Euphorbia diterpenoids possess inhibitory
effects
of Kv1.3 ion channel, but most of this research has focused on diterpenoids
with jatrophane-related or ingenane-related skeletons. In the present
study, nine undescribed (1–9) and
16 known (10–25) diterpenoids, based
on jatrophane, lathyrane, ingenane, abietane, and atisane skeletons,
were identified from the methanol extract of the aerial parts of Euphorbia fischeriana. The structures were established by
analysis of the spectroscopic data as well as by single-crystal X-ray
diffraction analysis. Among the isolated diterpenoids, macrocyclic
jatrophanes and lathyranes exerted Kv1.3 blocking activity. Compound 8 exhibited good selectivity on the inhibition of the Kv 1.3
channel rather than hERG channel, with a selectivity index over 7.0.
The selective activity of lathyrane diterpenoids indicates that macrocyclic
diterpenoids have the potential to be further investigated as therapeutic
agents for the treatment of autoimmune diseases.