Anti-Cancer Effects of Synergistic Drug-Bacterium Combinations on Induced Breast Cancer in BALB/c Mice

Cancer development and progression are extremely complex due to the alteration of various genes and pathways. In most cases, multiple agents are required to control cancer progression. The purpose of this study is to investigate, using a mouse model, the synergistic interactions of anti-cancer agents, 1'-S-1'-acetoxychavicol acetate (ACA), Mycobacterium indicus pranii (MIP), and cisplatin (CDDP) in double and triple combinations to treat chemo-sensitize and immune-sensitize breast cancer. Changes in tumor volume and body weight were monitored. Organs were harvested and stained using hematoxylin-eosin for histopathological assessment. Milliplex enzyme-linked immunosorbent assay (ELISA) was performed to determine cytokine levels, while immunohistochemistry (IHC) was conducted on tumor biopsies to verify systemic drug effects. In vivo mouse models showed tumor regression with maintenance of regular body weight for all the different treatment regimens. IHC results provided conclusive evidence indicating that combination regimens were able to down-regulate nuclear factor kappa-B activation and reduce the expression of its regulated pro-inflammatory proteins. Reduction of pro-inflammatory cytokines (e.g., IL-6, TNF-α, and IFN-ɣ) levels were observed when using the triple combination, which indicated that the synergistic drug combination was able to significantly control cancer progression. In conclusion, ACA, MIP, and CDDP together serve as promising candidates for further development and for subsequent clinical trials against estrogen-sensitive breast cancer.

Resorcinol-, catechol- and saligenin-based bronchodilating β2-agonists as inhibitors of human cholinesterase activity

We investigated the influence of bronchodilating β2-agonists on the activity of human acetylcholinesterase (AChE) and usual, atypical and fluoride-resistant butyrylcholinesterase (BChE). We determined the inhibition potency of racemate and enantiomers of fenoterol as a resorcinol derivative, isoetharine and epinephrine as catechol derivatives and salbutamol and salmeterol as saligenin derivatives. All of the tested compounds reversibly inhibited cholinesterases with Ki constants ranging from 9.4 μM to 6.4 mM and had the highest inhibition potency towards usual BChE, but generally none of the cholinesterases displayed any stereoselectivity. Kinetic and docking results revealed that the inhibition potency of the studied compounds could be related to the size of the hydroxyaminoethyl chain on the benzene ring. The additional π-π interaction of salmeterol's benzene ring and Trp286 and hydrogen bond with His447 probably enhanced inhibition by salmeterol which was singled out as the most potent inhibitor of all the cholinesterases.

Anti-proliferative, apoptotic induction, and anti-migration effects of hemi-synthetic 1'S-1'-acetoxychavicol acetate analogs on MDA-MB-231 breast cancer cells

Nine analogs of 1'S-1'-acetoxychavicol acetate (ACA) were hemi-synthesized and evaluated for their anticancer activities against seven human cancer cell lines. The aim of this study was to investigate the anti-proliferative, apoptotic, and anti-migration effects of these compounds and to explore the plausible underlying mechanisms of action. We found that ACA and all nine analogs were non toxic to human mammary epithelial cells (HMECs) used as normal control cells, and only ACA, 1'-acetoxyeugenol acetate (AEA), and 1'-acetoxy-3,5-dimethoxychavicol acetate (AMCA) inhibited the growth of MDA-MB-231 breast cancer cells with a half-maximal inhibitory concentration (IC50) value of <30.0 μM based on 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay results, and were selected for further investigation. DNA fragmentation assays showed that these three compounds markedly induced apoptosis of MDA-MB-231 cells. Western blot analysis revealed increased expression levels of cleaved PARP, p53, and Bax, while decreased expression levels of Bcl-2 and Bcl-xL were seen after treatment, indicating that apoptosis was induced via the mitochondrial pathway. Moreover, ACA, AEA, and AMCA effectively inhibited the migration of MDA-MB-231 cells. They also downregulated the expression levels of pFAK/FAK and pAkt/Akt via the integrin β1-mediated signaling pathway. Collectively, ACA and its hemi-synthetic analogs, AEA and AMCA are seen as potential anticancer agents following their abilities to suppress growth, induce apoptosis, and inhibit migration of breast cancer cells.

Single-Electron Transmetalation: Protecting-Group-Independent Synthesis of Secondary Benzylic Alcohol Derivatives via Photoredox/Nickel Dual Catalysis

Protecting-group-independent cross-coupling of α-alkoxyalkyl- and α-acyloxyalkyltrifluoroborates with aryl and heteroaryl bromides is achieved through application of photoredox/nickel dual catalysis. Reactions occur under exceptionally mild conditions, with outstanding functional group compatibility and excellent observed tolerance of heteroarenes. This method offers expedient access to protected secondary benzylic alcohol motifs bearing benzyl, pivaloyl, and N,N-diisopropylcarbamoyl protecting groups.

Asymmetric synthesis of tertiary benzylic alcohols

Vinyl, aryl, and alkynyl organometallics add to ketones containing a stereogenic sulfoxide. Tertiary alcohols are generated in diastereomerically and enantiomerically pure form. Reductive lithiation converts the sulfoxide into a variety of useful functional groups.

Efficient and selective reduction protocols of the 2,2-dimethyl-1,3-benzodioxan-4-one functional group to readily provide both substituted salicylaldehydes and 2-hydroxybenzyl alcohols

Two complementary procedures have been developed that selectively allow for the synthesis of either substituted salicylaldehydes or the corresponding 2-hydroxylbenzyl alcohols upon treatment of the 2,2-dimethyl-1,3-benzodioxan-4-one functional group with DIBAL-H or LAH, respectively.

Surfactant-Type Brønsted Acid Catalyzed Dehydrative Nucleophilic Substitutions of Alcohols in Water

A protocol for the dehydrative nucleophilic substitution of benzyl alcohols with a variety of carbon- and heteroatom-centered nucleophiles using dodecylbenzenesulfonic acid (DBSA) as a surfactant-type Brønsted acid catalyst in water has been developed. The reaction system can be applied to the stereoselective C-glycosylation of 1-hydroxy sugars in water. [reaction: see text].

Kinetics of Synthesizing Polymer-Supported Quaternary Ammonium Catalysts

This study attempted to synthesize the optimum quaterary ammonium poly(styrene-co-methylstyrene) catalyst using the combinatorial chemistry method. The catalyst was synthesized by a mix-split method. A phase-transfer catalyst library with 25 kinds of polystyrene-supported quaternary ammonium salt catalyst was the the result of the reaction of five kinds of chloromethylated crosslinked polystyrene with five tert-amines. The allylation of phenol and the oxidation of benzyl alcohol were used as the probing reaction to screen out the most active catalyst for the reaction using the iterative deconvolution method. The screening conditions included teritary amine and organic solvent. The structure of the most active catalyst in the allylation of phenol shows 20 mol % ring substitution and 0.177-0.25-mm pellet size activated with trihexylamine. For oxidation of benzyl alcohol, the reaction conditions of the most active catalyst included a resin of 20% ring substitution and pellet size of 0.177-0.25 mm, activated with triethylamine reacting in an organic solvent of n-hexane.

Chemoenzymatic dynamic kinetic resolution of rac-1-phenylethanol in ionic liquids and ionic liquids/supercritical carbon dioxide systems

Continuous dynamic kinetic resolution processes in different ionic liquid/supercritical carbon dioxide biphasic systems were carried out by simultaneously using both immobilized Candida antarctica lipase B (Novozym 435) and silica modified with benzenosulfonic acid (SCX) catalysts at 40 degrees C and 10 MPa. SCX was seen to act as an efficient heterogeneous chemical catalyst for the racemization of (S)-1-phenylethanol in different ionic liquid media ([emim][NTf(2)], [btma][NTf(2)] and [bmim][PF(6)]). Coating both chemical and enzymatic catalysts with ILs greatly improved the efficiency of the process, providing a good yield (76%) of (R)-1-phenylethyl propionate product with excellent enantioselectivity (ee = 91-98%) in continuous operation.

An efficient total synthesis and absolute configuration determination of varitriol

The first total synthesis and the absolute configuration determination of varitriol are described.

Triarylborane Ammonia Complexes as Ideal Precursors for Arylzinc Reagents in Asymmetric Catalysis

[reaction: see text] The value of arylboranes as precursors for arylzinc reagents in asymmetric catalysis is demonstrated. Kinetic studies on the transmetalation reaction with zinc reagents rationalize the observed differences of three classes of arylboranes in catalytic applications. By using the stable and easily accessible triarylborane ammonia complexes, an array of chiral diarylmethanols in high yield and enantioselectivity was synthesized.

Regio- and Stereoselective Ring Opening of 2,3-Diaryl Oxiranes by LiBr/Amberlyst 15: A New Stereocontrolled Access to 1,2-Diaryl-2-bromo Alcohols

Both symmetrical and nonsymmetrical trans-2,3-diaryloxiranes are regio- and stereoselectively opened by the LiBr/Amberlyst 15 system. In the case of symmetrical trans-stilbene oxide, the syn- versus anti-bromohydrins ratio ranged between 88/12 and 30/70, by varying the reaction temperature from 20 to -30 degrees C. In the case of nonsymmetrical para-substituted trans-2,3-diaryloxiranes, the regioselectivity is determined by electronic effects. If one phenyl bears a strong electron-withdrawing group (as NO2 or CF3), the nucleophilic attack is totally on the beta-carbon with respect to the substituted phenyl ring. With one phenyl bearing a strong electron-releasing group (OCH3), the regioselectivity is reversed. Ab initio calculation at the DFT/B3LYP/6-31G level, run on protonated epoxide structures, supports the formation of a cationic acyclic intermediate. Application of the method on ortho-methoxy and ortho-nitro 2,3-diaryloxiranes afforded the syn-bromohydrins in excellent yield, via regio- and stereoselective opening at either alpha- or beta-carbon, respectively.

Photochemical reaction mechanisms of 2-nitrobenzyl compounds: 2-nitrobenzyl alcohols form 2-nitroso hydrates by dual proton transfer

Irradiation of 2-nitrobenzyl alcohol (1, R = H) and 1-(2-nitrophenyl)ethanol (1, R = Me) in various solvents yields 2-nitroso benzaldehyde (4, R = H) and 2-nitroso acetophenone (4 R = Me), respectively, with quantum yields of about 60%. The mechanism of this reaction, known since 1918, was investigated using laser flash photolysis, time-resolved infrared spectroscopy (TRIR), and 18O-labeling experiments. The primary aci-nitro photoproducts 2 react by two competing paths. The balance between the two depends on the reaction medium. Reaction via hydrated nitroso compounds 3 formed by proton transfer prevails in aprotic solvents and in aqueous acid and base. In water, pH 3-8, the classical mechanism of cyclization to benzisoxazolidine intermediates 5, followed by ring opening to carbonyl hydrates 6, predominates. The transient intermediates 3 and 6 were identified by TRIR. Potential energy surfaces for these reactions were mapped by density functional calculations.

Optimization of Enzymatic Gas-Phase Reactions by Increasing the Long-Term Stability of the Catalyst

Enzymatic gas-phase reactions are usually performed in continuous reactors, and thus very stable and active catalysts are required to perform such transformations on cost-effective levels. The present work is concerned with the reduction of gaseous acetophenone to enantiomerically pure (R)-1-phenylethanol catalyzed by solid alcohol dehydrogenase from Lactobacillus brevis (LBADH), immobilized onto glass beads. Initially, the catalyst preparation displayed a half-life of 1 day under reaction conditions at 40 degrees C and at a water activity of 0.5. It was shown that the observed decrease in activity is due to a degradation of the enzyme itself (LBADH) and not of the co-immobilized cofactor NADP. By the addition of sucrose to the cell extract before immobilization of the enzyme, the half-life of the catalyst preparation (at 40 degrees C) was increased 40 times. The stabilized catalyst preparation was employed in a continuous gas-phase reactor at different temperatures (25-60 degrees C). At 50 degrees C, a space-time yield of 107 g/L/d was achieved within the first 80 h of continuous reaction.

Simultaneous synthesis of enantiomerically pure (R)-1-phenylethanol and (R)-alpha-methylbenzylamine from racemic alpha-methylbenzylamine using omega-transaminase/alcohol dehydrogenase/glucose dehydrogenase coupling reaction

A simultaneous synthesis of (R)-1-phenylethanol and (R)-alpha-methylbenzylamine from racemic alpha-methylbenzylamine was achieved using an omega-transaminase, alcohol dehydrogenase, and glucose dehydrogenase in a coupled reaction. Racemic alpha-methylbenzylamine (100 mM) was converted to 49 mM (R)-1-phenylethanol (> 99% ee) and 48 mM (R)-alpha-methylbenzylamine (> 98% ee) in 18 h at 37 degrees C. This method was also used to overcome product inhibition of omega-TA by the ketone product in the kinetic resolution of racemic amines at high concentration.

De novo design and utilization of photolabile caged substrates as probes of hydrogen tunneling with horse liver alcohol dehydrogenase at sub-zero temperatures: a cautionary note

In order to understand the influence of protein dynamics on enzyme catalysis and hydrogen tunneling, the horse liver alcohol dehydrogenase (HLADH) catalyzed oxidation of benzyl alcohol was studied at sub-zero temperatures. Previous work showed that wild type HLADH has significant kinetic complexity down to -50 degrees C due to slow binding and loss of substrate [S.-C. Tsai, J.P. Klinman, Biochemistry, 40 (2001) 2303]. A strategy was therefore undertaken to reduce kinetic complexity at sub-zero temperatures, using a photolabile (caged) benzyl alcohol that prebinds to the enzyme and yields the active substrate upon photolysis. By computer modeling, a series of caged alcohols were designed de novo, synthesized, and characterized with regard to photolysis and binding properties. The o-nitrobenzyl ether 15, with a unique long tail, was found to be most ideal. At sub-zero temperatures in 50% MeOH, a two-phase kinetic trace and a rate enhancement by the use of 15 were observed. Despite the elimination of substrate binding as a rate-limiting step, the use of caged benzyl alcohol does not produce a measurable H/D kinetic isotope effect. Unexpectedly, the observed fast phase corresponds to multiple enzyme turnovers, based on the stoichiometry of the substrate to enzyme. Possible side reactions and their effects, such as the re-oxidation of bound NADH and the dissipation of photo-excitation energy, may offer an explanation for the observed multiple-turnovers. The lack of observable deuterium isotope effects offers a cautionary note for the application of caged substrates to isolate and study chemical steps of enzyme reactions, particularly when NADH is involved in the reaction pathway.

Copper ion-induced activation and asymmetric benzoylation of 1,2-diols: kinetic chiral molecular recognition

New catalytic ability of copper(II) ion has been exploited for monobenzoylation of 1,2-diols. The catalyst can be readily modified by ligation to acquire higher stereoselectivity. Highly effective kinetic resolution of dl-1,2-diols was achieved. The enantiodiscrimination process was clearly shown to be controlled by the kinetics of acylation of dl-1,2-diols. The catalytic method was successfully applied to asymmetric desymmetrization of meso-hydrobenzoin.

A mild deprotection strategy for allyl-protecting groups and its implications in sequence specific dendrimer synthesis

A mild deprotection strategy for allyl ethers under basic conditions in the presence of a palladium catalyst is described. Under these conditions, aryl allyl ethers can be cleaved selectively in the presence of alkyl allyl ethers. These conditions are also effective in the deprotection of allyloxycarbonyl groups. The utility of the current methodology in sequence specific dendrimer synthesis is demonstrated.

Catalyzed asymmetric aryl transfer reactions to aldehydes with boronic acids as aryl source

Chiral diaryl methanols are important intermediates for the synthesis of biologically active compounds. Here, we describe a flexible method for their catalyzed asymmetric synthesis from readily available starting materials. Noteworthy is the fact that with a single catalyst both enantiomers of the product are accessible simply by choosing the appropriate combination of aryl boronic acid or aldehyde as aryl donor and acceptor, respectively. The catalysis with a planar-chiral ferrocene is easy to perform and yields a broad range of products with excellent enantioselectivities (up to 98% ee).

Asymmetric catalysis of hetero-ene reactions with tridentate Schiff base chromium(III) complexes

Tridentate Schiff base chromium(III) complex 1 catalyzes the asymmetric hetero-ene reaction between aryl aldehydes and either 2-methoxypropene or 2-trimethylsilyloxypropene to provide a series of beta-hydroxyenol ether products in high yields and enantioselectivities. X-ray crystallographic analysis of a closely related chromium complex reveals a bridged, dimeric structure bearing aquo-bound six-coordinate Cr(III) centers. A mechanism is proposed wherein water dissociation is effected by means of a chemical desiccant (BaO or silyl enol ether), thereby revealing the site for aldehyde complexation.

Analysis of conformational states of Candida rugosa lipase in solution: implications for mechanism of interfacial activation and separation of open and closed forms

In this study, an analysis of the transition between the inactive ("closed") and active ("open") conformations of Candida rugosa lipase in solution is performed using irreversible enzyme inhibitors, cyclic saligenin phosphates. It is shown that >90% inhibition of the enzyme activity toward water-soluble substrates (esterolytic activity) can be achieved with as little as 0.3 mol of the inhibitor per mole of enzyme, whereas activity toward emulsified substrates decreases by approximately 20% under the same conditions. It is also shown that short-term exposure of this inhibited enzyme preparation to an interface leads to a significant increase in esterolytic activity, which even exceeds that of the untreated control. These experimental observations suggest that the inhibitors interact predominantly, if not exclusively, with the open form of the enzyme and that any transitions occurring between the two conformers of the enzyme in solution, in the absence of an interface, are extremely slow. This conclusion is verified by separating the open and closed forms of the enzyme by hydrophobic interaction column chromatography on phenyl-sepharose. Fractions enriched with the respective conformations of the enzyme are further purified using gel-permeation chromatography. On the basis of the elution pattern from this step, and sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE), the open (active in the absence of interface) form of the lipase is found to be present in solution as a dimer, whereas the closed form appears to be a monomer. The latter form of the enzyme may be activated by up to 60-fold when exposed to triolein.

Studies on the interactions of chiral secondary alcohols with rat hydroxysteroid sulfotransferase STa

Hydroxysteroid (alcohol) sulfotransferase STa catalyzes the 3'-phosphoadenosine 5'-phosphosulfate-dependent O-sulfonation of a diverse array of alcohols including neutral hydroxysteroids. Many of the secondary alcohols that interact with this sulfotransferase are the metabolic products of stereoselective oxidation or reduction reactions. The role that the stereochemistry of secondary alcohol substrates plays in the catalytic efficiency of STa was investigated with a series of chiral benzylic alcohols and the enantiomeric 3-hydroxyl-containing steroids, androsterone and epiandrosterone. In the case of (R)-(+)- and (S)-(-)-enantiomers of 2-methyl-1-phenyl-1-propanol and 1-phenyl-1-butanol, the effect of stereochemistry on the catalytic efficiency of STa was small (less than 2-fold in favor of (R)-(+)-enantiomers). However, as the number of carbons in the alpha-alkyl chain increased, the stereoselectivity for the sulfation of enantiomers increased as well. The (R)-(+)-enantiomers of 1-phenyl-1-pentanol, 1-phenyl-1-hexanol, and 1-phenyl-1-heptanol were preferred as substrates over the (S)-(-)-enantiomers with a 3-fold difference in catalytic efficiency. STa showed absolute stereospecificity in the sulfation of the enantiomers of 1-phenyl-1-cyclohexylmethanol; (R)-(+)-1-phenyl-1-cyclohexylmethanol was a substrate for STa, while the (S)-(-)-enantiomer was a competitive inhibitor of the enzyme. Although a lower degree of stereoselectivity was observed with the 3-hydroxyl-containing steroids, androsterone and epiandrosterone, results with these substrates were also consistent with the conclusion that the stereochemistry of secondary alcohols is an important factor in the catalytic efficiency of STa.

Binding of 2-hydroxy-5-nitrobenzyl alcohol to rat alpha class glutathione S-transferases; evidence for binding at tryptophan 21

2-Hydroxy-5-nitrobenzyl alcohol (HNB) was prepared from dimethyl(2-hydroxyl-5-nitrobenzyl)sulfonium bromide (HNBB). HNB binds to glutathione S-transferases (GSTs) 1-2 and 2-2 with moderate affinity at a site separate from 1-anilino-8-naphthalenesulfonate (ANS). Intrinsic fluorescence due to Trp-21 is strongly quenched by HNB binding but there is no effect on catalytic activity. There appear to be two HNB binding sites per dimer in each GST isoenzyme. We suggest that HNB binds directly at Trp-21 of each subunit and that previously reported quenching of intrinsic fluorescence in these proteins upon ligand binding may be due to indirect structural effects rather than direct binding at this residue.

Aspirin prodrugs: synthesis and hydrolysis of 2-benzyloxy-2-methyl-4H-1,3-benzodioxin-4-ones

Aspirin is widely used for its analgesic, antiinflammatory and antipyretic properties. Among its disadvantages are the relatively narrow therapeutic margin, its irritancy towards the gastric mucosa, and occasionally patient hypersensitivity towards aspirin. As part of our effort to develop prodrugs without these liabilities eleven new title compounds have been isolated and characterized. These 'superaspirin' candidates were subjected to non-enzymatic hydrolysis for a first rapid screening in vitro. Only 2-(2,6-dimethoxybenzyloxy)-2-methyl-4H-1,3-benzodioxin-4-one (4c) was observed to act as an exclusive aspirin prodrug, while 2-(2-methoxybenzyloxy)-2-methyl-4H-1,3-benzodioxin-4-one (4b) and 2-(2-ethoxybenzyloxy)-2-methyl-4H-1,3- benzodioxin-4-one (4d) were shown to release both aspirin 6 and salicylic acid 7. Subsequently, these three candidates were further characterized by investigation of the pH profile of their hydrolysis rates.

Synthesis, properties and prodrug potential of 2-methyl-2-oxy- and 2-methyl-2-thio-4H-1,3-benzodioxin-4-ones

The fifty-four known title compounds are fully documented and their chemical and biological properties discussed in detail. Special attention is devoted to their potential as aspirin and salicylic acid prodrugs, respectively.

Antimalarials. 12. Preparation of carbon isosteres of selected 4-pyridinemethanols as suppressive antimalarials

Four carbon isosteres related to the highly active 4-pyridylcarbinolamines were prepared and evaluated for suppressive antimalarial activity against Plasmodium berghei in mice. Three of the four examples possessed significant activity but were approximately one dose level less active than the corresponding pyridines.

Photolabile multi-detachable p-alkoxybenzyl alcohol resin supports for peptide fragment or semi-synthesis

Two photolabile multi-detachable alkoxybenzyl alcohol resins, 2-[4-(oxymethyl)phenoxy]propionyl-resin 4 and 4-[4-(oxymethyl)phenoxymethyl]-3-nitrobenzamidomethyl-resin 5 have been synthesized. Bpoc-peptide attached to resin 4 or 5 when treated with 50% trifluoroacetic acid provided the free, unprotected peptide, but on photolysis gave Bpoc-peptide p-hydroxybenzyl ester. Removal of the p-hydroxybenzyl ester in aqueous base or by oxidative work up gave a protected Bpoc-peptide suitable for fragment synthesis at its C-terminus. However, methylation of the ester to Bpoc-peptide p-methoxybenzyl ester followed by removal of the Bpoc-group gave a protected peptide p-methoxybenzyl ester suitable for fragment coupling at its N-terminus. The efficacies of these resins were evaluated in the syntheses of a model tetrapeptide and an octapeptide by using N alpha-Bpoc-, Fmoc- and Nps-amino acids. The use of 2-thiopyridine with pyridinium hydrochloride as a new and efficient thiolytic reagent for the deprotection of the Nps-group was studied.

New bronchodilators. Synthesis and bronchodilating activity of some 3-(alkoxymethyl)-alpha-(N-substituted aminomethyl)-4-hydroxybenzyl alcohols

A series of 3-(alkoxymethyl)-alpha-(N-substituted aminomethyl)-4-hydroxybenzyl alcohols was synthesized as potential bronchodilators. The ability to prevent effects against histamine-induced bronchoconstriction in guinea pigs was studied to determine their bronchodilating activity. Introduction of a methoxymethyl group in place of the m-hydroxyl group of beta-adrenergic catecholamines afforded compounds especially effective in delaying histamine-induced bronchoconstriction in guinea pigs. Appropriate N-substitution also enhanced the potency of these catecholamine analogues. 4-Hydroxy-3-(methoxymethyl)-alpha-[N-[4-(methoxymethyl)-alpha-methylphenyl]aminoethyl]benzyl alcohol hemifumarate (3r) was the most potent compound in this series.