Elsevier

Il Farmaco

Volume 58, Issue 9, September 2003, Pages 823-828
Il Farmaco

Antioxidant activity of thioureidic derivatives I

https://doi.org/10.1016/S0014-827X(03)00139-3Get rights and content

Abstract

Recent developments in biomedical science have shown that free radicals are involved in many diseases. They attack the unsaturated fatty acids in the biomembrane resulting in membrane lipid peroxidation, which is strongly connected to aging, carcinogenesis and atherosclerosis. Free radicals also attack DNA and cause mutation leading to cancer. In addition lipid peroxidation is an important factor of deterioration in the processing and storage of food. Therefore, it is important to search for new effective radical scavengers (Sci. Rev. 2 (1997) 152; J. Nat. Prod. Rev. 63 (2000) 1035). In this manuscript we describe the antioxidant activity of new thioureidic compounds.

Introduction

Several studies have investigated the in vitro biological activity of synthetic thioureidic derivatives and have established important structure–activity relationships. Thus, we have investigated the free-radical scavenging and antioxidant effectiveness of synthetic thioureidic derivatives, which demonstrated antiamebic activity, by using different in vitro methods:

  • 1

    in aqueous phase, detection of the relative antioxidant capability to scavenge the chromogenic radical cation 2,2′-azinobis(3-ethyl-benzothiazoline-6-sulfonate (ABTS+radical dot) in comparison with Trolox and expressed as TEAC [1], [2]. ABTS+radical dot, cation radical, is a blue–green cromogen with a characteristic absorption at 734 nm. The antioxidant activities of compounds are expressed as TEAC, trolox equivalent antioxidant capacity;

  • 2

    heat-induced oxidation of an acqueous emulsion system of β-carotene and linoleic acid was measured by the method described by Pratt (1992) [3];

  • 3

    superoxide anion enzymatic generation assay. Superoxide anion was generated in an enzymatic system by preparing a mixture of xanthine and xanthine oxidase [4];

  • 4

    xanthine oxidation inhibition assay; in this assay xanthine oxidase activity was evaluated by the spectrophotometric measurement of the formation of uric acid by xanthine [4].

Section snippets

Chemicals

ABTS (2,2′-azinobis-3-ethilbenzothiazoline-6 sulfonic acid), Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), potassium persulfate, linoleic acid, Tween 20, butylhydroxytoluene, β-carotene, EDTA, bovine serum albumin (BSA), nitroblue–tetrazolium (NBT), xanthine, xanthine oxidase (XOD), sodium carbonate, sodium phosphate monobasic and sodium phosphate dibasic were obtained by Sigma Aldrich (Gillingham, Dorset, UK). The solvents were obtained by Carlo Erba reagent. Nanopure water

Free Radical scavenging assay

Trolox (a water soluble vitamin E analogue) equivalent antioxidant capacity (TEAC) has been used to determine the radical scavenging abilities of synthetic thioureidic derivatives as electron or Hradical dot donating agents throughout their ability to scavenge ABTS+radical dot The TEAC value resulting for compounds 16 are summarized in Table 1.

Linoleic acid autoxidation assay

The antioxidant effect of synthetic thioureidic derivatives was also measured by autoxidation of β-carotene assay. The value of antioxidant activity (AA) measured a t=60 and

Discussion

A fascinating hypothesis raised in the past few years is that the health-promoting action of some foods could be due to the presence of nonessential components, such as polyphenols (many with antioxidant potential) that could contribute to the modulation of the oxidative balance in vivo

On the other hand reactive oxygen species (ROS) are considered related to many diseases, including atherosclerosis, liver injury, aging, inflammation, neurovegetative diseases, and cancer.

The present study deals

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