Steaming process has been shown to change chemical compositions of Vietnamese ginseng (VG) Panax vietnamensis by reducing the content of polar ginsenosides, such as ginsenosides-Rb., -Rc, -Rd, -Re, and -Rg1, but increasing the content of less polar ginsenosides. This continuing work aimed to isolate and demonstrate newly formed saponins in Vietnamese ginseng aftcr steaming process. As a result, seven dammarane-type triterpenoid saponins were isolated and structurally elucidated by spectroscopic analyses including MS and NMR. For the first time, newly formed ginsenoside-Rk. and ginsenoside-Rgs were found in processed VG. In addition, 5 ocotillol saponins were isolated with a simple method from processed VG.Tác giả sử dụng khái niệm giới hạn Banach để chứng minh một số khẳng định trong lý thuyết các phương trình sai phân tuyến tính, đưa ra một số ví dụ áp dụng các khẳng định này