Clinical significance of redox effects of Kampo formulae, a traditional Japanese herbal medicine: Comprehensive estimation of multiple antioxida tive activities

Abstract

To clarify the clinical significance of the redoxcontrolling effects of Kampo, a traditional Japanese herbal medicine, we determined the scavenging activities of various reactive oxygen species in clini cally used Kampo formulae using an electron spin resonancebased technique. Formulae containing Rhei Rhizoma (i.e., mashiningan and daiobotanpito) showed high scavenging activity against the alkoxyl radical, and crude extract quantity was significantly corre lated with scavenging activity. Hydroxyl radical scavenging activity was positively correlated with the quantity of Zingiberis Rhizoma. Strong hydroxyl radical scavenging activity was also found in formulae containing both Bupleuri Radix and Scutellariae Radix, a widely used antiinflammatory combination. Formulae containing a clinically common combination of Scutellariae Radix, Coptidis Rhizoma, and Phellodendri Cortex induced high superoxide scavenging activity. Singlet oxygen scavenging activity was high in formulae containing Bupleuri Radix and Glycyrrhizae Radix. In contrast, formulae containing Rehmanniae Radix showed generally low reactive oxygen species scavenging activities, and the quantity of Rehmanniae Radix was negatively correlated with hydroxyl radical and singlet oxygen scavenging activities. These results indicate that the antioxidative effects of Kampo formulae are not uniform but complexly varied against multiple reactive oxygen species. Some formulae have almost no antioxidant effects but may act as prooxidants.