The effect of (-)-hydroxycitrate on energy intake and satiety in overweight humans

Hydroxycitrate delays early mortality in mice and promotes muscle regeneration while inducing a rich hepatic energetic status

ATP citrate lyase (ACLY) inhibitors have the potential of modulating central processes in protein, carbohydrate, and lipid metabolism, which can have relevant physiological consequences in aging and age-related diseases. Here, we show that hepatic phospho-active ACLY correlates with overweight and Model for End-stage Liver Disease score in humans. Wild-type mice treated chronically with the ACLY inhibitor potassium hydroxycitrate exhibited delayed early mortality. In AML12 hepatocyte cultures, the ACLY inhibitors potassium hydroxycitrate, SB-204990, and bempedoic acid fostered lipid accumulation, which was also observed in the liver of healthy-fed mice treated with potassium hydroxycitrate. Analysis of soleus tissue indicated that potassium hydroxycitrate produced the modulation of wound healing processes. In vivo, potassium hydroxycitrate modulated locomotor function toward increased wire hang performance and reduced rotarod performance in healthy-fed mice, and improved locomotion in mice exposed to cardiotoxin-induced muscle atrophy. Our findings implicate ACLY and ACLY inhibitors in different aspects of aging and muscle regeneration.

Tropical foods as functional foods for metabolic syndrome

Tropical foods are an integral part of the traditional diet and form part of traditional medicine in many countries. This review examines the potential of tropical foods to treat signs of metabolic syndrome, defined as a chronic low-grade inflammation leading to obesity, hypertension, impaired glucose tolerance, insulin resistance, dyslipidaemia and fatty liver. It is a major risk factor for cardiovascular and metabolic disease as well as osteoarthritis and some cancers. Tropical foods such as seaweeds and tropical fruits including indigenous fruits such as Davidson's plums are effective in reducing these signs of metabolic syndrome in rats, as well as reducing degeneration of bone cartilage and altering gut microbiome. Further, waste products from tropical fruits including mangosteen rind, coffee pulp and spent coffee grounds provide further options to reduce metabolic syndrome. Production of local tropical foods and local recovery of food waste from these foods could allow the development of commercial, sustainable and cost-effective functional foods in tropical countries. The aim is to develop these functional foods to reduce the incidence of metabolic syndrome and decrease the risk of costly chronic cardiovascular and metabolic disorders locally and globally.

Nutrition Supplements to Stimulate Lipolysis: A Review in Relation to Endurance Exercise Capacity

Athletes make great efforts to increase their endurance capacity in many ways. Using nutrition supplements for stimulating lipolysis is one such strategy to improve endurance performance. These supplements contain certain ingredients that affect fat metabolism; furthermore, in combination with endurance training, they tend to have additive effects. A large body of scientific evidence shows that nutrition supplements increase fat metabolism; however, the usefulness of lipolytic supplements as ergogenic functional foods remains controversial. The present review will describe the effectiveness of lipolytic supplements in fat metabolism and as an ergogenic aid for increasing endurance exercise capacity. There are a number of lipolytic supplements available on the market, but this review focuses on natural ingredients such as caffeine, green tea extract, L-carnitine, Garcinia cambogia (hydroxycitric acid), capsaicin, ginseng, taurine, silk peptides and octacosanol, all of which have shown scientific evidence of enhancing fat metabolism associated with improving endurance performance. We excluded some other supplements owing to lack of data on fat metabolism or endurance capacity. Based on the data in this review, we suggest that a caffeine and green tea extract improves endurance performance and enhances fat oxidation. Regarding other supplements, the data on their practical implications needs to be gathered, especially for athletes.

(-)-Hydroxycitric acid reduced fat deposition via regulating lipid metabolism-related gene expression in broiler chickens

BACKGROUND

Chicken as a delicious food for a long history, and it is well known that excess fat deposition in broiler chickens will not only induced metabolic diseases, but also lead to adverse effect in the consumer's health. (-)-Hydroxycitric acid (HCA), a major active ingredient of Garcinia Cambogia extracts, had shown to suppress fat accumulation in animals and humans. While, the precise physiological mechanism of HCA has not yet been full clarified, especially its action in broiler chickens. Thus, this study aimed to assess the effect of (-)-HCA on lipid metabolism in broiler chickens.

METHODS

A total of 120 1-day-old broiler chickens were randomly allocated to four groups, with each group was repeated three times with 10 birds. Birds received a commercial diet supplemented with (-)-HCA at 0, 1000, 2000 or 3000 mg/kg, respectively, for a period of 4 weeks ad libitum.

RESULTS

Body weight (BW) in the 2000 and 3000 mg/kg (-)-HCA groups was significantly decreased (P < 0.05) than that in control group. A significantly decreased of serum triglyceride (TG) and density lipoprotein-cholesterol (LDL-C) content were observed in 3000 mg/kg (-)-HCA group (P < 0.05). Broiler chickens supplmented with 2000 and 3000 mg/kg (-)-HCA had pronouncedly higher hepatic lipase (HL) activity, hepatic glycogen and non-esterified fatty acid (NEFA) contents in liver (P < 0.05). Serum free triiodothyronine (FT3) and thyroxin (T4) contents were significantly higher in 3000 mg/kg (-)-HCA group (P < 0.05) compared with the control group. Supplemental (-)-HCA markedly decreased fatty acid synthase (FAS) and sterol regulatory element binding protein-1c (SREBP-1c) (P < 0.05) mRNA levels, while the mRNA abundance of adenosine 5'-monophosphate-activated protein kinaseβ2 (AMPKβ2) (P < 0.05) was significantly increased. In addition, ATP-citrate lyase (ACLY) mRNA level (P < 0.05) was significantly decreased in broiler chickens supplemented with 3000 mg/kg (-)-HCA. No differences was observed on carnitine palmitoyl transferase-I(CPT-I), while peroxisome proliferators-activated receptor α (PPARα) mRNA level (P < 0.05) was significantly increased in broiler chickens supplemented with 2000 and 3000 mg/kg (-)-HCA.

CONCLUSIONS

Supplemental (-)-HCA inhibited lipogenesis by inhibiting ACLY, SREBP-1c and FAS expression, and accelerated lipolysis through enhancing HL activity and PPARα expression, which eventually led to the reduced abdominal fat deposition in broiler chickens. Graphical abstract Mechanism of (-)-HCA effect on hepatic lipids metabolism.

Effects of postweaning administration of conjugated linoleic acid on development of obesity in nescient basic helix-loop-helix 2 knockout mice

Conjugated linoleic acid (CLA) has been reported to prevent body weight gain and fat accumulation in part by improving physical activity in mice. However, the effects of postweaning administration of CLA on the development of obesity later in life have not yet been demonstrated. The current study investigated the role of postweaning CLA treatment on skeletal muscle energy metabolism in genetically induced inactive adult-onset obese model, nescient basic helix-loop-helix 2 knockout (N2KO) mice. Four-week-old male N2KO and wild type mice were fed either control or a CLA-containing diet (0.5%) for 4 weeks, and then CLA was withdrawn and control diet provided to all mice for the following 8 weeks. Postweaning CLA supplementation in wild type animals, but not N2KO mice, may activate AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor-δ (PPARδ) as well as promote desensitization of phosphatase and tensin homologue (PTEN) and sensitization of protein kinase B (AKT) at threonine 308 in gastrocnemius skeletal muscle, improving voluntary activity and glucose homeostasis. We suggest that postweaning administration of CLA may in part stimulate the underlying molecular targets involved in muscle energy metabolism to reduce weight gain in normal animals, but not in the genetically induced inactive adult-onset animal model.

Updates on Antiobesity Effect of Garcinia Origin (-)-HCA

Garcinia is a plant under the family of Clusiaceae that is commonly used as a flavouring agent. Various phytochemicals including flavonoids and organic acid have been identified in this plant. Among all types of organic acids, hydroxycitric acid or more specifically (−)-hydroxycitric acid has been identified as a potential supplement for weight management and as antiobesity agent. Various in vivo studies have contributed to the understanding of the anti-obesity effects of Garcinia/hydroxycitric acid via regulation of serotonin level and glucose uptake. Besides, it also helps to enhance fat oxidation while reducing de novo lipogenesis. However, results from clinical studies showed both negative and positive antiobesity effects of Garcinia/hydroxycitric acid. This review was prepared to summarise the update of chemical constituents, significance of in vivo/clinical anti-obesity effects, and the importance of the current market potential of Garcinia/hydroxycitric acid.

In vitro and in vivo toxicity of garcinia or hydroxycitric Acid: a review

Obesity is one of the pandemic chronic diseases commonly associated with health disorders such as heart attack, high blood pressure, diabetes or even cancer. Among the current natural products for obesity and weight control, Garcinia or more specifically hydroxycitric acid (HCA) extracted from Garcinia has been widely used. The evaluation of the potential toxicity of weight control supplement is of the utmost importance as it requires long term continuous consumption in order to maintain its effects. Majority of reports demonstrated the efficacy of Garcinia/HCA without any toxicity found. However, a few clinical toxicity reports on weight-loss diet supplements of which some were combinations that included Garcinia/HCA as an active ingredient showed potential toxicity towards spermatogenesis. Nonetheless, it cannot be concluded that Garcinia/HCA is unsafe. Those products which have been reported to possess adverse effects are either polyherbal or multi-component in nature. To date, there is no case study or report showing the direct adverse effect of HCA. The structure, mechanism of action, long history of the use of Garcinia/HCA and comprehensive scientific evidence had shown “no observed adverse effect level (NOAEL)” at levels up to 2800 mg/day, suggesting its safety for use.

The Use of Garcinia Extract (Hydroxycitric Acid) as a Weight loss Supplement: A Systematic Review and Meta-Analysis of Randomised Clinical Trials

The aim of this systematic review is to examine the efficacy of Garcinia extract, hydroxycitric acid (HCA) as a weight reduction agent, using data from randomised clinical trials (RCTs). Electronic and nonelectronic searches were conducted to identify relevant articles, with no restrictions in language or time. Two independent reviewers extracted the data and assessed the methodological quality of included studies. Twenty-three eligible trials were identified and twelve were included. Nine trials provided data suitable for statistical pooling. The meta-analysis revealed a small, statistically significant difference in weight loss favouring HCA over placebo (MD: -0.88 kg; 95% CI: -1.75, -0.00). Gastrointestinal adverse events were twice as common in the HCA group compared with placebo in one included study. It is concluded that the RCTs suggest that Garcinia extracts/HCA can cause short-term weight loss. The magnitude of the effect is small, and the clinical relevance is uncertain. Future trials should be more rigorous and better reported.

Phytochemicals in the Control of Human Appetite and Body Weight

Since obesity has grown to epidemic proportions, its effective management is a very important clinical issue. Despite the great amount of scientific effort that has been put into understanding the mechanisms that lead to overconsumption and overweight, at the moment very few approaches to weight management are effective in the long term. On the other hand, modern society is also affected by the growing incidence of eating disorders on the other side of the spectrum such as anorexia and bulimia nervosa which are equally difficult to treat. This review will try to summarise the main findings available in the literature regarding the effect of plants or plant extracts (phytochemicals) on human appetite and body weight. The majority of plant extracts are not single compounds but rather a mixture of different molecules, therefore their mechanism of action usually targets several systems. In addition, since some cellular receptors tend to be widely distributed, sometimes a single molecule can have a widespread effect. This review will attempt to describe the main phytochemicals that have been suggested to affect the homeostatic mechanisms that influence intake and body weight. Clinical data will be summarised and scientific evidence will be reviewed.

Complementary and alternative therapies for weight loss

Although many complementary therapies are promoted for the treatment of obesity, few are truly therapeutic. Evidence suggests that food containing diacylglycerol oil, acupuncture, and hypnosis are the only evidence-based complementary therapies for the treatment of obesity, and, at best, these should be used as adjuvants to the more conventional therapies of calorie restriction and exercise.

Acute effects of pharmacological modifications of fatty acid metabolism on human satiety

The role of NEFA in eating behaviour is still poorly known. Our objective was to examine whether etomoxir (ETO), an inhibitor of NEFA oxidation, or ( − )-hydroxycitrate (HCA), an inhibitor of lipogenesis which may indirectly stimulate NEFA oxidation, alters satiety. Post-lunch satiety was measured in eight normal-weight male subjects who were deprived of time cues and received on three occasions either ETO (320 mg), HCA (2 g) or placebo (PLA) in random order. Between lunch and dinner, blood was withdrawn continuously and collected every 10 min for measures of plasma concentrations of glucose, insulin, lactate, TAG, NEFA, β-hydroxybutyrate (BHB), leptin and ghrelin. Results showed that HCA began to decrease hunger and desire to eat compared to PLA and ETO 210 min after lunch and increased satiety duration compared to PLA by 70 (se23) min (P < 0·05), but did not modify energy intake at dinner. ETO did not affect any variable of satiety. HCA increased NEFA concentrations during the pre-dinner period, whereas ETO increased and decreased plasma concentrations of NEFA and BHB, respectively. Mean differences in plasma NEFA concentrations between HCA and PLA were predictive of the differences in satiety duration between treatments (r20·71,P < 0·01). Among treatments, plasma leptin concentration at dinner onset was the only blood variable correlated with energy intake at this meal (r− 0·75,P < 0·0005). In healthy, normal-weight men, acute HCA increased the intensity and duration of satiety possibly via increased NEFA disposal for oxidation.

Effect of glutamate ingestion on whole-body glutamate turnover in healthy elderly and patients with chronic obstructive pulmonary disease

OBJECTIVE

Decreased whole-body glutamate turnover is found in healthy elderly and in patients with chronic obstructive pulmonary disease (COPD). Glutamate supplementation as an option to increase whole-body glutamate turnover and, hence, glutamate availability has never been investigated. In the present study, we developed a protocol based on repeated glutamate ingestion to increase plasma glutamate concentration to a steady-state level without inducing toxic side effects and to evaluate the effect of repeated glutamate ingestion on whole-body glutamate turnover in patients with COPD and healthy elderly.

METHODS

In part 1, the response of plasma glutamate concentration was determined in young healthy volunteers who repeatedly ingested a glutamate solution. The tolerance of the glutamate drink was evaluated in 26 healthy volunteers by a food tolerance questionnaire. In part 2, eight male patients with COPD and eight healthy elderly ingested the glutamate drink, an isomolar amount of a glutamine drink, or only water to test the effect on plasma glutamate concentration and whole-body glutamate turnover.

RESULTS

In part 1, repeated ingestion of 30 mg of glutamate per kilogram of body weight every 20 min increased plasma glutamate concentration five-fold to steady-state level within 80 min and without any side effects. In part 2, repeated ingestion of glutamate significantly increased whole-body glutamate turnover in healthy controls and patients with COPD, although the increase was smaller in patients with COPD than in controls.

CONCLUSION

We found that repeated ingestion of 30 mg of glutamate per kilogram of body weight every 20 min can increase glutamate availability in healthy elderly and patients with COPD, who are likely more dependent on external glutamate ingestion than are young adults.

Multinutrient supplement containing ephedra and caffeine causes weight loss and improves metabolic risk factors in obese women: a randomized controlled trial

OBJECTIVE

To determine the safety and efficacy of a dietary supplement with a low dose of ephedra and caffeine in overweight/obese premenopausal female subjects.

DESIGN

A 9-month, double-blind, randomized control study compared the efficacy and safety of a dietary supplement with ephedra and caffeine to a control supplement.

SUBJECTS

Sixty-one healthy, premenopausal women with body mass index (BMI) from 27 to 39 kg/m2 were randomly assigned and received a dietary supplement (40 mg/day ephedra alkaloids, 100 mg/day caffeine, high potency mixture of vitamins, minerals, omega-3 fatty acids) or a control supplement for 9 months.

MEASUREMENTS

EFFICACY

changes in body weight, body composition, lipids, insulin, leptin, adiponectin, ghrelin, and self-reports of physical activity, diet and quality of life indices.

SAFETY

blood pressure, heart rate, electrocardiograms, urinalysis, blood histology, serum chemistry measures and self-reported symptoms.

RESULTS

Forty-one women completed the study. The treatment group lost significantly more body weight (-7.18 kg) and body fat (-5.33 kg) than the control group (-2.25 and -0.99 kg, respectively), and showed significant declines in heart rate, serum cholesterol, triglycerides, cholesterol to high-density lipoprotein ratio, glucose, fasting insulin, and leptin. Blood pressure, electrocardiograms, other clinical chemistry measures, blood histology, urinalysis, and self-reported physical activity were similar in the groups. Minor symptoms included dry mouth, insomnia, nervousness and palpitations. The treatment group reported more energy and decreased appetite compared to controls and scored higher on a quality of life domain assessing vitality.

CONCLUSION

A dietary supplement containing a low potency ephedra/caffeine mixture appeared safe and effective in causing loss of weight and body fat, and improving several metabolic parameters, including insulin sensitivity and lipid profiles when tested under physician supervision. Such supplements could be a useful tool to assist with weight loss.

Bioefficacy of a novel calcium-potassium salt of (-)-hydroxycitric acid

Obesity is associated with cardiovascular disease, diabetes and certain forms of cancer. Popular strategies on weight loss often fail to address many key factors such as fat mass, muscle density, bone density, water mass, their inter-relationships and impact on energy production, body composition, and overall health and well-being. (-)-Hydroxycitric acid (HCA), a natural plant extract from the dried fruit rind of Garcinia cambogia, has been reported to promote body fat loss in humans without stimulating the central nervous system. The level of effectiveness of G. cambogia extract is typically attributed solely to HCA. However, other components by their presence or absence may significantly contribute to its therapeutic effectiveness. Typically, HCA used in dietary weight loss supplement is bound to calcium, which results in a poorly soluble (<50%) and less bioavailable form. Conversely, the structural characteristics of a novel Ca2+/K+ bound (-)-HCA salt (HCA-SX or Super CitriMax) make it completely water soluble as well as bioavailable. An efficacious dosage of HCA-SX (4500 mg/day t.i.d.) provides a good source of Ca2+ (495 mg, 49.5% of RDI) and K+ (720 mg, 15% of RDI). Ca2+ ions are involved in weight management by increasing lipid metabolism, enhancing thermogenesis, and increasing bone density. K+, on the other hand, increases energy, reduces hypertension, increases muscle strength and regulates arrhythmias. Both Ca and K act as buffers in pH homeostasis. HCA-SX has been shown to increase serotonin availability, reduce appetite, increase fat oxidation, improve blood lipid levels, reduce body weight, and modulate a number of obesity regulatory genes without affecting the mitochondrial and nuclear proteins required for normal biochemical and physiological functions.

Comparison of the effects of three different (-)-hydroxycitric acid preparations on food intake in rats

Background

Studies on the effects of (-)-hydroxycitric acid (HCA) in humans are controversial. As differences in the HCA preparations may contribute to this apparent discrepancy, the aim of the current study is to compare different HCA-containing preparations in adult Wistar rats.

Design

The effects of 3 different HCA-containing preparations (Regulator, Citrin K, Super CitriMax HCA-600-SXS, all used at an effective HCA dose of 150 and 300 mg/kg, administered intragastrically) on food intake and body weight were studied in adult male Wistar rats. The efficacy was tested under 2 different experimental conditions: 1) after a single dose administration and 2) during repeated administration for 4 subsequent days.

Results

Regulator and Citrin K significantly reduced food intake in both experimental setups, while Super CitriMax HCA-600-SXS was less effective. When administered for 4 subsequent days Regulator and Citrin K diminished body weight gain.

Conclusion

Regulator and Citrin K were shown to be potent inhibitors of food intake in rats, whereas Super CitriMax HCA-600-SXS showed only small and more inconsistent effects. The striking differences in efficacy between these 3 preparations indicate that low doses of a relatively low-effective HCA preparation may have contributed to the lack of efficacy as found in several human studies.

High dose of Garcinia cambogia is effective in suppressing fat accumulation in developing male Zucker obese rats, but highly toxic to the testis

We investigated the ability of Garcinia cambogia extract containing (-)-hydroxycitric acid (HCA) to suppress body fat accumulation in developing male Zucker obese (fa/fa) rats. We also examined histopathologically the safety of its high doses. Diets containing different levels of HCA (0, 10, 51, 102 and 154 mmol/kg diet) were fed to 6-week-old rats for 92 or 93 days. Each diet group was pair-fed to the 154 mmol HCA/kg diet group. Epididymal fat accumulation and histopathological changes in tissues were observed. The highest dose of HCA-containing Garcinia cambogia (154 mmol HCA/kg diet) showed significant suppression of epididymal fat accumulation in developing male Zucker obese rats, compared with the other groups. However, the diets containing 102 mmol HCA/kg diet and higher (778 and 1244 mg HCA/kg BW/d, respectively) caused potent testicular atrophy and toxicity, whereas diets containing 51 mmol HCA/kg diet (389 mg HCA/kg BW/d) or less did not. Accordingly, 51 mmol HCA/kg diet (389 mg HCA/kg BW/d) was deemed to be the no observed adverse effect level (NOAEL).

Physico-chemical properties of a novel (-)-hydroxycitric acid extract and its effect on body weight, selected organ weights, hepatic lipid peroxidation and DNA fragmentation, hematology and clinical chemistry, and histopathological changes over a period of 90 days

Garcinia cambogia-derived (-)-hydroxycitric acid (HCA) is a popular and natural supplement for weight management. HCA is a competitive inhibitor of the enzyme ATP citrate lyase, which catalyzes the conversion of citrate and coenzyme A to oxaloacetate and acetyl coenzyme A (acetyl CoA) in the cytosol. Acetyl CoA is used in the synthesis of fatty acids, cholesterol and triglycerides, and in the synthesis of acetylcholine in the central nervous system. Studies have demonstrated the efficacy of a novel 60% calcium-potassium salt of HCA derived from Garcinia cambogia (HCA-SX, Super CitriMax) in weight management. Results have shown that HCA-SX promotes fat oxidation, enhances serotonin release and availability in the brain cortex, normalizes lipid profiles, and lowers serum leptin levels in obese subjects. Acute oral, acute dermal, primary dermal irritation and primary eye irritation toxicity, as well as Ames bacterial reverse mutation studies and mouse lymphoma tests have demonstrated the safety of HCA-SX. However, no detailed long-term safety of HCA-SX or any other HCA extract has been previously assessed. We evaluated the dose- and time-dependent effects of HCA-SX in Sprague-Dawley rats on body weight, selected organ weights, hepatic lipid peroxidation and DNA fragmentation, hematology and clinical chemistry over a period of 90 days. Furthermore, a 90-day histopathological evaluation was conducted. The animals were treated with 0, 0.2, 2.0 and 5.0% HCA-SX of feed intake and were sacrificed on 30, 60 or 90 days of treatment. The body weight and selected organ weights were assessed and correlated as a % of body weight and brain weight at 90 days of treatment. A significant reduction in body weight was observed in treated rats as compared to control animals. An advancing age-induced marginal increase in hepatic lipid peroxidation was observed in both male and female rats, while no such difference in hepatic DNA fragmentation was observed as compared to the control animals. Furthermore, selected organ weights individually and as a % of body weight and brain weight at 90 days of treatment exhibited no significant difference between the groups. No difference was observed in hematology and clinical chemistry or the histopathological evaluation. Taken together, these results show that 90 day treatment of HCA-SX results in a reduction in body weight, and does not cause any changes in major organs or in hematology, clinical chemistry, and histopathology.

Effect of hydroxycitrate on respiratory quotient, energy expenditure, and glucose tolerance in male rats after a period of restrictive feeding

OBJECTIVE

Recently we demonstrated that hydroxycitrate (HCA) suppresses food intake and body weight regain in male rats after substantial body weight loss. However, it is not known whether HCA also affects the respiration quotient (RQ), energy expenditure (EE), and glucose tolerance in this animal model.

METHODS

Twenty-four male rats (initial body weight, 378 +/- 3 g) were fed restrictively (10 g/d) for 10 d and then given ad libitum access to a high-glucose diet supplemented with 3% HCA for 6 d. Controls received the same diet without the supplement. RQ and EE were measured during ad libitum days 1, 2, and 6. An oral glucose tolerance test was performed on ad libitum day 4 or 5.

RESULTS

HCA decreased RQ and EE during ad libitum days 1 and 2. In all probability, these findings reflect a decrease in de novo lipogenesis. On ad libitum day 6, RQ and EE did not differ between treatment groups. HCA suppressed food intake during the first 3 d ad libitum, but overall body weight regain was not decreased in the HCA group. The oral glucose tolerance test showed that HCA significantly decreased the increase in plasma glucose from baseline (Deltaglucose) and tended to decrease the area under the curve for glucose. Deltainsulin and area under the curve for insulin did not differ between groups.

CONCLUSIONS

These results indicate that, in this animal model, HCA suppresses de novo lipogenesis. Moreover, HCA may improve glucose tolerance.

Safety assessment of (-)-hydroxycitric acid and Super CitriMax, a novel calcium/potassium salt

(-)-Hydroxycitric acid (HCA) is a principle constituent (10-30%) of the dried fruit rind of Garcinia cambogia, a plant native to Southeastern Asia. The dried rind has been used for centuries throughout Southeast Asia as a food preservative, flavoring agent and carminative. Extensive experimental studies show that HCA inhibits fat synthesis and reduces food intake. The objective of this review is to systematically review the available safety/toxicity literature on HCA to determine its safety in-use. The primary mechanism of action of HCA appears to be related to its ability to act as a competitive inhibitor of the enzyme ATP-citrate lyase, which catalyzes the conversion of citrate and coenzyme A to oxaloacetate and acetyl coenzyme A (acetyl-CoA), primary building blocks of fatty acid and cholesterol synthesis. Super CitriMax, a novel calcium/potassium-HCA extract (HCA-SX), is considerably more soluble and bioavailable than calcium-based HCA ingredients. Acute oral toxicity studies in animals demonstrate that CitriMax (50% HCA as calcium salt) has a low acute oral toxicity. In a subchronic study in rats, the gavage administration of HCA-SX at doses up to 2500 mg/kg/day for a period of 90 days caused a significant decrease in body weight and reduction in feed consumption without any adverse effects. The structure, mechanism of action, long history of use of HCA and other toxicity studies indicate that HCA-SX is unlikely to cause reproductive or developmental effects. HCA-SX was not mutagenic in the presence or absence of metabolic activation in Ames genotoxicity assays in strains TA98 and TA102. HCA-SX-induced increases in number of revertants in other strains (TA100 and TA1535 in the absence of metabolic activation and in strain TA1537 in the presence of metabolic activation) but these were not considered as biologically indicative of a mutagenic effect. In several, placebo-controlled, double-blind trials employing up to 2800 mg/day HCA, no treatment-related adverse effects were reported. There is sufficient qualitative and quantitative scientific evidence, including animal and human data suggesting that intake of HCA at levels up to 2800 mg/day is safe for human consumption.

Dose- and time-dependent effects of a novel (-)-hydroxycitric acid extract on body weight, hepatic and testicular lipid peroxidation, DNA fragmentation and histopathological data over a period of 90 days

(-)-Hydroxycitric acid (HCA), a natural extract from the dried fruit rind of Garcinia cambogia (family Guttiferae), is a popular supplement for weight management. The dried fruit rind has been used for centuries as a condiment in Southeastern Asia to make food more filling and satisfying. A significant number of studies highlight the efficacy of Super CitriMax (HCA-SX, a novel 60% calcium-potassium salt of HCA derived from Garcinia cambogia) in weight management. These studies also demonstrate that HCA-SX promotes fat oxidation, inhibits ATP-citrate lyase (a building block for fat synthesis), and lowers the level of leptin in obese subjects. Acute oral, acute dermal, primary dermal irritation and primary eye irritation toxicity studies have demonstrated the safety of HCA-SX. However, no long-term safety of HCA-SX or any other (-)-hydroxycitric acid extract has been previously assessed. In this study, we have evaluated the dose- and time-dependent effects of HCA-SX in Sprague-Dawley rats on body weight, hepatic and testicular lipid peroxidation, DNA fragmentation, liver and testis weight, expressed as such and as a % of body weight and brain weight, and histopathological changes over a period of 90 days. The animals were treated with 0, 0.2, 2.0 and 5.0% HCA-SX as feed intake and the animals were sacrificed on 30, 60 or 90 days of treatment. The feed and water intake were assessed and correlated with the reduction in body weight. HCA-SX supplementation demonstrated a reduction in body weight in both male and female rats over a period of 90 days as compared to the corresponding control animals. An advancing age-induced marginal increase in hepatic lipid peroxidation was observed in both male and female rats as compared to the corresponding control animals. However, no such difference in hepatic DNA fragmentation and testicular lipid peroxidation and DNA fragmentation was observed. Furthermore, liver and testis weight, expressed as such and as a percentage of body weight and brain weight, at 30, 60 and 90 days of treatment, exhibited no significant difference between the four groups. Taken together, these results indicate that treatment of HCA-SX over a period of 90 days results in a reduction in body weight, but did not cause any changes in hepatic and testicular lipid peroxidation, DNA fragmentation, or histopathological changes.

The effect of grape-seed extract on 24 h energy intake in humans

OBJECTIVE

Since grape-seed extract has been shown to stimulate lipolysis in vitro and reduce food intake in rats, we assessed the efficacy of grape-seed extract with respect to energy intake (EI) and satiety.

DESIGN

In a randomized, placebo-controlled, double-blind, cross-over study, 51 subjects (age 18-65 y, body mass index 22-30 kg/m2) ate an ad libitum lunch and dinner twice in the University Restaurant for 3 days. Standard breakfasts and snacks were provided. Supplements were taken 30-60 min prior to each meal.

RESULTS

In the total study population, no difference in 24 h EI was found between the grape-seed extract and placebo. However, in the subgroup of subjects (n=23) with an energy requirement > or =the median of 7.5 MJ/day, EI was reduced by 4% (DeltaEI 352.1 kJ/24 h, P=0.05) after grape-seed extract compared to placebo treatment. Meanwhile, there were no significant differences in macronutrient composition, attitude towards eating, satiety, mood or tolerance.

CONCLUSIONS

Grape seed reduced 24 h EI, with on average 4% in subjects who had an energy requirement > or =7.5 MJ/day, without further effects on satiety, mood or tolerance. These findings suggest that grape seed could be effective in reducing 24 h EI in normal to overweight dietary unrestrained subjects, and could, therefore, play a significant role in body-weight management.

Effect of conjugated linoleic acid supplementation after weight loss on appetite and food intake in overweight subjects

OBJECTIVE

To study the effects of 13 weeks conjugated linoleic acid (CLA) supplementation in overweight subjects on body-weight maintenance, parameters of appetite and energy intake (EI) at breakfast after weight loss.

DESIGN

This study had a double-blind, placebo-controlled randomized design.

SUBJECTS

A total of 26 men and 28 women (age 37.8+/-7.7 y; body mass index 27.8+/-1.5 kg/m(2)).

INTERVENTIONS

Subjects were first submitted to a very-low-calorie diet (VLCD; 2.1 MJ/day) for 3 weeks after which they started with the 13-week intervention period. They either received 1.8 g CLA or placebo per day or 3.6 g CLA or placebo per day. Additionally, subjects of the high dosage intervention replaced their habitual lunch by one meal of a protein-rich, low-energy supplement. EI was measured at breakfast and appetite profile after an overnight fast.

RESULTS

The mean body weight loss was 6.9+/-1.7% of their original body weight. Multiple regression analysis showed that at the end of the 13-week intervention, CLA did not have an effect on body weight regain. Feelings of fullness and satiety were increased and feelings of hunger were decreased after 13 weeks intervention by CLA compared to placebo, independent of %body weight regain. However, EI measured at breakfast was not affected by CLA.

CONCLUSION

Appetite (hunger, satiety and fullness) was favorably, dose-independently affected by a 13-week consumption of 1.8 or 3.6 g CLA/day. This did not result in a lower EI at breakfast or an improved body-weight maintenance after weight loss.

Body weight and abdominal fat gene expression profile in response to a novel hydroxycitric acid-based dietary supplement

Obesity is a global public health problem, with about 315 million people worldwide estimated to fall into the WHO-defined obesity categories. Traditional herbal medicines may have some potential in managing obesity. Botanical dietary supplements often contain complex mixtures of phytochemicals that have additive or synergistic interactions. The dried fruit rind of Garcinia cambogia, also known as Malabar tamarind, is a unique source of (-)-hydroxycitric acid (HCA), which exhibits a distinct sour taste and has been safely used for centuries in Southeastern Asia to make meals more filling. Recently it has been demonstrated that HCA-SX or Super Citrimax, a novel derivative of HCA, is safe when taken orally and that HCA-SX is bioavailable in the human plasma as studied by GC-MS. Although HCA-SX has been observed to be conditionally effective in weight management in experimental animals as well as in humans, its mechanism of action remains to be understood. We sought to determine the effects of low-dose oral HCA-SX on the body weight and abdominal fat gene expression profile of Sprague-Dawley rats. We observed that at doses relevant for human consumption dietary HCA-SX significantly contained body weight growth. This response was associated with lowered abdominal fat leptin expression while plasma leptin levels remained unaffected. Repeated high-density microarray analysis of 9960 genes and ESTs present in the fat tissue identified a small set (approximately 1% of all genes screened) of specific genes sensitive to dietary HCA-SX. Other genes, including vital genes transcribing for mitochondrial/nuclear proteins and which are necessary for fundamental support of the tissue, were not affected by HCA-SX. Under the current experimental conditions, HCA-SX proved to be effective in restricting body weight gain in adult rats. Functional characterization of HCA-SX-sensitive genes revealed that upregulation of genes encoding serotonin receptors represent a distinct effect of dietary HCA-SX supplementation.