Dietary capsaicin and its anti-obesity potency: from mechanism to clinical implications

Hydroxycitric acid and capsaicin combination alleviates obesity-induced testicular apoptosis, oxidative stress and inflammation

Recent research in rodents suggests that oxidative stress, inflammation, and apoptosis in the testes caused by high-fat diets (HFD) are a cause of male infertility. To investigate the therapeutic efficacy of the combination of hydroxycitric acid and capsaicin (HCC) against male reproductive disorders, we developed an HFD-induced obese rat model. Rats received HFD supplementation for 21 weeks, which induced obesity. From week 16, HCC (100 mg/kg body weight) was administered to investigate its potential to treat testicular toxicity. According to the results of the current study, treatment of obese rats with HCC improved their sperm quality, increased the production of testosterone, follicle-stimulating hormone, and luteinizing hormone and significantly increased the activities of steroidogenic enzymes and corresponding mRNA levels. In addition, HCC decreased lipid peroxidation and nitric oxide levels in both spermatozoa and testes while increasing the expression of mRNA for the antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase in the testes, which in turn reduced oxidative stress in the testes. Moreover, after HCC treatment, testicular tissues showed a remarkable decrease in mRNA levels responsible for inflammation (TNF-α, IL-6, NF-κB) and apoptosis (Bax and Bcl-2). Our results suggest that HCC may alleviate obesity-induced male reproductive dysfunction by attenuating oxidative stress, inflammation, and apoptosis in the testes of HFD-induced obese male rats.

Does chili pepper consumption affect BMI and obesity risk? A cross-sectional analysis

Background

The effects of chili intake on overweight and obesity have attracted significant interest in recent years. This study aimed to investigate the correlation between chili consumption frequency, body mass index (BMI), and obesity prevalence in the American population.

Methods

Data from participants in National Health and Nutrition Examination Survey (NHANES) 2003-2006 were collected. We enrolled 6,138 participants with complete information on chili intake and BMI in this cross-sectional study. Multivariate logistic regression and sensitivity analyses were conducted to explore the relationship between chili intake frequency and BMI and obesity. Subgroup analyses and interaction tests were employed to assess the stability of the observed correlation.

Results

Increased chili consumption frequency was linked to higher BMI values and a greater prevalence of obesity. Compared to the non-consumption group, the highest frequency group had a multivariate-adjusted β of 0.71 (95% CI: 0.05, 1.38) for BMI and an OR of 1.55 (95% CI: 1.22, 1.97) for obesity in the fully adjusted model. This positive association between chili intake frequency and obesity was more pronounced in females and older adults (≥ 60 years old).

Conclusion

Our findings suggest a positive association between chili intake frequency and BMI and obesity in United States adults, suggesting that controlling chili intake frequency could potentially contribute to improved weight management in the general population.

The circadian rhythm: A new target of natural products that can protect against diseases of the metabolic system, cardiovascular system, and nervous system

BACKGROUND

The treatment of metabolic system, cardiovascular system, and nervous system diseases remains to be explored. In the internal environment of organisms, the metabolism of substances such as carbohydrates, lipids and proteins (including biohormones and enzymes) exhibit a certain circadian rhythm to maintain the energy supply and material cycle needed for the normal activities of organisms. As a key factor for the health of organisms, the circadian rhythm can be disrupted by pathological conditions, and this disruption accelerates the progression of diseases and results in a vicious cycle. The current treatments targeting the circadian rhythm for the treatment of metabolic system, cardiovascular system, and nervous system diseases have certain limitations, and the identification of safer and more effective circadian rhythm regulators is needed.

AIM OF THE REVIEW

To systematically assess the possibility of using the biological clock as a natural product target for disease intervention, this work reviews a range of evidence on the potential effectiveness of natural products targeting the circadian rhythm to protect against diseases of the metabolic system, cardiovascular system, and nervous system. This manuscript focuses on how natural products restore normal function by affecting the amplitude of the expression of circadian factors, sleep/wake cycles and the structure of the gut microbiota.

KEY SCIENTIFIC CONCEPTS OF THE REVIEW

This work proposes that the circadian rhythm, which is regulated by the amplitude of the expression of circadian rhythm-related factors and the sleep/wake cycle, is crucial for diseases of the metabolic system, cardiovascular system and nervous system and is a new target for slowing the progression of diseases through the use of natural products. This manuscript provides a reference for the molecular modeling of natural products that target the circadian rhythm and provides a new perspective for the time-targeted action of drugs.

A natural sustained-intestinal release formulation of red chili pepper extracted capsaicinoids (Capsifen®) safely modulates energy balance and endurance performance: a randomized, double-blind, placebo-controlled study

Introduction

Overweight and obesity are major public health concerns, with a sharp increase in prevalence over the last few decades. The primary cause is an imbalance between calorie intake and expenditure due to a rise in calorie-rich processed food and reduced physical activity. Energy balance in humans involves complex processes including thermogenesis, a crucial factor in regulating energy expenditure.

Methods

In this randomized, double-blinded, placebo-controlled three-arm three-sequence study, we investigated the efficacy of Capsifen® (CapF), a pungency-masked sustained-intestinal release formulation of red chili extract, on energy expenditure, fat oxidation, and endurance using the Quark C-PET system in healthy overweight participants, with and without exercise. In the study, 105 healthy participants were randomized to receive either placebo, CapF 100 mg/day, or CapF 200 mg/day for 28 days.

Results

CapF demonstrated a dose-dependent response to increased energy expenditure and fatty acid oxidation with a concomitant reduction in body weight. Both CapF 100 and CapF 200 also increased the time to exhaustion.

Discussion

These results demonstrate the plausible efficacy of CapF in energy expenditure and physical performance in otherwise healthy adults who have a high body mass index.

Clinical trial registration

https://ctri.nic.in/Clinicaltrials/pmaindet2.php?EncHid=MjQzNTg=&Enc=&userName=CTRI/2018/04/013157 dated 04 October 2018.

Limb, sex, but not acute dietary capsaicin, modulate the near-infrared spectroscopy-vascular occlusion test estimate of muscle metabolism

The downward slope during the near-infrared spectroscopy (NIRS)-vascular occlusion test (NIRS-VOT) is purported as a simplified estimate of metabolism. Whether or not the NIRS-VOT exhibits sex- or limb-specificity or may be acutely altered remains to be elucidated. Thus, we investigated if there is limb- or sex specificity in tissue desaturation rates (DeO2) during a NIRS-VOT, and if acute dietary capsaicin may alter this estimate of muscle metabolism. Young healthy men (n = 25, 21 ± 4 years) and women (n = 20, 20 ± 1 years) ingested either placebo or capsaicin, in a counterbalanced, single-blind, crossover design after which a simplified NIRS-VOT was conducted to determine the DeO2 (%/s), as an estimate of oxidative muscle metabolism, in both the forearm (flexors) and thigh (vastus lateralis). There was a significant limb effect with the quadriceps having a greater DeO2 than the forearm (-2.31 ± 1.34 vs. -1.78 ± 1.22%/s, p = 0.007, ηp 2 = 0.19). There was a significant effect of sex on DeO2 (p = 0.005, ηp 2 = 0.203) with men exhibiting a lesser DeO2 than women (-1.73 ± 1.03 vs. -2.36 ± 1.32%/s, respectively). This manifested in significant interactions of limb*capsaicin (p = 0.001, ηp 2 = 0.26) as well as limb*capsaicin*sex on DeO2 (p = 0.013, ηp 2 = 0.16) being observed. Capsaicin does not clearly alter O2-dependent muscle metabolism, but there was apparent limb and sex specificity, interacting with capsaicin in this NIRS-derived assessment.

Hepatoprotection of capsaicin in alcoholic and non-alcoholic fatty liver diseases

Alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD) are common causes of chronic liver disease that share the range of steatosis, steatohepatitis, fibrosis, cirrhosis, and finally, hepatocellular carcinoma. They are identified by the dysregulation of disease-specific signalling pathways and unique microRNAs. Capsaicin is an active ingredient of chilli pepper that acts as an agonist of transient receptor potential vanilloid subfamily 1. It seems that the protective role of capsaicin against NAFLD and ALD is linked to its anti-steatotic, antioxidant, anti-inflammatory, and anti-fibrotic effects. Capsaicin-induced inhibiting metabolic syndrome and gut dysbiosis and increasing bile acids production are also involved in its anti-NAFLD role. This review summarises the different molecular mechanisms underlying the protective role of capsaicin against NAFLD and ALD. More experimental studies are needed to clarify the effects of capsaicin on the expression of genes involved in hepatic lipid metabolism and hepatocytes apoptosis in NAFLD and ALD.

Natural compounds as obesity pharmacotherapies

Obesity has become a serious global public health problem, affecting over 988 million people worldwide. Nevertheless, current pharmacotherapies have proven inadequate. Natural compounds have garnered significant attention due to their potential antiobesity effects. Over the past three decades, ca. 50 natural compounds have been evaluated for the preventive and/or therapeutic effects on obesity in animals and humans. However, variations in the antiobesity efficacies among these natural compounds have been substantial, owing to differences in experimental designs, including variations in animal models, dosages, treatment durations, and administration methods. The feasibility of employing these natural compounds as pharmacotherapies for obesity remained uncertain. In this review, we systematically summarized the antiobesity efficacy and mechanisms of action of each natural compound in animal models. This comprehensive review furnishes valuable insights for the development of antiobesity medications based on natural compounds.

Lactational performance, enteric methane emission, and nutrient utilization of dairy cows supplemented with botanicals

The objective of this study was to evaluate lactational performance, enteric gas emissions, ruminal fermentation, nutrient use efficiency, milk fatty acid profile, and energy and inflammatory markers in blood of peak-lactation dairy cows fed diets supplemented with Capsicum oleoresin or a combination of Capsicum oleoresin and clove oil. A 10-wk randomized complete block design experiment was conducted with 18 primiparous and 30 multiparous Holstein cows. Cows were blocked based on parity, days in milk, and milk yield (MY), and randomly assigned to 1 of 3 treatments (16 cows/treatment): (1) basal diet (CON); (2) basal diet supplemented with 300 mg/cow per day of Capsicum oleoresin (CAP); and (3) basal diet supplemented with 300 mg/cow per day of a combination of Capsicum oleoresin and clove oil (CAPCO). Premixes containing ground corn (CON), CAP, or CAPCO were mixed daily with the basal diet at 0.8% of dry matter intake (DMI). Supplementation of the diet with CAP or CAPCO did not affect DMI, MY, milk components, and feed efficiency of the cows. Body weight (BW) was increased during the last 2 wk of the experiment by CAP and CAPCO, compared with CON. The botanicals improved BW gain (0.85 and 0.66 kg/d for CAP and CAPCO, respectively, compared with -0.01 kg/d for CON) and CAP enhanced the efficiency of energy utilization, compared with CON (94.5% vs. 78.4%, respectively). Daily CH4 emission was not affected by treatments, but CH4 emission yield (per kg of DMI) and intensity (per kg of MY) were decreased by up to 11% by CAPCO supplementation, compared with CON and CAP. A treatment × parity interaction indicated that the CH4 mitigation effect was pronounced in primiparous but not in multiparous cows. Ruminal molar proportion of propionate was decreased by botanicals, compared with CON. Concentrations of trans-10 C18:1 and total trans fatty acids in milk fat were decreased by CAP and tended to be decreased by CAPCO, compared with CON. Total-tract apparent digestibility of nutrients was not affected by treatments, except for a tendency for decreased starch digestibility in cows supplemented with botanicals. Blood concentrations of β-hydroxybutyrate, total fatty acids, and insulin were not affected by botanicals. Blood haptoglobin concentration was increased by CAP in multiparous but not in primiparous cows. Lactational performance of peak-lactation dairy cows was not affected by the botanicals in this study, but they appeared to improve efficiency of energy utilization and partitioned energy toward BW gain. In addition, CH4 yield and intensity were decreased in primiparous cows fed CAPCO, suggesting a potential positive environmental effect of the combination of Capsicum oleoresin and clove oil supplementation.

Anti-obesity Properties of Phytochemicals: Highlighting their Molecular Mechanisms against Obesity

Obesity is a complex, chronic and inflammatory disease that affects more than one-third of the world's population, leading to a higher incidence of diabetes, dyslipidemia, metabolic syndrome, cardiovascular diseases, and some types of cancer. Several phytochemicals are used as flavoring and aromatic compounds, also exerting many benefits for public health. This study aims to summarize and scrutinize the beneficial effects of the most important phytochemicals against obesity. Systematic research of the current international literature was carried out in the most accurate scientific databases, e.g., Pubmed, Scopus, Web of Science and Google Scholar, using a set of critical and representative keywords, such as phytochemicals, obesity, metabolism, metabolic syndrome, etc. Several studies unraveled the potential positive effects of phytochemicals such as berberine, carvacrol, curcumin, quercetin, resveratrol, thymol, etc., against obesity and metabolic disorders. Mechanisms of action include inhibition of adipocyte differentiation, browning of the white adipose tissue, inhibition of enzymes such as lipase and amylase, suppression of inflammation, improvement of the gut microbiota, and downregulation of obesity-inducing genes. In conclusion, multiple bioactive compounds-phytochemicals exert many beneficial effects against obesity. Future molecular and clinical studies must be performed to unravel the multiple molecular mechanisms and anti-obesity activities of these naturally occurring bioactive compounds.

Comprehensive insights into the multifaceted roles of the transient receptor potential vanilloid 1 channel in the digestive system

The transient receptor potential vanilloid (TRPV) channel, a family of calcium transporters comprising six distinct members (TRPV1-6), takes on a paramount role in maintaining intracellular Ca2+ homeostasis in mammalian cells. Notably, TRPV1, among its counterparts, has emerged as the subject of extensive scrutiny, owing to its pervasive presence in diverse cellular, tissue, and organ settings. This ubiquitous distribution underscores its fundamental involvement in the genesis of pain, making it a central focus in pain-related research. However, recent investigations have unveiled that TRPV1's functional significance transcends the realm of pain modulation, extending its influence to encompass a wide spectrum of physiological and pathological processes. The ambit of TRPV1's influence encompasses not only pain responses but also embraces the intricate domains of nervous system disorders, cancer metastasis, as well as afflictions pertaining to the skin and heart. Moreover, compelling evidence now demonstrates that TRPV1 also wields substantial sway in the domain of digestive diseases, further highlighting its versatility and far-reaching impact on human health. Therefore, this comprehensive review endeavors to delve into the multifaceted roles played by TRPV1 in the various organs constituting the digestive system.

Dietary Intake of Capsaicin and Its Association with Markers of Body Adiposity and Fatty Liver in a Mexican Adult Population of Tijuana

Background: Capsaicin (CAP) is the main chemical component responsible for the pungency (burning pain) of the chili plant (capsicum spp.), whose metabolic functions include energy balance and fatty acid oxidation. The aim of this study is to analyze the association of dietary capsaicin consumption with markers of adiposity and fatty liver in a Mexican adult population. Methods: This cross-sectional/analytical study recruited 221 subjects aged 18 to 65 years who were resident in the city of Tijuana, Baja California, Mexico. The daily CAP intake was analyzed through a validated chili/CAP consumption questionnaire. Anthropometric and biochemical measurements were performed following standardized protocols. Adjusted Pearson's correlations were applied to analyze the association of CAP with adiposity and fatty liver markers. Results: In this study, the daily average consumption of CAP was 152.44 mg. The dietary CAP consumption positively correlated with BMI (r = 0.179, p = 0.003), hip circumference (r = 0.176, p = 0.004) and body adiposity index (r = 0.181, p = 0.001. Likewise, the daily CAP intake positively correlated with hepatic steatosis index (r = 0.158, p = 0.004), fatty liver index (r = 0.141, p = 0.003) and lactate dehydrogenase (r = 0.194, p = 0.016) after statistical settings. Conclusions: The results of this study suggest positive associations between dietary CAP consumption and the markers of body adiposity and fatty liver in a Mexican adult population.

The effects of capsaicin intake on weight loss among overweight and obese subjects: a systematic review and meta-analysis of randomised controlled trials

Animal studies have shown that capsaicin plays a positive role in weight management. However, the results in human research are controversial. Therefore, the present systematic review and meta-analysis aimed to evaluate the effect of capsaicin on weight loss in adults. We searched PubMed, Embase, China Biomedical Literature Database (CBM), Cochrane library and clinical registration centre, identifying all randomised controlled trials (RCT) published in English and Chinese to 3 May 2022. A random-effect model was used to calculate the weighted mean difference (WMD) and 95 % CI. Heterogeneity between studies was assessed by the Cochran Q statistic and I-squared tests (I 2 ). Statistical analyses were performed using STATA version 15.1. P-values < 0·05 were considered as statistically significant. From 2377 retrieved studies, fifteen studies were finally included in the meta-analyses. Fifteen RCT with 762 individuals were included in our meta-analysis. Compared with the control group, the supplementation of capsaicin resulted in significant reduction on BMI (WMD: -0·25 kg/m2, 95 % CI = -0·35, -0·15 kg/m2, P < 0·05), body weight (BW) (WMD: -0·51 kg, 95 % CI = -0·86, -0·15 kg, P < 0·05) and waist circumference (WC) (WMD: -1·12 cm, 95 % CI = -2·00, -0·24 cm, P < 0·05). We found no detrimental effect of capsaicin on waist-to-hip ratio (WMD: -0·05, 95 % CI = -0·17, 0·06, P > 0·05). The current meta-analysis suggests that capsaicin supplementation may have rather modest effects in reducing BMI, BW and WC for overweight or obese individuals.

Capsaicin suppresses the migration and invasion of human nasopharyngeal carcinoma cells through the modulation of mTOR signaling pathway

Nasopharyngeal carcinoma (NPC), a malignancy of the nasopharynx, is prevalent in Southeast Asia and Southern China. The prognosis of NPC is poor and local recurrence and metastasis often occur. Capsaicin (tran-8-methyl-N-vanillyl-6-nonenamide), a pungent constituent of hot chili peppers, shows anti-cancer activities such as anti-proliferation and anti-metastasis. Currently, the role of capsaicin in cell metastasis of NPC is not well understood. We tested whether capsaicin has anti-metastatic activity in NPC cell lines. Capsaicin suppressed cell proliferation in dose-dependent manner. Moreover, capsaicin inhibited cell metastasis as shown by wound healing assay and decreased the expressions of MMP-2 and MMP-9. In addition, the phosphorylation of mTOR was downregulated by capsaicin. Combination of capsaicin and rapamycin (mTOR inhibitor) treatments led to increasing of anti-growth and anti-metastatic activities. Therefore, capsaicin has potential to be used as an optional therapeutic drug for treatment of NPC.

Drosophila melanogaster as a Translational Model System to Explore the Impact of Phytochemicals on Human Health

Fruits, vegetables, and spices are natural sources of bioactive phytochemicals, such as polyphenols, carotenoids, flavonoids, curcuminoids, terpenoids, and capsaicinoids, possessing multiple health benefits and relatively low toxicity. These compounds found in the diet play a central role in organism development and fitness. Given the complexity of the whole-body response to dietary changes, invertebrate model organisms can be valuable tools to examine the interplay between genes, signaling pathways, and metabolism. Drosophila melanogaster, an invertebrate model with its extensively studied genome, has more than 70% gene homology to humans and has been used as a model system in biological studies for a long time. The notable advantages of Drosophila as a model system, such as their low maintenance cost, high reproductive rate, short generation time and lifespan, and the high similarity of metabolic pathways between Drosophila and mammals, have encouraged the use of Drosophila in the context of screening and evaluating the impact of phytochemicals present in the diet. Here, we review the benefits of Drosophila as a model system for use in the study of phytochemical ingestion and describe the previously reported effects of phytochemical consumption in Drosophila.

The use of cellulose, chitosan and hyaluronic acid in transdermal therapeutic management of obesity: A review

Obesity is a clinical condition with rising popularity and detrimental impacts on human health. According to the World Health Organization, obesity is the sixth most common cause of death worldwide. It is challenging to combat obesity because medications that are successful in the clinical investigation have harmful side effects when administered orally. The conventional approaches for treating obesity primarily entail synthetic compounds and surgical techniques but possess severe adverse effects and recurrences. As a result, a safe and effective strategy to combat obesity must be initiated. Recent studies have shown that biological macromolecules of the carbohydrate class, such as cellulose, hyaluronic acid, and chitosan, can enhance the release and efficacy of medications for obesity but due to their short biological half-lives and poor oral bioavailability, their distribution rate is affected. This helps to comprehend the need for an effective therapeutic approach via a transdermal drug delivery system. This review focuses on the transdermal administration, utilizing cellulose, chitosan, and hyaluronic acid via microneedles, as it offers a promising solution to overcome existing therapy limitations in managing obesity and it also highlights how microneedles can effectively deliver therapeutic substances through the skin's outer layer, bypassing pain receptors and specifically targeting adipose tissue.

Plant-Derived Nutraceuticals Involved in Body Weight Control by Modulating Gene Expression

Obesity is the most prevalent health problem in the Western world, with pathological body weight gain associated with numerous co-morbidities that can be the main cause of death. There are several factors that can contribute to the development of obesity, such as diet, sedentary lifestyle, and genetic make-up. Genetic predispositions play an important role in obesity, but genetic variations alone cannot fully explain the explosion of obesity, which is why studies have turned to epigenetics. The latest scientific evidence suggests that both genetics and environmental factors contribute to the rise in obesity. Certain variables, such as diet and exercise, have the ability to alter gene expression without affecting the DNA sequence, a phenomenon known as epigenetics. Epigenetic changes are reversible, and reversibility makes these changes attractive targets for therapeutic interventions. While anti-obesity drugs have been proposed to this end in recent decades, their numerous side effects make them not very attractive. On the other hand, the use of nutraceuticals for weight loss is increasing, and studies have shown that some of these products, such as resveratrol, curcumin, epigallocatechin-3-gallate, ginger, capsaicin, and caffeine, can alter gene expression, restoring the normal epigenetic profile and aiding weight loss.

Effects of spicy food consumption on overweight/obesity, hypertension and blood lipids in China: a meta-analysis of cross-sectional studies

BACKGROUND AND OBJECTIVES

Effect of spicy food consumption on health has attracted widespread attention in recent years. However, the relationships between spicy food intake and overweight/obesity, hypertension and blood lipid levels remain unclear. A meta-analysis of available observational studies was conducted in order to explore the associations.

METHODS

PubMed, Embase, Cochrane Library and Web of science databases were searched for studies published up to 10 August 2021 without language limitation. The fixed and random effects models were selected to aggregate the effect sizes and 95% confidence intervals (CIs) in this study.

RESULTS

A total of nine observational studies involving 189,817 participants were included. Results from this meta-analysis showed that the highest category of spicy food intake significantly increased the risk of overweight/obesity (pooled Odds Ratio (OR): 1.17; 95% CI: 1.07, 1.28; P < 0.001), compared with the lowest category of spicy food intake. Conversely, a remarkable negative association was observed between the highest category of spicy food intake and hypertension (pooled OR: 0.87; 95% CI: 0.81, 0.93; P = 0.307). In addition, the highest category of spicy food intake increased the level of low density lipoprotein cholesterol (LDL-C) (weighted mean difference (WMD): 0.21; 95% CI: 0.02, 0.39; P = 0.040), and reduced high density lipoprotein cholesterol level (HDL-C) (WMD: -0.06; 95% CI: -0.10, -0.02; P = 0.268) concentrations, but it was not related to total cholesterol (TC) (WMD: 0.09; 95% CI: -0.08, 0.26; P = 0.071) and triglyceride (TG) (WMD: -0.08; 95% CI: -0.19, 0.02; P = 0.333)] levels.

CONCLUSION

Spicy food intake may have a beneficial effect on hypertension, but adversely affect overweight/obesity, as well as blood lipid levels. However, the results should be interpreted cautiously because the present analyses were based on only observational studies and not intervention studies. More large and high-quality studies in different populations will be needed to verify these associations in the future.

Capsaicin and Zinc Signalling Pathways as Promising Targets for Managing Insulin Resistance and Type 2 Diabetes

The global burden of type 2 diabetes (T2DM) has led to significant interest in finding novel and effective therapeutic targets for this chronic disorder. Bioactive food components have effectively improved abnormal glucose metabolism associated with this disease. Capsaicin and zinc are food components that have shown the potential to improve glucose metabolism by activating signalling events in the target cells. Capsaicin and zinc stimulate glucose uptake through the activation of distinct pathways (AMPK and AKT, respectively); however, calcium signal transduction seems to be the common pathway between the two. The investigation of molecular pathways that are activated by capsaicin and zinc has the potential to lead to the discovery of new therapeutic targets for T2DM. Therefore, this literature review aims to provide a summary of the main signalling pathways triggered by capsaicin and zinc in glucose metabolism.

Cannabidiol modulates contextual fear memory consolidation in animals with experimentally induced type-1 diabetes mellitus

OBJECTIVES

In view of the neuroprotective characteristic of cannabidiol (CBD) and its beneficial action on aversive memory in non-diabetic animals, we aimed to investigate in animals with experimentally induced type-1 diabetes mellitus (T1DM) whether CBD treatment would be able to impair the contextual fear memory consolidation, its generalisation and whether the effect would be lasting. We also investigated the CBD effect on anxiety-like responses.

METHODS

After T1DM induction, animals received single or more prolonged treatment with CBD and were submitted to the contextual fear conditioning test. As expression of activity-regulated cytoskeletal-associated (Arc) protein is necessary for memory consolidation, we evaluated its expression in the dorsal hippocampus (DH). For evaluating anxiety-related responses, animals were submitted to the elevated plus maze test (EPMT), in which the time and number of entries in the open arms were used as anxiety index.

RESULTS

A single injection of CBD impaired the contextual fear memory consolidation and its generalisation, which was evaluated by exposing the animal in a neutral context. This single injection was able to reduce the elevated expression of Arc in the DH from these animals. Interestingly, more prolonged treatment with CBD also impaired the persistence of context-conditioned fear memory and induced an anxiolytic-like effect, as the treated group spent more time in the open arms of the EPMT.

CONCLUSION

CBD interferes with contextual fear memory and the dosage regimen of treatment seems to be important. Moreover, we cannot rule out the involvement of emotional aspects in these processes related to fear memory.

Pharmacological Treatments and Natural Biocompounds in Weight Management

The obesity pandemic is one of society’s most urgent public health concerns. One-third of the global adult population may fall under obese or overweight by 2025, suggesting a rising demand for medical care and an exorbitant cost of healthcare expenditure in the coming years. Generally, the treatment strategy for obese patients is largely patient-centric and needs dietary, behavioral, pharmacological, and sometimes even surgical interventions. Given that obesity cases are rising in adults and children and lifestyle modifications have failed to produce the desired results, the need for medical therapy adjunct to lifestyle modifications is vital for better managing obesity. Most existing or past drugs for obesity treatment target satiety or monoamine pathways and induce a feeling of fullness in patients, while drugs such as orlistat are targeted against intestinal lipases. However, many medications targeted against neurotransmitters showed adverse events in patients, thus being withdrawn from the market. Alternatively, the combination of some drugs has been successfully tested in obesity management. However, the demand for novel, safer, and more efficacious pharmaceutical medicines for weight management does exist. The present review elucidates the current understanding of the available anti-obesity medicines of synthetic and natural origin, their main mechanisms of action, and the shortcomings associated with current weight management drugs.

Anti-Inflammatory and Antioxidative Phytogenic Substances against Secret Killers in Poultry: Current Status and Prospects

Chronic stress is recognized as a secret killer in poultry. It is associated with systemic inflammation due to cytokine release, dysbiosis, and the so-called leaky gut syndrome, which mainly results from oxidative stress reactions that damage the barrier function of the cells lining the gut wall. Poultry, especially the genetically selected broiler breeds, frequently suffer from these chronic stress symptoms when exposed to multiple stressors in their growing environments. Since oxidative stress reactions and inflammatory damages are multi-stage and long-term processes, overshooting immune reactions and their down-stream effects also negatively affect the animal's microbiota, and finally impair its performance and commercial value. Means to counteract oxidative stress in poultry and other animals are, therefore, highly welcome. Many phytogenic substances, including flavonoids and phenolic compounds, are known to exert anti-inflammatory and antioxidant effects. In this review, firstly, the main stressors in poultry, such as heat stress, mycotoxins, dysbiosis and diets that contain oxidized lipids that trigger oxidative stress and inflammation, are discussed, along with the key transcription factors involved in the related signal transduction pathways. Secondly, the most promising phytogenic substances and their current applications to ameliorate oxidative stress and inflammation in poultry are highlighted.

Mitochondrial Energy Metabolism in the Regulation of Thermogenic Brown Fats and Human Metabolic Diseases

Brown fats specialize in thermogenesis by increasing the utilization of circulating blood glucose and fatty acids. Emerging evidence suggests that brown adipose tissue (BAT) prevents the incidence of obesity-associated metabolic diseases and several types of cancers in humans. Mitochondrial energy metabolism in brown/beige adipocytes regulates both uncoupling protein 1 (UCP1)-dependent and -independent thermogenesis for cold adaptation and the utilization of excess nutrients and energy. Many studies on the quantification of human BAT indicate that mass and activity are inversely correlated with the body mass index (BMI) and visceral adiposity. Repression is caused by obesity-associated positive and negative factors that control adipocyte browning, de novo adipogenesis, mitochondrial energy metabolism, UCP1 expression and activity, and noradrenergic response. Systemic and local factors whose levels vary between lean and obese conditions include growth factors, inflammatory cytokines, neurotransmitters, and metal ions such as selenium and iron. Modulation of obesity-associated repression in human brown fats is a promising strategy to counteract obesity and related metabolic diseases through the activation of thermogenic capacity. In this review, we highlight recent advances in mitochondrial metabolism, thermogenic regulation of brown fats, and human metabolic diseases.

Chili pepper preference development and its impact on dietary intake: A narrative review

A preference for chili pepper can be an acquired taste. The contrast between a chili lover and a hater illustrates the complexities involved in forming an appreciation for food that evokes a fiery pain sensation. This narrative review aims to understand the factors behind chili pepper preference formation across the life course and how individual chili pepper preferences can impact eating behaviors and dietary intake. This review was conducted using three databases, yielding 38 included articles. Results suggest five determinants of chili pepper preferences: culture, exposure, gender, genetics, and personality. Collective findings indicate that the strongest influences on preference acquisition include the individual environment from childhood to adulthood and repeated exposure to spicy flavors. With frequent exposure to spicy food, the perceived burn becomes less intense. Culture also influences exposure to chili peppers, with the highest consumption patterns seen within Mexico and some Asia countries. Additionally, males reported having a stronger preference for spicy foods than females. Twin studies illustrated that genetics influenced spicy taste preferences, underscoring the complexity of developing individual taste preferences. As for the impact of capsaicin-containing food on individual eating behaviors and dietary behaviors, appetite effects depend on the dose of capsaicin consumed, but three studies found a change in sensory desires for sweet and fatty foods after finishing a capsaicin-containing dish. Inconsistent results were reported for chili pepper's effects on hunger and satiety after consumption, but changes in specific food desires were observed. The impact of chili pepper on appetite and calories consumed was inconsistent, but the greater amount of capsaicin ingested, the greater the effect. Capsaicin's potential to be used for weight control needs to be further reviewed. In conclusion, evidence suggests that chili pepper preferences may be linked to innate and environmental aspects such as an individual's culture, gender, and genetics. Extrinsic factors like repeated exposure may increase the liking for spicy foods.

Integrative proteomics and metabolomics of Guizhou Miao Sour Soup affecting simple obese rats

Miao Sour Soup (MSS) is a fermented product from the Qiandongnan region of Guizhou Province, which enrich many beneficial ingredients and is widely consumed in the whole China. Fermented food is beneficial to physical health with the potential positive regulating affection on simple obesity. In this study, we analyzed the mechanism of action of MSS to prevent simple obesity induced by high-fat diet by proteomics and metabolomics. Quantitative proteomics with tandem mass tagging labeling and liquid chromatography-mass spectrometry was used to analyze the changes of liver proteins and metabolites after the MSS intervention. MSS intervention upregulated 33 proteins and 9 metabolites and downregulated 19 proteins and 10 metabolites. Bioinformatics analysis showed that MSS could prevent simple obesity by acting on the PPAR signaling pathway, retinol metabolism, fatty acid β-oxidation, fatty acid degradation, fatty acid biosynthesis, glycine, serine and threonine metabolism, pyruvate metabolism, citrate cycle (TCA cycle) and other signaling pathways. This study provides new insights into the use of MSS to prevent simple obesity caused by high-fat diets and the search for healthy eating patterns with MSS.

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.

Peppers in Diet: Genome-Wide Transcriptome and Metabolome Changes in Drosophila melanogaster

The habanero pepper (Capsicum chinense) is an increasingly important spice and vegetable crop worldwide because of its high capsaicin content and pungent flavor. Diets supplemented with the phytochemicals found in habanero peppers might cause shifts in an organism’s metabolism and gene expression. Thus, understanding how these interactions occur can reveal the potential health effects associated with such changes. We performed transcriptomic and metabolomic analyses of Drosophila melanogaster adult flies reared on a habanero pepper diet. We found 539 genes/59 metabolites that were differentially expressed/accumulated in flies fed a pepper versus control diet. Transcriptome results indicated that olfactory sensitivity and behavioral responses to the pepper diet were mediated by olfactory and nutrient-related genes including gustatory receptors (Gr63a, Gr66a, and Gr89a), odorant receptors (Or23a, Or59a, Or82a, and Orco), and odorant-binding proteins (Obp28a, Obp83a, Obp83b, Obp93a, and Obp99a). Metabolome analysis revealed that campesterol, sitosterol, and sucrose were highly upregulated and azelaic acid, ethyl phosphoric acid, and citric acid were the major metabolites downregulated in response to the habanero pepper diet. Further investigation by integration analysis between transcriptome and metabolome data at gene pathway levels revealed six unique enriched pathways, including phenylalanine metabolism; insect hormone biosynthesis; pyrimidine metabolism; glyoxylate, and dicarboxylate metabolism; glycine, serine, threonine metabolism; and glycerolipid metabolism. In view of the transcriptome and metabolome findings, our comprehensive analysis of the response to a pepper diet in Drosophila have implications for exploring the molecular mechanism of pepper consumption.

Application of Nanomicelles in Enhancing Bioavailability and Biological Efficacy of Bioactive Nutrients

Nutraceuticals provide many biological benefits besides their basic nutritional value. However, their biological efficacies are often limited by poor absorption and low bioavailability. Nanomaterials have received much attention as potential delivery systems of nutrients and phytonutrients for multiple applications. Nanomicelles are nanosized colloidal structures with a hydrophobic core and hydrophilic shell. Due to their unique characteristics, they have shown great perspectives in food and nutraceutical science. In this review, we discussed the unique properties of nanomicelles. We also emphasized the latest advances on the design of different nanomicelles for efficient delivery and improved bioavailability of various nutrients. The role of nanomicelles in the efficacy improvement of bioactive components from nutraceutical and health foods has been included. Importantly, the safety concerns on nano-processed food products were highlighted.

Capsaicin for Weight Control: “Exercise in a Pill” (or Just Another Fad)?

Medical management of obesity represents a large unmet clinical need. Animal experiments suggest a therapeutic potential for dietary capsaicin, the pungent ingredient in hot chili peppers, to lose weight. This is an attractive theory since capsaicin has been a culinary staple for thousands of years and is generally deemed safe when consumed in hedonically acceptable, restaurant-like doses. This review critically evaluates the available experimental and clinical evidence for and against capsaicin as a weight control agent and comes to the conclusion that capsaicin is not a magic “exercise in a pill”, although there is emerging evidence that it may help restore a healthy gut microbiota.

Personalized Nutrition in the Management of Female Infertility: New Insights on Chronic Low-Grade Inflammation

Increasing evidence on the significance of nutrition in reproduction is emerging from both animal and human studies, suggesting a mutual association between nutrition and female fertility. Different “fertile” dietary patterns have been studied; however, in humans, conflicting results or weak correlations are often reported, probably because of the individual variations in genome, proteome, metabolome, and microbiome and the extent of exposure to different environmental conditions. In this scenario, “precision nutrition”, namely personalized dietary patterns based on deep phenotyping and on metabolomics, microbiome, and nutrigenetics of each case, might be more efficient for infertile patients than applying a generic nutritional approach. In this review, we report on new insights into the nutritional management of infertile patients, discussing the main nutrigenetic, nutrigenomic, and microbiomic aspects that should be investigated to achieve effective personalized nutritional interventions. Specifically, we will focus on the management of low-grade chronic inflammation, which is associated with several infertility-related diseases.

Capsaicin directly promotes adipocyte browning in the chemical compound-induced brown adipocytes converted from human dermal fibroblasts

Human brown fat is a potential therapeutic target for preventing obesity and related metabolic diseases by dissipating energy as heat through uncoupling protein 1 (UCP1). We have previously reported a method to obtain chemical compound-induced brown adipocytes (ciBAs) converted from human dermal fibroblasts under serum-free conditions. However, pharmacological responses to bioactive molecules have been poorly characterised in ciBAs. This study showed that the treatment with Capsaicin, an agonist of transient receptor potential vanilloid 1, directly activated adipocyte browning such as UCP1 expression, mitochondrial biogenesis, energy consumption rates, and glycerol recycling in ciBAs. Furthermore, genome-wide transcriptome analysis indicated that Capsaicin activated a broad range of metabolic genes including glycerol kinase and glycerol 3-phosphate dehydrogenase 1, which could be associated with the activation of glycerol recycling and triglyceride synthesis. Capsaicin also activated UCP1 expression in immortalised human brown adipocytes but inhibited its expression in mesenchymal stem cell-derived adipocytes. Altogether, ciBAs successfully reflected the direct effects of Capsaicin on adipocyte browning. These findings suggested that ciBAs could serve as a promising cell model for screening of small molecules and dietary bioactive compounds targeting human brown adipocytes.

Biogenic Phytochemicals Modulating Obesity: From Molecular Mechanism to Preventive and Therapeutic Approaches

The incidence of obesity and over bodyweight is emerging as a major health concern. Obesity is a complex metabolic disease with multiple pathophysiological clinical conditions as comorbidities are associated with obesity such as diabetes, hypertension, cardiovascular disorders, sleep apnea, osteoarthritis, some cancers, and inflammation-based clinical conditions. In obese individuals, adipocyte cells increased the expression of leptin, angiotensin, adipocytokines, plasminogen activators, and C-reactive protein. Currently, options for treatment and lifestyle behaviors interventions are limited, and keeping a healthy lifestyle is challenging. Various types of phytochemicals have been investigated for antiobesity potential. Here, we discuss pathophysiology and signaling pathways in obesity, epigenetic regulations, regulatory mechanism, functional ingredients in natural antiobesity products, and therapeutic application of phytochemicals in obesity.

Analysis of the Ability of Capsaicin to Modulate the Human Gut Microbiota In Vitro

Previous studies on capsaicin, the bioactive compound in chili peppers, have shown that it may have a beneficial effect in vivo when part of a regular diet. These positive health benefits, including an anti-inflammatory potential and protective effects against obesity, are often attributed to the gut microbial community response to capsaicin. However, there is no consensus on the mechanism behind the protective effect of capsaicin. In this study, we used an in vitro model of the human gut microbiota to determine how regular consumption of capsaicin impacts the gut microbiota. Using a combination of NextGen sequencing and metabolomics, we found that regular capsaicin treatment changed the structure of the gut microbial community by increasing diversity and certain SCFA abundances, particularly butanoic acid. Through this study, we determined that the addition of capsaicin to the in vitro cultures of the human gut microbiome resulted in increased diversity of the microbial community and an increase in butanoic acid. These changes may be responsible for the health benefits associated with CAP consumption.

Obesity history, physical exam, laboratory, body composition, and energy expenditure: An Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) 2022

Background

This Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) on History, Physical Exam, Body Composition and Energy Expenditure is intended to provide clinicians an overview of the clinical and diagnostic evaluation of patients with pre-obesity/obesity.

Methods

The scientific information for this CPS is based upon published scientific citations, clinical perspectives of OMA authors, and peer review by the Obesity Medicine Association leadership.

Results

This CPS outlines important components of medical, dietary, and physical activity history as well as physical exams, with a focus on specific aspects unique to managing patients with pre-obesity or obesity. Patients with pre-obesity/obesity benefit from the same preventive care and general laboratory testing as those without an increase in body fat. In addition, patients with pre-obesity/obesity may benefit from adiposity-specific diagnostic testing - both generally and individually - according to patient presentation and clinical judgment. Body composition testing, such as dual energy x-ray absorptiometry, bioelectrical impedance, and other measures, each have their own advantages and disadvantages. Some patients in clinical research, and perhaps even clinical practice, may benefit from an assessment of energy expenditure. This can be achieved by several methods including direct calorimetry, indirect calorimetry, doubly labeled water, or estimated by equations. Finally, a unifying theme regarding the etiology of pre-obesity/obesity and effectiveness of treatments of obesity centers on the role of biologic and behavior efficiencies and inefficiencies, with efficiencies more often associated with increases in fat mass and inefficiencies more often associated with decreases in fat mass.

Conclusion

The Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) on History, Physical Exam, Body Composition and Energy Expenditure is one of a series of OMA CPSs designed to assist clinicians in the care of patients with the disease of pre-obesity/obesity.

Anti-Obesity Potential of Ponciri Fructus: Effects of Extracts, Fractions and Compounds on Adipogenesis in 3T3-L1 Preadipocytes

BACKGROUND

Ponciri Fructus, a crude drug consisting of the dried immature fruits of Poncirus trifoliata (L.) Raf., is a popular folk medicine used for the treatment of allergy and gastrointestinal disorders in Korea and China. In this study, the anti-adipogenic activity of extracts and isolated compounds were evaluated using 3T3-L1 preadipocytes.

METHODS

Dried immature fruits were extracted and fractionated into n-hexane, ethyl acetate (EtOAc), n-butanol and water-soluble fractions. The ethanol extract and fractions were tested for anti-adipogenic activity in the 3T3-L1 cell line. The active fractions (n-hexane and EtOAc fractions) were further subjected to chromatographic techniques to isolate and identify active compounds. Furthermore, the isolated compounds were evaluated for their anti-adipogenic activity.

RESULTS

Altogether, seven compounds, including two flavonoids, one phytosteroid and four coumarin derivatives, were isolated. Ethanol extract, n-hexane fraction, EtOAc fraction and three isolated compounds (phellopterin, oxypeucedanin and poncirin) showed significant anti-adipogenic activity as observed by reduced lipid deposition in differentiated 3T3-L1 cells. Further, oxypeucedanin downregulated the key adipogenic markers, such as peroxisome proliferator-activated receptors proteins γ (PPAR-γ), sterol response element binding proteins-1 (SREBP-1), CCAAT/enhancer binding proteins-α (C/EBP-α), adipocyte-specific lipid binding proteins (FABP-4), adipocyte fatty acid binding proteins (aP2), lipoprotein lipase (LPL) and leptin.

CONCLUSION

This study indicated that the ethanol extract, hexane fraction and ethyl acetate fraction of P. trifoliata fruits possess strong anti-adipogenic activity, containing the active compounds such as phellopterin, oxypeucedanin and poncirin. Further research is recommended to explore their efficacy and safety in animal and clinical models.

Distribution of transient receptor potential vanilloid-1 channels in gastrointestinal tract of patients with morbid obesity

BACKGROUND

Transient receptor potential vanilloid-1 (TRPV1), a nonselective cation channel, is activated by capsaicin, a pungent ingredient of hot pepper. Previous studies have suggested a link between obesity and capsaicin-associated pathways, and activation of TRPV1 may provide an alternative approach for obesity treatment. However, data on the TRPV1 distribution in human gastric mucosa are limited, and the degree of TRPV1 distribution in the gastric and duodenal mucosal cells of obese people in comparison with normal-weight individuals is unknown.

AIM

To clarify gastric and duodenal mucosal expression of TRPV1 in humans and compare TRPV1 expression in obese and healthy individuals.

METHODS

Forty-six patients with a body mass index (BMI) of > 40 kg/m² and 20 patients with a BMI between 18-25 kg/m² were included. Simultaneous biopsies from the fundus, antrum, and duodenum tissues were obtained from subjects between the ages of 18 and 65 who underwent esophagogastroduodenoscopy. Age, sex, history of alcohol and cigarette consumption, and past medical history regarding chronic diseases and medications were accessed from patient charts and were analyzed accordingly. Evaluation with anti-TRPV1 antibody was performed separately according to cell types in the fundus, antrum, and duodenum tissues using an immunoreactivity score. Data were analyzed using SPSS 17.0.

RESULTS

TRPV1 expression was higher in the stomach than in the duodenum and was predominantly found in parietal and chief cells of the fundus and mucous and foveolar cells of the antrum. Unlike foveolar cells in the antrum, TRPV1 was relatively low in foveolar cells in the fundus (4.92 ± 0.49 vs 0.48 ± 0.16, P < 0.01, Mann-Whitney U test). Additionally, the mucous cells in the duodenum also had low levels of TRPV1 compared to mucous cells in the antrum (1.33 ± 0.31 vs 2.95 ± 0.46, P < 0.01, Mann-Whitney U test). TRPV1 expression levels of different cell types in the fundus, antrum, and duodenum tissues of the morbidly obese group were similar to those of the control group. Staining with TRPV1 in fundus chief cells and antrum and duodenum mucous cells was higher in patients aged ≥ 45 years than in patients < 45 years (3.03 ± 0.42, 4.37 ± 0.76, 2.28 ± 0.55 vs 1.9 ± 0.46, 1.58 ± 0.44, 0.37 ± 0.18, P = 0.03, P < 0.01, P < 0.01, respectively, Mann-Whitney U test). The mean staining levels of TRPV1 in duodenal mucous cells in patients with diabetes and hypertension were higher than those in patients without diabetes and hypertension (diabetes: 2.11 ± 0.67 vs 1.02 ± 0.34, P = 0.04; hypertension: 2.42 ± 0.75 vs 1.02 ± 0.33, P < 0.01 Mann-Whitney U test).

CONCLUSION

The expression of TRPV1 is unchanged in the gastroduodenal mucosa of morbidly obese patients demonstrating that drugs targeting TRPV1 may be effective in these patients.

Hot red pepper powder as a safe alternative to antibiotics in organic poultry feed: An updated overview

Globally, several studies have investigated the utilization and efficacy of promising medicinal herbal plants to enhance livestock and poultry production. The most commonly investigated phytobiotics in broiler ration were oregano, garlic, thyme, rosemary, black pepper, hot red pepper (HRP), and sage. Phytobiotics are classified on the basis of the medicinal properties of plants, their essential oil extracts, and their bioactive compounds. The majority of bioactive compounds in plants are secondary metabolites, such as terpenoids, phenolic, glycosides, and alkaloids. The composition and concentrations of these bioactive constitutes vary according to their biological factors and manufacturing and storage conditions. Furthermore, HRP is one of the most important and widely used spices in the human diet. Capsicum annum, that is, HRP, is a species of the plant genus Capsicum (pepper), which is a species native to southern North America and northern South America and is widely grown and utilized for its fresh or cooked fruits. Moreover, these fruits may be used as dried powders or processed forms of oleoresins. Researches have proven that C. annuum is the only plant that produces the alkaloid capsaicinoids. Approximately 48% of its active substances are capsaicin (8-methyl-N-vanillyl-6-nonemide), the main active compound responsible for the intense effects of HRP varieties and the main component inducing the hot flavor. This review aimed to highlight the effects of HRP as a phytobiotic in broiler nutrition and its mode of action as a possible alternative to antibiotics and clarify its impact on broiler and layer productivity.

Signaling Targets Related to Antiobesity Effects of Capsaicin: A Scoping Review

The search for new antiobesogenic agents is increasing because of the current obesity pandemic. Capsaicin (Caps), an exogenous agonist of the vanilloid receptor of transient potential type 1 (TRPV1), has shown promising results in the treatment of obesity. This scoping review aims to verify the pathways mediating the effects of Caps in obesity and the different methods adopted to identify these pathways. The search was carried out using data from the EMBASE, MEDLINE (PubMed), Web of Science, and SCOPUS databases. Studies considered eligible evaluated the mechanisms of action of Caps in obesity models or cell types involved in obesity. Nine studies were included and 100% (n = 6) of the in vivo studies showed a high risk of bias. Of the 9 studies, 66.6% (n = 6) administered Caps orally in the diet and 55.5% (n = 5) used a concentration of Caps of 0.01% in the diet. In vitro, the most tested concentration was 1 μM (88.9%; n = 8). Capsazepine was the antagonist chosen by 66.6% (n = 6) of the studies. Seven studies (77.8%) linked the antiobesogenic effects of Caps to TRPV1 activation and 3 (33.3%) indicated peroxisome proliferator-activated receptor (PPAR) involvement as an upstream connection to TRPV1, rather than a direct metabolic target of Caps. The main secondary effects of Caps were lower weight gain (33.3%; n = 3) or loss (22.2%; n = 2), greater improvement in lipid profile (33.3%; n = 3), lower white adipocyte adipogenesis (33.3%; n = 3), browning process activation (44.4%; n = 4), and higher brown adipocyte activity (33.3%; n = 3) compared with those of the control treatment. Some studies have shown that PPAR agonists modulate TRPV1 activity, and no study has evaluated the simultaneous antagonism of these 2 receptors. Consequently, further studies are necessary to elucidate the role of each of these signaling molecules in the antiobesogenic effects of Caps.

Effect of supplementing lactation and nursery pig diets with capsaicin on growth performance and gene expression of nursery pigs

The objective of this study was to determine the effects of supplementing capsaicin in diets for lactating sows and their offspring on the growth performance and gene expression of pigs postweaning. Twenty-eight multiparous sows were fed corn-soybean meal-based diets without (n = 14) and with (n = 14) capsaicin (2.5 mg/kg) during a 19-d lactation period. Litters from these sows (n = 288 pigs) were weaned and assigned to 36 blocks (pens) based on maternal dietary treatment and initial body weight (BW) to provide 8 pigs/pen. Blocks were assigned randomly to one of two nursery dietary treatments (control or capsaicin supplemented diets) in a 2 × 2 factorial arrangement of treatments to provide nine replications per treatment combination. A three-phase nursery feeding program was used and consisted of feeding phase 1 (weaning to d 7), phase 2 (d 8–21), and phase 3 (d 22–38) diets postweaning, without and with 1.0, 1.3, and 1.6 mg capsaicin/kg of diet, respectively. Data were analyzed using a mixed model with the effect of nursery dietary treatment nested within sow lactation treatment, the effect of time with repeated measures, and interactions between treatments and wk postweaning. On d 38 postweaning, blood samples were collected from one pig in each pen (n = 36) with BW closest to the pen average for RNA sequencing and gene expression analysis. There were no effects of feeding capsaicin diets to lactating sows and/or their weaned offspring on BW, average daily gain, or average daily feed intake of pigs during the 35-d nursery period. However, pigs weaned from sows fed capsaicin during lactation and continuing to be fed capsaicin diets during the nursery period tended (P = 0.09) to have greater gain:feed (G:F) than pigs fed the other dietary treatments. Furthermore, there was an interaction (P < 0.01) for G:F for dietary treatment and week postweaning, where the magnitude of improvement was greater during the first week postweaning than subsequent wks. There were a limited number of differentially expressed genes among dietary treatment combinations but the greatest number occurred in offspring from sows that were fed capsaicin during lactation. In conclusion, the combination of feeding capsaicin to sows during lactation and to their offspring after weaning appears to improve gain efficiency for the first wk postweaning and may alter gene expression to a greater extent than when capsaicin is supplemented only in the nursery diets.

Food phenolics stimulate adipocyte browning via regulating gut microecology

Fat browning has piqued the interest of researchers as a potential target for treating obesity and related metabolic disorders. Recruitment of brown adipocytes leads to enhanced energy dissipation and reduced adiposity, thus facilitating the maintenance of metabolic homeostasis. Evidence is increasing to support the crucial roles of polyphenols and gut microecology in turning fat "brown". However, it is not clear whether the intestinal microecology is involved in polyphenol-mediated regulation of adipose browning, so this concept is worthy of exploration. In this review, we summarize the current knowledge, mostly from studies with murine models, supporting the concept that the effects of food phenolics on brown fat activation and white fat browning can be attributed to their regulatory actions on gut microecology, including microbial community profile, gut metabolites, and gut-derived hormones. Furthermore, the potential underlying pathways involved are also discussed. Basically, understanding gut microecology paves the way to determine the underlying roles and mechanisms of food phenolics in adipose browning.

Exploiting the Anti-Inflammatory Potential of White Capsicum Extract by the Nanoformulation in Phospholipid Vesicles

The peppers of the Capsicum species are exploited in many fields, as flavoring agents in food industry, or as decorative and therapeutic plants. Peppers show a diversified phytochemical content responsible for different biological activities. Synergic activity exerted by high levels of antioxidant compounds is responsible for their important anti-inflammatory property. A methanolic extract was obtained from a new pepper genotype and tested for anti-inflammatory activity. The extract was incorporated into phospholipid vesicles to increase the bioavailability of its bioactive components. Two types of phospholipid vesicles were produced, conventional liposomes and Penetration Enhancer containing Vesicles (PEVs). They were tested in human monoblastic leukemia U937 cell line, showing no cytotoxic effect. The intracellular reactive oxygen species (ROS) and nitric oxide (NO) levels were measured to value the in vitro efficacy of the vesicles in regulating inflammatory responses. Liposomal incorporation significantly reduced ROS levels in extract-treated LPS-activated cells. Furthermore, LC-MS/MS analyses demonstrated that liposomes facilitated the transport of the extract components across the cell membrane and their accumulation into the cytoplasm.

Oral Capsaicinoid Administration Alters the Plasma Endocannabinoidome and Fecal Microbiota of Reproductive-Aged Women Living with Overweight and Obesity

Capsaicinoids, the pungent principles of chili peppers and prototypical activators of the transient receptor potential of the vanilloid type-1 (TRPV1) channel, which is a member of the expanded endocannabinoid system known as the endocannabinoidome (eCBome), counteract food intake and obesity. In this exploratory study, we examined the blood and stools from a subset of the participants in a cohort of reproductive-aged women with overweight/obesity who underwent a 12-week caloric restriction of 500 kcal/day with the administration of capsaicinoids (two capsules containing 100 mg of a capsicum annuum extract (CAE) each for a daily dose of 4 mg of capsaicinoids) or a placebo. Samples were collected immediately before and after the intervention, and plasma eCBome mediator levels (from 23 participants in total, 13 placebo and 10 CAE) and fecal microbiota taxa (from 15 participants in total, 9 placebo and 6 CAE) were profiled using LC-MS/MS and 16S metagenomic sequencing, respectively. CAE prevented the reduced caloric-intake-induced decrease in beneficial eCBome mediators, i.e., the TRPV1, GPR119 and/or PPARα agonists, N-oleoyl-ethanolamine, N-linoleoyl-ethanolamine and 2-oleoyl-glycerol, as well as the anti-inflammatory N-acyl-ethanolamines N-docosapentaenyl-ethanolamine and N-docosahexaenoyl-ethanolamine. CAE produced few but important alterations in the fecal microbiota, such as an increased relative abundance of the genus Flavonifractor, which is known to be inversely associated with obesity. Correlations between eCBome mediators and other potentially beneficial taxa were also observed, thus reinforcing the hypothesis of the existence of a link between the eCBome and the gut microbiome in obesity.

Enzymes, In Vivo Biocatalysis, and Metabolic Engineering for Enabling a Circular Economy and Sustainability

Since the industrial revolution, the rapid growth and development of global industries have depended largely upon the utilization of coal-derived chemicals, and more recently, the utilization of petroleum-based chemicals. These developments have followed a linear economy model (produce, consume, and dispose). As the world is facing a serious threat from the climate change crisis, a more sustainable solution for manufacturing, i.e., circular economy in which waste from the same or different industries can be used as feedstocks or resources for production offers an attractive industrial/business model. In nature, biological systems, i.e., microorganisms routinely use their enzymes and metabolic pathways to convert organic and inorganic wastes to synthesize biochemicals and energy required for their growth. Therefore, an understanding of how selected enzymes convert biobased feedstocks into special (bio)chemicals serves as an important basis from which to build on for applications in biocatalysis, metabolic engineering, and synthetic biology to enable biobased processes that are greener and cleaner for the environment. This review article highlights the current state of knowledge regarding the enzymatic reactions used in converting biobased wastes (lignocellulosic biomass, sugar, phenolic acid, triglyceride, fatty acid, and glycerol) and greenhouse gases (CO₂ and CH₄) into value-added products and discusses the current progress made in their metabolic engineering. The commercial aspects and life cycle assessment of products from enzymatic and metabolic engineering are also discussed. Continued development in the field of metabolic engineering would offer diversified solutions which are sustainable and renewable for manufacturing valuable chemicals.

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.

Diversity in Chemical Structures and Biological Properties of Plant Alkaloids

Phytochemicals belonging to the group of alkaloids are signature specialized metabolites endowed with countless biological activities. Plants are armored with these naturally produced nitrogenous compounds to combat numerous challenging environmental stress conditions. Traditional and modern healthcare systems have harnessed the potential of these organic compounds for the treatment of many ailments. Various chemical entities (functional groups) attached to the central moiety are responsible for their diverse range of biological properties. The development of the characterization of these plant metabolites and the enzymes involved in their biosynthesis is of an utmost priority to deliver enhanced advantages in terms of biological properties and productivity. Further, the incorporation of whole/partial metabolic pathways in the heterologous system and/or the overexpression of biosynthetic steps in homologous systems have both become alternative and lucrative methods over chemical synthesis in recent times. Moreover, in-depth research on alkaloid biosynthetic pathways has revealed numerous chemical modifications that occur during alkaloidal conversions. These chemical reactions involve glycosylation, acylation, reduction, oxidation, and methylation steps, and they are usually responsible for conferring the biological activities possessed by alkaloids. In this review, we aim to discuss the alkaloidal group of plant specialized metabolites and their brief classification covering major categories. We also emphasize the diversity in the basic structures of plant alkaloids arising through enzymatically catalyzed structural modifications in certain plant species, as well as their emerging diverse biological activities. The role of alkaloids in plant defense and their mechanisms of action are also briefly discussed. Moreover, the commercial utilization of plant alkaloids in the marketplace displaying various applications has been enumerated.

Accumulating evidence to support the safe and efficacious use of a proprietary blend of capsaicinoids in mediating risk factors for obesity

Obesity is a significant public health concern, and finding safe and effective means for combating this condition is needed. This study investigates the safety and efficacy of supplementation of a blend of capsaicinoids on weight gain, fat mass, and blood chemistry in a high-fat diet (HFD) model of obesity in mice and on adipocyte differentiation and gene expression in 3T3-L1 preadipocytes. High-fat diet (HFD)-fed mice were treated with a proprietary capsaicinoid concentrate (Capsimax®; OmniActive Health Technologies Ltd., India) and compared to orlistat (ORL) and normal chow-fed mice (NC). Mice fed a high-fat diet showed significantly lower weight gain upon Capsimax® (CAP) administration than their HFD counterparts and similar to that observed with ORL animals. In addition, CAP decreased the high-fat diet-induced increases in adipose tissue and epididymal fat pad mass and hypertrophy after 52 days of treatment. Both the CAP and ORL groups had increased plasma concentrations of leptin. CAP extracts decreased triacylglycerol content in 3T3-L1 preadipocytes and decreased markers of adipogenesis including peroxisome proliferator-activated receptor (PPAR-ɣ) and fatty acid-binding protein 4 (FABP4). Expression of genes involved in lipogenesis such as stearoyl-CoA desaturase (SCD) and fatty acid synthase (FSN) was decreased by CAP in a dose-dependent manner. Thermogenic genes and markers of brown adipose tissue including uncoupling protein 1 (UCP1) and PR domain-containing 16 (Prdm16) were induced by CAP in the preadipocyte cells. These in vivo and in vitro data support that this proprietary capsaicinoid concentrate reduces weight gain and adiposity at least in part through decreasing lipogenesis and increasing thermogenesis.