SIMULTANEOUS DETECTION AND CHARACTERIZATION OF METABOLITES FROM MIKANIA LINDLEYANA DC (ASTERACEAE) LEAVES USING ESI-LC-MS

The tea from leaves of Mikania lindleyana DC. (Asteraceae), popularly known as “sucuriju” or “sucurijuzinho”, native in the Amazon region [1], is the main popular form of use of the plant to treat gastritis and inflammation [2]. 100 g of dried and minced herbal material were used to obtain the herbal preparation by decoction in 1 L of water, by boiling for 15 minutes. After cooling, the extract was filtered and frozen at -45 °C and lyophilized. Lyophilized aqueous extract (AEML) was fractionated aiming the isolation of chemical substances for characterizing this plant species. The fractionation was performed on Sephadex LH-20 (25 × 500 mm) using EtOH/H2O (1:1 v/v) as eluent and flow 2 mL/min to give 33 fractions that were further analysed (TLC, LC-DAD-MS). For HPLC-MS analysis, MeOH/H2O (1:1 v/v) solutions of AEML and fractions were prepared at a final concentration of 3 mg/mL and 1 mg/mL, respectively, and centrifuged before injection. Each reference standard was quantitatively weighed, dissolved in methanol, separately, at a concentration of 1.0 mg/mL and the stock solutions obtained stored under refrigeration (-20 °C). The working solutions prepared from the stock solutions are adjusted to a concentration of 500 µg/mL of each standard substance. Identification of constituents was performed by LC-DAD based on their UV-spectra and full scan MS-spectra, registered in the negative and positive modes. The signals [M-H]- and [2 M-H]- as well as the masses of the fragments obtained permit propose 13 substances, namely phenolic acids, nucleotides, derivatives of catechin and one amino acid. Constituents were quantified using a calibration curve drawn with external standard.