Since activation of PPARγ is the main target for the antidiabetic effect of TZDs, especially when it heterodimerizes with RXR, we aimed to test the potential antidiabetic effect of phytol (250 mg/kg), the natural precursor of phytanic acid, a RXR ligand and/or pioglitazone (5 mg/kg) to diabetic insulin-resistant rats. Regarding the molecular docking simulation on PPARγ, phytanic acid, rather than phytol, showed a binding mode that mimics the crystal orientation of rosiglitazone and pioglitazone, forming H bonds with the same amino acids (S289, H 323, H 449 and Y 473), and the least energy level, which emphasizes their importance for PPARγ molecular recognition, activation, hence antidiabetic activity. In addition, docking on the RXRα/PPARγ heterodimer, revealed that phytanic acid has higher binding affinity and lesser energy score on RXRα, compared to the original ligand, retinoic acid. Phytanic acid binds by 3H bonds and shares retinoic acid in arginine (R 316). These results were further supported biochemically, where oral phytol and/or pioglitazone (5 mg/kg) improved significantly glucose homeostasis, lipid panel, raised serum adiponectin level and lowered TNF-α, reaching in most cases the effect of the 10 mg/kg pioglitazone. The study concluded that the insulin sensitizing/anti-diabetic effect of phytol is mediated by partly from activation of nuclear receptors and heterodimerization of RXR with PPARγ by phytanic acid.
BackgroundDiabetes is a major public health concern. In spite of continuous new drug development to treat diabetes, herbal remedies remain a potential adjunct therapy to maintain better glycemic control while also imparting few side-effects. Portulaca oleracea has been traditionally used to manage several diseases due to the anti-oxidant and anti-atherogenic effects it imparts. To better understand the mechanisms associated with potential protective effect of P. oleracea extract against diabetes, alloxan-induced diabetic rats were used in this study.MethodsForty Wistar rats (male, 7–8-wk-old, 140–160 g) were divided into four groups (n = 10/group): Group I (control), Group II (P. oleracea-treated; gavaged with P. oleracea extract daily [at 250 mg/kg] for 4 weeks), Group III (diabetic control; daily IP injection of alloxan [at 75 mg/kg] for 5 days) and Group IV (P. oleracea-pre-treated diabetic; gavaged with P. oleracea extract daily [at 250 mg/kg] for 4 weeks and then daily IP injection of alloxan [at 75 mg/kg] for 5 days). Body weight, food consumption, blood (serum) levels of glucose, C peptide, Hb A1C, insulin, tumor necrosis factor (TNF)-α and interleukin (IL)-6 were determined for all groups.ResultsThe results indicated that while Hb A1C, serum levels of glucose, TNF-α and IL-6 were all significantly decreased in the P. oleracea-pre-treated diabetic rats, these hosts also had significant increases in C peptide and insulin compared to levels in the counterpart diabetic rats. These results were confirmed by the histopathological assessments which showed marked improvement of the destructive effect on pancreatic islet cells induced by alloxan.ConclusionP. oleracea extract is a general tissue protective and regeneartive agent, as evidenced by increasing β-cell mass and therefore improved the glucose metabolism. Thus, stimulation of Portulaca oleracea signaling in β- cells may be a novel therapeutic strategy for diabetes prevention.
Aspirin and clopidogrel are the mainstay oral antiplatelet regimens, yet a substantial number of major adverse cardiac events (MACE) still occur. Herein, we investigated genetic and nongenetic factors associated with clopidogrel response in Egyptians. In all, 190 Egyptians with acute coronary syndrome (ACS) and/or percutaneous coronary intervention (PCI), treated with clopidogrel (75 mg/day) for at least a month, were genotyped for CYP2C19 *2, *3, *6, *8, *10, and *17, CES1 G143E and ABCB1*6 and *8. These variants along with nongenetic factors were tested for association with the risk of having MACE in clopidogrel‐treated patients. CYP2C19 loss‐of‐function (LOF) alleles carriers had increased risk of MACE vs. noncarriers (odds ratio 2.52; 95% confidence interval 1.23–5.15, P = 0.011). In a logistic regression, CYP2C19 LOF variants (P = 0.011), age (P = 0.032), and body mass index (BMI, P = 0.039) were significantly associated with the incidence of MACE in patients taking clopidogrel. CYP2C19 genetic variants, age, and BMI are potential predictors associated with variability to clopidogrel response in Egyptians.
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