Laboratory studies of disinfectants against Legionella pneumophila

Legionella pneumophila suspended in tap water was exposed to biocides recommended for inhibiting biological growth in cooling towers and evaporative condensers of air-conditioning systems. Chlorine, 2,2-dibromo-3-nitrilopropionamide, and a compound containing didecyldimethylammonium chloride and isopropanol were effective in destroying concentratiois of 10(5) to 10(6) viable cells per ml. Formulations consisting of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one, disodium ethylene bis(thiocarbamate) and sodium dimethyl dithiocarbamate, and a phenolic with pentachlorophenate and sodium salts of other chlorophenols were less effective.     

Endophytic bacteria from Ilex paraguariensis shoot cultures: localization, characterization, and response to isothiazolone biocides

Nodal segment explants of Ilex paraguariensis, collected from greenhouse-grown plants, were found to contain endophytic bacteria. After culturing in bioreactors, 16 rRNA gene analyses and analytical profile index biochemical tests were used to identify these bacteria as Stenotrophomonas malthophilia. The presence of bacterial cells in the intercellular spaces of stem cortical parenchyma was detected in histological sections by scanning electron microscopy. A range of commercial isothiazolone biocides were tested for their ability to repress the growth of Gram-negative bacteria grown in liquid media during the micropropagation phase. The addition of 0.75 ml?l^?1 Delcide^? TG (5-chloro-2-methyl-4-isothiazolin-3-one + 2-methyl-4-isothiazolin-3-one, 1.05% and 0.45%, respectively) to the culture media resulted in 100% visibly clean cultures, with no suppression of shoot growth.     

Assessment and management of human health risk from biocides

The assessment and management of human health risk from biocides is an iterative and multidisciplinary scientific process that seeks to define the inherent hazards of the material and integrate this information with the details of potential human exposure. This paper attempts to outline the critical elements and relationships in this process while presenting the risk assessment process for Kathon microbicides (blend of isothiazolones, 3:1 ratio of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one: MCI/MC) as an illustrative example.     

Human Health Risk Evaluation of ACQ-Treated Wood

Alkaline copper quaternary (ACQ) Type D is one of several compounds currently being used as a chemical preservative to treat wood for prevention of rot and decay. As wood weathers naturally, human exposure to ACQ might occur through dermal contact or incidental ingestion of residues from the wood surface. To understand any potential for health risks from the use of ACQ-treated wood, a health-based evaluation was undertaken on the primary components of ACQ, which are copper, didecyl dimethyl ammonium carbonate, 2-methyl-4-isothiazolin-3-one, and 5-chloro-2-methyl-4-isothiazolin-3-one. For these components, there are no formalized toxicity values in USEPA's Integrated Risk Information System, although extensive toxicity data are available in the scientific literature. Therefore, health-based toxicity benchmarks were derived from a review of existing toxicity data. The exposure assessment was based on methods developed by the Consumer Product Safety Commission in their evaluation of the potential for children's exposure to arsenic from wood treated with chromated copper arsenate. This approach entailed wipe testing the surface of treated wood to determine the amount of chemical that might be removed from the wood, and estimating the amount of chemical that a child might contact via the dermal route or incidental ingestion through hand-to-mouth activities. All calculated exposure estimates were well below toxicity benchmarks.     

GSH depletion, protein S-glutathionylation and mitochondrial transmembrane potential hyperpolarization are early events in initiation of cell death induced by a mixture of isothiazolinones in HL60 cells

We recently described that brief exposure of HL60 cells to a mixture of 5-chloro-2-methyl-4-isothiazolin-3-one (CMI) and 2-methyl-4-isothiazolin-3-one (MI) induces apoptosis at low concentrations (0.001-0.01%) and necrosis at higher concentrations (0.05-0.1%). In this study, we show that glutathione (GSH) depletion, reactive oxygen species generation, hyperpolarization of mitochondrial transmembrane potential (DeltaPsim) and formation of protein-GSH mixed disulphides (S-glutathionylation) are early molecular events that precede the induction of cell death by CMI/MI. When the cells exhibit common signs of apoptosis, they show activation of caspase-9, reduction of DeltaPsim and, more importantly, decreased protein S-glutathionylation. In contrast, necrosis is associated with severe mitochondrial damage and maximal protein S-glutathionylation. CMI/MI-induced cytotoxicity is also accompanied by decreased activity of GSH-related enzymes. Pre-incubation with L-buthionine-(S,R)-sulfoximine (BSO) clearly switches the mode of cell death from apoptosis to necrosis at 0.01% CMI/MI. Collectively, these results demonstrate that CMI/MI alters the redox status of HL60 cells, and the extent and kinetics of GSH depletion and S-glutathionylation appear to determine whether cells undergo apoptosis or necrosis. We hypothesize that S-glutathionylation of certain thiol groups accompanied by GSH depletion plays a critical role in the molecular mechanism of CMI/MI cytotoxicity.     

Evaluation of some formaldehyde-release compounds and other biocides in the mouse micronucleus test

A number of biocidal chemicals were tested for clastogenic activity in the micronucleus test using C57Bl/6J mice. The materials tested were: 5-chloro-2-methyl-4-isothiazolin-3-one (I), N-methyl-isothiazolone hydrochloride (II), Glokill 77 and Parmetol A23. Two of the biocides (Glokill and Parmetol) depend on the release of formaldehyde for their activity while the other two compounds are the active chemicals in the biocide Kathon. Hexamethylphosphoramide (HMPA) was tested as the positive control for the series and N,N-dinitrosopentamethylenetetramine (DNPT) as the negative control. HMPA produced significant dose-related increases in the incidence of micronuclei whereas DNPT, I, II, Glokill and Parmetol A23 were without effect.     

Iron dependent degradation of an isothiazolone biocide (5-chloro-2-methyl-4-isothiazolin-3-one)

An isothiazolone biocide, 5-chloro-2-methyl-4-isothiazolin-3-one (CMI), was degraded in the presence of iron. According to the Fe-dependent degradation of CMI, stoichiometric production of chloride was observed. Copper and stainless steel did not enhance the physico-chemical degradation of CMI, whilst phosphate inhibited the Fe-dependent degradation. Neither aerobic nor anaerobic conditions influenced the Fe-dependent CMI degradation. Furthermore, FeO(OH)-powder and Fe(3)O(4)-powder did not lead to the physico-chemical degradation of CMI. Rapid disappearance of CMI was observed in an operating cooling water plant. CMI added to the cooling tower declined from 1.4 mg l(-1) to < 0.1 mg l(-1) in 2 d. This finding is important in optimising the use of CMI and combating resistance if encountered.     

Synthesis, antioxidant and toxicological study of novel pyrimido quinoline derivatives from 4-hydroxy-3-acyl quinolin-2-one

A series of novel pyrimido and other fused quinoline derivatives like 4-methyl pyrimido [5,4-c]quinoline-2,5(1H,6H)-dione (4a), 4-methyl-2-thioxo-1,2-dihydropyrimido [5,4-c]quinoline-5(6H)-one (4b), 2-amino-4-methyl-1,2-dihydropyrimido [5,4-c]quinolin-5(6H)-one (4c), 3-methylisoxazolo [4,5-c]quinolin-4(5H)-one (4d), 3-methyl-1H-pyrazolo [4,3-c]quinoline-4(5H)-one (5e), 5-methyl-1H-[1,2,4] triazepino [6,5-c]quinoline-2,6(3H,7H)-dione (5f), 5-methyl-2-thioxo-2,3-dihydro-1H-[1,2,4]triazepino [6,5-c]quinolin-6(7H)-one (5 g) were synthesized regioselectively from 4-hydroxy-3-acyl quinolin-2-one 3. They were screened for their in vitro antioxidant activities against radical scavenging capacity using DPPH(), Trolox equivalent antioxidant capacity (TEAC), total antioxidant activity by FRAP, superoxide radical (O(2)(°-)) scavenging activity, metal chelating activity and nitric oxide scavenging activity. Among the compounds screened, 4c and 5 g exhibited significant antioxidant activities.     

New imidazolidinic bioisosters: potential candidates for antischistosomal drugs

The emergence of strains of Schistosoma resistant to praziquantel has drawn attention to the search for new schistosomacide drugs. Imidazolidinic derivatives have performed outstandingly against adult S. mansoni worms when evaluated in vitro. The molecular modification of imidazolidine by way of bioisosteric replacement gives rise to variations in its biological response. This study verifies the potential of substituent groups in the derivatives (Z)3-benzyl-5-(2-fluoro-benzylidene)-imidazolidine-2,4-dione NE4, 3-benzyl-5-(4-chloro-arylazo)-4-thioxo-imidazolidin -2-ona PT5, 3-benzyl-5-(3-fluoro-benzylidene)-1-methyl-2-thioxo-imidazolidin-4-one JT53; 3-benzyl-1-methyl-5-(4-methyl-benzylidene)-2-thioxo-imidazolidin-4-one JT63; 3-benzyl-1-methyl-5-(4-methoxi-benzylidene)-2-thioxo -imidazolidin-4-one JT68; 3-(4-chloro-benzyl)-1-methyl-5-(4-methoxi-benzylidene)-2-thioxo-imidazolidin-4-one JT69; 3-(4-phenyl-benzyl)-1-methyl-5-(4-methoxi-benzylidene)-2-thioxo-imidazolidin-4-one JT72 by determining the viability in vitro of adult S. mansoni worms in the presence of these derivatives. The susceptibility of the worms obtained from mice and kept in culture in the presence of different concentrations was determined by way of schistosomacide kinetic, observed every 24 h over a period of eight days. The results show that the worms were more sensitive to the PT5 derivative at a concentration of 58 microM which killed 100% of the worms after 24 h of contact, also giving rise to alterations in the tegument surface of the worms with the formation of bubbles and peeling. These observations suggest a strong electronic contribution of the arylazo grouping in the biological response.     

Reactions of D-xylose and D-glucose in alkaline,aqueous solutions

Treatment of D-xylose and D-glucose with 0.63M sodium hydroxide at 96° in an atmosphere of nitrogen yielded, in addition to acidic, aliphatic degradation-products, the following cyclic enols and phenolic compounds: 2-hydroxy-3-methyl-2-cyclopenten-1-one (1), 2-hydroxy-3,4-dimethyl-2-cyclopenten-1-one (2), pyrocatechol (3), 3-methyl-1,2-benzenediol (4), 4-methyl-1,2-benzenediol (5), 3,4-di-methyl-1,2-benzenediol (6), 2-methyl-1,4-benzenediol (7), 2,5-dihydroxyacetophe-none (8), 3-hydroxy-5-methylacetophenone (9), 3,4-dihydroxyacetophenone (10), 3,4-hydroxybenzaldehyde (11), 2,3,4-trihydroxy-5-methylacetophenone (12), and 2,3-dihydroxy-6-methylacetophenone (13).     

Homoisoflavonoids from Ophiopogon japonicus Ker-Gawler

From the ethyl acetate extract of the tuberous roots of Ophiopogon japonicus (Liliaceae) eight known and five new homoisoflavonoidal compounds were isolated. The new compounds are 5,7-dihydroxy-8-methoxy-6-methyl-3-(2'-hydroxy-4'-methoxybenzyl)chroman-4-one (1), 7-hydroxy-5,8-dimethoxy-6-methyl-3-(2'-hydroxy-4'-methoxybenzyl)chroman-4-one (2), 5,7-dihydroxy-6,8-dimethyl-3-(4'-hydroxy-3'-methoxybenzyl)chroman-4-one (3), 2,5,7-trihydroxy-6,8-dimethyl-3-(3',4'-methylenedioxybenzyl)chroman-4-one (4) and 2,5,7-trihydroxy-6,8-dimethyl-3-(4'-methoxybenzyl)chroman-4-one (5). Their structures have been elucidated by mass and NMR spectroscopy. Compounds 4 and 5 are the first isolated homoisoflavonoids with a hemiacetal function at position 2.     

The chemistry of 9 alpha-hydroxysteroids. 1. Preparation of 9 alpha,17 beta-dihydroxy-17 alpha-ethynylandrost-4-en-3-one

9 alpha-Hydroxyandrost-4-ene-3,17-dione 1, when allowed to react with dipotassium acetylide in tetrahydrofuran, resulted, after chromatographic separation, in 4-methyl-19-norandrosta-4,9-diene-1,17-dione 2, 4 xi-methyl-19-norandrosta-5(10),9(11)-diene-1,17-dione 3, 4-methyl-17 alpha-ethynyl-17 beta-hydroxy-19-norandrosta-4,9-dien-1-one 4, 4 xi-methyl-17 alpha-ethynyl-17 beta-hydroxy-19-norandrosta-5(10),9(11)-dien- 1-one 5, and 17 alpha-ethynyl-17 beta-hydroxy-9,10-secoandrost-4-ene-3,9-dione 6. Selective protection of delta 4-3-ketone of 9 alpha-hydroxyandrost-4-ene-3,17-dione 1 as its dienol methyl ether 7, and subsequent reaction with lithium acetylide-ethylenediamine followed by acidic hydrolysis, afforded 9 alpha,17 beta-dihydroxy-17 alpha- ethynylandrost-4-en-3-one 8.     

Steroidal constituents of Solanum xanthocarpum

From the extract of the fruits of Solanum xanthocarpum (Solanaceae), five new steroidal compounds were isolated and characterized: 4α-methyl-24ξ-ethyl-5α-cholest-7-en-3β,22ξ-diol (1), 3β,22ξ-dihydroxy-4α-methyl-24ξ-ethyl-5α-cholest-7-en-6-one (2), 3β-benzoxy-14β,22ξ-dihydroxy-4α-methyl-24ξ-ethyl-5α-cholest-7-en-6-one (3), 3β-benzoxy-14α,22ξ-dihydroxy-4α-methyl-24ξ-ethyl-5α-cholest-7-en-6-one (4) and 3β-(p-hydroxy)-benzoxy-22ξ-hydroxy-4α-methyl-24ξ-ethyl-5α-cholest-7-en-6-one (5).     

Differential biocide susceptibility of the multiple genotypes of <Emphasis Type="Italic">Mycobacterium immunogenum</Emphasis>

The non-tuberculous mycobacterium Mycobacterium immunogenum colonizes industrial metalworking fluids (MWFs) presumably due to its relative resistance to the currently practiced biocides and has been implicated in occupational respiratory hazards, particularly hypersensitivity pneumonitis. With an aim to understand its inherent biocide susceptibility profile and survival potential in MWF, five different genotypes of this organism, including a reference genotype (700506) and four novel test genotypes (MJY-3, MJY-4, MJY-10 and MJY-12) isolated in our recent study from diverse MWF operations were evaluated. For this, two commercial biocide formulations, Grotan (Hexahydro-1,3,5-tris(2-hydroxyethyl)-s-triazine) and Kathon (5-chloro-2-methyl-4-isothiazolin-3-one) currently practiced for the control of microorganisms, including mycobacteria, in MWF operations were tested. Effect of the fluid matrix on the biocide susceptibility was investigated for the synthetic (S) and semi-synthetic (SS) MWF matrices. In general, the minimum inhibitory concentration values were higher for the HCHO-releasing biocide Grotan than the isothiazolone biocide Kathon. All genotypes (except the reference genotype) showed lower susceptibility in SS as compared to S fluid matrix for Grotan. However, in case of Kathon, a greater susceptibility was observed in SS fluid for majority of the test genotypes (MJY-3, 4 and 10). The test genotypes were more resistant than the reference genotype to either biocide in both fluid types. Furthermore, the individual genotypes showed differential biocidal susceptibility, with MJY-10 being the most resistant. These observations emphasize the importance of using the resistant genotypes of M. immunogenum as the test strains for formulation or development and evaluation of existing and novel biocides, for industrial applications.     

Reaction of thiol nucleophiles with 1,2-epoxy- and 4,5-epoxy-estrene-3-one-17 beta-ols

Four ring A steroidal epoxyenones as probable intermediate in the formation of catechol estrogens were synthesized. The isomeric 1 alpha,2 alpha-epoxy-17 beta-hydroxyestr-4-en-3-one (9) and 1 beta,2 beta-epoxy-17 beta-hydroxyestr-4-en-3-one (8) were synthesized from 17 beta-hydroxy-5 alpha-estra-3-one. The isomeric 4 alpha,5 alpha-epoxy-17 beta-hydroxyestr-1-en-3-one (11) and 4 beta,5 beta-epoxy-17 beta-hydroxyestr-1-en-3-one (10) were prepared from 19-nortestosterone. The reaction of 9 and 10 with sodium/ethanethiol resulted in the formation of three types of reactions leading to multiple products: 1,4-addition, opening of epoxide, and epoxide opening followed by dehydration. Reaction of 8 with ethanethiol gave only one compound identified as 2-ethanethio-1,4-estradien-17 beta-ol-3-one, while reaction of 9 with ethanethiol gave an unusual product identified as 4-estren-1 alpha,17 beta-diol-3-one. Unlike reaction of ethanethiol with 9 and 10, reaction with N-acetylecysteine or glutathione results in epoxide opening followed by dehydration leading to the formation of estradiol-4-thioethers.     

Synthesis and immunomodulatory properties of selected oxazolone derivatives

Eleven oxazolone derivatives were synthesized and characterized by (1)H NMR, EI, IR and UV spectroscopic and CHN analysis. Three compounds, 4-[(E)-(4-nitrophenyl)methylidene]-2-phenyl-1,3-oxazol-5(4H)-one (11), 4-[(E)-(4-methoxyphenyl)methylidene]-2-methyl-1,3-oxazol-5-one (12) and 4-[(E)-(4-nitrophenyl)methylidene]-2-methyl-1,3-oxazol-5(4H)-one (13) were screened for phagocyte chemiluminescence, neutrophil chemotaxis, T-cell proliferation, cytokine production from mononuclear cells and cytotoxicity. 4-[(E)-(4-Nitrophenyl)methylidene]-2-methyl-1,3-oxazol-5(4H)-one (13) was found to be the most potent immunomodulator in the series.     

Synthesis and inhibitory activity of new benzimidazole derivatives against Burkitt's lymphoma promotion

As a continuation to our previous work concerning antitumor benzimidazoles, we have synthesized series of new derivatives of 2-(1-benzyl-2-methyl-1H-benzimidazol-5-ylimino)-3-(substituted)-thiazolidin-4-one (6a-e), 3-(2-methyl-1H-benzimidazol-5-yl)-2-substituted-thiazolidin-4-one (9a-f) and we have studied their inhibitory activity against the Epstein-Barr virus-early antigen (EBV-EA) activation introduced by 12-O-tetradecanoylphorbol-13-acetate (TPA). Compound 6d was found to be significantly active and compounds 5a and 6e were also active.     

Syntheses and biological activities of pyranyl-substituted cinnamates

Twenty-two kinds of pyranyl-substituted cinnamates were synthesized by the reaction of 4-hydroxy-6-(2-phenylethyl)-2H-pyran-2-one or 4-hydroxy-6-methyl-2H-pyran-2-one (HMP) with a variety of substituted cinnamic acids, and their antifungal and plant growth inhibitory activities were investigated. Among the compounds prepared, 6-methyl-2-oxo-2H-pyran-4-yl 3-(4-isopropylphenyl)propenoate (H5) showed the strongest antifungal activity against Rhizoctonia solani and Sclerotium dellfinii, and 6-methyl-2-oxo-2H-pyran-4-yl 3-(2-methylphenyl)propenoate (H2) had the highest plant growth inhibitory activity toward Brassica rapa.     

Phosphodiesterase inhibitors. Part 4: Design, synthesis and structure-activity relationships of dual PDE3/4-inhibitory fused bicyclic heteroaromatic-4,4-dimethylpyrazolones

(-)-6-(7-Methoxy-2-trifluoromethylpyrazolo[1,5-a]pyridin-4-yl)-5-methyl-4,5-dihydro-3-(2H)-pyridazinone (KCA-1490) is a dual PDE3/4 inhibitor that exhibits potent combined bronchodilatory and anti-inflammatory activity. Here we show that a 4,4-dimethylpyrazolone subunit serves as an effective surrogate for the 5-methyl-4,5-dihydropyridazin-3(2H)-one ring of KCA-1490 whilst lacking a stereogenic centre. The 2- and 7-substituents in the pyrazolo[1,5-a]pyridine subunit markedly influence the PDE-inhibitory profile and can be adjusted to afford either potent PDE4-selective inhibitors or dual PDE3/4 inhibitors. A survey of bicyclic heteroaromatic replacements for the pyrazolo[1,5-a]pyridine allowed further refinement of the inhibitory profile and identified 3-(8-methoxy-2-(trifluoromethyl)imidazo[1,2-a]pyridin-5-yl)-4,4-dimethyl-1H-pyrazol-5(4H)-one as an orally active, achiral KCA-1490 analog with well-balanced dual PDE3/4-inhibitory activity.     

Evaluation of the antiviral activity of natural sulfated polyhydroxysteroids and their synthetic derivatives and analogs.

Disodium 3beta,21-dihydroxypregn-5-en-20-one disulfate (2), sodium 3beta,21-dihydroxypregn-5-en-20-one 3-sulfate (3), sodium 3beta,21-dihydroxypregn-5-en-20-one 21-sulfate (4), and disodium 3beta,6alpha-dihydroxy-5alpha-pregnan-20-one disulfate (6) have been synthesized and completely characterized for the first time from readily available materials. Sulfation was performed using triethylamine-sulfur trioxide complex in dimethylformamide as the sulfating agent. Selective sulfation of 3beta,21-dihydroxypregn-5-en-20-one rendered sodium 3beta,21-dihydroxypregn-5-en-20-one 3-sulfate (3) as the major compound. The synthetic sulfated steroids as well as natural disulfated polyhydroxysteroids (7-9) isolated by us from the antarctic ophiuroid Astrotoma agassizii and the synthetic derivatives disodium 2beta,3alpha,21-trihydroxy-(20R)-cholesta-5,24-diene 3-acetate, 2,21-disulfate (7a) and 2beta,3alpha,21-trihydroxy-(20R)-cholesta-5,24-diene (7b) were comparatively evaluated for their inhibitory effect on the replication of one DNA (HSV-2) and two RNA (PV-3, JV) viruses. In general, steroids with sulfate groups at C-21 and C-2 or C-3 were the most effective in their inhibitory action against HSV-2 and also proved to be active against PV-3 and JV.