Sucupiranins A-L, Furanocassane Diterpenoids from the Seeds of Bowdichia virgilioides.

Twelve new furanocassane diterpenoids, sucupiranins A-L (1-12), and three known compounds (13-15) were isolated from the seeds of Bowdichia virgilioides. The structures of the compounds were elucidated via 1H and 13C NMR analysis, including 2D NMR (1H-1H COSY, HSQC, HMBC, and NOESY); HRMS data; and X-ray crystallographic analysis. The absolute configurations were defined using their electronic circular dichroism (ECD) spectra by applying the exciton chirality method to the bis-p-bromobenzoate of compound 13. Sucupiranin J (10) inhibited lipopolysaccharide-induced nitric oxide production (IC50 30.6 μM), whereas sucupiranins J (10), K (11), and 13 exhibited weak antimalarial activity against Plasmodium falciparum K1 with IC50 values of 32.2, 23.5, and 22.9 μM and selectivity indices of 4.3, 1.9, and >12.0 (MRC-5/K1), respectively.