Antiviral Activity of Faramea hyacinthina and Faramea truncata Leaves on Dengue Virus Type-2 and Their Major Compounds

The defatted fractions of the Faramea hyacinthina and F.truncata (Rubiaceae) leaf MeOH extracts showed invitro non-cytotoxic and anti-dengue virus serotype 2 (DENV2) activity in human hepatocarcinoma cell lineage (HepG2). Submitting these fractions to the developed RP-SPE method allowed isolating the antiviral flavanone (2S)-isosakuranetin-7-O--d-apiofuranosyl-(16)--d-glucopyranoside (1) from both species and yielded less active sub-fractions. The new diastereoisomeric epimer pair (2S)+(2R) of 5,3,5-trihydroxyflavanone-7-O--d-apiofuranosyl-(16)--d-glucopyranoside (2a/2b) from F.hyacinthina; the known narigenin-7-O--d-apiofuranosyl-(16)--d-glucopyranoside (3) from both species; rutin (4) and quercetin-4--d-O-glucopyranosyl-3-O-rutinoside (5) from F.hyacinthina, and kaempferol-3-O-rutinoside (6), erythroxyloside A (7) and asperuloside (8) from F.truncata have been isolated from these sub-fractions. Compounds 4-8 are reported for the first time in Faramea spp.