Antioxidant capacity and toxicological evaluation of pterospartum tridentatum flower extracts

Pterospartum tridentatum Willk. (prickled broom) is an autochthonous plant, common in Portuguese territory. The yellow flowers are used in traditional medicine, as a potential cure for all body illnesses, mainly for throat irritation treatment or for diabetes, hypertension and hypercholesterolemia therapy.Despite its traditional use, no toxicological assessment has been performed as we know. A high antioxidant activity of P. tridentatum flower water extract was acessed in good agreement with its ESI-MS spectrum that revealed the presence of several flavonoids, as luteolin-O-(O-acetyl)-glucuronide, luteolin-O- glucuronide or isorhamnetin-O-hexoside. Mitocondrial respiratory rates (state 4, state 3 and FCCP-stimulated respiration) and respiratory indexes (respiratory control and P/O ratios) showed no consistent decrease of respiratory and phosphorylative efficiencies for the concentrations tested (up to 500 μg.mL-1). Cytotoxicity evaluation, using MTT assay, was reliable with the previous results. In conclusion, for the concentration range commonly used P. tridentatum flowers usage can be regarded as harmless and trustworthy