Organic Sunscreens—Biological Activity from an Enzymatic Perspective

Selected organic sunscreens from different chemical families were investigated in the context of their ability to inhibit butyrylcholinesterase using novel Multiple Linear Regression, Artificial Neural Network and Support Vector Regression models based on a set of six independent variables commonly associated with compounds’ absorption and distribution properties. It was established that the descriptors that have a particularly strong, positive influence on the ability of compounds to inhibit BChE expressed as pIC₅₀ are the count of rotatable bonds (nRot) and lipophilicity (log D); pIC₅₀ is negatively correlated with flexibility (Flex), fraction of sp3 carbon atoms (F_sp3), caco-2 permeability (caco2) and plasma protein binding ability (PPB). The sunscreens that are likely to be particularly strong BChE inhibitors are Ethylhexyl Triazone (ET), Diethylhexyl Butamido Triazone (DOBT), Octocrylene (OCR) and Diethylamino Hydroxybenzoyl Hexyl Benzoate (DHHB), although in must be stressed that ET and DOBT are outside the chemical space of the reference compounds.