Bitter melon (Momordica charantia L.) inhibits adipocyte hypertrophy and down regulates lipogenic gene expression in adipose tissue of diet-induced obese rats

Balancing adipocyte production and lipid metabolism to treat obesity-induced diabetes with a novel proteoglycan from Ganoderma lucidum

Obesity is often accompanied by metabolic disorder and insulin resistance, resulting in type 2 diabetes. Based on previous findings, FYGL, a natural hyperbranched proteoglycan extracted from the G. lucidum fruiting body, can decrease blood glucose and reduce body weight in diabetic mice. In this article, the underlying mechanism of FYGL in ameliorating obesity-induced diabetes was further investigated both in vivo and in vitro. FYGL upregulated expression of metabolic genes related to fatty acid biosynthesis, fatty acid β-oxidation and thermogenesis; downregulated the expression of insulin resistance-related genes; and significantly increased the number of beige adipocytes in db/db mice. In addition, FYGL inhibited preadipocyte differentiation of 3T3-L1 cells by increasing the expression of FABP-4. FYGL not only promoted fatty acid synthesis but also more significantly promoted triglyceride degradation and metabolism by activating the AMPK signalling pathway, therefore preventing fat accumulation, balancing adipocyte production and lipid metabolism, and regulating metabolic disorders and unhealthy obesity. FYGL could be used as a promising pharmacological agent for the treatment of metabolic disorder-related obesity.

Anti-adipogenic activities of pheophorbide a and pyropheophorbide a isolated from wild bitter gourd (Momordica charantia L. var. abbreviata Seringe) in vitro

BACKGROUND

The wild bitter gourd (WBG) is a commonly consumed vegetable in Asia that has antioxidant and hypoglycemic properties. The present study aimed to investigate the anti-adipogenic activities of isolated compounds from WBG on 8-day differentiated cultures of 3 T3-L1 adipocytes that were then stained with Oil Red O (ORO) or diamidino-2-phenylindole (DAPI).

RESULTS

ORO stains of the methanol extracts of de-seeded HM86 cultivar of WBG (WBG-M) and the ethyl acetate fractions (WBG-M-EA) showed anti-adipogenic activities against differentiated adipocytes. Two chlorophyll-degraded compounds, pheophorbide a (1) and pyropheophorbide a (2), were isolated from WBG-M-EA. Treatments with 1 (5, 10, and 20 μmol L^-1 ) and 2 (2.5, 5, and 10 μmol L^-1 ) showed dose-dependent reductions in lipid accumulations and reduced nuclear DAPI stains in differentiated 3 T3-L1 adipocytes. The concentrations for 50% inhibition against lipid accumulations of 1 and 2, respectively, were 16.05 and 7.04 μmol L^-1 . Treatments with 1 and 2 showed enhanced lactate dehydrogenase release in the first 4-day cell mitotic clonal expansions during the differentiating cultural processes, although the effect was less on the non-differentiating cultural processes. Thus, 1 and 2 were more toxic to differentiating adipocytes than to non-differentiated pre-adipocytes, which partly resulted in anti-adipogenic activities with lowered lipid accumulations.

CONCLUSION

Both 1 and 2 showed anti-adipogenic activities in cell models. These chlorophyll-degraded compounds commonly exist in several vegetables during storage or edible seaweeds, which will provide resources for further investigations aiming to test anti-obesity in animal studies. © 2022 Society of Chemical Industry.

Effect of Momordica charantia Administration on Anthropometric Measures and Metabolic Profile in Patients with Obesity: A Pilot Clinical Trial

The aim of this study was to evaluate the effect of Momordica charantia (MC) administration on anthropometric measures in patients with obesity. A randomized, double-blind, placebo-controlled pilot clinical trial was carried out in 24 patients with obesity. Twelve patients randomly received MC (2000 mg/day) for 12 weeks, and 12 patients received placebo. Body weight (BW), body mass index (BMI), waist circumference (WC), body fat percentage, as well as clinical and laboratory determinations, were evaluated before and after the intervention. Results showed that while reductions in BW, BMI, WC, and body fat percentage were observed in the MC group, these differences did not reach statistical significance. Significant decreases in triglycerides (TG) (1.9 ± 0.6 mM vs. 1.7 ± 0.7 mM, P ≤ .05) and very low-density lipoprotein (VLDL) (0.4 ± 0.1 mM vs. 0.3 ± 0.1 mM, P ≤ .05) levels were found after the intervention with MC. In contrast, significant increases in BW (83.0 ± 10.7 kg vs. 84.6 ± 9.1 kg, P ≤ .05) and BMI (31.9 ± 1.5 kg/m² vs. 33.0 ± 1.3 kg/m², P ≤ .05) were observed in the placebo group. In conclusion, no significant reductions in BW, BMI, WC, and body fat percentage were observed after MC administration; however, MC significantly decreased TG and VLDL levels. The protocol was registered at ClinicalTrials.gov with the identifier NCT04916379.

The Multifunctional Role of Herbal Products in the Management of Diabetes and Obesity: A Comprehensive Review

Obesity and diabetes are the most demanding health problems today, and their prevalence, as well as comorbidities, is on the rise all over the world. As time goes on, both are becoming big issues that have a big impact on people’s lives. Diabetes is a metabolic and endocrine illness set apart by hyperglycemia and glucose narrow-mindedness because of insulin opposition. Heftiness is a typical, complex, and developing overall wellbeing worry that has for quite some time been connected to significant medical issues in individuals, all things considered. Because of the wide variety and low adverse effects, herbal products are an important hotspot for drug development. Synthetic compounds are not structurally diverse and lack drug-likeness properties. Thus, it is basic to keep on exploring herbal products as possible wellsprings of novel drugs. We conducted this review of the literature by searching Scopus, Science Direct, Elsevier, PubMed, and Web of Science databases. From 1990 until October 2021, research reports, review articles, and original research articles in English are presented. It provides top to bottom data and an examination of plant-inferred compounds that might be utilized against heftiness or potentially hostile to diabetes treatments. Our expanded comprehension of the systems of activity of phytogenic compounds, as an extra examination, could prompt the advancement of remedial methodologies for metabolic diseases. In clinical trials, a huge number of these food kinds or restorative plants, as well as their bioactive compounds, have been shown to be beneficial in the treatment of obesity.

Cucurbitane-type triterpenoids from the vines of Momordica charantia and their anti-inflammatory, cytotoxic, and antidiabetic activity

Phytochemical investigation of the ethanol extract from wild Momordica charantia vines has resulted in isolation of seven cucurbitane-type triterpenoids, including six undescribed compounds, kuguaovins H‒M, and the known compound, momordicoside K. The structures of the isolated compounds were elucidated on the basis of spectroscopic analyses, including 1D and 2D NMR, and MS experiments. The chemical structure of momordicoside K was determined for the first time by X-ray crystallographic analysis and its absolute configuration assigned. The cytotoxicity against four human tumor cell lines and anti-inflammatory activities on LPS-stimulated RAW264.7 macrophages were evaluated. Of the isolates, kaguaovin L exhibited potential cytotoxicity against MCF-7, HEp-2, Hep-G2, and WiDr cancer cell lines and showed moderate anti-NO production activity. In addition, kuguaovins H and J also showed the stimulatory effect of GLP-1 secretion on the murine intestinal secretin tumor cell line (STC-1).

Adipose and non-adipose perspectives of plant derived natural compounds for mitigation of obesity

ETHNOPHARMACOLOGICAL RELEVANCE

Phyto-preparations and phyto-compounds, by their natural origin, easy availability, cost-effectiveness, and fruitful traditional uses based on accumulated experiences, have been extensively explored to mitigate the global burden of obesity.

AIM OF THIS REVIEW

The review aimed to analyse and critically summarize the prospect of future anti-obesity drug leads from the extant array of phytochemicals for mitigation of obesity, using adipose related targets (adipocyte formation, lipid metabolism, and thermogenesis) and non-adipose targets (hepatic lipid metabolism, appetite, satiety, and pancreatic lipase activity). Phytochemicals as inhibitors of adipocyte differentiation, modulators of lipid metabolism, and thermogenic activators of adipocytes are specifically discussed with their non-adipose anti-obesogenic targets.

MATERIALS AND METHODS

PubMed, Google Scholar, Scopus, and SciFinder were accessed to collect data on traditional medicinal plants, compounds derived from plants, their reported anti-obesity mechanisms, and therapeutic targets. The taxonomically accepted name of each plant in this review has been vetted from "The Plant List" (www.theplantlist.org) or MPNS (http://mpns.kew.org).

RESULTS

Available knowledge of a large number of phytochemicals, across a range of adipose and non-adipose targets, has been critically analysed and delineated by graphical and tabular depictions, towards mitigation of obesity. Neuro-endocrinal modulation in non-adipose targets brought into sharp dual focus, both non-adipose and adipose targets as the future of anti-obesity research. Numerous phytochemicals (Berberine, Xanthohumol, Ursolic acid, Guggulsterone, Tannic acid, etc.) have been found to be effectively reducing weight through lowered adipocyte formation, increased lipolysis, decreased lipogenesis, and enhanced thermogenesis. They have been affirmed as potential anti-obesity drugs of future because of their effectiveness yet having no threat to adipose or systemic insulin sensitivity.

CONCLUSION

Due to high molecular diversity and a greater ratio of benefit to risk, plant derived compounds hold high therapeutic potential to tackle obesity and associated risks. This review has been able to generate fresh perspectives on the anti-diabetic/anti-hyperglycemic/anti-obesity effect of phytochemicals. It has also brought into the focus that many phytochemicals demonstrating in vitro anti-obesogenic effects are yet to undergo in vivo investigation which could lead to potential phyto-molecules for dedicated anti-obesity action.

Three Selected Edible Crops of the Genus Momordica as Potential Sources of Phytochemicals: Biochemical, Nutritional, and Medicinal Values

Momordica species (Family Cucurbitaceae) are cultivated throughout the world for their edible fruits, leaves, shoots and seeds. Among the species of the genus Momordica, there are three selected species that are used as vegetable, and for medicinal purposes, Momordica charantia L (Bitter melon), Momordica foetida Schumach (Bitter cucumber) and Momordica balsamina L (African pumpkin). The fruits and leaves of these Momordica species are rich in primary and secondary metabolites such as proteins, fibers, minerals (calcium, iron, magnesium, zinc), β-carotene, foliate, ascorbic acid, among others. The extracts from Momordica species are used for the treatment of a variety of diseases and ailments in traditional medicine. Momordica species extracts are reputed to possess anti-diabetic, anti-microbial, anthelmintic bioactivity, abortifacient, anti-bacterial, anti-viral, and play chemo-preventive functions. In this review we summarize the biochemical, nutritional, and medicinal values of three Momordica species (M. charantia, M. foetida and M. balsamina) as promising and innovative sources of natural bioactive compounds for future pharmaceutical usage.

Bitter Melon (Momordica charantia L.) Fruit Bioactives Charantin and Vicine Potential for Diabetes Prophylaxis and Treatment

Natural products are gaining clinical significance in modern day health care systems to prevent diseases. Bitter melon, a health promoting vegetable, is traditionally used for medical nutrition therapy to cure diabetes but to reap maximum health claims, vigilant control of its substances in diet is crucial as part of curative action for effective diabetes management. In the present research, first phase focused on detection of key bioactive components, i.e., charantin and vicine in different parts of its fruit. In the second phase, normal and hyperglycemic Sprague Dawley rats were fed on skin, flesh and whole fruit of bitter melon at 150 and 300 mg/kg body weight and assessed for diabetes prophylaxis and treatment. The highest amount of charantin (0.16 ± 0.02 mg/g) was recorded in flesh while vicine was present in abundance in whole fruit (0.21 ± 0.01 μg/100 g). In normal rats, bitter melon supplementation was helpful in managing the onset of diabetes. Hyperglycemic rats showed diabetic complications including polydipsia, polyuria, glycosuria, renal hypertrophy and increased glomerular filtration rate. However, bitter melon consumption showed significant improvements in these parameters. The most potent dose was 300 mg/kg whole fruit that resulted in 31.64% lowering of blood glucose level and 27.35% increase in insulin level in hyperglycemic rats.

Momordica Charantia: A Review of Its Effects on Metabolic Diseases and Mechanisms of Action

The global rise in the prevalence of metabolic diseases such as diabetes, obesity, and dyslipidemia is a serious public health issue. The search for safe and effective complementary and alternative therapies to treat metabolic disorders is a key field of research. Momordica charantia (MC) is a tropical and subtropical vine of the Cucurbitaceae family used as a medicinal plant since ancient times. Although MC has been widely studied for its hypoglycemic potential, hypolipidemic and antiobesity effects have also been reported in preclinical studies and clinical trials. This study aims to review the metabolic effects of MC reported in clinical trials as well as its mechanisms of action.

Bitter Melon (Momordica charantia L.) Supplementation Has No Effect on Hypercholesterolemia and Atherosclerosis in Mice

Bitter melon (BM; Momordica charantia L.) has been reported to ameliorate diet-induced obesity and dyslipidemia. However, the effects of BM on atherosclerosis have not been determined. This study investigated the effects of BM diet-induced atherosclerosis in LDL receptor-deficient mice. A total of 30 female mice (aged 6-8 wk) were fed a saturated fat-enriched diet. In group 1 (n = 10), mice were fed this diet alone, whereas mice in groups 2 and 3 (n = 10/group) were fed the diet supplemented with BM either 0.1% or 1% by weight. After 12 wk, body weight, plasma cholesterol, and atherosclerotic plaque areas were analyzed. No significant differences in body weight and plasma cholesterol concentrations were observed among the groups. Also, BM supplementation did not affect atherosclerosis development. In conclusion, dietary BM has no effect on plasma cholesterol concentration and atherogenesis in hypercholesterolemic mice.

The gut microbiota confers the lipid-lowering effect of bitter melon (Momordica charantia L.) In high-fat diet (HFD)-Induced hyperlipidemic mice

The bitter melon (Momordica charantia) is a medical food with well-documented hypoglycemic and anti-hyperlipidemic activities. Previous studies showed that the M. charantia fruit (MC) could modulate the gut microbiota, but whether this modulation is essential for MC's pharmacological effects is largely unknown. Here, we assessed the causality of gut microbes in MC-elicited anti-hyperlipidemic effects for the first time. Oral administration of MC significantly prevented hyperlipidemia, but this amelioration substantially diminished when co-treated with antibiotics. Transplantation of gut flora from MC-treated donor mice also significantly decreased serum lipids. The microbiological analysis revealed that MC moderately increased diversity and shifted the overall structure of gut microbiota. It selectively enhanced the relative abundance of short-chain fatty acid (SCFAs)-producing genera and increased fecal SCFAs content. These results demonstrate that M. charantia fruit (MC) may exert an anti-hyperlipidemic effect through modulating gut microbes and increasing SCFAs production.

Extra-oral bitter taste receptors: New targets against obesity?

Taste perception on the tongue is essential to help us to identify nutritious or potential toxic food substances. Emerging evidence has demonstrated the expression and function of bitter taste receptors (TAS2Rs) in a wide range of extra-oral tissues. In particular, TAS2Rs in gastrointestinal enteroendocrine cells control the secretion of appetite regulating gut hormones and influence hunger and food intake. Furthermore, these effects may be reinforced by the presence of TAS2Rs on intestinal smooth muscle cells, adipocytes and the brain. This review summarises how activation of extra-oral TAS2Rs can influence appetite and body weight control and how obesity impacts the expression and function of TAS2Rs. Region-selective targeting of bitter taste receptors may be promising targets for the treatment of obesity.

Susceptibility of poultry associated bacterial pathogens to Momordica charantia fruits and evaluation of in vitro biological properties

The emerging incidence of antibiotic resistance trait among the bacteria populating poultry presents a devastating public health issue. On the other hand, at present, diabetes and obesity are the most serious public health issues and are increasing subsequently at alarming rate. In view of this, the present in vitro context was aimed to investigate the antibacterial activities of Momordica charantia (M. charantia) fruits extracts against poultry associated Bacillus spp. and to assess further its phytoconstituents, alpha-(α)-glucosidase activities, and anti-obesity properties. The anti-pathogenic attributes of M. charantia fruit extracts were carried out using disc diffusion assay and results showed the pronounced antibacterial trait of ethanolic extract with maximum zone of inhibition of 28.3 ± 1.2 mm against Bacillus licheniformis. The qualitative phytochemical analyses of fruit extracts illustrated the presence of diverse phytoconstituents. The α-glucosidase inhibition assay for the extracts was performed according to the α-glucosidase activity kit. The results depicted the lowest α-glucosidase activity (57.13 ± 2.3 to 18.14 ± 1.3 U/L) in the presence of ethanolic extract at varied concentrations. The anti-obesity potentialities of fruit extracts were demonstrated in terms of porcine pancreatic lipase (PPL type II) activity using p-nitro-phenyl butyrate (p-NPB) as a substrate. The ethanolic extract of M. charantia fruits was observed to exhibit maximum inhibition of pancreatic lipase ranging from 20.12 ± 2.3 to 68.34 ± 1.3% in a dose dependent manner with an IC₅₀ value of 607.6 ± 1.3 μg/mL. FTIR and GC-MS results indicated the presence of distinct compounds in the ethanol extract and major bioactive constituents were found to be Dimethyl sulfone (35.24%), 9-octadecanamide (20.52%), Pentadecanoic acid (6.64%), Lanost-9 (11)-en-18-oic acid, 23-(acetylxyl)-3-(4-bromobenzoyl) oxyl-20-hydroxyl-gamma-lactone (2.6%), and 2,2-sulfonyldiethanol (2.46%). In conclusion, M. charantia fruits could be of great concern in pharmaceutical industries due to its adequate biological properties and may also help in the management of poultry associated bacterial pathogens.

Association of Vegetable, Fruit, and Okinawan Vegetable Consumption With Incident Stroke and Coronary Heart Disease

Background

Few studies have investigated the effects of Okinawan vegetable consumption on the risk of incident stroke and coronary heart disease. This study aimed to examine associations of vegetable, fruit, and Okinawan vegetable consumption with risk of incident stroke and coronary heart disease in the Japanese population of Okinawa.

Methods

The study design was a prospective cohort study. During 1995–1998, a validated food frequency questionnaire was administered in two study areas to 16,498 participants aged 45–74 years. In 217,467 person-years of follow-up until the end of 2012, a total of 839 stroke cases and 197 coronary heart disease cases were identified.

Results

No statistically significant association between total Okinawan vegetable consumption and risk of stroke and coronary heart disease was obtained: the multivariable adjusted hazard ratios for the highest versus lowest tertile of consumption were 1.09 (95% confidence interval, 0.93–1.29; P for trend = 0.289) in model 2. Total vegetable and fruit and specific Okinawan vegetable consumption were also not statistically significantly associated with risk of cardiovascular outcomes.

Conclusions

This study demonstrated that consumption of total vegetable and fruit, total Okinawan vegetables, and specific Okinawan vegetables in Japanese residents of Okinawa was not associated with risk of incident stroke and coronary heart disease.

Bitter Melon (Momordica charantia L) Fruit Decreased Blood Glucose Level and Improved Lipid Profile of Streptozotocin Induced Hyperglycemia Rats

Bitter melon (Momordica charantia, L) is a fruit that traditionally believe has benefits on health. The objective of this study is to identify bitter melon bioactive and nutritional compounds, and their effect on blood glucose level and lipid profile of streptozotocin induced hyperglycemia rats. Rats were divided into three group, those were normal group; hyperglycemia group without bitter melon fruit feeding; and hyperglycemia group with bitter melon fruit administration. Hyperglycemia condition was achieved by STZ induction. The experiment was conducted for 4 weeks. The results showed that fresh bitter melon fruit contains β-sitosterol 348.16+1.66 ppm, stigmasterol 183.08+0.8 ppm, campesterol 130.79+0.4 ppm, diosgenin 16.42+0.06 ppm, soluble dietary fiber 2.99+0.07%, insoluble dietary fiber 0.55+0.01%, and pectin 1.41+0.05%. At week 4 of experiment, bitter melon fruit fed hyperglycemia group showed a decrease of 56% blood glucose level compared to blood glucose level at week 0. Body weight of this group also increased. The improvement of lipid profile of bitter melon fed group was indicated by decreasing blood total cholesterol of 49%, triglyceride of 35%, LDL cholesterol of 42%, and increasing HDL of 133% compared to initial level at week 0. Bitter melon also increased fecal cholesterol secretion and effectively inhibited cholesterol absorption in hyperglycemia rats. Bitter melon fruit is suggested for hyperglycemia management due to its ability to reduce glucose and improve lipid profile simultaneously.

Bitter gourd reduces elevated fasting plasma glucose levels in an intervention study among prediabetics in Tanzania

ETHNOPHARMACOLOGICAL RELEVANCE

Impaired glucose tolerance and diabetes mellitus have become major health issues even in non-industrialized countries. As access to clinical management is often poor, dietary interventions and alternative medicines are required. For bitter gourd, Momordica charantia L., antidiabetic properties have been claimed.

AIM OF THE STUDY

The main objective of the intervention study was to assess antidiabetic effects of daily bitter gourd consumption of 2.5g powder over the course of eight weeks among prediabetic individuals.

MATERIALS AND METHODS

In a randomized placebo-controlled single blinded clinical trial, 52 individuals with prediabetes were studied after consuming a bitter gourd or a cucumber juice. For reducing the impact of between subject differences in the study population, a crossover design was chosen with eight weeks for each study period and four weeks washout in between. Fasting plasma glucose was chosen as the primary outcome variable.

RESULTS

Comparing the different exposures, the CROS analysis (t=-2.23, p=0.031, r=0.326) revealed a significant difference in the change of FPG of 0.31mmol/L (5.6mg/dL) with a trend (R²=0,42387). The number of 44 finally complete data sets achieved a power of 0.82, with a medium-to-large effect size (Cohen's d 0.62). The effect was also proven by a general linear mixed model (estimate 0.31; SE: 0.12; p: 0.01; 95%CI: 0.08; 0.54). Not all participants responded, but the higher the initial blood glucose levels were, the more pronounced the effect was. No serious adverse effects were observed.

CONCLUSIONS

Bitter gourd supplementation appeared to have benefits in lowering elevated fasting plasma glucose in prediabetes. The findings should be replicated in other intervention studies to further investigate glucose lowering effects and the opportunity to use bitter gourd for dietary self-management, especially in places where access to professional medical care is not easily assured.

Phytotherapy in the Management of Diabetes: A Review

Phytotherapy has long been a source of medicinal products and over the years there have been many attempts to use herbal medicines for the treatment of diabetes. Several medicinal plants and their preparations have been demonstrated to act at key points of glucidic metabolism. The most common mechanisms of action found include the inhibition of α-glucosidase and of AGE formation, the increase of GLUT-4 and PPARs expression and antioxidant activity. Despite the large amount of literature available, the actual clinical effectiveness of medicinal plants in controlling diabetes-related symptoms remains controversial and there is a crucial need for stronger evidence-based data. In this review, an overview of the medicinal plants, which use in the management of diabetes is supported by authoritative monographs, is provided. References to some species which are currently under increasing clinical investigation are also reported.

Anti-obesity effect of robusta fermented with Leuconostoc mesenteroides in high-fat diet-induced obese mice

Robusta beans cultivated with Monascus ruber (RMR) were successively fermented with Leuconostoc mesenteroides (LM) and the antiobesity effects were examined. To produce an obese mouse model to investigate the hypolipidemic effects, ICR mice were fed the same high-fat diet for 6 weeks. Treatment groups were given 10 or 20% RMR-LM. Body weight changes in the 20% RMR-LM group were lower compared with those in the control group. Visceral adipose tissue weight and adipose size were significantly lower in the 20% RMR-LM group compared with those in the control group. Significant improvement in glucose tolerance was observed in the 10 and 20% RMR-LM groups compared with the control group. The 20% RMR-LM group exhibited a significant reduction in serum glucose concentration. Hepatic mRNA levels of sterol regulatory element-binding protein 1, fas cell surface death receptor, and peroxisome proliferator-activated receptor γ, which are associated with lipid, and fatty acid metabolism, in the 20% RMR-LM group were significantly lower compared with those in the control group. The results of the present study demonstrated that 20% RMR-LM may be used to prevent obesity, and ameliorate diabetes and lipid metabolism imbalances.

Effects of Karela (Bitter Melon; Momordica charantia) on genes of lipids and carbohydrates metabolism in experimental hypercholesterolemia: biochemical, molecular and histopathological study

Background

Hypercholesterolemia is a serious diseases associated with type-2 diabetes, atherosclerosis, cardiovascular disorders and liver diseases. Humans seek for safe herbal medication such as karela (Momordica charantia/bitter melon) to treat such disorders to avoid side effect of pharmacotherapies widely used.

Methods

Forty male Wistar rats were divided into four equal groups; control group with free access to food and water, cholesterol administered group (40 mg/kg BW orally); karela administered group (5 g /kg BW orally) and mixture of cholesterol and karela. The treatments continued for 10 weeks. Karela was given for hypercholesterolemic rats after 6 weeks of cholesterol administration. Serum, liver and epididymal adipose tissues were taken for biochemical, histopathological and genetic assessments.

Results

Hypercholesterolemia induced a decrease in serum superoxide dismutase (SOD), catalase, reduced glutathione (GSH) and an increase in malondialdehyde (MDA) levels that were ameliorated by karela administration. Hypercholesterolemia up regulated antioxidants mRNA expression and altered the expression of carbohydrate metabolism genes. In parallel, hypercholesterolemic groups showed significant changes in the expression of PPAR-alpha and gamma, lipolysis, lipogenesis and cholesterol metabolism such as carnitine palmitoyltransferase-1 (CPT-1). Acyl CoA oxidase (ACO), fatty acids synthase (FAS), sterol responsible element binding protein-1c (SREBP1c), 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoAR) and cholesterol 7α-hydroxylase (CYP7A1) at hepatic and adipose tissue levels. Interestingly, Karela ameliorated all altered genes confirming its hypocholesterolemic effect. Histopathological and immunohistochemical findings revealed that hypercholesterolemia induced hepatic tissue changes compared with control. These changes include cholesterol clefts, necrosis, karyolysis and sever congestion of portal blood vessel. Caspase-3 immunoreactivity showed positive expression in hepatic cells of hypercholesterolemic rats compared to control. All were counteracted and normalized after Karela administration to hypercholesterolemic group.

Conclusion

Current findings confirmed that karela is a potential supplement useful in treatment of hypercholesterolemia and its associated disorders and is good for human health.

Bitter melon protects against ER stress in LS174T colonic epithelial cells

BACKGROUND

Bitter Melon (BM) has been used as a functional food in traditional Chinese and Indian medicine for many generations and has gained a great deal of attention due to its apparent benefits in moderating some of the pathogenic processes in a variety of inflammatory conditions. BM extract (BME) has been shown to possess strong anti-oxidant properties. In addition, it can ameliorate oxidative stress and potentially ER stress. There is increasing evidence that oxidative and ER stress are major contributors for intestinal secretory cell dysfunction which leads to local inflammation and disease pathogenesis that are hallmarks of inflammatory bowel diseases (IBD). Hence, the search for potential therapeutics against ER stress and oxidative stress in intestinal epithelial secretory cells may provide valuable resources for the management of IBD. The aim of the present study was to investigate the effects of BME in ameliorating ER stress in colonic epithelial cells.

METHODS

Human colonic adenocarcinoma LS174T cells were used for the assessment of BME effects on colonic epithelial cells in vitro. Cell viability was assessed using trypan blue exclusion and the effect of BME in ameliorating tunicamycin (TM)-induced ER stress was determined by analysing the mRNA expression of the common ER stress markers; ATF6, XBP1, GRP78, CHOP and PERK by quantitative RT-PCR and GRP78 and CHOP by western blot.

RESULTS

In the absence of ER stress, BME exhibited no cell toxicity up to 2.0% w/v and no significant effect on the basal mRNA expression of ER stress markers in LS174T cells. In contrast, pre-treatment of LS174T cells with BME followed by induction of ER stress resulted in a significant decrease in mRNA expression of ATF6, XBP1, GRP78, CHOP and PERK and protein expression of GRP78 and CHOP. Co-treatment during induction of ER stress and post- treatment following induction of ER Stress in LS174T cells resulted in a lower but still significant reduction in mRNA expression levels of most ER stress markers.

CONCLUSIONS

This is one of the first studies demonstrating the efficacy of BME in reducing expression of ER stress markers in colonic epithelial cells suggesting the potential of BME as a dietary intervention in ameliorating ER stress and oxidation in IBD. Interestingly, while the most significant effect was seen with pre-treatment of cells with BME there was a reduced but still significant effect when co-treated or even post-treated. This suggests that BME may even be effective in modulating ER stress in the face of an existing cell stress environment.

Response of gut microbiota and inflammatory status to bitter melon (Momordica charantia L.) in high fat diet induced obese rats

ETHNOPHARMACOLOGICAL RELEVANCE

Bitter melon (Momordica charantia L.) is rich in a variety of biologically active ingredients, and has been widely used in traditional Chinese medicine (TCM) to treat various diseases, including type 2 diabetes and obesity.

AIM OF THE STUDY

We aimed to investigate how bitter melon powder (BMP) could affect obesity-associated inflammatory responses to ameliorate high-fat diet (HFD)-induced insulin resistance, and investigated whether its anti-inflammatory properties were effected by modulating the gut microbiota.

MATERIALS AND METHODS

Obese SD rats (Sprague-Dawley rats, rattus norregicus) were randomly divided into four groups: (a) normal control diet (NCD) and distilled water, (b) HFD and distilled water, (c) HFD and 300mg BMP/kg body weight (bw), (d) HFD and 10mg pioglitazone (PGT)/kg bw.

RESULTS

We observed remarkable decreases in the fasting glucose, fasting insulin, HOMA-IR index, serum lipid levels, and cell sizes of epididymal adipose tissues in the BMP and PGT groups after 8 weeks. BMP could significantly improve the proinflammatory cytokine tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), anti-inflammatory cytokine interleukin-10 (IL-10), and local endotoxin levels compared to the HFD group (p<0.05). BMP suppressed the activation of nuclear factor-κB (NF-κB) by inhibiting inhibitor of NF-κB alpha (IκBα) degradation and phosphorylation of c-Jun N-terminal kinase/ p38 mitogen-activated protein kinases (JNK/p38 MAPKs) in adipose tissue. Sequencing results illustrated that BMP treatment markedly decreased the proportion of the endotoxin-producing opportunistic pathogens and increased butyrate producers.

CONCLUSIONS

These results demonstrate that BMP ameliorates insulin sensitivity partly via relieving the inflammatory status in the system and in white adipose tissues of obese rats, and is associated with a proportional regulation of specific gut microbiota.

1H NMR-based metabolic study reveals the improvements of bitter melon (Momordica charantia) on energy metabolism in diet-induced obese mouse

CONTEXT

Obesity can be ameliorated by some natural products such as polyphenol, flavones and saponin. As a typical medicinal plant, Momordica charantia L. (Cucurbitaceae) (bitter melon, BM) contains these natural chemicals and reduces diet-induced obesity in mice.

OBJECTIVE

This study evaluates the metabolic effects of dietary BM supplement, investigates a global metabolic profile and determines associated perturbations in metabolic pathways.

MATERIALS AND METHODS

Male C57BL/6 mice were fed with low-fat diet (LFD), high-fat diet (HFD) and HFD supplemented with 5% BM based on 37.6 g/kg body weight in average for 12 weeks, respectively. Then energy metabolism was quantified using PhenoMaster/LabMaster. The spectroscopy of urine was acquired by nuclear magnetic resonance and latent biomarkers were identified. Pattern recognition analysis was used to discriminate associated metabolic profiles.

RESULTS

Dietary BM supplement reduced body weight gain (-0.15-fold, p < 0.01) and blood glucose levels (-0.19-fold, p < 0.01) in HFD-fed mice. Meanwhile, the levels of energy metabolism were enhanced (0.08-0.11-fold, p < 0.01). According to pattern recognition analysis, dietary BM supplement changed metabolic profiles in HFD-fed mice and the modified profiles were similar to those in LFD-fed mice. Finally, the mapping of metabolic pathways showed that dietary BM supplement primarily affected glucose metabolism-associated pathways.

DISCUSSION AND CONCLUSION

The results indicated that BM improves weight loss in diet-induced obesity and elevate energy expenditure in HFD-fed mice. The pattern recognition with metabolic study may be used as a noninvasive detection method to assess the effects of dietary BM supplement on mouse energy metabolism.

Evaluation of Protein Kinase Cβ and PPARγ Activity in Diabetic Rats Supplemented with Momordica charantia

INTRODUCTION

The present study was taken up to compare and evaluate the effect of Momordica charantia supplementation with pioglitazone on PKC-β and PPAR-γ activity in kidneys of diabetic rats. The hypoglycaemic and lipid lowering effect of Momordica charantia were screened in laboratory animal model and its potency was compared with a Thiazolidinedione (TZD) group antidiabetic drug like pioglitazone.

MATERIALS AND METHODS

Adult healthy albino rats of Wistar strain aged 3-4months, weighing between 170-250gm of either sex were divided into 4 groups; Group 1 (normal controls), Group 2 (diabetic controls), Group 3 (diabetic rats treated with pioglitazone) and Group 4 (diabetic rats treated with bitter melon juice). Type 1 Diabetes was induced in rats by intraperitoneal injection of streptozotocin at a dose of 55 mg/kg body weight, following which glucose levels were estimated by Accu chek- active glucometer on day 0, 7, 14, 21 and 28 days to assess the efficacy of Bitter Melon Juice (BMJ) and pioglitazone. After 28 days of treatment, the rats were sacrificed and blood collected from abdominal vena cava was used for estimation of triglycerides by Glycerol 3 phosphate oxidase phenol aminophenazone method and cholesterol by Cholestrol oxidase phenol aminophenazone method. PKC-β and PPAR-γ were estimated in the dissected kidneys by using double sandwich ELISA based kits on an automated plate reader.

RESULTS

BMJ significantly reduced blood glucose levels in group 4 as compared to diabetic controls (p<0.001). Total cholesterol and triglycerides were significantly reduced in both group 3 and 4. In Group 4, there was reduction in PKC-β levels, when compared to Group 3(p=0.004). PPAR-γ levels were increased in both Group 3 and 4, when compared to Group 2.

CONCLUSION

The results suggest that BMJ has hypoglycaemic and lipid lowering effect in diabetic animal models. BMJ increases PPAR-γ activity and decreases PKC-β activity in kidneys of diabetic rats, thereby preventing the complications of diabetes mellitus. Fresh BMJ mimics action of pioglitazone belonging to TZD group thus showing a potential for further research in identifying the active molecules responsible for glucose and lipid lowering action.

Beneficial role of bitter melon supplementation in obesity and related complications in metabolic syndrome

Diabetes, obesity, and metabolic syndrome are becoming epidemic both in developed and developing countries in recent years. Complementary and alternative medicines have been used since ancient era for the treatment of diabetes and cardiovascular diseases. Bitter melon is widely used as vegetables in daily food in Bangladesh and several other countries in Asia. The fruits extract of bitter melon showed strong antioxidant and hypoglycemic activities in experimental condition both in vivo and in vitro. Recent scientific evaluation of this plant extracts also showed potential therapeutic benefit in diabetes and obesity related metabolic dysfunction in experimental animals and clinical studies. These beneficial effects are mediated probably by inducing lipid and fat metabolizing gene expression and increasing the function of AMPK and PPARs, and so forth. This review will thus focus on the recent findings on beneficial effect of Momordica charantia extracts on metabolic syndrome and discuss its potential mechanism of actions.

Therapeutic phytogenic compounds for obesity and diabetes

Natural compounds have been used to develop drugs for many decades. Vast diversities and minimum side effects make natural compounds a good source for drug development. However, the composition and concentrations of natural compounds can vary. Despite this inconsistency, half of the Food and Drug Administration (FDA)-approved pharmaceuticals are natural compounds or their derivatives. Therefore, it is essential to continuously investigate natural compounds as sources of new pharmaceuticals. This review provides comprehensive information and analysis on natural compounds from plants (phytogenic compounds) that may serve as anti-obesity and/or anti-diabetes therapeutics. Our growing understanding and further exploration of the mechanisms of action of the phytogenic compounds may afford opportunities for development of therapeutic interventions in metabolic diseases.

Effect of Achyranthes bidentata Blume on 3T3-L1 Adipogenesis and Rats Fed with a High-Fat Diet

The present study investigated the antiobesity effect of Achyranthes bidentata Blume root water extract in a 3T3-L1 adipocyte differentiation model and rats fed with a high-fat diet. To investigate the effect of Achyranthes bidentata Blume on adipogenesis in vitro, differentiating 3T3-L1 cells in adipocyte-induction media were treated every two days with Achyranthes bidentata Blume at various concentrations (1 to 25 μg/mL) for eight days. We found that Achyranthes bidentata Blume root inhibited 3T3-L1 adipocyte differentiation without affecting cell viability, and Western blot analysis revealed that phospho-Akt expression was markedly decreased, whereas there was no significant change in perilipin expression. Furthermore, administration of Achyranthes bidentata Blume root (0.5 g/kg body weight for six weeks) to rats fed with a high-fat diet significantly reduced body weight gain without affecting food intake, and the level of triglyceride was significantly decreased when compared to those in rats fed with only a high-fat diet. These results suggest that Achyranthes bidentata Blume root water extract could have a beneficial effect on inhibition of adipogenesis and controlling body weight in rats fed with a high-fat diet.

Momordica charantia (Bitter Melon) reduces obesity-associated macrophage and mast cell infiltration as well as inflammatory cytokine expression in adipose tissues

Obesity is a world-wide epidemic disease that correlates closely with type 2 diabetes and cardiovascular diseases. Obesity-induced chronic adipose tissue inflammation is now considered as a critical contributor to the above complications. Momordica charantia (bitter melon, BM) is a traditional Chinese food and well known for its function of reducing body weight gain and insulin resistance. However, it is unclear whether BM could alleviate adipose tissue inflammation caused by obesity. In this study, C57BL/6 mice were fed high fat diet (HFD) with or without BM for 12 weeks. BM-contained diets ameliorated HFD-induced obesity and insulin resistance. Histological and real-time PCR analysis demonstrated BM not only reduced macrophage infiltration into epididymal adipose tissues (EAT) and brown adipose tissues (BAT). Flow cytometry show that BM could modify the M1/M2 phenotype ratio of macrophages in EAT. Further study showed that BM lowered mast cell recruitments in EAT, and depressed pro-inflammatory cytokine monocyte chemotactic protein-1 (MCP-1) expression in EAT and BAT as well as interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) expression in EAT. Finally, ELISA analysis showed BM-contained diets also normalized serum levels of the cytokines. In summary, in concert with ameliorated insulin resistance and fat deposition, BM reduced adipose tissue inflammation in diet-induced obese (DIO) mice.

Altered white adipose tissue protein profile in C57BL/6J mice displaying delipidative, inflammatory, and browning characteristics after bitter melon seed oil treatment

Objective

We have previously shown that bitter melon seed oil (BMSO), which is rich in cis-9, trans-11, trans-13 conjugated linolenic acid, is more potent than soybean oil in attenuating body fat deposition in high-fat diet-induced obese C57BL/6J mice. The aim of this study was to obtain a comprehensive insight into how white adipose tissue (WAT) is affected by BMSO administration and to explore the underlying mechanisms of the anti-adiposity effect of BMSO.

Methods and Results

A proteomic approach was used to identify proteins differentially expressed in the WAT of mice fed diets with or without BMSO for 11 wks. The WAT was also analyzed histologically for morphological changes. Two-dimensional gel electrophoresis (pH 4–7) revealed 32 spots showing a statistically significant difference (P<0.05) in intensity in BMSO-treated mice and 30 of these were shown to code for 23 proteins (15 increased and 8 decreased expression; >2-fold change). Combined with histological evidence of macrophage infiltration and brown adipocyte recruitment, the proteomic and immunoblotting data showed that the WAT in mice subjected to long-term high dose BMSO administration was characterized by reduced caveolae formation, increased ROS insult, tissue remodeling/repair, mitochondria uncoupling, and stabilization of the actin cytoskeleton, this last change being putatively related to an increased inflammatory response.

Conclusion

The anti-adiposity effect of BMSO is associated with WAT delipidation, inflammation, and browning. Some novel proteins participating in these processes were identified. In addition, the BMSO-mediated WAT browning may account for the increased inflammation without causing adverse metabolic effects.

Swertiamarin: An Active Lead from Enicostemma littorale Regulates Hepatic and Adipose Tissue Gene Expression by Targeting PPAR- γ and Improves Insulin Sensitivity in Experimental NIDDM Rat Model

Enicostemma littorale (EL) Blume is one of the herbs widely used for treating and alleviating the effects of both type I and type II diabetes. However, lack of understanding of mechanism precludes the use of the herb and its molecules. In this study, we attempt to unravel the molecular mechanism of action of swertiamarin, a compound isolated form EL, by comparing its molecular effects with those of aqueous EL extract in alleviating the insulin resistance in type II diabetes. We further investigated hypolipidemic and insulin sensitizing effect of swertiamarin in experimentally induced noninsulin dependent diabetes mellitus (NIDDM) in rats. Swertiamarin (50 mg/kg) and aqueous extract (15 grams dried plant equivalent extract/kg) were administered to rats orally for 40 days and tight regulation of serum glucose, insulin, and lipid profile was found in both groups. Their mode of action was by restoring G6Pase and HMG-CoA reductase activities to normal levels and restoring normal transcriptional levels of PEPCK, GK, Glut 2, PPAR-γ, leptin, adiponectin, LPL, SREBP-1c, and Glut 4 genes. This suggests that both treatments increased insulin sensitivity and regulated carbohydrate and fat metabolism. This is the first report on the role of SM in regulating the PPARγ-mediated regulation of candidate genes involved in metabolism in peripheral tissues in vivo.

Bitter melon seed oil-attenuated body fat accumulation in diet-induced obese mice is associated with cAMP-dependent protein kinase activation and cell death in white adipose tissue

The aim of this study was to investigate the antiadiposity effect of bitter melon seed oil (BMSO), which is rich in the cis-9, trans-11, trans-13 isomer of conjugated linolenic acid. In Expt. 1, C57BL/6J mice were fed a butter-based, high-fat diet [HB; 29% butter + 1% soybean oil (SBO)] for 10 wk to induce obesity. They then continued to receive that diet or were switched to an SBO-based, high-fat diet alone (HS; 30% SBO) or containing bitter melon seed oil (BMSO) (HBM; 15% SBO + 15% BMSO) for 5 wk. The body fat percentage was significantly lower in mice fed the HBM diet (21%), but not the HS diet, compared with mice fed the HB diet. In Expt. 2, mice were fed an SBO-based, high-fat diet containing 0 (HS), 5 (LBM), 10 (MBM), or 15% (HBM) BMSO for 10 wk. In the LBM, MBM, and HBM groups, the body fat percentage was significantly lower by 32, 35, and 65%, respectively, compared with the HS control. The reduction in the HBM group was significantly greater than that in the LBM or MBM group. BMSO administration increased phosphorylation of acetyl-CoA carboxylase, cAMP-activated protein kinase (PKA), and signal transducer and activator of transcription 3 in the white adipose tissue (WAT), suggesting that PKA and leptin signaling might be involved in the BMSO-mediated reduction in lipogenesis and increase in thermogenesis and lipolysis. However, compared with the HS control, the HBM group had a significantly higher TNFα concentration in the WAT accompanied by TUNEL-positive nuclei. We conclude that BMSO is effective in attenuating body fat accumulation through mechanisms associated with PKA activation and programmed cell death in the WAT, but safety concerns need to be carefully addressed.

cis-9, trans-11, trans-13-Conjugated linolenic acid induces apoptosis and sustained ERK phosphorylation in 3T3-L1 preadipocytes

OBJECTIVE

The aim of this study was to investigate the adipogenic effect of cis-9, trans-11, trans-13-conjugated linolenic acid (c9,t11,t13-CLN), a fatty acid naturally present in bitter melon.

METHODS

The 3T3-L1 murine preadipocyte cell line was used to test the effect of saponifiables from whole bitter melon and of commercially prepared pure c9,t11,t13-CLN on adipocyte differentiation. The effect of c9,t11,t13-CLN on 3T3-L1 cell viability was also tested at proliferation, mitotic clonal expansion, and terminal differentiation stages.

RESULTS

Compared to the free fatty acid control mixture, the proadipogenic effect on 3T3-L1 was less potent using saponifiables obtained from bitter melon. C9,t11,t13-CLN, unlike its non-conjugated counterpart linolenic acid (LN) or other common fatty acids such as oleic acid or linoleic acid, exerted no proadipogenic effect on 3T3-L1. In contrast to LN displaying no cytotoxic effect at a concentration ≤100 μM, c9,t11,t13-CLN caused a dose-dependent reduction in the viability of pre- and postconfluent preadipocytes associated with apoptosis. Sustained ERK/MAPK activation, accompanied by increased peroxisome proliferator-activated receptor γ phosphorylation, was seen in c9,t11,t13-CLN-treated cells at initiation of differentiation.

CONCLUSION

C9,t11,t13-CLN is less adipogenic for 3T3-L1 cells than LN and this is partly due to its apoptotic effect on proliferating preadipocytes and to the sustained ERK phosphorylation seen during mitotic clonal expansion.

Antidiabetic potentials of Momordica charantia: multiple mechanisms behind the effects

Momordica charantia fruits are used as a vegetable in many countries. From time immemorial, it has also been used for management of diabetes in the Ayurvedic and Chinese systems of medicine. Information regarding the standardization of this vegetable for its usage as an antidiabetic drug is scanty. There are many reports on its effects on glucose and lipid levels in diabetic animals and some in clinical trials. Reports regarding its mechanism of action are limited. So in the present review all the information is considered to produce some concrete findings on the mechanism behind its hypoglycemic and hypolipidemic effects. Studies have shown that M. charantia repairs damaged β-cells, increases insulin levels, and also enhance the sensitivity of insulin. It inhibits the absorption of glucose by inhibiting glucosidase and also suppresses the activity of disaccharidases in the intestine. It stimulates the synthesis and release of thyroid hormones and adiponectin and enhances the activity of AMP-activated protein kinase (AMPK). Effects of M. charantia like transport of glucose in the cells, transport of fatty acids in the mitochondria, modulation of insulin secretion, and elevation of levels of uncoupling proteins in adipose and skeletal muscles are similar to those of AMPK and thyroxine. Therefore it is proposed that effects of M. charantia on carbohydrate and fat metabolism are through thyroxine and AMPK.

Dietary kakrol (Momordica dioica Roxb.) flesh inhibits triacylglycerol absorption and lowers the risk for development of fatty liver in rats

Kakrol ( Momordica dioica Roxb.) is a cucurbitaceous vegetable native to India and Bangladesh. Bitter gourd ( Momordica charantia Linn.), a species related to kakrol, has been shown to have pharmacological properties including antidiabetic and antisteatotic effects. In this study, we investigated the effect of dietary kakrol on lipid metabolism in rats. Sprague-Dawley rats were fed AIN-76 formula diets containing 3% freeze-dried powders of whole kakrol or bitter gourd for two weeks. Results showed significantly lowered liver cholesterol and triacylglycerol levels in rats fed on both diets. Fecal lipid excretion increased in rats fed the kakrol diet, and lymphatic transport of triacylglycerol and phospholipids decreased in rats fed the kakrol diet after permanent lymph cannulation. Furthermore, n-butanol extract from kakrol caused a significant concentration-dependent decrease in the pancreatic lipase activity in vitro. These results indicate that the mechanisms of action on lipid metabolism in kakrol and bitter gourd are different and that dietary kakrol reduces liver lipids by inhibiting lipid absorption.

Effects of Atractylodes macrocephala Koidzumi rhizome on 3T3-L1 adipogenesis and an animal model of obesity

ETHNOPHARMACOLOGICAL RELEVANCE

Atractylodes macrocephala Koidzumi (AMK) is an herbal medicine traditionally used for treatment of abdominal pain, gastrointestinal disease, obesity, and related complications.

AIM OF THE STUDY

We investigated the effects and molecular mechanism of AMK rhizome water extract on 3T3-L1 adipogenesis and an animal model of obesity.

MATERIALS AND METHODS

To study the effect of AMK on adipogenesis in vitro, differentiating 3T3-L1 cells were treated every two days with AMK at various concentrations (1-25μg/ml) for eight days. Oil Red O staining was performed to determine the lipid accumulation in 3T3-L1 cells. To elucidate the inhibitory mechanism of AMK on adipogenesis, phosphorylation levels of Akt and expression of perilipin, were analyzed by Western blotting. AMK was administered orally to high fat diet (HFD)-induced obese rats to confirm its effect in vivo.

RESULTS

AMK inhibited 3T3-L1 adipocyte differentiation in a dose-dependent manner without cellular toxicity. Phospho-Akt expression was highly decreased by AMK treatment, whereas there was no significant change in perilipin expression. AMK administration significantly reduced the body weight of rats fed a HFD. Plasma triglyceride levels were significantly lower in the AMK-treated HFD group than those in the HFD control group or normal diet (ND) group, although serum total, HDL- and LDL-cholesterol levels did not differ between the groups.

CONCLUSION

These results demonstrate an inhibitory effect of AMK on adipogenesis through reduction of an adipogenic factor, phospho-Akt. AMK had a beneficial effect, reducing body weight gain in a HFD-induced animal model of obesity.

Pathogenic obesity and nutraceuticals

Over a decade of intense research in the field of obesity has led to the knowledge that chronic, excessive adipose tissue expansion leads to an increase in the risk for CVD, type 2 diabetes mellitus and cancer. This is primarily thought to stem from the low-grade, systemic inflammatory response syndrome that characterises adipose tissue in obesity, and this itself is thought to arise from the complex interplay of factors including metabolic endotoxaemia, increased plasma NEFA, hypertrophic adipocytes and localised hypoxia. Plasma concentrations of vitamins and antioxidants are lower in obese individuals than in the non-obese, which is hypothesised to negatively affect the development of inflammation and disease in obesity. This paper provides a review of the current literature investigating the potential of nutraceuticals to ameliorate the development of oxidative stress and inflammation in obesity, thereby limiting the onset of obesity complications. Research has found nutraceuticals able to positively modulate the activity of adipocyte cell lines and further positive effects have been found in other aspects of pathogenic obesity. While their ability to affect weight loss is still controversial, it is clear that they have a great potential to reverse the development of overweight and obesity-related comorbidities; this, however, still requires much research especially that utilising well-structured randomised controlled trials.

Effects of Korean white ginseng extracts on obesity in high-fat diet-induced obese mice

The present study examined the anti-obesity effect and mechanism of action of Korean white ginseng extracts (KGE) using high-fat diet (HFD)-induced obese mice. Mice were fed a low-fat diet (LFD), HFD or HFD containing 0.8 and 1.6% (w/w) KGE diet (HFD + 0.8KGE and HFD + 1.6KGE) for 8 weeks. We also examined the effects of KGE on plasma triglyceride (TG) elevation in mice administrated with oral lipid emulsion. Body weight gain and white adipose tissue (WAT) weight were significantly decreased in the HFD + 1.6KGE group, compared with the HFD group. The plasma TG levels were also significantly reduced in both HFD + 0.8KGE and HFD + 1.6KGE groups, while leptin levels were significantly decreased in only the HFD + 1.6KGE group, compared with the HFD group. The HFD + 1.6KGE group showed significantly lower mRNA levels of lipogenesis-related genes, including peroxisome proliferator-activated receptorγ2 (PPARγ2), sterol regulatory element binding protein-1c (SREBP-1c), lipoprotein lipase (LPL), fatty acid synthase (FAS) and diacylglycerol acyltransferase 1 (DGAT1), compared with the HFD group. In addition, a dose of 1000 mg/kg KGE inhibited the elevation of plasma TG levels compared with mice given the lipid emulsion alone. These results suggest that the anti-obesity effects of KGE may be elicited by regulating expression of lipogenesis-related genes in WAT and by delaying intestinal fat absorption.

Antidiabetic effects of bitter gourd extracts in insulin-resistant db/db mice

Bitter gourd (BG, Momordica charantia) exerts proven blood glucose- and body weight-lowering effects. To develop an effective and safe application, it is necessary to identify the bioactive compounds and biochemical mechanisms responsible for these effects in type 2 diabetes. A total of forty-five 4-week-old male db/db mice were assigned to five groups of nine each. The mice were given sterile tap water as a control, a whole fruit powder, the lipid fraction, the saponin fraction or the hydrophilic residue of BG at a daily oral dosage of 150 mg/kg body weight for 5 weeks, respectively. Weight gain was significantly decreased in all the BG-treated groups (P ≤ 0.05). Glycated Hb levels were the highest in the control mice compared with all the four BG-treated mice (P = 0.02). The lipid fraction had the strongest effect, and it tended (P = 0.075) to reduce glycated Hb levels from 9.3 % (control mice) to 8.0 % (lipid fraction-treated mice). The lipid and saponin fractions reduced lipid peroxidation of adipose tissue significantly (P ≤ 0.01). Additionally, the saponin fraction and the lipid fraction reduced protein tyrosine phosphatase 1B (PTP 1B) activity in skeletal muscle cytosol by 25 % (P = 0.05) and 23 % (P = 0.07), respectively. PTP 1B is the physiological antagonist of the insulin signalling pathway. Inhibition of PTP 1B increases insulin sensitivity. This is the first study to demonstrate that BG is involved in PTP 1B regulation, and thus explains one possible biochemical mechanism underlying the antidiabetic effects of BG in insulin resistance and type 2 diabetes.

Momordica charantia (bitter melon) inhibits primary human adipocyte differentiation by modulating adipogenic genes

BACKGROUND

Escalating trends of obesity and associated type 2 diabetes (T2D) has prompted an increase in the use of alternative and complementary functional foods. Momordica charantia or bitter melon (BM) that is traditionally used to treat diabetes and complications has been demonstrated to alleviate hyperglycemia as well as reduce adiposity in rodents. However, its effects on human adipocytes remain unknown. The objective of our study was to investigate the effects of BM juice (BMJ) on lipid accumulation and adipocyte differentiation transcription factors in primary human differentiating preadipocytes and adipocytes.

METHODS

Commercially available cryopreserved primary human preadipocytes were treated with and without BMJ during and after differentiation. Cytotoxicity, lipid accumulation, and adipogenic genes mRNA expression was measured by commercial enzymatic assay kits and semi-quantitative RT-PCR (RT-PCR).

RESULTS

Preadipocytes treated with varying concentrations of BMJ during differentiation demonstrated significant reduction in lipid content with a concomitant reduction in mRNA expression of adipocyte transcription factors such as, peroxisome proliferator-associated receptor gamma (PPARgamma) and sterol regulatory element-binding protein 1c (SREBP-1c) and adipocytokine, resistin. Similarly, adipocytes treated with BMJ for 48 h demonstrated reduced lipid content, perilipin mRNA expression, and increased lipolysis as measured by the release of glycerol.

CONCLUSION

Our data suggests that BMJ is a potent inhibitor of lipogenesis and stimulator of lipolysis activity in human adipocytes. BMJ may therefore prove to be an effective complementary or alternative therapy to reduce adipogenesis in humans.

Anti-diabetic and hypoglycaemic effects of Momordica charantia (bitter melon): a mini review

It has been estimated that up to one-third of patients with diabetes mellitus use some form of complementary and alternative medicine. Momordica charantia (bitter melon) is a popular fruit used for the treatment of diabetes and related conditions amongst the indigenous populations of Asia, South America, India and East Africa. Abundant pre-clinical studies have documented the anti-diabetic and hypoglycaemic effects of M. charantia through various postulated mechanisms. However, clinical trial data with human subjects are limited and flawed by poor study design and low statistical power. The present article reviews the clinical data regarding the anti-diabetic potentials of M. charantia and calls for better-designed clinical trials to further elucidate its possible therapeutic effects.

No effect of acute, single dose oral administration of Momordica charantia Linn., on glycemia, energy expenditure and appetite: a pilot study in non-diabetic overweight men

AIM OF THE STUDY

Momordica charantia Linn. Cucurbitaceae (MC), has been used to treat glycemic impairment in humans for centuries. The objective of this study was to determine the acute effect of MC on postprandial glucose levels, energy expenditure/fuel mixture and appetite in overweight men.

MATERIALS AND METHODS

Five healthy overweight men were supplemented on three randomized conditions where (1) no MC (placebo), (2) 50 mg/kg body weight (MC50) or (3) 100 mg/kg body weight of freeze dried MC were administered orally prior to a 75 g oral glucose tolerance test (OGTT). Plasma glucose and insulin levels were measured before and during the OGTT. Energy expenditure as well as carbohydrate and lipid oxidation rates were measured by indirect calorimetry. Visual analogue scales were used to rate appetite profile.

RESULTS

Plasma glucose and insulin levels significantly increased during the OGTT (p < or =0.05) but no significant difference was observed between experimental conditions. Energy expenditure, carbohydrate and lipid oxidation rates as well as appetite profile did not differ between experimental conditions.

CONCLUSIONS

These results suggest that from an acute standpoint, a freeze dried MC extraction in its present dose form does not affect plasma glucose/insulin levels, energy expenditure, substrate mixture and appetite scores following an oral glucose load in non-diabetic overweight men.

A systematic review of the efficacy and safety of herbal medicines used in the treatment of obesity

This review focuses on the efficacy and safety of effective herbal medicines in the management of obesity in humans and animals. PubMed, Scopus, Google Scholar, Web of Science, and IranMedex databases were searched up to December 30, 2008. The search terms were "obesity" and ("herbal medicine" or "plant", "plant medicinal" or "medicine traditional") without narrowing or limiting search elements. All of the human and animal studies on the effects of herbs with the key outcome of change in anthropometric measures such as body weight and waist-hip circumference, body fat, amount of food intake, and appetite were included. In vitro studies, reviews, and letters to editors were excluded. Of the publications identified in the initial database, 915 results were identified and reviewed, and a total of 77 studies were included (19 human and 58 animal studies). Studies with Cissus quadrangularis (CQ), Sambucus nigra, Asparagus officinalis, Garcinia atroviridis, ephedra and caffeine, Slimax (extract of several plants including Zingiber officinale and Bofutsushosan) showed a significant decrease in body weight. In 41 animal studies, significant weight loss or inhibition of weight gain was found. No significant adverse effects or mortality were observed except in studies with supplements containing ephedra, caffeine and Bofutsushosan. In conclusion, compounds containing ephedra, CQ, ginseng, bitter melon, and zingiber were found to be effective in the management of obesity. Attention to these natural compounds would open a new approach for novel therapeutic and more effective agents.