Composição química e avaliação antimalárica in vitro de Xylopia amazonica R. E. Fries (Annonaceae)

Abstract

The emergence of Plasmodium strains resistant to antimalarials commonly used has motivated the search for new antimalarial drugs. Natural products isolated from Amazonian plants and their semi-synthetic derivatives have been shown to be promising sources of antimalarial compounds. Several plants of the genus Xylopia (family Annonaceae) are used by folk medicine for the treatment of malaria and its symptoms. The genus presents a great variety of chemical compounds with important pharmacological properties, emphasizing alkaloids, terpenes and acetogenins. The present work has the objective of discovering new antimalarials through analysis of the chemical composition and evaluation of the antimalarial activity of Xylopia amazonica RE Fries, starting from previous studies carried out by the Laboratory of Active Principles of the Amazon (LAPAAM) Antimalarial activity in crude extracts. For the accomplishment of the work, fine branches and leaves of X. amazonica were collected in the Adolpho Ducke Forest Reserve. The thin branches and leaves were taken to LAPAAM / INPA, where they were weighed, dried and ground in a knife mill. Afterwards, extractions were carried out by means of maceration using ultrasound and solvents in order of increasing polarity, in addition to acid-base extraction to obtain extracts rich in alkaloids. The extracts obtained from in vitro antimalarial tests performed at the Malaria and Dengue Laboratory of the National Research Institute of the Amazon were submitted. Finally, chromatographic techniques were applied to the extracts considered active for the isolation and / or purification of fractions and / or substances and spectroscopic techniques for the identification or structural elucidation of the active substances. Using high performance liquid chromatography (HPLC) two active substances (nornantenin and anonaine) were isolated against chloroquine resistant P. falciparum K1 strains with IC50 of 5.23 g / mL and 4.8 g / mL, respectively.