The effects of some Mannich bases on heat shock proteins HSC70 and GRP75, and thioredoxin and glutaredoxin levels in Jurkat cells

Synthesis and biological evaluation of some new mono Mannich bases with piperazines as possible anticancer agents and carbonic anhydrase inhibitors

New mono Mannich bases, (2-(4-hydroxy-3-((4-substituephenylpiperazin-1-yl)methyl)benzylidene)-2,3-dihydro-1H-inden-1-one), were prepared to evaluate their cytotoxic/anticancer properties and also their inhibitory effects on human carbonic anhydrase I and II isoenzymes (hCA I and II). Amine part was changed as [N-phenylpiperazine (1), N-benzylpiperazine (2), 1-(2-fluorophenyl)piperazine (3), 1-(4-fluorophenyl)piperazine (4), 1-(2-methoxyphenyl)piperazine (5)]. The structure of the synthesized compounds was characterized by ¹H NMR, ¹³C NMR and HRMS spectra. Cytotoxicity results of the series pointed out that the compound 4 had the highest tumor selectivity value (TS: 59.4) possibly by inducing necrotic cell death in series. Additionally, all compounds synthesized showed a good inhibition profile towards hCA I and II isoenzymes with the Ki values between 29.6 and 58.4 nM and 38.1-69.7 nM, respectively. These values were lower than the reference compound AZA. However, it seems that the compounds 4 and 2 can be considered as lead compounds of CA studies with the lowest Ki values in series for further designs.

Synthesis of mono Mannich bases of 2-(4-hydroxybenzylidene)-2,3-dihydroinden-1-one and evaluation of their cytotoxicities

Chalcones and Mannich bases are a group of compounds known for their cytotoxicities. In this study restricted chalcone analogue, compound 2-(4-hydroxybenzylidene)-2,3-dihydroinden-1-one MT1, was used as a starting compound to synthesize new mono Mannich bases since Mannich bases may induce more cytotoxicity than chalcone analogue that they are derived from by producing additional alkylating center for cellular thiols. In this study, cyclic and acyclic amines were used to synthesize Mannich bases. All compounds were tested against Ca9-22 (gingival carcinoma), HSC-2, HSC-3 and HSC-4 (oral squamous cell carcinoma) as tumour cell lines and HGF (gingival fibroblasts), HPC (pulp cells) and HPLF (periodontal ligament fibroblasts) human normal oral cells as non tumour cell lines. Cytotoxicity, selectivity index (SI) values and potency selectivity expression (PSE) values expressed as a percentage were determined for the compounds. According to data obtained, the compound MT8 with the highest PSE value bearing N-methylpiperazine moiety seems to be a good candidate to develop new cytotoxic compounds and is suited for further investigation.

Mannich bases in medicinal chemistry and drug design

The biological activity of Mannich bases, a structurally heterogeneous class of chemical compounds that are generated from various substrates through the introduction of an aminomethyl function by means of the Mannich reaction, is surveyed, with emphasis on the relationship between structure and biological activity. The review covers extensively the literature reports that have disclosed Mannich bases as anticancer and cytotoxic agents, or compounds with potential antibacterial and antifungal activity in the last decade. The most relevant studies on the activity of Mannich bases as antimycobacterial agents, antimalarials, or antiviral candidates have been included as well. The review contains also a thorough coverage of anticonvulsant, anti-inflammatory, analgesic and antioxidant activities of Mannich bases. In addition, several minor biological activities of Mannich bases, such as their ability to regulate blood pressure or inhibit platelet aggregation, their antiparasitic and anti-ulcer effects, as well as their use as agents for the treatment of mental disorders have been presented. The review gives in the end a brief overview of the potential of Mannich bases as inhibitors of various enzymes or ligands for several receptors.

Single-step synthesis of a new series of meso di-Mannich bases from the cyclic aminal (2S,7R,11S,16R)-1,8,10,17-tetraazapentacyclo[8.8.1.1.(8,17)0.(2,7)0(11,16)]icosane and p-substituted phenols

BACKGROUND

The results presented herein show that the cyclic aminal (2S,7R,11S,16R)-1,8,10,17-tetraazapentacyclo[8.8.1.1.(8,17)0.(2,7)0(11,16)]icosane (6), derived from cis-(meso)-1,2-diaminocyclohexane and formaldehyde, is a suitable substrate for the preption of a series of cis-meso Mannich bases such as 8a-l by reaction with p-substituted phenols 7a-l in basic media. These compounds are valuable synthetic products and may find application in asymmetric catalysis.

RESULTS

The products were characterized principally by NMR and IR spectroscopy. Both the benzylic and aminalic protons of the perhydrobenzimidazolidine moiety were diastereotopic due to the presence of stereogenic nitrogen centers. The occurrence of intramolecular hydrogen bonding interactions was confirmed by the broad OH stretching vibration band in the IR spectra. Vibrational spectra were calculated using B3LYP at 6-31G(d,p) level, and the calculated frequencies for the νOH vibrations were compared to those of the experimental spectra. Hydrogen bonding interactions in the solid state were observed through the X-ray crystallography of 8j. Additionally, Mulliken charges and Fukui indices for 6 were calculated as theoretical descriptors of electrophilicity.

CONCLUSION

A new series of meso Mannich bases called 4,4'-disubstituted-2,2'-{[(3aR,7aS)-2,3,3a,4,5,6,7,7a-octahydro-1H-1,3-benzimidazole-1,3-diyl]bis(methylene)} diphenols (8a-l) which are derived from cis-(meso)-1,2-diaminocyclohexane, were obtained from cyclic aminal 6. These results confirmed the behavior of 6 as an electrophilic preformed reagent in Mannich reactions in basic media.

N-(2-Benzoyl-eth-yl)propan-2-aminium chloride

In the title salt, C(12)H(18)NO(+)·Cl(-), N-H⋯Cl inter-actions between the free chloride anions and the organic cations connect the mol-ecules into hydrogen-bond dimers, forming a R(2) (2)(8) motif. The dimers are linked by C-H⋯O hydrogen bonds into chains extending along [301]. The carbonyl group is co-planar with the phenyl ring [C-C-C=O torsion angle = -3.3 (7)°]. The side chain has an E conformation.

N-[2-(4-Methyl-benzo-yl)eth-yl]propan-2-aminium chloride

In the title compound, C(13)H(20)NO(+)·Cl(-), the protonated amino N atom is hydrogen bonded to the chloride anion. N-H⋯Cl hydrogen bonds link the anions and cations into dimers, which are connected by C-H⋯O hydrogen bonds, forming supra-molecular chains extending along [100].

Synthesis and antifungal evaluation of 1-aryl-2-dimethyl- aminomethyl-2-propen-1-one hydrochlorides

The development of resistance to current antifungal therapeutics drives the search for new effective agents. The fact that several acetophenone-derived Mannich bases had shown remarkable antifungal activities in our previous studies led us to design and synthesize some acetophenone-derived Mannich bases, 1-8 and 2-acetylthiophene-derived Mannich base 9, 1-aryl-2-dimethylaminomethyl-2-propen-1-one hydrochloride, to evaluate their antifungal activities. The designed chemical structures have α,β-unsaturated ketone moieties, which are responsible for the bioactivities of the Mannich bases. The aryl part was C₆H₅ (1); 4-CH₃C₆H₄ (2); 4-CH₃OC₆H₄ (3); 4-ClC₆H₄ (4); 4-FC₆H₄ (5); 4-BrC₆H₄ (6); 4-HOC₆H₄ (7); 4-NO₂C₆H₄ (8); and C₄H₃S(2-yl) (9). In this study the designed compounds were synthesized by the conventional heating method and also by the microwave irradiation method to compare these methods in terms of reaction times and yields to find an optimum synthetic method, which can be applied for the synthesis of Mannich bases in further studies. Since there are limited number of studies reporting the synthesis of Mannich bases by microwave irradiation, this study may also contribute to the general literature on Mannich bases. Compound 7 was reported for the first time. Antifungal activities of all compounds and synthesis of the compounds by microwave irradiation were also reported for the first time by this study. Fungi (15 species) were used for antifungal activity test. Amphotericin B was tested as an antifungal reference compound. In conclusion, compounds 1-6, and 9, which had more potent (2–16 times) antifungal activity than the reference compound amphotericin B against some fungi, can be model compounds for further studies to develop new antifungal agents. In addition, microwave irradiation can be considered to reduce reaction period, while the conventional method can still be considered to obtain compounds with higher reaction yields in the synthesis of new Mannich bases.

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: C(6)H(5 )for 1a, 1b; 4-CH(3)C(6)H(4) for 2a, 2b; 4-CH(3)OC(6)H(4 )for 3a, 3b; 4-ClC(6)H(4 )for 4a, 4b; 4-FC(6)H(4) for 5a, 5b; 4-BrC(6)H(4) for 6a, 6b; 2,4-(Cl)(2)C(6)H(3) for 7a, 7b; 4-NO(2)C(6)H(4 )for 8a, 8b; and C(4)H(3)S(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.

Mechanism underlying the protective effects of glutaredoxin-1 against high glucose-induced apoptosis of umbilical vein endothelial cells

AIM: To investigate the mechanism underlying the protective effects of glutaredoxin-1 (Grx1) against high glucose-induced apoptosis of umbilical vein endothelial cells.

METHODS: The apoptosis of cultured human umbilical vein endothelial cells (HUVECs) was induced under high glucose conditions. HUVECs were then divided into three groups, namely, control group, high glucose group and Grx1 plus high glucose group. The cells were observed under an inverted light microscope to examine their morphological changes. The proliferation of cells was measured by MTT assay. The influence of Grx1 on the apoptosis of HUVECs was determined by flow cytometry with annexin V-FITC/PI double staining. The expression levels of p-JNK and p-Akt proteins were evaluated by Western blot.

RESULTS: Compared to the high glucose group, cells in the Grx1 plus high glucose group showed a significant improvement in morphology and growth state, a remarkable increase in viability (59% ± 2% vs 78% ± 3%, P < 0.05), as well as an obvious decrease in early (0.4156% ± 0.0374% vs 0.2360% ± 0.0156%, P < 0.05) and late (0.3689% ± 0.0083% vs 0.2433% ± 0.0278%, P < 0.05) apoptotic rates. Compared to the normal control group, the expression level of p-JNK protein in cells in the high glucose group significantly increased (0.48 ± 0.03 vs 0.64 ± 0.07, P < 0.05) while that of p-Akt protein significantly decreased (0.69 ± 0.11 vs 1.29 ± 0.035, P < 0.01). After pretreatment with hGrx1, the expression level of p-JNK protein decreased (0.64 ± 0.07 vs 0.39 ± 0.05, P < 0.05) while that of p-Akt protein increased (0.69 ± 0.11 vs 1.07 ± 0.13, P < 0.01).

CONCLUSION: Grx1 is able to antagonize high glucose-induced apoptosis of human umbilicus vein endothelial cells through inhibition of JNK and activation of the Akt signaling pathway.

Synthesis of 1-Aryl-3-phenethylamino-1-propanone hydrochlorides as possible potent cytotoxic agents

1-Aryl-3-phenethylamino-1-propanone hydrochlorides 1-10, which are potentialpotent cytotoxic agents, were synthesized via Mannich reactions using paraformaldehyde,phenethylamine hydrochloride as the amine component and acetophenone, 4'-methyl-, 4'-methoxy-, 4'-chloro-, 4'-fluoro-, 4'-bromo-, 2',4'-dichloro-, 4'-nitro-, 4'-hydroxyacetophenone or 2-acetylthiophene as the ketone component. Yields were in the87-98 % range. Of the compounds synthesized, compounds 2, 6-8 and 10 were new. Theoptimum reaction conditions were investigated by changing the mol ratios of the reactants,the solvents and the acidity levels using 1 and 10 as representative targets. It was observedthat the best mol ratio of the ketone, paraformaldehyde and phenethylamine hydrochloridewas 1:1.2:1 (compared with a 2:2.1 ratio), and the most suitable reaction medium wasethanol containing concentrated hydrochloric acid (compared with only ethanol or nosolvent). This study may serve as a guide for the conditions of the reactions to synthesizecompounds having similar chemical structures.