Comprehensive Triterpenoid Saponin Profiling of Beta vulgaris L. Root Extracts and Their Functional Application in Cleansing Gels.

Plant-derived bioactive ingredients are increasingly valued in cosmetic formulations due to their multifunctionality and natural origin. This study evaluated beetroot (Beta vulgaris L.) extracts as plant-derived surfactant-supporting ingredients in cleansing gels, with DPPH radical-scavenging response assessed as a secondary formulation-level endpoint. Three cultivars-Dark Red Round (red), Boldor (yellow), and Snow Ball (white)-were characterized for triterpenoid saponin composition and functional performance. Unlike previous studies focused primarily on the phytochemical characterization of beetroot saponins, the present work integrates cultivar-dependent chemical profiling with comparative evaluation of the corresponding extracts in the same cleansing formulation. UHPLC-CAD-QTOF-HRMS/MS analysis tentatively annotated 30 triterpenoid saponins and revealed cultivar-dependent differences. Semi-quantitatively estimated total saponin concentrations were 17.5, 15.1, and 11.6 g/kg dry extract for Dark Red Round, Boldor, and Snow Ball, respectively, with oleanolic acid-based saponins predominating. Cleansing gels containing 1% (w/w) beetroot extract were evaluated for physicochemical, rheological, and functional properties. Extract-enriched gels showed increased foamability, cultivar-dependent foam stability, and pseudoplastic shear-thinning behavior. Surface tension remained substantially lower than that of water but increased moderately after incorporation of the extracts, indicating modification rather than further surface-tension lowering of the existing surfactant system. DPPH screening showed cultivar-dependent radical-scavenging responses, with the highest inhibition observed for the red beetroot formulation (8.94%). Overall, triterpenoid saponin-containing beetroot extracts modified the functional performance of the cleansing formulations, particularly their foaming and oil-emulsification properties. These findings support their potential as sustainable, plant-derived surfactant-supporting ingredients in multifunctional cleansing formulations.