Chemical constituents from Centaurothamnus maximus and their antimicrobial activity.

A new sesquiterpene lactone, 3β,10α-dihydroxy-10β-(hydroxymethyl)-8α-(4-hydroxymethacrylate)-1α,5α,6β7α-guai-4(15), 11(13)-dien-6,12-olide (), along with twenty-one known compounds, were identified from the aerial parts of . The structures of the isolated compounds were elucidated on the basis of spectroscopic evidences and correlated with known compounds. Compounds (, , and ) were identified from for the first time. Antibacterial and antifungal activities of the isolated compounds were tested using the agar disc diffusion method. Compounds that demonstrated promising antimicrobial activity were evaluated for their minimum inhibitory concentration (MIC). The results showed that compounds and were the most effective antibacterial compounds against ATCC 6633, ATCC 25923 and ATCC 27736, with MIC estimates between 8 and 32 mg/mL. In addition, compound exhibited the strongest antifungal activity against ATCC 14243 and ATCC 14243 with MIC 8 mg/mL.