Sesquiterpenoids from Pilea aquarum subsp. brevicornuta

Four new sesquiterpenoids named pileaterpenes A-D (1–4), together with three known sesquiterpenoids (5–7), were isolated from Pilea aquarum subsp. brevicornuta. The chemical structures of the new compounds were tentatively established by extensive spectroscopic methods and quantum chemical calculations. The absolute configurations of 1–3 were further determined by X-ray crystal diffraction, the modified Mosher’s method or ECD calculation method. All isolates but 7 were evaluated their activities against interleukin-8 (IL-8) production in HT-29 cells induced by IL-1β. [Display omitted] •Two new humulene-type sesquiterpenoids (pileaterpenes A and B, i.e. 1 and 2), an unusual secoaromadendrane derivative (pileaterpene C, 3), a new guaiane-type sesquiterpene (pileaterpene D, 4) as well as three known sesquiterpenoids were identified from Pilea aquarum subsp. brevicornuta.•The absolute configurations of the compounds 1–3 were successfully determined by X-ray crystal diffraction, chemical transformation or ECD calculation method.•Compound 3 represents the first example of naturally occurring 9,10-secoaromadendrane.•Moreover, compounds 3 and 4 were proved to be promising inhibitors against interleukin-8 (IL-8) production induced by IL-1β in HT-29 cells.