Antioxidant action of natural health products and Chinese herbs

The scavenging effects of reactive oxygen species (ROS) by two natural health products, antioxidant analogs (AOA), and green magma (GM), and 16 medical Chinese herbs were investigated in two in vitro ROS-generating systems, activated neutrophils and xanthine-xanthine oxidase. Native, unheated AOA and GM products significantly reduced ROS levels, while unheated Chinese herbs had a negligible effect on ROS levels. In contrast, heat-extracted Chinese herbs and AOA markedly, and GM mildly, suppressed the levels of ROS in both systems. The ROS scavenging activity of these native, unheated products was unaffected by dialysis, but that of heated products was markedly diminished by dialysis. Further, the incubation of these products with gastric juice obtained by a gastric tube from healthy volunteers revealed results comparable to those induced by heat treatment with or without dialysis. Although the antioxidant activity of these natural products appears to be partly due to enzymes such as superoxide dismutase (SOD), the predominant factor seems to be low-molecular-weight ROS scavengers that are liberated or activated by gastric juice digestion as observed after heat treatment.