Estudo químico monitorado pelas atividades larvicida antibacteriana e anti-inflamatória de duas espécies de bignoniaceae (Tabebuia elliptica (A. DC.) Sandwith e T. roseo-alba Ridl.)

Abstract

This work shows chemical study monitored by antinociceptive, anti-inflammatory, antimicrobial and larvicidal activities of two Bignoniaceae species [Tabebuia elliptica (A. DC.) Sandwith and T. roseo-alba Ridl.]. After drying at room temperature and grinding, the material from stem barks, stems and leaves of both species were extracted by maceration with methanol and/or acetone. After removal of the solvents under vacuum, crude extracts were suspended in methanol and water solution and successively extracted with hexane, chloroform and ethyl acetate. The fractions resulting from this procedure were evaluated in writhing model induced by acetic acid and exhibited a significant reduction of nociceptive response. Chemical studies of some fractions from these extracts of T. roseo-alba resulted in the isolation and identification by NMR technique of two neolignans [Icariside E4 and (7R, 8S) - dihydrodehydrodiconiferyl alcohol], a benzoic acid derivative (p-methoxibenzoic acid), a misture of two triterpenes (ursolic and oleanolic acids) and a phytosteroid (sitostenone); while from T. elliptica fractions resulted in the isolation of a chlorinated iridoid (rehmaglutin D), a phenylpropanoid (coumaric acid) and a phytosteroid (β-sitosterol). In pharmacological tests, Icariside E4 showed a peripheral antinociceptive effect, involving potassium channel ATP-K+ and coumaric acid significantly reduced levels of total leukocytes, neutrophils, as well as the percentage of ROS-producing cells in acute lung inflammation model induced by LPS showing an anti-inflammatory potential. Extracts from stems and leaves of both species showed antimicrobial activities against strains of S. aureus and E. faecalis and in the larvicidal assays, although the crude extracts of the barks, stems and leaves have exhibited low mortality at 250 ppm, hexane and chloroform fractions from barks and stems of T. roseo-alba and ethyl acetate from stems of T. elliptica, showed high mortality percentages. Substances, Icariside E4 and (7R, 8S) - dihydrodehydrodiconiferyl alcohol, are being described for the first time in the genus Tabebuia and the isolation of the chlorinated iridoid, Rehmaglutina D, in this work can aid in positioning the Tabebuia genus in the Bignoniaceae family.