Biol. Pharm. Bull. 30(11) 2126—2134 (2007)

used as a representative tonic for two thousand years in the Far East countries like Korea, China, and Japan. Now, ginseng is one of the most famous and precious herbal medicines consumed around the world. Although ginseng exhibits multiple pharmacological actions in vitro or in vivo studies, its mechanisms on various efficacies are still elusive. Recent accumulating evidences show that ginseng saponins (or ginsenosides) are the main active ingredients of ginseng (Fig. 1). Ginseng root contains 3—4% of ginseng saponins. Ginseng saponins are especially abundant in fine roots rather than main body of ginseng root. Ginseng saponins are one of glycoside saponins and one of the derivatives of triterpenoid dammarane consisting of thirty carbon atoms. Each ginsenoside has a common hydrophobic four ring cholesterol-like backbone structure with sugar moieties attached. About 30 different types of ginseng saponins have been isolated and identified from the root of Panax ginseng (Fig. 1). Caenorhabditis elegans (C. elegans) is one of nematode species and is one of free living animals under the earth rather than is parasitic in host animals or plants. C. elegans takes its food from dead animals or plants. Since C. elegans has short life cycle and large amounts of worms can be easily grown for biochemical assays or genetic studies in the laboratory, the organism is one of the well-established genetic models and its development processes have well characterized. Interestingly, C. elegans cannot synthesize sterols unlike other 2126 Vol. 30, No. 11