In the Provence region (France), an Asteraceae species named Pentanema montanumm (L.) D.Gut.Larr., Santos-Vicente, Anderb., E.Rico & M.M.Mart.Ort. (syn. Inula montana L.) is traditionally used with the same indications as Arnica montana L., against bruises, wounds, rheumatisms and muscular pain, and is even locally called “Arnica de Provence” (Garayev et al., 2018; Gyawali et al., 2022). Both species contain mainly sesquiterpene lactones and phenolic compounds, which are usually implicated in the defence against oxidative stress, involved in acute or chronic diseases (Vuolo et al., 2019). Hydro-ethanolic extracts of these two species underwent evaluation of antioxidant potential and phytochemical studies. The radical scavenging activity was assessed using both 96 well-plate DPPH and DPPH-On-Line-HPLC assays. Well-plate DPPH assay showed higher activity for P. montanum extracts, with an IC50 twice lower than A. montana extracts, respectively 23.66 ± 0.75 µg/mL and 45.71 ± 3.05 µg/mL. DPPH-On-Line-HPLC assay allowed to identify 1,5-dicaffeoylquinic acid as the main compound responsible for the anti-oxidant activity in both extracts. This compound is more abundant in P. montanum extracts, supporting the well-plate DPPH assay results. Metabolomic data were obtained through UHPLC-HRMS/MS analysis and processed using computational metabolomics and MS-based Molecular Networking. The two species only share 16% of their chemical composition, most metabolites being species-specific. This presentation will emphasize the comparative analysis by molecular networking of A. montana and P. montanum chemical profiles, with a focus on exclusive metabolites of each species and those contributing to radical scavenging activity.