Inhibition of Macrophage Superoxide Production by Two Prenylated Flavanones fromErythrina sigmoidea Hua

Abstract
Two prenylated flavanones namely sigmoidin A (SA) and sigmoidin B (SB) have been extracted from Erythrina sigmoidea Hua, a plant of Cameroon traditionally used in local medicine. An antioxidant activity was found and ascribed either to a direct reaction with O2 or to a direct and/or indirect action on the membrane-bound enzyme NADPH oxidase. The formation of stable radicals was also demonstrated by electron spin resonance spectroscopy (ESR) and related to the antioxidant activity.