Bioactive components of Mexican oregano oil as affected by moisture and plant maturity

The effect of moisture and plant growth on Mexican oregano (Lippia graveolens HBK) essential oil composition was examined in field trials. Essential oil content of dry oregano leaves was about 2% (w/w). Thymol and carvacrol were the major components in the oil fraction and plant maturity had a significant effect on oil composition. However, moisture effect and plant growth phase/moisture interaction were not significant. Examination of the oil composition of samples collected from three cultivated and one wild oregano type indicated that the oil obtained from wild plants contained significantly lower amount of 1,8-cineole and carvacrol than the cultivated types. The thymol content of the wild variety was higher.