Antiproliferative activity of triterpenoids from Eclipta prostrata on hepatic stellate cells

Hepatic stellate cells (HSCs) have been known to play a key role in the pathogenesis of liver fibrosis. In the course of screening antifibrotic activity of natural products employing HSC-T6, a rat hepatic stellate cell line as an in vitro assay system, the methanolic extract of aerial parts of Eclipta prostrata L. showed significant inhibitory activity on HSCs proliferation. Activity-guided fractionation led to the isolation of five oleanane-type triterpenoids, echinocystic acid (1), eclalbasaponin II (2), eclalbasaponin V (3), eclalbasaponin I (4) and eclalbasaponin III (5), which are all echinocystic acid derivatives. Among the five echinocystic acid derivatives isolated, echinocystic acid (1) and eclalbasaponin II (2) significantly inhibited the proliferation of HSCs in dose- and time-dependent manners. Our present study also suggests the importance of free carboxylic acid at C-28 position in echinocystic acid derivatives for the antifibrotic activity. Taken together, antifibrotic activity of E. prostrata and its triterpenoids might suggest the therapeutic potentials against liver fibrosis.