Secondary Metabolites of Mansonia gagei and Their Potential Anti-dengue Properties.

Three undescribed compounds, including compounds 1 and 2 with a bicyclo[3.2.1]octane skeleton, along with a coumarin derivative (compound 3) and seven known compounds (4-10), were isolated from the heartwood of Mansonia gagei. To our knowledge, compounds 6-8 are reported for the first time from the Mansonia genus. The structures of these compounds were determined through high-resolution electrospray ionization mass spectrometry, nuclear magnetic resonance spectroscopic analysis, and density functional theory calculations. The antiviral activity of isolated compounds was assessed against dengue virus serotype DENV1, indicating that compound 2 exhibited potent anti-dengue activity with a 50% Plaque Reduction Neutralization Test value of 17.47 µM.