Differential Bioactivities of Hot Water Extracts from Crepidiastrum sonchifolium according to Plant Parts and Pretreatment Conditions

Purpose: This study systematically evaluates the antioxidant, tyrosinase-inhibitory, L-DOPA oxidation–suppressive, and anti-inflammatory activities of <i>Crepidiastrum sonchifolium</i> depending on plant part, pretreatment method, and hot-water extraction condition, with the aim of proposing an optimal utilization strategy.Methods: Leaves and roots were pretreated as fresh or dried, sliced (5×5 mm) or ground (500 W, 30 s), and extracted in hot water at 70℃–100℃ for 30–120 min. Total phenolic content (TPC), total flavonoid content (TFC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, tyrosinase inhibition, L-DOPA oxidation suppression, human dermal fibroblast neonatal (HDFn) cell viability, and lipopolysaccharide (LPS)–induced tumor necrosis factor-α (TNF-α) suppression were analyzed.Results: Ground dried leaf extract obtained at 90℃ for 120 min exhibited high antioxidant activity with 21.7 mg gallic acid equivalents (GAE)/g dry weight (DW) TPC and a DPPH half-maximal effective concentration (EC<sub>50</sub>) of 4.23 mg/mL. Root extracts displayed lower antioxidant activity but stronger enzymatic inhibitory activities (tyrosinase inhibition 24.73%; L-DOPA oxidation suppression 14.29%). Cytotoxicity was negligible, maintaining >94% HDFn viability at 100 μg/mL, while TNF-α expression decreased by up to 14.7%.Conclusion: These findings suggest that leaf extracts are suitable for antioxidant and anti-inflammatory applications, whereas root extracts show promise as inhibitors of melanogenesis-related enzymatic steps. Overall, <i>C. sonchifolium</i> exhibits considerable potential as a natural functional resource.