Synthesis and Biological Activities of Ferulic Acid–Amino Acid Derivatives

Three series of ferulic acid derivatives (feruloylaminoacid benzyl ester or methyl ester, feruloylaminoacid, and 4-O-[N-carbobenzyloxy)-aminoacyl]ferulic acid) were synthesized newly, and their superoxide dismutase (SOD)-like, platelet aggregation (PA)-in-hibitory, tyrosinase-inhibitory,, and angiotensin converting enzyme (ACE)-inhibitory activities were evaluated. 4-O-[N-(Carbobenzyloxy)isoleucyl]ferulic acid (20) and 4-O-[N-(carbobenzyloxy)prolyl]ferulic acid (21) showed potent PA-inhibitory activities and tyrosinase-inhibitory activities, while they also had SOD-like activities at the same level as ferulic acid.