Preparation of ginsenosides Rg3, Rk1, and Rg5-selectively enriched ginsengs by a simple steaming process

In this study, the red ginseng-specific bioactive ginsenosides Rg3, Rk1, and Rg5 were selectively enriched in ginseng prepared using a steaming and drying process. To achieve a selective increase in ginsenoside Rg3, Rk1, and Rg5 content, white ginsengs were steamed in a hermetically sealed container at 98 °C for 30 h, dried, and then further processed by steaming for another 30–45 h, and dried once more. The ginsenoside content of the resultant ginseng was analyzed using high-performance liquid chromatography with an evaporative light scattering detector. In steamed ginsengs, polar ginsenosides, such as Rb1, Rb2, Rc, and Rg1, were not present or could only be detected in negligible amounts, whereas ginsenosides 20(S)-Rg3, 20(R)-Rg3, Rk1, and Rg5 were newly generated; their dry weight contents were up to 23.98, 15.01, 11.36, and 17.56 mg/g, respectively, in 75 h (30 + 45 h) steaming condition. These results indicate that the preparation method developed in the present study can selectively increase the content of the ginsenosides Rg3, Rk1, and Rg5, and therefore would be very useful for selective preparation of red ginseng-specific minor ginsenosides.