IQUIMEFA   05518
INSTITUTO QUIMICA Y METABOLISMO DEL FARMACO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Isolation of a trypanocidal sesquiterpene lactone from Stevia gilliesii by chromatographic techniques
Autor/es:
ELSO O; CERNY N; MALCHIODI E; REDKO F; BIVONA A; SANCHEZ ALBERTI A; CATALAN C; SÜLSEN V; SELENER M; CAZORLA S; LOMBARDO E
Lugar:
Barcelona
Reunión:
Congreso; 10th World Congress on Pharmacology & 6th International Conference and Exhibition on Advances in Chromatography & HPLC Techniques; 2018
Resumen:
Chagas? desease is an illness caused by the protozoan Trypanosoma cruzi wich affects about 6 - 7 million people worldwide (1). Sesquiterpene lactones (STL) are a large group of secondary metabolites mostly found among Asteraceae family plants. Sesquiterpene lactones present a wide range of biological activities such as anti-inflammatory, cytotoxic, antiplasmodial and antitrypanosomal, among others.In a previous work, we have evaluated the effect of a group of STLs against T. cruzi epimastigotes and their citotoxicity against Vero cells. Eupahakonenin B (EKB), isolated from Stevia gilliesii var. gilliesii Hook. & Arn. (Asteraceae) has shown promising trypanocidal activity and selectivity index (IC50= 0.78 µM; CC50= 363.72 µM; SI= 466) (2). In this work we describe the isolation of EKB by chromatographic methods in order to assess its trypanocidal activity against infective and intracellular forms of T. cruzi.Dried aerial parts of S. gilliesii var. gilliesii were extracted twice with dichloromethane. Dichloromethane extract was partitioned between hexane and a water/ethanol mixture and fractionated by column chromatography using silicagel and dichloromethane/ethyl acetate (1:2) as mobile phase. Eluted fractions were analyzed by thin layer chromatography (sp: Silica gel 60 F254, mp: Dichloromethane/ethyl acetate 1:2). EKB containing fractions were joined and taken to dryness to obtain the compound as a greenish gum. EKB purity was analyzed by HPLC . The effect of EKB on bloodstream infective form of T. cruzi was assayed by counting remaining living parasites in a Neubauer chamber and the effect of EKB on intracellular forms of T. cruzi was assayed using β-galactosidase transfected parasites as previously described (3). The sesquiterpene lactone EKB appeared as a blue spot on TLC after spraying the plate with anisaldehyde sulphuric acid (Figure 2). The STL was purified and isolated by chromatographic techniques (96% purity) and identified by spectroscopic methods (Figure 2). This STL showed activity and selectivity on trypomastigote (IC50 = 30 µM; SI= 11) and amastigote (IC50 = 29.9 µM; SI= 12) forms of T. cruzi. The mechanism of action of EKB and its in vivo activity will be evaluated.