Two new diterpenoids from the stems of Rhododendron dauricum as GABAA receptor agonists

Two new diterpenoids, dauricumins A (1) and B (2), together with two known aromatic meroterpenoids (3 and 4), were isolated from the petroleum ether soluble fraction of the stems from Rhododendron dauricum through an HPLC-MS-SPE-NMR combination strategy. The absolute configurations of 1 and 2 were elucidated by ECD calculations and [Rh-2 (OCOCF3)(4)]-induced CD spectrum analysis. In a membrane potential FLIPR assay, confluentin (4) showed an agonistic effect on GABA(A) receptor (EC50 = 20 mu M).

Automated summary

Two new diterpenoids, dauricumins A and B, along with two known aromatic meroterpenoids, were isolated from the stems of Rhododendron dauricum using HPLC-MS-SPE-NMR combination strategy. The absolute configurations of the new compounds were determined through ECD calculations and CD spectrum analysis. One of the compounds showed an agonistic effect on the GABA(A) receptor in a membrane potential FLIPR assay.