In vivo antimalarial activity of ginseng extracts.

CONTEXT Novel antimalarial agents are in demand due to the emergence of multidrug resistant strains. Ginseng, a medicinal plant with antiparasitic activity, contains components that can be used to treat the tropical disease malaria. OBJECTIVE Ginsenosides and polysaccharides are active components of ginseng. This study aimed to elucidate the ability of these compounds to inhibit the replication of Plasmodium yoelii in an attempt to determine whether the medicinal uses of ginseng are supported by pharmacological effects. New antimalarial compounds may be developed from ginsenosides and water-soluble ginseng polysaccharides (WGP). MATERIALS AND METHODS Ginsenosides and ginseng polysaccharides were prepared from ginseng. Antimalarial activities were examined by 4-day tests and repository tests. Macrophage phagocytosis was tested in normal and malaria-bearing mice. RESULTS Ginseng polysaccharides could inhibit residual malaria infection. After a 6-day treatment, the parasitemia reductions of WGP and acidic ginseng polysaccharide (WGPA) were 55.66% and 64.73% at 200 mg/kg/day, respectively. Ginsenosides showed significant antimalarial activity on early infection. Protopanaxadiol-type ginsenosides caused 70.97% chemosuppression at 50 mg/kg/day, higher than 52.8% of total ginsenosides at the same dose. DISCUSSION AND CONCLUSION Protopanaxadiol-type ginsenosides have remarkably suppressive activity during early infection, while acidic ginseng polysaccharides have significant prophylactic activity against malaria by stimulating the immune system. We propose that the activity of ginsenosides is dependent upon non-specific carbohydrate interactions and that the activity of ginseng polysaccharides is due to immunological modulation. Ginsenosides and ginseng polysaccharides might have a potential application in antimalarial treatments.