Antitrypanosomal triterpenoid with an ε-lactone E-ring from Salvia urmiensis.

Mahdi Moridi Farimani, Samad Nejad Ebrahimi, Peyman Salehi, Mir Babak Bahadori, Ali Sonboli, Hamid Reza Khavasi, Stefanie Zimmermann, Marcel Kaiser, Matthias Hamburger

Index: J. Nat. Prod. 76(9) , 1806-9, (2013)

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Abstract

A new triterpenoid, urmiensolide (1), was isolated from Salvia urmiensis. The structure was elucidated by a combination of 1D and 2D NMR, HRESIMS, and X-ray crystallographic analyses. The absolute configuration was established by comparison of experimental and simulated ECD spectra. Urmiensolide is the first pentacyclic triterpenoid bearing a ε-lactone E-ring. The compound showed in vitro antitrypanosoal activity with an IC₅₀ value of 5.6 μM against the Trypanosoma brucei rhodesiense STIB 900 strain and a selectivity index of 33. A possible biosynthetic pathway of 1 from α-amyrin is proposed.