Effects of capsaicin, green tea and CH-19 sweet pepper on appetite and energy intake in humans in negative and positive energy balance

Ecology, genetic diversity, and population structure among commercial varieties and local landraces of Capsicum spp. grown in northeastern states of India

Northeastern states of India are known for unique landraces of Capsicum spp. with geographical indications. However, little information is available about these valuable landraces of chillies. Surveys and collections were carried out in niche areas to find out their ecology and diversity through morphological traits and molecular analysis using microsatellite markers. Our result characterized the ecology of niche areas as cool (11.0°C-20.7°C) and humid (>60% relative humidity) climates for dalle-chilli (Capsicum annuum L.); mild-warm (12.2°C-28.6°C) and humid for king-chilli (C. chinense Jacq.); and cool to warm (11.3°C-33.1°C) and humid for bird's eye chilli (C. frutescens L.) during the crop period. The canonical correspondence analysis has shown the significant impact of temperature on the agro-morphological traits and distribution of the landraces in their niche areas. A wide variability was observed for different quantitative traits and yield attributing characters (fruit length, diameter, weight, and yield), showing high heritability (97.0%-99.0%), and genetic advance as a percentage of the mean (119.8%-434.0%). A total of 47 SSR markers used for the molecular analysis generated 230 alleles, ranging from 2 (HPMSE-7) to 10 (HPMSE-5), with an average of 4.89 alleles per locus. The average polymorphism information content was also high (0.61) and ranged from 0.20 (HPMSE-7) to 0.85 (CAMS-91). The observed average heterozygosity was lower than the expected value. Analysis of molecular variance has shown significant variation within (69%) and between (31%) of the populations of Capsicum spp. Based on Nei's genetic distance, bird's eye chilli and king-chilli were found to be closer to each other, whereas dalle-chilli, a tretraploid species, was closer to hot pepper (C. annuum). However, the flower size of dalle-chilli was large and found closer to king-chilli in color and differs from C. chinense due to the presence of calyx teeth. For quality traits, landraces king-chilli, dalle-chilli, and bird's eye chilli have shown 2.8, 2.0, and 1.4 times higher average capsaicin and 0.46, 0.25, and 0.22 times higher average oleoresin content over the hot pepper, respectively. The knowledge of ecology and diversity can be used in identifying new areas for production, selection of elite lines, conservation, and crop improvement.

Research progress in the role and mechanism of Leucine in regulating animal growth and development

Leucine, a branched-chain amino acid, is essential in regulating animal growth and development. Recent research has uncovered the mechanisms underlying Leucine's anabolic effects on muscle and other tissues, including its ability to stimulate protein synthesis by activating the mTORC1 signaling pathway. The co-ingestion of carbohydrates and essential amino acids enhances Leucine's anabolic effects. Moreover, Leucine has been shown to benefit lipid metabolism, and insulin sensitivity, making it a promising strategy for preventing and treating metabolic diseases, including type 2 diabetes and obesity. While emerging evidence indicates that epigenetic mechanisms may mediate Leucine's effects on growth and development, more research is needed to elucidate its mechanisms of action fully. Specific studies have demonstrated that Leucine promotes muscle growth and metabolic health in animals and humans, making it a promising therapeutic agent. However, it is essential to note that Leucine supplementation may cause digestive issues or interact with certain medications, and More study is required to determine definitively optimal dosages. Therefore, it is important to understand how Leucine interacts with other nutrients, dietary factors, and lifestyle habits to maximize its benefits. Overall, Leucine's importance in human nutrition is far-reaching, and its potential to prevent muscle loss and enhance athletic performance warrants further investigation.

Peppers and their constituents against obesity

Phytotherapy can be an efficient tool for prevention and treatment of disorders including obesity. The purpose of this narrative review is to summarize the available knowledge concerning the positive effects of peppers (Capsicum spp.) and their alkaloid capsaicin on human health, in particular on fat and obesity. Search for literature was performed in Medline/Pubmed, Web of Science and SCOPUS databases between the year 2000 and 2023. Words used to search were pepper, Capsicum, capsaicin, review, obesity, fat, weight loss and mechanisms. The available data demonstrate that both pepper extract and capsaicin can positively influence human health and treat several disorders. Moreover, they can reduce fat storage affecting brain centres responsible for the sensation of hunger, nutrient uptake by gastrointestinal tract, state of adipocytes, increase in carbohydrate and fat oxidation, metabolism and thermogenesis and other mechanisms. Therefore, despite some possible limitations, these substances could be useful for treatment of obesity.

Capsaicin regulates dyslipidemia by altering the composition of bile acids in germ-free mice

The improvement of lipid metabolism by capsaicin (CAP) has been extensively studied, mostly with respect to the vanilloid type 1 (TRPV1) ion channel and intestinal flora. In this study, a model was established in germ-free mice by using resiniferatoxin (RTX) to ablate TRPV1 ion channels. Bile acid composition, blood parameters, and colonic transcriptome analyses revealed that CAP could improve dyslipidemia caused by high-fat diet even in the absence of TRPV1 ion channels and intestinal flora. CAP fed to germ mice decreased the concentrations of low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), fasting blood glucose and fasting insulin, increased the concentration of high-density lipoprotein (HDL-C), and decreased the levels of plasma endotoxin and pro-inflammatory factor interleukin 6 (IL-6). Furthermore, CAP could affect both classical and alternative pathways of cholesterol conversion by changing the composition of bile acids, reducing the concentrations of glycocholic acid (GCA), ursodeoxycholic acid (UDCA) and glycochenodeoxycholic acid (GCDCA). First, changing the composition of bile acids inhibited the expression of colon Fgf15. CAP promoted the expression of Cyp7a1 (Cytochrome p450, family 7, subfamily a, and polypeptide 1) in the liver, and thus reduced TC and TG levels. In addition, it could change the composition of bile acids and increase the expression of Cyp7b1 (Cytochrome p450, family 7, subfamily b, and polypeptide 1) in the colon, increase Cyp7b1 protein in the liver and thus inhibit fat accumulation. In conclusion, CAP could alter the composition of bile acids and promote the conversion of cholesterol to bile acids, thereby improving lipid metabolism abnormalities caused by a high-fat diet.

Insights into the constellating drivers of satiety impacting dietary patterns and lifestyle

Food intake and body weight regulation are of special interest for meeting today's lifestyle essential requirements. Since balanced energy intake and expenditure are crucial for healthy living, high levels of energy intake are associated with obesity. Hence, regulation of energy intake occurs through short- and long-term signals as complex central and peripheral physiological signals control food intake. This work aims to explore and compile the main factors influencing satiating efficiency of foods by updating recent knowledge to point out new perspectives on the potential drivers of satiety interfering with food intake regulation. Human internal factors such as genetics, gender, age, nutritional status, gastrointestinal satiety signals, gut enzymes, gastric emptying rate, gut microbiota, individual behavioral response to foods, sleep and circadian rhythms are likely to be important in determining satiety. Besides, the external factors (environmental and behavioral) impacting satiety efficiency are highlighted. Based on mechanisms related to food consumption and dietary patterns several physical, physiological, and psychological factors affect satiety or satiation. A complex network of endocrine and neuroendocrine mechanisms controls the satiety pathways. In response to food intake and other behavioral cues, gut signals enable endocrine systems to target the brain. Intestinal and gastric signals interact with neural pathways in the central nervous system to halt eating or induce satiety. Moreover, complex food composition and structures result in considerable variation in satiety responses for different food groups. A better understanding of foods and factors impacting the efficiency of satiety could be helpful in making smart food choices and dietary recommendations for a healthy lifestyle based on updated scientific evidence.

The Utility of Capsicum annuum L. in Internal Medicine and In Dentistry: A Comprehensive Review

Capsaicin is a chili peppers extract, genus Capsicum, commonly used as a food spice. Since ancient times, Capsaicin has been used as a "homeopathic remedy" for treating a wild range of pathological conditions but without any scientific knowledge about its action. Several studies have demonstrated its potentiality in cardiovascular, nephrological, nutritional, and other medical fields. Capsaicin exerts its actions thanks to the bond with transient receptor potential vanilloid subtype 1 (TRPV1). TRPV1 is a nociceptive receptor, and its activation starts with a neurosensitive impulse, responsible for a burning pain sensation. However, constant local application of Capsaicin desensitized neuronal cells and leads to relief from neuropathic pain. In this review, we analyze the potential adjuvant role of Capsaicin in the treatment of different pathological conditions either in internal medicine or dentistry. Moreover, we present our experience in five patients affected by oro-facial pain consequent to post-traumatic trigeminal neuropathy, not responsive to any remedy, and successfully treated with topical application of Capsaicin. The topical application of Capsaicin is safe, effective, and quite tolerated by patients. For these reasons, in addition to the already-proven beneficial actions in the internal field, it represents a promising method for the treatment of neuropathic oral diseases.

An Overview of the TRP-Oxidative Stress Axis in Metabolic Syndrome: Insights for Novel Therapeutic Approaches

Metabolic syndrome (MS) is a complex pathology characterized by visceral adiposity, insulin resistance, arterial hypertension, and dyslipidaemia. It has become a global epidemic associated with increased consumption of high-calorie, low-fibre food and sedentary habits. Some of its underlying mechanisms have been identified, with hypoadiponectinemia, inflammation and oxidative stress as important factors for MS establishment and progression. Alterations in adipokine levels may favour glucotoxicity and lipotoxicity which, in turn, contribute to inflammation and cellular stress responses within the adipose, pancreatic and liver tissues, in addition to hepatic steatosis. The multiple mechanisms of MS make its clinical management difficult, involving both non-pharmacological and pharmacological interventions. Transient receptor potential (TRP) channels are non-selective calcium channels involved in a plethora of physiological events, including energy balance, inflammation and oxidative stress. Evidence from animal models of disease has contributed to identify their specific contributions to MS and may help to tailor clinical trials for the disease. In this context, the oxidative stress sensors TRPV1, TRPA1 and TRPC5, play major roles in regulating inflammatory responses, thermogenesis and energy expenditure. Here, the interplay between these TRP channels and oxidative stress in MS is discussed in the light of novel therapies to treat this syndrome.

Modulating effects of capsaicin on glucose homeostasis and the underlying mechanism

Abnormal glucose homeostasis is linked to a variety of metabolic syndromes, such as insulin resistance, obesity, type-2 diabetes mellitus, hypertension and cardiovascular diseases. Maintenance of normal glucose homeostasis is important for the body to keep normal biological functions. As the major bioactive ingredient in chili peppers responsible for the pungent flavor, capsaicin has been reported to effectively improve glucose homeostasis with low cytotoxicity. In this review, the modulating effects of capsaicin on glucose homeostasis in cell models, animal models and human trials are summarized through both TRPV1 dependent and TRPV1 independent pathways. The relevant molecular mechanisms underlying its regulatory effects are also evaluated. Understanding the effects and mechanisms of capsaicin on glucose metabolism could provide theoretical evidence for its application in the food and pharmaceutical industries.

Capsaicin and Its Effects on Body Weight

Capsaicin is a bioactive compound found in the fruits (i.e., peppers) of the plant genus Capsicum, which is widely used in many cultures. Besides many health effects of this compound, it can also be effective in body weight control through various mechanisms such as regulating lipolysis in adipocytes, increasing the feeling of satiety, stimulating energy expenditure, and reducing energy intake. This study investigated capsaicin and its effects on body weight control. In clinical studies, the amount of capsaicin affecting body weight loss differ. Longitudinal and randomized controlled studies are needed to explain the effects of capsaicin on body weight control.Key teaching points• Capsaicin can decrease hunger through hormones in the gastrointestinal tract.• Capsaicin can increase energy expenditure through brown adipose tissue.• Capsaicin can increase lipolysis in white adipose tissue.• More comprehensive studies are needed to clarify this issue.

Acute Response to Capsiate Supplementation at Rest and during Exercise on Energy Intake, Appetite, Metabolism, and Autonomic Function: A Randomized Trial

OBJECTIVE

The purpose of the present study was to examine the effect of capsiate supplementation on energy intake, self-reported appetite-related sensations, energy expenditure, fat oxidation, and autonomic parameters with and without an exercise intervention.

METHODS

Thirteen healthy men completed four randomized trials: two trials for the control condition (without exercise), one with capsiate supplementation (CTRL_cap) and one with a placebo (CTRL_pla), and two trials for the exercise condition, one with capsiate supplementation (EX_cap) and one with placebo (EX_pla). Exercise sessions were performed 150 min after the consumption of a standardized breakfast, and supplementation 115 min after consumption of breakfast. An ad libitum buffet was offered 200 min following the completion of the standardized breakfast, and energy intake (EI) and relative energy intake (REI) (relative energy intake = energy intake - energy expenditure related to exercise) were evaluated.

RESULTS

There were no significant effects on EI, self-reported appetite sensations, fat oxidation, and energy expenditure. REI was reduced in conditions involving EX when compared to CTRL. A low-frequency to high-frequency ratio for heart rate variability was higher in CTRL_cap (1.6 ± 1.1) vs. CTRL_pla (1.2 ± 0.9) (p = 0.025; d = 0.39).

CONCLUSION

Acute capsiate supplementation combined with aerobic exercise has limited effects on the examined variables (EI, REI, fat oxidation, energy expenditure, and autonomic parameters), while changes in the autonomic nervous system function in the absence of exercise may have occurred without influencing other variables.

CLINICAL TRIAL REGISTRATION

ensaiosclinicos.gov.br number, RBR-5pckyr https://ensaiosclinicos.gov.br/rg/RBR-5pckyr.

Sweet pepper and its principle constituent capsiate: functional properties and health benefits

Capsiate is a non-pungent analogue of capsaicin. It belongs to the family of capsinoids which are esters of vanillyl alcohol with fatty acids while capsaicin belongs to the family of capsaicinoids that are amides of vanillylamine with a variety of branched-chain fatty acids. While capsaicin is extensively reported for plethora of pharmacological actions, capsiate remains much less explored. Extracted from various species of Capsicum plant, the molecule has also been chemically synthesized via a number of synthetic and enzymatic routes. Based on its action on transient receptor potential vanilloid subfamily member 1 receptors, recent research has focused on its potential roles in treatment of obesity, metabolic disorders, cancer, cardiovascular disorders and gastro-intestinal disorders. Its toxicity profile has been reported to be much safe. The molecule, however, faces the challenge of low aqueous solubility and stability. It has been commercialized for its use as a weight loss supplement. However, the therapeutic potential of the compound which is much beyond boosting metabolism remains unexplored hitherto. This comprehensive review summarizes the studies demonstrating the therapeutic potential of capsiate in various pathological conditions. Discussed also are potential future directions for formulation strategies to develop efficient, safe and cost-effective dosage forms of capsiate to explore its role in various disease conditions. The databases investigated include Cochrane library, Medline, Embase, Pubmed and in-house databases. The search terms were "capsiate," "capsinoids," "thermogenesis," and their combinations. The articles were screened for relevance by going through their abstract. All the articles pertaining to physicochemical, physiological, pharmacological and therapeutic effects of capsiate have been included in the manuscript.

Use of dietary phytochemicals for inhibition of trimethylamine N-oxide formation

Trimethylamine-N-oxide (TMAO) has been reported as a risk factor for atherosclerosis development, as well as for other cardiovascular disease (CVD) pathologies. The objective of this review is to provide a useful summary on the use of phytochemicals as TMAO-reducing agents. This review discusses the main mechanisms by which TMAO promotes CVD, including the modulation of lipid and bile acid metabolism, and the promotion of endothelial dysfunction and oxidative stress. Current knowledge on the available strategies to reduce TMAO formation are discussed, highlighting the effect and potential of phytochemicals. Overall, phytochemicals (i.e., phenolic compounds or glucosinolates) reduce TMAO formation by modulating gut microbiota composition and/or function, inhibiting host's capacity to metabolize TMA to TMAO, or a combination of both. Perspectives for design of future studies involving phytochemicals as TMAO-reducing agents are discussed. Overall, the information provided by this review outlines the current state of the art of the role of phytochemicals as TMAO reducing agents, providing valuable insight to further advance in this field of study.

The Beneficial Effects of Red Sun-Dried Capsicum annuum L. Cv Senise Extract with Antioxidant Properties in Experimental Obesity are Associated with Modulation of the Intestinal Microbiota

SCOPE

Capsicum annuum L. cv Senise is a sweet pepper containing health promoting compounds that can be modified by ripening and drying. This study focuses on finding the peppers with the best antioxidant properties, which are evaluated on an experimental model of obesity.

METHODS AND RESULTS

Phytochemical profile and antioxidant activity are evaluated on several peppers obtained from the same cultivar at different ripening stages. Red sweet peppers show the highest content in polyphenols, β-carotene, lycopene, and capsinoids, and demonstrate the best antioxidant activity in vitro. Mice fed a high fat diet are orally treated with an extract from these peppers (Capsicum annuum extract [CAE]) (1, 10, and 25 mg/kg/day). It promotes weight loss and improves plasma markers related to glucose and lipid metabolisms. CAE also ameliorates obesity-associated systemic inflammation reducing the expression of pro-inflammatory cytokines in adipose and hepatic tissues and improving the expression of different markers involved in the gut epithelial barrier function. These effects are associated with a modulation of the intestinal microbiome, which appears altered.

CONCLUSIONS

The extract can be considered a new potential approach for the treatment of obesity, complementary to dietary restrictions.

Effects of Capsicum annuum supplementation on the components of metabolic syndrome: a systematic review and meta-analysis

Metabolic syndrome (MetS) has increasingly gained importance as the main risk factor for cardiovascular diseases and type II diabetes mellitus. Various natural compounds derived from plants are associated with beneficial effects on the incidence and progression of MetS. This study aimed to evaluate the effects of Capsicum annuum on factors related to MetS by assessing randomized controlled trials (written in English). We searched the online databases of PubMed, Embase, Google scholar, and Cochrane Library up to April 2020. ‘Patient/Population, Intervention, Comparison and Outcomes’ format was used to determine whether intervention with C. annuum supplementation compared with placebo supplementation had any effect on the components of MetS among participants. We considered standardized mean differences (SMD) with 95% confidence intervals (CI) as effect size measures using random-effects model. Analysis of the included 11 studies (n = 609) showed that C. annuum supplementation had significant effect on low density lipoprotein-cholesterol [SMD = − 0.39; 95% CI − 0.72, − 0.07; P = 0.02; prediction interval, − 1.28 to 0.50] and marginally significant effect on body weight [SMD = − 0.19; 95% CI − 0.40, 0.03; P = 0.09]. However, larger and well-designed clinical trials are needed to investigate the effects of C. annuum on MetS.

An Examination of a Novel Weight Loss Supplement on Anthropometry and Indices of Cardiovascular Disease Risk

PURPOSE

This study examined whether adding Dichrostachys glomerata (DG; 300 mg/d) to thermogenic supplements with (DG + C) and without (DG) caffeine and other nutrients affects weight loss, changes in body composition, and/or markers of health.

METHODS

Sixty-eight participants (female, 54%) were grouped in a double-blind, parallel, stratified random, placebo-controlled manner to supplement their diet with a placebo, DG, or DG + C for 12 weeks while maintaining their normal diet and physical activity. Diet, physical activity, body weight, body composition, anthropometric measures, resting energy expenditure, fasting blood samples, and questionnaires were obtained at 0, 4, 8, and 12 weeks and analyzed using general linear models with repeated measures. Data are reported as mean (±SD) and change from baseline (mean, 95% confidence interval) for weeks 4, 8, and 12, respectively, with p values showing changes from baseline.

RESULTS

DG treatment promoted significant but minor reductions in fat mass (-0.56 [-1.02, -0.14], p = 0.01; -0.63 [-1.23, -0.02], p = 0.04; -0.71 [-1.47, 0.09] kg, p = 0.08) and percent body fat (-0.46 [-0.96, -0.04], p = 0.07; -0.63 [-1.16, -0.10], p = 0.02; -0.78 [-1.45, 0.07] %, p = 0.03). There was some evidence that DG + C increased resting energy expenditure, decreased hunger, increased satiety, and improved sleep quality (diminished in DG + C). No other significant effects were observed.

CONCLUSIONS

Ingestion of thermogenic supplements containing DG (300 mg/d) with and without caffeine and other nutrients in overweight but otherwise healthy participants who did not alter diet or physical activity promoted clinically insignificant changes in body weight and composition.

Challenging energy balance - during sensitivity to food reward and modulatory factors implying a risk for overweight - during body weight management including dietary restraint and medium-high protein diets

Energy balance is a key concept in the etiology and prevalence of obesity and its co-morbidities, as well as in the development of possible treatments. If energy intake exceeds energy expenditure, a positive energy balance develops and the risk for overweight, obesity, and its co-morbidities increases. Energy balance is determined by energy homeostasis, and challenged by sensitivity to food reward, and to modulatory factors such as circadian misalignment, high altitude, environmental temperature, and physical activity. Food reward and circadian misalignment increase the risk for overweight and obesity, while high altitude, changes in environmental temperature, or physical activity modulate energy balance in different directions. Modulations by hypobaric hypoxia, lowering environmental temperature, or increasing physical activity have been hypothesized to contribute to body weight loss and management, yet no clear evidence has been shown. Dietary approach as part of a lifestyle approach for body weight management should imply reduction of energy intake including control of food reward, thereby sustaining satiety and fat free body mass, sustaining energy expenditure. Green tea catechins and capsaicin in red pepper in part meet these requirements by sustaining energy expenditure and increasing fat oxidation, while capsaicin also suppresses hunger and food intake. Protein intake of at least 0,8 g/kg body weight meets these requirements in that it, during decreased energy intake, increases food intake control including control of food reward, and counteracts adaptive thermogenesis. Prevention of overweight and obesity is underscored by dietary restraint, implying control of sensitivity to challenges to energy balance such as food reward and circadian misalignment. Treatment of overweight and obesity may be possible using a medium-high protein diet (0,8-1,2 g/kg), together with increased dietary restraint, while controlling challenges to energy balance.

Influence of a Novel Food-Grade Formulation of Red Chili Extract (Capsicum annum) on Overweight Subjects: Randomized, Double-Blinded, Placebo-Controlled Study

Capsaicinoids from pungent red chilies (Capsicum annum and Capsicum frutescens) have received significant attention as a natural supplement for the management of obesity. However, the consumption of chili extract at physiologically relevant dosage of capsaicinoids is a challenge owing to its pungency and gastrointestinal discomforts. The present study reports the systemic absorption, safety and influence of a novel, food-grade, and sustained-release formulation of capsaicinoids-rich red chili extract using fenugreek dietary fiber (Capsifen^®). Twenty-four healthy overweight subjects were randomized into placebo (n = 12) and Capsifen (n = 12) groups and supplemented with 200 mg × 1/day of Capsifen (4 mg capsaicinoids/day) for 28 days. Influence of Capsifen on eating behavior and appetite was followed by Three-Factor Eating Questionnaire (TFEQ) and Council of Nutrition Appetite Questionnaire (CNAQ), respectively. Consumption of Capsifen did not reveal any adverse events or deviations in hematology and biochemical parameters related to safety. However, a significant decrease in body weight (2.1%), w/h ratio (4%) and body mass index (BMI) (2.2%) were observed among Capsifen group when compared to placebo. The TFEQ and appetite analysis revealed a significant improvement in uncontrolled eating and reduction in appetite among Capsifen subjects. The UPLC-ESI-MS/MS analysis confirmed the absorption of capsaicinoids from CAP supplementation. The study further demonstrated the safety and tolerability of Capsifen at the investigational dosage. Thus, the significant reduction in anthropometric parameters such as body weight, w/h ratio, and BMI along with the improvement in eating behaviour as well as appetite, indicated the potential body weight management effect of Capsifen.

Dihydrocapsaicin-induced angiogenesis and improved functional recovery after cerebral ischemia and reperfusion in a rat model

This study investigated the long-term effects of dihydrocapsaicin (DHC)-induced angiogenesis and improved functional outcomes in cerebral ischemia and reperfusion (I/R) rats. Middle cerebral artery occlusion was induced in I/R rats for 2 h, followed by reperfusion. The animals were divided into three groups: sham, I/R + vehicle, and I/R + DHC (10 mg/kg body weight). Fourteen days after I/R injury, the DHC-treated I/R rats had decreased neurological deficit scores, infarct volume, and brain morphology changes. DHC-induced angiogenesis significantly increased the expression of angiogenic factor proteins, such as hypoxia inducible factor 1α (HIF-1α), vascular endothelial growth factor (VEGF), and matrix metalloprotease 9 (MMP-9), at 3 d and 14 d following I/R and also increased the expression of angiogenic inhibitors, such as angiopoietin 1 (Ang-1) and its receptor tyrosine kinase (Tie-2), at 14 d following reperfusion. DHC-mediated angiogenesis was confirmed by a significant increase in positive BrdU labeling that co-localized with the von Willebrand factor (an endothelial cell marker) at 14 d after I/R. Furthermore, rotarod and pole tests demonstrated that DHC promoted functional recovery when compared with the vehicle group. Thus, the results reveal that DHC mediates angiogenesis and functional recovery after an ischemic stroke.

Anti-obesity effects of capsaicin and the underlying mechanisms: a review

The mechanisms of anti-obesity effects of capsaicin in cell models, rodent models and human subjects were reviewed.

Mediterranean products as promising source of multi-target agents in the treatment of metabolic syndrome

Alteration of nutritional habits play an essential role on the risk of developing Metabolic Syndrome (MetS). Several epidemiological studies have shown that assuming diets rich of foods included in the Mediterranean diet (MetDiet) pattern like, such as olive oil, nuts, fruit, fiber, vegetables, wine and grain cereals has protective effects on the different risk factors characterizing the MetS. The beneficial effects of the MetDiet in the MetS are mainly due to the antioxidant and anti-inflammatory properties of the most abundant phytochemical components of such foods as polyphenols like resveratrol and oleuropein, allyl sulfides, ellagic acid, mono- and poly-unsaturated fatty acids (MUFA and PUFA), tocopherols and flavonoids like quercetin, which have shown positive results in the prevention of cardiovascular diseases (CVDs), with related risk factors, like hypertension, hypercholesterolemia and obesity. In this review, we highlighted the multi-target activities of the bioactive components contained in some foods typical of the Mediterranean area like olive oil, onion, liquorice, rosemary, oregano, hazelnut, pistachio, "Melannurca" apple, red wine, hot pepper, Citrus sp. fruits, saffron and garlic, with particular focus on their impact on health outcomes in relation to MetS main key factors, such as insulin resistance (IR) and type 2 diabetes mellitus (T2DM), endothelial dysfunctions, inflammatory response, oxidative stress and dyslipidaemic and hypercholesterolemic effects.

Appetite-Suppressing and Satiety-Increasing Bioactive Phytochemicals: A Systematic Review

The prevalence of obesity is increasing worldwide. Bioactive phytochemicals in food supplements are a trending approach to facilitate dieting and to improve patients' adherence to reducing food and caloric intake. The aim of this systematic review was to assess efficacy and safety of the most commonly used bioactive phytochemicals with appetite/hunger-suppressing and/or satiety/fullness-increasing properties. To be eligible, studies needed to have included at least 10 patients per group aged 18 years or older with no serious health problems except for overweight or obesity. Of those studies, 32 met the inclusion criteria, in which 27 different plants were tested alone or as a combination, regarding their efficacy in suppressing appetite/hunger and/or increasing satiety/fullness. The plant extracts most tested were derived from Camellia sinensis (green tea), Capsicum annuum, and Coffea species. None of the plant extracts tested in several trials showed a consistent positive treatment effect. Furthermore, only a few adverse events were reported, but none serious. The findings revealed mostly inconclusive evidence that the tested bioactive phytochemicals are effective in suppressing appetite/hunger and/or increasing satiety/fullness. More systematic and high quality clinical studies are necessary to determine the benefits and safety of phytochemical complementary remedies for dampening the feeling of hunger during dieting.

Assessment of Pharmacology, Safety, and Metabolic activity of Capsaicin Feeding in Mice

Capsaicin (CAP) activates transient receptor potential vanilloid subfamily 1 (TRPV1) to counter high-fat diet (HFD)-induced obesity. Several studies suggest that CAP induces the browning of white adipocytes in vitro or inguinal white adipose tissue (iWAT) in vivo. However, there is a lack of data on the dose-response for CAP to inhibit HFD-induced obesity. Therefore, we first performed experiments to correlate the effect of various doses of CAP to prevent HFD-induced weight gain in wild-type (WT) mice. Next, we performed a subchronic safety study in WT mice fed a normal chow diet (NCD ± CAP, 0.01% in NCD) or HFD ± CAP (0.01% in HFD) for eight months. We analyzed the expression of adipogenic and thermogenic genes and proteins in the iWAT from these mice, conducted histological studies of vital organs, measured the inflammatory cytokines in plasma and iWAT, and evaluated liver and kidney functions. The dose-response study showed that CAP, at doses above 0.001% in HFD, countered HFD-induced obesity in mice. However, no difference in the anti-obesity effect of CAP was observed at doses above 0.003% in HFD. Also, CAP, above 0.001%, enhanced the expression of sirtuin-1 and thermogenic uncoupling protein 1 (UCP-1) in the iWAT. Safety analyses suggest that CAP did not cause inflammation. However, HFD elevated plasma alanine aminotransferase and creatinine, caused iWAT hypertrophy and hepatic steatosis, and CAP reversed these. Our data suggest that CAP antagonizes HFD-induced metabolic stress and inflammation, while it does not cause any systemic toxicities and is well tolerated by mice.

In vitro effect of green tea and turmeric extracts on GLP-1 and CCK secretion: the effect of gastrointestinal digestion

Plant extract activity can be modified by the digestion process. In order to assess the satiety effect of green tea and turmeric extracts, an in vitro gastrointestinal digestion process was performed and the STC-1 cell line was used. The enteroendocrine cell line was incubated (for 30, 60 and 120 minutes) with the digested and non-digested extracts measuring the secretion of cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1) by enzyme-linked immunosorbent assay (ELISA). The release of satiety hormones by the STC-1 cells showed similar or higher results for plant extracts compared to the positive controls reported as satiatogenic (proteins and short chain fatty acids). For the non-digested samples, the largest amount of CCK and GLP-1 was found for turmeric, with 379 ± 46 pg ml-1 (60 min) and 347 ± 125 pg ml-1 (120 min) respectively. For the digested samples, the highest level of CCK was found for turmeric at 30 minutes (43.3 ± 11) and for GLP-1 by green tea at 120 minutes (165.7 ± 52). The in vitro gastrointestinal digestion process affects the satiety of plant extracts, increasing for green tea and decreasing for turmeric. Green tea showed the most stable satiating capacity after the in vitro digestion process and this may be useful for using it as a stable food supplement to reduce hunger associated with overweight and obesity.

Chinese Medicine in the Battle Against Obesity and Metabolic Diseases

Obesity is a multi-factor chronic disease caused by the mixed influence of genetics, environments and an imbalance of energy intake and expenditure. Due to lifestyle changes, modern society sees a rapid increase in obesity occurrence along with an aggravated risk of metabolic syndromes in the general population, including diabetes, hepatic steatosis, cardiovascular diseases and certain types of cancer. Although obesity has become a serious worldwide public health hazard, effective and safe drugs treating obesity are still missing. Traditional Chinese medicine (TCM) has been implicated in practical use in China for thousands of years and has accumulated substantial front line experience in treating various diseases. Compared to western medicine that features defined composition and clear molecular mechanisms, TCM is consisted with complex ingredients from plants and animals and prescribed based on overall symptoms and collective experience. Because of their fundamental differences, TCM and western medicine were once considered irreconcilable. However, nowadays, sophisticated isolation technologies and deepened molecular understanding of the active ingredients of TCM are gradually bridging the gap between the two, enabling the identification of active TCM components for drug development under the western-style paradigms. Thus, studies on TCM open a new therapeutic avenue and show great potential in the combat against obesity, though challenges exist. In this review, we highlight six key candidate substances derived from TCM, including artemisinin, curcumin, celastrol, capsaicin, berberine and ginsenosides, to review their recent discoveries in the metabolic field, with special focus on their therapeutic efficacy and molecular mechanisms in treating obesity and metabolic diseases. In addition, we discuss the translational challenges and perspectives in implementing modern Chinese medicine into the western pharmaceutical industry.

Capsaicin reverses the inhibitory effect of licochalcone A/β-Arbutin on tyrosinase expression in b16 mouse melanoma cells

Introduction:

Melanin is synthesized by melanocytes, which are located in the basal layer of the skin. After synthesis, melanin is further deposited on the surface of the skin to form black spots or chloasma. Tyrosinase is a rate-limiting enzyme that plays an important role in melanogenesis. Currently, there are many drugs that inhibit tyrosinase expression to further reduce melanogenesis. Nevertheless, some of these could reverse the pharmacological effect of other drugs, when used simultaneously.

Materials and Methods:

B16 mouse melanoma cells were treated with the tyrosinase inhibitors licochalcone A and β-arbutin, alone or in combination with capsaicin, an alkaloid found in peppers. Cytotoxicity, melanin content, and tyrosinase activity and expression were determined.

Results:

Licochalcone A/β-arbutin inhibited tyrosinase expression and further hindered melanin synthesis when applied individually to B16 mouse melanoma cells. However, licochalcone A/β-arbutin combined with 50 μmol/L capsaicin enhanced the expression of tyrosinase in these cells and further increased melanin content.

Conclusion:

Our data implied that capsaicin could reverse the inhibitory effect of licochalcone A/β-arbutin on tyrosinase expression in B16 mouse melanoma cells.

SUMMARY

B16 mouse melanoma cells were treated with the tyrosinase inhibitors licochalcone A and β-arbutin, alone or in combination with capsaicin, an alkaloid found in peppers. Cytotoxicity, melanin content, and tyrosinase activity and expression were determined. Licochalcone A/β-arbutin inhibited tyrosinase expression and further hindered melanin synthesis when applied individually to B16 mouse melanoma cells. However, licochalcone A/β-arbutin combined with 50 μmol/L capsaicin enhanced the expression of tyrosinase in these cells and further increased melanin content. Our research implied that capsaicin could reverse the inhibitory effect of licochalcone A/β-arbutin on tyrosinase expression in B16 mouse melanoma cells.

Abbreviations used: B16: B16 mouse melanoma cells; L-DOPA: 3, 4-L-dihydroxyphenylalanine; TYR: Tyrosinase; USP: United States Pharmacopeia; FBS: Fetal bovine serum; EDTA: Ethylenediaminetetraacetic acid; DMSO: Dimethyl sulfoxide; RPMI: Roswell Park Memorial Institute; MTT3: 4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide, NaOH: Sodium hydroxide; PBS: Phosphate-buffered saline; RIPA: Radio-immunoprecipitation assay; PMSF: Phenylmethanesulfonyl fluoride or phenylmethylsulfonyl fluoride; SDS: Sodium dodecyl sulfate, sodium salt; PVDF: Polyvinylidene fluoride; ECL: Enhanced chemiluminescence.

Involvement of TRPV1 Channels in Energy Homeostasis

The ion channel TRPV1 is involved in a wide range of processes including nociception, thermosensation and, more recently discovered, energy homeostasis. Tightly controlling energy homeostasis is important to maintain a healthy body weight, or to aid in weight loss by expending more energy than energy intake. TRPV1 may be involved in energy homeostasis, both in the control of food intake and energy expenditure. In the periphery, it is possible that TRPV1 can impact on appetite through control of appetite hormone levels or via modulation of gastrointestinal vagal afferent signaling. Further, TRPV1 may increase energy expenditure via heat production. Dietary supplementation with TRPV1 agonists, such as capsaicin, has yielded conflicting results with some studies indicating a reduction in food intake and increase in energy expenditure, and other studies indicating the converse. Nonetheless, it is increasingly apparent that TRPV1 may be dysregulated in obesity and contributing to the development of this disease. The mechanisms behind this dysregulation are currently unknown but interactions with other systems, such as the endocannabinoid systems, could be altered and therefore play a role in this dysregulation. Further, TRPV1 channels appear to be involved in pancreatic insulin secretion. Therefore, given its plausible involvement in regulation of energy and glucose homeostasis and its dysregulation in obesity, TRPV1 may be a target for weight loss therapy and diabetes. However, further research is required too fully elucidate TRPV1s role in these processes. The review provides an overview of current knowledge in this field and potential areas for development.

Polyphenols and their effects on diabetes management: A review

Background: Type 2 diabetes is a growing public health problem and is associated with increased morbidity and mortality. The worldwide prevalence of type 2 diabetes is rising. Polyphenols, such as flavonoids, phenolic acid, and stilbens, are a large and heterogeneous group of phytochemicals in plant-based foods. In this review, we aimed at assessing the studies on polyphenols and diabetes management. Methods: A literature search in the PubMed, EMBASE, Scopus, and ISI Web of Science databases was conducted to identify relevant studies published from 1986 to Jan 2017. Results: Several animal models and a limited number of human studies have revealed that polyphenols decrease hyperglycemia and improve acute insulin secretion and insulin sensitivity. The possible mechanisms include decrease in glucose absorption in the intestine, inhibition of carbohydrates digestion, stimulation of insulin secretion, modulation of glucose release from the liver, activation of insulin receptors and glucose uptake in insulin-sensitive tissues, modulation of intracellular signaling pathways, and gene expression. Conclusion: Growing evidence indicates that various dietary polyphenols may influence blood glucose at different levels and may also help control and prevent diabetes complication. However, we still need more clinical trials to determine the effects of polyphenols- rich foods, their effective dose, and mechanisms of their effects in managing diabetes.

Dihydrocapsaicin Attenuates Blood Brain Barrier and Cerebral Damage in Focal Cerebral Ischemia/Reperfusion via Oxidative Stress and Inflammatory

This study investigated the effect of dihydrocapsaicin (DHC) on cerebral and blood brain barrier (BBB) damage in cerebral ischemia and reperfusion (I/R) models. The models were induced by middle cerebral artery occlusion (MCAO) for 2 h followed by reperfusion. The rats were divided into five groups: sham, or control group; vehicle group; and 2.5 mg/kg, 5 mg/kg, and 10 mg/kg BW DHC-treated I/R groups. After 24 h of reperfusion, we found that DHC significantly reduced the area of infarction, morphology changes in the neuronal cells including apoptotic cell death, and also decreased the BBB damage via reducing Evan Blue leakage, water content, and ultrastructure changes, in addition to increasing the tight junction (TJ) protein expression. DHC also activated nuclear-related factor-2 (Nrf2) which involves antioxidant enzymes like superoxide dismutase (SOD) and glutathione peroxidase (GPx), and significantly decreased oxidative stress and inflammation via down-regulated reactive oxygen species (ROS), NADPH oxidase (NOX2, NOX4), nuclear factor kappa-beta (NF-ĸB), and nitric oxide (NO), including matrix metalloproteinases-9 (MMP-9) levels. DHC protected the cerebral and the BBB from I/R injury via attenuation of oxidative stress and inflammation. Therefore, this study offers to aid future development for protection against cerebral I/R injury in humans.

The Effect of Dietary Supplements Containing Green Tea, Capsaicin and Ginger Extracts on Weight Loss and Metabolic Profiles in Overweight Women: A Randomized Double-Blind Placebo-Controlled Clinical Trial

BACKGROUND

This study was conducted to determine the effects of dietary supplements containing green tea, capsaicin and ginger extracts on weight loss and metabolic profiles among overweight women.

METHODS

This randomized double-blind placebo-controlled clinical trial was implemented among 50 overweight women. Participants were randomly divided into 2 groups. Group A received dietary supplements containing 125 mg green tea, 25 mg capsaicin and 50 mg ginger extracts (n = 25) group B received placebos (n = 25) twice with lunch and twice with dinner daily for 8 weeks.

RESULTS

Compared with placebo, taking dietary supplements containing green tea, capsaicin and ginger resulted in a significant decrease in weight (-1.8 ± 1.5 vs. +0.4 ± 1.2 kg, respectively, p < 0.001) and body mass index (BMI; -0.7 ± 0.5 vs. +0.1 ± 0.5 kg/m2, respectively, p < 0.001). In addition, subjects who received green tea, capsaicin and ginger co-supplements had significantly decreased serum insulin concentrations (-2.6 ± 3.9 vs. -0.6 ± 2.0 µIU/mL, p = 0.02), homeostatic model of assessment for insulin resistance (-0.5 ± 0.8 vs. -0.05 ± 0.6, p = 0.01), and increased quantitative insulin sensitivity check index (+0.01 ± 0.01 vs. +0.001 ± 0.01, p = 0.008) and plasma glutathione (GSH) levels (+73.8 ± 120.6 vs. -28.3 ± 193.4 µmol/L, p = 0.03) compared with the placebo.

CONCLUSIONS

Our study indicated that taking green tea, capsaicin and ginger co-supplements for 8 weeks among overweight women had beneficial effects on weight, BMI, markers of insulin metabolism and plasma GSH levels.

Extraction, bioavailability, and bioefficacy of capsaicinoids

Capsaicinoids are active constituents responsible for the pungent and spicy flavor in chili peppers. During the past few decades, various extraction methods of capsaicinoids from peppers have been developed with high yields. Through biological studies, pharmacological benefits have been reported such as pain relief, antiinflammation, anticancer, cardioprotection, as well as weight loss. In this paper, the extraction methods and bioavailability of capsaicinoids are reviewed and discussed. In addition, the pharmacological effects and their underlying mechanisms are also studied.

Current Understanding of Antiobesity Property of Capsaicin

The capsaicin is an ingredient that we normally mix in food in many cultural cuisines even in fresh and dried production. Because of its anticancer, anticholesterolemic, antidiabetic, antihypertensive, anti-inflammatory, antimicrobial, and antioxidant properties, capsaicin is used worldwide. Moreover, capsaicin is also used for the protection of cardiovascular and hepatic diseases. The electronic databases PubMed, Scopus, Web of Science, Google Scholar, and ScienceDirect were searched since 2000 to present for antiobesity term. This review article is provided the update information about the antiobesity property and mechanism of capsaicin for further researches.

The enhanced anti-obesity effect and reduced gastric mucosa irritation of capsaicin-loaded nanoemulsions

Organogel-derived capsaicin nanoemulsions can inhibit diet-induced hepatic steatosis and reduce epididymal adipocyte size and tissue mass.

Chili pepper as a body weight-loss food

Chili has culinary as well as medical importance. Studies in humans, using a wide range of doses of chili intake (varying from a single meal to a continuous uptake for up to 12 weeks), concluded that it facilitates weight loss. In regard to this, the main targets of chili are fat metabolism, energy expenditure, and thermogenesis. To induce weight loss, the active substance of chili, capsaicin, activates Transient Receptor Potential Cation Channel sub-family V member 1 (TRPV1) channels) receptors causing an increase in intracellular calcium levels and triggering the sympathetic nervous system. Apart from TRPV1, chili directly reduces energy expenditure by activating Brown Adipose Tissue. Weight loss by chili is also the result of an improved control of insulin, which supports weight management and has positive effects for treatment for diseases like obesity, diabetes and cardiovascular disorders. This review summarizes the major pathways by which chili contributes to ameliorating parameters that help weight management and how the consumption of chili can help in accelerating weight loss through dietary modifications.

Capsaicin: Current Understanding of Its Mechanisms and Therapy of Pain and Other Pre-Clinical and Clinical Uses

In this review, we discuss the importance of capsaicin to the current understanding of neuronal modulation of pain and explore the mechanisms of capsaicin-induced pain. We will focus on the analgesic effects of capsaicin and its clinical applicability in treating pain. Furthermore, we will draw attention to the rationale for other clinical therapeutic uses and implications of capsaicin in diseases such as obesity, diabetes, cardiovascular conditions, cancer, airway diseases, itch, gastric, and urological disorders.

Phytochemicals in regulating fatty acid β-oxidation: Potential underlying mechanisms and their involvement in obesity and weight loss

Excessive accumulation of fat as the result of more energy intake and less energy expenditure is known as obesity. Lipids are essential components in the human body and are vital for maintaining homeostasis and physiological as well as cellular metabolism. Fatty acid synthesis and catabolism (by fatty acid oxidation) are normal part of basic fuel metabolism in animals. Fatty acids are degraded in the mitochondria by a biochemical process called β-oxidation in which two-carbon fragments are produced in each cycle. The increase in fatty acid β-oxidation is negatively correlated with body mass index. Although healthy life style, avoiding Western diet, dieting and strenuous exercise are the commonly used methods to lose weight, they are not considered a permanent solution in addition to risk attenuation of basal metabolic rate (BMR). Pharmacotherapy offers benefits of weight loss by altering the satiety and lowering absorption of fat from the food; however, its side effects may outweigh the benefits of weight loss. Alternatively, dietary phytochemicals and natural health products offer great potential as an efficient weight loss strategy by modulating lipid metabolism and/or increasing BMR and thermogenesis. Specifically, polyphenols such as citrus flavonoids, green tea epigallocatechin gallate, resveratrol, capsaicin and curcumin, have been reported to increase lipolysis and induce fatty acid β-oxidation through modulation of hormone sensitive lipase, acetyl-coA carboxylase, carnitine acyl transferase and peroxisome proliferator-activated receptor gamma coactivator-1. In this review article, we discuss selected phytochemicals in relation to their integrated functionalities and specific mechanisms for weight loss.

Effect of intragastric administration of capsaicin on gastric mucosal barrier in rats

AIM: To explore the effect of different doses of capsaicin (CAP) given for different durations on gastric mucosal barrier, liver and kidney histopathology, blood tests, and blood biochemistry in rats.

METHODS: Two hundred and forty SD rats were randomly divided into either an experimental group or a control group (group D). The experimental group was further divided into subgroups, which were given 0.1 mg/(kg•d) (group A), 1.0 mg/(kg•d) (group B), or 5.0 mg/(kg•d) CAP (group C) for 1 d, 7 d, 14 d or 28 d. Blood tests and blood biochemistry were measured. Gastric mucosa barrier and liver and kidney histopathology were assessed.

RESULTS: The status of rats in each group was good. The weight of all rats increased, and the weight of rats in group C increased relatively slowly, although there was no significant difference compared with group D. Rats of all groups had smooth gastric mucosa and had no erosion or bleeding. Guth score was 0 points for all rats. HE staining analysis showed that Masude score had no statistical differences among all groups (P > 0.05). Routine blood tests, AST, ALT and crea showed no statistical difference among each group. Serum CHOL and TG in groups B and C significantly decreased compared with group D. Liver and kidney histopathology was not affected in all groups.

CONCLUSION: Intragastric administration of low dose capsaicin had no significant impact on gastric mucosa barrier, liver and kidney histopathology, routine blood tests, AST, ALT and crea.

Variability in capsaicinoid content and Scoville heat ratings of commercially grown Jalapeño, Habanero and Bhut Jolokia peppers

The variability of capsaicinoid content of three common, commercially-available hot pepper varieties, namely Jalapeño, Habanero and Bhut Jolokia, was investigated. For each variety tested, ten peppers were acquired from each of ten different suppliers resulting in 100 peppers per variety that were individually analyzed. The results showed that different pepper varieties had different distribution types. The Habanero peppers showed a normal distribution; the Bhut Jolokia showed a skewed distribution and the Jalapeño peppers showed a very skewed distribution. The source of variability was also different; the Habaneros were very consistent within a given pepper supplier so most of the overall variation resulted from differences between suppliers. The Jalapeño peppers were the exact opposite with a very high degree of variability within a given supplier and relatively low variation between suppliers. A bootstrap statistical simulation was conducted on the data to suggest a minimum number of peppers to analyze to characterize the variation in a population. The simulations indicated that small sample sizes are effective at estimating the mean concentrations, but a sample size of ten or more is necessary to describe the population and capture the high-end tail of the distributions, which are the very hottest peppers.

Consumption of Chilies, but not Sweet Peppers, Is Positively Related to Handgrip Strength in an Adult Population

BACKGROUND

Chili consumption may have a beneficial effect on muscle strength in the general population. The aim of this study was to investigate the relationship between frequency of chili consumption and handgrip strength in adults.

DESIGN

Population-based cross-sectional study.

SETTING

This study used baseline data from the Tianjin Chronic Low-grade Systemic Inflammation and Health Cohort Study.

PARTICIPANTS

A total of 3 717 subjects were recruited to the study. Frequency of chili consumption during the previous month was assessed using a valid self-administered food frequency questionnaire. Analysis of covariance was used to examine the relationship between muscle strength and frequency of chili consumption. Handgrip strength was measured using a handheld digital dynamometer.

RESULTS

After adjustment for potential confounding factors, significant relationships were observed between different categories of chili consumption and handgrip strength in males, the means (95% confidence interval) for handgrip strength across chili consumption categories were 44.7 (42.1, 47.2) for < one time/week; 45.5 (42.9, 48.1) for one time/week; and 45.8 (43.3, 48.4) for ≥ 2-3 times/week (P for trend < 0.01). Similar results were not observed with sweet pepper consumption.

CONCLUSIONS

This study reveals a positive correlation between frequency of chili consumption and muscle strength in adult males. Further studies are necessary in order to determine whether there is a causal relationship between chili consumption frequency and muscle strength.