Bioactive constituents from the rhizomes of Atractylodes macrocephala

Twelve undescribed compounds including five sesquiterpenes (1-5), one monoterpene (6), and four lignans (7a/7b and 8a/8b), along with two other types (9 and 10) were isolated from the rhizomes of Atractylodes macrocephala. Among them, two pairs of enantiomers (7a/7b and 8a/8b) were successfully separated by chiral-phase HPLC, while racemate 9 could not be resolved. Their structures and absolute configurations were unambiguously elucidated by spectroscopic data analysis and electronic circular dichroism (ECD) calculations. Notably, compounds 1 and 2 are rare sesquiterpene hybrids featuring an eudesmanolactam linked to a resorcinol or methyl 2-methylpentanoat through a CN bond. Compound 3 represents the first example of eudesmanolide sesquiterpene with an oxygen-bridge between C-8 and C-14. Compounds 7a and 7b are a pair of rare enantiomeric benzodioxane norneolignans. Additionally, compound 2 exhibited weak cytotoxicity against SGC-7901 cells. Compound 4 significantly promoted the proliferation of LPS-induced IEC-6 cells with the rate of 117.2%.