From the fruits of the tropical tree Aphanamixis grandifolia , six new evodulone-type (ring A-seco ) limonoids aphanalides I-N (1 -6 ), three new protolimonoids polystanins E-G (7 -9 ), and three chain-like diterpenoids nemoralisins A-C (10 – 12 ), along with nine known compounds were isolated, whose structures were elucidated
on the basis of extensive spectroscopic analysis. The limonoids varied mainly in ring
D: a cyclopentenone ring for aphanalides I (1 ) and K (3 ), an oxetane ring between C-7 and C-14 for aphanalides J (2 ) and L (4 ), and a 14, 15-oxirane ring for aphanalides M (5 ) and N (6 ). Polystanin E (7 ) was an apo-tirucallane triterpenoid bearing a six-membered hemiketal at the side-chain,
and polystanins F (8 ) and G (9 ) were two new tirucallane triterpenoids. Nemoralisins A-C (10 – 12 ) were three bicyclo-diterpenoids rarely found in meliaceae. The absolute configurations
were determined by combination of single crystal X-ray diffraction analyses, CD exciton
chirality method, Mosher's method and calculated electronic circular dichroism (ECD).
The initial insect antifeedant activity to compounds 1 -6 were evaluated, and compound 6 exhibited the most potential to such activity.
