Background: Plant extracts are sources of valuable compounds with biological activity, especially for the antiproliferative\nactivity against pathogens or tumor cells. Myricetin is a flavonoid found in several plants that has been\ndescribed as an inhibitor of Human immunodeficiency virus type 1 (HIV-1) through its action against the HIV reverse\ntranscriptase, but myricetin derivatives have not been fully studied. The aim of this study was to evaluate the anti-\nHIV-1 activity of glycosylated metabolites obtained from Marcetia taxifolia and derived from myricetin: myricetin\nrhamnoside and myricetin 3-(6-rhamnosylgalactoside).\nMethods: Compounds were obtained from organic extracts by maceration of aerial parts of M. taxifolia. All biological\nassays were performed in the MT4 cell line. Antiviral activity was measured as inhibition of p24 and reverse transcriptase\nwith a fluorescent assay.\nResults: Both flavonoids have antiviral activity in vitro, with an EC50 of 120 �¼M for myricetin 3-rhamnoside (MR) and\n45 �¼M for myricetin 3-(6-rhamnosylgalactoside) (MRG), both significantly lower than the EC50 of myricetin (230 �¼M).\nAlthough both compounds inhibited the reverse transcriptase activity, with an IC50 of 10.6 �¼M for MR and 13.8 �¼M for\nMRG, myricetin was the most potent, with an IC50 of 7.6 �¼M, and an inhibition greater than 80%. Molecular docking\napproach showed correlation between the free energy of binding with the assays of enzyme inhibition.\nConclusions: The results suggest that glycosylated moiety might enhance the anti-HIV-1 activity of myricetin, probably\nby favoring the internalization of the flavonoid into the cell. The inhibition of the HIV-1 reverse transcriptase is\nlikely responsible for the antiviral activity.
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