) clinically presents with skin erythematous plaques, eruption, and elevated serum IgE, and T helper cell type 2 and 1 (Th2 and Th1) cytokine levels. 6-Shogaol [1-(4-hydroxy-methoxyphenyl)-4-decen-one], a pungent compound isolated from ginger, has shown anti-inflammatory effects, but its inhibitory effects on AD are unknown. The aim of this study was to examine whether 6-shogaol inhibits AD-like skin lesions and their underlying mechanism in vivo and in vitro. An AD-like response was induced by tumor necrosis factor-α (TNF-α)+IFN-γ in human keratinocytes or by 2,4-dinitrochlorobenzene (DNCB) in mice. In vivo, 6-shogaol inhibited the development of DNCB-induced AD-like skin lesions and scratching behavior, and showed significant reduction in Th2/1-mediated inflammatory cytokines, IgE, TNF-α, IFN-γ, thymus and activation-regulated chemokine, IL-1, 4, 12, and 13, cyclooxygenase-2, and nitric oxide synthase levels. In vitro, 6-shogaol inhibited reactive oxygen species (ROS) and mitogen-activated protein kinases (MAPKs) signaling, and increased the levels of total glutathione, heme oxygenase-1, and quinone 1 via nuclear factor erythroid 2 related factor 2 (Nrf2) activation. 6-Shogaol can alleviate AD-like skin lesions by inhibiting immune mediators via regulating the ROS/MAPKs/Nrf2 signaling pathway, and may be an effective alternative therapy for AD.

Ionotropic Chemosensory Receptors Mediate the Taste and Smell of Polyamines.

The ability to find and consume nutrient-rich diets for successful reproduction and survival is fundamental to animal life. Among the nutrients important for all animals are polyamines, a class of pungent smelling compounds required in numerous cellular and organismic processes. Polyamine deficiency or excess has detrimental effects on health, cognitive function, reproduction, and lifespan. Here, we show that a diet high in polyamine is beneficial and increases reproductive success of flies, and we unravel the sensory mechanisms that attract Drosophila to polyamine-rich food and egg-laying substrates. Using a combination of behavioral genetics and in vivo calcium imaging, we demonstrate that Drosophila uses multisensory detection to find and evaluate polyamines present in overripe and fermenting fruit, their favored feeding and egg-laying substrate. In the olfactory system, two coexpressed ionotropic receptors (IRs), IR76b and IR41a, mediate the long-range attraction to the odor. In the gustatory system, multimodal taste sensation by IR76b receptor and GR66a bitter receptor neurons is used to evaluate quality and valence of the polyamine providing a mechanism for the fly’s high attraction to polyamine-rich and sweet decaying fruit. Given their universal and highly conserved biological roles, we propose that the ability to evaluate food for polyamine content may impact health and reproductive success also of other animals including humans.

QTLmapping for capsaicin and dihydrocapsaicin content in a population ofCapsicum annuum‘NB1’ × Capsicum chinense‘Bhut Jolokia’

AbstractCapsaicinoids are pungent compounds used for industrial and medical purposes including food, medicine and cosmetics. The Indian local variety ‘Bhut Jolokia’ (Capsicum chinenseJacq.) is one of the world's hottest chilli peppers. It produces more than one million Scoville heat units (SHUs) in total capsaicinoids. In this study, our goal was to identify quantitative trait loci (QTLs) responsible for the high content of capsaicin and dihydrocapsaicin in ‘Bhut Jolokia’.Capsicum annuum‘NB1’, a Korean pepper inbred line containing 14 000SHUs, was used as a maternal line. An F2population derived by crossing between ‘NB1’ and ‘Bhut Jolokia’ was generated to mapQTLs for capsaicinoids content. A total of 234 markers, including 201HRM, 21SSR, 2CAPSand 10 gene‐based markers of the capsaicinoid synthesis pathway, were mapped. The final map covered a total distance of 1175.2cMand contained 12 linkage groups corresponding to the basic chromosome number of chilli pepper. Capsaicin and dihydrocapsaicin content were analysed in 175 F2pepper fruits using theHPLCmethod. The maximum total capsaicinoids content was 1389 mg per 100g DW (dry weight), and the minimum content was 11 mg per 100g DW. TwoQTLs (qcap3.1andqcap6.1) for capsaicin content were identified onLG3 andLG6, and twoQTLs (qhdc2.1andqdhc2.2) for dihydrocapsaicin content were located onLG2. We did not detectQTLs for total capsaicinoids content. TheQTLpositions for capsaicin content were different from those for dihydrocapsaicin content. These results indicate that the complexity of selecting for more pungent chilli peppers must be considered in a chilli pepper breeding programme. TheQTL‐linked markers identified here will be helpful to develop more pungent pepper varieties from ‘Bhut Jolokia’, a very hot pepper.

Quantitation of Gingerols in Human Plasma by Newly Developed Stable Isotope Dilution Assays and Assessment of Their Immunomodulatory Potential.

In a pilot study with two volunteers, the main pungent and bioactive ginger (Zingiber officinale Roscoe) compounds, the gingerols, were quantitated in human plasma after ginger tea consumption using a newly established HPLC-MS/MS(ESI) method on the basis of stable isotope dilution assays. Limits of quantitation for [6]-, [8]-, and [10]-gingerols were determined as 7.6, 3.1, and 4.0 nmol/L, respectively. The highest plasma concentrations of [6]-, [8]-, and [10]-gingerols (42.0, 5.3, and 4.8 nmol/L, respectively) were reached 30-60 min after ginger tea intake. Incubation of activated human T lymphocytes with gingerols increased the intracellular Ca(2+) concentration as well as the IFN-γ secretion by about 20-30%. This gingerol-induced increase of IFN-γ secretion could be blocked by the specific TRPV1 antagonist SB-366791. The results of the present study point to an interaction of gingerols with TRPV1 in activated T lymphocytes leading to an augmentation of IFN-γ secretion.

Extracellular Sodium is Required for Temperature-Dependent Gating in TRPV1 Channels

The TRPV1 channel in sensory neurons integrates pain-producing stimuli, including noxious temperature, acidosis, pungent vanilloid compounds and pro-inflammatory lipids. Measurements of TRPV1 channel activity at extreme positive and negative voltages in the presence of other stimuli suggest that the channel has a unique opening transition that is allosterically modulated by independent stimulus-sensing domains. On the contrary, recently obtained near-atomic resolution structures of TRPV1 in different states suggest that different agonists promote distinct open states, by differentially modulating the inner pore gate or the selectivity filter. Finally, it has been proposed that the opening of the pore may confer the channel with high temperature-sensitivity. Here we show that extracellular sodium ions tune both temperature-dependent activation and inactivation in TRPV1 channels to maintain sensitivity to noxious stimuli at physiological temperatures. Exploration of temperature-dependent activation over a wide range of temperatures in the presence of distinct modulators demonstrates that the gating mechanism involves temperature-sensitive and -insensitive transitions that are allosterically coupled and differentially modified by sodium, pH, vanilloids and tarantula toxins. We observe that the channels exhibit non-maximal open probability and temperature-independent gating in the absence of external sodium or in the presence of double knot tarantula toxin DkTx, indicating that the opening transition is temperature-independent and supporting the modular allosteric view of this channel protein. This unique gating mechanism provides a framework for understanding how the temperature sensitivity of TRPV1 is tuned by a wide array of regulators.

Engineering Vanilloid-Sensitivity into the TRPV2 Channel

Abstract: The TRPV1 channel is a polymodal detector of noxious stimuli, including heat, acidosis, pungent vanilloid compounds and pro-inflammatory lipids. The gating mechanisms of the closely related TRPV2 channel are poorly understood because they are vanilloid-insensitive and only activated by extremely high temperatures above 50 °C. Recent cryo-EM structures of the TRPV1 channel identified a putative vanilloid binding pocket at the interface between S1-S4 domains and the pore domain. Here we use biophysical, biochemical, and electrophysiological approaches to investigate the vanilloid binding site and gating relationships between TRPV1 and TRPV2. Although the S1-S4 domain from TRPV1 can be expressed and purified in isolation of the pore domain, it does not bind vanilloids with high affinity. We identified four non-conserved residues in the vanilloid binding pocket of TRPV1 that when introduced into TRPV2 channels are sufficient to generate high-affinity vanilloid binding and robust channel activation. Taken together, our results support the identification of the vanilloid binding pocket in the TRPV1 structure, and suggest that TRPV1 and TRPV2 channels share common gating mechanisms even though their functional properties are distinct.

Inhibition of TRPV1 by an Unsaturated Fatty Acid

Some members of the TRP superfamily of ion channels are expressed in sensory neurons where they respond to noxious stimuli. TRPV1 channels mediate the response to a variety of stimuli such as high temperatures, tissue damage, bioactive lipids and exposure to pungent compounds such as capsaicin, all of which produce convergent activation and underlie the common perceptual experience of pain. To date, very few inhibitors of TRPV1's activity have been described and, in fact, most are synthetic in nature. We previously described that lysophosphatidic acid (LPA) is a bioactive lysophospholipid that directly activates TRPV1 and we also determined some of the structural features of different related lipids required for TRPV1 activation. During the screening of several fatty acids we found an unsaturated one that does not activate TRPV1 but rather inhibits its activation in response to capsaicin, acidic pH and LPA.Thus, we explored the mechanism of inhibition of TRPV1 by this molecule. We found that it acts from both the intra and extracellular sides by promoting the stabilization of a closed state of the channel by directly binding to the channel. The physiological response to this lipid is to inhibit the painful responses elicited by the injection of LPA into the paws of mice. These findings provide new insights into the molecular mechanisms involved in the inhibition of an important receptor of noxious stimuli.This work was supported by grants from “Programa de Apoyo a Proyectos de Investigacion e Innovacion Tecnologica (PAPIIT) IN200314 and Consejo Nacional de Ciencia y Tecnologia CB-2014-01-238399 (to T. R.), Programa de Apoyo a Proyectos de Investigacion e Innovacion Tecnologica (PAPIIT) IA202815 (to S.L.M.L).

Solid lipid microparticles produced by spray chilling technique to deliver ginger oleoresin: Structure and compound retention

Ginger oleoresin (GO) is frequently used as a flavor ingredient in various foods. Besides flavoring, its bioactive compounds are known for antimicrobial and antioxidant properties. In this study, we investigated the formation and characterization of solid lipid microparticles (SLMs) loaded with GO by the spray chilling technique. Mixtures composed of palmitic acid with oleic acid or palm fat were used as carriers. DSC and X-ray diffraction showed that the particle crystalline structure was decreased by oleic acid. Retention of pungent and volatile compounds was higher than 96% and 75%, respectively, in the best formulations. FTIR spectroscopy revealed no chemical interaction between GO and carriers. The particles presented a spherical shape and rough surface, and GO was dispersed over the entire particles, as shown by confocal microscopy. High volatile and pungent compound retention have shown that spray chilling can be a very promising technique for the production of SLM loaded with GO.

Influence of Dietary Capsaicin on Redox Status in Red Blood Cells During Human Aging.

Capsaicin (8-methyl-N-vanillyl-6-nonenamide) is a major pungent compound found in hot peppers of the plant genus Capsicum. In vitro effects of dietary capsaicin on redox status in red blood cells during human aging have been explored. Total antioxidant potential of capsaicin was evaluated using Ferric reducing ability of plasma (FRAP) assay. GSH was measured as per standard protocol. The in vitro effect of capsaicin was evaluated by incubation of the cells in the assay medium with 10(-5)M capsaicin (final concentration) for 60 min at 37°C. Treatment with capsaicin (10(-5)M) caused a significant (p < 0.01) increase in GSH level in all age groups. Reduced glutathione (GSH) / Oxidized glutathione (GSSG) ratio measures the redox status of the red blood cell. Significant increase in GSH level due to capsaicin, shift the GSH/GSSG ratio, thus alters the redox status of the cell. The results conclusively prove the efficacy of the antioxidant property of capsaicin and its role in modulating the redox status of red blood cells. This evidence suggests that dietary factors that act as antioxidants to increase GSH level may contribute to a protective effect against age related diseases. This antioxidant effect may, in part, explain the high consumption of capsicum in certain regions of the world.