Encapsulation of yarrow essential oil in hydroxypropyl-beta-cyclodextrin: physiochemical characterization and evaluation of bio-efficacies

Essential oil from yarrow (Achillea millefolium L. s. l.) has a broad spectrum of pharmacological activities. However, active chemical components of yarrow oil are sensitive to environmental factors such as, light, oxygen and temperature. Encapsulation of essential oil offers solutions for the limitation. Yarrow oil was encapsulated in hydroxypropyl--cyclodextrin (HPCD) through freeze-drying technique with encapsulation efficiency of 45%. Inclusion complex formation was examined by scanning electron microscope, Fourier transformed infrared spectroscopy and UV-vis analysis and phase solubility study. Yarrow oil gave strong antioxidant activity of 72% DPPH scavenging at 50 g/mL. HPCD could protect active compounds of essential oil and retained antioxidant activity after sunlight exposure. Yarrow oil also exhibited antibacterial activity against Staphylococcus aureus and Escherichia coli with the minimum inhibitory concentration (MIC) values of 250 g/mL and 500 g/mL, respectively. The antibacterial efficacy was much improved after encapsulation against both S. aureus and E. coli with the MIC value of 62.5g/mL. RESUMENEl aceite esencial de la milenrama (Achillea millefolium L. s. l.) presenta un amplio espectro de actividades farmacologicas. Sin embargo, los componentes quimicos activos del aceite son sensibles a factores ambientales tales como, luz, oxigeno y temperatura. La encapsulacion del aceite esencial ofrece soluciones para esta limitacion. El aceite se encapsulo en hidroxipropil--ciclodextrina (HPCD) mediante la tecnica de liofilizacion con un rendimiento del 45%. La formacion del complejo de inclusion se analizo mediante tecnicas de SEM, FT-IR y UV-vis y se realizo un estudio de solubilidad. El aceite presento una fuerte actividad antioxidante de 72% de DPPH. HPCD protege los compuestos activos de aceite esencial y retoene la actividad antioxidante despues de la exposicion a luz solar. El aceite tambien exhibio actividad antibacteriana contra Staphylococcus aureus y Escherichia coli con valores minimos de concentracion inhibitoria (MIC) de 250 g/mL y 500 g/mL, respectivamente. La eficacia antibacteriana mejoro mucho despues de la encapsulacion contra S. aureus y E. coli con un valor de CIM de 62,5 g /ml.