POLYPHENOLIC COMPOUNDS ANALYSIS AND ANTIOXIDANT ACTIVITY OF TWO ROMANIAN CULTIVATED AGASTACHE SPECIES

Abstract

Agastache species are aromatic plants native in America and Asia, used empirically for the treatment of gastrointestinal disorders and infections. Our study aimed to evaluate the polyphenolic profile and the in vitro antioxidant activity of two Agastache species (A. rugosa and A. foeniculum), recently introduced in culture in Romania. Spectrophotometric quantifications of the total polyphenols content (TPC), total flavonoids content (TFC), total caffeic acid derivatives content (TCADC) and LC-MS analysis were performed to identify and quantify the phenolic compounds. The antioxidant activity was investigated using DPPH and ferric reducing antioxidant power (FRAP) assays. Our results showed that A. rugosa extract had a higher content of total polyphenols (53.67 mg GAE/g dry weight, d.w.), flavonoids (9.37 mg RE/g dry weight, d.w.) and caffeic acid derivatives (42.6 mg CAE/g dry weight, d.w.) compared to A. foeniculum extract. Tilianin and rosmarinic acid were the main compounds of the two extracts (5038.48 μg/mL and 4608.3 μg/mL, respectively), determined in higher concentration in A. rugosa. The results of the phytochemical analysis were in agreement with the evaluated antioxidant activity, which was slightly better for A. rugosa (IC50 = 71.94 μg/mL for DPPH assay). To the best of our knowledge, this is the first report on the polyphenolic composition of Romanian cultivated A. rugosa and the identification of tilianin and rosmarinic acid, two natural compounds with important pharmaceutical potential.