Chemical constituents from the submerged plant Potamogeton crispus and.. their effects on NAD（P）H：quinone oxidoreductase 1

A new isopimarane-type diterpene （liwariverol, 1） and eight known compounds were isolated and characterized from the EtOAc extract of the whole plant of Potamogeton crispus. The structure of 1 was elucidated to be 17-hydroxy-8c~H-isopimara-9（11）,15- diene by means of spectroscopic methods. Among the isolates, crenulatoside A （2）, an acyclic sesquiterpene glycoside, was found to have anti-oxidative activity with enhancement of the expression of the NAD（P）H：quinone oxidoreductase 1 （NQO1） in human neuroblastoma SH-SY5Y cells at 100 μmol/L after a 24-h incubation.