1.Exploration of Novel Human Tyrosinase Inhibitors by Molecular Modeling, Docking and Simulation Studies.
Hassan M1, Ashraf Z1,2, Abbas Q1, Raza H1, Seo SY3. Interdiscip Sci. 2016 Apr 21. [Epub ahead of print]
Research studies on human tyrosinase inhibitors and exploration for better cytotoxic agents remain an important line in drug discovery and development at the present time. Recently, multiple inhibitors are being used to cure melanogenesis by targeting human tyrosinase. A series of coumarin (C1-C9)-, thymol (T1-T8)- and vanillin (V1-V8)-based derivatives have been theoretically analyzed for their inhibitory effects against human tyrosinase. The crystal structure of human tyrosinase is not available in Protein Data Bank. Therefore, homology modeling approach was used to predict three-dimensional (3D) crystal structure of human tyrosinase. The reliability and efficacy of predicted 3D structure were validated by using Ramachandran plots which indicate that 95.01 % residues are present in favored regions. Moreover, multiple computational approaches such as molecular docking and molecular dynamic (MD) simulation along with various online tools were employed to screen the best inhibitor against melanogenesis.
2.Enzyme mediated synthesis of polypyrrole in the presence of chondroitin sulfate and redox mediators of natural origin.
Grijalva-Bustamante GA1, Evans-Villegas AG2, Del Castillo-Castro T3, Castillo-Ortega MM1, Cruz-Silva R4, Huerta F5, Morallón E6. Mater Sci Eng C Mater Biol Appl. 2016 Jun 1;63:650-6. doi: 10.1016/j.msec.2016.03.042. Epub 2016 Mar 16.
Polypyrrole (PPy) was synthesized by enzyme mediated oxidation of pyrrole using naturally occurring compounds as redox mediators. The catalytic mechanism is an enzymatic cascade reaction in which hydrogen peroxide is the oxidizer and soybean peroxidase, in the presence of acetosyringone, syringaldehyde or vanillin, acts as a natural catalysts. The effect of the initial reaction composition on the polymerization yield and electrical conductivity of PPy was analyzed. Morphology of the PPy particles was studied by scanning electron microscopy and transmission electron microscopy whereas the chemical structure was studied by X-ray photoelectron and Fourier transformed infrared spectroscopic techniques. The redox mediators increased the polymerization yield without a significant modification of the electronic structure of PPy. The highest conductivity of PPy was reached when chondroitin sulfate was used simultaneously as dopant and template during pyrrole polymerization.
3.Vanillin mitigates potassium bromate-induced molecular, biochemical and histopathological changes in the kidney of adult mice.
Ben Saad H1, Driss D2, Ellouz Chaabouni S2, Boudawara T3, Zeghal KM4, Hakim A4, Ben Amara I5. Chem Biol Interact. 2016 Apr 10;252:102-113. doi: 10.1016/j.cbi.2016.04.015. [Epub ahead of print]
The present study aimed to explore the ability of vanillin to ameliorate the adverse effects induced by potassium bromate (KBrO3) in the renal tissue. Our results showed a significant increase in hydrogen peroxide, superoxide anion, malondialdehyde, advanced oxidation protein product and protein carbonyl levels in the kidney of KBrO3 treated mice, compared with the control group. Nephrotoxicity was evidenced by a decrease in plasma uric acid and kidney glutathione levels, Na+-K+-ATPase, lactate dehydrogenase and catalase activities. Additionally, creatinine and urea levels significantly increased in the plasma and declined in the urine. Also, Kidney glutathione peroxidase, superoxide dismutase, metallothionein (MT1 and MT2) mRNA expression remarkably increased. These modifications in biochemical and molecular values were substantiated by histopathological data. Co-treatment with vanillin restored these parameters to near control values. Interestingly, vanillin proved to possess, in vitro, a stronger scavenging radical activity than vitamin C and Trolox.
4.Effects of Inhibiting Acylated Homoserine Lactones (AHLs) on Anammox Activity and Stability of Granules'.
Zhao R1, Zhang H2, Zou X1, Yang F1. Curr Microbiol. 2016 Apr 9. [Epub ahead of print]
In this study, the effects of AHL-based QS signals on anammox activity and stability of granules' were investigated. Results clearly showed that the vanillin and porcine kidney acylase I could reduce the AHLs in anammox bacteria. Inactivation of AHLs by vanillin and porcine kidney acylase I depressed the nitrogen removal ability of anammox bacteria. A significant inhibition of specific anammox activity was observed when the concentration of vanillin and porcine kidney acylase I increased to 1 g/L. Anammox activity was depressed on enzyme level. Moreover, degradation of AHLs under vanillin and AHL-acylase exposure could result in anammox granules' disintegration. Further research showed that the contents of protein (PN) and polysaccharides (PS) in extracellular polymeric substances were reduced with AHLs blocked, and it further explained the instability and weakening strength of the anammox granules. The results of our investigation provided new insight into the AHL-based QS-regulated anammox activity, leading a potential way to enhance stability of anammox granules.