Phthalide mono- and dimers from the rhizomes of Angelica sinensis and their anti-inflammatory activities

Abstract Three pairs of enantiomeric phthalide dimers, including two new ones, angesicolides A ( 1 ) and B ( 2 ), and a new phthalide monomer ( 3 ), were obtained from the rhizomes of Angelica sinensis . Their structures were established through spectroscopic methods, quantum calculations, and chiral HPLC analysis. Compounds 1 and 2 were [2 + 2] and [4 + 2] cycloadducts of phthalide monomers, and their hypothetical biogenetic origin was proposed. Compounds 2 , (+)- 2 , (−)- 2 , 4 , (+)- 4 , and (−)- 4 exhibited significant inhibitory activity against NO production with IC 50 values range from 1.23 to 5.55 μM. Graphical Abstract