Phytochemical study of syn. aerial parts: sesquiterpene lactones with anti-protozoal activity.

Two new eudesmane-type sesquiterpene lactones, 1β,3α,8α-trihydroxy-11β,13-dihydroeudesma-4(15)-en-12,6α-olide () and 1β,4α,8α-trihydroxy-11β,13-dihydroeudesma-12,6α-olide (), and an unprecedented elemane-type sesquiterpene lactone, 1β,2β,8α-trihydroxy-11β,13-dihydroelema-12,6α-olide () along with a known eudesmanolide artapshin () were isolated from Structures were elucidated by NMR, HR-ESI-MS, and ECD spectral data analysis. The anti-protozoal activity was evaluated against promastigotes and amastigote-infected macrophages. They showed dose- and time-dependent activity against amastigotes with IC values in the range of 4.9 to 25.3 μM being favourably far below their toxicity against normal murine macrophages with CC values ranging from 432.5 to 620.7 μM after 48 h of treatment. Compound exhibited the strongest activity and the highest selectivity index (SI) with IC of 4.9 ± 0.6 μM and SI of 88.2 comparable with the standard drug, meglumine antimoniate (Glucantime), with IC and SI values of 15.5 ± 2.1 μM and 40.0, respectively.