Abstract

• The aim of the study is to identity a viral protein R (Vpr) inhibitor from the bioactive selected medicinal plants collected in Myanmar. Their methanol and chloroform extracts were tested separately for their inhibitory effect on Vpr activities on the TREx-HeLa-Vpr cells. The chloroform extracts of P. javanica wood, G. sherwoodiana rhizomes, and K. candida roots and rhizomes showed the most potent anti-Vpr activities with cell proliferation percentages of 178%, 160%, and 160% at 10 µg/mL, respectively. Then, the thirty-nine compounds were isolated from these three bioactive samples, identified by UV, FT IR, NMR, HR-ESI-MS, and CD. Five new quassinoids (1-5), together with ten known compounds (6-15) were isolated from the active chloroform extract of the P. javanica wood. Isolated quassinoids 1-4, 6-9, and 10 displayed potent anti-Vpr activity, with the cell proliferation rate ranging from 148% to 181%, at the 5 µM concentration. Then, two new homodrimane type sesquiterpenoids (16 and 17), a new 16-norlabdane diterpenoid (18), two new naturally occurring compounds (19 and 20), together with eleven known compounds (21-31) were isolated from the chloroform extract of the G. sherwoodiana rhizomes. The isolated compounds 16, 18, 19, 23, 24, 27, and 29 showed moderate anti-Vpr activities at a concentration of 10 µM. In addition, three new compounds (32-34), together with five known compounds (35-39) were isolated from the chloroform extract of the K. candida roots and rhizomes. All of the isolated compounds showed moderate anti-Vpr activities on the TREx-HeLa-Vpr cells. Among the isolated compounds, 32 and 34-38 possessed higher anti-Vpr activity than 33 and 39.