Anti-obesity effects of chikusetsusaponins isolated from Panax japonicus rhizomes

Inhibitors of pancreatic lipase: state of the art and clinical perspectives

Obesity is a disorder of lipid metabolism and continues to be a global problem, ranking fifth for deaths worldwide. It also leads to diabetes, cardiovascular disorders, musculoskeletal disorders and some types of cancer. Obesity is regarded as the output of a long-term imbalance between energy intake and energy expenditure. Digestion and absorption of dietary lipids by pancreatic lipase, a major source of excess calorie intake, can be targeted for development of anti-obesity agents. Being the major factor of concern, food materials and edible plants are most widely studied for the anti-obesity activity, so that they can be incorporated in the routine diet. In this review, an attempt was made to present a current scenario of the bioactive compounds from plant and microbial origin that have been investigated for their pancreatic lipase inhibition. Compounds belonging to various classes of natural products such as alkaloids, carotenoids, glycosides, polyphenols, polysaccharides, saponins and terpenoids are well studied while lipophilic compounds from microbial sources are the most active against the pancreatic lipase. Few studies on the synthetic analogues, structurally similar to the triglycerides have been described in the review. Despite of tremendous research on the finding of potential pancreatic lipase inhibitor, very few compounds have entered the clinical studies and no new molecule after orlistat has been marketed. Along with HTS based screening, detailed structure-activity relationship studies on semi-synthetic and synthetic derivatives might also provide a direction for the development of potential lead(s) or pharmacophore for pancreatic lipase inhibition in order to treat and/or prevent obesity and related disorders.

Chikusetsu saponin V attenuates MPP+-induced neurotoxicity in SH-SY5Y cells via regulation of Sirt1/Mn-SOD and GRP78/caspase-12 pathways

Studies have shown that saponins from Panax japonicus (SPJ) possess neuroprotective effects. However, whether Chikusetsu saponin V (CsV), the most abundant member of SPJ, can exert neuroprotective effects against 1-methyl-4-phenylpyridinium ion (MPP⁺)-induced cytotoxicity is not known. In this study, we aimed to investigate the neuroprotective effects of CsV on MPP⁺-induced cytotoxicity in human neuroblastoma SH-SY5Y cells and explore its possible mechanisms. Our results show that CsV attenuates MPP⁺-induced cytotoxicity, inhibits ROS accumulation, and increases mitochondrial membrane potential dose-dependently. We also found that levels of Sirt1 protein and Mn-SOD mRNA significantly decreased in MPP⁺-treated group but were restored with CsV treatment in a dose-dependent manner. Furthermore, GRP78 protein and Caspase-12 mRNA levels were elevated by MPP⁺ exposure but reversed by CsV treatment. CsV inhibited the MPP⁺-induced downregulation of Bcl-2 and up-regulation of Bax in a dose-dependent manner and, thus, increased the ratio of Bcl-2/Bax. Overall, these results suggest that Sirt1/Mn-SOD and GRP78/Caspase-12 pathways might be involved in the CsV-mediated neuroprotective effects.

Inhibition of Increases in Blood Glucose and Serum Neutral Fat byMomordica charantiaSaponin Fraction

Focusing on a functional component of Momordica charantia, saponin, we investigated its effects on serum glucose and neutral fat levels. Saponin was extracted as a butanol-soluble fraction (saponin fraction) from hot blast-dried Momordica charantia powder. The disaccharidase-inhibitory activity and the pancreatic lipase-inhibitory activity of the saponin fraction were measured, and in vivo sugar- and lipid-loading tests were performed. The saponin fraction inhibited disaccharidase activity and elevation of the blood glucose level after sucrose loading. The fraction also markedly inhibited pancreatic lipase activity and elevation of the serum neutral fat level after corn oil loading. Based on these findings, the main active component related to the anti-diabetic effect of Momordica charantia is present in the butanol fraction, and it may be saponin. The blood glucose and serum neutral fat-lowering effects of Momordica charantia were closely associated with its inhibitory activity against disaccharidase and pancreatic lipase.

Effect of Coleus forskohlii extract on cafeteria diet-induced obesity in rats

BACKGROUND

Obesity is a metabolic disorder that can lead to adverse metabolic effects on blood pressure, cholesterol, triglycerides and insulin resistance and also increases the risk of coronary heart disease, ischemic stroke and type 2 diabetes mellitus. This study was designed to determine the effect of Coleus forskohlii on obesity and associated metabolic changes in rats fed with cafeteria diet.

OBJECTIVE

The aim of this study was to evaluate antiobesogenic and metabolic benefits of C. forskohlii in cafeteria diet induced obesity rat model.

MATERIALS AND METHODS

RATS WERE RANDOMLY DIVIDED INTO FIVE GROUPS OF SIX ANIMALS IN EACH GROUP AND AS FOLLOWS: Normal pellet diet group; cafeteria diet group; cafeteria diet followed by 50 mg/kg/d Coleus forskohlii extract (CFE), 100 mg/kg/d CFE and 45 mg/kg/d orlistat groups, respectively. Indicators of obesity such as food intake, body weight and alteration in serum lipid profiles were studied.

RESULTS

Feeding of cafeteria diet induced obesity in rats. Administration of CFE significantly halted increase in food intake and weight gain associated with cafeteria diet. Development of dyslipidemia was also significantly inhibited.

CONCLUSION

The observed effects validate that supplementation of CFE with cafeteria diet could curb the appetite and mitigate the development of dyslipidemia.

Effects of two sulfated triterpene saponins echinoside A and holothurin A on the inhibition of dietary fat absorption and obesity reduction

Two similarly sulfated triterpene saponins from Pearsonothuria graeffei were prepared to investigate the anti-obesity effects of echinoside A (EA) and holothurin A (HA). The in vitro inhibitory activities of EA and HA toward pancreatic lipase were investigated, and two in vivo studies were performed: (i) Male Wistar rats were orally administered the lipid emulsion with or without a saponin (HA or EA). The serum’s total triglyceride concentration was measured at various times. (ii) C57BL/6 mice were assigned to four groups, high fat (HF), EA (0.03%), HA (0.04%), and orlistat (0.01%), and the weight of adipose tissue and level of fatty acids excreted in the feces were determined. Both EA and HA repressed the pancreatic lipase activity and increased fatty acid excretion in the feces. Treatment with EA and HA significantly decreased the adipose tissue accumulation in mice. EA and HA manifested different inhibitory activities in vitro, but each of them dramatically inhibited lipid absorption in vivo and showed strong anti-obesity activity.

Anti- and pro-lipase activity of selected medicinal, herbal and aquatic plants, and structure elucidation of an anti-lipase compound

Plants that help in slowing down the digestion of triacylglycerols (TAGs) in the pancreas and small intestine of humans play an important role in the reduction of obesity. On the other hand, there may be plants or plant parts that stimulate intestinal lipolytic activity, thus contributing to greater TAG assimilation. The aim of this study was to evaluate the aqueous methanolic extracts of ninety eight (98) medicinal, herbal and aquatic plant materials from Malaysia for their effect on porcine pancreatic lipase (PPL) activity and to identify the structure of an anti-lipase compound from one of the sources. The degree of inhibition was also quantified as relative to orlistat activity against PPL (orlistat equivalents). Results revealed that while 19.4% of the extracts were found to have anti-lipase activity ≥80%, 12% were actually found to promote PPL activity. Twenty two percent (22.4%) exhibited moderate inhibition (41%-80%) and 2% were neutral toward PPL activity. The ripe fruit of Averrhoa carambola and the leaves of Archidendron jiringa (Jack) I.C Nielsen L. (jering), Cynometra cauliflora (nam-nam) and Aleurites moluccana (L.) Willd (candle nut/buah keras) had the highest (100%) anti-lipase activity and are equivalent to 0.11 µg orlistat/mL. Plants that stimulated lipase activity included Pimpinella anisum L. (aniseed/jintan manis), activating the enzyme by 186.5%. Kaempferol 3-O-rhamnoside was isolated from the ethyl acetate fraction of C. cauliflora leaves and found to be an active lipase inhibitor. The structure was elucidated using 1H-NMR, 13C-NMR and 2D-NMR analyses.

Determination of chikusetsusaponin V and chikusetsusaponin IV in rat plasma by liquid chromatography-mass spectrometry and its application to a preliminary pharmacokinetic study

A sensitive liquid chromatography-electrospray ionization-mass spectrometry method has been developed and validated for determination of two major bioactive saponins in rat plasma after oral administration of saponins extracted from Rhizoma Panacis Japonici, including chikusetsusaponin V and chikusetsusaponin IV for the first time. Akebia saponin D was used as the internal standard (IS). Plasma samples were prepared by protein precipitation with methanol. A Phenomenex C18 column (150 × 4.6 mm, 4 µm) was used as the analytical column with a mobile phase of acetonitrile and 0.05% aqueous formic acid. Mass spectrometric detection was achieved by single quadrupole mass spectrometer equipped with an electrospray ionization interface operating in negative ionization mode. Calibration curves showed good linearity over the concentration range of 5-500 ng/mL for the two analytes in rat plasma. The lower limit of quantification was 5 ng/mL. The intra- and inter-batch precisions were within 10.3% and accuracy ranged from -3.9 to 5.4%. The method was validated and successfully applied to the preliminary pharmacokinetic study of chikusetsusaponin V and chikusetsusaponin IV in rat plasma after oral administration of saponins extracted from Rhizoma Panacis Japonici.

Food ingredients as anti-obesity agents: a review

Overweight and obesity have a major impact on global health; their prevalence has rapidly increased in all industrialized countries in the past few decades and diabetes and hypertension are their direct consequences. Pharmacotherapy provides reinforcement for obesity treatment, but should be an adjunctive support to diet, exercise, and lifestyle modification. At present, only orlistat and sibutramine have been approved by the US Food and Drug Administration for long-term use, but sibutramine was withdrawn for sale by the European Medicines Agency. The development of functional foods for the prevention and/or treatment of obesity suppose an opportunity for the food market and involve the knowledge of the mechanisms of appetite and energy expenditure as well as the metabolic sensation of satiety. Strategies for weight control management affect gut hormones as potential targets for the appetite metabolic regulation, stimulation of energy expenditure (thermogenesis), and modifications in the metabolic activity of the gut microbiota. Functional foods for obesity may also include bioactive fatty acids, phenolic compounds, soybean, plant sterols, dietary calcium, and dietary fiber. This review intends to offer an overview of the present situation of the anti-obesity agents currently used in dietary therapy as well as some functional food ingredients with potentially anti-obesity effects.

The activity of mate saponins (Ilex paraguariensis) in intra-abdominal and epididymal fat, and glucose oxidation in male Wistar rats

ETHNOPHARMACOLOGICAL RELEVANCE

Ilex paraguariensis A. St. Hilaire (mate) has traditionally been used in several South American countries to prepare tea-like beverages having stimulant effects on the CNS and appetite. In recent years, however, mate preparations have been recommended putatively as an appetite suppressant and slimming remedy. Moreover, studies carried out on either normal or diet-induced obese rats treated with mate extracts revealed anti-obesity and satiety effects, thus refuting ethnopharmacological data. In this work, the effect of mate on the intra-abdominal and epididymal fat, and glucose oxidation levels after oral administration in male Wistar rats, was studied using crude extract from leaves, unripe fruits, and a chemically well-defined purified saponin fraction (MSF).

MATERIAL AND METHODS

Saponin, polyphenol and methylxanthine contents in MSF were analyzed by HPLC-PDA and UPLC/Q-TOF-MS. Crude extracts from mate leaves (LAE) and unripe fruits (FHE) were assayed for comparison purposes. Male Wistar rats fed with standard diet and water ad libitum were used as the control group.

RESULTS

The fat weight and both liver and adipose glucose oxidation were reduced significantly by MSF (35, 90 and 60%, respectively), while LAE and FHE were less active. Also, a significant lowering of the blood triglycerides level was observed in rats treated with MSF and LAE. All creatinine, urea, and transaminase plasma levels remained unaffected no matter what mate preparation was considered. It is also worth pointing out that the glucose blood level was increased after treatment with FHE. This finding did not correlate either with the content of methylxanthines, polyphenols or saponins.

CONCLUSION

A reduction in both visceral fat weight and glucose oxidation of hepatic and adipose tissue in healthy rats fed with a standard diet could be ascribed to a purified mate saponin fraction from unripe fruits. These findings agree with former studies carried out with crude mate extracts and also suggest their potential use as an anti-obesity preparation. Nonetheless, further in vivo experiments are still required to corroborate its effect on human beings.

Natural products: a safest approach for obesity

Obesity is recognized as a social problem, associated with serious health risks and increased mortality. Numerous trials have been conducted to find and develop new anti-obesity drugs through herbal sources to minimize adverse reactions associated with the present anti-obesity drugs. The use of natural products as medicine has been documented for hundreds of years in various traditional systems of medicines throughout the world. This review focuses on the medicinal plants such as Achyranthus aspera, Camellia sinensis, Emblica officinalis, Garcinia cambogia, Terminalia arjuna, etc., being used traditionally in Ayurvedic, Unani, Siddha and Chinese, etc., systems of medicine. The review also highlights recent reported phytochemicals such as escins, perennisosides, dioscin, gracillin, etc., and the various extracts of the plants like Nelumbo nucifera, Panax japonicas, Cichorium intybus, Cyperus rotundus, Paeonia suffruticosa, etc., which have been successfully identified for the treatment of obesity.

Adverse metabolic effects of a hypercaloric, high-fat diet in rodents precede observable changes in body weight

Although a high-fat diet (HFD) is recognized as an important contributor to obesity, human research is limited by confounders such as income, whereas animal research has typically examined diet during specific developmental periods rather than throughout the lifespan. We hypothesized that the use of an HFD in short-term studies as has been commonly done in animals does not adequately reflect the lifelong dietary patterns seen frequently in humans with consequent metabolic disturbances. We examined the impact of HFD from weaning until 39 weeks (middle age) on the metabolism of male rats. At 7, 26, and 39 weeks, glucose tolerance tests were performed, a subset of animals was euthanized, and serum and tissues were collected. After 4 weeks, preceding increased body weight, HFD animals had increased intra-abdominal fat, triglycerides, and hyperglycemia. Hyperinsulinemia was insufficient to maintain normoglycemia, and beta cell mass and glucagon-like peptide 1 decreased over time in HFD and control animals. Despite lacking significant lipid abnormalities, nonalcoholic fatty liver disease was evident by 39 weeks. Our HFD model demonstrated that significant metabolic abnormalities may go undetected by current standard screening such as weighing and biochemistry.

Korean red ginseng (Panax ginseng) improves insulin sensitivity in high fat fed Sprague-Dawley rats

Many studies have documented that ginseng has antidiabetic and antiobesity effects, but the mechanism of the effects has not been elucidated. The aim of this study was to determine the effect of Korean red ginseng (KRG, Panax ginseng) and investigate the mechanism of antidiabetic and antiobesity effects in obese insulin resistant animal models. Sprague-Dawley (SD) rats were divided into three groups: a control group (group I) fed a normal diet, another group (group II) fed only high fat diet (HFD) and a third group (group III) fed HFD with KRG (200 mg/kg, oral) for 18 weeks. The body weight, food intake, adipose tissues, liver, kidney, pancreas, adiponectin, and leptin were measured. Blood glucose, insulin tolerance test, and hyperinsulinemic euglycemic clamp test were investigated. A significant weight reduction, especially fat mass reduction, was observed in the KRG treated group. Increased insulin sensitivity was found in the KRG treated group. We observed increased insulin signalling, increased phosphorylation of IR, IRS-1, Akt, and membranous GLUT4 in muscle by Western blotting assay. In conclusion, KRG may have antidiabetic and antiobesity effects due to partly increased insulin sensitivity by increased adipokine and partly enhanced insulin signalling.

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.

Antihyperlipidemic activity of Ichnocarpus frutescens in triton WR-1339-induced and high-fat diet animals

CONTEXT

Ichnocarpus frutescens (L.) R.Br. (Apocynaceae) is used to treat diabetes and hyperlipidemia in folk medicine.

OBJECTIVE

The crude methanol extract and fractions of I. frutescens were investigated for antihyperlipidemic effect.

MATERIALS AND METHODS

Fresh leaves of I. frutescens were extracted with methanol and fractionated with hexane, benzene, ethyl acetate, acetone, and methanol. The active acetone fraction was subfractionated, which resulted in active fraction 3. The antihyperlipidemic effects of the methanol extract and fractions of I. frutescens were studied in triton WR-1339-induced and high-fat diet (HFD) obese animals. Further, lipid absorption and excretion were studied.

RESULTS AND DISCUSSION

The methanol extract significantly reduced total cholesterol (TC) by 29.63% and triglyceride (Tg) by 51.10% at 400 mg/kg in triton WR-1339-induced animals and significantly reduced TC (27.81%) and Tg (37.03%) at 400 mg/kg in HFD animals. Fraction 3 showed significant reduction in TC (25.03%) and Tg (58.05%) at 200 mg/kg. Feeding of HFD consisting 3% of fraction 3 increased feces weight and Tg level in mice. Fraction 3, showed significant decrease in plasma Tg level at the second hour, after oral administration of the lipid emulsion to rats.

CONCLUSION

The observed properties apparently validate the folk medicinal use of this plant in amelioration of hyperlipidemia.

Effect of Argyreia speciosa root extract on cafeteria diet-induced obesity in rats

OBJECTIVES

To evaluate the antiobesity effects of the ethanolic extract of Argyreia speciosa roots in rats fed with a cafeteria diet (CD).

MATERIALS AND METHODS

Obesity was induced in albino rats by feeding them a CD daily for 42 days, in addition to a normal diet. Body weight and food intake was measured initially and then every week thereafter. On day 42, the serum biochemical parameters were estimated and the animals were sacrificed with an overdose of ether. The, liver and parametrial adipose tissues were removed and weighed immediately. The liver triglyceride content was estimated. The influence of the extract on the pancreatic lipase activity was also determined by measuring the rate of release of oleic acid from triolein.

RESULTS

The body weight at two-to-six weeks and the final parametrial adipose tissue weights were significantly lowered (P < 0.01 and P < 0.05, respectively) in rats fed with the CD with Argyreia speciosa extract 500 mg/kg/day as compared to the CD alone. The extract also significantly reduced (P < 0.01) the serum contents of leptin, total cholesterol, low density lipoprotein (LDL), and triglycerides, which were elevated in rats fed with CD alone. In addition, the extract inhibited the induction of fatty liver with the accumulation of hepatic triglycerides. The extract also showed inhibition of pancreatic lipase activity by using triolein as a substrate.

CONCLUSIONS

The ethanolic extract of Argyreia speciosa roots produces inhibitory effects on cafeteria diet-induced obesity in rats.

Carnosic acid-rich rosemary (Rosmarinus officinalis L.) leaf extract limits weight gain and improves cholesterol levels and glycaemia in mice on a high-fat diet

Rosemary (Rosmarinus officinalis L.) extracts (RE) are natural antioxidants that are used in food, food supplements and cosmetic applications; exert anti-inflammatory and anti-hyperglycaemic effects; and promote weight loss, which can be exploited to develop new preventive strategies against metabolic disorders. Therefore, the aim of the present study was to evaluate the preventive effects of rosemary leaf extract that was standardised to 20 % carnosic acid (RE) on weight gain, glucose levels and lipid homeostasis in mice that had begun a high-fat diet (HFD) as juveniles. The animals were given a low-fat diet, a HFD or a HFD that was supplemented with 500 mg RE/kg body weight per d (mpk). Physiological and biochemical parameters were monitored for 16 weeks. Body and epididymal fat weight in animals on the HFD that was supplemented with RE increased 69 and 79 % less than those in the HFD group. Treatment with RE was associated with increased faecal fat excretion but not with decreased food intake. The extract also reduced fasting glycaemia and plasma cholesterol levels. In addition, we evaluated the inhibitory effects of RE in vitro on pancreatic lipase and PPAR-γ agonist activity; the in vitro findings correlated with our observations in the animal experiments. Thus, the present results suggest that RE that is rich in carnosic acid can be used as a preventive treatment against metabolic disorders, which merits further examination at physiological doses in randomised controlled trials.

Characterization and identification of saponins in Achyranthes bidentata by rapid-resolution liquid chromatography with electrospray ionization quadrupole time-of-flight tandem mass spectrometry

A rapid-resolution liquid chromatography (RRLC) method coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (Q-TOF MS/MS) has been developed for analysis of oleanane-type triterpenoid saponins in Achyranthes bidentata. Collision-induced dissociation techniques were used to fragment the precursor molecular ions and the resulting product ions. A retro-Diels-Alder rearrangement from the oleanane aglycone skeleton in the MS/MS process yielded characteristic fragment ions in positive ion mode. These characteristic ions were helpful in predicting the aglycone structure. Losses of monosaccharide sequences, presence of sugar-chain fragment ions, and cleavage of CO(2) were observed for important information on sugar types and attachment sequences. Fragmentation rules of three major groups of saponins from A. bidentata were summarized, and the possible fragmentation pathways were proposed. A total of 22 compounds including both the target and unknown oleanane-type triterpenoid saponins were rapidly screened and predicted in the herbal extract by the developed method. The RRLC-Q-TOF MS/MS method has provided a powerful approach for rapid separation, target screening and structural elucidation of oleanane-type saponins, and also opened perspectives for similar studies on other herbal medicines.

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.

Anti-Obesity effects of protopanaxdiol types of Ginsenosides isolated from the leaves of American ginseng (Panax quinquefolius L.) in mice fed with a high-fat diet

Effects of protopanaxdiol (PDG) and protopanaxatriol (PTG) types of ginsenosides isolated from the leaves of American ginseng on porcine pancreatic lipase activity were determined in vitro. PDG inhibited the pancreatic lipase activity in a dose-dependent manner at the concentrations of 0.25-1mg/ml. It inhibited hydrolysis of about 83.2% of triolein at about 1mg/ml of PDG. However, PTG showed no inhibitory activity. Therefore, anti-obesity activity of PDG was evaluated in mice fed a high-fat diet. The results demonstrated that PDG was effective in preventing and healing obesity, fatty liver and hypertriglyceridemia in mice fed with a high-fat diet.

The role of lipid and carbohydrate digestive enzyme inhibitors in the management of obesity: a review of current and emerging therapeutic agents

Obesity is a global epidemic associated with significant morbidity and mortality in adults and ill health in children. A proven successful approach in weight management has been the disruption of nutrient digestion, with orlistat having been used to treat obesity for the last 10 years. Although orlistat-induced weight loss remains modest, it produces meaningful reductions in risk factors for obesity-related conditions such as diabetes and cardiovascular disease. Moreover, this lipase inhibitor is free of the serious side effects that have dogged appetite-suppressing drugs. This success had driven investigation into new generation nutraceuticals, supplements and pharmaceutical agents that inhibit the breakdown of complex carbohydrates and fats within the gut. This review focuses on agents purported to inhibit intestinal enzymes responsible for macronutrient digestion. Except for some synthetic products, the majority of agents reviewed are either botanical extracts or bacterial products. Currently, carbohydrate digestion inhibitors are under development to improve glycemic control and these may also induce some weight loss. However, colonic fermentation induced side effects, such as excess gas production, remain an issue for these compounds. The α-glucosidase inhibitor acarbose, and the α-amylase inhibitor phaseolamine, have been used in humans with some promising results relating to weight loss. Nonetheless, few of these agents have made it into clinical studies and without any clinical proof of concept or proven efficacy it is unlikely any will enter the market soon.

Toxicity and genotoxicity evaluation of Passiflora alata Curtis (Passifloraceae)

Passiflora alata is an official species of Brazilian Pharmacopoeia and its aerial parts are used as medicinal plant by local population as well as constitutes many phytomedicines commercialized in Brazil as sedative.

AIMS OF STUDY

To evaluate the acute and sub-acute toxicity and genotoxicity of an aqueous spray-dried extract (PA) of Passiflora alata (2.6% flavonoids).

MATERIALS AND METHODS

The acute and the sub-acute toxicity was evaluated in mice and rats, respectively. Behavioural, biochemical, hematological, histological and urine parameters were considered. Genotoxicity was assessed by using micronucleus test performed in peripheral blood and bone marrow cells and comet assay in peripheral blood leukocytes.

RESULTS

Mice deaths were not observed up to 4800 mg/kg, p.o., single dose. Rats treated with aqueous extract at dose of 300 mg/kg, p.o., for 14 days did not present biochemical, hematological or histopathological significant alterations when compared to control group. However, these rats showed signs of irritability and did not show weight gain. In addition, mice acutely treated with extract 150, 300 and 600 mg/kg, p.o., presented DNA damage determined by comet assay in peripheral blood cells 3h after treatment. The effect of lower doses (12.5, 25 and 50mg/kg, p.o.) was evaluated at 3, 6 and 24h after treating. Only PA 50mg/kg (p.o.) induced significant damage at 3 and 6h. The maximum damage induction was observed at 6h. When the animals received PA 12.5, 25 or 50mg/kg/day during 3 days (i.e., 72h treatment) DNA damage (comet and micronucleus tests) increased significantly in a dose-dependent manner.

CONCLUSION

In conclusion Passiflora alata presented genotoxic effect and deserves further toxicity evaluation in order to guarantee its safety for human use.

Korean red ginseng (Panax ginseng) improves insulin sensitivity and attenuates the development of diabetes in Otsuka Long-Evans Tokushima fatty rats

Ginseng has been reported to ameliorate hyperglycemia in experimental and clinical studies; however, its mechanism of action remains unclear. In this study, we investigated the metabolic effects and putative molecular mechanisms of Korean red ginseng (KRG, Panax ginseng) in animal models for type 2 diabetes mellitus (T2DM) and peripheral insulin-responsive cell lines. Korean red ginseng was administered orally at a dose of 200 mg/(kg d) to Otsuka Long-Evans Tokushima fatty rats for 40 weeks. Initially, chronic administration of KRG reduced weight gain and visceral fat mass in the early period without altering food intake. The KRG-treated Otsuka Long-Evans Tokushima fatty rats showed improved insulin sensitivity and significantly preserved glucose tolerance compared with untreated control animals up to 50 weeks of age, implying that KRG attenuated the development of overt diabetes. KRG promoted fatty acid oxidation by the activation of adenosine monophosphate-activated protein kinase (AMPK) and phosphorylation of acetyl-coenzyme A carboxylase in skeletal muscle and cultured C2C12 muscle cells. Increased expression of peroxisome proliferator-activated receptor-gamma coactivator-1alpha, nuclear respiratory factor-1, cytochrome c, cytochrome c oxidase-4, and glucose transporter 4 by KRG treatment indicates that activated AMPK also enhanced mitochondrial biogenesis and glucose utilization in skeletal muscle. Although these findings suggest that KRG is likely to have beneficial effects on the amelioration of insulin resistance and the prevention of T2DM through the activation of AMPK, further clinical studies are required to evaluate the use of KRG as a supplementary agent for T2DM.

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.

Oleanane-type triterpene oligoglycosides with pancreatic lipase inhibitory activity from the pericarps of Sapindus rarak

The methanolic extract from the pericarps of Sapindus rarak DC. was found to show pancreatic lipase inhibitory activity (IC50=ca. 614 microg/mL). From the extract, oleanane-type triterpene oligoglycosides, rarasaponins I-III (1-3), and raraoside A (4), were isolated together with 13 known saponins and four known sesquiterpene glycosides. Among them, several saponin constituents including rarasaponins I (1, IC50=131microM) and II (2, 172microM), and raraoside A (4, 151microM) inhibited pancreatic lipase activity, which were stronger than that of theasaponin E(1) (270microM).

Caffeic and chlorogenic acids in Ilex paraguariensis extracts are the main inhibitors of AGE generation by methylglyoxal in model proteins

The present study concentrates on the evaluation of the anti-glycation effect of some bioactive substances present in yerba maté (Ilex paraguariensis): 5-caffeoylquinic acid, caffeic acid and a sapogenin (oleanolic acid). Bovine serum albumin and histones were incubated in the presence of methylglyoxal with or without the addition of 5-caffeoylquinic acid, caffeic acid and oleanolic acid. After the incubation period, advanced glycation end product (AGE) fluorescence spectra were performed and protein structural changes were evaluated by Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis. Chlorogenic acid, caffeic acid are the main substances responsible for the anti-glycation effect of maté tea.

Ascorbic acid oral treatment modifies lipolytic response and behavioural activity but not glucocorticoid metabolism in cafeteria diet-fed rats

AIM

To analyse the effects of vitamin C (VC), a potent dietary antioxidant, oral supplementation on body weight gain, behavioural activity, lipolytic response and glucocorticoid metabolism in the early stages of diet-induced overweight in rats.

METHODS

Food intake, locomotive activity and faecal corticosterone were assessed during the 14 day trial period. After 2 weeks, the animals were sacrificed and the body composition, biochemical markers and lipolytic response from isolated adipocytes from retroperitoneal white adipose tissue were examined.

RESULTS

The intake of a high-fat diet by rats induced a significant increase in body weight, adiposity and insulin resistance markers as well as a decrease in faecal corticosterone levels compared with standard diet-fed rats. Interestingly, the animals fed on the cafeteria diet showed a significant increase in the isoproterenol-induced lipolytic response in isolated adipocytes. Furthermore, this cafeteria-fed group showed a reduced locomotive behaviour than the control rats. On the other hand, oral VC supplementation in animals receiving the high-fat diet restored the cafeteria diet effect in some of the analysed variables such as final body weight and plasma insulin to control group levels. Remarkably, increases in locomotive behaviour and a significant decrease in the lipolytic response induced by isoproterenol on isolated adipocytes from animals treated with VC were observed.

CONCLUSION

This work demonstrates that an oral ascorbic acid supplementation has direct effects on behavioural activity and on adipocyte lipolysis in early obesity stages in rats, which could indicate a protective short-term role of this vitamin against adiposity induced by chronic high-fat diet consumption.

Ginsenosides chemistry, biosynthesis, analysis, and potential health effects

Ginsenosides are a special group of triterpenoid saponins that can be classified into two groups by the skeleton of their aglycones, namely dammarane- and oleanane-type. Ginsenosides are found nearly exclusively in Panax species (ginseng) and up to now more than 150 naturally occurring ginsenosides have been isolated from roots, leaves/stems, fruits, and/or flower heads of ginseng. Ginsenosides have been the target of a lot of research as they are believed to be the main active principles behind the claims of ginsengs efficacy. The potential health effects of ginsenosides that are discussed in this chapter include anticarcinogenic, immunomodulatory, anti-inflammatory, antiallergic, antiatherosclerotic, antihypertensive, and antidiabetic effects as well as antistress activity and effects on the central nervous system. Ginsensoides can be metabolized in the stomach (acid hydrolysis) and in the gastrointestinal tract (bacterial hydrolysis) or transformed to other ginsenosides by drying and steaming of ginseng to more bioavailable and bioactive ginsenosides. The metabolization and transformation of intact ginsenosides, which seems to play an important role for their potential health effects, are discussed. Qualitative and quantitative analytical techniques for the analysis of ginsenosides are important in relation to quality control of ginseng products and plant material and for the determination of the effects of processing of plant material as well as for the determination of the metabolism and bioavailability of ginsenosides. Analytical techniques for the analysis of ginsenosides that are described in this chapter are thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC) combined with various detectors, gas chromatography (GC), colorimetry, enzyme immunoassays (EIA), capillary electrophoresis (CE), nuclear magnetic resonance (NMR) spectroscopy, and spectrophotometric methods.

Comparison of hypolipidemic activity of synthetic gallic acid-linoleic acid ester with mixture of gallic acid and linoleic acid, gallic acid, and linoleic acid on high-fat diet induced obesity in C57BL/6 Cr Slc mice

Hyperlipidemia is the major risk factors of heart disease such as atherosclerosis, stroke, and death. In the present study, we studied the effect of gallic acid (GA), linoleic acid (LA), mixture of GA and LA (MGL), and chemically synthesized gallic acid-linoleic acid ester (octadeca-9,12-dienyl-3,4,5-trihydroxybenzoate, GLE) on the ability to ameliorate hyperlipidemia in C57BL/6 mice fed a high-fat diet (HFD). GLE, GA, LA, and MGL were mixed with HFD and the composition of the test compounds were 1% of the diet for 7 weeks. After 7 weeks, the average body weight of ND and GLE groups was lower than that of HFD group (P<0.05). The liver weight of mice decreased (P<0.05) in all treatment groups relative to HFD fed group. The plasma lipids such as triglyceride and LDL-cholesterol were found to be decreased (P<0.05) in GLE, GA, LA, and MGL fed mice when compared to that of HFD fed mice. But high-density lipoprotein (HDL) cholesterol increased (P<0.05) in HFD and GLE fed mice when compared to that of ND fed mice. The hepatic accumulation of fat droplets of GA, LA, GLE, and MGL group showed considerably lower than that of HFD group. Adipose histology showed that GLE supplementation was found to be more effective in decreasing the size of adipocyte relative to those of other treatment groups. In conclusion, the supplementation of synthetic GLE from gallic acid and linoleic acid ester may have a potential hypolipidemic effect on mice fed high-fat diet. Further studies are required to prove GLE as a hypolipidemic agent.

Plants popularly used for loosing weight purposes in Porto Alegre, South Brazil

In this study, 14 herbalists (herb sellers) were interviewed about popular use of plants with weight loss purpose in Porto Alegre, a South Brazil city. For all identified species, scientific data were reviewed aiming to establish a correlation between popular use and biological properties. Seventy-eight samples were reported as having weigh loss properties. These samples come from 23 species and Asteraceae encompasses the greatest number of representatives. The greatest number of herbalist's citations was Baccharis articulata. The majority of plants have traditional use in Brazil but none is explicitly cited for loosing weight purposes. The pharmacological data are mainly from animal and in vitro studies and do not straight related to obesity. Only Ilex paraguariensis presents clinical data of efficacy in the treatment of obesity. Seven species present pre-clinical data that indicate a potential role in the control of certain conditions which are associated with obesity, such as hyperlipidemia (Campomanesia xanthocarpa, Cuphea carthagenensis, Cynara scolymus, Hibiscus sabdariffa, Ilex paraguariensis) and high levels of blood glucose (Achyrocline satureioides, Baccharis trimera, Campomanesia xanthocarpa). In conclusion, scientific data found are insufficient to guarantee the efficacy and safety of these plants for treating obesity. However, some of them present activities which could be useful to treat certain obesity comorbidities and deserve further studies.

Hypolipemic effect of water extracts of Picrorrhiza kurroa in high fat diet treated mouse

A hypolipemic effect of the water extract of Picrorrhiza kurroa (PR) was observed in a high fat diet feeding hyperlipemic mouse at doses of 50, 100 and 200 mg/kg, orally, once a day for 12 weeks. Liver weight, serum aspartate transferase (AST), alanine transferase (ALT), low density lipoprotein (LDL), triglyceride and total cholesterol levels were significantly reduced by the treatment. On the contrary, serum HDL level seems not affected by P. kurroa water extract.

Ginsenoside Rb1 promotes adipogenesis in 3T3-L1 cells by enhancing PPARgamma2 and C/EBPalpha gene expression

Evidence has accumulated that ginseng and its main active constituents, ginsenosides, possess anti-diabetic and insulin-sensitizing properties which may be partly realized by regulating adipocyte development and functions. In the present study, we explored the effect of ginsenoside Rb(1), the most abundant ginsenoside in ginseng root, on adipogenesis of 3T3-L1 cells. We found that with standard differentiation inducers, ginsenoside Rb(1) facilitated adipogenesis of 3T3-L1 preadipocytes in a dose-dependent manner; 10 microM Rb(1) increased lipid accumulation by about 56%. Treatment of differentiating adipocytes with 10 microM Rb(1) increased the expression of mRNA and protein of PPARgamma(2) and C/EBPalpha, as well as mRNA of ap2, one of their target genes. After the treatment of differentiating adipocytes with Rb(1), basal and insulin-mediated glucose uptake was significantly augmented, accompanied by the up-regulation of mRNA and protein level of GLUT4, but not of GLUT1. In addition, ginsenoside Rb(1) also inhibited the proliferation of preconfluent 3T3-L1 preadipocytes. Our data indicate that anti-diabetic and insulin-sensitizing activities of ginsenosides, at least in part, are involved in the enhancing effect on PPARgamma2 and C/EBPalpha expression, hence promoting adipogenesis.

Hypolipemic effect of water extracts of Picrorrhiza rhizoma in PX-407 induced hyperlipemic ICR mouse model with hepatoprotective effects: a prevention study

The preventive hypolipemic effect of water extract of Picrorrhiza rhizoma (PR) was observed in Poloxamer (PX)-407 induced hyperlipemic mice with their hepatoprotective effects. Doses of 50, 100 and 200 mg/kg of PR extracts were given orally once a day for 12 weeks initiated with intraperitoneal injection of PX-407 (0.5 g/kg), and changes in body weight and gains, liver weight, serum aspartate transferase (AST) and alanine transferase (ALT) levels were monitored with serum low density lipoprotein (LDL), high density lipoprotein (HDL), triglyceride and total cholesterol levels. The efficacy of PX-407 was compared to that of 10mg/kg of simvastatin (SIMVA). No meaningful changes in the body weight were detected in all dosing groups compared to that of vehicle control group. Dramatic decrease of both absolute and relative liver weight was dose-dependently observed in all PR extracts dosing groups compared to that of vehicle control group. The serum AST and ALT levels were significantly and dose-dependently decreased in PR extracts dosing groups. However, slight increase of liver weight, serum AST and ALT levels were detected in SIMVA-dosing groups. The serum LDL, triglyceride and total cholesterol levels were dose-dependently decreased in PR extracts dosing groups and SIMVA-dosing group compared to that of vehicle control group, respectively. The serum HDL levels were slightly but dose-dependently increased in PR extracts dosing groups compared to that in vehicle control group, respectively. However, the efficacy on the serum lipid levels of PR extracts was lower than that of SIMVA-about 200 mg/kg of PR extracts which showed similar effect compared to that of SIMVA 10mg/kg. On the basis of these results, it is concluded that water extract of PR has a relatively good favorable preventive effect on the PX-407 inducing hyperlipemia with favorable hepatoprotective effect.