Phenylacetylene-bearing 3,4-seco-cleistanthane diterpenoids from the roots of Phyllanthus glaucus

Three new cleistanthane diterpenoids, phyllanglins A-C (1-3), a new natural product, 4-acetyl-bergenin (4), and three known compounds (5-7) were isolated from acetone extract of the roots of Phyllanthus glaucus. Their structures were elucidated by extensive spectroscopic data analyses and single-crystal X-ray diffraction. Phyllanglins A-C are cleistanthane diterpenoids with phenylacetylene moieties, and phyllanglin C features an unusual seven-membered lactone ring. All of the isolates were evaluated for their anti-inflammatory activities.168