摘要：Ginsenosides have been regarded as the main active components of Panax ginseng C. A. M EYER , and the antioxidant activity of ginsenosides in vivo is well described. However, there has been virtually no report describing the direct free radical-scavenging activities of ginsenosides through the long history of ginseng research. The hydroxyl radical (·OH)-scavenging activity test using an electron spin resonance spectrometer (ESR) is suggested to be the most appropriate to measure the antioxidant activities of ginsenosides. Therefore, we investigated the ·OH-scavenging and ferrous metal ion-chelating activities of several ginsenosides of Panax ginseng using ESR for the identification of active ginsenosides and its structure and activity relationships. As a result, 20( S )-Rg3 showed the strongest activity, and the next were in the decreasing order of Rb1, Rg1, Rc, Rb2, and Rd when dissolved with water. The ·OH-scavenging activities of ginsenosides were related to the ferrous metal ion-chelating activities of their aglycone, 20( S )-protopanaxadiol. In addition, the ferrous metal ion-chelating activities of ginsenosides were thought to be influenced by their types of hydrophilic sugar moieties.
