Polystanins A-D, four new protolimonoids from the fruits of Aphanamixis polystachya.

ABSTRACT

Two new apo-tirucallane triterpenoids with six-membered hemiketal, polystanins A (1) and B (2), and two new tirucallane triterpenoids, polystanins C (3) and D (4) were isolated from the fruits of Aphanamixis polystachya. They were elucidated on the basis of detailed spectroscopic analysis including IR, high resolution-electrospray ionization (HR-ESI)-MS, 1 dimensional (1D)- and 2D-NMR. Their absolute configurations were determined by a combination of modified Mosher's method, and electronic circular dichroism (ECD) calculation.