Dichloromethane

BA and UA were provided by the Laboratory of Phytochemistry and Organic Synthesis -Federal University of Rio Grande do Sul, Brazil. BA and UA were obtained from Platanus acerifolia bark (2.0% yield) and industrial residue of apple peel Malus domestica (2.8% yield), respectively. Butyric anhydride, dimethylaminopyridine, pyridine and cyclohexane (≥99.0%, ≥99.0%, ≥99.0% and 99.5%) used in the semisynthesis of 3-OBB and 3-OBU acids were obtained from Sigma-Aldrich (Germany). Dichloromethane (99.5%) were purchased from VETEC (Rio de Janeiro, Brazil). Silica gel 60 and Silica gel 60 F254 TLC plates used during the purification of the compounds were purchased from Merck (Germany). Acetonitrile (HPLC grade) and formic acid (98%) were purchased from Merck (Germany). Purified water was produced by a Milli-Q system (Millipore Corp., MA, USA).

Essential oil (EO) was extracted from the leaves of E. urograndis. These leaves were separated into four groups: young leaves without damage, young leaves with damage, mature leaves without damage, and mature leaves with damage. All leaves were damaged moments before the oil was extracted. Initially, the moisture content of each group of leaves was measurement by the gravimetric method using an infrared moisture determination balance (Quimis, model Kett FD-600). The method was done with 1.0 g of leaves at a temperature of 105±5 °C for 15 min.
The extraction of the EO from each group of leaves was carried out in a Clevenger apparatus, by hydrodistillation, under reflux for 4 hours with 50 g of fresh leaves (Silva et al., 2020) (link). The extraction was carried out in triplicate.
The EO was extracted from water with dichloromethane (Vetec, RJ, Brazil) (3 x 10 mL). The solvent was removed by evaporation in a heating plate at 35 °C. Essential oils obtained were stored in glass bottles, sealed, and kept in a refrigerated environment in the absence of light.