Evaluation In Vitro of Plant Essential Oils as Natural Antioxidants

Abstract

ABSTRACT Five essential oils, geranium, monarda, nutmeg, oregano and thyme, were evaluated for their antioxidant properties at final concentrations of 0.75 ppm to 100 ppm. Thiobarbituric acid reactive substances (TBARS) were measured in three avian assay systems based on egg yolk, one-day old chicken livers and muscle from mature chickens. All the oils demonstrated extensive antioxidant capacities. The egg yolk TBARS assay showed monarda, nutmeg and thyme essential oils to be the most effective while the chick liver assay revealed nutmeg oil to be the most active. The chicken muscle assay demonstrated equal activity for the oils of monarda, nutmeg, oregano and thyme. Based on this assay technique, oils demonstrating the most effective antioxidant capacities will be chosen for feeding trials to demonstrate their effectiveness in vivo upon polyunsaturated fatty acid (PUFA) metabolism during vital periods of the lifespan, in particular, the foetal/neonate and aging periods.