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Marijana Končič, Zrinka Rajič, Neva Petrič and Branka Zorc

Antioxidant activity of NSAID hydroxamic acids

In the present study, seven hydroxamic acid derivatives of nonsteroidal anti-inflammatory drugs (NSAIDs) (ibuprofen, fenoprofen, ketoprofen, indomethacin and diclofenac) were found to possess significant antioxidant, radical scavenging and metal chelating activities. The most active antioxidant and radical scavenger was N-methylhydroxamic acid of diclofenac (ANT = 88.0% and EC 50 = 60.1 μg mL-1). The activity of the standard substance, butylated hydroxyanisole, in the two assays was ANT = 86.9% and EC 50 = 18.8 μg mL-1, respectively. Ibuproxam was the strongest iron chelator among investigated hydroxamic acids (EC 50 = 255.6 μg mL-1), yet significantly weaker than the standard substance, EDTA (EC 50 = 29.1 μg mL-1). It seems that different mechanism is involved in metal chelating activity than in antioxidant and radical scavenging activity. Antioxidant and radical scavenging activities may be connected with conjugation of the nitrogen lone electron pair with the carbonyl group. On the other hand, more hydrophilic substances tend to be better iron chelators.

Open access

Ivana Perković, Zrinka Rajić Džolić and Branka Zorc

Abstract

A convenient synthetic method for the preparation of novel NSAID twin esters 6a-i containing amino acid residue, urea and amide moieties has been developed. The synthetic pathway applied for the preparation of target compounds and key intermediates 1-benzotriazolecarboxylic acid chloride (1), NSAID benzotriazolides 2a-c and N-(1-benzotriazolecarbonyl)-amino acids 3a-d involved benzotriazole as a synthetic auxiliary. The final preparation step of esters 6a-i included the solvent-free reaction of compounds 2a-c with amino acid derivatives 5a-g, bearing two hydroxyl groups, one at each terminal, beside urea and amide functionalities.

Open access

Zrinka Rajić, Gabrijela Kos, Branka Zorc, Prati Singh and Savita Singh

Macromolecular prodrugs. XII. Primaquine conjugates: Synthesis and preliminary antimalarial evaluation

New primaquine conjugates 5-7 with glucosamine and two polymers of polyaspartamide type, poly[α,β-(N-2-hydroxyethyl-DL-aspartamide)] (PHEA) and poly[α,β-(N-3-hydroxypropyl-DL-aspartamide)] (PHPA), were synthesized, characterized and screened for their antimalarial activity. The conjugates differed in the type of covalent bonding, length of the spacer between the polymeric carrier and drug, molecular mass and drug-loading. Blood-schizontocidal activity of the prepared conjugates was tested against Plasmodium berghei infection in Swiss mice. Polymeric conjugates showed better antimalarial activity than the glucosamine conjugate.

Open access

Zrinka Premužić, Petra Rajić Šikanjić and Anita Rapan Papeša

Abstract

The Avar period cemetery of Nuštar, situated in continental Croatia, is dated to the 8th and the beginning of the 9th century. Rescue archaeological excavation yielded 196 burials. During analysis of human skeletal remains, an individual with a large cranial lesion caused by trepanation was found. Trepanation is a surgical procedure performed on the skull in order to remove a fragment of the bone using a sharp instrument or drill. It has been practiced in various regions since the prehistoric period for both medical and ritual reasons. The aim of this paper is to provide a description of the observed lesion based on macroscopic appearance accompanied by radiography, computed tomography scanning and 3D optical scanning. Furthermore, possible cause and employed technique are taken into consideration, as well as cultural and historical implications of the case.

Open access

Zrinka Rajić, Marijana Končić, Kristina Miloloža, Ivana Perković, Ivan Butula, Franz Bucar and Branka Zorc

Primaquine-NSAID twin drugs: Synthesis, radical scavenging, antioxidant and Fe2+ chelating activity

Novel primaquine conjugates with non-steroidal anti-inlammatory drugs (PQ-NSAIDs, 4a-h) were prepared, fully chemically characterized and screened for radical scavenging and antioxidant activities. The synthetic procedure leading to twin drugs 4a-h involved two steps: i) preparation of NSAID benzotriazolides 3a-h from the corresponding NSAID (ibuprofen, ketoprofen, fenoprofen, ketoprofen hydroxy and methylene analogues, diclofenac or indomethacin) and benzotriazole carboxylic acid chloride (BtCOCl, 1), ii) reaction of intermediates 3a-h with PQ. The prepared PQ-NSAIDs exerted moderate activities in the DPPH free radical test and β-carotene-linoleic acid assay. Moreover, ketoprofen derivatives 4d and 4b demonstrated a notable Fe2+ chelating ability as well. On the other hand, negligible antiproliferative and antituberculotic effects of conjugates 4a-h were observed.

Open access

Kristina Pavić Zrinka Rajić, Zvonimir Mlinarić, Lidija Uzelac, Marijeta Kralj and Branka Zorc

Abstract

In the current paper, we describe the design, synthesis and antiproliferative screening of novel chloroquine derivatives with a quinoline core linked to a hydroxy or halogen amine through a flexible aminobutyl chain and urea spacer. Synthetic pathway leading to chloroquine urea derivatives 4-10 includes two crucial steps: i) synthesis of chloroquine benzotriazolide 3 and ii) formation of urea derivatives through the reaction of compound 3 with the corresponding amine. Testing of antiproliferative activity against four human cancer cell lines revealed that chloroquine urea derivatives 9 and 10 with aromatic moieties show activity at micromolar concentrations. Therefore, these molecules represent interesting lead compounds that might provide an insight into the design of new anticancer agents.