Elucidation of the Inhibitory Effect of Phytochemicals with Kir6.2 Wild-Type and Mutant Models Associated in Type-1 Diabetes through Molecular Docking Approach

Pterostilbene protects cochlea from ototoxicity in streptozotocin-induced diabetic rats by inhibiting apoptosis

Diabetes mellitus (DM) causes ototoxicity by inducing oxidative stress, microangiopathy, and apoptosis in the cochlear sensory hair cells. The natural anti-oxidant pterostilbene (PTS) (trans-3,5-dimethoxy-4-hydroxystylbene) has been reported to relieve oxidative stress and apoptosis in DM, but its role in diabetic-induced ototoxicity is unclear. This study aimed to investigate the effects of dose-dependent PTS on the cochlear cells of streptozotocin (STZ)-induced diabetic rats. The study included 30 albino male Wistar rats that were randomized into five groups: non-diabetic control (Control), diabetic control (DM), and diabetic rats treated with intraperitoneal PTS at 10, 20, or 40 mg/kg/day during the four-week experimental period (DM + PTS10, DM + PTS20, and DM + PTS40). Distortion product otoacoustic emission (DPOAE) tests were performed at the beginning and end of the study. At the end of the experimental period, apoptosis in the rat cochlea was investigated using caspase-8, cytochrome-c, and terminal deoxyribonucleotidyl transferase-mediated dUTP-biotin end labeling (TUNEL). Quantitative real-time polymerase chain reaction was used to assess the mRNA expression levels of the following genes: CASP-3, BCL-associated X protein (BAX), and BCL-2. Body weight, blood glucose, serum insulin, and malondialdehyde (MDA) levels in the rat groups were evaluated. The mean DPOAE amplitude in the DM group was significantly lower than the means of the other groups (0.9–8 kHz; P < 0.001 for all). A dose-dependent increase of the mean DPOAE amplitudes was observed with PTS treatment (P < 0.05 for all). The Caspase-8 and Cytochrome-c protein expressions and the number of TUNEL-positive cells in the hair cells of the Corti organs of the DM rat group were significantly higher than those of the PTS treatment and control groups (DM > DM + PTS10 > DM + PTS20 > DM + PTS40 > Control; P < 0.05 for all). PTS treatment also reduced cell apoptosis in a dose-dependent manner by increasing the mRNA expression of the anti-apoptosis BCL2 gene and by decreasing the mRNA expressions of both the pro-apoptosis BAX gene and its effector CASP-3 and the ratio of BAX/BCL-2 in a dose-dependent manner (P < 0.05 compared to DM for all). PTS treatment significantly improved the metabolic parameters of the diabetic rats, such as body weight, blood glucose, serum insulin, and MDA levels, consistent with our other findings (P < 0.05 compared to DM for all). PTS decreased the cochlear damage caused by diabetes, as confirmed by DPOAE, biochemical, histopathological, immunohistochemical, and molecular findings. This study reports the first in vivo findings to suggest that PTS may be a protective therapeutic agent against diabetes-induced ototoxicity.

Drug Target Identification and Elucidation of Natural Inhibitors for Bordetella petrii: An In Silico Study

Environmental microbes like Bordetella petrii has been established as a causative agent for various infectious diseases in human. Again, development of drug resistance in B. petrii challenged to combat against the infection. Identification of potential drug target and proposing a novel lead compound against the pathogen has a great aid and value. In this study, bioinformatics tools and technology have been applied to suggest a potential drug target by screening the proteome information of B. petrii DSM 12804 (accession No. PRJNA28135) from genome database of National Centre for Biotechnology information. In this regards, the inhibitory effect of nine natural compounds like ajoene (Allium sativum), allicin (A. sativum), cinnamaldehyde (Cinnamomum cassia), curcumin (Curcuma longa), gallotannin (active component of green tea and red wine), isoorientin (Anthopterus wardii), isovitexin (A. wardii), neral (Melissa officinalis), and vitexin (A. wardii) have been acknowledged with anti-bacterial properties and hence tested against identified drug target of B. petrii by implicating computational approach. The in silico studies revealed the hypothesis that lpxD could be a potential drug target and with recommendation of a strong inhibitory effect of selected natural compounds against infection caused due to B. petrii, would be further validated through in vitro experiments.

Effect of pterostilbene on glioma cells and related mechanisms

Neuroglioma is the most common primary malignant tumor in neurosurgery. Due to unfavorable life quality of patients, the treatment of glioma is a major challenge in clinics. The search for effect treatment drugs thus benefits patient prognosis. As one derivative of resveratrol, pterostilbene has a wide spectrum of pharmaceutical functions, especially with the anti-tumor effects. This study thus investigated the effect of pterostilbene on neuroglioma and related mechanisms. U87 glioma cell line was divided into control, normal culture and different dosages of pterostilbene groups, which received 5 mM or 10 mM pterostilbene for 48 h. MTT assay was used to detect U87 cell proliferation, while invasion assay was employed to test the effect of pterostilbene on cell invasion, followed by flow cytometry assay for analyzing U87 cell apoptosis. Real-time PCR was used to test mRNA expression of Bcl-2 and Bax in glioma cells under the effect of pterostilbene, while Western blotting was used to detect alternation of Bcl-2 and Bax protein levels. Pterostilbene significantly inhibited proliferation and invasion abilities of glioma cells compared to those in control group (P<0.05). It can also enhance cell apoptosis, decrease mRNA and protein of Bcl-2 expression, and increase mRNA and protein expressions of Bax (P<0.05 compared to control group) in a dose-dependent manner. Pterostilbene can facilitate apoptosis of glioma cells, and inhibit their proliferation and invasion via mediating apoptotic/anti-apoptotic homeostasis.

Identification of Suitable Natural Inhibitor against Influenza A (H1N1) Neuraminidase Protein by Molecular Docking

The influenza A (H1N1) virus, also known as swine flu is a leading cause of morbidity and mortality since 2009. There is a need to explore novel anti-viral drugs for overcoming the epidemics. Traditionally, different plant extracts of garlic, ginger, kalmegh, ajwain, green tea, turmeric, menthe, tulsi, etc. have been used as hopeful source of prevention and treatment of human influenza. The H1N1 virus contains an important glycoprotein, known as neuraminidase (NA) that is mainly responsible for initiation of viral infection and is essential for the life cycle of H1N1. It is responsible for sialic acid cleavage from glycans of the infected cell. We employed amino acid sequence of H1N1 NA to predict the tertiary structure using Phyre2 server and validated using ProCheck, ProSA, ProQ, and ERRAT server. Further, the modelled structure was docked with thirteen natural compounds of plant origin using AutoDock4.2. Most of the natural compounds showed effective inhibitory activity against H1N1 NA in binding condition. This study also highlights interaction of these natural inhibitors with amino residues of NA protein. Furthermore, among 13 natural compounds, theaflavin, found in green tea, was observed to inhibit H1N1 NA proteins strongly supported by lowest docking energy. Hence, it may be of interest to consider theaflavin for further in vitro and in vivo evaluation.

Effects of pterostilbene on treating hyperprolactinemia and related mechanisms

Hyperprolactinemia (HPRL) frequently causes primary menopause and reproductive disorders. Pterostilbene is known to have anti-inflammation and modulation on cell apoptosis. However, its role in treating HPRL and potential mechanisms remain unclear yet. Healthy female virgin SD rats were randomly assigned into control, HPRL model group, bromocriptine treatment group, and low (20 mg/kg) and high (40 mg/kg) pterostilbene treatment groups. All groups except control ones received metoclopramide hydrochloride injection for generating HPRL model. Uterus and ovarian index in all animals were monitored. Prolactin (PRL), estradiol (E2), follicle stimulating hormone (FSH) and luteinizing hormone (LH) were quantified by ELISA. Caspase 3 activity was assayed, with real time PCR measuring Bcl-2 and Bax mRNA levels. HPRL rats had lower uterus and ovarian index, accompanied with elevated PRL, caspase 3 activity, Bax expression, and decreased FSH, LH, E2 and Bcl-2 expression as compared to control group (p<0.05). Pterostilbene treatment significantly increased uterus and ovarian index, FSH, LH, E2 and Bcl-2 expression, and decreased PRL, caspase 3 activity and Bax expression as compared to control group (p<0.05). 40 mg/kg pterostilbene had similar efficacy as those of bromocriptine. Pterostilbene exerts its function in the treatment of HPRL via modulating apoptosis-anti-apoptosis homeostasis, inhibiting serum PRL level, and regulating secretion of gonadotropin hormones.

Review of the Pharmacological Effects of Vitis vinifera (Grape) and its Bioactive Constituents: An Update

Vitis vinifera fruit (grape) contains various phenolic compounds, flavonoids and stilbenes. In recent years, active constituents found in the fruits, seeds, stems, skin and pomaces of grapes have been identified and some have been studied. In this review, we summarize the active constituents of different parts of V. vinifera and their pharmacological effects including skin protection, antioxidant, antibacterial, anticancer, antiinflammatory and antidiabetic activities, as well as hepatoprotective, cardioprotective and neuroprotective effects in experimental studies published after our 2009 review. Clinical and toxicity studies have also been examined. Copyright © 2016 John Wiley & Sons, Ltd.

Pterostilbene impact on retinal endothelial cells under high glucose environment

Diabetic retinopathy (DR) has complicated pathogenic factors. Studies showed that DR belongs to chronic inflammatory disease, and retinal endothelial cells oxidation by free radicals is one of its mechanisms. Pterostilbene, as the homologous derivative of resveratrol, has obvious antioxidant effect. Its influence on the DR has not been studied. This study intended to investigate the effect and mechanism of pterostilbene on human retinal endothelial cells (hRECs) under high glucose environment to illustrate pterostilbene impact on DR and provide basis for DR clinical treatment. hRECs cultured in high glucose environment were treated by 1.0 mmol/L pterostilbene. MTT assay was applied to test cell proliferation. ELISA was used to detect inflammatory factor TNF-α and IL-1β content. Real time PCR and Western blot were performed to examine NF-κB mRNA and protein expression. ROS and SOD activities were analyzed. Under high glucose environment, hRECs proliferation increased, TNF-α and IL-1β expression elevated, and NF-κB protein level upregulated significantly. On the other side, ROS production increased and SOD activity decreased obviously (P < 0.05). Pterostilbene can suppress hRECs over proliferation, decrease TNF-α and IL-1β, inhibit NF-κB protein expression, reduce ROS production, and increase SOD activity markedly compared with high glucose group (P < 0.05). Pterostilbene may delay DR progress through alleviating inflammation and antioxidation to suppress hRECs over proliferation.