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.