Optimization of medicinal plant extraction methods and their encapsulation through extrusion technology

In this study, aqueous extracts of Plectranthus ecklonii, Plectranthus grandidentatus, Plectranthus ornatus, Plectranthus porcatus, and Plectranthus saccatus were prepared using infusion, decoction, microwave and ultrasonic methods. Rosmarinic and caffeic acids were their major components while chlorogenic acid was for the first time found in a Lamiaceae extract (P. saccatus), being the acetylcholinesterase (AChE) inhibition and the antioxidant activities furthermore evaluated. P. ecklonii microwave extract with a high yield (22.9 ± 0.3 mg of dry plant extract/mL), the best AChE inhibition activity (59.14 ± 4.97%) and a strong antioxidant activity (25.47 ± 1.1%) at 1 mg/mL, was then successfully encapsulated into alginate beads (98.64-100.0%). The high rosmarinic and caffeic acids content as well the high AChE inhibition and antioxidant properties after the encapsulation strongly indicate that this strategy could potentiate the action of the plant extract by promoting a protective effect and a sustained release of active constituents and, ultimately, improve their pharmacological effects.