Synthesis, characterization and ROS-mediated cytotoxic action of novel (S,S)-1,3-propanediamine-N,N′-di-2-(3-cyclohexyl)propanoic acid and corresponding esters

Newly synthesized palladium(II) complexes with dialkyl esters of (S,S)-propylenediamine-N,N'-di-(2,2'-di-(4-hydroxy-benzil))acetic acid: in vitro investigation of biological activities and HSA/DNA binding

The four new ligands, dialkyl esters of (S,S)-propylenediamine-N,N'-di-(2,2'-di-(4-hydroxy-benzil))acetic acid (R2-S,S-pddtyr·2HCl) (R = ethyl (L1), propyl (L2), butyl (L3), and pentyl (L4)) and corresponding palladium(II) complexes have been synthesized and characterized by microanalysis, infrared, 1H NMR and 13C NMR spectroscopy. In vitro cytotoxicity was evaluated using the MTT assay on four tumor cell lines, including mouse mammary (4T1) and colon (CT26), and human mammary (MDA-MD-468) and colon (HCT116), as well as non-tumor mouse mesenchymal stem cells. Using fluorescence spectroscopy were investigated the interactions of new palladium(II) complexes [PdCl2(R2-S,S-pddtyr)]; (R = ethyl (C1), propyl (C2), butyl (C3), and pentyl (C4)) with calf thymus human serum albumin (HSA) and DNA (CT-DNA). The high values of the binding constants, Kb, and the Stern-Volmer quenching constant, KSV, show the good binding of all complexes for HSA and CT-DNA. The mentioned ligands and complexes were also tested on in vitro antimicrobial activity against 11 microorganisms. Testing was performed by the microdilution method, where the minimum inhibitory concentration (MMC) and the minimum microbicidal concentration (MMC) were determined.

Synthesis, characterization, HSA binding, molecular docking, cytotoxicity study, and antimicrobial activity of new palladium(II) complexes with propylenediamine derivatives of phenylalanine

The four new ligands, propylenediamine derivatives of phenylalanine (R2-S,S-pddbaˑ2HCl; L1-L4) and their palladium(II) complexes (C1-C4) were synthesized and characterized by elemental analysis, infrared, 1H and 13C NMR spectroscopy. The interactions of new palladium(II) complexes with human serum albumin (HSA) were studied by fluorescence spectroscopy. All investigated compounds can be transported to target cells by binding to HSA, but complex C4 interacts most strongly. Molecular docking simulations were applied to comprehend the binding of the complex to the molecular target of HSA. Obtained results are in good correlations with experimental data regarding binding affinity by HSA. In vitro cytotoxicity activities were investigated on four tumor cell lines (mouse mammary (4 T1) and colon (CT26), human mammary (MDA-MD-468) and colon (HCT116)) and mouse mesenchymal stem cells as non-tumor control cells. Cytotoxic capacity was determined by MTT test and according to obtained results ligand L4 stands out as the most active and selective compound and as a good candidate for future in vivo testing. Further examination of the ligand L4 and corresponding complex C4 led to the conclusion that both induced cell death mainly by apoptosis. Ligand L4 facilitated cycle arrest in G0/G1 phase and decreased proliferative capacity of tumor cells. In vitro antimicrobial activity for ligands and corresponding Pd(II) complexes was investigated against eleven microorganisms (eight strains of pathogenic bacteria and three yeast species) using microdilution method. The minimum inhibitory concentration and minimum microbicidal concentration were determined.

Non-uniformity in in vitro drug-induced cytotoxicity as evidenced by differences in IC50 values - implications and way forward

Cell lines have proven indispensable for in vitro experiments and their utility as experimental models range from understanding the fundamental cell functioning to drug discovery. One of the most common utility of cell lines is for in vitro drug testing. Drug testing involves determining the cytotoxic effects of the drugs and such a measurement is expressed as the IC₅₀ values of drugs. Although determination of IC₅₀ values of drugs on cell lines is one of the most common in vitro experimental approaches, a significant amount of variations can be observed in the results obtained from such studies. Although the variations in the IC₅₀ values of a drug on different cells lines can and should vary, the non-uniformity of such results reported from different studies using a particular drug on a specific cell line is a matter of concern. We present the IC₅₀ values of 5 most commonly used drugs 5-fluorouracil, bleomycin, cisplatin, doxorubicin and methotrexate obtained from several in vitro cell line-based studies. Some of the factors which contribute to the non-uniformity of the IC₅₀ values for a particular drug from different studies are discussed as three types of factors, the biological, non-biological and human factors. Also, ways in which such variations can be reduced to obtain universally common, reliable results are presented.

Selected polyoxopalladates as promising and selective antitumor drug candidates

Polyoxo-noble-metalates (PONMs), a class of molecular noble metal-oxo nanoclusters that combine features of both polyoxometalates and noble metals, are a promising platform for the development of next-generation antitumor metallodrugs. This study aimed to evaluate the antitumor potential against human neuroblastoma cells (SH-SY5Y), as well as toxicity towards healthy human peripheral blood cells (HPBCs), of five polyoxopalladates(II): (Na₈[Pd₁₃As₈O₃₄(OH)₆]·42H₂O (Pd₁₃), Na₄[SrPd₁₂O₆(OH)₃(PhAsO₃)₆(OAc)₃]·2NaOAc·32H₂O (SrPd₁₂), Na₆[Pd₁₃(AsPh)₈O₃₂]·23H₂O (Pd₁₃L), Na₁₂[SnO₈Pd₁₂(PO₄)₈]·43H₂O (SnPd₁₂), and Na₁₂[PbO₈Pd₁₂(PO₄)₈]·38H₂O (PbPd₁₂)), as the largest subset of PONMs. A pure inorganic, Pd₁₃, was found as the most potent and selective antineuroblastoma agent with IC₅₀ values (µM) of 7.2 ± 2.2 and 4.4 ± 1.2 for 24 and 48 h treatment, respectively, even lower than cisplatin (28.4 ± 7.4 and 11.6 ± 0.8). The obtained IC₅₀ values (µM) for 24/48 h treatment with SrPd₁₂ and Pd₁₃L were 75.8 ± 6.7/76.7 ± 22.9 and 63.8 ± 3.6/21.4 ± 10.8, respectively, whereas SnPd₁₂ and PbPd₁₂ did not remarkably affect the SH-SY5Y viability (IC₅₀ > > 100 µM). Pd₁₃ caused depolarisation of inner mitochondrial membrane prior to superoxide ion hyperproduction, followed by caspase activation, DNA fragmentation and cell cycle arrest, all hallmarks of apoptotic cell death, and accompanied by an increase in acidic vesicles content, suggestive of autophagy induction. Importantly, Pd₁₃ demonstrated the antitumor effect at concentrations not cytogenotoxic for normal HPBCs. On the contrary, SrPd₁₂ and Pd₁₃L at concentrations ≥ 1/3 IC₅₀ (24 h) decreased HPBC viability and increased % tail DNA up to 42% and 3.05 times, respectively, related to control. SnPd₁₂ and PbPd_12, previously confirmed promising antileukemic agents, did not exhibit cytogenotoxicity to HPBCs, and thus could be regarded as tumor cell specific and selective drug candidates.

Estimation of passive gastrointestinal absorption and membrane retention using PAMPA test, quantitative structure-permeability and quantitative structure-retention relationship analyses of ethylenediamine-N,N'-di-2-(3-cyclohexyl)propanoic acid and 1,3-propanediamine-N,N'-di-2-(3-cyclohexyl)propanoic acid derivatives

Passive gastrointestinal absorption and membrane retention of twelve esters of (S,S)-ethylenediamine-N,N'-di-2-(3-cyclohexyl)propanoic acid (EDCP) and (S,S)-1,3-propanediamine-N,N'-di-2-(3-cyclohexyl)propanoic acid (PDCP), as well as of these two non-esterified acids were estimated using PAMPA test. Artificial PAMPA membrane used in this study for the simulation of gastrointestinal barrier was solution of egg lecithin in dodecane (1 % w/v). All tested compounds belong to class III (high membrane retention and low permeation), whereas EDCP, dipentyl ester of PDCP (DPE-PDCP) and diisopentyl ester of PDCP (DIPE-PDCP) belong to class I (negligible membrane retention and low permeation). Finally, quantitative structure - permeability and structure - retention relationships models were created in order to find quantitative relationships between physico-chemical properties of tested compounds and PAMPA membrane permeability/membrane retention parameters. Statistically the most reliable models were analysed and used for the design of new compounds for which favourable membrane permeability and retention can be expected.

Current Development of Metal Complexes with Diamine Ligands as Potential Anticancer Agents

Background::

The discovery of cisplatin and the subsequent research revealed the importance of dinitrogen-containing moiety for the anticancer action of metal complexes. Moreover, certain diamine ligands alone display cytotoxicity that contributes to the overall activity of corresponding complexes.

Objective::

To summarize the current knowledge on the anticancer efficacy, selectivity, and the mechanisms of action of metal complexes with various types of diamine ligands.

Method::

The contribution of aliphatic acyclic, aliphatic cyclic, and aromatic diamine ligands to the anticancer activity and selectivity/toxicity of metal complexes with different metal ions were analyzed by comparison with organic ligand alone and/or conventional platinum-based chemotherapeutics.

Results::

The aliphatic acyclic diamine ligands are present mostly in complexes with platinum. Aliphatic cyclic diamines are part of Pt(II), Ru(II) and Au(III) complexes, while aromatic diamine ligands are found in Pt(II), Ru(II), Pd(II) and Ir(III) complexes. The type and oxidation state of metal ions greatly influences the cytotoxicity of metal complexes with aliphatic acyclic diamine ligands. Lipophilicity of organic ligands, dependent on alkyl-side chain length and structure, determines their cellular uptake, with edda and eddp/eddip ligands being most useful in this regard. Aliphatic cyclic diamine ligands improved the activity/toxicity ratio of oxaliplatin-type complexes. The complexes with aromatic diamine ligands remain unexplored regarding their anticancer mechanism. The investigated complexes mainly caused apoptotic or necrotic cell death.

Conclusion::

Metal complexes with diamine ligands are promising candidates for efficient and more selective alternatives to conventional platinum-based chemotherapeutics. Further research is required to reveal the chemico-physical properties and molecular mechanisms underlying their biological activity.

The medicinal uses, toxicities and anti-inflammatory activity of Polyalthia species (Annonaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Polyalthia is one of the largest and notable genera in Annonaceae family. Polyalthia species have been widely used in folklore medicine for the treatment of rheumatic fever, gastrointestinal ulcer and generalized body pain. Numerous in vitro and in vivo studies on Polyalthia Species have also corroborated the significant anti-inflammatory potential of its extracts and secondary metabolites.

AIM OF THE STUDY

This review is an attempt to assess the anti-inflammatory activity of Polyalthia species by giving critical appraisal and establishing evidences of their traditional uses. Moreover this review will highlight the lead compounds for future drug development that can serve as a potential anti-inflammatory drug with comparative efficacy and minimum side effects.

MATERIALS AND METHODS

An extensive literature review, focusing the anti-inflammatory potential of Polyalthia species was conducted using the following databases:PubMed, ScienceDirect, SpringerLink, Ovid, Scopus and ProQuest, as well as the locally available books, journals and relevant documents. The reference lists of retrieved papers were also searched for additional studies.

RESULTS

The Polyalthia species have shown significant anti-inflammatory activity through various mechanism of action. The most significant anti-inflammatory mechanism includes the inhibition of nuclear factor kappa B (NF-κB), prostaglandins (PGs), pro-inflammatory cytokines, inducible nitric oxide synthase (iNOS) and reactive oxygen species (ROS). The data suggests that hydroxycleroda-3,13-dien-15,16-olide and 16-oxocleroda-3,13-dien-15-oic acid, quercetin, rutin, spinasterol, α-spinasterol, goniothalamin and (-)-5-hydroxygoniothalamin are the most potent anti-inflammatory compounds from Polyalthia species with comparable IC₅₀ with positive controls.

CONCLUSIONS

Numerous pharmacological studies have supported the use of Polyalthia species against pain, rheumatic fever, haemorrhages and inflammation in traditional medicine. Flavonoids, diterpenoids, sterols and styrylpyrones from genus Polyalthia are the most significant class of compounds with potent anti-inflammatory activity. Secondary metabolites from these classes should be brought into further research to fill the gaps of knowledge in pharmacokinetics, pharmacodynamics, bioavailability, and toxicity in order to convert the pre-clinical results into clinical data for further investigation.

In vitro and in vivo antimelanoma effect of ethyl ester cyclohexyl analog of ethylenediamine dipropanoic acid

Melanoma, an aggressive skin tumor with high metastatic potential, is associated with high mortality and increasing morbidity. Multiple available chemotherapeutic and immunotherapeutic modalities failed to improve survival in advanced disease, and the search for new agents is ongoing. The aim of this study was to investigate antimelanoma effects of O,O-diethyl-(S,S)-ethylenediamine-N,N'di-2-(3-cyclohexyl) propanoate dihydrochloride (EE), a previously synthesized and characterized organic compound. Mouse melanoma B16 cell viability was assessed using acid phosphatase, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, sulforhodamine B, and lactate dehydrogenase assays. Apoptosis and autophagy were investigated using flow cytometry, fluorescence and electron microscopy, and western blotting. In vivo antitumor potential was assessed in subcutaneous mouse melanoma model after 14 days of treatment with EE. Tumor mass and volume were measured, and RT-PCR was used for investigating the expression of autophagy-related, proapoptotic, and antiapoptotic molecules in tumor tissue. Investigated organic compound exerts significant cytotoxic effect against B16 cells. EE induced apoptosis, as confirmed by phosphatidyl serine externalisation, caspase activation, and ultrastructural features typical for apoptosis seen on fluorescence and electron microscopes. The apoptotic mechanism included prompt disruption of mitochondrial membrane potential and oxidative stress. No autophagy was observed. Antimelanoma action and apoptosis induction were confirmed in vivo, as EE decreased mass and volume of tumors, and increased expression of several proapoptotic genes. EE possesses significant antimelanoma action and causes caspase-dependent apoptosis mediated by mitochondrial damage and reactive oxygen species production. Decrease in tumor growth and increase in expression of proapoptotic genes in tumor tissue suggest that EE warrants further investigation as a candidate agent in treating melanoma.