Antihyperglycemic Effects of Salvia polystachya Cav. and Its Terpenoids: α-Glucosidase and SGLT1 Inhibitors.

The antihyperglycemic activity of ethanolic extract from Salvia polystachya (EESpS) and its products was evaluated using in vivo, ex vivo and in silico assays; additionally, an acute toxicity assay was evaluated. EESpS was classified as a nontoxic class 5 drug. EESpS, ethyl acetate fraction (EtOAcFr), secondary-6-fraction (SeFr6), ursolic acid (UA), and oleanolic acid (OA) reduced the hyperglycemia in DM2 mice. α-glucosidase inhibition was evaluated with oral sucrose and starch tolerance tests (OSuTT and OStTT), an intestinal sucrose hydrolysis (ISH) assay and molecular docking studies using acarbose as control. SGLT1 inhibition was evaluated with oral glucose and galactose tolerance tests (OGTT and OGaTT), an intestinal glucose absorption (IGA) assay and molecular docking studies using canagliflozin as the control. During the carbohydrate tolerance tests, all the treatments reduced the postprandial peak, similar to the control drugs. During the ISH, IC50 values of 739.9 and 726.3 µM for UA and OA, respectively, were calculated. During the IGA, IC50 values of 966.6 and 849.3 for UA, OA respectively, were calculated. Finally, during the molecular docking studies, UA and OA showed ∆G values of -6.41 and -5.48 kcal/mol-1, respectively, on α-glucosidase enzymes. During SGLT1, UA and OA showed ∆G values of -10.55 and -9.65, respectively.

Glycine is a competitive antagonist of the TNF receptor mediating the expression of inflammatory cytokines in 3T3-L1 adipocytes.

OBJECTIVE: To determine the involvement of TNF-α and glycine receptors in the inhibition of pro-inflammatory adipokines in 3T3-L1 cells. METHODS: RT-PCR evidenced glycine receptors in 3T3-L1 adipocytes. 3T3-L1 cells were transfected with siRNA for the glycine (Glrb) and TNF1a (Tnfrsf1a) receptors and confirmed by confocal microscopy. Transfected cells were treated with glycine (10 mM). The expressions of TNF-α and IL-6 mRNA were measured by qRT-PCR, while concentrations were quantified by ELISA. RESULTS: Glycine decreased the expression and concentration of TNF-α and IL-6; this effect did not occur in the absence of TNF-α receptor due to siRNA. In contrast, glycine produced only slight changes in the expression of TNF-α and IL-6 in the absence of the glycine receptor due to siRNA. A docking analysis confirmed the possibility of binding glycine to the TNF-α1a receptor. CONCLUSION: These findings support the idea that glycine could partially inhibit the binding of TNF-α to its receptor and provide clues about the mechanisms by which glycine inhibits the secretion of pro-inflammatory adipokines in adipocytes through the TNF-α receptor.

Oleanolic acid induces a dual agonist action on PPARγ/α and GLUT4 translocation: A pentacyclic triterpene for dyslipidemia and type 2 diabetes.

Type 2 diabetes (T2D) is a metabolic disease characterized by defects in glycemia regulation. This disease is associated with alterations in insulin action and lipid metabolism, generating hyperglycemia and dyslipidemias. Currently, it is necessary to develop new or known drugs that promote the sensitization of insulin action. Thus, activation of peroxisome proliferator-activated receptors (PPARs) is probably the key to doing this. PPARs participate in maintaining an energetic balance between storage and the expenditure of energy. The activation of PPARγ produces the storage of energy, mainly as glycogen and fat. Meanwhile, PPARα activation promotes lipid degradation. Oleanolic acid (OA), a pentacyclic triterpenoid of numerous edible and medicinal plants, decreases hyperglycemia and lipid accumulation. However, the effects on PPARs and their regulated genes are unknown. Our aim was to determine the effects of OA on PPAR γ/α expression and their regulated genes (adiponectin, type 4 glucose transporter, fatty acid transport protein, and long-chain acyl-CoA synthetase) in C2C12 myoblasts by RT-PCR, Western blot, GLUT-4 translocation, and lipid storage in 3T3-L1 adipocytes. In C2C12 myoblasts, OA increased the expression of mRNA in both PPARγ/α and their regulated genes; also, PPARγ, GLUT-4, and FATP-1 protein expression increased, as well as GLUT-4 translocation. In 3T3-L1, OA increased the expression of mRNA in both PPARγ/α and maintained lipid storage unchanged. In conclusion, OA exhibited a dual action on PPARγ/α, which might explain in part its antihyperglycemic effect. This compound represents an alternative for designing novel therapeutic strategies in the control of T2D.

The Tillandsia genus: history, uses, chemistry, and biological activity / El género Tillandsia: historia, usos, química y actividad biológica

Tillandsia L. genus comprises 649 species, with different uses at different times. T. usneoides L. uses are reported since the late- archaic and pre-Columbian cultures. In XIX-XX centuries, T. usneoides was used in some manufactured products, as polish and packing fruit. Tillandsia has a favorable reputation as medicine: for leucorrhea, rheumatism, ulcers, hemorrhoid treatment, as an anti-diabetic remedy, emetic, analgesic, purgative, contraceptive, antispasmodic and diuretic. Tillandsia chemical composition includes cycloartane triterpenes and hydroxy-flavonoids, which are present in at least 24 species. Several extracts and compounds from Tillandsia spp. have been reported with pharmacological actions, as anti-neoplasia, hypolipidemic, antifungal, anti-HSV-1, hypoglycemic and microbicide. This review communicates the economic importance, ethnobotany, chemistry composition and biological activities of the Tillandsia genus, and analyze its biological and economic perspective. Tillandsia genus has cultural, economic and pharmacological relevance, with a high potential in many essential aspects of the modern society.

El género Tillandsia L. comprende 649 especies, con diferentes usos en diferentes épocas. T. usneoides L. se han reportado desde el arcáico tardío hasta las culturas precolombinas. En los siglos XIX-XX, T. usneoides se usó en productos manufacturados: como abrasivo y embalaje de fruta. Como medicina tradicional, el género Tillandsia se reporta para leucorrea, reumatismo, úlceras, hemorroides, remedio antidiabético, emético, analgésico, purgante, anticonceptivo, antiespasmódico y diurético. Su composición química incluye triterpenos de tipo ciclo-artano e hidroxi-flavonoides, presentes en al menos 24 especies. Los extractos y compuestos del género Tillandsia se han reportado con propiedades antineoplásicas, hipolipidémicas, antifúngicas, anti-HSV-1, hipoglucemiantes y microbicidas. Esta revisión comunica la importancia económica, etnobotánica, composición química y las actividades biológicas del género Tillandsia, y analiza su perspectiva biológica y potencial económica. Tillandsia tiene importancia cultural, económica y farmacológica, con gran potencial en muchos aspectos esenciales de la sociedad moderna.

Triterpenoids from Hibiscus sabdariffa L. with PPARδ/γ Dual Agonist Action: In Vivo, In Vitro and In Silico Studies.

Hibiscus sabdariffa is a medicinal plant consumed as a diuretic and anti-obesity remedy. Several pharmacological studies have shown its beneficial effects in metabolism. Peroxisome proliferator-activated receptors δ and γ may play a role in the actions of H. sabdariffa. These nuclear receptors regulate lipid and glucose metabolism and are therapeutic targets for type 2 diabetes. This research aimed to perform a phytochemical study guided by a bioassay from H. sabdariffa to identify compounds with peroxisome proliferator-activated receptor δ and peroxisome proliferator-activated receptor γ agonist activity, supported by messenger ribonucleic acid expression, molecular docking, lipid accumulation, and an antihyperglycemic effect. An oral glucose tolerance test in mice with the aqueous extract of H. sabdariffa and the dichloromethane extract of H. sabdariffa was performed. The dichloromethane extract of H. sabdariffa exhibited an antihyperglycemic effect. The dichloromethane extract of H. sabdariffa was fractioned, and four fractions were evaluated in 3T3-L1 adipocytes on peroxisome proliferator-activated receptor δ, peroxisome proliferator-activated receptor γ, fatty acid transporter protein, and glucose transporter type 4 messenger ribonucleic acid expression. Fraction F3 exhibited peroxisome proliferator-activated receptor δ/γ dual agonist activity, and a further fractionation yielded two subfractions, F3-1 and F3-2, which also increased peroxisome proliferator-activated receptor δ and peroxisome proliferator-activated receptor γ expression. Subfractions were analyzed by GC/MS. The main compounds identified in F3-1 were linoleic acid, oleic acid, and palmitic acid, while in F3-2, the main compounds identified were α-amyrin and lupeol. These molecules were subjected to molecular docking analysis. α-Amyrin and lupeol showed the highest affinity. Moreover, both produced an increase in peroxisome proliferator-activated receptor δ, peroxisome proliferator-activated receptor γ, fatty acid transporter protein, and glucose transporter type 4 expression. Additionally, α-amyrin and lupeol decreased lipid accumulation in 3T3-L1 adipocytes and blood glucose in mice. Until now, α-amyrin and lupeol have not been reported with activity on peroxisome proliferator-activated receptors. This study provides evidence that α-amyrin and lupeol possess antidiabetic effects through a peroxisome proliferator-activated receptor δ/γ dual agonist action.

Discovery of new dual PPARγ-GPR40 agonists with robust antidiabetic activity: Design, synthesis and in combo drug evaluation.

The design of compounds 1 and 2 was based on the similar scaffold of pharmacophoric groups for PPARγ and GPR40 agonists. In order to find new compounds with improved biological activity, the current manuscript describes a new dual PPARγ-GPR40 agonist. We synthesized two compounds, which were prepared following a multistep synthetic route, and the relative mRNA expression levels of PPARγ, GLUT4, and GPR40 were quantified in cell culture, as well as insulin secretion and [Ca2+] intracellular levels. Compound 1 showed a 7-times increase in the mRNA expression of PPARγ, which in turn enhanced the expression levels of GLUT4 respect to control and pioglitazone. It also showed an increase of 2-fold in the [Ca2+]i level allowing an increment on insulin release, being as active as the positive control (glibenclamide), causing also an increase of 2-fold in mRNA expression of GPR40. Furthermore, the compound 2 showed lower activity than the compound 1. The ester of 1 showed antidiabetic activity at a 50mg/kg single dose in streptozotocin-nicotinamide-induced diabetic mice model. In addition, we achieved a molecular docking study of compound 1 on PPARγ and GPR40 receptors, showing a great affinity for both targets. We observed important polar interactions between the carboxylic group and main residues into the binding pocket. Therefore, the compound 1 has a potential for the development of antidiabetic agents with newfangled dual action.

Fermented blueberry juice extract and its specific fractions have an anti-adipogenic effect in 3 T3-L1 cells.

BACKGROUND: Obesity and Type 2 diabetes have reached epidemic status worldwide. Wild lowbush blueberry (Vaccinium angustifolium Aiton) is a plant of the North American Aboriginal traditional pharmacopeia with antidiabetic potential, especially when it is fermented with Serratia vaccinii. METHODS: A phytochemical fractionation scheme was used to identify potential bioactive compounds as confirmed by HPLC retention times and UV-Vis spectra. 3 T3-L1 cells were differentiated for 7 days with either Normal Blueberry Extract (NBE), Fermented Blueberry Extract (FBE/F1), seven fractions and four pure compounds. Triglyceride content was measured. Examination of selected intracellular signalling components (p-Akt, p-AMPK) and transcriptional factors (SREBP-1c and PPARγ) was carried out by Western blot analysis. RESULTS: The inhibitory effect of FBE/F1 on adipocyte triglyceride accumulation was attributed to total phenolic (F2) and chlorogenic acid enriched (F3-2) fractions that both inhibited by 75%. Pure compounds catechol (CAT) and chlorogenic acid (CA) also inhibited adipogenesis by 70%. Treatment with NBE, F1, F3-2, CAT and CA decreased p-AKT, whereas p-AMPK tended to increase with F1. The expression of SREBP1-c was not significantly modulated. In contrast, PPARγ decreased in all experimental groups that inhibited adipogenesis. CONCLUSIONS: These results demonstrate that fermented blueberry extract contains compounds with anti-adipogenic activity, which can serve to standardize nutraceutical preparations from fermented blueberry juice and to develop novel compounds with anti-obesity properties.

Biochemical alterations during the obese-aging process in female and male monosodium glutamate (MSG)-treated mice.

Obesity, from children to the elderly, has increased in the world at an alarming rate over the past three decades, implying long-term detrimental consequences for individual's health. Obesity and aging are known to be risk factors for metabolic disorder development, insulin resistance and inflammation, but their relationship is not fully understood. Prevention and appropriate therapies for metabolic disorders and physical disabilities in older adults have become a major public health challenge. Hence, the aim of this study was to evaluate inflammation markers, biochemical parameters and glucose homeostasis during the obese-aging process, to understand the relationship between obesity and health span during the lifetime. In order to do this, the monosodium glutamate (MSG) obesity mice model was used, and data were evaluated at 4, 8, 12, 16 and 20 months in both female and male mice. Our results showed that obesity was a major factor contributing to premature alterations in MSG-treated mice metabolism; however, at older ages, obesity effects were attenuated and MSG-mice became more similar to normal mice. At a younger age (four months old), the Lee index, triglycerides, total cholesterol, TNF-α and transaminases levels increased; while adiponectin decreased and glucose tolerance and insulin sensitivity levels were remarkably altered. However, from 16 months old-on, the Lee index and TNF-α levels diminished significantly, while adiponectin increased, and glucose and insulin homeostasis was recovered. In summary, MSG-treated obese mice showed metabolic changes and differential susceptibility by gender throughout life and during the aging process. Understanding metabolic differences between genders during the lifespan will allow the discovery of specific preventive treatment strategies for chronic diseases and functional decline.

Composition and Antidiarrheal Activity of Bidens odorata Cav.

The antidiarrheal effects of chloroform, methanol, and aqueous extracts of Bidens odorata Cav. were investigated at doses of 200 mg/kg on castor-oil-induced diarrhea. The chloroform extract of B. odorata (CBO) reduced diarrhea by 72.72%. The effect of CBO was evaluated on mice with diarrhea induced by castor oil, MgSO4, arachidonic acid, or prostaglandin E2. CBO inhibited the contraction induced by carbachol chloride on ileum (100 µg/mL) and intestinal transit (200 mg/kg) in Wistar rats. The active fraction of CBO (F4) at doses of 100 mg/kg inhibited the diarrhea induced by castor oil (90.1%) or arachidonic acid (72.9%) but did not inhibit the diarrhea induced by PGE2. The active fraction of F4 (FR5) only was tested on diarrhea induced with castor oil and inhibited this diarrhea by 92.1%. The compositions of F4 and FR5 were determined by GC-MS, and oleic, palmitic, linoleic, and stearic acids were found. F4 and a mixture of the four fatty acids inhibited diarrhea at doses of 100 mg/kg (90.1% and 70.6%, resp.). The results of this study show that B. odorata has antidiarrheal effects, as is claimed by folk medicine, and could possibly be used for the production of a phytomedicine.

Discovery of thiazolidine-2,4-dione/biphenylcarbonitrile hybrid as dual PPAR α/γ modulator with antidiabetic effect: in vitro, in silico and in vivo approaches.

A small series of thiazolidine-2,4-dione and barbituric acid derivatives 1-4 was prepared using a short synthetic route, and all compounds were characterized by elemental analysis, mass spectrometry, and NMR ((1)H, (13)C) spectroscopy. Their in vitro relative expression of peroxisome proliferator-activated receptor α and peroxisome proliferator-activated receptor γ was evaluated. Compound 1 showed an increase in the mRNA expression of both peroxisome proliferator-activated receptor isoforms, as well as the GLUT-4 levels. The antidiabetic activity of compound 1 was determined at 50 mg/kg single dose using a non-insulin-dependent diabetes mellitus rat model. The results indicated a significant decrease in plasma glucose levels. Additionally, we performed a molecular docking of compound 1 into the ligand binding pocket of peroxisome proliferator-activated receptor α and peroxisome proliferator-activated receptor γ. In these binding models, compound 1 may bind into the active site of both isoforms showing important short contacts with the peroxisome proliferator-activated receptor γ residues: Tyr 473, His 449, Ser 289, His 323; and peroxisome proliferator-activated receptor α residues: Tyr 464, His 440, Ser 280 and Tyr 314.

Hypoglycemic Activity of Aqueous Extracts from Catharanthus roseus.

Introduction. Catharanthus roseus (L.) is used in some countries to treat diabetes. The aim of this study was to evaluate the hypoglycemic activity of extracts from the flower, leaf, stem, and root in normal and alloxan-induced diabetic mice. Methods. Roots, leaves, flowers, and stems were separated to obtain organic and aqueous extracts. The blood glucose lowering activity of these extracts was determinate in healthy and alloxan-induced (75 mg/Kg) diabetic mice, after intraperitoneal administration (250 mg/Kg body weight). Blood samples were obtained and blood glucose levels were analyzed employing a glucometer. The data were statistically compared by ANOVA. The most active extract was fractioned. Phytochemical screen and chromatographic studies were also done. Results. The aqueous extracts from C. roseus reduced the blood glucose of both healthy and diabetic mice. The aqueous stem extract (250 mg/Kg) and its alkaloid-free fraction (300 mg/Kg) significantly (P < 0.05) reduced blood glucose in diabetic mice by 52.90 and 51.21%. Their hypoglycemic activity was comparable to tolbutamide (58.1%, P < 0.05). Conclusions. The best hypoglycemic activity was presented for the aqueous extracts and by alkaloid-free stem aqueous fraction. This fraction is formed by three polyphenols compounds.

Glycine suppresses TNF-α-induced activation of NF-κB in differentiated 3T3-L1 adipocytes.

Glycine strongly reduces the serum levels of pro-inflammatory cytokines and increases the levels of anti-inflammatory cytokines. Recently, glycine has been shown to decrease the expression and secretion of pro-inflammatory adipokines in monosodium glutamate-induced obese (MSG/Ob) mice. It has been postulated that these effects may be explained by a reduction in nuclear factor kappa B (NF-κB) activation. NF-κB is a transcription factor, which is crucial to the inflammatory response. Hasegawa et al. (2011 and 2012) recently reported a glycine-dependent reduction in NF-κB levels. Here, we have investigated the role of glycine in the regulation of NF-κB in differentiated 3T3-L1 adipocytes. The results revealed that pretreatment with glycine interfered with the activation of NF-κB, which has been shown to be stimulated by tumor necrosis factor-alpha (TNF-α). Glycine alone stimulated NF-κB activation in an unusual way such that the inhibitor κB-ß (IκB-ß) degradation was more significant than that of the inhibitor κB-α (IκB-α) and led to NF-κB complexes comprised of p50 and p65 subunits; IκB-ε degradation did not affect by glycine. These findings suggest that glycine could be used as an alternative treatment for chronic inflammation, which is a hallmark of obesity and other comorbidities, and is characterized by an elevated production of pro-inflammatory cytokines.

Monosodium glutamate neonatal intoxication associated with obesity in adult stage is characterized by chronic inflammation and increased mRNA expression of peroxisome proliferator-activated receptors in mice.

The monosodium glutamate (MSG) neonatal administration in mice provides a model of obesity with impaired glucose tolerance (IGT) and insulin resistance. However, the inflammatory profile of cytokines produced from fat tissue and its relationship to the metabolic dysfunction induced by MSG have not yet been revealed. The aim of this study was to establish the inflammatory profile attributed to MSG by measuring the expression of adipokines in visceral fat and serum of 19-week-old mice as well as the peroxisome proliferator-activated receptors alpha and gamma (PPARα and γ). Some metabolic and biochemical parameters were also quantified. The MSG increased mRNA expression of interleukin-6 (IL-6), tumour necrosis factor-alpha (TNFα), resistin and leptin, but adiponectin did not exhibit any changes. In addition, impaired glucose tolerance, increased levels of insulin, resistin and leptin were observed in serum. Both PPARα and PPARγ were activated in MSG-induced obese mice, which might explain its inflammatory profile. However, liver transaminases were severely depressed, indicating that MSG may also induce liver injury, contributing to inflammation. The MSG neonatal neuro-intoxication in mice may thus provide a model of obesity and inflammation characterized by the dual activation of PPARα and PPARγ, which might offer new insights into the mechanism of inflammatory diabetes in obesity leading to steatohepatitis, as well as a suitable model to study the role of new therapeutic agents to prevent or reduce insulin resistance, the inflammatory state and liver steatosis.

Effect of Hibiscus sabdariffa on obesity in MSG mice.

The aim of the present investigation was determine whether a standardized Hibiscus sabdariffa calyces aqueous extract has an effect on body weight in an obese animal model induced by the administration of monosodium glutamate. Hibiscus sabdariffa aqueous extract, containing 33.64 mg of total anthocyanins per each 120 mg of extract, was orally administered (120 mg/kg/day) for 60 days to healthy and obese mice, and body weight gain, food and liquid intake, aspartate aminotransferase (AST), alanine aminotransferase (ALT), cholesterol, and triglycerides levels were measured. Hibiscus sabdariffa administration significantly reduced body weight gain in obese mice and increased liquid intake in healthy and obese mice. ALT levels were significantly increased on the 15th and 45th days in obese mice, but AST levels did not show significant changes. Mortality was not observed in the Hibiscus sabdariffa treated groups. Triglycerides and cholesterol levels showed non-significant reductions in animals treated with Hibiscus sabdariffa. Our data confirm the anti-obesity effect of Hibiscus sabdariffa reported by the Mexican population.

Monoglycerides and fatty acids from Ibervillea sonorae root: isolation and hypoglycemic activity.

Eleven monoglycerides (MG), 1-monopalmitin (1), glyceryl 1-monomargarate (2), 1-monostearin (3), glyceryl 1-monononadecylate ( 4), glyceryl 1-monoarachidate (5), glyceryl 1-monobehenate (6), glyceryl 1-monotricosanoate (7), glyceryl 1-monotetracosanoate (8), glyceryl 1-monopentacosanoate (9), glyceryl 1-monohexacosanoate (10) and glyceryl 1-monooctacosanoate (11), together with five fatty acids (FA), lauric acid (12), myristic acid (13), pentadecanoic acid (14), palmitic acid (15) and stearic acid (16) were isolated of the root of IBERVILLEA SONORAE Greene (Cucurbitaceae). Their structures were determined by spectroscopic and chemical methods as well as GC-MS analysis. The hypoglycemic activity of the dichloromethane (DCM) extract, of fractions (F1-F10 and SF1-SF5), of monoglycerides (MG) and of fatty acids (FA) mixtures obtained of the root from I. SONORAE was evaluated in normoglycemic and alloxan-induced diabetic mice. The results showed that by intraperitoneal administration the DCM extract (300 mg/kg), F9 (300 mg/kg) and SF1 (150 mg/kg) significantly reduced glucose levels in both models. For fraction SF1, the hypoglycemic activity was more pronounced than that of tolbutamide (150 mg/kg) used as control. However, neither MG (75 mg/kg) nor FA (75 mg/kg) mixtures isolated from SF1 exhibited a significant hypoglycemic effect. However, when MG and FA were combined in equal proportions (75 mg: 75 mg/kg), their effect was comparable to that of SF1. The observed activity for the DCM extract, F9, SF1 and the MG-FA mixture provides additional support for the popular use of this plant in the treatment of diabetes mellitus in Mexican traditional medicine.

Effect of a polyphenol-rich extract from Aloe vera gel on experimentally induced insulin resistance in mice.

Insulin resistance, which precedes type 2 diabetes mellitus (T2DM), is a widespread pathology associated with the metabolic syndrome, myocardial ischemia, and hypertension. Finding an adequate treatment for this pathology is an important goal in medicine. The purpose of the present research was to investigate the effect of an extract from Aloe vera gel containing a high concentration of polyphenols on experimentally induced insulin resistance in mice. A polyphenol-rich Aloe vera extract (350 mg/kg) with known concentrations of aloin (181.7 mg/g) and aloe-emodin (3.6 mg/g) was administered orally for a period of 4 weeks to insulin resistant ICR mice. Pioglitazone (50 mg/kg) and bi-distilled water were used as positive and negative controls respectively. Body weight, food intake, and plasma concentrations of insulin and glucose were measured and insulin tolerance tests were performed. The insulin resistance value was calculated using the homeostasis model assessment for insulin resistance (HOMA-IR) formula. Results showed that the polyphenol-rich extract from Aloe vera was able to decrease significantly both body weight (p < 0.008) and blood glucose levels (p < 0.005) and to protect animals against unfavorable results on HOMA-IR, which was observed in the negative control group. The highest glucose levels during the insulin tolerance curve test were in the negative control group when compared to the Aloe vera extract and pioglitazone treated mice (p < 0.05). In conclusion, Aloe vera gel could be effective for the control of insulin resistance.