Antioxidant potential of curcumin-related compounds studied by chemiluminescence kinetics, chain-breaking efficiencies, scavenging activity (ORAC) and DFT calculations

• Adriana K. Slavova-Kazakova,
• Silvia E. Angelova,
• Timur L. Veprintsev,
• Petko Denev,
• Davide Fabbri,
• Maria Antonietta Dettori,
• Maria Kratchanova,
• Vladimir V. Naumov,
• Aleksei V. Trofimov,
• Rostislav F. Vasil’ev,
• Giovanna Delogu and
• Vessela D. Kancheva

Beilstein J. Org. Chem. 2015, 11, 1398–1411, doi:10.3762/bjoc.11.151

• Physics and Technology, 9 Institutskiy per., Dolgoprudny, Moscow Region, 141700, Russian Federation 10.3762/bjoc.11.151 Abstract This study compares the ability to scavenge different peroxyl radicals and to act as chain-breaking antioxidants of monomers related to curcumin (1): dehydrozingerone (2

• reactions of the antioxidants with peroxyl radicals; model 2 – lipid autoxidation (lipidAO) used for assessing the chain-breaking antioxidant efficiency and reactivity; model 3 – oxygen radical absorbance capacity (ORAC), which yields the activity against peroxyl radicals generated by an azoinitiator; model

• natural ones as potential pharmaceutical and food ingredients. The present study compares the capacity of curcumin-related compounds to scavenge different free radicals and to act as chain-breaking antioxidants. Curcumin is one of the best natural antioxidants with a wide spectrum of biological activities

Reactions of nitroxides 15. Cinnamates bearing a nitroxyl moiety synthesized using a Mizoroki–Heck cross-coupling reaction

• Jerzy Zakrzewski and
• Bogumiła Huras

Beilstein J. Org. Chem. 2015, 11, 1155–1162, doi:10.3762/bjoc.11.130

• ][6], simple cinnamic acid derivatives (esters, amides, etc.), and prenylated cinnamates [4], have been proved to be effective as antioxidants [2][7], radical scavengers [2], antimicrobials [2][7][8], antibacterials [2], antivirals [2][7], and fungicides [2][7][8]. Cinnamic derivatives have also been

Encapsulation of biocides by cyclodextrins: toward synergistic effects against pathogens

• Véronique Nardello-Rataj and
• Loïc Leclercq

Beilstein J. Org. Chem. 2014, 10, 2603–2622, doi:10.3762/bjoc.10.273

• aggregation [15]. It is worth mentioning that the additives may also have an effect on the biocidal activity (pH, surfactants, antioxidants, chelating agents, etc.) [16][17]. Moreover, some formulations contain mixtures of biocides in order to obtain additive or synergistic effects [18][19][20][21]. iii

Oxidative phenylamination of 5-substituted 1-hydroxynaphthalenes to N-phenyl-1,4-naphthoquinone monoimines by air and light “on water”

• Julio Benites,
• Juan Meléndez,
• Cynthia Estela,
• David Ríos,
• Luis Espinoza,
• Iván Brito and
• Jaime A. Valderrama

Beilstein J. Org. Chem. 2014, 10, 2448–2452, doi:10.3762/bjoc.10.255

• of their properties as dyes for optical devices [15], antioxidants [16], anticancer agents [17] and precursors of liquid crystalline materials [18]. With regard to the synthesis of N-phenyl-1,4-naphthoquinone monoimines, Bukhtoyarova et al. [19], has described their preparation by reaction of 1,5-DHN

Continuous flow nitration in miniaturized devices

• Amol A. Kulkarni

Beilstein J. Org. Chem. 2014, 10, 405–424, doi:10.3762/bjoc.10.38

• , pharmaceuticals, fuel additives, antioxidants, and rubber accelerators. In the leather industry m-nitrophenol is used as a fungicide and p-nitrophenol as a chemical intermediate for leather preservatives. 2,4-Dinitrophenol is useful for the manufacturing of photographic developers and serves as a wood

Synthesis and biological activity of N-substituted-tetrahydro-γ-carbolines containing peptide residues

• Nadezhda V. Sokolova,
• Valentine G. Nenajdenko,
• Vladimir B. Sokolov,
• Daria V. Vinogradova,
• Elena F. Shevtsova,
• Ludmila G. Dubova and
• Sergey O. Bachurin

Beilstein J. Org. Chem. 2014, 10, 155–162, doi:10.3762/bjoc.10.13

• derivatives, has been found to stabilize and improve mitochondrial functions in different in vivo and in vitro models [8][9] (Figure 1). Another promising class of neuroprotectors are cell-permeable mitochondria-targeting synthetic small peptides, for example, the SS (Szeto–Schiller) peptide antioxidants [10

3-Pyridinols and 5-pyrimidinols: Tailor-made for use in synergistic radical-trapping co-antioxidant systems

• Luca Valgimigli,
• Daniele Bartolomei,
• Riccardo Amorati,
• Evan Haidasz,
• Jason J. Hanthorn,
• Susheel J. Nara,
• Johan Brinkhorst and
• Derek A. Pratt

Beilstein J. Org. Chem. 2013, 9, 2781–2792, doi:10.3762/bjoc.9.313

• Pvt., Ottawa, Ontario, Canada K1N 6N5 10.3762/bjoc.9.313 Abstract The incorporation of nitrogen atoms into the aromatic ring of phenolic compounds has enabled the development of some of the most potent radical-trapping antioxidants ever reported. These compounds, 3-pyridinols and 5-pyrimidinols, have

• stronger O–H bonds than equivalently substituted phenols, but possess similar reactivities toward autoxidation chain-carrying peroxyl radicals. These attributes suggest that 3-pyridinols and 5-pyrimidinols will be particularly effectiveco-antioxidants when used in combination with more common, but less

• reactive, phenolic antioxidants such as 2,6-di-tert-butyl-4-methylphenol (BHT), which we demonstrate herein. The antioxidants function in a synergistic manner to inhibit autoxidation; taking advantage of the higher reactivity of the 3-pyridinols/5-pyrimidinols to trap peroxyl radicals and using the less

Tricyclic flavonoids with 1,3-dithiolium substructure

• Lucian G. Bahrin,
• Peter G. Jones and
• Henning Hopf

Beilstein J. Org. Chem. 2012, 8, 1999–2003, doi:10.3762/bjoc.8.226

• ; dithiolium salts; flavonoids; Introduction The great diversity in physical, chemical and biochemical properties of flavonoids gives them the ability to influence the biological activity of plants, microbes and animals [1][2][3]. Flavonoids are known to be good antioxidants and this is believed to be the

Bioactive selaginellins from Selaginella tamariscina (Beauv.) Spring

• Chao Yang,
• Yutian Shao,
• Kang Li and
• Wujiong Xia

Beilstein J. Org. Chem. 2012, 8, 1884–1889, doi:10.3762/bjoc.8.217

• diseases. The role of free radicals in ageing, in cancer, and in cardiovascular, neurodegenerative and other diseases is more and more widely accepted [21][22]. Antioxidants are attracting increasing scientific and clinical attention. Natural phenolic compounds (flavonoids, lignans, phenolic acids

• , tocopherols, polyphenols and tannins) are the main class of antioxidants and are known to reduce the rate of oxidation by H-transfer (from their phenol groups) to the radicals [23]. There are multiple phenol groups on the large conjugated aromatic skeleton of selaginallins, and this potential antioxidant

Cyclization of ortho-hydroxycinnamates to coumarins under mild conditions: A nucleophilic organocatalysis approach

• Florian Boeck,
• Max Blazejak,
• Markus R. Anneser and
• Lukas Hintermann

Beilstein J. Org. Chem. 2012, 8, 1630–1636, doi:10.3762/bjoc.8.186

• anticoagulants, antifungal agents, antioxidants, or as anthelmintic, hypnotic and cytotoxic agents [1][2][3][4]. Due to their fluorescent properties, coumarins are also widely used as agrochemicals, additives in cosmetics and food, optical brighteners, and dispersed fluorescent and tunable laser-dye optical

An expedient synthesis of 5-n-alkylresorcinols and novel 5-n-alkylresorcinol haptens

• Kirsti Parikka and
• Kristiina Wähälä

Beilstein J. Org. Chem. 2009, 5, No. 22, doi:10.3762/bjoc.5.22

• , Anacardiaceae, Proteaceae) and in some families of bacteria [1]. We have recently shown that 5-n-alkylresorcinols (AR, 1, see Figure 1) act as antioxidants protecting LDL from oxidative damage in in vitro experiments using synthesized pure analogues with varying chain lengths [2]. In addition, AR have various