Isolation,Purification and Characterisation of an Organic Solvent-Tolerant Ca2+-Dependent Protease from Bacillus megaterium AU02

A new organic solvent-tolerant strain Bacillus megaterium AU02 which secretes an organic solvent-tolerant protease was isolated from milk industry waste. Statistical methods were employed to achieve optimum protease production of 43.6 U/ml in shake flask cultures. The productivity of the protease was increased to 53 U/ml when cultivated under controlled conditions in a 7-L fermentor. The protease was purified to homogeneity by a three-step process with 24 % yield and specific activity of 5,375 U/mg. The molecular mass of the protease was found to be 59 kDa. The enzyme was active over a wide range of pH (6.0–9.0), with an optimum activity at pH 7.0 and temperature from 40 to 70 °C having an optimum activity at 50 °C. The thermal stability of the enzyme increased significantly in the presence of CaCl₂, and it retained 90 % activity at 50 °C for 3 h. The K _m and V _max values were determined as 0.722 mg/ml and 0.018 U/mg respectively. The metalloprotease exhibited significant stability in the presence of organic solvents with log P values more than 2.5, nonionic detergents and oxidising agent. An attempt was made to test the synthesis of aspartame precursor (Cbz-Asp-Phe-NH₂) which was catalysed by AU02 protease in the presence of 50 % DMSO. These properties of AU02 protease make it an ideal choice for enzymatic peptide synthesis in organic media.     

Isolation and Identification of α-Glucosidase and Protein Glycation Inhibitors from Stereospermum colais

Stereospermum colais (family Bignoniaceae) is a well-known pharmacologically potent medicinal plant reported in traditional systems of medicine. Phytochemical investigation of the roots of S. colais resulted in the isolation of seven compounds, and the metabolites were screened for its α-glucosidase enzyme inhibition and anti-glycation property. The compounds identified were β-sitosterol (1), 2-(4′-hydroxyphenyl) ethyl undecanoate (2), 2-(4′-hydroxyphenyl)ethyl pentadecanoate (3), 5α-ergosta-7,22-dien-3β-ol (4), ursolic acid (5), lapachol (6), and pinoresinol (7). Ursolic acid, lapachol, and pinoresinol possessed IC₅₀ values of 119.01, 130.29, and 125.62 nM, respectively, compared to standard ascorbic acid with an IC₅₀ value of 201.01 nM. The other compounds failed to show the activity. Results of the current study showcased the possible exploration of this medicinal plant for the treatment of type 2 diabetes in line with the development of phytopharmaceutical industry.     

Synthesis of novel zerumbone derivatives via regioselective palladium catalyzed decarboxylative coupling reaction: a new class of α-glucosidase inhibitors

A new strategy for the synthesis of novel zerumbone derivatives via a regioselective palladium catalyzed decarboxylative coupling reaction using arene carboxylic acids is described. The current methodology involves the repositioning of endocyclic double bond to exocyclic double bond of zerumbone. Preliminary in vitro analysis revealed that most of the newly synthesized derivatives are potent α-glucosidase enzyme inhibitors.     

TDCR measurements of 3H, 63Ni and 55Fe using Hidex 300SL LSC device

The commercial Hidex LSC system has been used to measure triple to double coincidence ratio (TDCR), experimental counting efficiency (CE) and the absolute activity for radioactive standards of pure beta emitters viz. ³H, ⁶³Ni and ⁵⁵Fe, an electron capture nuclide. Colour and chemical quench measurements of ⁶³Ni and ⁵⁵Fe have been done. An excellent match between TDCR and CE has been obtained for beta emitters, while very large deviations have been observed for ⁵⁵Fe. The deviation between TDCR and experimental efficiency has been found to be nearly uniform. Based on this, an empirical correction factor for TDCR which gives the correct efficiency has been evaluated, to enable efficient application of this commercial instrument for ⁵⁵Fe estimation. These TDCR correction factors were further validated by applying for ⁵⁵Fe activity measurements in ASTM standard steel samples irradiated to a fixed neutron flux in research reactor CIRUS. Finally, ⁵⁵Fe activity in steel sample from APSARA reactor decommissioning waste was successfully estimated using this modified TDCR.     

Efficient Ce(III)-Catalyzed cis-Selective Synthetic Approach to γ-Lactones in Aqueous Media

The first CeCl₃ · 7H₂O-catalyzed, one-pot synthesis of α-mercapto-γ-lactones via regioselective epoxide ring opening and mercaptoacetylative cyclization cascades in water is reported. The reaction between 2-methyl-2-phenyl-1,3-oxathiolan-5-one and a variety of terminal epoxides was carried out in aqueous media to afford γ-lactones in good to excellent yields (83–94%) with complete cis diastereoselectivity. Acetophenone obtained as a by-product was also recovered and recycled easily for further use.     

Template-directed approach to solid-phase combinatorial synthesis of furan-based libraries

A novel furan based scaffold 5-hydroxymethylfurfural has been identified for the generation of combinatorial libraries using template directed approach on solid phase. This scaffold has been utilized to afford furan-based bi-heterocyclic structures with extensive chemical diversity using cycloaddition, multicomponent and cyclization reactions.     

NiO/ZnO Composite Derived Metal-Organic Framework as Advanced Electrode Materials for Zinc Hybrid Redox Flow Battery

NiO/ZnO composite derived metal-organic framework (MOF) is used as to modify carbon felt (CF) via a conventional solid-state reaction followed by ultrasonication. The prepared electrode material is used in zinc-hybrid redox flow batteries (RFBs) due to their high redox activity of Zn²⁺/Zn. The electrochemical performance of composite modified CF and pre-treated CF was studied by cyclic voltammetry (CV) in 0.5 M aqueous zinc chloride with 5 M potassium hydroxide solutions showed clear confirmation for enhanced electrocatalytic activity. The unique porous structure of NiO/ZnO-derived MOF with increased surface area improves the battery behavior significantlyThe peak current ratio for the as-prepared material is about 3 times higher than that of the pre-treated CF due to more active sites. Zinc-based RFB with modified CF electrode exhibited better electrochemical performance with voltage efficiency (VE, 88 %), which is higher than true redox flow batteries.     

The Alzheimer's beta amyloid (Abeta1-39) monomer in an implicit solvent

Results from replica-exchange and regular room temperature molecular dynamics simulations of the Alzheimer's beta amyloid (Abeta(1-39)) monomer in an implicit solvent are reported. Our data indicate that at room temperature, the monomer assumes random-coil and soluble conformations. No beta content is observed which therefore seems to be a product of oligomerization and aggregation of monomers.     

β-Sitosterol Circumvents Obesity Induced Inflammation and Insulin Resistance by down-Regulating IKKβ/NF-κB and JNK Signaling Pathway in Adipocytes of Type 2 Diabetic Rats

β-sitosterol (SIT), the most abundant bioactive component of vegetable oil and other plants, is a highly potent antidiabetic drug. Our previous studies show that SIT controls hyperglycemia and insulin resistance by activating insulin receptor and glucose transporter 4 (GLUT-4) in the adipocytes of obesity induced type 2 diabetic rats. The current research was undertaken to investigate if SIT could also exert its antidiabetic effects by circumventing adipocyte induced inflammation, a key driving factor for insulin resistance in obese individuals. Effective dose of SIT (20 mg/kg b.wt) was administered orally for 30 days to high fat diet and sucrose induced type-2 diabetic rats. Metformin, the conventionally used antidiabetic drug was used as a positive control. Interestingly, SIT treatment restores the elevated serum levels of proinflammatory cytokines including leptin, resistin, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) to normalcy and increases anti-inflammatory adipocytokines including adiponectin in type 2 diabetic rats. Furthermore, SIT decreases sterol regulatory element binding protein-1c (SREBP-1c) and enhances Peroxisome Proliferator–activated receptor-γ (PPAR-γ) gene expression in adipocytes of diabetic rats. The gene and protein expression of c-Jun-N-terminal kinase-1 (JNK1), inhibitor of nuclear factor kappa-B kinase subunit beta (IKKβ) and nuclear factor kappa B (NF-κB) were also significantly attenuated in SIT treated groups. More importantly, SIT acts very effectively as metformin to circumvent inflammation and insulin resistance in diabetic rats. Our results clearly show that SIT inhibits obesity induced insulin resistance by ameliorating the inflammatory events in the adipose tissue through the downregulation of IKKβ/NF-κB and c-Jun-N-terminal kinase (JNK) signaling pathway.