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Insulin secretion and GLUT4 expression are two critical events in glucose regulation. The receptors G-protein-coupled receptor 40 (GPR40) and peroxisome proliferator-activated receptor-gamma (PPAR γ ) modulate these processes, and they represent potential therapeutic targets for new antidiabetic agent's design. Cucurbita ficifolia fruit is used in traditional medicine for diabetes control. Previous studies demonstrated several effects: a hypoglycemic effect mediated by an insulin secretagogue action, antihyperglycemic effect, and promoting liver glycogen storage. Anti-inflammatory and antioxidant effects were also reported. Moreover, some of its phytochemicals have been described, including d-chiro-inositol. However, to understand these effects integrally, other active principles should be investigated. The aim was to perform a chemical fractionation guided by bioassay to isolate and identify other compounds from C. ficifolia fruit that explain its hypoglycemic action as insulin secretagogue, its antihyperglycemic effect by PPAR γ activation, and on liver glycogen storage. Three different preparations of C. ficifolia were tested in vivo . Ethyl acetate fraction derived from aqueous extract showed antihyperglycemic effect in an oral glucose tolerance test and was further fractioned. The insulin secretagogue action was tested in RINm5F cells. For the PPAR γ activation, C2C12 myocytes were treated with the fractions, and GLUT4 mRNA expression was measured. Chemical fractionation resulted in the isolation and identification of β -sitosterol and 4-hydroxybenzoic acid (4-HBA), which increased insulin secretion, GLUT4, PPAR γ , and adiponectin mRNA expression, in addition to an increase in glycogen storage. 4-HBA exhibited an antihyperglycemic effect, while β -sitosterol showed hypoglycemic effect, confirming the wide antidiabetic related results we found in our in vitro models. An in silico study revealed that 4-HBA and β -sitosterol have potential as dual agonists on PPAR γ and GPR40 receptors. Both compounds should be considered in the development of new antidiabetic drug development.

This work presents the synthesis of two hybrid compounds (1 and 2) with thiazolidine-2,4-dione structure as a central scaffold which were further screened in combo (in vitro as PTP-1B inhibitors, in vivo antihyperglycemic activity, in silico toxicological profile and molecular docking). Compound 1 was tested in the enzymatic assay showing an IC 50 = 9.6 ± 0.5 μM and compound 2 showed about a 50% of inhibition of PTP-1B at 20 μM. Therefore, compound 1 was chosen to test its antihyperglycemic effect in a rat model for non-insulin-dependent diabetes mellitus (NIDDM), which was determined at 50 mg/kg in a single dose. The results indicated that compound showed a significant decrease of plasma glucose levels that reached 34%, after a 7 h post-administration. Molecular docking was employed to study the inhibitory properties of thiazolidine-2,4-dione derivatives against Protein Tyrosine Phosphatase 1B (PDB ID: 1c83). Concerning to the two binding sites in this enzyme (sites A and B), compound 1 has shown the best docking score, which indicates the highest affinity. Finally, compounds 1 and 2 have demonstrated an in silico satisfactory pharmacokinetic profile. This shows that it could be a very good candidate or leader for new series of compounds with this central scaffold., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

Hit, Lead & Candidate Discovery Protein tyrosine phosphatase 1B (PTP-1B) has attracted interest as a novel target for the treatment of type 2 diabetes, this because its role in the insulin-signaling pathway as a negative regulator. Thus, the aim of current work was to obtain seven ursolic acid derivatives as potential antidiabetic agents with PTP-1B inhibition as main mechanism of action. Furthermore, derivatives 1-7 were submitted in vitro to enzymatic PTP-1B inhibition being 3, 5, and 7 the most active compounds (IC 50  = 5.6, 4.7, and 4.6 μM, respectively). In addition, results were corroborated with in silico docking studies with PTP-1B orthosteric site A and extended binding site B, showed that 3 had polar and Van der Waals interactions in both sites with Lys120, Tyr46, Ser216, Ala217, Ile219, Asp181, Phe182, Gln262, Val49, Met258, and Gly259, showing a docking score value of -7.48 Kcal/mol, being more specific for site A. Moreover, compound 7 showed polar interaction with Gln262 and Van der Waals interactions with Ala217, Phe182, Ile219, Arg45, Tyr46, Arg47, Asp48, and Val49 with a predictive docking score of -6.43 kcal/mol, suggesting that the potential binding site could be localized in the site B adjacent to the catalytic site A. Finally, derivatives 2 and 7 (50 mg/kg) were selected to establish their in vivo antidiabetic effect using a noninsulin-dependent diabetes mice model, showing significant blood glucose lowering compared with control group (p < .05)., (© 2018 Wiley Periodicals, Inc.)

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 [Ca 2+ ] 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 [Ca 2+ ] 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., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

Flavonoids from medicinal plants have been used in traditional medicine to treat a variety of prevalent diseases. Flavones activate the signaling pathways promoting fuel metabolism and insulin sensitizing in hepatocytes and adipocytes, which suggests that flavones may have the potential to exert in vivo antidiabetic and antihyperlipidemic effects. Thus, the aim of the current study was to determine the antidiabetic, antihyperlipidemic and anti-inflammatory effects of tilianin in diabetic rats. Also, to understand the mechanism involved using in vitro 3T3-L1 cells and tissues from experimental animals treated with test samples through molecular profile studies. Non insulin-dependent diabetic mellitus (NIDDM) rats were treated over a short period (for 10 days) with 60mg/Kg/day of tilianin. After treatment, a biochemical blood profile was determined. Also, adipose and thoracic aortic tissues were used to determine pro-inflammatory profile, adiponectin and adhesion molecules by real-time PCR. In 3T3-L1 cells pretreated with tilianin (10μM), PPARα, PPARγ, GLUT4, FATP-1 and ACSL-1 mRNA expression were measured. In order to explain the potential PPARα interaction with tilianin, a docking study with PPARα was carried out. Thus, intragastric administration of tilianin and metformin induced a decrease in plasma glucose (GLU) in diabetic rats on day 6, and remained significantly lower until the end of the treatment; also blood triacylglycerides (TAG) and cholesterol (CHOL) (p<0.05) were diminished. Moreover, IL-1β and IL-18 expression was significantly decreased in adipose tissue (p<0.05); meanwhile adiponectin was significantly overexpressed (p<0.05). Besides, ICAM-1 expression was significantly reduced in aortic tissue (p<0.05). In 3T3-L1 cells it was found that tilianin increased PPARα and ACSL1 mRNA levels (p<0.05). Finally, tilianin docking studies with PPARα showed polar interactions with Glu269, Tyr314, His 440 and Tyr464 residues. In conclusion, short-term tilianin treatment might exert its antidiabetic and antihyperlipidemic effect by modulating a pro-inflammatory profile, and increasing adiponectin expression. In addition, our results suggest the possible interaction of tilianin with PPARα., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)

Six derivatives (1-6) of moronic acid were semi-synthesized and their in vitro protein tyrosine phosphatase 1B (PTP-1B) inhibition activity assessed. Derivatives 2 (IC50=10.8 ± 0.5 μM) and 6 (IC50=7.5 ± 0.1 μM) displayed the most potent inhibitory activity. Therefore, they (50mg/Kg) were tested for their antidiabetic effect in vivo using a non-insulin dependent diabetes mellitus rat model. The results indicated that they decrease plasma glucose levels during all the experiment (p <0.05). Docking analysis of 2 and 6 with PTP-1B orthosteric site A and allosteric site B, showed that 2 had polar and Van der Waals interactions in both sites with Val49, Gln262, Met258, Phe182, Ala217, Ile219 and Gly259, displaying more affinity for site A. Compound 6 showed polar interaction with Gln262 and Van der Waals with Val49, Ile219, Gly259, Arg254, Ala27, Phe52, Met258, Asp48 and Phe182, suggesting that the potential binding site is localized in site B, close to the catalytic site A. Therefore, derivatives 2 and 6 have potential for the development of antidiabetic agents., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Compound {4-[({4-[(Z)-(2,4-dioxo-1,3-thiazolidin-5-ylidene)methyl]phenoxy}acetyl)amino]phenoxy}acetic acid (1) was prepared and the in vitro relative expression of PPARγ, GLUT-4 and PPARα, was estimated. Compound 1 showed an increase of 2-fold in the mRNA expression of PPARγ isoform, 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 (NIDDM) rat model. The in vivo results indicated a significant decrease of plasma glucose levels, during the 7 h post-administration. Also, we performed a molecular docking of compound 1 into the ligand binding pocket of PPARγ, showing important short contacts with residues Ser289, His323 and His449 in the active site., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Compounds 1-10 were designed using a bioisosteric approach and were prepared using a short synthetic route. The in vitro inhibitory activity of the compounds against 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) was evaluated. Compounds 5 (α-series) and 10 (β-series) had a moderate inhibitory enzyme activity (55.26% and 67.03% inhibition at 10 μM, respectively) and were as active as BVT.14225 (positive control). Both compounds have a piperidine ring in their structure, but the most active (10) was selected to establish its in vivo antidiabetic effect using a non insulin-dependent diabetes mellitus rat model. The antidiabetic activity of compound 10 was determined at 50 mg/kg single dose in an acute model, and also by short term sub-chronic administration for 5 days. The results indicated a significant decrease of plasma glucose levels, similar than BVT.14225. Additionally, a molecular docking of the most active compounds of each series into the ligand binding pocket of one subunit of human 11β-HSD1 was performed. In this model the oxygen atom of the sulfonamide make hydrogen bond interactions with the catalytic residues Ser170 and Ala172. We also observed important π-π interactions between the naphthyl group and Tyr177., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)