ESTUDO QUÍMICO DAS FOLHAS E GALHOS DE UM ESPÉCIME DE Nectandra hihua (LAURACEAE) E AVALIAÇÃO DO SEU POTENCIAL BIOLÓGICO

Abstract

Chemical and biological studies carried out with species of MS flora, especially the genus Nectandra of the Lauraceae family, show a variety of classes of secondary metabolites with different chemical structures, with the ability to act against different pathologies. This genus is notably known for the presence of sesquiterpenes, alkaloids and, mainly, neolignans, which are recognized for having a diverse range of skeletons due to their biosynthesis and for having different biological activities, such as antitumor and antibacterial. Despite this, only 25% of Nectandra species have been studied chemically. Thus, the present work aimed to expand the knowledge about the chemical composition and biological potential of the leaves and branches of the Nectandra hihua species. By this means, a specimen was collected in Campo Grande-MS, the leaves and branches being submitted separately to extraction with 95% ethanol and the partition with organic solventes following, resulting in the corresponding hexane, AcOEt and hydromethanolic phases. The hexane and AcOEt phases of the leaves and branches were submitted to different chromatographic processes, such as adsorption, exclusion and high performance liquid chromatography, aiming at the isolation and purification of the compounds. The structural elucidation of the isolated substances was carried out through the techniques of one- and two-dimensional NMR, IV and HPLC-DAD-MS/MS. To evaluate the biological potential of extracts and phases of N. hihua, anti-T. cruzi, antimicrobial, antitumor (leukemia and melanoma) and genotoxic. As a result, the chemical study of leaves and branches issued in the identification of 20 substances, being two sesquiterpenes, alismol and spathulenol, a triterpene, presqualene, three flavonoids, epicatechin, catechin and isocampheride, two phenolic amides, N-trans-feruloyltyramine and N -cis-feruloyltyramine, 3 lignoids reported in the literature, dehydrodieugenol, dehydrodieugenol B and Miliusin F, 3 unpublished lignoids, 1-allyl-3-[3'-methoxy-1'-(8',9'-dihydroxy-propyl)- phenoxy]-4-hydroxy-5-methoxybenzene, (1-allyl-3-[3'-methoxy-1'-(9'-chlorine-8'-hydroxy-propyl)-phenoxy]-4-hydroxy-5- methoxybenzene) and 3-(4-allyl-2-methoxyphenoxy)-4-hydroxy-5-methoxybenzaldehyde, classified as a dinor-neolignan, a class reported for the first time in Nectandra, in addition to sitosterol, sitosterol-3-O-β- D-glucopyranoside, sitosterol-3-O-β-D-glucopyranosyl-esterified at C-6' with fatty acid, α-tocopherol, phytol and a polyprenol. Regarding the biological potential, the hexane phases showed the best anti-T. cruzi, antibacterial and against leukemic cells. In the genotoxic evaluation, the extracts showed mutagenicity for the offspring of the cross with high bioactivation (HB). One of the compounds isolated, dehydrodieugenol B, showed moderate activity against Staphylococcus aureus. In view of the results found, the specimen of N. hihua has significant antitumor potential against leukemic cells, it shows to be a rich natural source of a substance with antimicrobial potential, dehydrodieugenol B (~1 g isolated), produces a class of metabolites of rare occurrence in plants, the dinor-neolignans, and still reveals the first related chlorinated neolignans in the literature.

Key-words: Neolignan; dinor-neolignan; antitumoral; chlorine derivative.