Five selective 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) competitive inhibitors, hupehenols A–E (1–5), were isolated from Viburnum hupehense. The structure elucidation indicated that compounds 1–5 are new 20,21,22,23,24,25,26,27-octanordammarane triterpenoids. Their structures were established on the basis of NMR spectroscopic and mass spectrometric analysis. Hupehenols A–E (1–5) showed inhibition against human 11β-HSD1, with hupehenols B (2) and E (5) having IC50 values of 15.3 and 34.0 nM, respectively. Moreover, hupehenols C (3) and D (4) are highly selective inhibitors of human 11β-HSD1 when compared to murine 11β-HSD1.

Vibsatins A (1) and B (2), a pair of 14,15,16,17-tetranorvibsane-type diterpenoids that feature a bicyclo[4.2.1]nonane moiety formed by a new C-13/C-2 bond, were isolated from the twigs and leaves of Viburnum tinus cv. variegatus. The structures and absolute configurations were elucidated by a combination of NMR spectra, optical rotation, and X-ray diffraction experiments. A possible biogenetic pathway is also proposed. Moreover, vibsatin A (1) enhanced the neurite outgrowth of NGF-mediated PC12 cells at a concentration of 10 μM.

Lycospidine A (1), the first example of a Lycopodium alkaloid which contains an unprecedented five-membered A ring, was isolated from Lycopodium complanatum. The unique five-membered A ring in 1 indicates that carbons 2–5 in 1 are presumably derived from proline instead of the lysine biosynthetically, which suggests that 1 represent a new class of Lycopodium alkaloid. In addition, the unique structural feature and biosynthetic origin of 1 shed new insight into the structural diversity of Lycopodium alkaloid analogue libraries potentially accessible by engineered biosynthesis.