Isolation, Identification, and Structure of a Potent Alkyl-Peroxyl Radical Scavenger in Crude Canola Oil, Canolol

Abstract

Alkylhydroperoxides in oxidized oil are undesirable components because they become alkylperoxyl radicals (ROO*) in the presence of heme, hemoglobin, or myoglobin in red meat. ROO* are biochemically reactive and damage nucleic acids and proteins, thereby harming living cells. We isolated a component, a highly potent ROO* scavenger, from crude canola oil (rapeseed), which we designated canolol, and identified its chemical structure, 4-vinyl-2,6-dimethoxyphenol. The canolol content of crude canola oil greatly increased after the seed was roasted as compared with that from unroasted seed, but it decreased in highly purified oil. This anti-ROO* activity was highest in crude oil, deceased after each refining step, and was lowest in highly purified refined oil. Canolol was thus generated during roasting. As shown previously, canolol is one of the most potent anti-ROO* components in crude canola oil and its potency is much greater than that of well-known antioxidants, including alpha-tocopherol, vitamin C, beta-carotene, rutin, and quercetin.

Cold-pressed and hot-pressed rapeseed oil: The effects of roasting and seed moisture on the antioxi- dant activity, canolol, and tocopherol level

“…They have also shown that there is a synergistic effect between the different phenolic compounds in rapeseed oil. Such an effect is also confirmed by Wakamatsu et al (2005) and by Spielmeyer et al (2009), who reported no loss of tocopherols during the thermal processing of seeds and explained this as being due to the protective activity of canolol. Moltke-Sørensen et al (2013) showed the high antioxidant activity of canolol in an oil-water emulsion, which in comparison to other compounds is ordered as follows: BHT > canolol > sinapine > canola extract > sinapic acid.…”

“…In studies examining the levels of tocopherols in rapeseed oil produced from roasted seeds, some authors observed an increase in the amounts of particular tocopherols and plastochromanol-8 (Siger et al, 2015;Shrestha and De Meulenaer, 2014). Neither Wakamatsu et al (2005) nor Spielmeyer et al (2009) found any significant differences in the tocopherol content of canola oil from unroasted and roasted raw material. The lack of a decrease in tocopherol levels under the influence of high-temperature roasting of the rapeseed is often explained by the synergistic interaction of phenolic compounds (here, mainly canolol) -the amount of which increases in proportion to the temperature and roasting duration (Matthäus, 2013a;Siger et al, 2015).…”

“…It is probable that the variety of rape is of great significance for this phenomenon. Canolol is lost during the production of refined oil, but because of its lipophilic nature, it can be added back to the oil after being isolated from the pressing (Wakamatsu et al, 2005;Zacchi and Eggers, 2008).…”

“…Canolol has a greater ability to prevent lipid oxidation than a number of other known antioxidants, such as tocopherols, ascorbic acid, β-carotene, rutin, and quercetin (Koski et al, 2003;Wakamatsu et al, 2005). Terpinc et al (2011) assessed the antioxidant activity of canolol and compared it to that of sinapic acid and other phenolic acids and derivatives.…”

In vivo Cytogenetic Effects of Multiple Doses of Dietary Vegetable Oils

“…Soybean oil and olive oil had mild effects on myocardial structure (Aguila et al, 2004). Recently, a potent antioxidant named canolol was isolated from crude canola oil and its potency was found to be greater than that of some well-known antioxidants, including a-tocopherol, vitamin C and quercetin (Wakamatsu et al, 2005).…”