Three new guaiane-type sesquiterpenoids and a monoterpenoid from Merr.

Three undescribed guaiane-type sesquiterpenes (), and a monoterpenoid () along with eleven known compounds () were isolated from the crude extract of Merr. The structures of all the isolated compounds were extensively elucidated on the basis of comprehensive spectroscopic techniques (HRESIMS, 1 D NMR, and 2 D NMR). Their relative and absolute configurations were comprehensively established by NOESY spectroscopy, circular dichroism (ECD) and the calculated ECD analysis. All the isolates were tested for anti-inflammatory activity by measuring the amount of nitric oxide production. Amongst tested compounds, compounds exhibited moderate inhibitory activities against the production of nitric oxide with IC value of 35.5, 32.1, 46.7 M in RAW264.7 cells stimulated by LPS, respectively.