Quantification of sesquiterpenlactones from leaves of Calea urticifolia (Asteraceae) during 2012

Abstract

Quantification of sesquiterpene lactones present in dried leaves of Calea unticifolia “Juanislama” was systematically carried out for the whole year 2012. Leaves samples were recollected bimonthly, and the sesquiterpene lactones were extracted utilizing the Soxhlet method with chloroform as solvent. The identification of the secondary metabolites was performed by thin-layer chromatography using the Baljet reagent and by UV/Vis spectroscopy utilizing chemical markers. The concentration of total sesquiterpene lactones, expressed as Juanislamine, found in the dried chloroform extract ranged from 39.58 to 90.02%. It was observed that the time periods from February 2 to April 15, from July 18 to July 31, and from August 30 to September 17 displayed the best yields, being the sampling on February 15 the one that led to the highest yield at an outstanding 90.02%. Regarding the percentage of total sesquiterpene lactones in the dried vegetal material, this ranged from 2.84% to 8.06% in the study. Likewise, the best time periods for such percentage fell from March 15 to April 15, and from August 30 to September 17, distinguishing the sample taken on March 30, which yielded a maximum of 8.06% of sesquiterpene lactones in the dried material.