About 40 different types of ginsenoside (ginseng saponin), a major pharmacological component of ginseng, have been identified along with their physiological activities. Among these, compound K has been reported to prevent the development of and the metastasis of cancer by blocking the formation of tumors and suppressing the invasion of cancerous cells. In this study, ginsenoside Rb1 was converted into compound K via interaction with the enzyme secreted by -glucosidase active bacteria,

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... c citreum LH1, extracted from kimchi. The optimum time for the conversion of Rb1 to compound K was about 72 hrs at a constant pH of 6.0 and an optimum temperature of about 30°C. Under optimal conditions, ginsenoside Rb1 was decomposed and converted into compound K by 72 hrs postreaction (99%). Both TLC and HPLC were used to analyze the enzymatic reaction. Ginsenoside Rb1 was consecutively converted to ginsenoside Rd, F2, and compound K via the hydrolyses of 20-C -(1 6)-glucoside, 3-C -(1 2)glucoside, and 3-C -glucose of ginsenoside Rb1. Quan, L.H. et al. Bioconversion of ginsenoside by L. citreum tumorigenesis of chromosomes and suppressing the invasion of cancer cells. Moreover, it exhibits excellent cancer treatment effects similar to those of BI6-BL6, HepG2, K562, and 95-D (25,35). The oral absorption of major saponins is poor; extremely small amounts of Rb1 and Rb2 are oxygenated by gastric juices, with only limited components being soluble (12). In this regard, the biological usage rates of Rb1, Rb2, and Rg1 are 0.1-44%, 3.7%, and 1.9%-18.4%, respectively, which indicates that the majority of these saponins are excreted in the urine (28, 29, 32) . To enhance its pharmaceutical efficacy,