LAUSR

Abstract Dengue virus infection is a neglected disease prevalent in most tropical and subtropical areas. Currently there is no any antiviral drug indicated for the routine treatment of dengue patients. As part of our ongoing search for potential anti-dengue virus agents we have investigated the methanol extract of Faramea bahiensis (Rubiaceae) leaves. This species is endemic in Brazil, and there are no reports on its chemical composition or therapeutic potential. Its crude MeOH extract showed in vitro non-cytotoxicity and anti-dengue virus serotype 2 (DENV-2) activity in human hepatocarcinoma cell lineage (HepG2). A marked reduction on viral load (100%) was observed. Sequential fractionation of the bioactive crude extract led to the isolation of a bioactive new flavanone glycoside: 5-hydroxy-4′-methoxy-flavanone-7- O -s- d -apiofuranosyl-(1 → 6)-s- d -glucopyranoside, the known 5,4′-dihydroxy-flavanone-7- O -s- d -apiofuranosyl-(1 → 6)-s- d -glucopyranoside and a diateroisomeric epimer pair of the known 5,3′,5′-trihydroxy-flavanone-7- O -s- d -glucopyranoside. The treatment of DENV-2 infected HepG2 cells with the new flavanone was able to control viral replication promoting a reduction of the number of infected cells (12%), together with a decrease of infectious particles in the culture supernatant (97%) and of the number of RNA copies of DENV-2 in HepG2 cells (67%). Structural determinations were made by NMR techniques in one and two dimensions ( 1 H NMR, 13 C NMR, COSY, HSQC and HMBC), HRMS, UV, OR and CD.