Bipyridine Ruthenium(II) Complexes with Halogen-Substituted Salicylates: Synthesis, Crystal Structure, and Biological Activity

Ruthenium complexes currently represent a perspective subject of investigation in terms of potential anticancer therapeutics. Eight novel octahedral ruthenium(II) complexes are the subject of this article. Complexes contain 2,2'-bipyridine molecules and salicylates as ligands, differing in position and type of halogen substituent. The structure of the complexes was determined via X-ray structural analysis and NMR spectroscopy. All complexes were characterized by spectral methods-FTIR, UV-Vis, ESI-MS. Complexes show sufficient stability in solutions. Therefore, their biological properties were studied. Binding ability to BSA, interaction with DNA, as well as in vitro antiproliferative effects against MCF-7 and U-118MG cell lines were investigated. Several complexes showed anticancer effects against these cell lines.

Evaluation of Antiproliferative Palladium(II) Complexes of Synthetic Bisdemethoxycurcumin towards In Vitro Cytotoxicity and Molecular Docking on DNA Sequence

Metallodrugs form a large family of therapeutic agents against cancer, among which is cisplatin, a paradigmatic member. Therapeutic resistance and undesired side effects to Pt(II) related drugs, prompts research on different metal-ligand combinations with potentially enhanced biological activity. We present the synthesis and biological tests of novel palladium(II) complexes containing bisdemethoxycurcumin (BDMC) 1 and 2. Complexes were fully characterized and their structures were determined by X-ray diffraction. Their biological activity was assessed for several selected human tumor cell lines: Jurkat (human leukaemic T-cell lymphoma), HCT-116 (human colorectal carcinoma), HeLa (human cervix epitheloid carcinoma), MCF-7 (human breast adenocarcinoma), MDA-MB-231 (human mammary gland adenocarcinoma), A549 (human alveolar adenocarcinoma), Caco-2 (human colorectal carcinoma), and for non-cancerous 3T3 cells (murine fibroblasts). The cytotoxicity of 1 is comparable to that of cisplatin, and superior to that of 2 in all cell lines. It is a correlation between IC50 values of 1 and 2 in the eight studied cell types, promising a potential use as anti-proliferative drugs. Moreover, for Jurkat cell line, complexes 1 and 2, show an enhanced activity. DFT and docking calculations on the NF-κB protein, Human Serum Albumin (HSA), and DNA were performed for 1 and 2 to correlate with their biological activities.

Synthesis and HPLC enantioseparation of novel derivatives of 3-alkoxy-4-hydroxyphenylalkanones of a potential α/β-blocker type

The present paper reports the synthesis of a series of seven compounds with a hetero aminopropanol chain. The compounds were prepared by the conversion of 3-alkoxy-4-hydroxyphenyl alkanones with 2-chloromethyl oxirane and subsequent reaction of the products with heterocyclic amines (pyrrolidine, azepane, 4-methylpiperazine and 2-methoxyphenyl piperazine). The target compounds were synthesized in the form of racemates. The purity of the products was confirmed by thin layer chromatography and their IR, UV-VIS and 1H-NMR spectra were recorded. Enantioseparation of the racemic products was accomplished by HPLC on a Chiralpak AD chiral chromatographic column with tris(3,5-dimethylphenyl)carbamate as the chiral selector. The efficiency of enantioseparation was determined in relation to the composition of the mobile phase (hexane : ethanol : methanol : ethylethanamine) and to the structure of the prepared compounds. Baseline separation was achieved with all compounds using mobile phases A (78 : 11 : 11 : 0,1 v/v/v/v) and B (80 : 10 : 10 : 0,1 v/v/v/v), with selectivity factor ranging from 1.07 to 1.42 and resolution from 0.76 to 5.47. The mobile phase containing a higher amount of hexane did not allow for successful enantioseparation of the piperazine derivatives.

Chiral Aspects of Local Anesthetics

Thanks to the progress made in chemical technology (particularly in the methodologies of stereoselective syntheses and analyses) along with regulatory measures, the number of new chiral drugs registered in the form of pure enantiomers has increased over the past decade. In addition, the pharmacological and pharmacokinetic properties of the individual enantiomers of already-introduced racemic drugs are being re-examined. The use of the pure enantiomer of a drug that has been used to date in the form of a racemate is called a "chiral switch". A re-examination of the properties of the pure enantiomers of racemates has taken place for local anesthetics, which represent a group of drugs which have long been used. Differences in (R) and (S)-enantiomers were found in terms of pharmacodynamic and pharmacokinetic activity as well as in toxicity. Levobupivacaine and robivacaine were introduced into practice as pure (S)-(-)-enantiomers, exhibiting more favorable properties than their (R)-(+)-stereoisomers or racemates. This overview focuses on the influence of chirality on the pharmacological and toxicological activity of local anesthetics as well as on individual HPLC and capillary electrophoresis (CE) methods used for enantioseparation and the pharmacokinetic study of individual local anesthetics with a chiral center.

Metal complexes in medicine and pharmacy - the past and the present III

Bioactive metal complexes represent a promising and rapidly evolving area of pharmacotherapy. After the first part of our survey on metallopharmaceuticals dealing with antimicrobial activity of metal complexes and their application in diagnostics and the second part dedicated to anticancer properties of these compounds, this third and last part of the review focuses on several other applications of metals in therapy (mainly on the therapy of rheumatoid arthritis, some mental diseases, diabetes, as well as on chelation therapy). Following a brief account of the historical development of clinical use of the respective category of drugs, their chemical properties, toxicity, clinical applications and mechanism of action are discussed. The aim of this brief survey is to provide basic outline of the area of metallopharmacy, aimed at specialists in pharmacy and chemistry as well as at the general educated public.

Metal complexes in medicine and pharmacy - the past and the present II

Therapy of malignant tumors is among the oldest and at the same time the most promising application areas of therapeutic metal complexes. The second part of our survey on metallopharmaceuticals deals with historical development and current state of coordination compounds in cancer therapy. It starts with the most famous and most successful metallodrug - cisplatin. After a brief account of the discovery of the anticancer properties of this substance follows the discussion of its chemical properties, toxicity, clinical application and resistance. Hereafter, complexes of other metals along with innovative research directions are addressed. The aim of this brief survey is to provide basic overview of the area of metallopharmacy, aimed at specialists in pharmacy and chemistry as well as at the general educated public.

Metal complexes in medicine and pharmacy - the past and the present I

Metals and their compounds have been exploited in medicine since the dawn of history. All metals (or their substances) exert some kind of biological activity. Metal complexes exhibit a number of unique properties as compared to purely organic substances, stemming from the presence of the metal atom and the variable arrangement of ligands around this central atom. The goal of this brief survey is to provide basic overview of the area of metallopharmacy, aimed at specialists in pharmacy and chemistry as well as at the general educated public. The first part concentrates on some historical aspects of metallopharmacy and on current application of metals in the therapy of infectious diseases and in diagnostics.

Antimicrobial Activity and Urease Inhibition of Schiff Bases Derived from Isoniazid and Fluorinated Benzaldehydes and of Their Copper(II) Complexes

In order to evaluate the influence of substitution on biological properties of Schiff bases and their metal complexes, a series of differently substituted fluorine-containing Schiff bases starting from the drug isoniazid (isonicotinylhydrazide) were prepared and their structures were established by single-crystal X-ray diffraction. Also, four copper(II) complexes of these Schiff bases were synthesized. The prepared compounds were evaluated for their antimicrobial activity and urease inhibition. Two of the Schiff bases exerted activity against C. albicans. All copper(II) complexes showed excellent inhibitory properties against jack bean urease, considerably better than that of the standard inhibitor acetohydroxamic acid.

Does stereochemistry influence transdermal permeation of flurbiprofen through the rat skin?

The possible enantioselectivity in the permeation of the chiral anti-inflammatory drug flurbiprofen across hairless rat skin was studied. The transdermal permeability of individual enantiomers from donor solution containing racemic flurbiprofen (0.1%) and pure enantiomers (0.05%) in isopropyl myristate solution was determined using side-by-side diffusion cells. The permeation profiles of enantiomers (R)- and (S)-flurbiprofen from donor solution containing racemic (RS)-flurbiprofen are comparable. When donor solution contained pure enantiomers, marked differences were observed between the permeation rates of (R)- and (S)-flurbiprofen. The steady-state flux and permeability coefficient were significantly higher for (R)-flurbiprofen in comparison with (S)-flurbiprofen (the flux ratio R/S = 2.04; p < 0.05).

[Tibiotalocalcaneal arthrodesis using a retrograde nail locked in the sagittal plane]

PURPOSE OF THE STUDY

To evaluate our experience with the use of a retrograde nail locked in the sagittal plane for tibiotalocalcaneal arthrodesis indicated in severe post-traumatic arthritis of the ankle.

MATERIAL

Twenty patients, 16 men and four women at an average age of 58.7 years (range, 23 to 72) were evaluated. All patients had severe post-traumatic changes in the talocrural and talocalcaneal joints. Five patients also had an equinus deformity. In two patients arthrodesis followed the treatment of purulent arthritis of the talocrural joint. A local fasciocutaneous flap was used for soft tissue reconstruction in three patients. All patients were operated on using the standard surgical technique. METHODS With the patient in a supine position, reamed by hand with the use of a driving rod, a straight retrograde AAN Orthofix nail was inserted through the heel bone and talus into the distal tibia and locked in these bones in the sagittal plane.

RESULTS

No complications such as injury to the neurovascular plexus or pseudoarthrosis were recorded. Four patients showed a reaction to the proximal locking screw on the proximal tibial surface, which was treated by earlier screw removal under topical anaesthesia. Due to infectious complications, the nail had to be removed prematurely in one patient. The average Foot Function Index was 12 points (range, 10 to 15) and the average ankle-hindfoot score was 67.6 points (range, 59 to 84). Thirteen patients (65 %) were not limited in their daily activities or recreational sports, six (30 %) experienced pain in sports but not daily activities and one patient (5 %) reported pain even when walking. All fusions healed in the correct position within 18 weeks.

DISCUSSION

Tibiotalocalcaneal arthrodesis is not a frequent surgical procedure in either trauma surgery or orthopaedics. For this complicated procedure, rather than intramedullary nails, internal fixation with screws or plates or external fixation are preferred. The high rate of bony healing can be explained by maintenance of exact nail locking in the sagittal plane. The antero- posterior approach provides a more secure locking in the bone and assists in neutralizing sagittal forces at the site of arthrodesis. The use of reamed interlocking nails can therefore be accepted not only for treatment of long-bone fractures, but also for treating pseudoarthrosis and in complicated or failed arthrodesis.

CONCLUSIONS

Patients' satisfaction is the primary goal we strive to achieve in severe post-traumatic conditions of the talus and foot. Repeat surgery, spongioplasty, external fixation revision for pin-tract infection, persistent pain, activity restriction and poor clinical results reduce patients' satisfaction. In our group, the rate of healed arthrodesis was high and the number of complications was low, therefore our patients' satisfaction was high.

Stereoselective determination of methadone and its main metabolite in serum and urine from methadone maintenance patients

OBJECTIVES

A stereoselective HPLC method was developed to separate and quantify both enantiomers of methadone and its main metabolite EDDP in serum and urine. The method was used to establish that there is a relationship between the dose of methadone prescribed and its serum concentration as well as urine excretion of methadone and its metabolite enantiomers.

METHODS

The chiral alpha1-glycoprotein stationary phase was used for enantioseparation of (R)-methadone, (S)-methadone and (R)-EDDP (S)-EDDP. The enantiomers of methadone and EDDP were extracted from urine and serum by a simple solidphase procedure.

RESULTS

The validated method was applied to the analysis of 31 serum and urine samples obtained from methadone-maintained outpatients (65% male, age 28.8+/-4; methadone dose 146+/-47 mg). A significant correlation (Pearson) r=0.67 (p<0.001) between methadone dose and serum concentration of (R)-methadone was found. Due to the large variation in results obtained from analysis of the subjects' urine specimens, no statistically significant relationship between methadone dose and urine excretion of methadone and EDDP enantiomers was established. The rate of R/S methadone (1.38 in serum, 2.43 in urine) and R/S EDDP (0.83 in urine) confirmed stereoselectivity in methadone metabolism with high individual variability.

CONCLUSIONS

The enantioselective evaluation of serum methadone concentration might be an interesting tool in methadone maintenance programme. On the other hand, the urinary excretion of methadone and EDDP enantiomers is not reliable as marker of methadone compliance but could be useful for monitoring individual metabolism or for studying the stereoselectivity in pharmacokinetics and metabolism of methadone.

Antilipoxygenase activity of copper complexes of aminoalkanoate type

OBJECTIVES

Lipoxygenases (EC 1.13.11.12, LOX) catalyze the hydroperoxidation of polyunsaturated fatty acids (PUFA). This reaction leads to the production of conjugated hydro peroxide dienes of PUFA. In animals, LOX generate leukotriens (LT) and lipoxins, which belong to inflammatory mediators. It is believed that restricting LT synthesis by inhibition of LOX would have therapeutic utility for the treatment of a variety of inflammatory conditions (e.g. asthma, rheumatoid arthritis, psoriasis).

METHODS & RESULTS

The process of production and elimination of radical intermediates in vitro can be monitored by determination of LOX activity. We assessed the concentration of PUFA hydroperoxides in our system with LOX-catalyzed enzyme reaction spectrophotometrically. The inhibition of LOX activity (LOX from cytosol fraction of rat lungs) with selected N-salicylideneaminoalkanoatocopper(II) complexes was tested. In our experiments, all compounds tested showed an inhibitory effect on LOX catalyzed hydroperoxidation of PUFA. Cu(II) (from CuSO(4).5H(2)O dilution) ions also inhibited this enzyme reaction, but all compounds studied had a 10 times higher anti-LOX activity. The most effective of these complexes was monohydrate aqua-(N-salicylidene-L-a-alaninato)copper(II) complex [Cu(sal-L-alpha-ala)(H(2)O)].H(2)O with IC(50) 1.86 x 10(-4) mol/l.

CONCLUSIONS

These complexes are known for their anti-phlogistic and radioprotective properties and they can be classified as potential anti-radical compounds. The structure of these complexes is similar to the active site of Cu,Zn-SOD (superoxide dismutase) and superoxide radical scavenger activity of these complexes is known. We found that these copper complexes were capable to inhibit LOX activity, which may be related with their anti-radical properties.

[Blockers of beta-adrenergic receptors--a group of chiral agents stereoselective synthesis of beta-blockers]

Besides chromatographic methods and biocatalyzed reactions, another alternative method of obtaining enantiomeric forms of beta-blockers is stereoselective synthesis. This paper links up with two preceding surveys concerning beta-blockers--groups of chiral agents and presents a survey of the hitherto published enantioselective syntheses of (R)- and (S)-enantiomers of beta-blockers. In the group of arylaminoethanols, mainly selective reduction of prochiral ketones in the presence of metallic complexes is used in this type of synthesis. Enantiomerically pure beta-blockers of the aryloxyaminopropanol type are synthesized by means of a reaction of pertinent phenols with different chiral precursors, such as (R) and (S)-chloromethyloxirans, (S)-glycidoltosylate, (S)- or (R)-2,3-O-isopropylideneglyceroltosylate, E-(2S,3S)-3-trimethylsilylglycidol and (S)-3-terc-butyl-5-phenyl-oxazolidine-5-ylmethanol. Many of these chiral semiproducts can be prepared from natural substances, such as D-mannitol and L-ascorbic acid.

[Chiral switch: pure enantiomers of drugs instead of racemic mixtures]

Chirality of drugs, particularly the comparison of efficacy of enantiomers and their racemic mixtures, has become an object of serious interest of pharmaceutical researchers in recent ten or fifteen years. Advances in chemical technologies connected with the synthesis, separation, and analysis of pure enantiomers from racemates, together with administrative regulatory measures, have resulted in an increase in the number of newly registered chiral drugs containing only one of the enantiomers. Besides new chemical entities, many "old" racemates are being re-evaluated as potentially new sources of pure enantiomers which should improve the therapeutic profile of the drug. Due to this replacement of a racemic mixture with a pure enantiomer, the literature lists both drugs containing a racemate and drugs containing only one of the enantiomers. Nevertheless, the required therapeutic effect is not always achieved, and unexpected undesirable effects have also occurred. The paper summarizes therapeutic and economic problems concerning chiral switch drugs.

Antiradical activity of different copper(II) Schiff base complexes and their effect on alloxan-induced diabetes

Considering the important role of antioxidants in biological systems, the group of copper(II) complexes derived from salicylaldehyde and alpha- or beta-alanine and its thiourea derivative and copper(II) complexes derived from pyruvic acid and beta-alanine were studied. The antiradical activity of the tested compounds was studied by both in vitro and in vivo methods. The chemical methods based on inhibition of INT-formazane or 3-nitrotyrosine formation were used for the evaluation of SOD-mimic and antiperoxynitrite activity, respectively. In the case of in vivo activity evaluation, an alloxan-induced diabetes mellitus model in mice was used, the mechanism of action of alloxan being closely connected with the formation of free radicals selectively damaging the pancreatic beta-cells. Since all the substances studied showed different positive effects, it is obvious that they have not acted only as a source of copper(II) ions but their effect is related to their specific chelate structure. The obtained results are a contribution to the knowledge of copper(II) Schiff base complexes with ligands of aldimine or ketimine type and form the basis for further preclinical tests of these bioactive agents in biological models of oxidative stress.

[Adrenergic beta-receptor blockers--a group of chiral drugs: enantioseparation in the group of beta-blockers]

The preparation of pure individual enantiomers represents a topical problem from the standpoint of efficacy and safety of drugs. This paper continues in the preceeding review of the blockers of beta-adrenergic receptors as a group of chiral drugs, which is concerned with different pharmacodynamic, pharmacokinetic, and toxicological effects of individual enantiomers of this group. The review paper pays attention to the problems of enantioseparation of this group of chiral drugs, listing individual examples of the methods of enantioseparation, such as crystallization, biocatalysis, chromatographic methods (HPLC, GC, TLC), capillary electrophoresis, and the method of nuclear magnetic resonance (NMR). The individual methods of enantioseparation including enantioseparation in biological material (urine, serum) are illustrated on examples on beta-blockers used in clinical practice (e.g., propranolol, atenolol, metoprolol) as well as potential agents of this group of drugs.

[Radioprotective effects of basic copper carboxylate complexes]

The radioprotective activity of eight selected copper (II) carboxylates--Cu (RCOO)2.nL (R = alkyl, aryl, 2-furyl and 2-thienyl; L usually represents water)--was assayed in a model of lethally gamma-irradiated (9 Gy, 0.97 Gy/min) mice. The compounds tested were applied (as solutions in saline) s.c. in three single doses of 20 mumol/kg 48.24 and 6 h before irradiation. The highest radioprotective effects were measured by survival of mice achieved after premedication of animals with copper (II) 2-thenoate monohydrate (77%), copper (II) acetylsalicylate (64%), copper (II) 2-methoxybenzoate monohydrate (62%) and copper (II) acetate monohydrate (54%). On the other hand, survival of vehicle-pretreated mice was only 10%. The observed biological properties of complexes are discussed in relation to their structures.

[Anti-ulcer effectiveness of mono- and dibasic carbamates with local anesthetic effects]

An evaluation of anti-ulcer effects of mono- and dibasic carbamate local anaesthetics was performed using two experimental models of gastric ulcers, i.e. those induced by stress, or by ligation of the pylorus. These models have been found not to be identical. In the case of stress-induced ulcers, no experimental animal died as compared to the second experimental group with a 30% mortality rate due to the more frequent occurrence of ulcer perforations. Result similarities of both models could only be found with respect to the range of damage of the mucous membrane of the stomach. A premedication with a majority of basic carbamates decreased the incidence and range of ulcer lesion. The anti-ulcer activity of monobasic carbamates was more significant when compared with dibasic compounds.

The influence of carbamate local anesthetics on the occurrence of experimental gastric ulcers

Evaluation of the antiulcer effects of a series of 2-piperidineethylesters of o-alkoxy-substituted phenylcarbamic acids were performed using two experimental models of gastric ulcers, e.g. induced by stress or by ligation of the pylor. It was found that these models were not identical. In the case of stress-induced ulcers, no experimental animal died as compared to the second experimental group with a 30% mortality rate due to the more frequent occurrence of ulcer perforations. Result similarities of both models could only be found with respect to the range of damage of the mucous membrane of the stomach. A premedication of rat with basic carbamates in the dose 20 mg.kg-1 p.o. resulted in a reduced incidence of stress- and ethanol-induced ulcerous lesions. The most significant antiulcer activity was found using compounds designated as the No. XIII, XVI and XIX. Pretreatment of rats with basic carbamates in the case of Shay ulcers has again resulted in a reduced range of ulcer lesions which was most expressive using compounds No. XVI and XIX.