Figure 2
Chemical structure of the main cinnamic acids. Cinnamic acid R1 = R2 = R3 = R4 =H, o-coumaric acid: R2 = OH, p -coumaric acid: R3 = OH; caffeic acid: R2 = R3 = OH; ferulic acid: R2 = OCH3 and R3 = OH.
Chemical structure of the main cinnamic acids. Cinnamic acid R1 = R2 = R3 = R4 =H, o-coumaric acid: R2 = OH, p -coumaric acid: R3 = OH; caffeic acid: R2 = R3 = OH; ferulic acid: R2 = OCH3 and R3 = OH.