Conjugated Styryl Ketones Research Articles

Design, Synthesis and Biological Evaluation of Hybrid Molecules Containing Conjugated Styryl Ketone and α-Bromoacryloyl Moieties

There was a major interest in the last years in the design of anticancer agents containing the 1,5-diaryl-3-oxo- 1,4-pentadienyl system. The modification of this pharmacophore by the introduction of an additional Michael acceptor represents a strategy to obtain novel potential antiproliferative agents. In a continuing study of hybrid compounds containing the α-bromoacryloyl moiety as potential anticancer drugs, we synthesized two novel series of hybrids 3a-i and 4a-i, in which this moiety was linked to the 1,5-diaryl-1,4-pentadien-3-one system. Many of the conjugates prepared (3b, 3c and 3g) demonstrated pronounced antiproliferative activity against five cancer cell lines, being more active than the reference compound Melphalan. Compounds 3e and 4b were also examined for their effects on the cell cycle progression of K562 cells. The detection of a sub-G1 peak upon incubation with these compounds suggested that 3e and 4b also exert their growth inhibiting effects by induction of apoptosis.

Inhibition of H(+)-ATPase-mediated proton pumping in Cryptococcus neoformans by a novel conjugated styryl ketone.

We investigated the in vitro susceptibility of clinical isolates of Cryptococcus neoformans to the novel conjugated styryl ketone NC1175 by broth microdilution. The MIC(90) and the MFC of NC1175 for C. neoformans were 1 and 2 mg/L, respectively. NC1175 at low concentrations (1-4 mg/L) completely inhibited the glucose-induced acidification of the external medium caused by the extrusion of intracellular protons mediated by the plasma membrane located H(+)-ATPase. These data suggest that NC1175 is a fungicidal agent for C. neoformans and its possible cellular target(s) include the H(+)-ATPase.

Proton-pumping-ATPase-targeted antifungal activity of a novel conjugated styryl ketone.

NC1175 (3-[3-(4-chlorophenyl)-2-propenoyl]-4-[2-(4-chlorophenyl)vinyle ne]-1- ethyl-4-piperidinol hydrochloride) is a novel thiol-blocking conjugated styryl ketone that exhibits activity against a wide spectrum of pathogenic fungi. Incubation of NC1175 with various concentrations of cysteine and glutathione eliminated its antifungal activity in a concentration-dependent fashion. Since NC1175 is a lipophilic compound that has the potential to interact with cytoplasmic membrane components, we examined its effect on the membrane-located proton-translocating ATPase (H(+)-ATPase) of yeast (Candida albicans, Candida krusei, Candida guilliermondii, Candida glabrata, and Saccharomyces cerevisiae) and Aspergillus (Aspergillus fumigatus, Aspergillus niger, Aspergillus flavus, and Aspergillus nidulans) species. The glucose-induced acidification of external medium due to H(+)-ATPase-mediated expulsion of intracellular protons by these fungi was measured in the presence of several concentrations of the drug. NC1175 (12.5 to 50 microM) inhibited acidification of external medium by Candida, Saccharomyces, and Aspergillus species in a concentration-dependent manner. Vanadate-inhibited hydrolysis of ATP by membrane fractions of C. albicans was completely inhibited by 50 microM NC1175, suggesting that the target of action of NC1175 in these fungi may include H(+)-ATPase.

In-vitro and in-vivo susceptibility of Aspergillus fumigatus to a novel conjugated styryl ketone

We investigated the in-vitro and in-vivo susceptibility of Aspergillus fumigatus to the novel conjugated styryl ketone NC1175 and the results were compared with those obtained for amphotericin B and itraconazole. All 20 clinical isolates of A. fumigatus examined were susceptible to NC1175 (MIC = 5.54 +/- 2.48 mg/L; range 2.92-11.68 mg/L), and the minimum lethal concentration (MLC) was only twice the MIC, suggesting that NC1175 is fungicidal. The mean MIC values of amphotericin B (1.22 +/- 0.58 mg/L; range 0.5-4 mg/L) and itraconazole (0.37 +/- 0.11 mg/L; range 0.125-0.5 mg/L) were approximately nine- and 22-fold, respectively, lower than that of NC1175. Both amphotericin B-resistant (n = 18) and itraconazole-resistant (n = 28) isolates of A. fumigatus were as susceptible to NC1175 as amphotericin B-, and itraconazole-susceptible isolates. Kill curve experiments revealed that NC1175 at 23.35 mg/L (approximately four times the MIC) killed > or = 99% of conidia within 24 h of exposure to the drug. The in-vivo susceptibility of A. fumigatus to NC1175 was investigated using a murine pulmonary aspergillosis model. Treatment of infected mice with amphotericin B or NC1175 did not result in significant improvement of the mean survival (amphotericin B, 7.05 +/- 0.07 days; NC1175, 6.65 +/- 1.25 days) of the animals compared with that of the placebo group (7.21 +/- 1.20 days). However, semiquantitative organ culture revealed that clearance of A. fumigatus occurred in 16.6%, 50% and 66.6% of the mice treated with placebo, NC1175 and amphotericin B, respectively (P value for the control and the treated groups <0.01). These results suggest that NC1175 has in-vivo and in-vitro activity against A. fumigatus and can be used as a prototypic molecule for further development as an antifungal agent.

In vitro antifungal activity of some Mannich bases of conjugated styryl ketones

Four Mannich bases of some conjugated styryl ketones IIa-IId were examined for antifungal activity. These compounds were designed as thiol-alkylators and had two centers for attack by cellular thiols. The most potent compounds IIa and IIb possessed hydrophobic, electron-attracting substituents in the aryl rings and in general had minimum inhibitory concentration (MIC) values of 0.2-25 microM against a variety of fungi. None of the four compounds inhibited the growth of a number of bacteria (MIC > 100 microM). The minimum fungicidal concentration (MFC) values for IIa and IIb were generally either similar or twofold higher than the MIC figures for fungi. Compound IIa demonstrated rapid, concentration-dependent inhibition of the growth of Candida albicans B311. The toxicity of IIa to normal human cells was much lower than the concentrations of this compound required to inhibit fungal growth. In summary, this study of four prototypic molecules has revealed that this class of compounds may have potential for further development as candidate antifungal agents.

In vitro antifungal activity of some Mannich bases of conjugated styryl ketones

Four Mannich bases of some conjugated styryl ketones IIa-IId were examined for antifungal activity. These compounds were designed as thiol-alkylators and had two centers for attack by cellular thiols. The most potent compounds IIa and IIb possessed hydrophobic, electron-attracting substituents in the aryl rings and in general had minimum inhibitory concentration (MIC) values of 0.2-25 μM against a variety of fungi. None of the four compounds inhibited the growth of a number of bacteria (MIC > 100 μM). The minimum fungicidal concentration (MFC) values for IIa and IIb were generally either similar or twofold higher than the MIC figures for fungi. Compound IIa demonstrated rapid, concentration-dependent inhibition of the growth of Candida albicans B311. The toxicity of IIa to normal human cells was much lower than the concentrations of this compound required to inhibit fungal growth. In summary, this study of four prototypic molecules has revealed that this class of compounds may have potential for further development as candidate antifungal agents.Key words: antifungal, styryl ketones, Candida albicans, Aspergillus fumigatus, susceptibility test.

Anticancer and Cytotoxic Properties of Mannich Bases

This review outlines the chemistry and anticancer and cytotoxic properties of certain Mannich bases. It is divided into four parts. The first section summarizes briefly various investigations undertaken by other researchers of the chemical and pharmacological properties of a number of Mannich bases against neoplasms. The remaining portions of this review are summaries of work undertaken in this laboratory. The second part presents the following aspects of the anticancer properties of various Mannich bases namely differences in antileukemic activity between certain conjugated styryl ketones and the related Mannich bases, intramolecular cyclization of various acyclic Mannich bases and the effect on anticancer activity of such a process, prodrug approaches with a view to obtaining preferential toxicity to cancerous rather than normal cells and finally the effect on antineoplastic properties of introducing a second basic centre into these compounds. The third section summarizes the promising in vitro activities of different acyclic Mannich bases against the WiDr human colon cancer cells and the preparation of a group of Mannich bases which are effective against certain drug resistant malignant cells. The evidence for and evaluations of a theory proposed by one of the authors called sequential cytotoxicity is presented followed by a description of the very high cytotoxicity of some 4-piperidones; a group of compounds which may be regarded as cyclic Mannich bases. Finally, some biochemical properties of certain of these compounds are outlined especially with reference to their causing inhibition of respiration in mitochondria, particularly in those organelles obtained from neoplastic tissue.

Inhibition of yeast-to-mycelium conversion of Candida albicans by conjugated styryl ketones.

Candida albicans is a dimorphic pathogenic yeast capable of producing alternate morphological forms (yeast or mycelium) in response to environmental changes. The dimorphism of C. albicans plays an important role in the pathophysiology of this organism. The intracellular level of glutathione, which helps to maintain the oxidation-reduction potential of the cell, is decreased significantly during the yeast-to-mycelium conversion implicating the possible involvement of thiols in the yeast-to-mycelium transition. To evaluate the possible participation of sulphydryl group(s) containing component(s) in the yeast-to-mycelium transition of C. albicans, we examined the effect of a group of newly synthesized thiol-alkylators on the production of germ tubes from yeast cells. Several conjugated styryl ketones which are thiol-alkylators, and p-chloromercuriphenylsulphonate (a known nonpenetrating thiol-blocker) inhibited the yeast-to-mycelium conversion of C. albicans. The thiol-alkylators at 20 microM failed to inhibit four key enzymes (gamma-glutamyltranspeptidase, glutathione reductase, glutathione S-transferase and glutathione peroxidase) involved in glutathione utilization indicating that the inhibition of yeast-to-mycelium conversion is not mediated by the inhibition of glutathione metabolic enzymes. Moreover, these results suggest that a key thiol-blocker sensitive component(s) containing a critical sulphydryl group(s) is involved in the yeast-to-mycelium transition of C. albicans.

ChemInform Abstract: Deamination and Thiolation of Mannich Bases Derived from Conjugated Styryl Ketones.

AbstractMannich bases such as (I) and bis‐Mannich bases such as (III) form the pentadienones (II) upon hydrolysis at 37°C/pH 7.4.

Toxicologic studies on a novel antineoplastic bis-Mannich base, derived from a conjugated styryl ketone

A new bis-Mannich base (NC758) derived from a conjugated styryl ketone has demonstrated activities against human and animal tumors, both in vitro and as xenografts in athymic mice. The present study examined the toxicity of this candidate anticancer drug, when administered intraperitoneally by undertaking LD50, acute dose-response and time-response toxicity studies using CD-1 mice following OECD guidelines An LD50 of 46.9 ± 1.4 mg/kg (males) and 65.2 ± 1.5 mg/kg (females) was calculated using the moving averages method. Signs of toxicity included diarrhea, piloerection, and coma. Gross pathologic findings consisted of an acute fibrinous peritonitis in animals surviving 24 hr or more before death. The acute dose-response study revealed anorexia in mice 24 hr after receiving 25 mg/kg NC758 or more, lasting up to 72 hr in the 50 mg/kg treated group. Neutrophils were significantly elevated in the 25 and 50 mg/kg groups in conjunction with the observed acute peritonitis. Treatment ( p = 0.0001), sex ( p = 0.0008), and treatment/sex interaction ( p = 0.0001) effects were seen in the myeloid-erythroid ratio (MER) of bone marrow. Pathologic changes included thymic necrosis (in all treated mice) and intestinal villous atrophy (in mice treated with 25 and 50 mg/kg). In time-response studies, pathological changes disappeared after 14 days, except for the MER which remained abnormal in males. It was concluded that NC758 was corrosive; hence future studies should utilize the intravenous route, or be given intraperitoneally as divided doses. Its corrosive action may account for the hematological and myelopoietic changes; however, this compound has the potential for irreversible bone marrow changes in CD-1 male mice when given at levels greater than those used for its antineoplastic activity.

Toxicologic Studies on a Novel Antineoplastic Bis-Mannich Base, Derived from a Conjugated Styryl Ketone

Toxicologic Studies on a Novel Antineoplastic Bis-Mannich Base, Derived from a Conjugated Styryl Ketone. ROUSSEAUX, C. G., TOWNSEND, H. G., PHILLIPS, O. A., AND DIMMOCK, J. R. (1990). Fundam. Appl. Toxicol. 14,318–326. A new bis-Mannich base (NC758) derived from a conjugated styryl ketone has demonstrated activities against human and animal tumors, both in vitro and as xenografts in athymic mice. The present study examined the toxicity of this candidate anticancer drug, when administered intraperitoneally by undertaking LD50, acute dose-response and time-response toxicity studies using CD-1 mice following OECD guidelines. An LD50 of 46.9 ± 1.4 mg/kg (males) and 65.2 ± 1.5 mg/kg (females) was calculated using the moving averages method. Signs of toxicity included diarrhea, piloerection, and coma. Gross pathologic findings consisted of an acute fibrinous peritonitis in animals surviving 24 hr or more before death. The acute dose-response study revealed anorexia in mice 24 hr after receiving 25 mg/kg NC758 or more, lasting up to 72 hr in the 50 mg/kg treated group. Neutrophils were significantly elevated in the 25 and 50 mg/kg groups in conjunction with the observed acute peritonitis. Treatment (p = 0.0001), sex (p = 0.0008), and treatment/sex interaction (p = 0.0001) effects were seen in the myeloid-erythroid ratio (MER) of bone marrow. Pathologic changes included thymic necrosis (in all treated mice) and intestinal villous atrophy (in mice treated with 25 and 50 mg/kg). In time-response studies, pathological changes disappeared after 14 days, except for the MER which remained abnormal in males. It was concluded that NC758 was corrosive; hence future studies should utilize the intravenous route, or be given intraperitoneally as divided doses. Its corrosive action may account for the hematological and myelopoietic changes; however, this compound has the potential for irreversible bone marrow changes in CD-1 male mice when given at levels greater than those used for its antineoplastic activity.

Evaluation of some Mannich bases of conjugated styryl ketones and related compounds versus the WiDr colon cancer in vitro

The series of Mannich bases and one group of related α-aminoketones which had either 1 or 2 sites for thiol alkylation were evaluated against the WiDr tumour in vitro. Maximum activity was found in the bis alkylating agents (12–64 times the activity of the reference compound, 5-fluorouracil) and one of these bis Mannich bases had confirmed activity against murine P388 lymphocytic leukemia. No correlations were found with either the rate of alkylation with glutathione or the apparent partition coefficients of selected compounds with activity against the WiDr tumour in vitro.

Effect of 4-dimethylaminomethyl-1-(3-hydroxyphenyl)-1-nonen-3-one Hydrochloride and Related Compounds on Respiration in Rat Liver Mitochondria

4 — Dimethylaminomethyl-1 — (3 — hydroxyphenyl)-1- nonen 3-one hydrochloride (II) was shown to stimulate respiration in rat liver mitochondria at levels of 2.5 μmoles or less; but at levels higher than 5.0 μmoles, respiration was inhibited when succinate and 3-hydroxybutyrate were the substrates. Compound II caused inhibition of respiration in the presence of glutamate over the dose range studied. The stimulating effect of II was attributed to its functioning as an uncoupling agent. Its inhibiting properties were considered to be due to its behaving like antimycin A in blocking transport of electrons between cytochromes b and c1. The effect of II on respiration in mitochondria varied with the pH of the medium. A conjugated styryl ketone, which contained a nuclear hydroxy function and was structurally related to II, also stimulated respiration at low doses while inhibiting respiration at higher concentrations. Etherification of the hydroxy group led to compounds in which only stimulation of respiration was noted.

The reaction of some nuclear substituted acyclic conjugated styryl ketones and related Mannich bases with ethanethiol

The second order rate constants for the reaction of ethanethiol with a number of conjugated nuclear-substituted styryl ketones and related Mannich bases in 50% aqueous acetonitrile was undertaken. Variation of the alkyl group adjacent to the carbonyl function was accompanied by altered avidity to ethanethiol which was explained as being due in part to the varying inductive effects of the alkyl groups which would, in turn, affect the stability of the reaction intermediates. The greatest disparity in reactivity between groups of compounds was between the ketones and analogous Mannich bases which was in accord with the marked difference in bioactivities between these two groups of compounds.

Syntheses and evaluation of ketals, hemithioketals, and dithioketals of conjugated styryl ketones principally for antineoplastic activity

Ketals, hemithioketals, and dithioketals of nuclear-substituted styryl ketones were prepared as latentiated forms of the ketones. This undertaking was based on the premise that there is increased acidity in tumors compared to normal tissue, and thus preferential regeneration of the ketone in neoplastic tissue may occur. Attempts to form 1,3-dioxolans of Mannich bases were unsuccessful. The prepared compounds did not possess significant anticancer properties, but analgesic, anti-inflammatory, antihistaminic, and antimicrobial activities were found in the prepared Mannich bases.

Evaluation of 1-(3,4-dichlorophenyl)-4-dimethylaminomethyl-1-nonen-3-one Hydrochloride effect on Nucleic acid and protein syntheses using murine leukemia L-1210 cells

Several Mannich bases derived from conjugated styryl ketones were shown to have potent cytotoxicity toward murine leukemia L-1210 cells and Walker 256 carcinosarcoma cells in culture. The most cytotoxic derivative, (E)-1-(3,4-dichlorophenyl)-4-dimethylaminomethyl-1-nonen-3-one hydrochloride, profoundly inhibited the incorporation of tritiated leucine into protein(s) and tritiated deoxythymidine into DNA at concentrations of 0.79-1.32 μM in L-1210 cells. At higher concentrations, incorporation of tritiated undine into RNA and tritiated deoxyuridine into DNA was inhibited to a lesser degree. This compound failed to inhibit the enzymes thymidylate synthetase or dihydrofolate reductase up to a concentration of 10−4M and was ineffective in retarding the growth of the Walker 256 carcinosarcoma in rats.

Nuclear‐Substituted Styryl Ketone Analogs: Effects on Neoplasms, Microorganisms, and Mitochondrial Respiration of Tumorous and Normal Cells

Analogs of some antineoplastic and cytotoxic Mannich bases derived from conjugated styryl ketones were prepared and evaluated for activity in the P‐388 lymphocytic leukemia screen. Most of the new compounds had lower antineoplastic and murine toxicity than the parent compounds. Antimicrobial evaluation of some oximes and alcohols related to the Mannich bases revealed activity against certain Gram‐positive bacteria and fungi. Primary pharmacological evaluation showed that some compounds containing a dimethylaminomethyl group displayed analgesic and antihistaminic properties. Five of the Mannich bases were evaluated as respiratory inhibitors in mitochondria derived from hepatic tumors, liver tissue from tumor‐bearing animals, and normal rat liver. No statistical difference between the sensitivity of the three tissues to the compounds was obtained.

Effect of Antineoplastic and Cytotoxic Mannich Bases Derived from Conjugated Styryl Ketones on Mitochondrial Respiration in Rat Liver Cells

Five cytotoxic Mannich bases (5-dimethylamino-1-substituted phenyl- 1-penten-3-ones), three having antineoplastic activity, were evaluat,ed for respiratory-inhibiting properties in rat liver mitochondria in the presence of lour substrates: succinate, glutamate, 3-hydroxybutyrate, and palmitylcarnitine. Four compounds (Ib-Ie) showed significant inhibiting properties which, on occasion, were reversed partially by coenzyme Q10. Evaluation of the spectra of the mitochondria1 cytochromes indicated that Ib-Ie blocked the electron transport chain prior to the sequence of cytochromes. Since inhibition occurred when different substrates were used, a common site of action for Ib-Ie is likely; competition of lb-lc with coenzyme Q10 probably occurs. Compounds Ia-Ie inhibited RNA polymerase from Swiss muuse kidney cells but were virtually bereft of activity versus RNA polymerase from L-1210 leukemia cells. Polarography of the Mannich bases and the related styryl ketones showed that antineoplastic activity was associated with higher half-wave potentials.