[Show abstract][Hide abstract] ABSTRACT: In this study, enhanced synergistic bioactivity of zinc oxide nanoparticles (ZnO NPs) with β-lactam antibiotics were evaluated against a panel of clinically isolated extended spectrum β-lactamase producers implicated in urinary tract infections. Chemically synthesized zinc oxide nanoparticles (15 nm) were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmittance electron microscopy (HR-TEM), selective area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS), and UV–Visible spectrophotometry techniques. The antimicrobial potency (10 ± 0.66, 12, 11.33 ± 1.10, and 0.7 ± 0.66 mm inhibiting zone) and minimum inhibitory concentrations (80, 60, 30, 50 μg/ml) of ZnO NPs were tested separately whereas time–kill and membrane leakage assays were evaluated in combination with ZnO NPs+ cefotaxime, ampicillin, ceftriaxone, cefepime against the β-lactamase producer strains of E. coli, K. pneumoniae, S. paucimobilis, and P. aeruginosa, respectively. Time–kill curve dynamics of ZnO NPs with β-lactam antibiotics revealed enhanced bactericidal activity (50, 85, 58, 50 % fold inhibition) by delaying the exponential and stationary phases of all isolates when tested separately. Posttime–kill effect was studied on cell membrane by assaying leakage of reducing sugars (130.2, 124.7, 137, and 115.8 μg/bacterial dry weight of 1 mg (μg/mg) and proteins (15, 10, 16, 18 μg/mg). These assays revealed that membrane leakage was due to synergism of ZnO NPs+ β-lactam antibiotics which successfully damage cell membrane thereby leading to death of all ESBL producers. The results demonstrate the utilization of ZnO NPs as a potentiator of β-lactam antibiotics and suggest the possibility to use nanoparticles in a combination therapy to treat UTI.
Journal of Nanoparticle Research 01/2013; 15(1). DOI:10.1007/s11051-012-1413-4 · 2.18 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Xanthine oxidase (XO) generates superoxide anions and H(2)O(2) for the self-defence system of organism. Abnormal production of this superoxide's (reactive oxygen species) is responsible for a number of complications including inflammation, metabolic disorder, cellular aging, reperfusion damage, atherosclerosis and carcinogenesis. Series of novel trisubstituted thiophenyl-1-thiazolyl-2-pyrazoline libraries are synthesized containing 2,5-dichloro thiophene, 5-chloro-2-(benzylthio) thiophene and 5-chlorothiophene-2-sulphonamide, from chalcones in PEG-400 as green solvent. Superoxide (XO) inhibitory and free radical scavenging activities were also figured out with molecular modeling analysis, bearing in mind their possible future for super oxide inhibitor (Gout) therapeutics, compound 3k shows interesting superoxide inhibitory and free radical scavenger activity with IC(50)=6.2μM, in comparison with allopurinol.
[Show abstract][Hide abstract] ABSTRACT: Drug development in the recent times often relies on use of natural and synthetic drugs that are promising candidates as therapeutic agents for prevention of diseases and disorders. They possess different chemical structures with wide range of therapeutic activities. Many natural and synthetic drugs act as antioxidant agents in various metabolic processes. Increasing epidemiological, clinical and experimental studies have shown that intake of antioxidants drugs provide protection against various disorders and diseases related to oxidative stress. The factors responsible for this oxidative stress are mainly free radicals, reactive nitrogen species (RNS) and reactive oxygen species (ROS). The antioxidant drugs act as free radical scavenging, reducing and metal chelating substances; Antioxidants also show inhibition of various metabolic enzymes and factors responsible for inflammation. The present paper reviews different In vitro assays for determination of antioxidant activities (Table 1). The basic assays include DDPH assay, OH Scavenging assay, Reducing activity assay, TEAC assay, FCR assay, PRTC assay, ABTS assay, FRAP assay, ORAC assay, Ferric thiocynate assay, TRAP assay, Chemiluminescence assay, NBT assay, CUPRAC Assay.
Mini Reviews in Medicinal Chemistry 05/2012; 12(10):1007-14. DOI:10.2174/138955712802762310 · 2.90 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Uricase (EC 126.96.36.199, UC) catalyzes the oxidation of uric acid (UA) to more soluble allantoin thereby lowering plasma UA levels. In humans, when concentration of UA exceeds >7mg/dl, it leads to hyperuricemia, gout, nephrolithiasis and urolithiasis. A new remedy to cure such metabolic diseases is the enzyme supplementation therapy by UC but with high degree of antigenic independence. Therefore screening of new uricase sources to expand its usefulness and reduced antigenecity is needed. Present study employed cheminformatics approach to construct models of reported UC from different sources viz. Bacillus megaterium, Streptomyces bingchenggensis BCW-1, Paenibacillus sp, Solibacter usitatus Ellin6076, Truepera radiovictrix DSM 17093 and Ktedonobacter racemifer DSM 4496 in order to study their structure-function relationship for enzyme mass production and modification for improved characteristics. BioMed CAChe version 6.1 was further used to study enzyme-substrate interactions of models with uric acid using docking approach. Results indicated that models for UC of Streptomyces bingchenggensis BCW-1 accounted for better regio-specificity towards UA, supporting the interested metabolism and thus may further be implicated in enzyme supplementation therapy for hyperuricemic associated disorders.
Computers in Biology and Medicine 04/2012; 42(6):657-66. DOI:10.1016/j.compbiomed.2012.03.001 · 1.24 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Kidney stones are the crystal formation or deposition of calcium oxalate inside the kidney due to excess intake of calcium rich food. The current therapies are either expensive, painful, long term process with side effects and most cases reoccurrence of kidney stones during the therapy was observed.. The present invention is cost effective, short term, non toxic, non invasive, and decrease in efficacy. The polyherbal formulation contains the eight (at least five) different medicinal plants such as Tribulus terrestris L. Hygrophila spinosa L. Ricinnus communis L. Celosia argentea L. Coleus blumei Benth, Paederia foetida L- Bryophyllum pinnatum (Lam) and Amaranthus spinosus L. which are available easily in local forest from Nanded Maharashtra. The polyherbal formulation mixture (1 teaspoonful) administrated with honey or curd for 28 days to effectively treat the kidney stones. Complete elimination of calculi or a decrease in the stone growth was observed in most of the urolithiatic patients. The polyherbal formulation is an alternative treatment method in the management of urolithiasis.
[Show abstract][Hide abstract] ABSTRACT: In humans oxalate is end product of protein metabolism, with no enzyme present to act on it. In conditions of its enhanced endogenous synthesis or increased absorption from the diet, oxalate accumulation leads to hyperoxaluria which can further lead to a number of pathological conditions including urolithiasis. Urolithiasis has been a perplexing problem due to its high incidence and rate of recurrence after treatment like Extracorporeal-shock wave lithotripsy (ESWL). Hence other prophylactic treatment becomes necessary. One of the newer approaches of curing such metabolic disorders is the enzyme supplementation therapy. Oxalate oxidase (OxOx) is a commonly occurring enzyme in plants, bacteria and fungi that catalyses oxidative cleavage of oxalate to CO(2) with reduction of dioxygen to H(2)O(2). Present study, used Hordeum vulgare OxOx crystal structure (PDB ID 2ET1A) as a template for constructing 3D models of OxOx from Triticum aestivum, Arabidopsis thaliana, Sclerotiana sclerotiarum. Similarly Homology models for isoforms Ceriporiopsis subvermispora 336, C. subvermispora 422 were constructed by using template Bacillus subtilis oxalate decarboxylase (Oxdc) (PDB ID 2UY8A) by comparative modeling approach in SWISS MODEL, MODELLER, 3D JIGSAW and GENO 3D program server. Based on overall stereochemical quality (PROCHECK, PROSA, VARIFY 3D), best models were selected, energy minimized, refined and characterized for active site in BioMed CaChe V 6.1 workspace. Selected models were further studied for structure function relationship with substrate (oxalate) and its analogue (glycolate) by using docking approach. Calculated interaction energy between the oxalate and constructed enzyme indicated that homology models for OxOx of T. aestivum, A. thaliana and S. sclerotiarum, can account for better regio-specificity of this enzyme towards oxalate. That supports the interested metabolism and thus may further implement in enzyme supplementation therapy for urolithiasis.
International journal of biological macromolecules 04/2011; 48(3):466-73. DOI:10.1016/j.ijbiomac.2011.01.007 · 2.86 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Glycolate oxidase (GOX) is one of the principal enzymes involved in the pathway of oxalate synthesis. It converts glycolate to glyoxylate by oxidation and then glyoxylate is finally converted to oxalate. Therapeutic intervention of GOX in this consequence thus found potential in the treatment of calcium oxalate urolithiasis. In present investigation, we explored GOX in search of potential leads from traditional resources. Molecular modeling of the identified leads, quercetin and kaempherol, was performed by employing Glide 5.5.211 (SchrodingerTM suite). In the absence of pure human glycolate oxidase (hGOX) preparation, in vitro experiments were performed on spinach glycolate oxidase (sGOX) as both enzymes possess 57% identity and 76% similarity along with several conserved active site residues in common. We aimed to identify a possible mechanism of action for the anti-GOX leads from Tribuls terrestris, which can be attributed to anti-urolithic drug development. This study found promising in development of future GOX inhibitory leads.
International journal of biological macromolecules 03/2011; 49(1):62-70. DOI:10.1016/j.ijbiomac.2011.03.016 · 2.86 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In the present article, we have synthesized a combinatorial library of 3,5-diaryl pyrazole derivatives using 8-(2-(hydroxymethyl)-1-methylpyrrolidin-3-yl)-5,7-dimethoxy-2-phenyl-4H-chromen-4-one (1) and hydrazine hydrate in absolute ethyl alcohol under the refluxed conditions. The structures of the compounds were established by IR, (1)H NMR and mass spectral analysis. All the synthesized compounds were evaluated for their anticancer activity against five cell lines (breast cancer cell line, prostate cancer cell line, promyelocytic leukemia cell line, lung cancer cell line, colon cancer cell line) and anti-inflammatory activity against TNF-alpha and IL-6. Out of 15 compounds screened, 2a and 2d exhibited promising anticancer activity (61-73% at 10 microM concentration) against all selected cell lines and IL-6 inhibition (47% and 42% at 10 microM concentration) as in comparison to standard flavopiridol (72-87% inhibition at 0.5 microM) and dexamethasone (85% inhibition at 1 microM concentration), respectively. Cytotoxicity of the compounds checked using CCK-8 cell lines and found to be nontoxic to slightly toxic. Out of 15, four 3,5-diaryl pyrazole derivatives exhibiting potent inhibitory activities against both the monophenolase and diphenolase actions of tyrosinase. The IC(50) values of compounds (2a, 2d, 2h and 2l) for monophenolase inhibition were determined to range between 1.5 and 30 microM. Compounds 2a, 2d, 2h and 2l also inhibited diphenolase significantly with IC(50) values of 29.4, 21.5, 2.84 and 19.6 microM, respectively. All four 3,5-diaryl pyrazole derivatives were active as tyrosinase inhibitors (2a, 2d, 2h and 2l), and belonging to competitive inhibitors. Interestingly, they all manifested simple reversible slow-binding inhibition against diphenolase.
[Show abstract][Hide abstract] ABSTRACT: Hyperuricemia is a condition of defective purine metabolism characterized with elevated serum uric acid (UA) level that further leads to gout and gouty nephrolithiasis disorders. Gout is a world wide distributed rheumatic disease comprises 1% of the total population and still is in increasing state. One of the factors contributing to overproduction of UA is the hydroxylation of xanthine catalyzed by xanthine oxidase (XO). In the present study, 3D modeling of Arthrobacter sp. XL26 (xodB) protein was performed by comparative modeling approach using Rhodobacter capsulatus XDH (PDB ID: 2W3sF) as template in SWISS-MODEL, Geno3D and MODELLER program server. The best model was selected based on overall stereochemical quality (Procheck, PROSA, GenThreader), energy minimized, refined and used for active site characterization in BioMed CAChe workspace. The enzyme-inhibitor interaction was studied by docking to screen the possible inhibitors and application of model in design and development of anti-gout agents.
International journal of biological macromolecules 08/2010; 47(2):298-303. DOI:10.1016/j.ijbiomac.2010.04.002 · 2.86 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidin-4-one derivatives have been prepared by cyclocondensation of ethyl 2-cyano-3,3-bis(methylthio)prop-2-enoate with 2-amino-4-(substitutedphenyl)thiazole to give 3-cyano-2-methylthio-4-oxo-4H-6-(substitutedphenyl)thiazolo[3,2-a]pyrimidin (2a-j) and further reacting with hydrazine hydrate to yield the target compounds (3a-j). The chemical structure of the compounds was confirmed by IR and (1)H NMR spectral data. All the compounds of the series have been screened for their antibacterial and antifungal activity studies. The result revealed that all compounds showed significant antimicrobial activity.
European Journal of Medicinal Chemistry 04/2010; 45(4):1635-8. DOI:10.1016/j.ejmech.2009.12.040 · 3.45 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Chalcones have been identified as interesting compounds with cytotoxicity, anti-inflammatory and antioxidant properties. In the present study, simple methoxychalcones were synthesized by Claisen-Schmidt condensation reaction and evaluated for above biological activities. The structures of the compounds were established by IR, (1)H NMR and mass spectral analysis. The data revealed that compound 3s (99-100% at 10 microM concentration) completely inhibit the selected five human cancer cell lines as compared to standard flavopiridol and gemcitabine (70-90% at 700 nM and 500 nM concentrations, respectively), followed by 3a, 3n,3o,3p,3q,3r. Among the tested compounds 3l, 3m, 3r, and 3s exhibited promising anti-inflammatory activity against TNF-alpha and IL-6 with 90-100% inhibition at 10 microM concentration. DPPH free radical scavenging activity was given by the compounds 3o, 3n, 3l, 3r, 3m, 3a, 3p, 3c and 3s at 1mM concentration. Overall, 3s was obtained as lead compound with promising anticancer, anti-inflammatory and antioxidant activities. Bioavailability of compounds were checked by in vitro cytotoxicity study and confirmed to be nontoxic. The structure activity relationship (SAR) and in silico drug relevant properties (HBDs, HBAs, PSA, cLogP, ionization potential, molecular weight, E(HOMO) and E(LUMO)) further confirmed that the compounds were potential candidates for future drug discovery study.
[Show abstract][Hide abstract] ABSTRACT: Plumbago zeylanica (Chitrak) is a useful Indian medicinal plant. The root of
the plant and its constituents are credited with potential therapeutic properties. The
isolation and spectral data for new flavonoid 2-(2, 4-Dihydroxy-phenyl)-3, 6, 8-
trihydroxy-chromen-4-one from the roots of Plumbago zeylanica were determined
and the antioxidant activity were studied by free radical scavenging and superoxide
radical scavenging assays. The plant roots extract reveled significant antioxidant
activity as compared to standard flavonoid (quercetin). The antioxidant activity by
DPPH is 96μg/ml and by NBT is 4.6μg/ml which grater than that of standard
(Quercetin) 45 μg/ml by DPPH and 10μg/ml by NBT assay. The phytochemical
investigation showed presence of flavonoids, tannins and saponins. The total phenolic
and total flavonoid content was found to be 260±48.0 and 45.5±5.2 mg of GAE/g and
[Show abstract][Hide abstract] ABSTRACT: L-asparaginase was extracted from Erwinia carotovora and purified by ammonium sulfate fractionation (60-70%), Sephadex G-100, CM cellulose, and DEAE sephadex chromatography. The apparent Mr of enzyme under nondenaturing and denaturing conditions was 150 kDa and 37 ± 0.5 kDa, respectively. L-asparaginase activity was studied in presence of thiols, namely, L-cystine (Cys), L-methionine (Met), N-acetyl cysteine (NAC), and reduced glutathione (GSH). Kinetic parameters in presence of thiols (10-400 μM) showed an increase in V(max) values (2000, 2223, 2380, 2500, and control 1666.7 μmoles mg(-1)min(-1)) and a decrease in K(m) values (0.086, 0.076, 0.062, 0.055 and control 0.098 mM) indicating nonessential mode of activation. K(A) values displayed propensity to bind thiols. A decrease in V(max)/K(m) ratio in concentration plots showed inverse relationship between free thiol groups (NAC and GSH) and bound thiol group (Cys and Met). Enzyme activity was enhanced in presence of thiol protecting reagents like dithiothreitol (DTT), 2-mercaptoethanol (2-ME), and GSH, but inhibited by p-chloromercurybenzoate (PCMB) and iodoacetamide (IA).
[Show abstract][Hide abstract] ABSTRACT: Xanthine oxidase (XO) is responsible for the pathological condition called gout. Inhibition of XO activity by various pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidine-4-one derivatives was assessed and compared with the standard inhibitor allopurinol. Out of 10 synthesized compounds, two compounds, viz. 3-amino-6-(2-hydroxyphenyl)-1H-pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidin-4-one (3b) and 3-amino-6-(4-chloro-2-hydroxy-5-methylphenyl)-1H-pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidin-4-one (3g) were found to have promising XO inhibitory activity of the same order as allopurinol. Both compounds and allopurinol inhibited competitively with comparable Ki (3b: 3.56 microg, 3g: 2.337 microg, allopurinol: 1.816 microg) and IC(50) (3b: 4.228 microg, 3g: 3.1 microg, allopurinol: 2.9 microg) values. The enzyme-ligand interaction was studied by molecular docking using Autodock in BioMed Cache V. 6.1 software. The results revealed a significant dock score for 3b (-84.976 kcal/mol) and 3g (-90.921 kcal/mol) compared with allopurinol (-55.01 kcal/mol). The physiochemical properties and toxicity of the compounds were determined in silico using online computational tools. Overall, in vitro and in silico study revealed 3-amino-6-(4-chloro-2-hydroxy-5-methylphenyl)-1H-pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidin-4-one (3g) as a potential lead compound for the design and development of XO inhibitors.
Journal of Enzyme Inhibition and Medicinal Chemistry 12/2009; 25(5):615-21. DOI:10.3109/14756360903389849 · 2.33 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Purified L-asparaginase in combination with other anticancer drugs like pyrimidinederivatives is administered usually in the body to treat ALL. In the present study, L-asparaginase waspurified from Erwinia carotovora up to 247.6 fold and its catalytic properties were studied in thepresence of eight different dihydropyrimidine (DHP) derivatives, out of eight derivatives only two viz4- (2'-hydroxy phenyl) -6- methyl -2- thioxo)-1 -N - benzilydene - 1, 4 - dihydropyrimidine - 5 -carboxylic acid ethyl ester (P1) and 4 -(2'-hydroxy-5'-chlorophenyl)-5-acetyl-6-methyl-2 pyrimidinone(P2) were found to be activators of L-asparaginase. Their catalytic effect was assayed at optimum pH8.6 and at temperature 35°C in the absence and presence of derivatives P1 and P2 (20-40 μM) at 0.02-0.1 mM concentration of asparagine. It was found that derivatives below the concentration 5 μg/mlhave no effect on the activity. Derivative P1 is found to be a strong activator of the asparaginaseactivity that was reflected by an increase in the Vmax (1.75 fold by P1 and 2.80 fold by P2 respectively)and decrease in the Km (0.91 fold by P1 and 0.81 fold by P2 respectively). The activation ofasparaginase is explained by suppressing the cooperativity for the substrate, producing hyperbolickinetics with Km of 0.080 mM and by 3 fold increase in the Vmax of the enzyme. The activation byderivative P1 and P2 were additive, at optimal or suboptimal concentrations of both activators (up to 30μg/ ml). The DHP derivatives were further analyzed for quantitative SAR study (QSAR) by usingPASS, online software to determine their Pa value. Toxicity and drug relevant properties wereanalyzed by PALLAS software in terms of their molecular weight and log p values. The resultsshowed both the derivatives P1 and P2 are positive modulators of asparaginase activity and maysupport the development of novel combination therapy for the treatment of Leukemia and solid bloodtumors.
[Show abstract][Hide abstract] ABSTRACT: An extra cellular lipase was isolated and purified from the culture broth of Pseudomonas aeruginosa SRT 9 to apparent homogeneity using ammonium sulfate precipitation followed by chromatographic techniques on phenyl Sepharose CL-4B and Mono Q HR 5/5 column, resulting in a purification factor of 98 fold with specific activity of 12307.8 U/mg. The molecular weight of the purified lipase was estimated by SDS-PAGE to be 29 kDa with isoelectric point of 4.5. Maximum lipase activity was observed in a wide range of temperature and pH values with optimum temperature of 55°C and pH 6.9. The lipase preferably acted on triacylglycerols of long chain (C14-C16) fatty acids. The lipase was inhibited strongly by EDTA suggesting the enzyme might be metalloprotein. SDS and metal ions such as Hg2+, Zn2+, Cu2+, Ag2+ and Fe2+ decreased the lipase activity remarkedly. Its marked stability and activity in organic solvents suggest that this lipase is highly suitable as a biotechnological tool with a variety of applications including organo synthetic reactions and preparation of enantiomerically pure pharmaceuticals. The Km and Vmax value of the purified enzyme for triolein hydrolysis were calculated to be 1.11 mmol/L and 0.05 mmol/L/minrespectively.
[Show abstract][Hide abstract] ABSTRACT: An extra cellular lipase was isolated and purified from the culture broth of Pseudomonas aeruginosa SRT 9 to apparent homogeneity using ammonium sulfate precipitation followed by chromatographic techniques on phenyl Sepharose CL- 4B and Mono Q HR 5/5 column, resulting in a purification factor of 98 fold with specific activity of 12307.8 U/mg. The molecular weight of the purified lipase was estimated by SDS-PAGE to be 29 kDa with isoelectric point of 4.5. Maximum lipase activity was observed in a wide range of temperature and pH values with optimum temperature of 55ºC and pH 6.9. The lipase preferably acted on triacylglycerols of long chain (C14-C16) fatty acids. The lipase was inhibited strongly by EDTA suggesting the enzyme might be metalloprotein. SDS and metal ions such as Hg(2+), Zn(2+), Cu(2+), Ag(2+) and Fe(2+) decreased the lipase activity remarkedly. Its marked stability and activity in organic solvents suggest that this lipase is highly suitable as a biotechnological tool with a variety of applications including organo synthetic reactions and preparation of enantiomerically pure pharmaceuticals. The Km and Vmax value of the purified enzyme for triolein hydrolysis were calculated to be 1.11 mmol/L and 0.05 mmol/L/min respectively.