Antifungal activity of some mono, bis and quaternary Mannich bases derived from acetophenone

The development of resistance to current antifungal therapeutics drives search for new effective agents. Some Mannich bases have antifungal activity, but no information is available regarding the antifungal activity of acetophenone derived Mannich bases. Mono Mannich bases of acetophenone 1-3 were synthesized and converted into their corresponding bis derivatives, 5-7. Representative quaternary derivatives 4 and 8 were also synthesized. Antifungal activities of the compounds were evaluated using some yeasts and dermatophytes in vitro. Mono Mannich base 3 and quaternary compounds 4 and 8 were found to be 2-16 times more potent than the reference compound amphotericin B against dermatophytes: Trichophyton rubrum, Trichophyton mentagrophytes, and Microsporum canis. Compounds 4 and 8 were also found to be 2 times more effective compared with amphotericin B against the yeast Saccharomyces cerevisiae. Quaternization procedure improved the biological activity dramatically, whereas conversion of mono Mannich bases to corresponding bis derivatives generally did not affect antifungal activity. Our results suggest that acetophenone derived mono Mannich base 3 and quaternary derivatives 4 and 8 may serve as leading compounds for further studies to develop new antifungal agents with their highly potent antifungal activity.     

Synthetic acetylenic antifungal agents.

Several monoamino bis(propynyloxy)benzenes were prepared by a Mannich reaction and tested for antifungal activity against Trichophyton schoenleini, T. mentagraphytes, T. tonsurans, Candida albicans, and Epidermophyton flocossum. In addition, the bis(propynyloxy)benzene intermediates were tested and comparisons were made with standing drugs. The intermediates were found to be the most active, although two Mannich bases possessed considerable activity.     

Evaluation of antimicrobial activities of several mannich bases and their derivatives

The aim of this study was to evaluate the antimicrobial activities of several Mannich bases and their derivatives against pathogenic bacteria and fungi. 3-Dimethylamino-1-phenyl-1-propanone hydrochloride (Ig1) as mono-Mannich base, bis(beta-aroylethyl)methylamine hydrochlorides (B1, B5) as bis-Mannich bases, 3-aroyl-4-aryl-1-methyl-4-piperidinol hydrochlorides (C1, C5) as piperidinol derivatives, which are structural isomers of bis-Mannich bases, N,N'-Bis(3-dimethylamino-1-phenylpropylidene)hydra zine dihydrochlorides (D1) as azine derivative of mono-Mannich base Ig1, and some representative quaternary derivatives (Ig4 and C6), which are quaternary derivatives of Ig1 and C1, respectively, have been synthesized. Aryl parts were phenyl in B1 and C1, and 2-thienyl in B5 and C5. Bis-Mannich bases and quaternary Mannich bases were found to be effective antifungal derivatives. Quaternary mono-Mannich base Ig4 has shown twice the amount of higher antifungal potency against the human pathogenic fungus Microsporum canis compared with the reference drug amphotericin-B and it had equal potency against many other fungi species pathogenic in humans and plants. Ig4 was effective against Staphylococcus aureus among the bacteria tested. Preparation of bis-Mannich bases and qua ternization procedure seemed suitable chemical modifications to prepare effective antifungal compounds. Especially quaternary derivatives Ig4, and to some extent C6, seem to be model compounds to develop new antimicrobial agents for further studies.     

Antimicrobial evaluation of some Mannich bases of acetophenones and representative quaternary derivatives

1-Aryl-3-dimethylamino-1-propanone hydrochlorides Ia-f (series I) as mono-Mannich bases bis(beta-aroylethyl)ethylamine hydrochlorides IIa, IIb, IId, IIe (series II) as bis-Mannich bases, 3-aroyl-4-aryl-1-ethyl-4-piperidinol hydrochlorides (structural isomer of bis derivatives IIIa-e, series III), and some of their representative quaternary salts (Ig, IIIf, IIIg) were synthesized. Antimicrobial activities of the compounds were evaluated against some bacteria and fungi. Series I and III showed antimicrobial activity against gram positive bacteria. All series demonstrated activity against fungi, however, they generally did not affect gram negative bacteria at the concentration range tested (2-64 micrograms/ml). Quaternisation procedure improved the bioactivity in compound IIIa for antibacterial activity and in compounds IIIa and IIIb for antifungal activity against Trichophyton rubrum and Mycosporium canis. There was no relationship between Hammett values of the aryl substituents and bioactivities in series III. The mono-Mannich bases of series I had better antimicrobial activities than bis-Mannich bases of series II. Compounds Ia, If, IIId had equal and compounds If and IIIf had higher antibacterial activities compared to the reference drug, streptomycin (CAS 57-92-1), against various gram positive bacteria. On the other hand, compounds Ia, IIIa, IIIc, IIIe, IIIf, and IIIg had equal and If, IIId, IIIf, IIIg had higher antifungal activity compared to the reference drug, amphotericin-B (CAS 1397-89-3), against various fungi. To conclude, the compounds of series III, having both marked antifungal and antibacterial activities, may serve as candidate compounds for further studies. Especially compound IIIf may serve as a model compound to develop new agents against dermatophytes.     

Biological evaluation and structure-activity relationships of bis-(3-aryl-3-oxo-propyl)-methylamine hydrochlorides and 4-aryl-3-arylcarbonyl-1-methyl-4-piperidinol hydrochlorides as potential cytotoxic agents and their alkylating ability towards cellular glutathione in human leukemic T cells

Various bis (3-aryl-3-oxo-propyl)methylamine hydrochlorides 1 and their corresponding structural and non-classical isomers 4-aryl-3-arylcarbonyl-1-methyl-4-piperidinols 3 were evaluated against human leukemic T (Jurkat) cells and found to possess significant cytotoxicity. Among the series 1 (bis-Mannich bases) and 3 (corresponding piperidinols), compounds la, 1c and 1e showed cytotoxic potency which was approximately 1.6, 3.7 and 3.4 times that of the reference drug 5-fluorouracil, respectively. Except for compound 1d, conversion of bis-Mannich bases to their corresponding piperidinols 3a, 3b and 3e lowered the potency. Besides chloro derivative 1d, bis-Mannich bases displayed greater cytotoxicity compared with their mono-Mannich bases, series 5. Representative bis-Mannich bases (1a, 1e) and piperidinols (3a, 3e) decreased the glutathione level of Jurkat cells. Molecular modeling was utilized in order to evaluate whether the shape, size, critical volume, solvent accessible area and partition coefficient of the different compounds had contributed to the varying potencies observed. Bis-Mannich bases 1a, 1c and 1e may serve as candidate anticancer agents for future development.     

Synthesis and evaluation of anticonvulsant activities of some bis Mannich bases and corresponding piperidinols

Some acetophenone derived bis Mannich bases (B1-B5) and piperidinols (C1, C4), which are the structural isomers of B1 and B4, and also quaternary piperidine derivative C6 were synthesized and studied for anticonvulsant activity. Of the compounds, C6 was reported for the first time. Chemical structures of the compounds were confirmed by UV, IR, 1H-NMR, 13C-NMR, mass spectra and elemental analysis. Their anticonvulsant activities were determined by maximal electroshock (MES), subcutaneous metrazol (scMet) tests and rotarod test for neurological deficits. According to the activity studies, B2, B4, C1 and C4 derivatives were found to be protective against MES at 30 mg/kg and above. B1, B2, B3, B4, C4 and C6 derivatives were found to be protective against scMet. at different dose levels ranging from 30 to 300 mg/kg. Since no neurotoxicity was detected for the compounds B4 and C4, they seem to be candidate compounds for further synthesis and in vivo studies for their potential anticonvulsant activity.     

Toxicity of some bis Mannich bases and corresponding piperidinols in the brine shrimp (Artemia salina) bioassay

Some acetophenone-derived bis Mannich bases were synthesized: bis[beta-benzoylethyl]ethylamine hydrochloride (IIa), bis[beta-(p-methylbenzoyl)ethyl]ethylamine hydrochloride (IIb), bis[beta-(p-chlorobenzoyl)ethyl]ethy- lamine hydrochloride (IId), bis[(2-thienylcarbonyl)ethyl]ethylamine hydrochloride (IIe); some corresponding piperidinol derivatives: 3-benzoyl-1-ethyl-4-phenyl-4-piperidinol hydrochloride (IIIa), 1-ethyl-3-(p-methyl- benzoyl)-4-(p-methylphenyl)-4-piperidinol hydrochloride (IIIb), 1-ethyl-3-(p-methoxybenzoyl)-4-(p-methoxy- phenyl)-4-piperidinol hydrochloride (IIIc), 1-ethyl-3-(p-chlorobenzoyl)-4-(p-chlorophenyl)-4-piperidinol hydrochloride (IIId), 1-ethyl-4-(2-thienyl)-3-(2-thienylcarbonyl)-4-piperidinol hydrochloride (IIIe); and some representative quaternary piperidinols: 3-benzoyl-1-ethyl-4-hydroxy-1-methyl-4-phenylpiperidinium iodide (IIIf), 1-ethyl-4-hydroxy-1-methyl-3-(p-methylbenzoyl)-4-(p-methylphenyl)piperidinium iodide (IIIg). Toxicity was tested by the brine shrimp bioassay as an intermediate test before further in vivo animal experiments. Piperidine derivatives were found to be more potent than bis Mannich bases. Quaternary piperidine derivatives IIIf and IIIg and also non-quaternary piperidine derivatives IIIb, IIIe, IIIc and IIId were more toxic than 5-fluorouracil in brine shrimp bioassay. Except for IIe, bis Mannich bases were not effective. Quaternization and conversion of bis Mannich bases to corresponding piperidines improved the toxicity. The lipid solubility of the compounds may not affect the toxicity. From these findings the quaternary piperidine derivatives IIIf and IIIg could be used in further drug development and also for in vivo experiments.     

浙新霉素对皮肤癣菌的体外抗真菌活性研究

目的：评价浙新霉素体外抗真菌活性。方法：采用CLSI推荐的M-38A方案测定浙新霉素对7种皮肤癣菌最小抑菌浓度（MIC）及最小杀菌浓度（MFC）。结果：浙新霉素对7种皮肤癣菌的MIC范围为0.125-2.000μg·ml^-1,MFC范围为0.250-4.000μg·ml^-1。结论：浙新霉素具有较强的抗真菌活性,能抑制和杀灭絮状表皮癣菌、红色毛癣菌、紫色毛癣菌、犬小孢子菌、须癣毛癣菌、断发毛癣菌、石膏样小孢子菌等多种皮肤癣菌。     

Syntheses and stability studies of some Mannich bases of acetophenones and evaluation of their cytotoxicity against Jurkat cells

Mannich bases, namely 1-aryl-3-dimethylamino-1-propanone hydrochlorides (Ia-f) as mono-Mannich bases (series I), bis(beta-aroylethyl)ethylamine hydrochlorides (IIa, IIb, IId, IIe) as bis-Mannich bases (series II), 3-aroyl-4-aryl-1-ethyl-4-piperidinol hydrochlorides (series III), which are structural isomers of bis derivatives and some representative quaternary salts (Ig, IIIf, IIIg), were synthesized to investigate the effect of chemical structure and ring substituents on cytotoxic activity in Jurkat cells. Stability studies of some representative compounds have also been realised. Compounds IIb, IId, IIe, and IIIe were reported for the first time. Id-g, IIa, IId, IIe, IIIf,g were 1.25-6.55 times more potent than 5-fluorouracil (CAS 51-21-8). However, the cytotoxic activity of the most potent compounds. Ig and IIIf, were one fifth of that of melphalan (CAS 148-82-3). The formation of compound IV during the stability studies of Ig, IIa, and IIIf suggested that they may be thiol alkylators. Bis-Mannich base IIa in nonsubstituted derivatives, piperidinol derivative IIIb in methyl substituted compounds, mono derivative Id in chloro substituted compounds were the most potent compounds when the cytotoxicity of the compound series which have the same substituents in benzene ring are compared. Replacement of the benzene with thiophene improved the cytotoxicity in both series I and II. Quaternization procedure also increased the cytotoxicity in both series I and III. Quaternary derivatives seem to be promising compounds for further studies to develop new anticancer drugs.     

Synthesis and Antifungal Activity of 1‐Aryl‐3‐phenethylamino‐1‐propanone Hydrochlorides and 3‐Aroyl‐4‐aryl‐1‐phenethyl‐4‐piperidinols

Mono‐Mannich bases, 1‐aryl‐3‐phenethylamino‐1‐propanone hydrochlorides, 1a, 2a , 3a , 4a , 5a , 6a , 7a , 8a , 9a , and semi‐cyclic mono‐Mannich bases, 3‐aroyl‐4‐aryl‐1‐phenethyl‐4‐piperidinols, 1b , 2b , 3b , 4b , 5b , 6b , 7b , 8b , 9b , were synthesized by a non‐classical Mannich reaction. The aryl part was: C₆H₅ for 1a , 1b ; 4‐CH₃C₆H₄ for 2a , 2b ; 4‐CH₃OC₆H₄ for 3a , 3b ; 4‐ClC₆H₄ for 4a , 4b ; 4‐FC₆H₄ for 5a , 5b ; 4‐BrC₆H₄ for 6a , 6b ; 2,4‐(Cl)₂C₆H₃ for 7a , 7b ; 4‐NO₂C₆H₄ for 8a , 8b ; and C₄H₃S(2‐yl) i. e., 2‐thienyl for 9a , 9b . Piperidinol compounds 2b , 3b , 4b , 5b , 7b , 8b , and 9b are reported here for the first time. The synthesized compounds were tested against seven types of plant pathogenic fungi and three types of human pathogenic fungi using the agar dilution assay. Itraconazole was tested against Candida parapsilosis as the reference compound, while Nystatin was tested as the reference compound against the other fungi. Compounds 1a , 1b , 2a , 4a , 4b , 5a , 5b , 6a , 7a , 8a , 9a , and 9b can be selected as model compounds to develop new antifungal agents against the human pathogen Microsporum canis. Compounds 8a and 8b , which had a similar antifungal activity compared with the reference compound Nystatin against the plant pathogen Aspergillus flavus, can serve as model compounds to develop new antifungal agents to solve agricultural problems.     

Studies on antifungal agents. 23. Novel substituted 3,5-diphenyl-3-(1H-imidazol-1-ylmethyl)- 2-alkylisoxazolidine derivatives

The synthesis and antifungal activity of a novel series of substituted 3,5-diphenyl-3-(1H-imidazol-1-ylmethyl)-2-alkylisoxazolidine derivatives (15-30) are described. The synthesis of the title compounds was accomplished via a 1,3-dipolar cycloaddition reaction of alpha-substituted ketonitrones with appropriate styrene precursors. The compounds when tested in vitro in solid agar cultures exerted a very potent antifungal activity against a wide variety of yeast and systemic mycoses and dermatophytes, especially Trichophyton and Microsporum sp., Epidermophyton floccosum and Candida stellatoidea. The in vitro activity against Aspergillus fumigatus and Candida albicans was moderate to potent. Overall, the two bis(4-chlorophenyl) analogues 18 and 19 were the most potent in vitro compounds, showing MIC values ranging between 0.2 and 7.0 microgram/mL, as compared to 0.2-20.0 micrograms/mL for ketoconazole, which was used as the positive standard in all assays. When tested in vivo in the rat vaginal candidiasis model, derivative 18, although showing significant antifungal activity when compared to controls, was less effective than ketoconazole. The title 3,5-substituted isoxazolidine compounds represent a novel class of potent antifungal agents.     

Cytotoxic activities of mono and bis Mannich bases derived from acetophenone against Renca and Jurkat cells

Mannich bases of acetophenones have been disclosed to have antitumour and cytotoxic activities. 1-Phenyl-3-dimethylaminopropan-1-one hydrochloride, 1, and related piperidino, 2, and morpholino, 3, derivatives, and compound 4, which is a quaternary form of 1, were synthesized as mono Mannich bases derived from acetophenone. They were converted to corresponding bis Mannich bases, 5-8, to see whether it increases the bioactivity. The biological activity of the compounds was examined by cytotoxicity against mouse renal carcinoma (Renca) and transformed human T-lymphocyte (Jurkat) cell lines. Conversion of mono Mannich bases to corresponding bis Mannich bases remarkably increased the cytotoxicity in most cases. Quaternization procedure also improved the bioactivity in mono derivatives against Jurkat cells. Bis mannich bases 5-7 were found to be more active than 5-fluorouracil (6-23 fold) and melphalan (1.25-5 fold) against Renca cells. Except 2 and 8, the compounds synthesised were found to be more active than 5-fluorouracil (1.2-33 fold) against Jurkat cells.     

Antifungal and Anti-inflammatory Activity of the Genus Echinacea

The antifungal activity and 5-lipoxygenase-inhibiting activity of extracts of five wild and three commercially used taxa of the genus Echinacea were investigated. The near-UV mediated antifungal bioassays included clinically isolated Cryptococcus neoformans, two Candida albicans isolates (D10 and CN1A) with amphotericin B resistance, as well as established and emerging filamentous fungal pathogens (Trichophyton tonsurans, T. mentagrophytes, Microsporum gypseum and Pseudallescheria boydii). Root extracts of the eight Echinacea taxa showed antifungal activity against most of the pathogenic fungi. The inhibition of the 5-lipoxygenase (5-LOX) enzyme of the arachadonic acid pathway was determined by HPLC detection of a direct metabolic product (LTB 4) of 5-LOX derived from stimulated rat basophilic cells. Root extracts of the three commercial species of Echinacea (E. purpurea, E. pallida var. angustifolia, E. pallida var. pallida) inhibited the 5-LOX enzyme. E. pallida var. angustifolia was the most potent of the three. The results show that Echinacea spp: have significant antifungal and antiinflammatory activity.     

Antifungal activity of fractions and two pure compounds of flowers from Wedelia paludosa (Acmela brasiliensis) (Asteraceae)

Wedelia paludosa (Acmela brasiliensis) (Asteraceae), a traditionally used native Brazilian medicinal plant, showed antifungal activity against dermatophytes in dilution tests. The hexane, dichloromethane and butanol fractions displayed activity against Epidermophyton floccosum, Trichophyton rubrum and Trichophyton mentagrophytes, with minimal inhibitory concentrations between 250 and 1000 microg/mL. Two pure compounds, identified as kaurenoic acid (1) and luteolin (2), also showed activity against these dermatophytes.     

1-{2-[(4-取代苯基)甲氧基]-2-(取代苯基)乙基}-1H-氮唑类化合物的合成及抗真菌活性

根据氮唑类抗真菌化合物的构效关系和作用机理,设计合成了29个1-{2-[(4-取代苯基)甲氧基]-2-(取代苯基)乙基}-1H-氮唑类化合物,其中九个为首次报道。初步体外抑菌试验结果表明,大多数目标化合物对八种试验菌株都有不同程度的抗真菌活性。化合物14对白念珠菌的活性与克霉唑及益康唑相当,对其它七种试验菌株的活性明显强于克霉唑及益康唑。化合物4,12对白念珠菌活性差,对其它七种试验菌株的活性也强于克霉唑和益康唑。化合物5,6和23除对白念珠菌外,对其它七种试验菌株,也有较强活性。     

Chemical analysis and antifungal activity of the essential oil of Calea clematidea

The chemical composition of the essential oils of Calea clematidea Baker obtained by hydrodistillation of the leaves and flowers was analysed by GC and GC/MS and the oils were assayed for their antifungal activities. The essential oil of the leaves showed a high content of a new natural epoxy terpenoid, named clemateol (ca. 70 %), with minor amounts of o-vanillin (6.5 %), spathulenol (4.2 %), alpha-terpinene (4.0 %), germacrene B (2.9 %), yomogi alcohol (1.8 %), ( E)-caryophylene (1.7 %), m-cymenene (1.6 %), and alpha-gurjunene (1.5 %), while the essential oil of the flowers was characterized by a higher content of thymol methyl ether (ca. 80 %), with minor amounts of clemateol (4.8 %) and o-cymene (4.7 %). The antimicrobial activity of the oils was also evaluated against dermatophytes for their possible use in pharmaceutical preparations for topical applications. The oil of the leaves (MIC > 3.57 mg/ml), clemateol (MIC > 1.52 mg/ml), and the alcohol 2 (MIC > 2.82 mg/ml) showed a moderate antifungal activity against Trichophyton tonsurans, Trichophyton rubrum, Trichophyton menthagrophytes var. i nterdigitale, Epidermophyton floccosum, Microsporum gypseum, Microsporum canis and Microsporum nanum.     

硫色满酮并氮杂环衍生物体外抗真菌活性及构效关系研究

对硫色满酮并氮杂环衍生物进行体外抗真菌实验,筛选具有抗真菌活性的化合物并探讨其构效关系。方法：利用微量稀释法,以氟康唑和两性霉素B为阳性对照药,测定硫色满酮类并氮杂环衍生物对白色念珠菌、新生隐球菌、断发毛癣茵、红色毛癣菌、申克孢子丝菌（菌丝相）、石膏样小孢子菌、卡氏枝孢霉、黑曲霉、絮状毛癣菌的体外抑菌活性。结果：Bb,Da,Db,I,K对絮状表皮癣菌抑制作用显著,尤其Db的MIC低于两性霉素B;K对石膏样小孢子丝菌的MIC与两性霉素B相当。二甲氨基和甲氧基取代后,抗真菌比其他取代基化合物抗真菌活性高。结论：硫色满酮并氮杂环衍生物对常见致病真菌有一定的体外抑菌活性,值得深入研究。     

Effects of Mannich bases on cellular glutathione and related enzymes of Jurkat cells in culture conditions.

Jurkat cells were exposed to representative acetophenone-derived mono Mannich bases 2 and 3 and also cyclic Mannich base C1 in culture conditions to see the alterations in the most abundant cellular thiol, glutathione and also some of the enzymes in its metabolic pathway. Jurkat cells were exposed to the compounds for 24 h in cell culture medium with fetal bovine serum (1%) at 37 degrees C under a humidified atmosphere of 95% air and 5% CO2. Mannich bases generally increased total glutathione level (123-151% of control). Glutathione S-transferase (GST) activity also increased (150-363% of control), while glutathione disulfide reductase (GRD) activity was not affected. The increase in cellular glutathione level may possibly result from de novo glutathione synthesis. The consumption of the glutathione due to alkylation by Mannich bases might have stimulated the enzymes in the gamma-glutamyl cycle in our experimental design, where the cells had nutrients and time to react with their feedback mechanisms. A remarkable increase in GST activity might be a compensatory up-regulation to detoxify Mannich bases by conjugating them with cellular thiols.     

1-{2-[(4-取代苯基)甲氧基]-2-(取代苯基)乙基}-1H-氮唑类化合物的合成及抗真菌活性

根据氮唑类抗真菌化合物的构效关系和作用机理,设计合成了29个1-{2-[(4-取代苯基)甲氧基]-2-(取代苯基)乙基}-1H-氮唑类化合物,其中九个为首次报道。初步体外抑菌试验结果表明,大多数目标化合物对八种试验菌株都有不同程度的抗真菌活性。化合物14对白念珠菌的活性与克霉唑及益康唑相当,对其它七种试验菌株的活性明显强于克霉唑及益康唑。化合物4,12对白念珠菌活性差,对其它七种试验菌株的活性也强于克霉唑和益康唑。化合物5,6和23除对白念珠菌外,对其它七种试验菌株,也有较强活性。     

Cytotoxic activities of some mono and bis Mannich bases derived from acetophenone in brine shrimp bioassay

Some mono Mannich bases (1-phenyl-3-amino-1-propanone salts) and bis Mannich bases (1-phenyl-3-amino-2-amino-methyl-1-propanone salts) derived from acetophenone and a few representative quaternary derivatives were synthesised and their cytotoxicity was tested using the brine shrimp bioassay. This assay may serve as an intermediate test before further in vivo animal experiments in large scale, since brine shrimp nauplii as whole organisms were used in this test. Mono Mannich bases were generally more cytotoxic than their corresponding bis Mannich bases. Mannich bases synthesised were cytotoxic in both brine shrimp bioassay in this study and cell culture tests using Jurkat and Renca cells in a previous study. However, the order of the cytotoxic potency of the compounds were reverse, which may result from faster deamination of bis derivatives than optimal level, and different species and test media used in the two test systems. Faster deamination of bis derivatives might have led to elimination of active metabolites before reaching its target. The cytotoxicity of the compounds might have been altered by amino acids and proteins present in cell culture medium but not in sea water used in brine shrimp bioassay affecting their transport through the cell membrane and metabolism in the cell by binding with the compounds. With higher cytotoxic activity compared with 5-fluorouracil (CAS 51-21-8) in brine shrimp bioassay, mono Mannich base 1 and its quaternary derivative 4 and quaternary bis derivative 8 seem to be candidate compounds for further drug design.