This study compares the antioxidant properties and phytochemical profiles of three pairs of widely used medicinal plant species to their counterparts from Provence, France: Arnica montana with Pentanema montanum (formerly known as Inula montana), Helichrysum italicum with Helichrysum stoechas, and Satureja hortensis with Satureja montana. Phytochemical composition has been investigated using UHPLC-HRMS/MS and molecular networking, revealing chemical profiles dominated by phenylpropanoids and flavonoids, with lignans, sesquiterpene lactones or polyketides aside. Well-plate DPPH/ABTS assays allowed to evaluate antioxidant activity of extracts and post-column assays to identify antioxidant compounds. The three Provence species demonstrated comparable or superior antioxidant activities than their counterparts, primarily attributed to phenolic compounds such as mono- and di-caffeoylquinic acids, quercetagetin-7-O-glucoside and myricetin acetylhexoside. These findings show the potential of Provence species to be substituted to some overharvested medicinal plants. This research supports biodiversity conservation while promoting the integration of these local species into pharmaceutical, nutraceutical, cosmetic, and food industries.