Kaempferia parviflora extract increases whole-body energy expenditure in humans: roles of brown adipose tissue

Kaempferia parviflora extract and its component polymethoxyflavones suppress adipogenic differentiation of human bone marrow-derived mesenchymal stem cells via the AMPK pathway

BACKGROUND

Kaempferia parviflora Wall. ex. Baker (KP) has been reported to exhibit anti-obesity effects. However, the detailed mechanism of the anti-obesity effect of KP extract (KPE) is yet to be clarified. Here, we investigated the effect of KPE and its component polymethoxyflavones (PMFs) on the adipogenic differentiation of human mesenchymal stem cells (MSCs).

METHODS AND RESULTS

KPE and PMFs fraction (2.5 µg/mL) significantly inhibited lipid and triacylglyceride accumulation in MSCs; lipid accumulation in MSCs was suppressed during the early stages of differentiation (days 0-3) but not during the mid (days 3-7) or late (days 7-14) stages. Treatment with KPE and PMFs fractions significantly suppressed peroxisome proliferator-activated receptor-γ (PPARγ), CCAAT/enhancer binding protein α (C/EBPα), and various adipogenic metabolic factors. Treatment with KPE and PMFs fraction induced the activation of AMP-activated protein kinase (AMPK) signaling, and pretreatment with an AMPK signaling inhibitor significantly attenuated KPE- and PMFs fraction-induced suppression of lipid formation.

CONCLUSIONS

Our findings demonstrate that KPE and PMFs fraction inhibit lipid formation by inhibiting the differentiation of undifferentiated MSCs into adipocyte lineages via AMPK signaling, and this may be the mechanism underlying the anti-obesity effects of KPE and PMFs. Our study lays the foundation for the elucidation of the anti-obesity mechanism of KPE and PMFs.

Kaempferia parviflora rhizome extract exerts anti-obesity effect in high-fat diet-induced obese C57BL/6N mice

Kaempferia parviflora (KP) rhizome, also called black ginger, has been used as a herbal medicine for many centuries. This current study was aimed at exploring whether KP rhizome extract (KPE) had anti-obesity effects and the mechanism involved. Five-week-old C57BL/6N male mice were allocated into five groups for 8-week feeding with control diet (CD), high-fat diet (HFD), HFD + 150 mg/kg body weight (BW)/day KPE (HFD+K150), HFD + 300 mg/kg BW/day KPE (HFD+K300), and HFD + 600 mg/kg BW/day KPE (HFD+K600). KPE decreased BW, body fat mass, adipose tissue weight, adipocyte size, and serum levels of glucose, triglycerides, cholesterol, insulin, and leptin in HFD-induced obese C57BL/6N mice. KPE inhibited adipogenesis by decreasing CCAAT/enhancer binding protein α, peroxisome proliferator-activated receptor γ, sterol regulatory element-binding protein-1c, acetyl-CoA carboxylase 1, ATP-citrate lyase, and fatty acid synthase mRNA expression. KPE improved lipolysis by increasing carnitine palmitoyl transferase 1 and hormone-sensitive lipase mRNA expression. These results suggest that KPE may have inhibited HFD-induced obesity by regulating several pathways involved in decreasing adipogenesis and enhancing lipolysis. Thus, the results suggest that KPE (or KP) may be applicable as an anti-obesity agent.

Browning of Adipocytes: A Potential Therapeutic Approach to Obesity

The increasing prevalence of overweight and obesity suggests that current strategies based on diet, exercise, and pharmacological knowledge are not sufficient to tackle this epidemic. Obesity results from a high caloric intake and energy storage, the latter by white adipose tissue (WAT), and when neither are counterbalanced by an equally high energy expenditure. As a matter of fact, current research is focused on developing new strategies to increase energy expenditure. Against this background, brown adipose tissue (BAT), whose importance has recently been re-evaluated via the use of modern positron emission techniques (PET), is receiving a great deal of attention from research institutions worldwide, as its main function is to dissipate energy in the form of heat via a process called thermogenesis. A substantial reduction in BAT occurs during normal growth in humans and hence it is not easily exploitable. In recent years, scientific research has made great strides and investigated strategies that focus on expanding BAT and activating the existing BAT. The present review summarizes current knowledge about the various molecules that can be used to promote white-to-brown adipose tissue conversion and energy expenditure in order to assess the potential role of thermogenic nutraceuticals. This includes tools that could represent, in the future, a valid weapon against the obesity epidemic.

The industrially important genus Kaempferia: An ethnopharmacological review

Kaempferia, a genus of the family Zingiberaceae, is widely distributed with more than 50 species which are mostly found throughout Southeast Asia. These plants have important ethnobotanical significance as many species are used in Ayurvedic and other traditional medicine preparations. This genus has received a lot of scholarly attention recently as a result of the numerous health advantages it possesses. In this review, we have compiled the scientific information regarding the relevance, distribution, industrial applications, phytochemistry, ethnopharmacology, tissue culture and conservation initiative of the Kaempferia genus along with the commercial realities and limitations of the research as well as missing industrial linkages followed by an exploration of some of the likely future promising clinical potential. The current review provides a richer and deeper understanding of Kaempferia, which can be applied in areas like phytopharmacology, molecular research, and industrial biology. The knowledge from this study can be further implemented for the establishment of new conservation strategies.

Nutraceuticals in Brown Adipose Tissue Activation

Obesity and its associated comorbidities have become pandemic, and challenge the global healthcare system. Lifestyle changes, nutritional interventions and phamaceuticals should be differently combined in a personalized strategy to tackle such a public health burden. Altered brown adipose tissue (BAT) function contributes to the pathophysiology of obesity and glucose metabolism dysfunctions. BAT thermogenic activity burns glucose and fatty acids to produce heat through uncoupled respiration, and can dissipate the excessive calorie intake, reduce glycemia and circulate fatty acids released from white adipose tissue. Thus, BAT activity is expected to contribute to whole body energy homeostasis and protect against obesity, diabetes and alterations in lipid profile. To date, pharmacological therapies aimed at activating brown fat have failed in clinical trials, due to cardiovascular side effects or scarce efficacy. On the other hand, several studies have identified plant-derived chemical compounds capable of stimulating BAT thermogenesis in animal models, suggesting the translational applications of dietary supplements to fight adipose tissue dysfunctions. This review describes several nutraceuticals with thermogenic properties and provides indications, at a molecular level, of the regulation of the adipocyte thermogenesis by the mentioned phytochemicals.

PET/MRI-evaluated brown adipose tissue activity may be related to dietary MUFA and omega-6 fatty acids intake

An investigation of new ways to activate brown adipose tissue (BAT) is highly valuable, as it is a possible tool for obesity prevention and treatment. The aim of our study was to evaluate the relationships between dietary intake and BAT activity. The study group comprised 28 healthy non-smoking males aged 21–42 years. All volunteers underwent a physical examination and 75-g OGTT and completed 3-day food intake diaries to evaluate macronutrients and fatty acid intake. Body composition measurements were assessed using DXA scanning. An FDG-18 PET/MR was performed to visualize BAT activity. Brown adipose tissue was detected in 18 subjects (67% normal-weight individuals and 33% overweight/obese). The presence of BAT corresponded with a lower visceral adipose tissue (VAT) content (p = 0.04, after adjustment for age, daily kcal intake, and DXA Lean mass). We noted significantly lower omega-6 fatty acids (p = 0.03) and MUFA (p = 0.02) intake in subjects with detected BAT activity after adjustment for age, daily average kcal intake, and DXA Lean mass, whereas omega-3 fatty acids intake was comparable between the two groups. BAT presence was positively associated with the concentration of serum IL-6 (p = 0.01) during cold exposure. Our results show that BAT activity may be related to daily omega-6 fatty acids intake.

A Comprehensive Review on Anti-obesity Potential of Medicinal Plants and their Bioactive Compounds

Background:

Obesity is a complex health and global epidemic issue. It is an increasing global health challenge covering significant social and economic costs. Abnormal accumulation of fat in the body may increase the health risks including diabetes, hypertension, osteoarthritis, sleep apnea, cardiovascular diseases, stroke and cancer. Synthetic drugs available on the market reported to have several side effects. Therefore, the management of obesity got to involve the traditional use of medicinal plants which helps to search the new therapeutic targets and supports the research and development of anti-obesity drugs.

Objective:

This review aim to update the data and provide a comprehensive report of currently available knowledge of medicinal plants and phyto-chemical constituents reported for their anti-obesity activity.

Methodology:

An electronic search of the periodical databases like Web of Science, Scopus, PubMed, Scielo, Niscair, ScienceDirect, Springerlink, Wiley, SciFinder and Google Scholar with information reported the period 1991-2019, was used to retrieve published data.

Results:

A comprehensive report of the present review manuscript is an attempt to list the medicinal plants with anti-obesity activity. The review focused on plant extracts, isolated chemical compounds with their mechanism of action and their preclinical experimental model, clinical studies for further scientific research.

Conclusion:

This review is the compilation of the medicinal plants and their constituents reported for the managements of obesity. The data will fascinate the researcher to initiate further research that may lead to the drug for the management of obesity and their associated secondary complications. Several herbal plants and their respective lead constituents were also screened by preclinical In-vitro and In-vivo, clinical trials and are effective in the treatment of obesity. Therefore, there is a need to develop and screen large number of plant extracts and this approach can surely be a driving force for the discovery of anti-obesity drugs from medicinal plants.

An update on brown adipose tissue and obesity intervention: Function, regulation and therapeutic implications

Overweight and obesity have become a world-wide problem. However, effective intervention approaches are limited. Brown adipose tissue, which helps maintain body temperature and contributes to thermogenesis, is dependent on uncoupling protein1. Over the last decade, an in-creasing number of studies have found that activating brown adipose tissue and browning of white adipose tissue can protect against obesity and obesity-related metabolic disease. Brown adipose tissue has gradually become an appealing therapeutic target for the prevention and re-versal of obesity. However, some important issues remain unresolved. It is not certain whether increasing brown adipose tissue activity is the cause or effect of body weight loss or what the risks might be for sympathetic nervous system-dependent non-shivering thermogenesis. In this review, we comprehensively summarize approaches to activating brown adipose tissue and/or browning white adipose tissue, such as cold exposure, exercise, and small-molecule treatment. We highlight the functional mechanisms of small-molecule treatment and brown adipose tissue transplantation using batokine, sympathetic nervous system and/or gut microbiome. Finally, we discuss the causality between body weight loss induced by bariatric surgery, exercise, and brown adipose tissue activity.

TRPA1: Pharmacology, natural activators and role in obesity prevention

Transient receptor potential ankyrin 1 (TRPA1) channel is a calcium permeable, non-selective cation channel, expressed in the sensory neurons and non-neuronal cells of different tissues. Initially studied for its role in pain and inflammation, TRPA1 has now functionally involved in multiple other physiological functions. TRPA1 channel has been extensively studied for modulation by pungent compounds present in the spices and herbs. In the last decade, the role of TRPA1 agonism in body weight reduction, secretion of hunger and satiety hormones, insulin secretion and thermogenesis, has unveiled the potential of the TRPA1 channel to be used as a preventive target to tackle obesity and associated comorbidities including insulin resistance in type 2 diabetes. In this review, we summarized the recent findings of TRPA1 based dietary/non-dietary modulation for its role in obesity prevention and therapeutics.

Medicinal importance of Kaempferia galanga L. (Zingiberaceae): A comprehensive review

Kaempferia galanga included in the Zingiberaceae family is one of the potential medicinal plants with aromatic rhizome. In traditional medicine in Asian countries, this plant is widely used by local practitioners. This plant is widely cultivated in most Southeast Asian countries such as Cambodia, Vietnam, Malaysia, Thailand, and Indonesia. Ethyl-para-methoxycinnamate and ethyl-cinnamate are found as the main compounds in hexane, dichloromethane, and methanol extracts of K. galanga. This plant is traditionally used as an expectorant, stimulant, diuretic, carminative, and antipyretic remedy. In addition, K. galanga is used for treatment of diabetes, hypertension, cough, asthma, joint fractures, rheumatism, urticaria, vertigo, and intestinal injuries. Therefore, this study aimed to give a sneak peek view on galangal’s ethnobotany, toxicology, pharmacology, and phytochemistry.

Nutritional Regulation of Human Brown Adipose Tissue

The recent identification of brown adipose tissue in adult humans offers a new strategy to increase energy expenditure to treat obesity and associated metabolic disease. While white adipose tissue (WAT) is primarily for energy storage, brown adipose tissue (BAT) is a thermogenic organ that increases energy expenditure to generate heat. BAT is activated upon cold exposure and improves insulin sensitivity and lipid clearance, highlighting its beneficial role in metabolic health in humans. This review provides an overview of BAT physiology in conditions of overnutrition (obesity and associated metabolic disease), undernutrition and in conditions of altered fat distribution such as lipodystrophy. We review the impact of exercise, dietary macronutrients and bioactive compounds on BAT activity. Finally, we discuss the therapeutic potential of dietary manipulations or supplementation to increase energy expenditure and BAT thermogenesis. We conclude that chronic nutritional interventions may represent a useful nonpharmacological means to enhance BAT mass and activity to aid weight loss and/or improve metabolic health.

Polymethoxyflavone purified from Kaempferia parviflora reduces visceral fat in Japanese overweight individuals: a randomised, double-blind, placebo-controlled study

Visceral fat is a more important factor in obesity-associated disorders in Japanese individuals than in Caucasian individuals. The objective of this randomised, double-blind, placebo-controlled parallel group study, conducted in Japanese overweight adults, was to investigate the effects of polymethoxyflavone purified from Kaempferia parviflora on visceral fat. A total of 80 subjects (aged 20-64 years, 23.0 ≤ body mass index < 30 kg m-2) were randomly assigned in 1 : 1 ratio to either the active (polymethoxyflavone purified from K. parviflora) or placebo group. Over a 12-week period, each subject received two capsules containing polymethoxyflavone purified from K. parviflora (12 mg polymethoxyflavone per day) or placebo. The primary outcome was a reduction in visceral fat area (VFA), while the secondary outcome was a reduction in subcutaneous fat area (SFA) and total fat area (TFA). VFA was measured at 0, 8, and 12 weeks using computed tomography scanning. Results showed that VFA significantly reduced after 12 weeks in the active group and was significantly lower than in the placebo group at 8 and 12 weeks. A significant reduction was observed in SFA and TFA after 8 and 12 weeks in the active group; TFA was significantly lower than that in the placebo group at 8 and 12 weeks. No adverse events associated with the test supplements were observed in either group. Our study shows that administration of polymethoxyflavone purified from K. parviflora reduces visceral fat in Japanese overweight adults.

Supplementation of Kaempferia parviflora Extract Enhances Physical Fitness and Modulates Parameters of Heart Rate Variability in Adolescent Student-Athletes: A Randomized, Double-Blind, Placebo-Controlled Clinical Study

This randomized double-blind controlled study aimed to investigate the effects of a standardized Kaempferia parviflora (KP) extract on the physical fitness and heart rate variability (HRV) parameters in adolescent sport school students. 194 male students were recruited and randomized into two groups (n = 97), matched by age and sports. The KP-treated group received KP extract capsules at a dose of 360 mg/day and the control group received placebo capsules, continuously for 12 weeks. Physical fitness performance and HRV parameters were monitored with blood biochemical analysis for product safety. KP extract significantly increased the right-hand grip strength, the back-leg strength and maximal oxygen consumption (VO₂ max) and decreased the time used for 50-meter sprint test without changing the sit-and-reach test and the 40 yard technical test. For HRV parameters, KP extract significantly increased standard deviation of normal to normal intervals (SDNN), square root of the mean of square of successive normal to normal interval differences (RMSSD) and high frequency (HF) norm, without changing low frequency (LF) norm and LF/HF ratio. The increase in stress resistance and decrease in stress index were found in the KP-treated group, without changing the autonomic nervous system (ANS) activity and balance. Blood biochemical analysis showed normal values of all participants. This data indicates the safety and positive effects of KP on muscle strength, endurance and speed, but not on the flexibility and agility. The modulatory effects of KP extract on HRV parameters suggest its anti-stress effects and would encourage the application in a sport training and exercise.

Kaempferia parviflora Nanosuspension Formulation for Scalability and Improvement of Dissolution Profiles and Intestinal Absorption

Kaempferia parviflora (KP) is an herbal medicine for enhancement of physical fitness and male sexual function improvement with low oral absorption of the main active compounds, methoxyflavones. The purpose of this study is to optimize the preparation of nanosuspensions of KP extract for enhancing intestinal absorption using antisolvent precipitation technique which is an accessible nanomanufacturing methodology in the small industrial factory. Nanosuspensions were prepared using various types and concentrations of stabilizers. Then, the dry powder of KP nanosuspension was produced by spray drying. Its dissolution rate was determined using USP dissolution apparatus II. The rat everted intestinal sac was tested to confirm the improvement of intestinal absorption of KP nanosuspension. The result showed that 3% sodium lauryl sulfate (SLS) was the optimal condition for covering the nano-size of KP nanosuspension. KP nanosuspensions had particle sizes ranging from 100 to 300 nm with narrow size distribution (PDI < 0.60) and zeta potential at - 58 to - 70 mV. These characteristics were stable at 4°C and 25°C/60%RH for 1-month storage. Its methoxyflavones content also unchanged at 4°C and 25°C/60%RH for 1-month storage. KP nanosuspension released > 80% of the methoxyflavones within 30 min both in 0.1 N HCl and 0.01 M phosphate buffer solution (pH 6.8). Moreover, the developed nanosuspension dramatically improved the rat intestinal absorption about 10-fold. Therefore, the KP nanosuspension was successfully prepared. It has relatively high stability, fast dissolution rate, and high intestinal absorption.

Effect of the herbal medicines in obesity and metabolic syndrome: A systematic review and meta-analysis of clinical trials

Obesity is a medical situation in which excess body fat has gathered because of imbalance between energy intake and energy expenditure. In spite of the fact that the variety of studies are available for obesity treatment and management, its "globesity" still remains a big challenge all over the world. The current systematic review and meta-analysis aimed to evaluate the efficacy, safety, and mechanisms of effective herbal medicines in the management and treatment of obesity and metabolic syndrome in human. We systematically searched all relevant clinical trials via Web of Science, Scopus, PubMed, and the Cochrane database to assess the effects of raw or refined products derived from plants or parts of plants on obesity and metabolic syndrome in overweight and obesity adult subjects. All studies conducted by the end of May 2019 were considered in the systematic review. Data were extracted independently by two experts. The quality assessment was assessed using Consolidated Standards of Reporting Trials checklist. The main outcomes were anthropometric indices and metabolic syndrome components. Pooled effect of herbal medicines on obesity and metabolic syndrome were presented as standardized mean difference (SMD) and 95% confidence interval (CI). A total of 279 relevant clinical trials were included. Herbals containing green tea, Phaseolus vulgaris, Garcinia cambogia, Nigella sativa, puerh tea, Irvingia gabonensis, and Caralluma fimbriata and their active ingredients were found to be effective in the management of obesity and metabolic syndrome. In addition, C. fimbriata, flaxseed, spinach, and fenugreek were able to reduce appetite. Meta-analysis showed that intake of green tea resulted in a significant improvement in weight ([SMD]: -0.75 [-1.18, -0.319]), body mass index ([SMD]: -1.2 [-1.82, -0.57]), waist circumference ([SMD]: -1.71 [-2.66, -0.77]), hip circumference ([SMD]: -0.42 [-1.02, -0.19]), and total cholesterol, ([SMD]: -0.43 [-0.77, -0.09]). In addition, the intake of P. vulgaris and N. sativa resulted in a significant improvement in weight ([SMD]: -0.88, 95 % CI: [-1.13, -0.63]) and triglyceride ([SMD]: -1.67, 95 % CI: [-2.54, -0.79]), respectively. High quality trials are still needed to firmly establish the clinical efficacy of the plants in obesity and metabolic syndrome.

Recent Advances in Kaempferia Phytochemistry and Biological Activity: A Comprehensive Review

Background: Plants belonging to the genus Kaempferia (family: Zingiberaceae) are distributed in Asia, especially in the southeast region, and Thailand. They have been widely used in traditional medicines to cure metabolic disorders, inflammation, urinary tract infections, fevers, coughs, hypertension, erectile dysfunction, abdominal and gastrointestinal ailments, asthma, wounds, rheumatism, epilepsy, and skin diseases. Objective: Herein, we reported a comprehensive review, including the traditional applications, biological and pharmacological advances, and phytochemical constituents of Kaempheria species from 1972 up to early 2019. Materials and methods: All the information and reported studies concerning Kaempheria plants were summarized from library and digital databases (e.g., Google Scholar, Sci-finder, PubMed, Springer, Elsevier, MDPI, Web of Science, etc.). The correlation between the Kaempheria species was evaluated via principal component analysis (PCA) and agglomerative hierarchical clustering (AHC), based on the main chemical classes of compounds. Results: Approximately 141 chemical constituents have been isolated and reported from Kaempferia species, such as isopimarane, abietane, labdane and clerodane diterpenoids, flavonoids, phenolic acids, phenyl-heptanoids, curcuminoids, tetrahydropyrano-phenolic, and steroids. A probable biosynthesis pathway for the isopimaradiene skeleton is illustrated. In addition, 15 main documented components of volatile oils of Kaempheria were summarized. Biological activities including anticancer, anti-inflammatory, antimicrobial, anticholinesterase, antioxidant, anti-obesity-induced dermatopathy, wound healing, neuroprotective, anti-allergenic, and anti-nociceptive were demonstrated. Conclusions: Up to date, significant advances in phytochemical and pharmacological studies of different Kaempheria species have been witnessed. So, the traditional uses of these plants have been clarified via modern in vitro and in vivo biological studies. In addition, these traditional uses and reported biological results could be correlated via the chemical characterization of these plants. All these data will support the biologists in the elucidation of the biological mechanisms of these plants.

Evaluation of the Safety of Daily Consumption of Kaempferia parviflora Extract (KPFORCE): A Randomized Double-Blind Placebo-Controlled Trial

This study's aim was to evaluate the safety of daily consumption of Kaempferia parviflora extract (KPE) using a randomized double-blind placebo-controlled study with 52 recruited healthy Japanese subjects. Each subject received five KPE tablets (containing 150 mg of KPFORCE^™/tablet) or placebo daily for 4 weeks. There were no adverse events related to KPE intake or any abnormalities compared with placebo group in anthropometric, cardiovascular, blood, and urine parameters during the course of the study. Thus, daily KPE ingestion was found to be safe in healthy Japanese men and women.

In vivo effect of Kaempferia parviflora extract on pharmacokinetics of acetaminophen

Kaempferia parviflora is widely used as a food supplement and a herbal medicine for vitalization. Previous study has shown that K. parviflora had CYP2E1 inducer activity. It is likely to affect the metabolism of CYP2E1 substrates such as acetaminophen which is a common household pain relief medicine. This study investigated the possible pharmacokinetic interaction between K. parviflora and acetaminophen in rats. Acetaminophen (100 mg/kg, p.o) was administered to rats for nine consecutive days. On days 4-9, K. parviflora extract (250 mg/kg, p.o) was given to the acetaminophen-treated rats. After co-administration with K. parviflora, the concentrations of acetaminophen during day 5-8 markedly decreased compared with acetaminophen-only group. At day 9, the pharmacokinetic parameters of acetaminophen in the presence of K. parviflora extract also decreased, including area under the concentration-time curve (from 1.68 ± 0.16 to 0.34 ± 0.04 mg.min/mL), the maximum concentration (from 19.10 ± 1.90 to 4.48 ± 0.56 µg/mL), and half-life (from 21.29 ± 1.36 to 10.81 ± 1.24 min). In addition, clearance and the elimination rate constant of acetaminophen were significantly increased (from 0.003 ± 0.000 to 0.006 ± 0.001 L/min and 0.03 ± 0.00 to 0.07 ± 0.01 min^-1, respectively) in the presence of K. parviflora extract. These findings provide the data for in vivo herb-drug interaction between K. parviflora extract and acetaminophen. Therefore, the concomitant use of K. parviflora as a food supplement and acetaminophen should occasion therapeutic and safety concerns.

Toxicological evaluation of standardized Kaempferia parviflora extract: Sub-chronic and mutagenicity studies

Kaempferia parviflora (KP), also known as Krachai-dam in Thailand, belongs to the family Zingiberaceae and has been used traditionally to improve blood flow and treat inflammatory, allergic, and gastrointestinal disorders. The objective of this study was to investigate the safety profile of a standardized hydroalcoholic KP rhizome extract via mutagenicity and sub-chronic toxicity evaluations using in vitro and in vivo techniques. The in vitro mutagenicity of KP extract was assessed via reverse mutation tests using Salmonella typhimurium TA98, TA100, TA1535, and TA1537, and Escherichia coli WP2 uvrA. The sub-chronic toxicity profile was evaluated after daily oral administration of KP extract to Sprague-Dawley rats for 90 days. General toxicological parameters were monitored weekly. After the treatment period, blood was collected for hematological and biochemical analyses and certain organs were removed for macroscopic and histopathological analyses. Reverse mutation tests revealed that KP extract did not induce gene mutations at any of the concentrations tested. In the sub-chronic toxicity test, a few changes were observed, including increased salivation in the animals administered high-dose KP extract (249 mg/kg body weight (bw)/day). No toxicologically relevant changes were observed in the biochemical analysis. Sub-chronic administration of KP extract increased platelet levels in animals administered low-dose KP extract (25 mg/kg bw/day). However, the hematological and biochemical parameters remained within normal physiological ranges for the animal species. No toxicological changes were observed in the macroscopic and histopathological analyses performed in this study. These results demonstrate that KP extract is not genotoxic and that 90-day oral administration of the doses tested did not result in toxicity. Therefore, KP extract has a high safety margin for daily use.

Glucose Tolerance Test and Pharmacokinetic Study of Kaempferia parviflora Extract in Healthy Subjects

Kaempferia parviflora Wall. ex Baker (KP), Krachaidam in Thai or Thai ginseng, is a herbal medicine that has many potential pharmacological effects. The effect of KP extract on blood glucose level in rodent was reported. This study focused on the oral glucose tolerance test and pharmacokinetic study in healthy volunteers administered with KP extract (90 and 180 mg/day, placebo). The oral glucose tolerance tests were performed at baselines and 28-days of administration. The pharmacokinetics were determined after a single dose administration of the tested products using 3,5,7,3′,4′-pentamethoxyflavone (PMF) and 5,7,4′-trimethoxylflavone (TMF) as markers. The results showed that glucose metabolism via oral glucose tolerance test was not affected by KP extract. Blood glucose levels of volunteers at 120 min after glucose loading were able to be returned to initial levels in placebo, KP 90 mg/day, and KP 180 mg/day groups both at baseline and 28-days of administration. The results of the pharmacokinetic study revealed that only TMF and PMF, but not 5,7-dimethoxyflavone (DMF) levels could be detected in human blood. The given doses of KP extract at 90 and 180 mg/day showed a linear dose-relationship of blood PMF concentration whereas blood TMF was detected only at high given dose (180 mg/day). The half-lives of PMF and TMF were 2–3 h. The maximum concentration (C_max), area under the curve of blood concentration and time (AUC), and time to maximum concentration (T_max) values of PMF and TMF estimated for the 180 mg/day dose were 71.2 ± 11.3, 63.0 ± 18.0 ng/mL; 291.9 ± 48.2, 412.2 ± 203.7 ng∙h/mL; and 4.02 ± 0.37, 6.03 ± 0.96 h, respectively. PMF was quickly eliminated with higher Ke and Cl than TMF at the dose of 180 mg/day of KP extract. In conclusion, the results demonstrated that KP extract had no effect on the glucose tolerance test. In addition, this is the first demonstration of the pharmacokinetic parameters of methoxyflavones of KP extract in healthy volunteers. The data suggest the safety of the KP extract and will be of benefit for further clinical trials using KP extract as food and sport supplements as well as a drug in health product development.

Kaempferia parviflora Ethanol Extract, a Peroxisome Proliferator-Activated Receptor γ Ligand-binding Agonist, Improves Glucose Tolerance and Suppresses Fat Accumulation in Diabetic NSY Mice

This study assessed the effect of Kaempferia parviflora, also known as black ginger (BG), and its ethanol extract (BGE) on peroxisome proliferator-activated receptor (PPAR) γ agonistic activity, glucose tolerance, fat accumulation, and lipids-induced hypertriglyceridemia in mice. PPARγ ligand-binding capacity in vitro and polymethoxy flavone contents were highly observed in organic solvent extracts. In an animal experiment A, male diabetic Nagoya-Shibata-Yasuda mice were divided into five dietary groups and fed each diet for 8 weeks: AIN-93G diet (low-fat [LF] diet), high-fat (HF) diet, HF diet supplemented with 1% BG, HF diet supplemented with 0.19% BGE, and HF diet supplemented with pioglitazone (PPARγ agonist, 3 mg/kg/day) as a PPARγ agonistic positive control. As determined from glucose and insulin tolerance tests, plasma glucose levels were improved in the BG and BGE groups. The BGE extract suppressed fat accumulation in adipose tissues, liver, and muscles without changing the plasma adiponectin level. In an animal experiment B, in order to investigate the effect of BG and BGE on lipid-induced hypertriglyceridemia, male ddY mice were divided into three test groups: control, BG-administered group (500 mg/kg), and BGE-administered group (100 mg/kg). The plasma triacylglycerol level was not different among the groups during the lipids administration test. These results conclude that the BGE extract containing several kinds of polymethoxy flavones showed PPARγ ligand-binding capacity in vitro and prevented obesity and insulin resistance independent of adiponectin secretion in mice. PRACTICAL APPLICATION: Kaempferia parviflora, also known as black ginger (BG), is often used as a folk medicine and a functional food material to prevent metabolic syndrome mainly in Asian regions. Here, we have clarified that ethanol extract from BG (BGE) contains several kinds of polymethoxy flavones to show PPARγ ligand-binding capacity and is an active extract for the improvement of obesity and insulin resistance. The BGE is expected to be applied for functional food materials in health food markets. Also, polymethoxy flavones to show PPARγ ligand-binding capacity can be generally applied as a physiological active compound of functional food supplements.

Activation of Human Brown Adipose Tissue by Capsinoids, Catechins, Ephedrine, and Other Dietary Components: A Systematic Review

Human brown adipose tissue (BAT) has attracted clinical interest not only because it dissipates energy but also for its potential capacity to counteract obesity and related metabolic disorders (e.g., insulin resistance and dyslipidemia). Cold exposure is the most powerful stimulus for activating and recruiting BAT, and this stimulatory effect is mediated by the transient receptor potential (TRP) channels. BAT can also be activated by other receptors such as the G-protein-coupled bile acid receptor 1 (GPBAR1) or β-adrenergic receptors. Interestingly, these receptors also interact with several dietary components; in particular, capsinoids and tea catechins appear to mimic the effects of cold through a TRP-BAT axis, and they consequently seem to decrease body fat and improve metabolic blood parameters. This systematic review critically addresses the evidence behind the available human studies analyzing the effect of several dietary components (e.g., capsinoids, tea catechins, and ephedrine) on BAT activity. Even though the results of these studies are consistent with the outcomes of preclinical models, the lack of robust study designs makes it impossible to confirm the BAT-activation capacity of the specified dietary components. Further investigation into the effects of dietary components on BAT is warranted to clarify to what extent these components could serve as a powerful strategy to treat obesity and related metabolic disorders.

Translational Pharmacology and Physiology of Brown Adipose Tissue in Human Disease and Treatment

Human brown adipose tissue (BAT) is experimentally modeled to better understand the biology of this important metabolic tissue, and also to enable the potential discovery and development of novel therapeutics for obesity and sequelae resulting from the persistent positive energy balance. This chapter focuses on translation into humans of findings and hypotheses generated in nonhuman models of BAT pharmacology. Given the demonstrated challenges of sustainably reducing caloric intake in modern humans, potential solutions to obesity likely lie in increasing energy expenditure. The energy-transforming activities of a single cell in any given tissue can be conceptualized as a flow of chemical energy from energy-rich substrate molecules into energy-expending, endergonic biological work processes through oxidative degradation of organic molecules ingested as nutrients. Despite the relatively tight coupling between metabolic reactions and products, some expended energy is incidentally lost as heat, and in this manner a significant fraction of the energy originally captured from the environment nonproductively transforms into heat rather than into biological work. In human and other mammalian cells, some processes are even completely uncoupled, and therefore purely energy consuming. These molecular and cellular actions sum up at the physiological level to adaptive thermogenesis, the endogenous physiology in which energy is nonproductively released as heat through uncoupling of mitochondria in brown fat and potentially skeletal muscle. Adaptive thermogenesis in mammals occurs in three forms, mostly in skeletal muscle and brown fat: shivering thermogenesis in skeletal muscle, non-shivering thermogenesis in brown fat, and diet-induced thermogenesis in brown fat. At the cellular level, the greatest energy transformations in humans and other eukaryotes occur in the mitochondria, where creating energetic inefficiency by uncoupling the conversion of energy-rich substrate molecules into ATP usable by all three major forms of biological work occurs by two primary means. Basal uncoupling occurs as a passive, general, nonspecific leak down the proton concentration gradient across the membrane in all mitochondria in the human body, a gradient driving a key step in ATP synthesis. Inducible uncoupling, which is the active conduction of protons across gradients through processes catalyzed by proteins, occurs only in select cell types including BAT. Experiments in rodents revealed UCP1 as the primary mammalian molecule accounting for the regulated, inducible uncoupling of BAT, and responsive to both cold and pharmacological stimulation. Cold stimulation of BAT has convincingly translated into humans, and older clinical observations with nonselective 2,4-DNP validate that human BAT's participation in pharmacologically mediated, though nonselective, mitochondrial membrane decoupling can provide increased energy expenditure and corresponding body weight loss. In recent times, however, neither beta-adrenergic antagonism nor unselective sympathomimetic agonism by ephedrine and sibutramine provide convincing evidence that more BAT-selective mechanisms can impact energy balance and subsequently body weight. Although BAT activity correlates with leanness, hypothesis-driven selective β3-adrenergic agonism to activate BAT in humans has only provided robust proof of pharmacologic activation of β-adrenergic receptor signaling, limited proof of the mechanism of increased adaptive thermogenesis, and no convincing evidence that body weight loss through negative energy balance upon BAT activation can be accomplished outside of rodents. None of the five demonstrably β3 selective molecules with sufficient clinical experience to merit review provided significant weight loss in clinical trials (BRL 26830A, TAK 677, L-796568, CL 316,243, and BRL 35135). Broader conclusions regarding the human BAT therapeutic hypothesis are limited by the absence of data from most studies demonstrating specific activation of BAT thermogenesis in most studies. Additionally, more limited data sets with older or less selective β3 agonists also did not provide strong evidence of body weight effects. Encouragingly, β3-adrenergic agonists, catechins, capsinoids, and nutritional extracts, even without robust negative energy balance outcomes, all demonstrated increased total energy expenditure that in some cases could be associated with concomitant activation of BAT, though the absence of body weight loss indicates that in no cases did the magnitude of negative energy balance reach sufficient levels. Glucocorticoid receptor agonists, PPARg agonists, and thyroid hormone receptor agonists all possess defined molecular and cellular pharmacology that preclinical models predicted to be efficacious for negative energy balance and body weight loss, yet their effects on human BAT thermogenesis upon translation were inconsistent with predictions and disappointing. A few new mechanisms are nearing the stage of clinical trials and may yet provide a more quantitatively robust translation from preclinical to human experience with BAT. In conclusion, translation into humans has been demonstrated with BAT molecular pharmacology and cell biology, as well as with physiological response to cold. However, despite pharmacologically mediated, statistically significant elevation in total energy expenditure, translation into biologically meaningful negative energy balance was not achieved, as indicated by the absence of measurable loss of body weight over the duration of a clinical study.

Kaempferia parviflora and Its Methoxyflavones: Chemistry and Biological Activities

Kaempferia parviflora (KP), a health-promoting herb, has been traditionally used for treating a variety of diseases. Pharmacological studies have claimed the various benefits from KP and its main effective methoxyflavones, including cellular metabolism-regulating activity, anticancer activity, vascular relaxation and cardioprotective activity, sexual enhancing activity, neuroprotective activity, antiallergic, anti-inflammatory, and antioxidative activity, antiosteoarthritis activity, antimicroorganism activity, and transdermal permeable activity. These might be associated with increased mitochondrial functions and activated cGMP-NO signaling pathway. However, the underlying molecular mechanisms of KP and its methoxyflavones are still under investigation. The clinical applications of KP and its methoxyflavones may be limited due to their low bioavailability. But promising strategies are on the way. This review will comprehensively discuss the biological activities of KP and its methoxyflavones.

Effect of the active ingredient of Kaempferia parviflora, 5,7-dimethoxyflavone, on the pharmacokinetics of midazolam

5,7-Dimethoxyflavone (5,7-DMF), one of the major components of Kaempferia parviflora, has anti-obesity, anti-inflammatory, and antineoplastic effects. On the other hand, in vitro studies have reported that it directly inhibits the drug metabolizing enzyme family cytochrome P450 (CYP) 3As. In this study, its safety was evaluated from a pharmacokinetic point of view, based on daily ingestion of 5,7-DMF. Midazolam, a substrate of CYP3As, was orally administered to mice treated with 5,7-DMF for 10 days, and its pharmacokinetic properties were investigated. In the group administered 5,7-DMF, the area under the curve (AUC) of midazolam increased by 130% and its biological half-life was extended by approximately 100 min compared to the control group. Compared to the control group, 5,7-DMF markedly decreased the expression of CYP3A11 and CYP3A25 in the liver. These results suggest that continued ingestion of 5,7-DMF decreases the expression of CYP3As in the liver, consequently increasing the blood concentrations of drugs metabolized by CYP3As.

Food-derived regulatory factors against obesity and metabolic syndrome

Obesity is a key factor in metabolic syndrome. The study of metabolic syndrome focuses on the anti-weight gain properties of physiological mechanisms and food components. Abnormal energy metabolism is a major risk factor of metabolic syndrome. Chronic inflammation is a feature of obesity; cytokines from hypertrophied adipocytes cause inflammation in both adipose tissue and blood vessels, resulting in symptoms of metabolic syndrome. Tumor necrosis factor-α causes insulin resistance in adipocytes and regression of brown adipocytes, resulting in abnormal energy metabolism. Functional foods can serve as a strategy for prevention and treatment of obesity linked with metabolic processes in white and brown adipose tissues. Diet-induced thermogenesis caused by certain food components stimulates burning of stored fat within adipose tissues. A mechanistic understanding of dietary thermogenesis via the sympathetic nerve system will prove valuable for the development of precise strategies for the practical prevention of metabolic syndrome.

Daily intake of Kaempferia parviflora extract decreases abdominal fat in overweight and preobese subjects: a randomized, double-blind, placebo-controlled clinical study

PURPOSE

Obesity is a serious problem, which is now a worldwide health problem. Kaempferia parviflora extract (KPE) exhibits anti-obesity effects in animals. However, as no clinical trials have evaluated the anti-obesity effects of KPE in humans, we examined the effects of KPE in reducing abdominal fat in overweight and preobese Japanese subjects.

MATERIALS AND METHODS

A 12-week, single-center, randomized, double-blind, placebo-controlled clinical trial was conducted. Seventy-six subjects (males and females aged 20 to <65 years) with a body mass index ≥24 and <30 kg/m² were randomly assigned into two groups. The subjects in each group ingested one capsule of placebo or active KPE (containing 150 mg of KPE) once daily for 12 weeks. The primary outcome was reduction in visceral fat area as determined by computed tomography scanning. The key secondary outcomes were reductions in subcutaneous fat area and total fat area. Subgroup analysis was also performed in healthy subjects without dyslipidemia, hypertension, or hyperglycemia. The safety of KPE ingestion was also evaluated.

RESULTS

Compared with the placebo group, the active KPE group exhibited significant reduction in abdominal fat area (visceral, subcutaneous, and total fat) and triglyceride levels after 12 weeks. Subgroup analyses demonstrated a significant reduction in abdominal fat area and triglyceride levels in healthy subjects compared with the placebo group after 12 weeks. Neither group exhibited adverse events related to the test foods or clinically relevant abnormal changes in physical, biochemical, or hematologic parameters, or in urinalysis results and medical interview.

CONCLUSION

Daily ingestion of KPE safely reduces body fat, particularly abdominal fat, in Japanese overweight and preobese subjects.

Difference in intracellular temperature rise between matured and precursor brown adipocytes in response to uncoupler and β-adrenergic agonist stimuli

Brown adipocytes function to maintain body temperature by heat production. However, direct measurement of heat production at a single cell level remains difficult. Here we developed a method to measure the temperature within primary cultured brown adipocytes using a cationic fluorescent polymeric thermometer. Placement of the thermometer within a matured brown adipocyte and a precursor cell enabled the detection of heat production following uncoupler treatment. The increase in the intracellular temperature due to stimulation with a mitochondrial uncoupler was higher in matured brown adipocytes than in precursor cells. Stimulation with a β-adrenergic receptor (β-AR) agonist, norepinephrine, raised the intracellular temperature of matured brown adipocytes to a level comparable to that observed after stimulation with a β3-AR-specific agonist, CL316.243. In contrast, neither β-AR agonist induced an intracellular temperature increase in precursor cells. Further, pretreatment of brown adipocytes with a β3-AR antagonist inhibited the norepinephrine-stimulated elevation of temperature. These results demonstrate that our novel method successfully determined the difference in intracellular temperature increase between matured brown adipocytes and precursor cells in response to stimulation by an uncoupler and β-AR agonists.

Effect of Kaempferia parviflora extract on knee osteoarthritis

Knee osteoarthritis (OA) is becoming more prevalent worldwide due to increases in the numbers of elderly and obese patients. Currently, pharmaceutical medicines used for the treatment of OA are for symptomatic therapy and therefore new therapeutic agents are needed. Kaempferia parviflora (KP) is a plant growing naturally in Southeast Asia and has various pharmacological effects including an anti-inflammatory effect, but no effect on OA has yet been reported. We therefore conducted a search for the effects KP and the active components of KP extract (KPE) exert on OA as well as its mechanism of action. Results from a study of KPE using the monoiodoacetic acid rat OA model revealed that KPE reduced the pain threshold and severity of osteoarthritic cartilage lesions. The mechanism of action and active components were then investigated using IL-1β-treated human knee-derived chondrocytes. KPE, as well as 5,7-dimethoxyflavone and 5,7,4'-trimethoxyflavone, which are key constituents of KPE and highly absorbable into the body, reduced the expression of matrix metalloproteinases (MMPs), which are the main extracellular matrix enzymes that degrade collagen within cartilage. As mentioned above, KPE acted to suppress OA and 5,7-dimethoxyflavone and 5,7,4'-trimethoxyflavone were shown to be involved as part of KPE's mechanism that inhibits MMPs.

Effect of Kaempferia parviflora on sexual performance in streptozotocin-induced diabetic male rats

Kaempferia parviflora Wall. Ex.Baker or Krachidum (KP) has been used locally in medicine and food. It has been claimed that KP has aphrodisia properties; however, no scientific data in support of this function in diabetic model have been reported. This study aimed to investigate the efficacy of KP on sexual behaviour and sperm parameter in streptozotocin (STZ)-induced diabetic male rats. Diabetes was induced in twenty male rats by STZ and divided into four groups: diabetic control group, and 3 treatment groups where KP was dose at 140, 280 and 420 mg/kg orally once a day for 6 weeks. Five normal control rats were treated with vehicle. The body weight, blood glucose, food intake, epididymal sperm parameter, sexual behaviour and serum testosterone level were evaluated. The results showed that KP treatment has no effect on the body weight, blood glucose and food intake in diabetic rats. A significant increase in sperm density in diabetic rats was observed (p < .05) at highest dose of KP. Furthermore, KP treatment demonstrated a significant recovery of sexual behaviour and serum testosterone levels in diabetic rats. These results confirm that KP exhibits aphrodisiac properties that improve the sperm density, testosterone level and sexual performance of STZ-induced diabetic rats.

Clinical Effects of Krachaidum ( Kaempferia parviflora): A Systematic Review

Kaempferia parviflora (Krachaidum) is a medicinal plant in the family Zingiberaceae. Its rhizome has been used as folk medicine for many centuries. A number of pharmacological studies of Krachaidum had claimed benefits for various ailments. Therefore, this study aimed to systematically search and summarize the clinical evidences of Krachaidum in all identified indications. Of 683 records identified, 7 studies were included. From current clinical trials, Krachaidum showed positive benefits but remained inconclusive since small studies were included. Even though results found that Krachaidum significantly increased hand grip strength and enhanced sexual erotic stimuli, these were based on only 2 studies and 1 study, respectively. With regard to harmful effects, we found no adverse events reported even when Krachaidum 1.35 g/day was used. Therefore, future studies of Krachaidum are needed with regards to both safety and efficacy outcomes.

Increased vascular eNOS and cystathionine-γ-lyase protein after 6 weeks oral administration of 3, 5, 7, 3', 4'-pentamethoxyflavone to middle-aged male rats

Effects of treatment of middle-aged male rats with 3, 5, 7, 3', 4'-pentamethoxyflavone (PMF) on vascular and perivascular adipose tissue (PVAT) functions and blood chemistry were investigated. Rats received PMF (22 mg/kg), orally or vehicle, twice a day for 6 weeks. The PMF-treated rats had lower serum glucose, higher HDL-C levels, but no change in other parameters. Thoracic aortic and mesenteric rings of PMF treated rats produced lower maximal contraction to phenylephrine that was normalized by N^G-nitro-L-arginine (L-NA) or endothelial removal. The aortic- and mesenteric rings of the PMF treated rats showed improved relaxation to acetylcholine, but not to glyceryl trinitrate, and had higher eNOS protein. DL-propargylglycine (PAG) caused greater increase in the baseline tension of the PMF-treated aortic ring and higher contraction to low concentrations of phenylephrine. PVAT lowered the contractile response of the L-NA pretreated aortic rings to phenylephrine for both groups, but PAG had no effect. The cystathionine-γ-lyase (CSE) protein of the thoracic rings, but not of the PVAT, shows increased expression after PMF treatment. Overall, PMF treatment of middle aged rats appeared to increase production of NO and H₂S from the blood vessels by upregulating the expression of eNOS and CSE. PMF also decreased fasting serum glucose and increased HDL-C levels, with no toxicity to liver and kidney functions. Thus, PMF is a novel compound for possible use as a health product to prevent and/or to reduce the development of diabetes type II and/or cardiovascular disease.

Black ginger extract increases physical fitness performance and muscular endurance by improving inflammation and energy metabolism

We previously reported that polymethoxyflavones (PMFs) in black ginger (Kaempferia parviflora) extract (KPE) increased energy production by activating AMP-activated protein kinase (AMPK) in C2C12 myoblasts. We herein evaluated the effects of KPE on physical fitness performance and muscular endurance in mice. Male mice were orally administered KPE for 4 weeks, and then forced swimming test, open-field test, inclined plane test, and wire hanging test were performed. KPE significantly increased the swimming time, motility after swimming, and grip strength. IL-6 and TNF-α mRNA expression levels were decreased in the soleus muscle, whereas peroxisome proliferator-activated receptor γ coactivator (PGC)-1α and glycogen synthase mRNA expression levels, mitochondrial number, and glycogen content were increased. These results were in agreement with those obtained for KPE and PMFs in C2C12. Therefore, the activation of AMPK by PMFs may be one of the mechanisms by which KPE improves physical fitness performance and muscular endurance.

Enhancement of energy production by black ginger extract containing polymethoxy flavonoids in myocytes through improving glucose, lactic acid and lipid metabolism

Enhancement of muscular energy production is thought to improve locomotive functions and prevent metabolic syndromes including diabetes and lipidemia. Black ginger (Kaempferia parviflora) has been cultivated for traditional medicine in Thailand. Recent studies have shown that black ginger extract (KPE) activated brown adipocytes and lipolysis in white adipose tissue, which may cure obesity-related dysfunction of lipid metabolism. However, the effect of KPE on glucose and lipid utilization in muscle cells has not been examined yet. Hence, we evaluated the effect of KPE and its constituents on energy metabolism in pre-differentiated (p) and differentiated (d) C2C12 myoblasts. KPE (0.1-10 μg/ml) was added to pC2C12 cells in the differentiation process for a week or used to treat dC2C12 cells for 24 h. After culturing, parameters of glucose and lipid metabolism and mitochondrial biogenesis were assessed. In terms of the results, KPE enhanced the uptake of 2-deoxyglucose and lactic acid as well as the mRNA expression of glucose transporter (GLUT) 4 and monocarboxylate transporter (MCT) 1 in both types of cells. The expression of peroxisome proliferator-activated receptor γ coactivator (PGC)-1α was enhanced in pC2C12 cells. In addition, KPE enhanced the production of ATP and mitochondrial biogenesis. Polymethoxy flavonoids in KPE including 5-hydroxy-7-methoxyflavone, 5-hydroxy-3,7,4'-trimethoxyflavone and 5,7-dimethoxyflavone enhanced the expression of GLUT4 and PGC-1α. Moreover, KPE and 5,7-dimethoxyflavone enhanced the phosphorylation of 5'AMP-activated protein kinase (AMPK). In conclusion, KPE and its polymethoxy flavonoids were found to enhance energy metabolism in myocytes. KPE may improve the dysfunction of muscle metabolism that leads to metabolic syndrome and locomotive dysfunction.

Matured hop extract reduces body fat in healthy overweight humans: a randomized, double-blind, placebo-controlled parallel group study

Background

Hops are the main components of beer that provide flavor and bitterness. Iso-α-acids, the bitter components of beer, have been reported to reduce body fat in humans, but the bitterness induced by effective doses of iso-α-acids precludes their acceptance as a nutrient. The matured hop bitter acids (MHBA) of oxidized hops appear to have a more pleasant bitterness compared to the sharper bitterness of iso-α-acids. While there has been little information concerning the identity of the MHBA compounds and their physiological effects, MHBA was recently found to be primarily composed of oxides derived from α-acids, and structurally similar to iso-α-acids. Here, we investigated the effects of matured hop extract (MHE) containing MHBA on reducing abdominal body fat in healthy subjects with a body mass index (BMI) of 25 to below 30 kg/m², classified as “obese level 1” in Japan or as “overweight” by the WHO.

Trial design

A randomized, double-blind, placebo-controlled parallel group study.

Methods

Two hundred subjects (male and female aged 20 to below 65 years with a BMI of 25 or more and less than 30 kg/m²) were randomly assigned to two groups. During a 12-week ingestion period, the subjects in each group ingested daily 350 mL of test-beverage, either containing MHE (with 35 mg MHBA), i.e. the namely active beverage, or a placebo beverage without MHE. The primary endpoint was reduction of the abdominal fat area as determined by CT scanning after continual ingestion of MHE for 12 weeks.

Results

Compared to the placebo group, a significant reduction was observed in the visceral fat area after 8 and 12 w, and in the total fat area after 12 w in the active group. There was also a concomitant decrease in body fat ratio in the active group compared to the placebo group. No adverse events related to the test beverages or clinically relevant abnormal changes in the circulatory, blood and urine parameters were observed in either group.

Conclusions

The present study suggests that continual ingestion of MHE safely reduces body fat, particularly the abdominal visceral fat of healthy overweight subjects.

Trial registration

UMIN-CTR UMIN000014185

Electronic supplementary material

The online version of this article (doi:10.1186/s12937-016-0144-2) contains supplementary material, which is available to authorized users.