New triterpene glucosides, oligoporins A–C, from Oligoporus tephroleucus protect DNA from Fenton reaction

New triterpene glucosides, oligoporins A (1), B (2), and C (3), were isolated from the methanolic extract of the fruiting bodies of Oligoporus tephroleucus (Polyporaceae). Their structures were established by spectroscopic methods. These compounds significantly exhibited protective effect to plasmid DNA damage by hydroxyl radical (•OH) generated from the Fenton reaction with hydrogen peroxide and ferrous.