Essential oil composition and antioxidant capacity of Lippia schomburgkiana

The leaves and fine stems of Lippia schomburgkiana recorded an essential yield of 1.8%, the main constituents of which were 1,8-cineole (64.1%) and alpha-terpineol (12.0%). The methanol extract of L. schomburgkiana inhibited the DPPH radical, resulting in an EC50 value of 16.1 +/- 0.7 microg x mL(-1), which is only three times lower than that of trolox (4.7 +/- 0.4 microg x mL(-1)), signifying a high antioxidant activity for the species. The amount of total phenolics (376.7 +/- 35.5 mg GAE/g) and the trolox equivalent antioxidant capacity (327.0 +/- 24.8 mg TE/g) of the methanol extract confirmed the significant antioxidative capacity of this plant. The brine shrimp bioassay carried out on the oil (49.6 +/- 0.4 microg x mL(-1)) showed high toxicity, providing important evidence of its biological activity. The sensory evaluation of the leaves of L. schomburgkiana showed a percentage acceptance value very close to commercial oregano, indicating that the plant can be used in spice and condiment products.