Estudo químico e biológico de Warszewiczia schwackei (Rubiaceae)

Abstract

In Brazil, especially in the Amazon region, there is a great biodiversity of plant species that have not yet been studied chemically or biologically, including spe cies of the family Rubiaceae, which is recognized mainly for the production of a wide variety of alkaloids of pharmacological importance. In this sense, the aim of work is the isolation and chemical characterization of substances of the species Warszewiczi a schwackei , as well as the evaluation of the biological activities of the extracts. To evaluate the biological activities the following were used: DPPH and Fe 3+ p henant h roline tests (to determine the antioxidant activity); microdilution in broth using the REMA (Resarzuri n Microtitre Assay) method (for determination of activity against pan sensitive Mycobacterium tuberculosis strain H37Rv); the multi resistant P. falciparum strain K1 (for determination of antimalarial activity); the microcrustacean Artemia salina and macrophagic cells J774 A.1 (to assess toxicity); the in vivo test on the chorioallantoic membrane of chicken embryos (to assess angiogenic activity). The fractionation of the hexane extract of the leaves allowed for the isolation of  sitosterol and squalene, and from the me thanolic extract of the leaves 3 indole alkaloids were obtained: tryptamine, tetrahydroharman and ochrolifuanin e , as well as a flavonoid: catechin. The methanolic extracts of both leaves and branches showed antioxi dant capacity against DPPH and Fe 3+ p henant h roline and after biological evaluation of the extracts showed moderate activity against M. tuberculosis , and in the antimalarial trial also showed activity against P. falciparum . When tested against A. salina , it was possible to observe that all the extracts were toxic at the concentration of 1000  g/mL. The dose dependent antiangiogenic potential of all W. schwackei extracts was observed and tryptamine exhibited 40% inhibition of blood vessel grouth at 1  g/mL. The results showed the biological potential of the W. schwackei and encourage the contin uation of the fractionation to isolate other substances and evaluate them in the same tests in which the extracts were active in order to determine if the substances are responsible for the biological activities.