Chemical Composition and DPPH free Radical Scavenging Activity of Tithonia diversifolia

Tithonia diversifolia (Hemsl.) A. Gray (Asteraceae) is a plant widely distributed in tropical regions. Although used traditionally in several countries for sprains (Mexico), jaundice (China), and liver protection (Taiwan), in Vietnam it is primarily utilized as green manure due to its high phosphorus, calcium, and magnesium content. This study aimed to characterize the chemical constituents and evaluate the antioxidant potential, via DPPH free radical scavenging, of ethanol leaf extracts of T. diversifolia collected in Buon Ma Thuot, Dak Lak Province, Vietnam. Chemical profiling was performed using liquid chromatography–mass spectrometry (LC–MS). Antioxidant activity was assessed by the DPPH assay, with ascorbic acid serving as a positive control. LC–MS analysis identified sesquiterpenes and phenolic compounds as the major chemical classes in the ethanol extract. The extract exhibited moderate DPPH scavenging activity, with an IC₅₀ value of 38.85 mg/mL, compared to 34.99 mg/mL for ascorbic acid. The ethanol extract of T. diversifolia leaves contains bioactive sesquiterpenes and phenolics with moderate free radical scavenging capacity, supporting its potential as a natural antioxidant source.