11

Recent advances on non-steroidal anti-inflammatory drugs, NSAIDs: transition metal complexes and organotin adducts of NSAIDs

Dimitra Kovala-Demertzi*

Inorganic and Analytical Chemistry, Department of Chemistry, University of Ioannina, 45100 Ioannina, Greece.

E-mail:dkovala@cc.uoi.gr

Metal-based drugs is a research area of increasing interest for inorganic, pharmaceutical and medicinal chemistry and has concentrated much attention as an approach to new drug development.

The goal is to prepare new compounds with better or different pharmacological profile than that of the free ligand.

22

Membrane Phospholipids

Phospholipase A2 / C

Arachidonic Acid

12 - Lipoxygenase

12 - HPETE

12 - HETE

PGG2

PGH2

TAX2PGI2 PGE2, PGD2, PGF2a

Cycloxygenase

5 - HPETE

LTA4

LTB4 LTC4 LTD4 LTE4

ETE

5 - Lipoxygenase

O2, .O2

-, .OH

The anti-inflammatory activity of NSAIDs and most of its other pharmacological effects are related to the inhibition of the conversion of arachidonic acid to prostaglandins, which are mediators of the inflammatory process. NSAIDs are potent inhibitors of cyclo-oxygenase in vitroand in vivo, thereby decreasing the synthesis of prostaglandins, prostacyclin, and thromboxaneproducts. Recently, two different cyclooxygenase isoforms have been characterized COX-1 and COX-2. Inhibition of the Cox-2 system results in anti-inflammatory action, while inhibition of the Cox-1 enzyme system results in anti-inflammatory action as well as gastric irritation.

HN

COOH CH3

CH3

Non-steroidal anti-inflammatory drugs, NSAIDs, from the carboxylic acid family, derivativeof N-phenylanthranilic acid, such as tolfenamic acid, diclofenac acid and mefenamic acid, andfrom the oxicam family, piroxicam, tenoxicam, meloxicam, lornoxicam and isoxicam, arewidely used in inflammatory and painful diseases of rheumatic and non-rheumatic origin.New studies from the last years revealed that in addition to arthritis and pain, cancer andneurodegenerative diseases like Alzheimer’s disease could potentially be treated with COX-2inhibitors.

HN

COOH CH3

Cl

Tolfenamic acid, HtolfMefenamic acid, Hmef

Meclofenamic Hmeclo Flufenamic, Hfluf

33

2-[(2,6-dimethylphenyl)amino]benzoic acid2-[(2-Methyl-3-nitrophenyl)amino]benzoicacid

2-[(2,6-dichlorophenyl)amino]benzoic acid

Structural representation of the dimersof HD1 and HD2

V. Dokorou, D. Kovala-Demertzi, J.P. Jasinski, A. Galani and M.A. Demertzis, Helvetica Chimica Acta, 87, 1940-1950 (2004)

The fenamates and the derivatives of substituted phenylanthranilic acid,which resembles to fenamates, were synthesized according to Ullmann-Goldberg condensation from 2- methyl-3-nitro-benzenamine and potassium 2-bromobenzoate in the presence of 4-ethylmorpholine and copper acetate

Vaso N. Dokorou , Dimitra Kovala-Demertzi, Maria Louloudi, Anca Silvestru, Mavroudis A. Demertzis, Journal of Organometallic Chemistry 693 3587–3592 (2008)

44

Organotin carboxylates form an important class of compounds and have been receiving increasing attention owing to their varied applications as catalysts and stabilizers, as biocides and as antifoulingbiocides and as antifouling agents.

New applications of such compounds are being discovered in industry, in industry, ecology and medicineecology and medicine.

In recent years, investigations have been carried out to test their anti-tumor activity and several diorganotin species, show potential as antineoplasticagents.

4SnR2O + 4HL → 2[R2LSnOSnLR2]2 + 2H2O (1)SnR2O+ 2HL→ [SnR2(L)2] + H2O (2)

The organotin adducts were obtained by azeotropic removal of water produced by the reaction between the diorganotin oxide and mefenamic acid or tolfenamic acid, flufenamic or diclofenac acid in the molar ratio 1:1 and 1:2 according to the reactions

55

The structure is centro-symmetric and features a central rhombus Sn2O2 unit with two additional tin atoms linked at the O atoms. The “external” tin atoms have their coordination geometry completed by a bridging bidentate carboxylate ligand. Five rings, each containing two tin atoms, are present in dimeric tetraorganodistannoxane 1and the geometry around the four tin centers is distorted octahedral for Sn(2) and Sn(2a) and trigonal bipyramidal for Sn(1) and Sn(1a).

For 1, the phenyl ring C(39)-C(46) of the tetramer ‘faces’ the corresponding phenyl ring of an adjacent tetramer at a distance of 3.587A showing significant π → π stacking interactions. Further, C-H—πinteractions and intramolecularhydrogen bonds stabilize the two structures. In this case,]complexes 1 is self-assembled via C-H- π and π→π stacking interactions.{V. Dokorou, Z. Ciunik, U. Russo and D. Kovala-Demertzi, J. Organom Chem., 630, 205-214 (2001)}

66

Compound [Bu2(tolf)SnOSn(tolf)Bu2]2, (2) is a centrosymmetric dimer built up around the planar cyclic Sn2O2 unit. The dihedral angles between the aminobenzoate aromatic ring and the other ring are 78.0(3)° and 47.8(2)°, respectively. Remarkably, these are comparable to the angles of 73° and 46°, respectively, found in the two white and yellow forms of free tolfenamic acid. {Kourkoumelis, N., Kovala-Demertzi, D., and Tiekink,E.R.T., Z. Kristallogr., 214 (1999) 758; Kourkoumelis, N., Ph.D. Thesis, Ioannina, 2001}

The structure is centro-symmetric and features a central rhombus Sn2O2 unit with two additional tin atoms linked at the O atoms. Six-coordinated tin centers are present in the dimerdistannoxane.The additional links between the endo- and exo-cyclic Sn atoms are providedby bridging carboxylato ligands that form asymmetrical bridges (Sn(1A)–O(1B) 2.340(5) A ˚ and Sn(1B)–O(2B) 2.204(5) A ˚ ). Each exocyclic Sn atom is also coordinated by an anisobidentatechelating carboxylato ligand (Sn(1A)–O(1A) 2.172(5)A ˚ and Sn(1A)–O(2A) 2.783(5)A ˚ ).This distance of 2.783(5) and the Sn(1B)–O(1Aa) distance of 2.871(4) A ˚ are considered long to indicate significant bonding interactions, however, the range of distances Sn–O of 2.61–3.02 A ˚has been confidently reported for intramolecular bonds

The organotin flufenamate[Me2(flu)SnOSn(flu)Me2]2

{D. Kovala-Demertzi, V. N. Dokorou, J.P. Jasinski, A. Opolski, J. Wiecek, M. Zervou, M. A. Demertzis, J. Organomet. Chem. 690 1800–1806 (2005)}

77

[Me2(Meclo)SnOSn(Meclo)Me2]2

Each pair of the central and terminal tin atoms are symmetrically bridged by the Meclo ligandthrough the carboxylate oxygens (Sn(1)– O(5) 2.220(5) Ε and Sn(2)–O(4) 2.352(4) Ε). Eachexocyclic Sn atom is also coordinated by an anisobidentate chelating carboxylate ligand (Sn(2)–O(2) 2.159(4) Ε and Sn(2)–O(3) 2.668(9) Thus the central Sn2O2 core is linked to the two outerSn2O2 rings to result a ladder-like structure. The coordination number is five and six for Sn(1) and Sn(2), respectively. The metal coordination geometry for Sn(1) is described as intermediatebetween square pyramidal and cis-trigonal bipyramidal, and for Sn(2) as distorted octahedral.

D. Kovala-Demertzi, V. Dokorou, A. Primikiri, R. Vargas, C. Silvestru, U. Russo, M. A. Demertzis, Journal of Inorganic Biochemistry, 2009

The monomers of 2 form hydrogen-bonded dimers linked by two hydrogen bonds involvingthe C(28)H hydrogen atom and the adjacent O(25) atom, and vice versa, of centro-symmetricallyrelated pairs of molecules. The observed hydrogen-bonding pattern is of the DA = AD type. Thecrystal structure of 2 shows ring stacking interactions. The monomers are stacked by a strong π-πinteraction and weaker C–H-π interactions.

D. Kovala-Demertzi, V. Dokorou, A. Primikiri, R. Vargas, C. Silvestru, U. Russo, M. A. Demertzis, Journal of Inorganic Biochemistry, 2009

88

The formation of the dimeridistannoxanes 6 and 7 represent ladder-type carboxylates in which thinsertion of μ2-OH or μ2-OC2Hgroup occurs. This unusual result canbe interpreted in terms of competition between the strengthdifferent donors, in which the –OH othe -OC2H5 groups show highedonor capacity than the carboxylatgroup of DCPA. The electronwithdrawing effect of the twchloride substituents, at 2’,3position, may be weaken the donostrength of DCPA and prevent it fromfurther condensation and thformation of the dimeritertaorganodistannoxane{D. Kovala-Demertzi, V. Dokorou, RKruszynski, T. J Bartczak, J. Wiecekand M.A. Demertzis, Z. ΑnorgΑllgem.Chem. (ZAAC) 631(12) 24812484 (2005)}}

Benzene,�reflux

ClNH

OHOCl

SnO

MeMe

MeMe Sn

OR

O

SnO

MeMeSn

OR

O

MeMe

O

OH

SnMe2O

1

CHCl3/C2H5OH SnO

MeMe

MeMe Sn

ORO

SnO

Me

MeSn

OR

O

MeMe

O

OC2H5

C2H5H

76

[R2Sn(DCPA)OSn(DCPA)R2]2.

[Bu2Sn(DMPA)2]

This crystal structure consists of discrete molecular units and the two modeprononated ligandsare co-ordinated to the SnBu2 fragment. The ligands act as anisobidentate chelating agents, thus rendering the tin atom six-coordinated. Significant π → π, C-H →π stacking interactions and intramolecular hydrogen bonds stabilize the structure. The polar imino hydrogen atom participates in intramolecular hydrogen bonds. Complexe is self-assembled via π→ π, C-H →πand stacking interactions.{{V. V. DokorouDokorou, M.A. , M.A. DemertzisDemertzis, J. P. , J. P. JasinskiJasinski, and D. , and D. KovalaKovala--DemertziDemertzi, , J. J. OrganometOrganomet. . Chem. 689 317Chem. 689 317––325 (2004)325 (2004)}}

Spectral solid and x-ray diffraction studies suggest that the stereochemistry of the complexes [SnR2(L)2] for the group of fenamatesis distorted trans-octahedral or skew-trapezoidal bipyramidal

99

O

NH

CH3

CH3

COOH

1

2

3

4

COO-K+

Br

+

NH2

CH3

Cu+2

DMF, reflux 3h

H3C

Ph3SnOH

C6H6, reflux

(molar ratio 1:1)

Sn

N

CH

H3C

Ph2Sn(molar ratio 1:1)

C6Hreflux

Ph2Sn(molar ratio 1:2)C6H

reflux

SnO

O

N

CH3

H3C

O

ON

CH3

Sn O

Ph

Ph

Sn

Sn

SnPh

Ph

C

O O

O

C

R

OO

O

C

R

R

O

C

OPh Ph

PhPh

R

CC

H3C

C

O

O

12

3

4 5 61'

2'3'4'

5'6'

2-[(2,6-dimethylphenyl)amino]benzoic acid

Ullmann-Goldberg condensation from 2,6-dimethylbenzenamine and potassium 2-bromobenzoate in the presence of 4-ethylmorpholine and copper acetate

In an attempt to prepare diphenyl derivative a relatively insoluble white solid resulted that has a high melting point, > 300 oC, and an elemental analysis indicating the loss of a benzene molecule. A facile dearylation of diphenyltin(IV) oxide takes place in the presence of mefenamic acid or tolfenamic acid.

Such dearylations have previously reported and found to have a role in the inter-conversion of phenyltin trichloroacetate complexes (AlcockNW, Roe SM. J. Chem. Soc. Dalton Trans. 1989; 1589).

• nSnPh2O + 2nHL→ [SnPh(O)L]n + nC6H6

1010

The triphenyl ester of mefenamic acid comprise discrete molecular units, in which the carboxylato group functions as an anisobidentate chelating ligand [Sn-O(1) 2.0791(18), Sn-O(2) 2.615(2)], thus rendering the tin atom five-coordinated. The intramolecular co-ordinate Sn---O(2) distance, 2.615(2) is considered long to indicate significant bonding interactions, however, the range of distances Sn--O of 2.61-3.02 Å, has been confidently reported for intramolecular bonds. The geometry at the tin atom is intermediate between square pyramidal and cis-trigonal bipyramidal, in which the carboxylato-ligand spans equatorial and axial sites.

The crystal structure of 8 shows C-H—π interactions and intramolecular hydrogen bonds. The polar imino hydrogen atoms on N(18) for 8, participates in an intramolecular hydrogen bond. [Complex 8 is self-assembled via C-H⎯π]interactions {D. Kovala-Demertzi,V. Dokorou, Z Ciunik, N. Kourkoumelis and M.A. Demertzis, Applied Organometallic Chemistry, 16, 360-368 (2002)}

1111

{D. Kovala-Demertzi, J.P. Jasinski, A. Galani and M.A. DemertzisHelvetica Chimica Acta, 87, 1940-1950 (2004)}

Tenoxicam [4-hydroxy-2,methyl-N-2-pyridyl-2H-thieno(2,3-e)-1,2-thiazine-3-carboxamide-1,1-dioxide], H2ten

Piroxicam, [4-hydroxy-2-methyl-N-pyridin-2-yl)-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide], H2pir

Lornoxicam [(8-chloro-4-hydroxy-2-methyl- 2-pyridyl-2H-thieno[2, 3-e]-1, 2-thiazine-3-amide-1,1-dioxide), H2lorn

Piroxicam is a derivative of oxicamswith a benzene ring replacing the thiophene ring in tenoxicam and Lornoxicam with a chloro atom at position 8

To date, piroxicam is among the topten NSAIDs in the market.

1212

The drugs, with four donor atoms and several possible isomers, is known to react as a monodentate ligand through the pyridyl nitrogen towards platinum(II) and as a singlydeprotonated bidentate chelate ligand, through the pyridyl nitrogen and the amideoxygen, towards copper(II) and cadmium(II)

{R. Cini, J. Chem. Soc. Dalton Trans., 1996, 111; (b) D. Di Leo, F. Berrettini and R. Cini, J. Chem. Soc. Dalton Trans., 1998, 1993; (c) R. Cini, R. Basosi, A. Donati, C. Rossi, L. Sabadini, L. Rollo, S. Lorenzini, R. Gelli and R. Marcolongo, Met. Bas. Drugs, 1995, 2, 43; (d) R. Cini, G. Giorgi, A. Cinquantini, C. Rossi and M. Sabat, Inorg. Chem., 1990, 29, 5197}

The diorganotin adducts were prepared according to the reactions (5)-(6), in benzene solutionSnR2O + H2L → [SnR2L] + H2O (5)SnR2O+ 2H2L → [SnR2(HL)2] + H2O (6)

Ortep representation of [SnMe2(lorn)] (11) and [SnBu2(lorn)] (12)

A. Galani, M. A. Demertzis, Maciej Kubicki and D. Kovala-DemertziEur. J.Inorg. Chem, 9, 1761 (2003)

1313

[SnBu2(ten)]n has 1:1 Sn:ten stoichiometry and the doubly deprotonated ligand, ten, is co-ordinated as a tridentate ligand via the enolic oxygen O(4) and the amide N(31) and pyridyl N(1’) nitrogen atoms. Two butyl carbon atoms complete five co-ordination at the diorganotin(IV) fragment. The long Sn-N(pyridyl) bond (2.426(4) Å), is readily explicable in terms of ring strain effects in the four-membered chelate ring and as a result of the low degree of covalent character of the Sn-N(pyridyl) bond. The metal co-ordination geometry is therefore described as square pyramidal with the N(31) occupying the apical position.

The isolated molecules of Sn(1) or Sn(2) are arranged in polymers in a head to tail fashion with a stacking of alternate parallel chains. Extended networks of Sn-O-Sn, C-H--O and C-H--πcontacts lead to aggregation and a supramolecularassembly.

S. K. Hadjikakou, M.A. Demertzis, J. R. Miller and D. Kovala-Demertzi,* J. Chem. Soc. Dalton Trans, 663-669 (1999)

1414

D. Kovala-Demertzi, A. Koutsodimou, A. Galani, S. K. Hadjikakou, M. A. Demertzis, M. Xanthopoulou, J. R. Miller, C.S. Frampton, Applied Organomet. Chem. 18, 501-502 (2004).

The tin atom is coordinated in a very distorted octahedral configuration through its enolateand amide oxygen atoms in a trans-Oenolate-cis-Oamide-cis-C2 configuration. The twophenyl groups are cis but the C–Sn–C angle is much greater than 90; indeed, it is closer to thetetrahedral value. In the present structure, the amide nitrogen atoms remain protonated, asthey are not coordinated.

1515

The catalytic activity of the complexes

[Me2Sn(MNAB)2] (3).

.

V.N. Dokorou, D. Kovala-Demertzi, Maria Louloudi, A. Silvestru, M. A. Demertzis, Journal ofOrganometallic Chemistry 693 (2008) 3587–3592

[Me2(MNAB)SnOSn(MNAB)Me2]2 (2).

in transesterification reactions has been studied

Cat Conc/mol%) Reaction time Yield% 2 (0.01) 1h 38.8 2 (0.01) 4h 88.5 2 (0.01) 6h 100 2 (0.01) 22h 100 3 (0.01) 1h 21.3 3 (0.01) 4h 25.1 3 (0.01) 6h 25.7 3 (0.01) 22h 100 The transesterification catalysed by 2 was normally progressed and quantitative yields were

obtained after 6 h. When the monomeric catalyst 3 was used, low yields of 25% were obtainedwithin 6 h. However, after 22 h, 3 was able to give quantitative yields as well. In all cases, theonly reaction product which has been detected was 2-phenylethylacetate.To identify the active catalytic species involved in the present reaction, small liquots of thereaction mixture were studied by LC–MS method and the analysis was performed in the negativeion mode. For reactions catalysed by 2, after 0, 2, 4 and 22 h, LC– MS spectroscopy alwaysrevealed one major product, with a very intense anion at m/z 853.5 tentatively assigned to a dianion of 2. When the catalyst 3 was used, sample analysis after 0, 2, 4 and 6 h reaction time, exhibited characteristic ions at m/z 565.4, which is the major one, and one less intense at m/z 853.5. The first anion assigned to 3 after the cleavage of the peripheral CH3 and NO2 groups ofthe organic ligand. The analysis of an aliquot after 22 h, interestingly, showed a very intenseanion at m/z 853.5 and a small one at m/z 565.4. The appearance of the peak at m/z 853.5 clearlyindicates the formation of a dimeric species analogous to 2.

The transesterification reaction of 2-phenylethanol

1616

The present findings are in accordance and further supportpreviously proposed mechanism, whereas the fundamental aspects isthe existence of an active core which involves a dimericdistannoxane. In this context, transesterification catalysed by 2, which bears such distannoxane centre, evolved progressively, andresulted in a 100% yield within 6 h. The reaction catalysed bymonomeric 3 slowed down, however, when active distannoxanecore formed, it was able to function as an efficient catalyst leadingfinally to quantitatively yields too.In conclusion, the present air and moisture stable diorganotincomplexes efficiently catalyze the transesterification reaction of 2-phenylethanol without addition of free ligand or any promotingadditive. Moreover, we have demonstrated that for the developmentof efficient catalytic systems, a distannoxane core should beinvolved into the catalyst molecule.

The stoichiometries of the complexes indicate that organotin(IV) is coordinated by the singly charged anion of Hten in SnBu2(Hten)2 and by the doubly charged anion in SnBu2(ten). {Hadjikakou, S.K.; Kovala-Demertzi, D.; Koutsodimou, A.; Kubicki, M. Helvet. Chim. Acta, 2000, 83, 2787; Angeliki Galani, M. A. Demertzis, Maciej Kubicki and D. Kovala-Demertzi Eur. J.Inorg. Chem, 9, 1761 (2003)}

Also, spectral solution studies suggest that the diorganotin adducts 1:2 lose one ligand and after rearrangement, give the 1:1 adducts according to reactions (7) for fenamates and (8) for oxicams.

4[SnR2(tolf)2 ] + 2H2O 4Htolf + [R2(tolf)SnOSn(tolf)R2]2 (7)[SnR2(Hten)2 ] [H2ten] + [SnR2(ten)] (8)

1717

Tuberculosis (TB) caused by Mycobacterium tuberculosis remains a leading cause of mortality worldwide into the 21st century. The mortality and spread of this disease has further been aggravated because of synergy of this disease with HIV. A number of anti-TB drugs are ineffective because of development of resistant strains.Internationally, efforts are being made to develop new anti-tubercular agents. There is an urgent need for new antimycobacterial agents, but no new chemotherapeutic agents directed specifically against TB have been introduced during thelast 25-30 years. TB is not an attractive target condition for the pharmaceutical industry because the majority of patients live in countries with inadequate health care budgets.

Compound Inhibition

(%)

MIC

[μg/ml]

H2tenox (9)a 21 >6.25

H2pirox (8)a 11 >6.25

H2lorno (10)a 2 >6.25

Hfluf (3)a 0 >6.25

HDMAB (5)c 0 >6.25

[Me2(dicl)SnOSn(dicl)Me2]2a 0 >6.25

[Ph2(dicl)SnOSn(dicl)Ph2]2 a 0 >6.25

[Sn(Ph)3(Flu)]a 0 >6.25

[SnPh3(mef)]b[5c] 98 0.39

[SnBu2(mef)2]b [5c] 92 >6.25

[SnMe2(dicl)2]a 100 3.13

[SnBu2(dicl)2]a 100 3.13

Selected organotin complexes and the parent ligands were screening against Mycobacterium tuberculosis H37Rv in BACTEK 12B medium using the BACTEC 460-radiometetric system at the single concentration of 6.25 μg/ml.

Biological Activities of NSAIDs and organotin complexes of NSAIDs towards Mycobacterium tuberculosis H37Rv. Alamar assay; drug concentration 6.25 mg/ml.

1818

Compound Inhibition

(%)

MIC

[μg/ml]

IC50

[μg/ml]

SI

HDMAB a

Hmeclo 0 0

>6.25 >6.25

[SnPh3(indo)]a 100 0.78 0.07 0.09

[SnPh3(tenox)]a 100 0.78 0.08 0.10

[Sn(Ph)3(DMAB)] a

[SnPh3(meclo)] 100 99

0.78 0.78

1.89 >10

2.42 >12.8

Rifampicin d 95 0.25 113.6

•The compounds which exhibited the highest inhibitory activity of 92% -100% respectively are considered as active compounds.

The compounds [SnPh3(Meclo)] and [SnPh3(DMPA)] were also tested for cytotoxicity (IC50) in Vero cells at concentrations equal to and greater than the MIC value M. tuberculosis H37Rv. The IC50 value was found to a concentration level of >10 lg/mL and 1.89 lg/mL for [SnPh3(Meclo)] and [SnPh3(DMPA)], respectively.

The selectivity index (SI = IC50/MIC) was calculated to be >12.8and 2.42 for 3 and [SnPh3(DMPA)], respectively.

[SnPh3(Meclo)] was found to be five times more activeand more selective than [SnPh3(DMPA)] and was found notonly to display a considerable anti-tuberculosis activity, but alsoto have increased cytotoxicity.

1919

Meclofenamic acid and HDMPA did no exhibit any inhibitory effectand were no screening further The interplanar angle between the twoaromatic rings is 88.2 vs. 86.7 for two conformers of HDMPA, respectively, in meclofenamic acid the corresponding angle being 81.It seems obvious that the conformation of the molecules is determinedby steric interactions between the substituents on the phenyl groups. Adjacent to the amino group in meclofenamic acid and HDMPA, thereare two equivalent Cl atoms and two Me groups, respectively, and themolecules are in a conformation where the two phenyl rings are almostperpendicular to minimize steric interactions. The dihedral anglebetween the planes of the phenyl rings of DMPA in [SnPh3(DMPA)] is68.6 and for [SnPh3(Meclo)] is 65.9(9). The best results were found forthe complex [SnPh3(Meclo)] .It seems that structural and electronic effect of the anthranilic derivativeplay important role in the activity.[SnPh3(Meclo)] is considered as an excellent lead compound and theresults of this study represent the discovery of triphenyl derivatives as a potential new class of anti-tuberculosis agent.

D. Kovala-Demertzi,V. Dokorou, Z Ciunik, N. Kourkoumelisand M.A. Demertzis, Applied Organometallic Chemistry 16, 360-368 (2002)

V. Dokorou, D. Kovala-Demertzi, J.P. Jasinski, A. Galani and M.A. Demertzi, Helvetica Chimica Acta, 87, 1940-1950 (2004)

D. Kovala-Demertzi, Journal of Organometallic Chemistry 691, 1767–1774 (2006)

D. Kovala-Demertzi, V. Dokorou, A. Primikiri, R. Vargas, C. Silvestru, U. Russo, M. A. Demertzis, Journal of Inorganic Biochemistry, 2009

2020

Meclofenamic acid and [SnPh3(Meclo)] were tested for theirantiproliferative activity in vitro against the cells of three humancancer cell lines: MCF-7 (human breast cancer cell line), T24 (bladder cancer cell line), A-549 (non-small cell lung carcinoma) andamouse fibroblast L-929 cell line.

The results of cytotoxic activity in vitro are expressed as IC50 – theconcentration of compound (in μM) that inhibits a proliferation rateof the tumor cells by 50% as compared to control untreated cell

The antiproliferative activity in vitro expressed as IC50(μM) against MCF-7, T-24, A-549 and L-929 cancer cell lines.

2121

Meclofenamic acid exhibit poor cytotoxic activity against MCF-7 and T24 cell lines and verypoor cytotoxic activity against L-929 and A-549 cell lines. The IC50 values for[SnPh3(Meclo)] against A-549 and T-24 cell lines are 0.42 and 3.23 μM, respectively, andagainst MCF-7 and L-929 cell lines are 0.43 μM and 0.18 μM, respectively. Complex [SnPh3(Meclo)] is 3.56 and 1.64 times more active than cisplatin against A-549 and L-929 cell lines, respectively. Complex [SnPh3(Meclo)] is 44.44 and 41.70 times moreactive than cisplatin against MCF-7 and T24 cell lines, respectively, and exhibited highactivity against all cell lines, more active to cisplatin against the four cell lines.

Flufenamic acid and organotin complexes [Bu2(flu)SnOSn(flu)Bu2]2 and [Bu2Sn(flu)2] wereevaluated for antiproliferative activity in vitro against A-549 lung human cancer cell line andwere found to exhibit highcytotoxic activity against A-549 (non-small cell lung carcinoma

The cytotoxic activity shown by [SnPh3(Meclo)] against L-929, A-549, MCF-7and T24 cell lines indicate that coupling of meclofenamic acid to SnPh3(IV) metal centerresult in a metallic complex with important biological properties and remarkable cytotoxicactivity, since it displays IC50 values in a μM range better to that of the anti-tumordrug cisplatin.

Thus, the complex [SnPh3(Meclo)] is considered as agent with potential anti-tumor activity, and can therefore be candidate for further stages of screening in vitro and/or in vivo.

D. Kovala-Demertzi, V. N. Dokorou, J.P. Jasinski, A. Opolski, J. Wiecek, M. Zervou, M. A. Demertzis, J. Organomet. Chem. 690 1800–1806 (2005)

D. Kovala-Demertzi, V. Dokorou, A. Primikiri, R. Vargas, C. Silvestru, U. Russo, M. A. Demertzis, Journal of Inorganic Biochemistry, 2009

2222

• The synthesis and study of metal complexes with drugs, which exhibit synergistic activity, has concentrated much attention as an approach to new drug development. A great deal is known about the role of copper complexation in enhancing the pharmacological profile of NSAID activity and reducing toxicity. Furthermore, there are suggestions that Cu may play a role in preventing the gastrointestinal damage associated with the use of the NSAIDs

• No Cu(II) anti-inflammatory drug is currently available for oral human use, although an ethanolic gel-base of Cu-salicylate (Alcusal) is available for topical temporal relief of pain and inflammation in humans. A Cu(II) dimer of indomethacin (IndoH/ 1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-Indole-3-acetic acid) with low toxicity is commercially available in Australasia, South East Asia and South Africa in a variety of oral pharmaceutical dosage forms for veterinary use.

Cu(Acac)2+2NaL->[Cu(L2)(H2O)]2MnCl2+2NaL+H2O-> [MnL2(H2FeCl3

.6H2O+2NaL-> [FeL(OH)2]2(NH4)2Fe(SO4)2.6H2O+2NaL-> [FeL2(H2O)2]CoCl2+2NaL ->[CoL2(H2O)2] NiCl2+2NaL-> [NiL2(H2O)2].2H2O

Almost all the complexes of diclofenac tested showed high anti-inflammatory activity atmolecular concentrationsmuch lower than that of diclofenac. It was suggested that the anti-inflammatory activity of diclofenac is enhanced by coordinationwith metal

Structural representation of[Cu(L2)(DMF)]2----->

D. Kovala-Demertzi, J. Inorg. Biochem., 79/1-4, 153-157 (2000)

2323

Reactions of tolfenamic and mefenamic acid

MnCl2 +2HL → [MnL2(H2O)2] + 2HClCo(CH3COO)2.4H2O + 2HL → [CoL2(H2O)2] + 2CH3COOH + 3H2ONiCl2

.2H2O + 2HL → [NiL2(H2O)2] +2HCl + H2O

Cu(CH3COO)2.H2O + 2HL → [CuL2(H2O)]2 + 2CH3COOHZnCl2 + 2HL → [ZnL2] + 2HCl

Structural representation of tolfenamic acid

[Cu(tolf)2(DMF)]2 The fourcarboxylato groups fromfour ligands are in thebidentate syn,syn η1 : η1 :μ2 bridging mode. Thr Cu-Cu bond length of 2.6075(19) Åis the shortest among thecarboxylato-bridgedbinuclear copper(II) complexes. The complex is self-assembled via C-H- πintermolecular stacking interactions

{D. Kovala-Demertzi, A. Galani, M.A. Demertzis, S. Skoulika and C. Kotoglou, J. Inorg. Βιοchem. 98 358–364 (2004)}

2424

The anti-oxidant properties of the complexes were evaluated using the 1,1-diphenyl-2-picrylhydrazyl, DPPH, free radical scavenging assay. The scavenging activities of the complexeswere measured and compared with those of the free drug and vitamin C.

The complex [Mn(mef)2(H2O)2] exhibits the highest antioxidant activity and the highestinhibitory effect against the soybean lipogygenase (LOX), properties that are not demonstrated bymefenamic acid.

Also, the complex [Mn(tolf)2(H2O)2] exhibits the antioxidant activity and a modest inhibitory effect against the soybean lipogygenase (LOX), properties that are not demonstrated by tolfenamic acid.

D. Kovala-Demertzi,* D. Hadjipavlou-Litina,* M. Staninska, A. Primikiri, C. Kotoglou and M. A. Demertzis, Journal of Enzyme Inhibition & Medicinal Chemistry JEIMC, DOI:10.1080/14756360802361589 (2008)

Effect of selected metal complexes of mefenamic and tolfenamic on swelling of the hind paw induced by Carrageenin

p< 0.1 **p< 0.01tested at 0.01 mmol/kg. *a This compound has been

86.6± 0.90.1[Pd(Tolf)2]

93.1± 0.70.1[Zn(Tolf)2.H2O]

82.6± 0.90.1[Co(tolf)2(H2O)2]

76.0± 0.80.1Tolfenamic

81.5± 1.40.1[Zn(mef)2]

17.5± 0.40.01*[Ni(mef)2(H2O)2]

71.1 ± 0.40.1[Co(mef)2(H2O)2]

61.5 ± 1.30.1Mefenamic

% inhibitionCarrageenan

Dose mmol/kg

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Their inhibitory effects on rat paw edema induced by Carrageenan was studiedand compared with those of mefenamic acid and tolfenamic acid.

The complex [Zn(mef)2] exhibited a strong inhibitory effect at 0.1 mmol/KgB.W. (81.5 % inhibition), superior to the inhibition induced by mefenamic acid atthe same dose (61.5 % inhibition).

The complex [Zn(tolf)2(H2O)] exhibited the strongest in vivo inhibitory effect at 0.1 mm/kg B.W. (93.0 ± 0.9%), superior than the inhibition induced by tolfenamic acid at the same molar dose (76.0 ± 0.9%).

Mefenamic acid, Tolfenamic acid and its metal complexes have been evaluated for antiproliferative activity in vitro against the cells of three human cancer cell lines: MCF-7 (human breast cancer cell line), T24 (bladder cancer cell line), A-549 (non-small cell lung carcinoma) and a mouse fibroblast L-929 cell line.

The copper(II) complex [Cu(mef)2(H2O)]2 displays against T24, MCF-7 and L-929 cancer cell lines, IC50 values in a μM range similar to that of the antitumor drug cis-platin and they are considered for further stages of screening in vitro and/or in vivo asagents with potential antitumor activity.

The complexes of [Mn(tolf)2(H2O)2] and [Cu(tolf)2(H2O)]2 have shown selectivity against T24 cell line. The IC50 values shown by these two complexes against T24 cancer cell lines are in a micromolar range similar or better to that of the antitumordrug cisplatin

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The antiproliferative activity in vitro of mefenamic acid its metal complexes (expressed asIC50 (M) against MCF-7, T-24, A-549 and L-929 cancer cell lines.

Compounds MCF-7

IC50 (M) x10-5

T-24

IC50 (M) x10-5

A-549

IC50 (M) x10-5

L-929

IC50 (M) x10-5

Mefenamic acid 14.92 ± 3.1 8.12 ± 4.5 16.83 ± 2.3 17.82 ± 2.8

[Mn(mef)2(H2O)2] 7.26 ± 3.5 3.51 ± 1.0 <17.56 <17.56

[Co(mef)2(H2O)2] 9.36 ± 3.0 2.70 ± 1.7 11.59 ± 2.5 <17.44

[Ni(mef)2(H2O)2] 5.93 ± 2.3 2.40 ± 1.9 8.66 ± 3.5 6.34 ± 2.2

[Cu(mef)2(H2O)]2 2.51 ± 3.3 7.77** ± 2.2 <10.03 1.95 ± 3.0

[Zn(mef)2] 4.07 ± 5.0 3.77 ± 2.0 11.12 ± 3.0 7.44 ± 1.0

Cis Pt 8.00** 41.7 ** 1.53** 0.70**

MCF-7 T-24 A-549 L-929

Tolfenamic acid 87.9±6.3 62.4±5.1 145±12 214±18

[Mn(tolf)2(H2O)2] 41.6±2.9 3.9±0.3 65.3±6.1 149±6

[Co(tolf)2(H2O)2] 44.9±3.0 38.3±1.9 76.8±7.1 33.4±2.8

[Ni(tolf)2(H2O)2] 54.5±3.3 35.30±2.1 54.1±4.9 100.1±9.1

[Cu(tolf)2(H2O)]2 26.1±2.1 13.9±1.1 31.4±2.2 5.3±0.5

[Zn(tolf)2(H2O)] 41.3±3.5 41.0±2.5 57.9±4.2 123±6

MnCl2 161±11 93.5±5.9 n.a. n.a.

CoCl2 n.a. 91.4±7.3 n.a. n.a.

NiCl2 n.a. 108±9 n.a. n.a.

CuCl2 337±22 96.7±8.7 493±3 n.a.

ZnCl2 n.a. n.a. 281±20 35.0±3.1

Cisplatin 8.0±0.8 41.7±4.5 1.5±0.1 0.7±0.1

The Antiproliferative Activity in vitro of Tolfenamic Acid and Its Metal Complexes(expressed as IC50 [μm]) against MCF-7, T-24, A-549, and L-929 Cancer Cell Lines

2727

The goal in this research was to explore the probability to extend the pharmacological profile of mefenamic and tolfenamic acid, in order to discover new properties such as anti-oxidant and anti-cancer activity, to prepare new compounds, complexes of mefenamicacid and tolfenamic acid with essential metal ions, which probably would exhibit improved or different biological behavior compared to the tolfenamic acid.

The complex [Zn(tolf)2(H2O)] and [Zn(mef)2(H2O)] may prove useful for treating of inflammatory diseases, and the complexes of [Mn(tolf)2(H2O)2] and [Cu(tolf)2(H2O)]2and [Cu(mef2(H2O)]2 may lead to the development of an antitumor drug.

Dimitra Kovala-Demertzi, Dimitra Hadjipavlou-Litina, Alexandra Primikiri, Malgorzata Staninska, Chronis Kotogloua, and Mavroudis A. Demertzis, Chemistry and Biodiversity in press (2009)

I would like to thank all my co-workers who are referred in the publications and also HELP EPE, Viannex AE and ELPEN AE for the donation of the drugs.

Dr. V. DokorouDr. N. KourkoumelisDr. A. GalaniDr. J. WiecekDr. C. KotoglouM. Staninska

Z CiunikJ.R. MillerM. Kubicki, J. Jasinski

Dr. Cecil D. KwongTuberculosis Antimicrobial Acquisition and Coordinating facility(TAACF), GWL Hansen’s Disease Center, Colorado state Universitu, Birmingham, Alabama, USA, for the in vitro evaluation of antimycobacterial activity. Prof Hadjipaylou-Litina