Comparative phytochemical profiling, antioxidant responses and preliminary NO-inhibition screening of urena lobata L. AERIAL part extracts across phenological stages and ethanol concentrations

This study compared nine Urena lobata L. aerial-part extracts from three phenological stages (April, June, August) and three ethanol concentrations (30%, 70%, 96%). Extracts were assessed for TPC, TFC, DPPH scavenging, reducing power, NO inhibition with cell viability, and dual-polarity LC-MS/MS. T1-96 (April, 96% ethanol) showed the highest TPC (632.6 ± 2.3 mg GAE/g) and TFC (621.0 ± 8.5 mg QE/g), and the lowest DPPH IC50 (66.9 ± 0.2 microg/mL) and reducing-power OD0.5 (575.1 ± 2.5 microg/mL). Higher TPC/TFC generally coincided with lower DPPH IC50 values, but this was interpreted descriptively. NO data were not used for potency ranking or IC50 estimation because concentration ranges differed and measurements were technical replicates. LC-MS/MS retained 34 negative-ion and 21 positive-ion putative features at MSI Levels 2–3. Findings remain preliminary because each stage represented one collection event at one site in one year.