trans-3-Hydroxycinnamic acid

Effects of germination on the nutritional properties, phenolic profiles, and antioxidant activities of buckwheat.[Pubmed: 25858540]

J Food Sci. 2015 May;80(5):H1111-9.

Germination is considered to be an effective process for improving the nutritional quality and functionality of cereals.
METHODS AND RESULTS:
In this study, changes of nutritional ingredients, antinutritional components, chemical composition, and antioxidant activities of buckwheat seeds over 72 h of germination were investigated, and the reasons for these changes are discussed. With the prolonged germination time, the contents of crude protein, reducing sugar, total phenolics, total flavonoids, and condensed tannins increased significantly, while the levels of crude fat, phytic acid, and the activity of trypsin inhibitor decreased. Phenolic compounds, such as rutin, vitexin, isovitexin, orientin, isoorientin, chlorogenic acid, trans-3-Hydroxycinnamic acid, and p-hydroxybenzoic acid increased significantly during the germination process, which may be due to the activation of phenylalanine ammonialyase. The improvement of flavonoids led to significant enhancement of the antioxidant activities of germinated buckwheat. Germinated buckwheat had better nutritional value and antioxidant activities than ungerminated buckwheat, and it represented an excellent natural source of flavonoids and phenolic compounds, especially rutin and C-glycosylflavones.
CONCLUSIONS:
Therefore, germinated buckwheat could be used as a promising functional food for health promotion.

Czech Journal of Food Sciences,2015, 33(3):210-6.

Details of the Antioxidant Mechanism of Hydroxycinnamic Acids[Reference: WebLink]

Antioxidant activities and free radical-mediated DNA strand breakages of five hydroxycinnamic acids were examined. Kinetic analysis of a stable galvinoxy (GO•)-scavenging reaction of hydroxycinnamic acids demonstrated that the molecular structure and the reaction medium were two important factors affecting the antioxidant mechanism and activity.
METHODS AND RESULTS:
In methanol, the kinetic process of the compounds, which have electron-donating groups (-OH, -OCH3) in the ortho- or para-position of 4-OH, was primarily governed by the sequential proton loss electron transfer (SPLET mechanism). While, in ethyl acetate, the reaction mechanism is predominantly direct hydrogen atom transfer (HAT mechanism). But for the compounds having only one hydroxyl, both in ethyl acetate and methanol, the reaction mechanism is only HAT. At the same time, the compound bearing o-diphenoxyl is not the most active one in our tested environment.