Structure-antioxidant activity relationship

Natella, R, Nardini, M., Di Filici, M., and Caccini, C., Benzoic and cinnamic acid derivatives as antioxidants Structure-activity relationship, Biosci. Biotechnol. Biochem., 56, 324-325, 1999. 

CAO G, SOFIC E and prior r l (1997) Antioxidant and prooxidant behavior of flavonoids structure-activity relationships . Free Rad Biol Med, 22 (5), 749-60. 

Heim, K.E. et al., Flavonoid antioxidants chemistry, metabolism and structure-activity relationships, J. Nutr. Biochem., 13, 572, 2002. 

Salvi, A. et al., Protein protection by antioxidants development of a convenient assay and structure-activity relationships of natural polyphenols, Helv. Chim. Acta, 85, 867, 2002. 

Heim K, Tagliaferro A, Bobilya D. 2002. Flavonoid antioxidants Chemistry, metabolism and structure-activity relationships. J Nutr Biochem 13 572-584. 

Arora A, Nair MG, Strasburg GM. 1998. Structure-activity relationships for antioxidant activities of a series of flavonoids in a liposomal system. Free Radic Biol Med 24 1355-1363. 

Murias M, Jager W, Handler N, Erker T, Horvath Z, Szekeres T, Nohl H, Gille L. 2005. Antioxidant, prooxidant and cytotoxic activity of hydroxylated resveratrol analogues Structure-activity relationship, Biochem Pharmacol 69 903-912. 

Depending on the analyses of structure-activity relationships and electrochemical studies [158,162], the indole nucleus is the reactive center of interaction with oxidants due to its high resonance stability and very low activation energy wall towards the free-radical reactions. However, the methoxy and amide side chains are also important for indole s antioxidant capacity [169]. 

The modification of these natural polyhydroxylated compounds via acylation of the hydroxyl functions with aliphatic molecules not only increases their structural diversity, producing analogs that may be useful models for the study of structure-activity relationships, but also changes their physicochemical properties, increasing their solubility in lipophilic media. Moreover, the selective acylation of these natural compounds with various acyl donors could enhance their biological activities, such as their antioxidant and antimicrobial activity, as well as their pharmacological properties [5, 6]. 

Vivas et al. 1997). Recently, the evaluation of the dual antioxidant and antibacterial activity of 21 phenolic compounds mainly present in Vitis Vinifera L. belonging to different groups was examined (Garcfa-Ruiz et al. 2008b). Structure-activity relationships were probed for both antimicrobial and antioxidant properties of wine phenolics, confirming the potential of these compounds as an alternative to sulphites in winemaking. 

Bors W, Michel C, Stettmaier K. (2001) Structure-activity relationships governing antioxidant capacities of plant polyphenols. Methods in Enzym 335 166-180. 

Sergediene, E. Jonsson, K. Szymusiak, H. Tyrakowska, B. Rietjens, I.M.C.M. Cenas, N. Prooxidant toxicity of polyphenolic antioxidants to HL-60 cells description of quantitative structure-activity relationships. FEBS Lett. 1999, 462, 392-396. 

Cheng Z, Ren J, Li Y, et al. Establishment of a quantitative structure-activity relationship model for evaluating and predicting the protective potentials of phenolic antioxidants on lipid peroxidation. ] Pharm Sci 2003 92(3) 475-484. 

The inhibition of arachidonic acid metabolism by diarylheptanoids can be attributed to their antioxidant properties. Studies on structure-activity relationships demonstrated that hydroxyl groups were responsible for the antioxidant activity, while an unsubstituted phenyl... 

Very recently a family of diphenyltin(IV) compounds was tested in vitro against human tumor cell lines to assess their cytotoxic activity, and the same family of compounds was also tested for antioxidant efficiency in rat brain homogenate, showing that there is a structure-activity relationship in the latter case. The correlation suggests that selected molecular variables are prototype tracers for the calculation of inhibitory concentrations. Moreover there seems to be an inverse structure-response behavior among activities, since the most hydrophobic organotin molecule is the least active compound for cytotoxic assays, while it is the best in anti-oxidant tests. 

Rasulev, B.F., Abdullaev, N.D., Syrov, V.N. and Leszczynski, J. (2005) A quantitative structure-activity relationship (QSAR) study of the antioxidant activity of fiavonoids. QSAR Comb. Sci., 24, 1056-1065. 

A series of 2-substituted 3-chloro-1,4-naphthoquinones were synthesized and their anti-inflammatory activities were evaluated. The structure-activity relationships in this series were also examined. Most of the 2-alkyl/arylcarboxamido derivatives of 3-chloro-l,4-naphthoquinones showed potent activity [122,123], Selected naphthoquinone compounds were investigated for 5-lipoxygenase inhibiting and antioxidative properties. There is a clear-cut correlation of both qualities in those compounds with a 3-hydroxy function and with two, one or without any tert-butyl group at the phenyl moiety [124],... 

The pharmacological assays and activities of natural phenylpropanoid glycosides, extracted from a variety of plants are summarized in this review, such as antioxidant, anti-inflammatory, healing, antimicrobial and antitumoral-chemopreventive. Structure-activity relationships are also discussed. 

Even so, it has been concluded that there is a structure-activity relationship between the different PPGs. There is a direct relationship between the antioxidant activity and the number of hydroxyl groups, and an inverse relationship with the increasing of higher monosaccharides moieties. 

There have not been many reports on the structure-activity relationship (SAR) studies on the bioactive compounds from Hedyotis. However, some SAR studies on the antioxidant and the neuroprotective constituents from H. diffusa have been reported recently. We include in this review some of our observations on the SAR studies of some active flavonoids. 

STRUCTURE-ACTIVITY RELATIONSHIP OF FLAVONOIDS AS ANTIOXIDANT AND PRO-OXIDANT... 

These results are in agreement with the structure-activity relationship proposed by Bors et al., who used pulse radiolysis to study the antioxidant activity of flavonoids [116-118]. 

The initial selection of adjuvants to crinitol was based largely on the above mentioned structure-activity relationship study. Thus, the hydroxy group at C-9 in crinitol seems to be essential to its antibacterial activity. The allylic C-9 hydroxy group is easily oxidized, a possibility which might detoxify crinitol in bacterial systems. Because crinitol possesses two allylic alcohol groups in its molecule (at C-1 and C-9), we combined it with several antioxidants which have been used as food and cosmetic additives. Thus two natural antioxidants, vitamins C and E, and two synthetic antioxidants, BHA and BHT, were chosen for the experiment. While the synthetic antioxidants exhibited antimicrobial activity against all the test bacteria (30), natural antioxidants did not show any activity up to 800... 

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