*4.1. General*

Analytical-grade *n*-hexane, ethyl acetate (EtOAc), *n*-butanol (*n*-BuOH), ethanol (EtOH) and UPLC/MS-grade methanol (Sigma Aldrich, St. Luis, MO, USA) were used. HPLC-grade water was prepared using a Milli-Q purification system (Millipore, Burlington, MA, USA). The RP18 cartridge was a Phenomenex Strata C18-E. Sakuranetin and 7-methoxyaromadendrin (standards) were previously isolated from the leaves of *Ageratina havanensis* (Kunth) R. M. King & H. Robinson [17]. They were identified and standardized by spectroscopic techniques (1H-NMR, 13C-NMR, 2D NMR, MS). The stability was evaluated by NMR.
