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

Abstract 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 the roots of Phyllanthus glaucus . Their structures were elucidated by extensive spectroscopic data analyses and single-crystal X-ray diffraction. Phyllanglins A–C were unusual cleistanthane diterpenoids with phenylacetylene moieties, and a plausible biogenetic pathway was proposed to discuss the origins of them. All of the isolates were evaluated for their anti-inflammatory activities.