Abstract
Phytochemical investigation of the MeOH extract of twigs and leaves of Baeckea frutescens led to the isolation of seven new polymethylated phloroglucinol meroterpenoids (PPMs), named baeckfrutones M-S (1-7). Their structures and absolute configurations were determined by spectroscopic analyses, chiral-phase HPLC analysis, and electronic circular dichroism (ECD) calculations. PPM 1 is a novel meroterpenoid possessing a 6/6/5/3 tetracyclic skeleton in PPMs, whereas 3 and 4 are the first hydroxytasmanone type phloroglucinol-monoterpene hybrids. (+)-2 and 7 displayed potent anti-inflammatory activity with IC(50) values of 20.86 ± 0.60 and 36.21 ± 1.18 μΜ, respectively.