Free radical scavenging capacity as related to antioxidant activity and ginsenoside composition of Asian and North American ginseng extracts

Different Panax species; derived from Asia (Panax ginseng C.A. Meyer) and North America (Panax quinquefolium L.) were extracted by methanol and evaluated for relative ginsenoside composition and antioxidant activities. Ginseng root contained a greater proportion of total ginsenoside compared to ginseng hair analyzed by high-performance liquid chromatography.; North American ginseng root was characterized with undetectable ginsenoside Rf and greater Rb-1/Rb-2 than Asian ginseng root. Panax quinquefolium exhibited a relatively higher (P < 0.05) affinity to scavenge free radical than panax ginseng using the 2,2-azobis (3-ethylbenzothine-6-thine-6-surfonic acid) radical model. In a bilayer lamella suspension oxidation model induced by peroxyl radicals, ginseng samples exhibited notable antioxidant activity. Specifically, however, the P. quinquefolium extracts delayed lipid peroxidation longer (P < 0.05) than the P. ginseng extracts. Ginseng extracts from both Panax species protected human low-density lipoprotein against cupric ion-mediated oxidation. Similar protection was observed against peroxyl radical-induced supercoiled DNA breakage. A pure ginsenoside standard (e.g., Rb-1) produced similar results. The antioxidant activities of different ginseng species and specific plant parts include free radical scavenging and may be related to ginsenoside Rb-1/Rb-2 content.