Three New Diterpenoids From Phyllanthus emblica Roots: Structure and Anti-HIV Activity

Three undescribed aromatic diterpenoids (1-3), were isolated from the roots of Phyllanthus emblica and structurally characterized. Compounds 1 and 2 are cleistanthane-type diterpenoids, and the latter possesses a rare 4,5-seco-20(10→5)-abeo-ent-cleistanthane scaffold with an acetenyl at C-14. Compound 3 was elucidated as a new podocarpane trinorditerpenoid. The structural elucidation, including absolute configuration determination, was achieved through comprehensive spectroscopic analysis (nuclear magnetic resonance, mass spectrometry, ultraviolet, and infrared) combined with time-dependent density functional theory-based electronic circular dichroism calculations. Compound 2 showed potential activity against HIV-1_Bal PsV infection with an IC₅₀ value of 3.30 µM.