Antioxidant effects of Agastache mexicana extracts: an in vitro approach

Agastache mexicana (Kunth) Lint & Epling (toronjil) is a medicinal plant distributed in the Michoacan state in Mexico and used in traditional medicine for gastrointestinal disorders, anxiety, cardiovascular alterations and efficiently as an anti‐inflammatory and analgesic among others. Ethnobotanical, pharmacological and phytochemical studies have been carry out, however there are currently no scientific relevance studies that support their therapeutic properties. Toronjil have mainly volatile oils (camphene, β‐pinene, limonene, 1,8‐cineole, furfural, citronellal, menthol and pulegone) into their chemical composition, all of them knows as antioxidants. Notwithstanding, there are not reports about the effects of toronjil over the oxidative stress, either in vivo and/or in vitro assays. By this reason, the main aim of this work is to evaluate in vitro the antioxidant properties of Agastache mexicana and some of their isolated compounds. Hydroalcoholic, methanolic and hexanic (Soxhlet) extracts were obtained from toronjil aerial parts and different concentrations (0.001, 0.01, 0.1 and 1 mg ml−1) were tested using the DPPH, ABTS and TBARS methods to evaluate the antioxidant capacity. Our results indicated that the methanol extract (since the 0.1 mg ml−1) has the capacity to scavenger or inhibit the free radicals tested with any assay mentioned here (DPPH, ~93%; ABTS, ~99% and TBARS, ~94%); our GC‐MS analysis reveals the presence of limonene, linalool, mentone, α‐terpineol, pulegone and eugenol mainly. Only eugenol is a potent scavenger of free radicals because its remove ~94%, ~98% and ~98% using the DPPH, ABTS and TBARS methods respectively. The rest of the compounds tested have a relatively low capacity to remove free radicals by either method assayed.