Production of DON-related trichothecenes byFusarium graminearum Schw from Krasnodarski krai of the USSR

34Fusarium graminearum Schw isolates produced 4-deoxynivalenol to form significant amounts of 4, 7 — dideoxynivalenol and lesser amounts of 4 — deoxynivalenol monoacetates on grain substratesin vitro. This is the first report on the capability a large group of naturally occurring isolates to produce 4,7-dideoxynivalenol. The average levels of 4,7-dideoxynivalenol on rice, corn, barley, and wheat as a substrate were respectively 26.8, 14.0, 12.8, and 10.5% of the level of 4-deoxynivalenol. 4, 7 — dideoxynivalenol was present in all examined naturally contaminated wheat kernel samples at levels of 1.7 to 7.9% of the level of 4-deoxynivalenol. These findings suggest that more attention should be given to the occurrence of 4,7-dideoxynivalenol in cereals.     

Lack of inhibition by l-1-chloro-4-phenyl-3-toluene-p-sulphoamidobutan-2-one (l-1-tosylamido-2-phenylethyl chloromethyl ketone) of the formation of bacterial polypeptide chain initiation complex (Short Communication)

The chymotrypsin inhibitor l-1-chloro-4-phenyl-3-toluene-p-sulphonamidobutan-2-one does not inhibit the function of the initiation factor during the formation of the polypeptide chain initiation complex in vitro. Since the inhibitor has been shown previously to inhibit polypeptide chain elongation by reacting with elongation factor EF-Tu, the inhibitor can be used to investigate the initiation and elongation steps of protein biosynthesis separately.     

Acute toxicity of 12,13-epoxytrichothecenes in one-day-old broiler chicks

Acute toxic effects of several 12,13-epoxytrichothecenes were investigated in 1-day-old broiler chicks by single oral doses. The 7-day median lethal dose values of purified 8-acetylneosolaniol, diacetoxyscirpenol, T-2 toxin, HT-2 toxin, neosolaniol, deacetyl-HT-2 toxin, and T-2 tetraol were 3.22 +/- 0.26, 3.82 +/- 0.40, 4.97 +/- 0.44, 7.22 +/- 0.39, 24.87 +/- 2.64, 30.18 +/- 7.53 (incomplete value), and 33.79 +/- 5.39 mg/kg of body weight, respectively. Deaths occurred during the 8- to 60-h period after dosing with the tested trichothecenes. Within 4 to 10 h after dosing, inappetence, asthenia, diarrhea, and coma generally developed. Sublethal doses of each toxin decreased feed consumption and weight gain proportionally with the amounts of toxins administered. These results demonstrate that the toxic potency of 12,13-epoxytrichothecenes varies depending on the modification of side chains in the molecule.     

Acute toxicity of 12,13-epoxytrichothecenes in one-day-old broiler chicks.

Acute toxic effects of several 12,13-epoxytrichothecenes were investigated in 1-day-old broiler chicks by single oral doses. The 7-day median lethal dose values of purified 8-acetylneosolaniol, diacetoxyscirpenol, T-2 toxin, HT-2 toxin, neosolaniol, deacetyl-HT-2 toxin, and T-2 tetraol were 3.22 +/- 0.26, 3.82 +/- 0.40, 4.97 +/- 0.44, 7.22 +/- 0.39, 24.87 +/- 2.64, 30.18 +/- 7.53 (incomplete value), and 33.79 +/- 5.39 mg/kg of body weight, respectively. Deaths occurred during the 8- to 60-h period after dosing with the tested trichothecenes. Within 4 to 10 h after dosing, inappetence, asthenia, diarrhea, and coma generally developed. Sublethal doses of each toxin decreased feed consumption and weight gain proportionally with the amounts of toxins administered. These results demonstrate that the toxic potency of 12,13-epoxytrichothecenes varies depending on the modification of side chains in the molecule.     

Substituted thiophene-anthranilamides as potent inhibitors of human factor Xa

A series of thiophene-containing non-amidine factor Xa inhibitors is described. Simple methyl-substituted thiophene analogs were relatively weak inhibitors. However, introduction of hydrophilic substituents at C-4 or C-5 of the thiophene afforded inhibitors with low nanomolar potency. Optimization of the thiophene substituent at C-4 afforded subnanomolar inhibitors with improved in vitro anticoagulant activity. Incorporating basic amine substituents on the thiophene increased hydrophilicity and improved anticoagulant activity. The pharmacokinetic profile of one inhibitor was evaluated in dogs, and the X-ray crystal structure of this compound bound to factor Xa provides insight into the observed SAR for binding to factor Xa.     

Protein synthesis by mammalian cells treated with C-3-modified analogs of the 12,13-epoxytrichothecenes T-2 and T-2 tetraol

Modification at the C-3 position of the trichothecenes T-2 and T-2 tetraol affected their ability to inhibit protein synthesis in African green monkey kidney (Vero) and mouse erythroleukemia cells. Replacement of the 3-hydroxyl of T-2 with hydrogen caused a 24-fold decrease in activity, whereas acetylation resulted in a 500-to 1,000-fold decrease. Protection of the 3-hydroxyl with a tetrahydropyranyl moiety gave an analog that was 37-fold more inhibitory to Vero than to mouse erythroleukemia cells; with the other analogs a similar effect on protein synthesis was found for both types of cells. The analogs obtained after alkaline hydrolysis were much less potent than the parent trichothecenes. The 3-tetrahydropyranyl-modified analog was equivalent in potency to T-2 tetraol, while the deoxygenated species was at least threefold less potent. All T-2 analogs caused some degree of polysome "runoff," thereby demonstrating that these species inhibit protein synthesis at the chain initiation stage when added at their 50% infective dose concentrations or lower. From these results, we suggest that the 3-hydroxyl moiety is essential for T-2 to exhibit such high activity on eucaryotic cell protein synthesis and that modification at the C-3 position decreases but does not eliminate this activity.     

Protein synthesis by mammalian cells treated with C-3-modified analogs of the 12,13-epoxytrichothecenes T-2 and T-2 tetraol.

Modification at the C-3 position of the trichothecenes T-2 and T-2 tetraol affected their ability to inhibit protein synthesis in African green monkey kidney (Vero) and mouse erythroleukemia cells. Replacement of the 3-hydroxyl of T-2 with hydrogen caused a 24-fold decrease in activity, whereas acetylation resulted in a 500-to 1,000-fold decrease. Protection of the 3-hydroxyl with a tetrahydropyranyl moiety gave an analog that was 37-fold more inhibitory to Vero than to mouse erythroleukemia cells; with the other analogs a similar effect on protein synthesis was found for both types of cells. The analogs obtained after alkaline hydrolysis were much less potent than the parent trichothecenes. The 3-tetrahydropyranyl-modified analog was equivalent in potency to T-2 tetraol, while the deoxygenated species was at least threefold less potent. All T-2 analogs caused some degree of polysome "runoff," thereby demonstrating that these species inhibit protein synthesis at the chain initiation stage when added at their 50% infective dose concentrations or lower. From these results, we suggest that the 3-hydroxyl moiety is essential for T-2 to exhibit such high activity on eucaryotic cell protein synthesis and that modification at the C-3 position decreases but does not eliminate this activity.     

Inhibition of replicon initiation by 12-O-tetradecanoylphorbol-13-acetate

To investigate the inhibition of DNA replication by tumor promoters, we incubated HeLa cells with 12-O-tetradecanoylphorbol-13-acetate (TPA; 10^?8 to 10^?5 g/ml) and quantified DNA synthesis on alkaline sucrose gradients. TPA was found to selectively inhibit replicon initiation without affecting DNA chain elongation in replicons that had already initiated. No inhibition of DNA synthesis was seen when cells were exposed to the nonpromoting derivative of TPA, 4-α-phorbol 12,13-didecanoate. Superoxide dismutase did not prevent the TPA-induced inhibition of initiation.     

Design, synthesis, and biological evaluation of combretastatin nitrogen-containing derivatives as inhibitors of tubulin assembly and vascular disrupting agents

A series of analogs with nitro or serinamide substituents at the C-2'-, C-5'-, or C-6'-position of the combretastatin A-4 (CA4) B-ring was synthesized and evaluated for cytotoxic effects against heart endothelioma cells, blood flow reduction to tumors in SCID mice, and as inhibitors of tubulin polymerization. The synthesis of these analogs typically featured a Wittig reaction between a suitably functionalized arylaldehyde and an arylphosphonium salt followed by separation of the resultant E- and Z-isomers. Several of these nitrogen-modified CA4 derivatives (both amino and nitro) demonstrate significant inhibition of tubulin assembly as well as cytotoxicity and in vivo blood flow reduction. 2'-Aminostilbenoid 7 and 2'-amino-3'-hydroxystilbenoid 29 proved to be the most active in this series. Both compounds, 7 and 29, have the potential for further pro-drug modification and development as vascular disrupting agents for treatment of solid tumor cancers and certain ophthalmological diseases.     

Inhibitory effects of 2-substituted-1-naphthol derivatives on cyclooxygenase I and II

Naphthol derivatives, 2-(3'-hydroxypropyl)-naphthalen-1-ol (2), 2-(3'-hydroxy-2'-methylpropyl)-naphthalen-1-ol (3) and 2-(3'-hydroxy-2',2'-dimethylpropyl)-naphthalen-1-ol (7) were synthesized and already reported by our group. Therefore in this paper we described further synthesis of their ether derivatives, 3-(1-methoxy-naphthalen-2-yl)-propan-1-ol (4), 3-(1-methoxy-naphthalen-2-yl)-2methyl-propan-1-ol (5), 3-(1-methoxy-naphthalen-2-yl)-2,2-dimethyl-propan-1-ol (8), 2-(3-methoxy-propyl)-naphthalen-1-ol (10) and 2-(3-methoxy-2,2-dimethyl-propyl)-naphthalen-1-ol (13). Compounds 4, 5 and 8 were prepared by methylation of compounds 2, 3 and 7, respectively while compounds 10 and 13 were prepared in good yield from naphthols 2 and 7, respectively. When tested for inhibitory activity, five compounds (2, 3, 7, 10 and 13) showed preferential inhibition of COX-2 over COX-1, while compounds 4, 5 and 8 lacked inhibitory effect on either the COX-1 or COX-2 isozyme. The structure-activity relationships of these naphthols analyzed by docking experiments, indicated that the presence of hydroxyl group at C-1 position on the naphthalene nucleus enhanced the anti-inflammatory activity towards COX-2 via hydrogen bonding to the COX-2 Val 523 side chain. When this hydroxyl group was replaced by methoxy group, there was no inhibition. C-2' Dimethyl substituents on the propyl chain also increased the inhibitory activity. All active compounds have the C-1 hydroxyl group aligned so as to form hydrogen bond with Val 523. The results provide a model for the binding of the naphthol derivatives to COX-2 and facilitate the design of more potent or selective analogs prior to synthesis.     

Effect of substitution on novel tricyclic HIV-1 integrase inhibitors

A series of novel tricyclic inhibitors of HIV-1 integrase enzyme was prepared. The effect of substitution at C-6 of the 9-hydroxy-6,7-dihydropyrrolo[3,4-g]quinolin-8-one compounds was studied in vitro. Inhibitors with small side chains at C-6 were generally well tolerated by the enzyme, and the physicochemical properties of the inhibitors were improved by substitution of a small alkyl group at this position. A second series of analogs bearing a sulfamate at the C-5 position with various C-6 substituents were prepared to explore the interplay between the two groups. The SAR of the two classes are not parallel; modification at C-5 impacts the effect of substitutions at C-6.     

Synthesis and structure-activity relationships of 1,5-diazaanthraquinones as antitumour compounds

1,5-Diazaanthraquinone derivatives were synthesized employing single and double hetero Diels-Alder strategies. Their in vitro antitumour activity was assayed using three cell lines. Some of these compounds, specially those bearing methyl or ethyl groups at the C-3,7 positions or chloro at C-4 and methyl at C-7, showed IC(50) values in the 10(-8)M range for human lung carcinoma and human melanoma, which makes them attractive candidates for further development as anticancer agents.     

Structure-activity relationship study of taxoids for their ability to activate murine macrophages as well as inhibit the growth of macrophage-like cells

A series of new taxoids modified at the C-3', C-3'N, C-10, C-2 and C-7 positions has been designed, synthesized and evaluated for their potency to induce NO and TNF production by peritoneal murine macrophages (Mphi) from LPS-responsive C3H/HeN and LPS-hyporesponsive C3H/HeJ strains and human blood cells, and for their ability to inhibit the growth of Mphi-like cell lines J774.1 and J7.DEF3. The SAR-study has shown that the nature of the substituents at these positions have critical effect on the induction of TNF and NO production by Mphi. Positions C-3' and C-10 are the most flexible and an intriguing effect of the length of the substituents at the C-10 position is observed for taxoids bearing a straight chain alkanoyl moiety. An aromatic group at the C-3'N and C-2 positions is required for the activity, while only hydroxyl or acetyl substituents seem to be tolerated at the C-7 position. The natural stereochemistry in the C-13 isoserine side chain of the taxoids is an absolute requirement for macrophage activation. It has also been clearly shown that there is no correlation between the ability of the taxoids to induce TNF/NO production in C3H/HeN Mphi and the cytotoxicity against Mphi-like cells.     

Design and synthesis of (Z)-1,2-diphenyl-1-(4-methanesulfonamidophenyl)alk-1-enes and (Z)-1-(4-azidophenyl)-1,2-diphenylalk-1-enes: novel inhibitors of cyclooxygenase-2 (COX-2) with anti-inflammatory and analgesic activity

A group of novel (Z)-1,2-diphenyl-1-(4-methanesulfonamidophenyl)alk-1-enes was designed for evaluation as selective cyclooxygenase-2 (COX-2) inhibitors. In vitro COX-1/COX-2 enzyme inhibition studies identified (Z)-1,2-diphenyl-1-(4-methanesulfonamidophenyl)oct-1-ene (8d) as a highly potent (IC50=0.03 microM), and an extremely selective [COX-2 SI (selectivity index)>3,333], COX-2 inhibitor that showed good anti-inflammatory (AI) activity (ID50=2.8 mg/kg). A molecular modeling (docking) study showed that the p-MeSO2NH group present in (Z)-8d inserts deep inside the 2 degrees-pocket of the COX-2 binding site, it undergoes a hydrophobic interaction with Ala516 and Gly519, and one of the O-atoms of the MeSO2 group participates in a weak hydrogen bonding interaction with the NH2 of Arg513 (distance= 3.85 angstroms). Similar in vitro COX-1/COX-2 enzyme inhibition studies showed that the azido compound 1-(4-azidophenyl)-1,2-diphenyloct-1-ene (9c) is also a potent and selective COX-2 inhibitor (COX-2 IC50=0.11 microM: SI>909) that exhibits good AI activity (ID50=5.0 mg/kg). A docking experiment to determine the orientation of (Z)-9c within the COX-2 binding site showed that the linear p-N3 group inserts into the COX-2 2 degrees-pocket, where it undergoes an ion-ion (electrostatic) interaction with Arg513. Structure-activity data acquired indicate that an olefin having either a C-1 p-MeSO2NH-phenyl, or a p-N3-phenyl, substituent, that is, cis to a C-2 unsubstituted phenyl substituent, in conjunction with C-1 unsubstituted phenyl and C-2 alkyl substituents, provides a novel template to design acyclic olefinic COX-2 inhibitors.     

Inhibition of bovine adrenocortical mitochondrial cytochrome P-450(11)beta-mediated reactions by imidazole derivatives and mineralocorticoid analogs

The effects of several imidazole antimycotic agents, an imidazole and several mineralocorticoid analogs on the cytochrome P-450(11)beta-catalyzed 11 beta-hydroxylation of 11-deoxycorticosterone and aldosterone synthesis were examined. Ketoconazole, clotrimazole, miconazole and etomidate were found to be potent inhibitors of the reactions, causing 50% inhibition of the 11 beta-hydroxylase activity at concentrations between 10(-8) and 10(-7) M. The potency of etomidate as to the inhibition of aldosterone- and 18-hydroxycorticosterone-production was found to be almost equal to that in the case of 11 beta-hydroxylation. Spironolactone and other newly synthesized mineralocorticoid analogs were also found to inhibit the cytochrome P-450(11)beta-mediated reactions. The ID50 values of these drugs for inhibition of the 11 beta-hydroxylase activity were almost equal to those in the case of the aldosterone- and 18-hydroxycorticosterone-biosynthetic activities. The results of kinetical studies indicated that one of the mineralocorticoid analogs, Compound 23-0586, acts as a competitive inhibitor for the cytochrome P-450(11)beta-mediated reactions.     

Preparation of theFusarium toxin,nivalenol, by oxidation of the putative biosynthetic precursor, 7-deoxynivalenol

Nivalenol is a toxic trichothecene metabolite which is produced by a number of differentFusarium species. However, the nature of its immediate biosynthetic precursor is not known. Oxidation of 7-deoxynivalenol(3,4, 15-trihydroxy-12,13-epoxytrichothec-9-ene-8-one) to nivalenol occurred with reagents known to react by a free radical pathway, such as hydrogen peroxide-ferrous ion-ascorbic acid or lead tetracetate, but not with electrophilic reagents requiring prior formation of the enol. These results suggest that 7-deoxynivalenol or an acetylated derivative could be the biosynthetic precursor of nivalenol.     

Structure-Activity Relationships of Abscisic Acid Analogs Based on the Induction of Freezing Tolerance in Bromegrass (Bromus inermis Leyss) Cell Cultures

The induction of freezing tolerance in bromegrass (Bromus inermis Leyss) cell culture was used to investigate the activity of absisic acid (ABA) analogs. Analogs were either part of an array of 32 derived from systematic alterations to four regions of the ABA molecule or related, pure optical isomers. Alterations were made to the functional group at C-1 (acid replaced with methyl ester, aldehyde, or alcohol), the configuration at C-2, C-3 (cis double bond replaced with trans double bond), the bond order at C-4, C-5 (trans double bond replaced with a triple bond), and ring saturation (C-2′, C-3′ double bond replaced with a single bond so that the C-2′ methyl and side chain were cis). All deviations in structure from ABA reduced activity. A cis C-2, C-3 double bond was the only substituent absolutely required for activity. Overall, acids and esters were more active than aldehydes and alcohols, cyclohexenones were more active than cyclohexanones, and dienoic and acetylenic analogs were equally active. The activity associated with any one substituent was, however, markedly influenced by the presence of other substituents. cis, trans analogs were more active than their corresponding acetylenic analogs unless the C-1 was an ester. Cyclohexenones were more active than cyclohexanones regardless of oxidation level at C-1. An acetylenic side chain decreased the activity of cyclohexenones but increased the activity of cyclohexanones relative to their cis, trans counterparts. Trends suggested that for activity the configuration at C-1′ has to be the same as in (S)-ABA, in dihydro analogs the C-2′-methyl and the side chain must be cis, small positional changes of the 7′-methyl are tolerable, and the C-1 has to be at the acid oxidation level.     

7-(4H-1,2,4-Triazol-3-yl)benzo[c][2,6]naphthyridines: a novel class of Pim kinase inhibitors with potent cell antiproliferative activity

A novel class of pan-Pim kinase inhibitors was designed by modifying the CK2 inhibitor CX-4945. Introduction of a triazole or secondary amide functionality on the C-7 position and 2'-halogenoanilines on C-5 resulted in potent inhibitors of the Pim-1 and Pim-2 isoforms, with many analogs active at single digit nanomolar concentrations. The molecules inhibited the phosphorylation at Serine 112 of the apoptosis effector BAD, and had potent antiproliferative effects on the AML cell line MV-4-11 (IC(50) <30 nM). This work delivers an excellent lead-optimization platform for Pim targeting anticancer therapies.