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-8αH-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.