Biomimetic synthesis and HPLC–ECD analysis of the isomers of dracocephins A and B

• Viktor Ilkei,
• András Spaits,
• Anita Prechl,
• Áron Szigetvári,
• Zoltán Béni,
• Miklós Dékány,
• Csaba Szántay Jr,
• Judit Müller,
• Árpád Könczöl,
• Ádám Szappanos,
• Attila Mándi,
• Sándor Antus,
• Ana Martins,
• Attila Hunyadi,
• György Tibor Balogh,
• György Kalaus (†),
• Hedvig Bölcskei,
• László Hazai and
• Tibor Kurtán

Beilstein J. Org. Chem. 2016, 12, 2523–2534, doi:10.3762/bjoc.12.247

• increase P-gp inhibitory activity [18]. Based on the unaltered accumulation of rhodamine 123, a P-gp substrate fluorescent dye, in the P-gp transfected L5178MDR cells, we observed that none of the synthesized compounds inhibits this transporter. The antioxidant activity of dracocephins A and B was also

Tunable microwave-assisted method for the solvent-free and catalyst-free peracetylation of natural products

• Manuela Oliverio,
• Paola Costanzo,
• Monica Nardi,
• Carla Calandruccio,
• Raffaele Salerno and
• Antonio Procopio

Beilstein J. Org. Chem. 2016, 12, 2222–2233, doi:10.3762/bjoc.12.214

• ester (8), uridine (12) and methyl-α-D-glucopyranoside (11)) and natural antioxidant compounds in their simple (hydroxytyrosol (4), homovanillic alcohol (5), quercetin (13)) or glycosylated forms (oleuropein (14), rutin (17), alpha-hederin (16)). Because of their heterogeneity in terms of

New furoisocoumarins and isocoumarins from the mangrove endophytic fungus Aspergillus sp. 085242

• Ze’en Xiao,
• Senhua Chen,
• Runlin Cai,
• Shao’e Lin,
• Kui Hong and
• Zhigang She

Beilstein J. Org. Chem. 2016, 12, 2077–2085, doi:10.3762/bjoc.12.196

• 180 μL of DPPH· was recorded as ADPPH·, and the absorbance of the 200 μL of MeOH was measured as Ablank. The natural antioxidant vitamin C was used as a positive control. Calculations of the DPPH· scavenging activity was performed according to the following equation: scavenging activity (%) = [1

Three new trixane glycosides obtained from the leaves of Jungia sellowii Less. using centrifugal partition chromatography

• Luíse Azevedo,
• Larissa Faqueti,
• Marina Kritsanida,
• Antonia Efstathiou,
• Despina Smirlis,
• Gilberto C. Franchi Jr,
• Grégory Genta-Jouve,
• Sylvie Michel,
• Louis P. Sandjo,
• Raphaël Grougnet and
• Maique W. Biavatti

Beilstein J. Org. Chem. 2016, 12, 674–683, doi:10.3762/bjoc.12.68

• -inflammatory and antioxidant effects of J. paniculata were associated to the presence of flavonoids and other polyphenols [4]. Recently, we reported the in vivo anti-inflammatory properties of an aqueous fraction of the leaves of J. sellowii, that is in agreement with its popular use in Brazil [5]. Apart from

Biosynthesis of α-pyrones

• Till F. Schäberle

Beilstein J. Org. Chem. 2016, 12, 571–588, doi:10.3762/bjoc.12.56

• chestnut) showed antioxidant activity [28]. Testing urolithins A, B, C, D (23–26) in an assay using myelomonocytic HL-60 cells showed antioxidant activities for 23, 25 and 26. These three derivatives inhibited the reactive oxygen species (ROS)-dependent oxygenation of the non-fluorescent 2’,7

• ’-dichlorodihydrofluorescein (DCFH) to the fluorescent 2’,7’-dichlorofluorescein (DCF) [29]. This antioxidant activity was also linked to anti-inflammatory effects by testing the in vivo effects of 23 in a carrageenan-induced paw edema assay. Oral administration of 23 to mice prior to carrageenan injection resulted in a

A selective and mild glycosylation method of natural phenolic alcohols

• Mária Mastihubová and
• Monika Poláková

Beilstein J. Org. Chem. 2016, 12, 524–530, doi:10.3762/bjoc.12.51

• phenylpropenyl) glycosides having a free phenolic function at the para-position of the aglycone are substances widely occurring in plants. They exhibit numerous biological activities which are in many cases related to their structure–antioxidant activity relationship. 4-Hydroxy-3-methoxybenzyl β-D

Thermal and oxidative stability of Atlantic salmon oil (Salmo salar L.) and complexation with β-cyclodextrin

• Daniel I. Hădărugă,
• Mustafa Ünlüsayin,
• Alexandra T. Gruia,
• Cristina Birău (Mitroi),
• Gerlinde Rusu and
• Nicoleta G. Hădărugă

Beilstein J. Org. Chem. 2016, 12, 179–191, doi:10.3762/bjoc.12.20

• natural antioxidants are flavonoids, anthocyanins and their glycosides. Huber and collaborators [18] revealed the inhibition of PUFA oxidation by quercetin and its 3-O-glucoside. They were as effective as butylated hydroxytoluene (BHT, a synthetic antioxidant) against the oxidation of DHA and methylated

• during the process of fish oil production leads to improved stability up to 400% [22]. Smoking the pink salmon before the oil extraction process was another method for reducing the oxidation by forming phenolic antioxidant compounds [23][24]. Another way to stabilize fish oil is microencapsulation using

Determination of formation constants and structural characterization of cyclodextrin inclusion complexes with two phenolic isomers: carvacrol and thymol

• Miriana Kfoury,
• David Landy,
• Steven Ruellan,
• Lizette Auezova,
• Hélène Greige-Gerges and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2016, 12, 29–42, doi:10.3762/bjoc.12.5

• Environnementale et Interactions sur le Vivant (UCEIV, EA 4492), ULCO, F-59140 Dunkerque, France 10.3762/bjoc.12.5 Abstract Carvacrol and thymol have been widely studied for their ability to control food spoilage and to extend shelf-life of food products due to their antimicrobial and antioxidant activities

• increasing the shelf-life of food products [7][8]. This is due to their potent activity against a broad range of natural spoilage bacteria, fungi and foodborne pathogens [9][10] as well as their pronounced antioxidant effect [11][12]. Consequently, they could be employed as alternatives to synthetic

• most energetically favorable conformation of inclusion complexes. Finally, the effect of encapsulation on the antioxidant properties of 1 and 2 was evaluated using the ABTS radical cation assay. Results and Discussion UV–visible competitive studies Stoichiometries and Kf values of inclusion complexes

Inclusion complexes of 2-methoxyestradiol with dimethylated and permethylated β-cyclodextrins: models for cyclodextrin–steroid interaction

• Mino R. Caira,
• Susan A. Bourne,
• Halima Samsodien and
• Vincent J. Smith

Beilstein J. Org. Chem. 2015, 11, 2616–2630, doi:10.3762/bjoc.11.281

• and especially in the case of TRIMEB [30]. The TRIMEB·2ME complex is thus another example of a synthetic system that displays host–guest adaptation on complexation, complementing our recently reported analogous observations for inclusion complexes between methylated CDs and the antioxidant trans

Cross-metathesis of polynorbornene with polyoctenamer: a kinetic study

• Yulia I. Denisova,
• Maria L. Gringolts,
• Alexander S. Peregudov,
• Liya B. Krentsel,
• Ekaterina A. Litmanovich,
• Arkadiy D. Litmanovich,
• Eugene Sh. Finkelshtein and
• Yaroslav V. Kudryavtsev

Beilstein J. Org. Chem. 2015, 11, 1796–1808, doi:10.3762/bjoc.11.195

• magnetic stirrer under inert atmosphere at 20 °C. The polymerization was stopped by the addition of 0.3 mL of ethyl vinyl ether after 2 h. The polymers were precipitated in a 0.1% acetone solution of an antioxidant 2,2’-methylenebis(6-tert-butyl-4-methylphenol) (1), decanted, washed with several portions

• of the same solution, and dried under reduced pressure at room temperature until constant mass. The yield was 2.72 g (76%). Polymer (1 g) was dissolved in 0.4% THF solution of HCl (30 mL), stirred for 4 h and precipitated in a 0.1% ethanol solution of an antioxidant 1, decanted, washed with several

• ) solution in toluene (12.3 mL) prepared as described above at 20 °C. The polymerization was stopped by the addition of 0.4 mL of ethyl vinyl ether after 1 h. The polymers were precipitated in a 0.1% ethanol solution of antioxidant 1, decanted, washed with several portions of the same solution, and dried

Pyridinoacridine alkaloids of marine origin: NMR and MS spectral data, synthesis, biosynthesis and biological activity

• Louis P. Sandjo,
• Victor Kuete and
• Maique W. Biavatti

Beilstein J. Org. Chem. 2015, 11, 1667–1699, doi:10.3762/bjoc.11.183

• , terpenoids, phenolics, polysaccharides and alkaloids [4]. Various bioactivity functions such as anticancer [5][6][7], phytotoxicity [8][9][10][11], antioxidant [12][13][14][15][16], antimicrobial [17][18][19], analgesic [20][21], hypotensive [22], hypoglycemic [23], antiprotozoal [24] and plant protecting

Dicarboxylic esters: Useful tools for the biocatalyzed synthesis of hybrid compounds and polymers

• Ivan Bassanini,
• Karl Hult and
• Sergio Riva

Beilstein J. Org. Chem. 2015, 11, 1583–1595, doi:10.3762/bjoc.11.174

• fungal β-N-acetylhexosaminidase evaluated [28]. Similarly, dimers of sylibin (11a,b, Figure 3) and dehydrosylibin, obtained by Novozyme 435-catalyzed acylation with the divinyl esters of dodecanedioc acid, were evaluated in terms of antioxidant activity and cytotoxicity [29]. The obvious hypothesis

• based on the conjugation of an acylated sylibin derivative (19) with L-ascorbic acid (20), tyrosol (21) and trolox alcohol (22) (Scheme 4) [44]. These compounds proved to have excellent electron donor, antiradical, antioxidant as well as cytoprotective abilities. Moreover, in a different research area

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

• 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

• 4 – density functional theory (DFT) calculations at UB3LYP/6-31+G(d,p) level, applied to explain the structure–activity relationship. Dimers showed 2–2.5-fold higher values of kA than their monomers. Model 2 gives information about the effects of the side chains and revealed much higher antioxidant

• activity for monomers and dimers with α,β-unsaturated side chains. Curcumin and 6 in fact are dimers of the same monomer 2. We conclude that the type of linkage between the two “halves” by which the molecule is made up does not exert influence on the antioxidant efficiency and reactivity of these two

New depsidones and isoindolinones from the mangrove endophytic fungus Meyerozyma guilliermondii (HZ-Y₂) isolated from the South China Sea

• Senhua Chen,
• Zhaoming Liu,
• Yayue Liu,
• Yongjun Lu,
• Lei He and
• Zhigang She

Beilstein J. Org. Chem. 2015, 11, 1187–1193, doi:10.3762/bjoc.11.133

• of bioactivities including antibacterial [10], antifungal [6], antiviral [12], antioxidant [5], and cytotoxic [9]. In the last decade, our research group has been focused on isolating novel compounds from endophytic fungi growing on mangroves in the South China Sea and investigating their bioactivity

The reactions of 2-ethoxymethylidene-3-oxo esters and their analogues with 5-aminotetrazole as a way to novel azaheterocycles

• Marina V. Goryaeva,
• Yanina V. Burgart,
• Marina A. Ezhikova,
• Mikhail I. Kodess and
• Viktor I. Saloutin

Beilstein J. Org. Chem. 2015, 11, 385–391, doi:10.3762/bjoc.11.44

• ], antiviral [14], antimicrobial and antioxidant activity [15] have been found among them. The known tetrazolo[1,5-a]pyrimidines were synthesized by cyclocondensation of 5-AT with 1,3-dicarbonyl compounds or their derivatives [16]. Moreover, a convenient method for obtaining this heterocyclic skeleton is the

Natural phenolic metabolites with anti-angiogenic properties – a review from the chemical point of view

• Qiu Sun,
• Jörg Heilmann and
• Burkhard König

Beilstein J. Org. Chem. 2015, 11, 249–264, doi:10.3762/bjoc.11.28

• than curcumin. To date, the number of synthesized single enones and MACs have surpassed the 1000 mark. Ellagic acid Ellagic acid (7) is a naturally existing phenolic antioxidant widely found in numerous fruits and vegetables, such as raspberries (Rubus idaeus L., Rosaceae), strawberries (Fragaria spec

• . L., Rosaceae) and pomegranates (Punica granatum L., Lythraceae). It shows potent antioxidant effects by radical scavenging and the inhibition of lipid peroxidation [28][29]. Ellagic acid is also capable of interfering with some angiogenesis-dependent pathways. It exhibits anticarcinogenic activity

• . Resveratrol Resveratrol (8) is a natural polyphenol that belongs to the stilbene-type compounds and exists in a large number of plants. It has been primarily extracted from grape (Vitis vinifera L., Vitaceae) and mulberry (Morus L., Moraceae) fruits (Figure 4) [34]. It has antioxidant effects, anti-estrogenic

Cathodic reductive coupling of methyl cinnamate on boron-doped diamond electrodes and synthesis of new neolignan-type products

• Taiki Kojima,
• Rika Obata,
• Tsuyoshi Saito,
• Yasuaki Einaga and
• Shigeru Nishiyama

Beilstein J. Org. Chem. 2015, 11, 200–203, doi:10.3762/bjoc.11.21

• interesting biological activities [1]. Due to their plausible roles as defense substances of plants, lignans, neolignans, and their congeners are promising candidates for agricultural chemicals, and some of their antioxidant and/or anti-inflammatory properties may be utilized for biological research and as

Inclusion of trans-resveratrol in methylated cyclodextrins: synthesis and solid-state structures

• Lee Trollope,
• Dyanne L. Cruickshank,
• Terence Noonan,
• Susan A. Bourne,
• Milena Sorrenti,
• Laura Catenacci and
• Mino R. Caira

Beilstein J. Org. Chem. 2014, 10, 3136–3151, doi:10.3762/bjoc.10.331

• Taramelli 12, 27100 Pavia, Italy 10.3762/bjoc.10.331 Abstract The phytoalexin trans-resveratrol, 5-[(1E)-2-(4-hydroxyphenyl)ethenyl]-1,3-benzenediol, is a well-known, potent antioxidant having a variety of possible biomedical applications. However, its adverse physicochemical properties (low stability

• -resveratrol (5-[(1E)-2-(4-hydroxyphenyl)ethenyl]-1,3-benzenediol; trans-3,5,4′-trihydroxystilbene, RSV) (1, Figure 1), is a triphenolic species which is known to have potent antioxidant activity and consequently a wide range of pharmacological activities [1][2]. In recent years the list of potential medicinal

• inclusion compounds as single crystals enabled their complete structural elucidation, revealing several novel supramolecular features which are relevant for future studies of the antioxidant RSV. Availability of well-defined, crystalline inclusion complexes also ensured that their characterization using

Binding mode and free energy prediction of fisetin/β-cyclodextrin inclusion complexes

• Bodee Nutho,
• Wasinee Khuntawee,
• Chompoonut Rungnim,
• Piamsook Pongsawasdi,
• Peter Wolschann,
• Alfred Karpfen,
• Nawee Kungwan and
• Thanyada Rungrotmongkol

Beilstein J. Org. Chem. 2014, 10, 2789–2799, doi:10.3762/bjoc.10.296

• strawberries, grapes, apples, lotus roots, cucumbers and onions [6]. Fisetin has many interesting biological activities and particularly pharmacological properties, including antioxidant, anti-inflammatory, anticarcinogenic and antiviral activities [7]. It was found that fisetin can prevent oxidation which may

• understand the two flavonoids/β-CD complexes, hesperetin and naringenin complexes, in aqueous solution. The PM3 method was applied to calculate the energy regarding the antioxidant property of the flavonoid chysin in the complex with β-CD [32]. Interestingly, the molecular docking study on the fisetin/β-CD

Aspergiloid I, an unprecedented spirolactone norditerpenoid from the plant-derived endophytic fungus Aspergillus sp. YXf3

• Zhi Kai Guo,
• Rong Wang,
• Wei Huang,
• Xiao Nian Li,
• Rong Jiang,
• Ren Xiang Tan and
• Hui Ming Ge

Beilstein J. Org. Chem. 2014, 10, 2677–2682, doi:10.3762/bjoc.10.282

• graminearum Schw., Fusarium coeruleum Sacc., Botrytis cinerea Pers., and Fusarium oxysporum f. sp. cubense race 4), and Candida albicans (ATCC 10231), and the antioxidant, acetylcholinesterase (AChE) , α-glucosidase, and topoisomerase IIα inhibitory activities were performed in accordance with the primary

Superoxide chemistry revisited: synthesis of tetrachloro-substituted methylenenortricyclenes

• Basavaraj M. Budanur and
• Faiz Ahmed Khan

Beilstein J. Org. Chem. 2014, 10, 2531–2538, doi:10.3762/bjoc.10.264

• of the superoxide ion leading to the synthesis of tetrachloroaryl/vinyl-substituted nortricyclenes through its dual mode of action has been reported. KO2 was found to be superior and the only reagent to perform this kind of reaction over other conventional bases. Addition of the antioxidant BHT (2,6

• the mechanistic aspects of the reaction we have treated 3f/4f under standard conditions by using the additive radical quencher and antioxidant BHT (5 mol %) afforded the product 5f in improved yield of 94% (Scheme 3). Similarly, substrates 3c/4c and 3i/4i afforded 5c and 5i in 91% and 89% yield

Effect of cyclodextrin complexation on phenylpropanoids’ solubility and antioxidant activity

• Miriana Kfoury,
• David Landy,
• Lizette Auezova,
• Hélène Greige-Gerges and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2014, 10, 2322–2331, doi:10.3762/bjoc.10.241

• ) and the solubilizing potential of CD was proposed. Molecular modeling was used to investigate the complementarities between host and guest. Finally, the antioxidant activity of encapsulated PPs was evaluated by scavenging of the stable DPPH radical. Keywords: antioxidant activity; complexation

• antioxidant activity and therefore are considered to have beneficial effects on human health [3][4]. PPs are also known to have antibacterial, antifungal and anti-inflammatory properties [5][6][7]. However, they have restricted applications as pharmaceutical products and food preservatives because they have

• presented in Figure 5. Isoeugenol (3), eugenol (4), p-coumaric acid (5), caffeic acid (6) and ferulic acid (7) presented higher antioxidant activity than trans-anethole (1) and estragole (2). It is well known that the antioxidant activity of phenolic compounds such as PPs depends mainly on the degree of

Synthesis of 2-substituted tryptophans via a C3- to C2-alkyl migration

• Michele Mari,
• Simone Lucarini,
• Francesca Bartoccini,
• Giovanni Piersanti and
• Gilberto Spadoni

Beilstein J. Org. Chem. 2014, 10, 1991–1998, doi:10.3762/bjoc.10.207

• these compounds is of particular interest as 2-prenyltryptophan derivatives have been obtained or isolated from a diverse array of natural sources [66][67] and, in general, prenylation at the indole ring leads to a significant increase in the antioxidant and/or cytotoxic activity of tryptophan

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

• revealed an antioxidant and mitoprotective potential of the new synthesized peptide-modified N-substituted tetrahydro-γ-carbolines. Further investigations of this class of compounds may allow finding a promising approach to cytoprotection, in particularly, neuroprotection. Conclusion In summary, we

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

• revision of the H-bonding basicity value of acetonitrile to β2H of 0.39. Overall, the thermodynamic and kinetic data presented here enable the design of co-antioxidant systems comprising lower loadings of the more expensive 3-pyridinol/5-pyrimidinol antioxidants and higher loadings of the less expensive

• resultant phenoxyl radical (ArO•) is sufficiently unreactive toward the substrate (RH) that it reacts with a second peroxyl radical (reaction 2 in Scheme 2), thereby breaking two oxidative chains per molecule of antioxidant – a ratio commonly referred to as the stoichiometric factor (n). However, under some

• circumstances (e.g. when diffusion of the antioxidant is impeded and it has limited opportunity to encounter other radical species), it is possible for the antioxidant-derived phenoxyl radical to propagate the chain reaction (reaction 3 in Scheme 2). The most relevant example of this is so-called ‘tocopherol