RESUMEN
ABSTRACT Calea urticifolia (Mill.) DC., Asteraceae, is a native plant of the Yucatan Peninsula used in traditional medicine to treat inflammation and pain. The bioassay-guided purification of the ethanol root extract allowed the isolation of the main bioactive metabolites, which were identified as an inseparable mixture of thymol (1) and 3-methyl-4-isopropylphenol (2), together with 3,4-O-dicaffeoylquinic acid methyl ester (3), 3,4-O-dicaffeoyl-epi-quinic acid methyl ester (4), 3,5-O-dicaffeoyl-epi-quinic acid methyl ester (5) and 3,5-O-dicaffeoylquinic acid (6). The results showed that the analgesic activity detected in the root extract of C. urticifolia could be attributed mainly to the mixture of 1 and 2 and to the novel 3,4-O-dicaffeoyl-epi-quinic acid methyl ester (4). Alternatively, the similarity on the antiinflammatory and antioxidant activities of the dicaffeoylquinic acid derivatives 3-5 suggests that the former might be related to their ability as radical scavengers.
RESUMEN
The bioassay-guided purification of the ethanol extracts of Acmella pilosa and Cnidoscolus souzae, two plants of the native flora of the Yucatan Peninsula used in traditional medicine to treat inflammation and pain, resulted in the identification of rosmarinic acid (1) and caffeic acid (2) as the bioactive metabolites from A. pilosa, and of 7-deoxynimbidiol (4) as the major bioactive metabolite from C. souzae. Metabolites 1, 2, and 4 proved to be responsible for the antioxidant activity originally detected in the corresponding organic crude extracts; 7-deoxynimbidiol (4) showed good analgesic and anti-inflammatory activities, inhibiting the pain induced by PGE2 and reducing the edema induced by carrageenan, respectively.
