Canolol

For example, the main phenol with antioxidative and antimutagenic activities that occurs in crude canola oil is 2,6-dimethoxy-4-vinylphenol known as canolol, which is produced from syringic acids. The major products of caffeic acid pyrolysis at 225 °C are pyrocatechol, 4-vinylpyrocatechol and 4-ethylpyrocatechol (see Section 8.3.4). A more complex mixture of products arises by pyrolysis of lignin, in the smoke condensates used in the meat industry, more than 150 different phenols, and dozens of aromatic alcohols, phenolic acids and hydroxylated heterocyclic compounds have been identified. 

Kuwahara H., Kanazawa A., Wakamatu D., Morimura S., Kida K., Akaike T., Maeda H. Antioxidative and antimutagenic activities of 4-vinyl-2,6-dimethoxyphenol (canolol) isolated from canola oH. Journal of Agricultural and Food Chemistry, 52 4380-4387 (2004). 

Because of its potent bioactive potential, the increase of canolol content in rape-seed oil would theoretically produce oil with enhanced food value and as well as longer shelf life (Spielmeyer et al, 2009). Canolol is thermally unstable, even though it is being produced from sinapic acid at higher temperatures. An exponential decrease in the canolol content from 81.4 to 11.0 g/g in oil was observed when it is exposed to a heat treatment up to a temperature of 180°C for 20 min. 

Recently, Harbaum-Piayda et al. (2010) demonstrated the possibility of new compounds such as cis- and tratis-diastereomers of 4-vinylsyringol dimer [cis-4,6-dimethoxy-5-hydroxy-l-methyl-3-(30,50-dimethoxy-40-hydroxyphenyl) indane and trani-4,6-dimethoxy-5-hydroxy-l-methyl-3-(30,50-dimethoxy-40-hydroxyphenyl) indane] and the vinylsyringol trimer in commercial rapeseed oils, as well as in a commercial by-product of oil refining, the deodistillate. The newly identified canolol dimer was present in the deodistillate of processed rapeseed oil in significant amounts (-3.50 g/kg). Trace amounts of phenylindane was also detected in commercial rapeseed oils. According to Harbaum-Piayda et al. (2010), this newly identified phenylindane compound had a high antioxidative potential and stressed its potential as an important phenolic compound to add value to the commercial deodistillate and rapeseed oils. 

Vinylphenols, useful compounds for industrial applications, were obtained by decarboxylation of 4-hydroxycinnamic acids under microwave irradiation in the presence of l,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as base and basic aluminium oxide as solid support (Bernini et al., 2007). This methodology can be applied for the synthesis of canolol. Terpinc et al. (2011) prepared 4-vinylphenol, 4-vinylguaiacol, 4-vinylsyringol and 4-vinylcatechol by thermal decarboxylation of the corresponding hydroxycinnamic acids p-coumaric, ferulic, sinapic and caffeic acid, respectively, of these 4-vinylsyringol/canolol is more important. LC-MS followed by NMR analysis was used for confirmation of canolol. 

Generally, the canolol is analysed by normal-phase HPLC/UV and the structure is confirmed by NMR and MS techniques. The component which showed the best radical scavenging activity in the polar fraction was obtained in the study conducted by Koski et al. (2003). The authors performed NMR spectrometry and mass spectrometry and identified as vinylsyringol (4-hydroxy-3,5-dimethoxystyrene, or 2,6-dime-thoxy-4-vinylphenol). This compound exhibited a UV spectrum characteristic of... 

Wakamatsu et al. (2005) were successful in determining the chemical structure of canolol. They confirmed the absence of neither nitrogen nor sulphur in the molecular structure of canolol using elemental analysis. The molecular mass of canolol is estimated to be 180 using a high-resolution MS of atmospheric pressure chemical ionization (APCl) plus LC/MS method. Based on these results, Wakamatsu et al. (2005) proposed the structure of canolol as C,oH,203 and with the help of H-NMR data, the authors concluded that this active component is 4-vinyl-2,6-dimethoxy-phenol. Canolol had absorption peaks at 218 and 269 nm. The molecular extinction coefficient in water was 29,000 at 218 mn and 13,000 at 269 nm. Canolol exhibited a fluorescence emission maximum at 325 nm which was used for quantifying upon HPLC (Wakamatsu et al., 2005). 

Koski et al. (2003) showed that canolol is attributed to the better stability of the crude rapeseed oils and the polar fraction containing vinylsyringol showed lipid... 

The DNA strand breakage induced by the endogenous oxidant ONOO has been prevented by canolol and it followed in a dose-dependent manner. Antioxidative effect or terminations of oxy radical-induced strand breaks are responsible to this. The capacity of canolol to suppress ONOO-induced cell damage, killing of bacteria and mammalian cells and bacterial mutation as well as plasmid DNA strand breakage have been established with this study (Kuwahara et al., 2004). Canolol prevented oxidative stress-induced cellular apoptosis to a significant extent in SW480 cells. 

Canola oil is conventional cooking oil in many countries. The canolol content of crude canola oil (220-1200 ppm) could provide doses similar to that used in a study by Cao et al. (2008). It should be noted, however, that the concentration in refined canola oil is significantly lower (Wakamatsu et al., 2005) so that alternative strategies have to be proposed. Supplementation of canola oil with extracted or synthesized canolol will be an effective method to enrich and add value to the oils. 

Cao X, T sukamoto T, Seki T, TanakaH, Morimura S, Cao L. 2008.4-Vinyl-2,6-dimethoxyphenol (canolol) suppresses oxidative stress and gastric carcinogenesis in Helicobacter pylori infected carcinogen-treated Mongolian gerbils. International Journal of Cancer, 122 1445-1454. 

Eid YZ. 2010. Novel antioxidant canolol reduces glucocorticoid induced oxidative stress in broiler chickens. Egyptian Poultry Science, 30(IV) 917-926. 

Galano A, Francisco-Marquez M, Alvarez-Idaboy JR. 2011. Canolol A promising chemical agent against oxidative stress. Journal of Physical Chemistry B, 115(26) 8590-8596. 

Maeda H, Tsukamoto T, Tatematsu M. 2009. Anti-inflammatory agent and cancer-preventive agent comprising canolol or prodrug thereof and pharmaceutical, cosmetic and food comprising the same, 2009, United States Patent Apphcation 20090163600, Application Number 12/294972. 

Spielmeyer A, Wagner A, Jahreis G. 2009. Influence of thermal treatment of rapeseed on the canolol content. Food Chemistry, 112 944—948. 

Wakamatsu D. 2001. Isolation and identification of radical scavenging compound, canolol in canola oil. MS Thesis, Graduate School of Natural Science, Kumamoto University,... 

Xin D, Li Z, Wang W, Zhang W, Liu S, Zhang X. 2011. Protective effect of canolol from oxidative stress-induced cell damage in ARPE-19 cells via an ERK mediated antioxidative pathway. Molecular Vision, 17 2040-2048. 

The background and detailed mechanisms of decarboxylation are very extensive, and therefore this chapter will discuss some specihc pathways of decarboxylation. In addition, we have highlighted recent cases of decarboxylation relevant to hydroxy-cinnamic acids in wine, beer and camelina and attempted to reason if such strategies can be transferred for value addition to processing of rapeseed and canola. An update on the recent thermal decarboxylation to form canolol, a phenol of interest in rapeseed and canola processing, is discussed in the last part of this chapter. 

Decarboxylation for Generation of Substituted Vinylphenols (Canolol) from Substituted Cinnamic Acid... 

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