Guajadials C-F, four unusual meroterpenoids from Psidium guajava

Guajadials C-F (1–4), four sesquiterpenoid-based meroterpenoids with unprecedented skeletons were isolated from the leaves of Psidium guajava. Their structures and relative configurations were established by extensive spectroscopic analysis. A possible biosynthetic pathway for 1–4 was also proposed. Graphical abstract Electronic Supplementary Material Supplementary material is available for this article at 10.1007/s13659-012-0102-4 and is accessible for authorized users.