Antidiabetic activity of Commiphora mukul and Phyllanthus emblica and Computational analysis for the identification of active principles with dipeptidyl peptidase IV inhibitory activity.

The medicinal plants may serve as natural alternatives to synthetic antidiabetic medications such as dipeptidyl peptidase-IV (DPP-IV) inhibitors, which are commonly prescribed in clinical practise. The medicinal plants: Commiphora mukul and Phyllanthus emblica have considerable DPP-IV inhibitory efficacy, according to our findings. The present study is an extension of the previous study conducted in our laboratory and was designed to confirm the antidiabetic effects of C. mukul and P. emblica in the streptozotocin diabetes model and elucidate the active principles responsible for DPP-IV inhibition. C. mukul (Guggul) and P. emblica (Amla) have the ability to inhibit DPP-IV and have anti-diabetic properties in a Type 2 diabetes mellitus experimental model. The binding sites and affinity of the active principles of C. mukul (Gluggusterone E, Gluggusterone Z) and P. emblica (Pzrogallol, beta-glucogallin, and gallic acid) responsible for DPP-IV enzyme inhibition were identified using in silico studies and compared to Vildagliptin, a synthetic DPP-IV inhibitor. The Vildagliptin and therapy groups had significantly lower glycated hemoglobin and DPP-IV levels. The anti-diabetic effect of C. mukul and P. emblica is due to their DPP-IV inhibitory action. The DPP-IV inhibitory action of Gluggusterone E, Gluggusterone Z, and beta-Glucogallin was found to be superior to Vildagliptin in docking tests.

A novel stop-loss DAX1 variant affecting its protein-interaction with SF1 precedes the adrenal hypoplasia congenital with rare spontaneous precocious puberty and elevated hypothalamic-pituitary-gonadal/adrenal axis responses.

The case study unveils the likely mechanism of a novel stop-loss DAX1 variant preceding the prolonged precocious puberty in the adrenal hypoplasia congenital (AHC) boy. A boy aged five years and nine months initially examined for the primary adrenal insufficiency symptoms. Next-generation sequencing confirmed the X-linked inheritance of a novel stop-loss DAX1 variant: c.1411T>C/p.Ter471Gln associated with AHC in the patient. The patient was subjected to a brief clinical follow-up from 11 to 15.1 years of age. The effect of the mutant-DAX1 variant (p.Ter471Gln) on DAX1-steroidogenic factor 1 (SF1) (protein-protein) interaction was studied by protein-protein docking using the ClusPro-online tool. At 5.9 yrs of age, the patient exhibited precocious puberty with the secondary sexual characteristics of Tanner 2 stage (of 9-14 yrs of age). The patient showed primary adrenal insufficiency with diminished cortisol concentrations at blood serum (25 ng/ml) and urine (3.55 µg/24 h) levels. Upon steroidal exposure, the patient showed normalized serum cortisol levels of 45-61 ng/ml. However, the precocious puberty got prolonged with the increased penis length of 8.5 cm and the bone age of 18 yrs old during the follow-up. The patient showed increased basal serum adrenocorticotropic hormone (110->2000 pg/ml) and follicle-stimulating hormone (18.4-22.3 mIU/ml) concentrations. Following an elevated hypothalamic-pituitary-gonadal axis activity witnessed upon gonarellin stimulation. Protein-protein docking confirmed a weaker interaction between the mutant-DAX1 (p.Ter471Gln) protein and the wild-SF1 protein. Overall, we hypothesize the weakened mutant-DAX1-SF1 (protein-protein) interaction could govern the prolonged precocious puberty augmented with the elevated hypothalamic-pituitary-gonadal/adrenal axis responses via SF1-induced neuronal nitric oxide synthetase activation in the patient.

Role of Phosphorylation and Hyperphosphorylation of Tau in Its Interaction with ßα Dimeric Tubulin Studied from a Bioinformatics Perspective.

BACKGROUND: Tau is a disordered Microtubule Associated Protein (MAP) which prefers to bind and stabilize microtubules. Phosphorylation of tau in particular enhances tautubulin interaction which otherwise detaches from tubulin during hyperphosphorylation. The reason behind their destabilization, detachment and the role of ß subunit (from microtubule) and the projection domain (Tau) in microtubule stability remains elusive till date. Thus, a complete 3D structural investigation of tau protein is much needed to address these queries as the existing crystal structures are in fragments and quite limited. METHODS: In this study, the modelled human tau protein was subjected to phosphorylation and hyperphosphorylation which were later considered for docking with micro-tubules (ßα subunits-inter dimer) and vinblastine. RESULTS: Phosphorylated tau protein interacts with both α- and ß subunits. But stronger bonding was with α- compared to ß subunits. Regarding ß subunit, proline rich loop and projection domain actively participated in tau binding. Interestingly, hyperphosphorylation of tau increases MAP domain flexibility which ultimately results in tau detachment, the main reason behind tangle formation in Alzheimer's disease. CONCLUSION: This study being the first of its kind emphasizes the role of projection domain and proline rich region of ß-subunit in stabilizing the tau-tubulin interaction and also the effect of hyperphosphorylation in protein-protein and protein-drug binding.

Dipeptidyl peptidase IV Inhibitory activity of Terminalia arjuna attributes to its cardioprotective effects in experimental diabetes: In silico, in vitro and in vivo analyses.

BACKGROUND: The marketed synthetic (Dipeptidyl peptidase-IV) DPP-IV Inhibitors are expensive antidiabetic drugs and have been reported to cause unacceptable adverse effects such as pancreatitis, angioedema, thyroid and pancreatic cancers. In this scenario research to develop novel DPP-IV Inhibitors from alternative sources is the need of the hour. HYPOTHESIS/PURPOSE: Terminalia arjuna, a medicinal herb with antidiabetic and cardioprotective activities may represent a natural DPP-IV Inhibitor, the DPP-IV Inhibitory activity of which may translate into demonstrable therapeutic benefits in setting of diabetes with cardiovascular co-morbidities. STUDY DESIGN: The study type used for the present study was an experimental (In vitro, In vivo and In silico) design. METHOD: The DPP-IV Inhibitory, antidiabetic and cardioprotective effects of Terminalia arjuna was evaluated in the experimental model of myocardial infarction co-existing with diabetes. To determine the active principle of Terminalia arjuna responsible for DPP-IV Inhibitory activity, the crystal structure of DPP-IV was considered as receptor which was docked against Arjunetin, Arjungenin, Arjunic acid, Arjunone, Ellagic acid, Gallic acid, Sitagliptin and Vildagliptin. The binding sites as well as affinity of various active ingredients of Terminalia arjuna for DPP- IV enzyme was elucidated using in silico studies and compared to Vildagliptin. RESULTS: Terminalia arjuna demonstrated significant DPP-IV Inhibitory, antidiabetic (significant reduction in HbA1C) and cardioprotective effects (restoration of myocardial CPK-MB) in the experimental model of myocardial infarction co-existing with diabetes. The cardioprotective efficacy correlated to its DPP-IV Inhibitory activity. The active ingredients of Terminalia arjuna (Arjunetin, Arjungenin, Arjunic Acid Arjunone, Ellagic acid and Gallic acid) demonstrated significant inhibition of DPP-IV enzyme. Arjunic acid and Arjunone prefers the active site pocket of DPP-IV enzyme. Compounds like Arjunetin and Vildagliptin prefers to bind near the interface region of the DPP-IV as their biological active forms are homodimer. Sitagliptin binds near the α/ß hydrolase domain. CONCLUSION: The DPP-IV Inhibitory activity of Terminalia arjuna was found to be comparable to Vildagliptin. The DPP-IV Inhibitory activity translated into significant cardioprotective effects in the setting of diabetes. The active ingredient of Terminalia arjuna; Arjunetin, Arjungenin, Ellagic acid and Arjunic acid showed superior DPP-IV Inhibitory activity as compared to synthetic DPP-IV inhibitors (Sitagliptin and Vildagliptin) based on results of docking studies.