Germacrane Sesquiterpene Dilactones from and Their Antibacterial and Cytotoxic Activity.

Four new germacrane sesquiterpene dilactones, 2-hydroxyl-11,13-dihydrodeoxymikanolide (), 3-hydroxyl-11,13-dihydrodeoxymikanolide (), 1,3-dihydroxy-4,9-germacradiene-12,8:15,6-diolide (), and (11,13-dihydrodeoxymikanolide-13-yl)-adenine (), together with five known ones (-) were isolated from the aerial parts of . Their structures were elucidated on the basis of extensive spectroscopic analysis. Compound is featured with an adenine moiety in the molecule, which is the first nitrogen-containing sesquiterpenoid so far isolated from this plant species. These compounds were evaluated for their in vitro antibacterial activity against four Gram-(+) bacteria of (), methicillin-resistant (), () and (), and three Gram-(-) bacteria of (), (), and (). Compounds and - were found to show strong in vitro antibacterial activity toward all the tested bacteria with the MIC values ranging from 1.56 to 12.5 µg/mL. Notably, compounds and showed significant antibacterial activity against the drug-resistant bacterium of with MIC value 6.25 µg/mL, which was close to reference compound vancomycin (MIC 3.125 µg/mL). Compounds and - were further revealed to show in vitro cytotoxic activity toward human tumor A549, HepG2, MCF-7, and HeLa cell lines, with IC values ranging from 8.97 to 27.39 μM. No antibacterial and cytotoxic activity were displayed for the other compounds. The present research provided new data to support that is rich in structurally diverse bioactive compounds worthy of further development for pharmaceutical applications and for crop protection in agricultural fields.