Agro-Industrial Residues as Sources of Dermo-Cosmetic Enzyme Inhibitors: Extraction Strategies, Matrix Effects, and Cosmetic Potential

Agro-industrial residues have emerged as promising sources of bioactive compounds for dermo-cosmetic applications, particularly as inhibitors of collagenase, elastase, hyaluronidase, and tyrosinase. However, the interpretation of reported inhibitory activities is frequently complicated by variations in extraction strategies, matrix composition, assay design, and methodological rigor. This critical narrative review examines how these factors collectively influence the reliability, comparability, and translational relevance of enzyme inhibition data obtained from residue-derived extracts. The literature was analyzed using a framework-oriented approach based on representative peer-reviewed studies selected according to their methodological quality, experimental design, and mechanistic relevance. The analysis integrates three complementary dimensions: extraction and processing strategies, compositional complexity of the recovered matrices, and evidence quality supporting the reported bioactivities. The reviewed literature demonstrates that enzyme inhibition is rarely an intrinsic property of isolated compounds but rather an emergent behavior arising from complex physicochemical systems in which synergistic interactions, matrix effects, and assay-dependent artefacts frequently influence the observed responses. The widespread reliance on simplified in vitro screening methods, often without dose–response evaluation, kinetic characterization, or adequate control of assay interference, remains a major obstacle to reproducibility and cross-study comparison. Based on this analysis, an integrative framework is proposed to guide the interpretation of enzyme inhibition in complex botanical extracts by explicitly linking process design, matrix composition, and methodological evidence. This perspective provides a more robust basis for the identification, validation, and industrial translation of sustainable bioactive ingredients obtained from agro-industrial residues for next-generation dermo-cosmetic formulations.