Antioxidant and structure–activity relationships (SARs) of some phenolic and anilines compounds

ADVERTISEMENT RETURN TO ISSUEPREVCommentComment on "Temperature and Solvent Effects on Radical Scavenging Ability of Phenols"Grzegorz Litwinienko†§ and Peter Mulder*‡View Author Information Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland, and Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands* To whom correspondence should be addressed. E-mail: [email protected]†University of Warsaw.‡Leiden University.§E-mail: [email protected].Cite this: J. Phys. Chem. A 2009, 113, 50, 14014–14016Publication Date (Web):November 19, 2009Publication History Received7 September 2009Revised22 October 2009Published online19 November 2009Published inissue 17 December 2009https://pubs.acs.org/doi/10.1021/jp908635khttps://doi.org/10.1021/jp908635karticle-commentaryACS PublicationsCopyright © 2009 American Chemical Society. This publication is available under these Terms of Use. Request reuse permissions This publication is free to access through this site. Learn MoreArticle Views691Altmetric-Citations13LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail PDF (92 KB) Get e-AlertscloseSUBJECTS:Aromatic compounds,Hydrocarbons,Hydrogen abstraction,Kinetic parameters,Solvents Get e-Alerts

We investigated the effects of phenolic and phenol compounds on 3,3',5-L-125I-triiodothyronine (125I-T3) binding to purified Xenopus laevis transthyretin (xTTR) and to the ligand-binding domain of X. laevis thyroid hormone receptor beta (xTR LBD), on T3-induced metamorphosis in X. laevis tadpoles and on the induction of T3-dependent reporter gene in a X. laevis cell line. Of the halogenated phenolic and phenol compounds tested, 3,3',5-trichlorobisphenol A and 2,4,6-triiodophenol, respectively, were the most potent competitors of 125I-T3 binding to both xTTR and xTR LBD. Most of the halogenated compounds had stronger interactions with xTTR than with xTR LBD. Generally, chlorinated derivatives with a greater degree of chlorination were more efficient competitors of T3 binding to xTTR and xTR LBD. Structures with a halogen in either ortho position or in both ortho positions, with respect to the hydroxy group, were more efficient competitors. 3,3',5-Trichlorobisphenol A and 2,4,6-triiodophenol acted as T3 antagonists in the X. laevis tadpole metamorphosis assay. Interestingly, o-t-butylphenol and 2-isopropylphenol, for which xTTR and xTR LBD had weak or no significant affinity, showed T3 antagonist activity in the metamorphosis assay. T3 antagonist activities of all these chemicals except for o-t-butylphenol were verified by T3-dependent reporter gene assay. Our results suggest that some phenolic and phenol compounds target the process of T3 binding to xTTR and xTR and/or an unknown process, and that they interfere with the intracellular T3 signaling pathway.

Miscanthus sacchariflorus is a potential source of sustainable biofuel and other bioactive compounds. The high adaptive range of M. sacchariflorus may cause variation in its morphological traits and phytochemical composition. Although some metabolites have been reported from M. sacchariflorus, little is known about its phenolic compound composition and antioxidant or oxidant properties. This study evaluated the morphological traits, antioxidant properties, and phenolic compound profile of M. sacchariflorus collected from various regions of China, Korea, Japan, and Russia. The antioxidant potential of the leaf extracts of various accessions of M. sacchariflorus was estimated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay and 2,2′-azinobis 3-ethylbenzothiazoline-6-sulfonate (ABTS). An extensive study of the antioxidant activity and phenolic compounds of M. sacchariflorus obtained from different locations in four different countries could provide a comprehensive catalogue of the phytoconstituents and antioxidant properties of M. sacchariflorus accessions to consumers and nutraceutical industries. A total of 22 phenolic compounds were identified and quantified, among which p-coumaric acid, ferulic acid, p-hydroxybenzoic acid, chlorogenic acid, vitexin, and luteolin were the most dominant phytochemical compounds detected in the majority of the accessions. The antioxidant potential (DPPH) of the leaf extracts of all of the accessions ranged from 28.85 ± 1.53 µg mL−1 in MS-447 to 99.25 ± 1.63 µg mL−1 in MS-190. The antioxidant properties (ABTS) of the leaf extracts of all accessions ranged from 25.65 ± 2.06 in MS-258 to 83.62 ± 2.02 in MS-271. Pearson’s correlation analysis showed a significant and positive correlation between antioxidant activity and total phenolic content, and total flavonoid content varied widely among M. sacchariflorus accessions from the four geographical study regions. A strong and positive association was observed between DPPH with total phenolic content and total flavonoid content. Moderately positive correlations were observed between DPPH scavenging activity with gentisic acid, p-hydroxybenzoic acid, chlorogenic acid, p-coumaric acid, rutin, and quercetin (r = 0.385, r = 0.379, r = 0.362, r = 0.353, r = 0.490, and r = 0.372, respectively), suggesting that phenolic compounds are major contributors to the antioxidant potential of M. sacchariflorus. Thirty-two accessions collected from four different countries (China, Korea, Japan, and Russia) were characterized for 17 quantitative morphological traits. A wide range of diversity was observed in the morphological traits, with plant height ranging from 18.00 ± 1.00 cm to 163.20 ± 4.00 cm. Plant height was significantly correlated with biomass yield (fresh weight; r = 0.439, p < 0.05) and also had moderately positive correlations with culm length (r = 0.356, p < 0.05). Culm length was moderately correlated with the biomass yield fresh weight (r = 0.419*, p < 0.05) and the biomass yield dry weight (r = 0.425*, p < 0.05); however, it exhibited weak and negative correlations with compressed plant circumference (CCirc) (r = −0.374, p < 0.05) and total culm node number (TCmN) (r = −0.440, p < 0.05). Principal components analysis was performed to assess the variation in 17 morphological traits in 32 accessions of M. sacchariflorus. The first two principal components explained 51.24% of the morphological variations. A dendrogram generated from unweighted pair group method with arithmetic mean (UPGMA) clustering based on morphological characters was not found to be consistent with another dendrogram based on phytochemicals. In both cases, the number of studied accessions collected from different geographical regions grouped into two major groups. However, no clear correlation between these two different approaches was found. The substantial variation in the morphological traits, bioactive properties, and phenolic compounds among the accessions may provide useful information for breeding programs attempting to obtain M. sacchariflorus varieties with improved phenolic compounds traits and improved bioactive properties.

Turnip (Brassica rapa ssp. rapa) is an important vegetable crop producing glucosinolates (GSLs) and phenolic compounds. The GSLs, phenolic compound contents and transcript levels in hairy root cultures, as well as their antioxidant, antimicrobial and anticancer activity were studied in turnip. Transgenic hairy root lines were confirmed by polymerase chain reaction (PCR) and reverse transcription-PCR. GSLs levels (glucoallysin, glucobrassicanapin, gluconasturtiin, glucobrassicin, 4-methoxyglucobrassicin, neoglucobrassicin and 4-hydroxyglucobrassicin) and their gene expression levels (BrMYB28, BrMYB29, BrMYB34, BrMYB51, BrMYB122, CYP79 and CYP83) significantly increased in hairy roots compared with that in non-transformed roots. Furthermore, hairy roots efficiently produced several important individual phenolic compounds (flavonols, hydroxybenzoic and hydroxycinnamic acids). Colorimetric analysis revealed that the highest levels of total phenol, flavonoid contents, and their gene expression levels (PAL, CHI and FLS) in hairy roots than non-transformed roots. Our study provides beneficial information on the molecular and physiological active processes that are associated with the phytochemical content and biosynthetic gene expression in turnip. Moreover, antioxidant activity, as measured by DPPH scavenging activity, reducing potential, phosphomolybdenum and ferrous ion chelating ability assays was significantly higher in hairy roots. Hairy root extracts exhibited higher antimicrobial activity against bacterial and fungal species. The extract of hairy roots showed inhibition of human breast and colon cancer cell lines.

‘珍珠拔’番石榴(Psidium guajava cv. ‘Jenju Bar’)及‘台農二號’番木瓜(Carica papaya cv. ‘Tainong No.2’)為台灣常見具高抗氧化力熱帶水果。本試驗以三價鐵離子還原法測定不同熟度之珍珠拔番石榴及台農二號番木瓜果實之抗氧化力，並分析果肉中維生素C及總酚類含量。 分析相異直徑果實之抗氧化力可得知番石榴果實抗氧化力大致隨著果實增大而下降。不同季節珍珠拔番石榴果實發育所需時間不同，夏季果實由開花至果實成熟約需113天，冬果則需140天。但兩季果實抗氧化力及抗氧化物質變化趨勢相似，果肉抗氧化力及總酚類含量隨果實發育而下降，而維生素C含量於果實接近成熟時有上升之趨勢。成熟夏果之總酚類含量高於冬果，而冬果具有較高之維生素C含量。以單位濃度乘上果實重量可得單一果抗氧化物之總量。珍珠拔果實發育期間，雖然果肉抗氧化力以及抗氧化物質濃度因果實膨大而被稀釋，但單一果實之抗氧化力與抗氧化物總量則隨果實發育持續累積。 番木瓜果實發育期間抗氧化力及抗氧化物之變化趨勢與番石榴相異。台農二號番木瓜冬季果實自花後56天至196天完全黃熟期間，果肉之抗氧化力、維生素C及總酚類含量持續上升，且上升趨勢於果實後熟階段更加顯著。 採收全株由盛花後至20%轉色之不同熟度果實，數據依形成果實之花序順序由上往下換算為十區段，以表現果實生長情形及抗氧化物含量變化趨勢，且利於植株間比較。當果實隨區段數增加漸趨成熟，果肉之抗氧化力及抗氧化物含量呈現先降後升之變化趨勢，顯示發育初期之番木瓜果實之抗氧化力與抗氧化物質含量較接近於成熟果，而高於發育中期之果實。 電石催熟可提昇番木瓜之抗氧化力。催熟兩天再置於25℃環境下三天達到完全後熟之番木瓜果實，果肉之抗氧化力、維生素C及總酚類含量分別為催熟前提昇24%、54%及26%。

Infertility is a global health issue and is closely related to oxidative stress, which occurs when high concentrations of free radicals surpass the protective effects of antioxidant molecules and enzymes. Such imbalance causes damage to DNA, as well as cellular proteins and lipids, ultimately leading to the destruction of the blood-testis barrier. This, in turn, hinders spermatogenesis. Various plants and compounds have been employed in an attempt to reverse these damages, such as phenolic compounds. Therefore, this review aims to identify the main phytochemical phenolic compounds and their respective effects when used in the treatment of male infertility. Related information concerning phenolic phytochemical compounds was gathered from studies selected from PubMed, Scopus, and Web of Science databases. The search was conducted using the combination of six terms: "phenolic compounds", "male infertility", "testis", "spermatozoa", "testosterone" and "male fertility". These compounds can raise testosterone levels, reduce lipid peroxidation, and improve tubular histoarchitecture in cases of subfertility associated with diabetes mellitus. They can also mitigate the damage caused by obesity by increasing serum testosterone, antioxidant activity, and sperm motility. When it comes to fertility problems caused by inorganic and organic pollutants, these compounds effectively restore the structure of the seminiferous tubules, increase testosterone levels, and improve sperm quality. Furthermore, phenolic phytochemical compounds have shown beneficial effects in countering the adverse impacts of certain drugs on testicular physiology by reducing apoptosis in testicular tissue, increasing the number of Leydig cells, and promoting spermatocyte production. However, while these compounds may have protective effects on sperm cryopreservation for in vitro fertilization, caution is needed as certain dosages can cause irreversible damage to sperm quality. Overall, plant extracts containing phenolic phytochemical compounds hold promise as a therapeutic avenue for treating infertility and subfertility caused by metabolic disorders and environmental pollutants.

We investigated the effects of the brominated phenolic and phenol compounds, some of which are brominated flame retardants, on the binding of (125)I-3,3',5-L-triiodothyronine ((125)I-T(3)) to purified Xenopus laevis transthyretin (xTTR) and to the ligand-binding domain of X. laevis thyroid hormone receptor beta (xTR LBD), on the induction of a T(3)-responsive reporter gene in a recombinant X. laevis cell line (XL58-TRE-Luc) and on T(3)-induced or spontaneous metamorphosis in X. laevis tadpoles. Of the brominated phenolic and phenol compounds tested, 3,3',5-tribromobisphenol A and 3,3'-dibromobisphenol A were the most potent competitors of (125)I-T(3) binding to xTTR and the xTR LBD, respectively. Structures with a bromine in either ortho positions with respect to the hydroxy group competed more efficiently with T(3) binding to xTTR and the xTR LBD. 3,3',5-Tribromobisphenol A and 3,3',5,5'-tetrabromobisphenol A, at 0.1-1.0 microM, exerted both T(3) agonist and antagonist activities in the T(3)-responsive reporter gene assay. Sera obtained from fetal bovine and bullfrog tadpoles weakened the T(3) agonist and antagonist activities of 3,3',5-tribromobisphenol A, but not the T(3) antagonist activity of o-t-butylphenol, for which xTTR has no significant affinity. The T(3) agonist and antagonist activities of 0.5 microM 3,3',5-tribromobisphenol A were confirmed in the in vivo, short-term gene expression assay in premetamorphic X. laevis tadpoles using endogenous, T(3)-responsive genes as molecular markers. Our results suggest that 3,3',5-tribromobisphenol A affects T(3) binding to xTTR and xTR and that it interferes with the intracellular T(3) signaling pathway.

Antioxidant activities and phenolic contents of 26 species extracts from 20 botanical families grown in north-western Himalaya were investigated. Antioxidant activities were determined using DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging and ferric reducing antioxidant power (FRAP) assays. Total phenolic content (TPC) was determined using a Folin-Ciocalteu assay. Quantitative and qualitative analysis of phenolic compounds was also carried out by reverse phase high performance liquid chromatography (RP-HPLC) using diode array detector (DAD). Major phenolics determined using RP-HPLC in analyzed species were gallic acid, chlorogenic acid, p-hydroxy benzoic acid, caffeic acid, vanillic acid, syringic acid, p-coumaric acid and ferulic acid. Antiradical efficiency (1/EC50) determined using DPPH radical scavenging assay ranged from 0.13 to 5.46. FRAP values ranged from 8.66 to 380.9 μmol Fe(II)/g dw. Similarly, the total phenolic content in the analyzed species varied from 3.01 to 69.96 mg of gallic acid equivalents (GAE)/g dry weight. Gallic acid was found in the majority of the samples, being most abundant compound in Syzygium cumini bark (92.64 mg/100 g dw). Vanillic acid was the predominant phenolic compound in Picrorhiza kurroa root stolen (161.2 mg/100 g dry weight). The medicinal plants with highest antioxidant activities were Taxus baccata and Syzygium cumini. A significant positive correlation, R 2 = 0.9461 and R 2 = 0.9112 was observed between TPC determined using Folin-Ciocalteu method and antiradical efficiency and FRAP values respectively, indicating that phenolic compounds are the major contributor of antioxidant activity of these medicinal plants.

Radical-scavenging antioxidants play crucial roles in the protection of unsaturated oils against autoxidation and, especially, edible oils rich in omega-3 because of their high sensitivity to oxygen. Two complementary tools are employed to select, among a large set of natural and synthetic phenols, the most promising antioxidants. On the one hand, density functional theory (DFT) calculations provide bond dissociation enthalpies (BDEs) of 70 natural (i.e., tocopherols, hydroxybenzoic and cinnamic acids, flavonoids, stilbenes, lignans, and coumarins) and synthetic (i.e., 2,6-di-tert-butyl-4-methylphenol (BHT), 3-tert-butyl-4-hydroxyanisol (BHA), and tert-butylhydroquinone (TBHQ)) phenols. These BDEs are discussed on the basis of structure–activity relationships with regard to their potential antioxidant activities. On the other hand, the kinetic rate constants and number of hydrogen atoms released per phenol molecule are measured by monitoring the reaction of phenols with 2,2-diphenyl-1-picrylhydrazyl (DPPH•) radical. The comparison of the results obtained with these two complementary methods allows highlighting the most promising antioxidants. Finally, the antioxidant effectiveness of the best candidates is assessed by following the absorption of oxygen by methyl esters of linseed oil containing 0.5 mmol L−1 of antioxidant and warmed at 90 °C under oxygen atmosphere. Under these conditions, some natural phenols namely epigallocatechin gallate, myricetin, rosmarinic and carnosic acids were found to be more effective antioxidants than α-tocopherol.

The growing demand for organic food in the world requires the assessment of the value aspects of food quality, its safety, nutritional content and biological-physiological process. Fruits and vegetables are good sources of natural antioxidants containing many different antioxidant components. These antioxidants include carotenoids, vitamins, phenolic compounds, flavonoids, dietary glutathione and endogenous metabolites which have been shown to function as singlet and triplet oxygen quenchers, free radical scavengers, peroxide decomposers, enzyme inhibitors, and synergists. Phenolic compounds are found in most fruits and vegetables (Zhang, Hamauzu, 2005). Carrots and their fresh produce (shredded carrots, sliced carrots and carrot juice) may protect humans against certain types of cancer and cardiovascular diseases (Krinsky, Johmson, 2005). Carrots contain mainly hydroxycinnamic acids and derivatives. Among them, chlorogenic acid is a major hydroxycinnamic acid, representing from 42.2% to 61.8% of total phenolic compounds (Wang et al., 2006). In addition to the above mentioned compounds found in natural foods, vitamins C and E, beta-carotene and tocopherol are known to possess antioxidant potential. The aim of the research was to determine the total antioxidant activity and phenolic compounds which operate as free radical scavengers, peroxide decomposers, enzyme inhibitors and synergists. Carrot breed Neptun was obtained from Lithuanian Institute of Horticulture. Correlations between antioxidant activity and phenolic compounds were determined by using three drying methods (carrots were sliced and dried in desiccator at +40 °C and lyophilised under vacuum conditions (freeze-dried) by –72 °C for sample preparation. Antioxidant activity was determined by using DPPH radicals spectrophotometrically. The influence of drying method was not significant p > 0.05, but solvent concentration showed significant correlation with antioxidant activity and phenolic compound (p < 0.05). Among the weight of raw material and various ratios of methanolic extracts, significantly the best antioxidant activity was shown by 0.5 g and 75% of sliced desiccated, freeze-dried and pressed desiccated samples The total phenolic content of carrot material investigated during this research varied from 0.07 to 0.31 mg/ml of the methanolic carrot extracts and from 1.51 to 7.01 mg / g of dry carrot content, expressed by gallic acid equivalent (GAE). The time effect for DPPH scavenging was significant until 30 min (p < 0.05). If the reaction achieved a plato effect (balance), approx. 80% of antioxidant activity, the time effect was not significant (p > 0.05).

Substitution and torsional effects on the energetics of homolytic N–H bond cleavage in diphenylamines

In the present study, the influence of heating on the evolution of oxidative indices, antioxidant activity, phenolic and volatile compounds in monovarietal extra virgin olive oils (EVOOs) obtained from Leccino, Istarska bjelica, and Buža cultivars was investigated. The samples were submitted to heating in an air oven (180 °C and 220 °C), simulating usual roasting conditions typical for Mediterranean cuisine. The decreases in the oxidative indicators, phenolic and volatile compounds were more pronounced at higher heating temperatures, underlining the temperature dependency of the oxidative degradation during heating conditions. Despite this, it must be emphasized that a significant amount of phenolic compounds and antioxidative activity remained preserved after the heating treatment. Each oil cultivar showed some specificity during the course of the thermal degradation. Hydroxytyrosol acetate among phenolic compounds and octanal, (E)-2-octenal, hexanal, 3-pentanone, and 1-penten-3-one among the volatiles were underlined as possible markers of thermal oxidation. Principal component analysis revealed that the content of volatile compounds in monovarietal EVOO samples distinguished samples primarily by the heating temperature, while the changes in the phenolic compounds were cultivar-dependent aside from being influenced by the temperature of heating.

Kiwi and pepino fruits are most valuable fruits as they contains substantial amounts of nutrients and bioactive compounds. These fruits exhibited several health potentials such as antioxidant, antiinflammatory, antiobesity, antihyperlipidemia, and anticancer properties. However, studies on the effect of microwave and conventional drying methods on the antioxidant activity and bioactive compounds of kiwi and pepino fruits are limited. Therefore, this study was conducted to assess the effect of microwave and oven drying methods on antioxidant activity, total phenolic, and phenolic compounds of kiwi and pepino fruits. Drying of the fruit samples was carried out using conventional (70°C for 20h) and microwave (720W for 3min) ovens. 1,1-diphenyl-2-picrylhydrazyl scavenging and colorimetric Folin-Ciocalteu assays were used to assess the antioxidant activity and total phenolic contents, respectively, of fresh and dried fruits. Both drying methods significantly (p < 0.05) decreased the moisture contents of both fruits compared to untreated controls. Concomitantly, drying methods also enhanced (p < 0.05) antioxidant activity and total phenolic content of both fruits with the highest improvement being observed for microwave-dried fruits compared to untreated controls. In addition, a significant increase was observed in catechin and 1,2-dihydroxybenzene content of kiwi and pepino after drying process. However, microwave drying method reduced the amount of 3,4-dihydroxybenzoic acid in kiwi (ranging from 34.120 to 9.350mg/100g) and pepino (varied from 33.414 to 15.445mg/100g). Generally, the highest antioxidant activity and phenolic contents were reported in microwave oven dried samples, followed by samples dried in oven and fresh fruits. The results revealed that microwave drying could be more useful in fruit drying than conventional drying. In addition, dried kiwi and pepino fruits contains substantial quantities of phenolic compounds with high antioxidant activity compared to fresh fruits, and thus they are considered as healthy food.

Mango (Mangifera indica) and guava (Psidium guajava) seeds have several pharmaceutical applications and biological activities because as they have been recognized with different bioactive molecules (phenolic compounds) such as flavonoids, phenolic acids, and catechins, so they have antioxidant and anticancer activities. The aim of the present study was to assess in vitro antioxidant and anticancer activities of successive extracts and semi-purified fractions from mango seeds. In this work, mango and guava seeds were collected and extracted using two solvents (ethanol 70% and ethyl acetate) followed by phytochemical screening and determination of biological activities such as antioxidant activity using five assays (DPPH, ABTS, KMnO4, Methylene blue and H2O2) additionally the antiradical activity and hybrid reaction for ethanolic extract of mango seeds as promising extract. The total phenolic, flavonoid, and catechin compounds were determined for all successive extracts, and finally, the anticancer activity of extracts was evaluated using MTT assay against HepG2 cell line and phenolic compounds were identified by HPLC. The phytochemical screening and TLC showed the primary investigation for phenolic compounds of ethanol extracts of both kind of seeds and only ethyl acetate of guava extract as promising extracts. However, HPLC determination of these three extracts showed high amount of gallic acid, naringenin, ellagic acid, and ferulic acid as they have anticancer and antioxidant activities. The antioxidant tests showed that the ethanolic mango extract is the highest antioxidant extract against DPPH by 84.0%, but recorded 82.0% with methylene blue and ABTS assays when compared with ascorbic acid. The ethyl acetate of guava extract showed strong cytotoxic effect with IC50 75.5 μg/mL against HepG2 cell line in all tested concentrations. From the obtained results, it could be concluded that mango ethanolic extract and its fractions are the most promising as antioxidants and ethyl acetate of guava extract the most promising in the anticancer activity.

In this current special issue, different aspects related to phenolic compounds in fruit beveragesare presented.[...]