Extraction of essential oil from Aloysia citriodora Palau leaves using continuous and pulsed ultrasound: Kinetics, antioxidant activity and antimicrobial properties

[Display omitted] •Essential oil extraction from A. citriodora using continuous and pulsed ultrasound.•Ultrasound pretreatments brought about higher yields, shorter time.•Recovery of components in pulsed ultrasound was higher than continuous mode.•Ultrasonic pretreatment increased antibacterial and antioxidant activities.•Ultrasonication pretreatment may release more metals into essential oil. The impact of continuous and pulsed ultrasound pre-treatments (15, 30 and 45min) followed by conventional hydrodistillation on the characteristics of extracted essential oils (EOs) from dried leaves of Aloysia citriodora Palau was evaluated for the first time. Chemical composition of EOs, antibacterial and antioxidant activities, as well as the contents in heavy metals (iron, copper, lead, arsenic, and cadmium) were determined. Pretreating the leaves with ultrasound (continuous and pulsed), before hydrodistillation, resulted in shorter extraction time (93.81–121.16min) and higher extraction yields (2.8 (v/w) %) (p