Phenolic compound antioxidative activity

Di.scusses compositional and lipid characteristics, phenolic compounds, antioxidant activities, and allergens of tree nuts... 

Pereira JA, Pereira APG, Ferreira ICFR, Valentao P, Andrade PB, Seabra R, Estevinho L and Bento A. 2006. Table olives from Portugal phenolic compounds, antioxidant potential, and antimicrobial activity. J Agric Food Chem 54(22) 8425-8431. 

Randhir R, Lin Y-T, Shetty K. 2004. Stimulation of phenolic compounds, antioxidant and antimicrobial activities in dark germinated mung bean sprouts in response to peptide and phytochemical elicitors. Process Biochem 39 637-646. 

Polyphenylenoxide (PPO) Substituted phenols are used as monomers for the production of polyphenylenoxides, (PPOs) so they as well as phenolic degradation products can be found as emitted odor active compounds. In one case the odor of a PPO was predominantly caused by 2,6-dimethylphenol and trimethylanisol as well as by a tentatively identified substituted methoxypyrazine (Mayer and Breuer, 2004a). Another potent odorant derived from higher molecular phenolic compounds, antioxidants for example, by the influence of heat (>200 °C) and pressure is guaiacol (2-methoxyphenol) (Mayer and Breuer, 2006). 

Oxidative cellular damage by reactive oxygen species such as superoxide anion, hydroperoxy and hyassociated with various human chronic diseases, e.g. cancers, inflammation, arthritis, atherosclerosis and also with the process of ageing. Claims that diet and increased intake of nutrients exhibiting antioxidative activity have a preventative effect on chronic diseases have increased in recent years. In this context, polyphenolic compounds such as tannins, flavonoids, coumarins, lignans and caffeic acid derivatives, which are abundantly contained in a large number of medicinal plants, foods and beverages, are of particular interest for human health care because of the antioxidative properties widely found in plant phenolics. The antioxidative activity of tannins has been extensively studied in various in vitro and in vivo experimental systems and summarized in reviews [96, 97]. Such activity includes the inhibition of lipid peroxidation induced by NADPH-ADP and ascorbic acid-ADP in rat liver microsomes and mitochondria, respectively... 

In this study, we found that phenolic compounds are the major contributors to the antioxidant activity, since total phenolics and antioxidant activity showed a good correlation with a correlation coefficient of R2=0.9208. However, we note that the trunk barks of A. leiocarpus exhibit a high antioxidant activity and a low level of total phenol antioxidant. The value of correlation coefficient between total flavonoids and antioxidant activity was R2 = 0.752 only. 

PEYRAT-MAiLLARD M N, BONNELY s and BERSET c (2000) Determination of the antioxidant activity of phenolic compounds by coulometric detection, Talanta, 51, 709-16. 

Paganga, G. et al.. The polyphenolic content of fruit and vegetables and their antioxidant activities what does a serving constitute Free Radical Res., 30, 153, 1999. Maatta, K.R. et al.. High-performance liquid chromatography (HPLC) analysis of phenolic compounds in berries with diode array and electrospray ionization mass spectrometric (MS) detection Rihes species, J. Agric. Food Chem., 51, 6736, 2003. 

Phytochemicals present in fruits and vegetables are very diverse, such as ascorbic acid, carotenoids, and phenolic compounds (Liu 2004 Percival and others 2006 Syngletary and others 2005 Yahia and others 2001a, 2001b). Plant polyphenols are ubiquitous in the diet, with rich sources being tea, wine, fruits, and vegetables they demonstrate considerable antioxidative activity in vitro, which can have important implications for health (Duthie and others 2000). 

Fresh peppers are excellent sources of vitamins A and C, as well as neutral and acidic phenolic compounds (Howard and others 2000). Levels of these can vary by genotype and maturity and are influenced by growing conditions and processing (Mejia and others 1988 Howard and others 1994 Lee and others 1995 Daood and others 1996 Simmone and others 1997 Osuna-Garcia and others 1998 Markus and others 1999 Howard and others 2000). Peppers have been reported to be rich in the provitamin A carotenoids (3-carotene, a-carotene, and (3-cryptoxanthin (Minguez-Mosquera and Hornero-Mendez 1994 Markus and others 1999), as well as xanthophylls (Davies and others 1970 Markus and others 1999). Bell peppers have been shown to exert low antioxidant activity (Al-Saikhan and others 1995 Cao and others 1996 Vinson and others 1998) or may even act as pro-oxidants (Gazzani and others 1998). 

Kahkonen MP, Hopia AI, Vurela HJ, Rauha J-P, Pihlaja K, Kujala TS and Heinon M. 1999. Antioxidant activity of plant extracts containing phenolic compounds. J Agric Food Chem 47 3954-3962. 

Le Tutour B and Guedon D. 1992. Antioxidative activities of Olea europaea leaves and related phenolic compounds. Phytochemistry 31 1173-1178. 

Aaby K, Hvattum E and Skrede G. 2004. Analysis of flavonoids and other phenolic compounds using high-performance liquid chromatography with coulometric array detection relationship to antioxidant activity. J Agric Food Chem 52(15) 4595 1603. 

Karakaya S, El SN and Ta AA. 2001. Antioxidant activity of some foods containing phenolic compounds. Int J Food Sci Nutr 52(6) 501-508. 

Materska M and Perucka I. 2005. Antioxidant activity of the main phenolic compounds isolated from hot pepper fruit (Capsicum cmnuum L.). J Agric Food Chem 53(5) 1750-1756. 

Stewart RJ, Askew EW, McDonald CM, Metos J, Jackson WD, Balon TW and Prior RL. 2002. Antioxidant status of young children response to an antioxidant supplement. J Am Diet Assoc 102(11) 1652—1657. Stratil P, Klejdus B and Kuban V. 2006. Determination of total content of phenolic compounds and their antioxidant activity in vegetables evaluation of spectrophotometric methods. J Agric Food Chem... 

Stratil P, Klejdus B and Kuban V. 2007. Determination of phenolic compounds and their antioxidant activity in fruits and cereals. Talanta 71 (4) 1741—1751. 

Some steroid molecules (estrone, estradiol, and estriol) have phenolic hydroxyl in the ring A (Figure 29.12) and therefore, are able to react as free radical scavengers. In 1987, Japanese authors [264,265] showed that all these compounds inhibited iron adriamycin- or iron ADP-ascorbate-dependent phospholipid and liposomal lipid peroxidation. Later on, most attention was drawn to the study of antioxidative properties of estradiol-17(3 (estrogen E2) it has been proposed that E2 antioxidant activity may contribute to cardioprotection observed after estrogen therapy in postmenopausal women. The necessity for the phenolic hydroxyl has been shown by studying the effects of several estrogens on LDL oxidation. It was found [266]... 

Similar to some other antioxidants, pyrrolopyrimidines do not contain active free radical scavenging groups such as phenolic or thiolic substituents. At present, at least two different mechanisms of their antioxidant activity have been proposed [307], It was suggested that pyrrolopyrimidines, which are electron donating compounds, can be oxidized by hydroxyl or peroxyl radicals or hydroxylated by cytochrome P-450 forming phenolic metabolite... 

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