All the plants used in the study were collected in the Department of Santander, Colombia. The material was identified up
to the species level, and the exsiccatae were deposited in the
National Herbarium (Table 1). The extraction of the essential
oils, as well as the chemical composition thereof, was carried
out based on the protocol reported by Stashenko et al. The essential oils were obtained by simple hydrodistillation
(HD) and microwave-assisted hydrodistillation (MWHD).
HD was conducted in a round-bottomed flask (5 L) with
500 g of plant material and 4 L of water using an electric
heater (boiling water) for 2 h. The oil was decanted from the
condensate, previously saturated with NaCl, and dried with
anhydrous sodium sulfate. For MWHD, the hydrodistillation
unit was placed in a domestic microwave oven
(2.45 GHz, 800 W) with a hole on the side through
which an external glass condenser was connected to the
round-bottomed flask containing the plant material
(500 g) and water (0.2 L) inside the oven. The unit
was operated for 30 min at maximum power, which
caused the water to boil vigorously, maintaining the reflux
thereof. The EO was accumulated in a Dean-Stark trap and
was later decanted from the condensate and dried with anhy drous sodium sulfate.