New ent-Kaurane and cleistanthane diterpenoids with potential cytotoxicity from Phyllanthus acidus (L.) Skeels

Six diterpenoids including three ent-kauranes (1-2, 4) and three cleistanthanes (3, 5-6) were isolated from the roots and stems of Phyllanthus acidus (L.) Skeels. Of them, (165)-ent-16,17,18-tri-hydroxy-19-nor-kaur-4-en-3-one (1), phyllanthone A (2), and 6-hydroxycleistanthol (3) are new compounds, while the ent-kaurane diterpenoids were reported from the titled plant for the first time. Their structures were elucidated on the basis of the extensive spectroscopic analyses. Compounds 2 and 4-6 displayed cytotoxic potential with IC50 values ranging from 1.96 to 29.15 mu M. They also showed moderate anti-inflammatory activities (IC50 = 6.30-12.05 mu M). Particularly, the new ent-kaurane 2 displayed cytotoxic potential against HL-60 (IC50 = 2.00 mu M) and MCF-7 (IC50 = 3.55 mu M) cells, and anti-inflammatory activity (IC50 = 6.47 mu M).

Automated summary

Six diterpenoids, including three newly discovered compounds, were isolated from Phyllanthus acidus. These compounds exhibited cytotoxic and anti-inflammatory activities.