Table 4.

Structural formulas of selected cinamonic acid derivatives.

Compound	R1	R2	R3	R4
cinamonic acid	H	H	H	H
p-cumaric acid	H	H	OH	H
m-cumaric acid	OH	H	H	H
o-cumaric acid	H	OH	H	H
ferulic acid	H	OCH3	OH	H
isoferulic acid	H	OH	OCH3	H
caffeic acid	H	OH	OH	H
synapic acid	H	OCH3	OH	OCH3
4-metoxycynamonic acid	H	H	OCH3	H
3,4-dimetoxycynamonic acid	H	OCH3	OCH3	H
2,4-dimetoxycynamonic acid	OCH3	H	OCH3	H