Comparison of photosensitivities of resveratrol-based carbamates with cholinesterase inhibitory activity

• Carbamate derivatives of resveratrols display promising cholinesterase inhibitions • Stilbene-like resveratrols are prone to trans-cis photoisomerization • The efficiency of this process does not depend on the substituents of the benzene ring • The efficiency of the photocyclization of the cis isomers is substituent-dependent • The quantum yield of the cyclization is inversely proportional to the bioactivity Various resveratrol-based carbamates display very promising butyrylcholinesterase inhibitory activity. These stilbene-like compounds with a C=C bond are prone to a photoinduced trans-cis isomerization. Their structure may affect both properties, which may be correlated. The efficiency of the trans-cis isomerization of these compounds with various carbamate substituents on their benzene ring is very high, with quantum yields in the range of 0.21-0.32, similar to that of the analogue with a much smaller hydroxy substituent. These results indicate that the structural deviations located far from the C=C bond of these compounds hardly influence this isomerization process. Accordingly, there is no correlation between the structure-dependent biological activity and the sensitivity to trans-cis photoisomerization. Since the bioactivity of the trans -isomers of these carbamate derivatives is much stronger than of their cis -isomers, the high light sensitivity of these potential active ingredients of medicines to trans-cis isomerization warrants their protection from exposure to UV radiation during both their production and storage, as well as their application. The second step of the photochemical transformation of these compounds is the cyclization of their cis -isomers. Deviating from the photoinduced trans-cis isomerization, the tendency of these derivatives toward cyclization indicates a relatively strong connection to the structural features, similarly to their bioactivity. The efficiency of cyclization is inversely proportional to the biological activity. The most active is the carbamate derivative with the bulkiest substituent, displaying a negligible tendency toward cyclization, while the bioactivity of its hydroxy analogue with the highest efficiency of cyclization is two orders of magnitude lower.