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1.
Indian J Surg ; 77(Suppl 1): 79-80, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25972653

RESUMO

Femoral hernias are elusive conditions that, despite having life-threatening complications, are often undiagnosed in asymptomatic patients. They are less common than inguinal hernias and occur more frequently in females [Purushotham et al. (2014) J Evol Med Dent Sci 3(05):1160-1163]. In the first place, femoral hernia in a male patient is itself, a very rare clinical presentation, let alone complications like obstruction or strangulation in the second place. Thus, despite the fact that femoral hernias account for only 2-4 % of all groin hernias, their timely and correct diagnosis is vital due to the increased mortality associated with emergency surgery for their complications [Arkoulis et al. (2012) Ox J Med, J Surg Case Rep 2012(6):6]. This, however, is not always easy, where mortality has been found to be tenfold. Here, we present a case of right-sided obstructed femoral hernia of Richter's variety in a male of 52 years of age.

2.
Cell Death Dis ; 3: e402, 2012 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-23059821

RESUMO

DAMTC (7,8-diacetoxy-4-methylcoumarin) is a thioderivative of 4-methyl coumarin, and previously we have shown that DAMTC is a potent inhibitor of cell growth and an inducer of apoptosis in non-small cell lung cancer (A549) cells. It induces apoptosis through mitochondrial pathway by modulating NF-κB, mitogen-activated protein kinase (MAPK) and p53 pathways. Herein, we explored the genome-wide effects of DAMTC in A549 cells using the concerted approach of transcriptomics and proteomics. In addition to apoptotic pathways, which have been validated earlier, the bioinformatic analysis of microarray data identified small GTPase-mediated signal transduction among the significantly altered biological processes. Interestingly, we observed significant downregulation of some members of the Rho family GTPases in the proteomics data too. Downregulation of Rho GTPases (RhoGDIα (Rho GDP dissociation inhibitor-α, also known as ARHGDIA), Ras homolog family member A, Ras-related C3 botulinum toxin substrate 1 and cell division cycle 42) was validated by western blotting. The Rho protein family is implicated in maintaining the actin filament assembly and cell motility, and we also observed that DAMTC treatment causes actin cytoskeletal reorganization, promotes filopodia formation and inhibits cell motility in A549 cells. The effect of DAMTC treatment on cytoskeleton was reversed after the overexpression of RhoGDIα. In addition, DAMTC augmented the apoptotic effect of etoposide, a proapoptotic chemotherapeutic drug. This elucidation of the mechanism behind DAMTC-induced apoptosis and inhibition of cell motility in A549 cells may make it a potential therapeutic for lung cancer.


Assuntos
Movimento Celular/efeitos dos fármacos , Cumarínicos/farmacologia , Citoesqueleto/efeitos dos fármacos , Proteômica , Transcriptoma/efeitos dos fármacos , Actinas/metabolismo , Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Adenocarcinoma de Pulmão , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Cumarínicos/química , Citoesqueleto/metabolismo , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Proteínas Oncogênicas/genética , Proteínas Oncogênicas/metabolismo , Proteína Desglicase DJ-1 , Transdução de Sinais , Proteínas rho de Ligação ao GTP/metabolismo , Inibidor alfa de Dissociação do Nucleotídeo Guanina rho/genética , Inibidor alfa de Dissociação do Nucleotídeo Guanina rho/metabolismo
3.
Curr Med Chem ; 18(25): 3758-824, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21831039

RESUMO

Prunus is a genus of trees and shrubs, including the plums, cherries, peaches, apricots and almonds. Nearly five hundred seventy chemical compounds have so far been isolated from several Prunus species. This comprehensive review summarizes the isolation of chemical compounds reported during the period 1908 to June 2010. As per scrutiny of literature, we did not find any review on the chemistry or biology of genus Prunus or on the biological activities of its constituents. Extensive work has been done at the Department of Chemistry, University of Delhi by several groups on the isolation, identification, biological activity evaluation and synthesis of a large number of novel compounds from different Prunus species during the the last six decades (1940-2000), primarly by Seshadri, Nagarajan and Parmar et al. on P. domestica, P. cerasus, P. cerasoides, P. puddum and P. communis. This comprehensive review will benefit a large number of researchers in the fields of chemistry, botany, drug industries and pharmacology.


Assuntos
Extratos Vegetais/química , Extratos Vegetais/farmacologia , Prunus/química , Animais , Carotenoides/química , Carotenoides/isolamento & purificação , Carotenoides/farmacologia , Cumarínicos/química , Cumarínicos/isolamento & purificação , Cumarínicos/farmacologia , Flavonoides/química , Flavonoides/isolamento & purificação , Flavonoides/farmacologia , Humanos , Extratos Vegetais/isolamento & purificação , Esteroides/química , Esteroides/isolamento & purificação , Esteroides/farmacologia
4.
Curr Med Chem ; 18(25): 3929-51, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21824098

RESUMO

Coumarins, a well-known class of naturally occurring compounds, display a remarkable array of biochemical and pharmacological actions, some of which suggest that certain members of this group of compounds may significantly affect the function of various mammalian cellular systems. The development of coumarins as antioxidant agents has attracted much attention in recent years. Coumarins afford an opportunity for the discovery of new antioxidants with truly novel mechanisms of action. This review updates and expands the 2006 review by the same author. The review considers and incorporates the most recently published literature on coumarins as related to their antioxidant properties. A lot of coumarins have been identified from natural sources, especially green plants. These natural compounds have served as valuable leads for further design and synthesis of more active analogues. Beyond doubt, a deep understanding of the mechanisms of existing synthetic and natural coumarins will build the basis for the rational design.


Assuntos
Antioxidantes/química , Antioxidantes/farmacologia , Cumarínicos/química , Cumarínicos/farmacologia , Plantas/química , Animais , Humanos , Extratos Vegetais/química , Extratos Vegetais/farmacologia
5.
J Environ Sci Health B ; 45(6): 524-30, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20574873

RESUMO

Microwave irradiation (MWI) of acetophenones and substituted benzaldehydes in water resulted in a "green-chemistry" procedure for the preparation of chalcones (1-14), through base catalyzed Claisen-Schmidt condensation reaction, in good yields. Further 3,5-diaryl-6-carbethoxy-2-cyclohexen-1-ones (1a-14a) were prepared through base catalyzed cyclocondensation of above chalcones with ethylacetoacetate using MWI as the energy source and silica as support. Out of fourteen cyclohexenones, ten (1a, 4a, 5a, 6a, 7a, 9a, 10a, 11a, 12a and 13a) are reported for the first time in literature. The synthesized compounds were characterized using various spectroscopic techniques, viz. ((1)H NMR and IR) and screened for their antifungal activity in vitro against Sclerotium rolfsii and Rhizoctonia solani by poisoned food technique. The compounds tested were found to be active against R. solani whereas against S. rolfsii, moderate activity was observed, as evident from LC(50) values. The most potent compounds against R. solani were 1-(4-Fluoro-phenyl)-3-phenyl-propenone (13) and 1,3-Diphenyl-propenone (14) having LC(50) values of 2.36 and 2.49 mg L(- 1) respectively (LC(50) of Hexaconazole = 1.12 mg L(- 1)) and against S. rolfsii 3-(4-Fluoro-phenyl)-5-(3-nitro-phenyl)-6-carbethoxy-2-cyclohexen-1-one (12a) was most active having LC(50) value of 285 mg L(- 1)compared to Hexaconazole (LC(50) = 1.27 mg L(- 1)).


Assuntos
Antifúngicos/química , Antifúngicos/farmacologia , Basidiomycota/efeitos dos fármacos , Chalconas/química , Chalconas/farmacologia , Antifúngicos/síntese química , Chalconas/síntese química , Espectroscopia de Ressonância Magnética , Micro-Ondas , Relação Estrutura-Atividade
6.
Indian J Microbiol ; 50(4): 456-62, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22282615

RESUMO

Aspergillus terreus produces lipase 7.01 IU/ml in 96 h after optimization by one variable at a time method. Using the significant factors i.e. corn oil (A), sodium nitrate (B), casein (C), agitation rate (D) and incubation period (E) RSM was carried out resulting in 19.65 IU/ml from the combination +1(A), -1(B), -1(C), +1(D) and 0(E). The interactions between sodium nitrate, casein and agitation with corn oil were most significant. Scale up of production from 250 ml shake flask to 30 l bioreactor resulted in increased productivity of 0.52 IU/ml/h as against 0.2 IU/ml/h obtained in shake flasks. This lipase could carryout solvent free synthesis of partial glycerides of oleic acid with 96% efficiency in 12 h.

7.
Mycoses ; 52(3): 223-7, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-18793265

RESUMO

A dihydropyridine derivative, diethyl 4-(4-methoxyphenyl)-2,6-dimethyl-1,4-dihydropyridin-3,5-dicarboxylate (2e), having potent antifungal activity against pathogenic species of Aspergillus was investigated for its possible molecular mechanism of action. The SDS-PAGE coupled with nano-high-performance liquid chromatography-tandem mass spectrometry was used directly to assess both absolute abundance and differential expression of proteins in the secretory phases of Aspergillus fumigatus under the influence of 2e. It was observed that the compound inhibited the expression of two proteins of 60.99 and 79.77 kDa. Both of these secretory proteins that were inhibited by 2e, were analysed further by matrix assisted laser desorption ionization time-of-flight mass spectrometry. The 60.99- and 79.77-kDa proteins were identified as probable retroelement pol polyprotein and elongation factor G respectively. These targeted proteins could be the products of potentially virulence-related genes of A. fumigatus which may unravel the mode of action of 2e and pathobiology of A. fumigatus.


Assuntos
Antifúngicos/farmacologia , Aspergillus fumigatus/efeitos dos fármacos , Di-Hidropiridinas/farmacologia , Proteínas Fúngicas/genética , Expressão Gênica/efeitos dos fármacos , Aspergillus fumigatus/química , Aspergillus fumigatus/genética , Aspergillus fumigatus/metabolismo , Proteínas Fúngicas/química , Proteínas Fúngicas/metabolismo , Dados de Sequência Molecular , Peso Molecular
8.
Indian J Med Res ; 128(1): 13-21, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18820353

RESUMO

Acetylation is one of the most important post-translational modification of proteins determining the structure, function and intracellular localization that plays an important role in the signal transduction pathways related to diverse cell functions, both during unstimulated and stress conditions. Protein acetylation in cells is regulated by a co-ordinated action of histone acetyl transferases (HAT) and histone deacetylases(HDAC) that ensures the maintenance of homeostasis and execution of activities related to damage response viz. DNA repair, cell cycle delay, apoptosis and senescence. Since inhibition of histone deacetylation, stalls the progress of many nuclear events including proliferation and damage response events on the one hand and the levels of deacetylases are elevated in many tumours on the other. Histone deacetylase has been among the targets for the development of anticancer drugs and adjuvant. The recent observation showing acetylation of proteins by calreticulin (an endoplasmic reticulum resident protein) with a high efficiency when polyphenolic acetates are the acetyl group donating molecules and acetyl CoA as weak substrate extends the realm of protein acetylation beyond HAT/HDAC combination. Elucidation of the relative roles of HAT/HDAC mediated acetylation viz. a calreticulin mediated acetylation in cell function under a variety of stress conditions would hold key to the design of drugs targeting protein acetylation system.


Assuntos
Antineoplásicos/uso terapêutico , Histonas/metabolismo , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Transdução de Sinais/efeitos dos fármacos , Acetilação , Humanos
9.
Anticancer Agents Med Chem ; 8(2): 171-85, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18288920

RESUMO

Because invasion is, either directly or via metastasis formation, the main cause of death in cancer patients, development of efficient anti-invasive agents is an important research challenge. We have established a screening program for potentially anti-invasive compounds. The assay is based on organotypic confronting cultures between human invasive cancer cells and a fragment of normal tissue in three dimensions. Anti-invasive agents appeared to be heterogeneous with regard to their chemical nature, but plant alkaloids, polyphenolics and some of their synthetic congeners were well represented. Even within this group, active compounds were quite diverse: (+)-catechin, tangeretin, xanthohumol and other prenylated chalcones, 3,7-dimethoxyflavone, a pyrazole derivative, an isoxazolylcoumarin and a prenylated desoxybenzoin. The data gathered in this system are now applied in two projects. Firstly, structure-activity relationships are explored with computer models using an artificial neural network approach, based on quantitative structural descriptors. The aim of this study is the prediction and design of optimally efficient anti-invasive compounds. Secondly, the metabolism of orally ingested plant polyphenolics by colonic bacteria is studied in a simulator of the human intestinal microbial ecosystem (SHIME) and in human intervention trials. This method should provide information on the final bioavailability of the active compounds in the human body, with regard to microbial metabolism, and the feasibility of designing pre- or probiotics that increase the generation of active principles for absorption in the gastro-intestinal tract. The final and global aim of all these studies is to predict, synthesize and apply in vivo molecules with an optimal anti-invasive, and hence an anti-metastatic activity against cancer.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Flavonoides/farmacologia , Invasividade Neoplásica/prevenção & controle , Metástase Neoplásica/prevenção & controle , Neoplasias/tratamento farmacológico , Fenóis/farmacologia , Animais , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/metabolismo , Proliferação de Células/efeitos dos fármacos , Flavonoides/química , Flavonoides/metabolismo , Humanos , Estrutura Molecular , Fenóis/química , Fenóis/metabolismo , Plantas/química , Polifenóis
10.
Talanta ; 68(4): 1273-80, 2006 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-18970460

RESUMO

N,N,N',N'-tetraoctyl diglycolamide (TODGA) has been used as the stationary phase in the extraction chromatographic separation of actinides and other metal ions from pure nitric acid as well as from simulated high-level waste (SHLW). Chromosorb-W was found to be a better support material amongst the different solid supports evaluated viz. chromosorb-W, chromosorb-102, XAD-4 and XAD-7. Uptake profiles of various metal ions, such as U(VI), Pu(IV), Am(III), Eu(III), Fe(III), Sr(II) and Cs(I) were obtained as a function of acidity by batch studies using TODGA/chromosorb-W. Effect of macro concentration of Nd, Fe and U suggested that the uptake of Am(III) is mainly influenced by the presence of trivalent lanthanide ions. Breakthrough capacity of the resin material for Am(III) in presence of macro amount of Eu(III) was determined in the successive cycles of loading and elution. Loading capacity of the column was found to be 20mg of Eu/g of the resin material. Elution studies of Am(III) suggested that 0.01M EDTA was effective amongst different eluents used.

11.
Placenta ; 23(4): 352-7, 2002 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11969347

RESUMO

We have earlier established in tissues of several mammalian animal species the existence of a novel membrane bound enzyme termed 7,8-diacetoxy-4-methylcoumarin (DAMC): protein transacetylase (TAase) that possibly transfers acetyl groups from the model acetoxy drug (DAMC) to certain enzyme protein viz. glutathione S-transferase (GST), cytochrome P-450 and NADPH cytochrome C reductase leading to the drastic modulation of their catalytic activities. We have in this report extended the studies to human tissue and characterized TAase from placenta. For this purpose placental microsomes were preincubated with DAMC along with the receptor protein (cytosolic GST) followed by the addition of the substrates of GST in order to quantify the catalytic activity of GST, the extent of inhibition of GST served as a measure of TAase. Placental TAase was also found to irreversibly activate NADPH cytochrome C reductase by DAMC. Placental enzyme activated the reductase even at very low concentration of DAMC. Iodoacetamide nearly abolished the placental TAase suggesting the presence of active thiol group in the enzyme and the TAase demonstrated hyperbolic kinetics. Kinetic constants obtained by varying the concentrations of either of the substrates DAMC or cytosolic GST characterized TAase catalysed reaction as the bimolecular reaction. Further studies are in progress to delineate the physiological importance of TAase in placenta.


Assuntos
Acetiltransferases/metabolismo , Cumarínicos/metabolismo , Glutationa/metabolismo , Placenta/enzimologia , Adulto , Animais , Feminino , Glutationa Transferase/metabolismo , Humanos , Técnicas In Vitro , Cinética , Masculino , Camundongos , Microssomos/enzimologia , NADPH-Ferri-Hemoproteína Redutase/metabolismo , Gravidez , Ratos , Ratos Wistar , Especificidade por Substrato
12.
Bioorg Med Chem ; 9(10): 2643-52, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11557352

RESUMO

The chemo- and enantioselective capabilities of porcine pancreatic lipase (PPL) in tetrahydrofuran, and Candida rugosa lipase (CRL) in diisopropyl ether have been investigated for the acetylation of racemic 2-alkyl/aryl-3-hydroxypropiophenones, which are important precursors in the synthesis of biologically active chromanones and isoflavanones. A highly chemoselective acetylation of primary hydroxy group in preference to phenolic hydroxy group leading to the formation of enantiomerically enriched monoacetates has been observed.


Assuntos
Candida/enzimologia , Hidroxipropiofenona/metabolismo , Lipase/metabolismo , Acetatos/química , Acetilação , Animais , Catálise , Cromanos/química , Cromatografia Líquida de Alta Pressão , Cristalografia por Raios X , Hidroxilação , Hidroxipropiofenona/análogos & derivados , Hidroxipropiofenona/química , Isoflavonas/química , Espectroscopia de Ressonância Magnética , Modelos Químicos , Conformação Molecular , Estrutura Molecular , Pâncreas/enzimologia , Estereoisomerismo , Relação Estrutura-Atividade , Especificidade por Substrato , Suínos
13.
Bioorg Med Chem Lett ; 11(16): 2117-21, 2001 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-11514151

RESUMO

(+/-)-5-Acetoxy-3-(4-fluorophenyl)-2-phenylisoxazolidine has been synthesised by a highly diastereoselective [3+2] cycloaddition reaction between alpha-(4-fluorophenyl)-N-phenylnitrone and vinyl acetate in good yield. Candida rugosa lipase catalyses the deacetylation of this (+/-)-5-acetoxyisoxazolidine in a highly enantioselective fashion in diisopropyl ether containing n-butanol affording (-)-5-acetoxy-3-(4-fluorophenyl)-2-phenylisoxazolidine in 43% yield and >99% ee.


Assuntos
Isoxazóis/metabolismo , Lipase/metabolismo , Acetilação , Animais , Catálise , Conformação Molecular , Suínos
14.
Mutat Res ; 494(1-2): 31-40, 2001 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-11423343

RESUMO

The ability of various acetoxy derivatives of 4-methylcoumarins to inhibit the genotoxic changes due to aflatoxin B(1) (AFB(1)) is reported here. Several 4-methylcoumarins (test compounds), such as 7,8-diacetoxy-4-methylcoumarin (DAMC), monoacetoxy-4-methylcoumarin (MAC), 5-N-acetyl-6-acetoxy-4-methylcoumarin (NAMC) and 7,8-dihydroxy-4-methylcoumarin (DHMC) were separately administered intraperitoneally (i.p.) to male wistar rats followed by AFB(1) administration i.p. or intratracheally (i.t.) (2-8 mg/kg b.wt.) and another dose of the test compound. The animals were sacrificed 26h after AFB(1) administration. From animals receiving AFB(1) i.p., bone marrow (BM) cells were isolated and stained with Mayer's haematoxylin and eosin. Micronuclei (MN) in BM were scored by light microscopy. From animals receiving AFB(1) i.t., bronchoalveolar lavage (BAL) was obtained, lung cells (LG) were isolated and stained with fluorochrome 6-diamidino-2-phenylindole (DAPI) for the analysis of MN, apoptotic bodies (AP) and cell cycle variations. Rats were separately treated with the vehicle DMSO to serve as the proper control. AFB(1) caused significant dose-dependent induction of MN in BM as well as LG. AP were observed in LG of rats receiving AFB(1) and was found to correlate with MN induction. DAMC injection caused significant decrease in AP due to AFB(1) in LG and MN in both BM and LG. The effectiveness of MAC was approximately half that of DAMC, thereby indicating that number of acetoxy groups on the coumarin molecule determine the efficacy. The fact that NAMC had no effect either on MN or AP indicate that neither acetoxy group at C-6 nor the N-acetyl group at C-5 facilitate the transfer of acetyl group to P-450 required for inhibition of AFB(1)-epoxidation. DHMC, the deacetylated product of DAMC had no normalizing effect on the induction of MN and AP. These findings confirm our earlier hypothesis that DAMC-mediated acetylation of microsomal P-450 (catalysing epoxidation of AFB(1)) through the action of microsomal transacetylase is responsible for the protective action of DAMC. The relative number and position of acetoxy groups on the coumarin nucleus determine the specificity to the transacetylase necessary for the chemopreventive action.


Assuntos
Aflatoxina B1/toxicidade , Antimutagênicos/farmacologia , Cumarínicos/farmacologia , Mutagênicos/toxicidade , Acetilação , Animais , Apoptose , Células da Medula Óssea/efeitos dos fármacos , Sistema Enzimático do Citocromo P-450/metabolismo , Pulmão/citologia , Pulmão/efeitos dos fármacos , Masculino , Testes para Micronúcleos , Ratos , Ratos Wistar , Relação Estrutura-Atividade
15.
Bioorg Med Chem ; 9(5): 1085-9, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11377166

RESUMO

Our earlier work established a convenient assay procedure for acetoxycoumarin (AC): protein transacetylase (TA) by indirectly quantifying the activity of glutathione (GSH)-S-transferase (GST), the extent of inhibition of GST under the conditions of the assay represented TA activity. In this communication, we have probed the specificity for TA with respect to the number and position of acetoxy groups on the benzenoid as well as the pyranone rings of the coumarin system governing the efficient transfer of acetyl groups to the protein(s). For this purpose, coumarins bearing one acetoxy group, separately at C-3 or C-4 position and 4-methylcoumarins bearing single acetoxy group, separately at C-5, C-6 or C-7 position were synthesized and specificities to rat liver microsomal TA were examined. Negligible TA activity was discernible with 3-AC as the substrate, while the substrate efficiency of other AC were in the order 7-acetoxy-4-methylcoumarin (7 AMC)>6 AMC>5 AMC=5 ADMC=4 AC. To achieve a comparable level of GST inhibition which was proportional to the enzymatic transfer of acetyl groups to the protein (GST), the concentrations of 7-AMC, 6-AMC, 5-AMC and 4-AC were in the order 1:2:4:4, respectively. One diacetoxycoumarin, i.e., 7,8-diacetoxy-4-methylcoumarin (DAMC) was also examined and it was found to elicit maximum level of GST inhibition, nearly twice that observed with 7-AMC. These observations lead to the logical conclusion that a high degree of acetyl group transfer capability is conferred when the acetoxy group on the benzenoid ring of the coumarin system is in closer proximity to the oxygen heteroatom, i.e., when the acetoxy groups are at the C-7 and C-8 positions.


Assuntos
Benzopiranos/química , Benzopiranos/metabolismo , Cumarínicos/síntese química , Glutationa Transferase/metabolismo , NADPH-Ferri-Hemoproteína Redutase/metabolismo , Umbeliferonas/síntese química , Aflatoxina B1/química , Animais , Benzopiranos/farmacologia , Cumarínicos/química , Cumarínicos/metabolismo , Cumarínicos/farmacologia , DNA/química , Ativação Enzimática/efeitos dos fármacos , Ativação Enzimática/fisiologia , Glutationa Transferase/antagonistas & inibidores , Microssomos Hepáticos , Oxigênio/química , Oxigênio/metabolismo , Ratos , Ratos Wistar , Relação Estrutura-Atividade , Especificidade por Substrato/fisiologia , Umbeliferonas/metabolismo , Umbeliferonas/farmacologia
16.
Bioorg Med Chem ; 9(5): 1345-8, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11377191

RESUMO

An efficient lipase catalysed synthesis of optically enriched alpha-halogenated amides with concomitant optical enrichment of the starting alpha-haloesters is described. Candida antarctica lipase (CAL) was found to be a better catalyst over porcine pancreatic lipase (PPL) and Candida cylindracea lipase (CCL). The effect of different organic solvents was also studied.


Assuntos
Aminas/síntese química , Candida/enzimologia , Lipase/metabolismo , Aminas/química , Animais , Benzilaminas/química , Benzilaminas/metabolismo , Catálise , Cicloexilaminas/química , Cicloexilaminas/metabolismo , Éteres/farmacologia , Proteínas Fúngicas/efeitos dos fármacos , Proteínas Fúngicas/metabolismo , Lipase/efeitos dos fármacos , Pancrelipase/metabolismo , Solventes/farmacologia , Estereoisomerismo , Suínos
17.
J Appl Microbiol ; 90(4): 609-13, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11309073

RESUMO

AIMS: The present study was carried out to assess the potential of Fusarium globulosum lipase (FGL) for chemoselective and regioselective biotransformations for the synthesis of industrially important organic compounds. METHODS AND RESULTS: Different acetylation/deacetylation reactions and ester synthesis reactions were carried out in organic media. Fusarium globulosum lipase showed exclusive selectivity for the acetylation of the alcoholic hydroxyl group over the phenolic hydroxyl group of the hydroxymethylated phenols and aryl alkyl ketones. This also led to the enantiomeric resolution of the aryl alkyl ketone. In contrast, the lipase showed reversed selectivity in deacetylation where it preferred the phenolic acetoxy group over the alcoholic acetoxy moiety of the peracetates of hydroxymethylated compounds. The enzyme also exhibited strict regioselection for deacetylation at the para position of the peracetate of an aryl alkyl ketone. In addition, the lipase also synthesized a variety of industrially important fatty acid esters of sugars, sugar alcohols, alcohols and ascorbic acid with high preference for middle-chain fatty acids. CONCLUSION: Fusarium globulosum lipase shows versatile catalytic potential in terms of chemo-, enantio- and regioselectivity and fatty acid specificity in carrying out a variety of industrially important biotransformations. SIGNIFICANCE AND IMPACT OF THE STUDY: The biocatalytic potential of FGL can thus be utilized for the synthesis and modification of different types of polyphenolic compounds and esters. These compounds find widespread uses as surfactants, bioactive analogues, antioxidants and flavour components in the food, detergent, pharmaceutical and cosmetic industries.


Assuntos
Ésteres/metabolismo , Flavonoides , Fusarium/enzimologia , Lipase/metabolismo , Acetilação , Álcoois/metabolismo , Ácido Ascórbico/metabolismo , Biotransformação , Metabolismo dos Carboidratos , Catálise , Cetonas/metabolismo , Fenóis/metabolismo , Polímeros/metabolismo , Polifenóis
18.
Bioorg Med Chem ; 9(2): 337-45, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11249126

RESUMO

Fourteen novel C-prenylated and O-allylated 1,3-diarylpropenones (chalcones) were synthesized by Claisen-Schmidt condensation reaction of C-prenylated/O-allylated acetophenones with appropriate aldehydes; twelve of these model chalcones were screened in an assay based on the confrontation of invasive human MCF-7/6 mammary carcinoma cells with fragments of normal embryonic chick heart in vitro. Out of the twelve chalcones tested, three were found to exhibit potent anti-invasive activity. Some of these chalcones and their precursor acetophenones were also tested for inhibition of initiation of lipid peroxidation in rat liver microsomes; a prenylated acetophenone carrying two methoxy groups and two free phenolic hydroxy functions was found to be a potential antioxidant.


Assuntos
Antineoplásicos/síntese química , Chalcona/farmacologia , Invasividade Neoplásica/prevenção & controle , Acetofenonas/farmacologia , Animais , Antineoplásicos/farmacologia , Antioxidantes/síntese química , Antioxidantes/farmacologia , Neoplasias da Mama/patologia , Chalcona/síntese química , Embrião de Galinha , Técnicas de Cocultura , Técnicas de Química Combinatória , Avaliação Pré-Clínica de Medicamentos , Feminino , Humanos , Peroxidação de Lipídeos/efeitos dos fármacos , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/metabolismo , Miocárdio/citologia , Ratos , Relação Estrutura-Atividade , Células Tumorais Cultivadas/efeitos dos fármacos
19.
Teratog Carcinog Mutagen ; 21(2): 181-7, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11223895

RESUMO

Our earlier studies documented the ability of 7,8-diacetoxy-4-methylcoumarin (DAMC) to cause irreversible inhibition of cytochrome P-450 linked mixed function oxidases (MFO) mediated by membrane bound DAMC: protein transacetylase. Since P-450 catalyzed oxidation of benzene is crucial to its toxic effects, the action of DAMC and related analogues were considered promising in preventing the genotoxicity due to benzene. For this purpose rats were pretreated with various acetoxy-4-methylcoumarins (test compounds), which was followed by the administration of benzene either intratracheally (IT) or intraperitoneally (IP), and sacrificed 26 h after the injection of benzene. The incidence of micronuclei (MN) in bone marrow (BM) and lung (LG) were assessed by light and fluorescent microscopy, respectively. A dose-dependent induction of MN in BM and LG cells was observed in rats administered with benzene. A significant reduction in benzene-induced MN in BM and LG was observed as a result of DAMC administration to rats; a higher dose of DAMC resulted in greater inhibition of clastogenic action of benzene as revealed by MN incidence. 7,8-dihydroxy-4-methylcoumarin (DHMC), the deacetylated product of DAMC, demonstrated relatively lesser potency to inhibit the clastogenic action of benzene. This observation is consistent with the ability of DAMC to inhibit the formation of benzene oxide as well as to scavenge the oxygen radicals formed during the course of benzene metabolism. The fact that DHMC can only scavenge the oxygen radicals and is ineffective in inhibiting benzene oxidation in vivo explains the reduced capability of dihydroxy coumarin to prevent MN due to benzene. 7-Acetoxy-4-methylcoumarin (MAC) inhibits the MN due to benzene being roughly 50% of that produced by DAMC. DAMC is also effective in normalizing the cell cycle alterations produced by benzene in BM and LG. These observations further substantiate our hypothesis that the biological effects of acetoxy coumarins are mediated by the action of membrane bound transacetylase that catalyzes the acetylation of concerned proteins. Teratogenesis Carcinog. Mutagen. 21:181-187, 2001.


Assuntos
Benzeno/efeitos adversos , Medula Óssea/efeitos dos fármacos , Cumarínicos/metabolismo , Ciclopentanos/metabolismo , Pulmão/efeitos dos fármacos , Micronúcleos com Defeito Cromossômico/efeitos dos fármacos , Mutagênicos , Animais , Benzeno/metabolismo , Células da Medula Óssea/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Relação Dose-Resposta a Droga , Masculino , Testes para Micronúcleos , Microscopia de Fluorescência , Ratos , Ratos Wistar , Umbeliferonas/metabolismo
20.
Bioorg Med Chem ; 8(1): 233-7, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10968282

RESUMO

The existence of a novel microsomal deacetylase in rat liver catalysing deacetylation of diacetoxy 4-methylcoumarins has been reported. A simple method is outlined for the enzyme assay based upon the quantification of the dihydroxy derivative by measuring the UV absorption of its complex with ADP and Fe3+ at 600 nm. The enzyme can be routinely assayed using 7,8-diacetoxy-4-methylcoumarin (DAMC) as the substrate and demonstrated hyperbolic kinetics and yielded Km and vmax values of 1250 microM and 500 units, respectively. The pH optima was found to be 7.5 for the enzyme. No DAMC deacetylase activity was found in hepatic cytosol and the enzyme activity was not discernible in extrahepatic tissues.


Assuntos
Acetilesterase/metabolismo , Benzopiranos/metabolismo , Hidrolases de Éster Carboxílico/metabolismo , Cumarínicos/metabolismo , Microssomos Hepáticos/enzimologia , Animais , Benzopiranos/química , Concentração de Íons de Hidrogênio , Hidrólise , Cinética , Masculino , Ratos , Ratos Wistar , Especificidade por Substrato
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