Effects of Hepatoprotective Compounds from the Leaves of Lumnitzera racemosa on Acetaminophen-Induced Liver Damage in Vitro

Phytochemical investigation of the n-BuOH fraction of the mangrove plant Lumnitzera racemosa WILLD. (Combretaceae) led to the isolation of one new flavonoid glycoside; myrcetin 3-0-methyl glucuronate (1), one new phenolic glycoside; lumniracemoside (2) and one new aliphatic alcohol glycoside; n-hexanol 1-0-rutinoside (3), in addition to seven known compounds (4-10). The structures of these compounds were determined by spectroscopic analyses (UV, IR, high resolution-electrospray ionization (HR-ESI)-MS, one-and two-dimensional (1D- and 2D)-NMR). Compound 7 showed the highest hepatoprotective activity against acetaminophen-induced hepatotoxicity using human HepG2 cells at protection % value of 34.2 +/- 3.1%, while compounds 1, 2, 3, 6, and 9 showed weak to moderate hepatoprotective activity (11.6-18.9%). Almost all of these compounds showed stronger 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity compared with the standard Trolox. These results suggest the usefulness of this plant extract and the isolated compounds as promising hepatoprotective agents.