Phenolics resveratrol

Different techniques or solvents used for saponin extraction may affect the purity of the extract. This was shown by different contents of sarsaponin in four commercial products of Yucca schidigera extract (Singer et al. 2008). Y. schidigera powder contained not only saponins but also phenolics (resveratrol, yuccaol) (Piacente et al. 2005), glycoprotein and stilbenes. These other compounds were present in non-butanol extractable fraction and exert several properties such as antiinflammatory, antioxidant (Cheeke et al. 2006), reducing air ammonia concentration and fecal odour (Piacente et al. 2005). Therefore, different results on the use of Yucca extract in the ruminant feed can be influenced by the presence of other compounds in the extract. 

The phenol resveratrol, found in the skin of red grapes, is under investigation for its potential anti-cancer,... 

Owing to the fact that ethyl ethers are especially effective substrates for CYP1A1 [184], the probe possesses an ethyl group on the phenolic oxygen of the trimethyl lock. In vitro, fluorescence was manifested by CYP1A1 isozyme with Kcat/KM 8.8 x 103 M-1s 1 and KM 0.09 pM. In cellulo, the probe revealed the induction of cytochrome P450 activity by the carcinogen 2,3,7,8-tetrachlorodi-benzo-p-dioxin (TCDD), and its repression by the chemoprotectant resveratrol. 

A similar effect was observed in other fruits and vegetables, where UV-C treated strawberries showed a higher increment of phenols and PAL activity 12 hours after treatment than unirradiated (control)(Pan and others 2004), which could be the reason for the increment in total phenol constituents (Lancaster and others 2000). UV-C and UV-B caused a two- and threefold increase in content of resveratrol (a grape phenol constituent). Thus, mature Napoleon grapes that had been irradiated with UV-C light can provide up to 3 mg of resveratrol per serving (Cantos and others 2001). Therefore, UV-C treatments clearly cause a benefit effect, increasing total phenol content, which can be mainly attributed to the increment of PAL activity. 

Wine Phenolics (mg/1) Gallic acid (qg/ml) Rutin (jUg/ml) Trans- resveratrol (qg/ml) Quercetin (Ug/ml)... 

OH groups attached to benzene rings are termed phenols (Chapter 7). Since there are three such structures in this molecule, resveratrol is a polyphenol. 

Fig. 6. Phenolic constituents curcumin and the gingerols isolated from Zingiber officinale L. and Curcuma longa L., and resveratrol from a red wine extract. All have significant inhibitory activities on Cag- - strains of HP.

For the red wines (82-84), which were injected directly into the HPLC without sample preparation, a ternary-gradient system using aqueous acetic acid (1% and 5% or 6%), and acidified acetonitrile (acetonitrile-acetic acid-water, 30 5 6) was used for cinnamic acid derivatives, catechins, flavonols, flavonol glycosides, and proanthocyanidins. Due to the large number of peaks, the gradient was extended to 150 min for the resolution of many peaks of important phenolics. This direct injection method was able to separate phenolic acids and esters, catechins, proanthocyanidins, flavonols, flavonol glycosides, and other compounds (such as tyrosol, and rrans-resveratrol) in wine in a single analysis. However, use of acetic acid did not permit the detector (PDA) to be used to record the UV spectra of phenolics below 240 nm (84). 

Resveratrol has also been reported to offer protection against cardiovascular disease, such as coronary heart disease. The effects of resveratrol on factors implicated in the development of coronary heart disease - human platelet aggregation and the synthesis of eicosanoids (lipids) from arachidonate by platelets - were investigated and compared with the actions of other wine phenolics - catechin (1.39), epicatechin (7.18a), and quercetin (1.43) - and the antioxidants a-tocopherol (7.10a), hydroquinone and butylated hydroxytoluene. Resveratrol and quercetin demonstrated a dose-dependent inhibition of platelet aggregation, whereas the other compounds tested were inactive. Resveratrol also inhibited the synthesis of the eicosanoids in a dose-dependent manner, whereas the other phenolics were less effective of not effective at all. Removal of the alcohol from the wine did not diminish the effect on platelet aggregation (Pace-Asciak et al., 1995 Goldberg et al., 1995). 

Auger C, Teissedre PL, Gerain P, Lequeux N, Bomet A, Serisier S, Besancon P, Caporiccio B, Cristol JP, Rouanet JM. 2005. Dietary wine phenolics catechin, quercetin, and resveratrol efficiently protect hypercholesterolemic hamsters against aortic fatty streak accumulation. J Agric Food Chem 53 2015-2021. 

The above reactions may play a role in copper-mediated DNA damage, and the effect of the frans-resveratrol, a naturally occurring phenolic antioxidant, has been studied in this context (Burkitt and Duncan 2000). 

Finally, we tested the actions of other phenolic compounds derived from various sources including fruits, vegetables, and plants. Among those tested, piceatannol, a natural resveratrol analog, was the most potent, followed by morin and myricetin. In contrast, quercetin and kaempferol were ineffective. Moreover, phenolic acids— namely, tannic and gallic acids—were the only ones that were neuroprotective in our model, as summarized in Table 6.1. 

The affinity of polyphenols and various resveratrol analogs to compete for specific [3H]-resveratrol binding correlated very well (r = 0.74) with their neuroprotective activity against Ap25 35-induced toxicity in primary hippocampal cell cultures. This suggests that the neuroprotective effect exerted by these phenolic compounds could be mediated by a common mechanism involving specific polyphenol plasma membrane binding sites. 

Due to the long maceration on skin, red wines are particularly rich in phenolic compounds, having higher antioxidant capacity and also higher resveratrol content than white wines. Of the high number of studies on this field, only a few focused on the botrytized white wines. 

TABLE 6.8 Resveratrol, piceid, total phenols, and antioxidant capacity (TEAC) of someTokaji and German botrytized wines. Mean values are in parentheses (adapted from Pour Nikfardjam et al, 2006, and with permission from Elsevier)... 

Chemoprevention is a strategy used to block or suppress carcinogenesis and degenerative disease using dietary or pharmacological compounds. These chemo-preventive compounds include phenols [such as tm-butyl 4-hydroxyanisole (BHA), t-BHQ (active metabolite of BHA), ethoxyquine, curcumin (from turmeric) and resveratrol (from grapes)] and sulfur compounds [such as oltiplaz, sulforaphane... 

The non-flavonoid phenolic constituents in wine are divided into hydroxybenzoic acids and hydroxycinnamic acids, volatile phenols, stilbenes and miscellaneous compounds (e.g. lignans and coumarins). Although non-colored, the non-flavonoid constituents are known to enhance and stabilize the color of red wines by intra- and intermolecular reactions. They furthermore contribute to wine flavor (volatile phenolic acids) and some of them (e.g. resveratrol) exhibit potent biological activities. 

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