From chain length to cell death: mechanistic basis for ROS-mediated apoptosis induced by saturated fatty acids

Fatty acid ethanolamides (FAEs) are bioactive lipids with amphiphilic properties and potential as prodrugs. In this study, a homologous series of FAEs (C8:0-C18:0) was evaluated for solubility, hydrophobicity, rheology, reactive oxygen species (ROS) generation, mitochondrial membrane potential (MMP), apoptosis, and molecular docking affinity. Medium-chain FAEs (C8:0-C10:0) exhibited high solubility and limited apoptotic activity, whereas C12:0-MEA exhibited a distinct profile characterized by enhanced ROS, MMP disruption, and pronounced apoptosis. Long-chain FAEs (C14:0-C18:0) demonstrated greater hydrophobicity and enhanced apoptotic effects, mediated through both ROS-dependent and independent pathways. Molecular docking revealed interactions of C12:0- and C16:0-C18:0-MEA with cannabinoid receptors (PDB IDs: 5TGZ and 6PT0), supporting a mechanistic basis for their biological activity. Principal component analysis identified acyl chain length as the dominant determinant of physicochemical and biological behavior, effectively distinguishing FAEs based on their solubility and bioactivity profiles. These findings underscore the role of chain length in modulating ROS generation, and apoptotic activity. The distinct activity profile of C12:0-MEA emphasizes its potential as a targeted prodrug, providing controlled bioactivity while minimizing off-target toxicity. This study delivers a comprehensive structure-function characterization of FAEs, offering insights for designing lipid-based prodrugs with optimized physicochemical and biological properties for therapeutic applications.