Manure application enhances the biomass production, phytochemical contents, antioxidant, and essential oil of Lippia dulcis

ABSTRACT Lippia dulcis is a medicinal species used by communities in the Amazon region for the control of diabetes and as a tranquilizer. The objective of this study was to evaluate the plant biomass production, antioxidant defense, and chemical profiles of the phenolic compounds and essential oil of plants grown under different doses of cattle, quail, and chicken manure. Chicken and quail manure at a dose of 6 kg m-2 reached the highest values of dry weight and essential oil yield of the leaves and positively influenced bisabolol production. Cattle manure affected the content and yield of the essential oil of the inflorescences, the antioxidant defense performance, and the chemical composition of phenolic compounds and essential oil. Plants grown with cattle manure showed a linear increase in the amounts of these substances with increasing dose. Chicken and quail manure led to the highest values of these components at doses between 0 and 3 kg m-2. The evaluation of phenolic compounds and antioxidant defense showed the highest values at doses of 0, 1.5, and 3 kg m-2, regardless of the manure used. The essential oil concentration was higher in the inflorescences, and its total yield was higher in the leaves. The chemical composition varied between these vegetative organs.