Fig. 1. (A) Isolation profiles of stigmastsrol from Navicula incerta extract, (B) Structure of stigmasterol isolated from Navicula incerta. (C) Cell viability of HepG2 cells treated with stigmasterol for 24 h. Cells were cultured in serum-free media. After that HepG2 cells were treated with different concentrations (5, 10, 20 uM) of stigmasterol for 24 h and cell viability was assessed by the MTT assay. ^a-cDifferent letters on each bar indicates significant difference (P ＜ 0.05) according to Duncan’s multiple range test.