Polyhydroxylated phenylacrylic acid derivatives as new anti-tumor agents

Article abstract of DOI:10.1002/jps.2600800503

Preliminary evidence indicates that antitumor agents containing the o-dihydroxybenzene moiety exhibit enhanced antitumor activity toward malignant cells of high oxidative potential, such as melanoma cells. Based on this consideration, 11 hydroxybenzene acrylic acid derivatives of differing redox potential were prepared as potential substrates for the melanoma specific enzyme tyrosinase, that might exhibit general antitumor activity and enhanced cytotoxicity toward melanoma cells. Five of these compounds [α-cyano-β-(4-hydroxyphenyl)-, α-cyano-β-(3,4-dihydroxyphenyl)-, and α-cyano-β-(3,4,5-trihydroxyphenyl)acrylic acid (THPPA), and 3,4-dihydroxy- and 3,4,5-trihydroxybenzalcyanoacetamide] were found to be substrates for tyrosinase with k(m) values from 0.08 to 4.13 mM and V(max) values from 0.18 to 3.02. These data indicate that as the number of hydroxy groups increases, the rate of oxidation increases, and that cyanoamides were faster reacting than corresponding cyanoacids, with dicyanides the least reactive. In contrast, cyanoamides were less effective as substrates than cyanoacids. In vitro studies showed all but two compounds were active against L1210 (IC₅₀ range 21-980 μM), SK-MEL-28 (IC₅₀ range 54-950 μM), and SK-MEL-30-3 (IC₅₀ range 54-190 μM). Only THPPA was active in vivo against L1210 and B-16 melanoma.