However, 20(S)-Rh1 reached its maximum at 4 h and decreased gradually, possibly by further dehydration at C-20 position to yield Rh4 or Rk3. The content of Rh4 was gradually increased even after 12 h ( Fig. 5). Quantitative results are summarized in Table 1. Two unknown

peaks were identified in HPLC chromatogram (Fig. 3). The contents of these unknown peaks were calculated by comparing their ELSD responses to those of MR2 and Rb1, respectively, as ELSD response is almost Veliparib proportional to the amount of analyte. The total content of saponin in VG prior to steaming was 212.4 mg/g, which decreased to 144.2 mg/g after 20 h steaming (Table 1). Fig. 6 summarizes the change in antiproliferative activity of processed VG on A549 lung cancer cell line. The antiproliferative effect was rapidly increased upon steaming and reached its maximum at 12 h. It is noteworthy that the antiproliferative activity seems to have a close relationship with the sum of the content of PPD-type less polar ginsenosides Rg3, Rg5, and Rk1 (Fig. 7), which is in accordance with the report that these less polar ginsenosides have stronger antiproliferative activity than their polar analogs [13], [19], [22] and [23]. Even though antiproliferative activity and the content of PPD-type less polar ginsenoside

seem to have a close relationship, there might be other unknown factors that affect the activity as the curves of 0.5 mg/mL in Figs. 6, 7 are not all the Selleckchem CH5424802 same. PPT-type less polar ginsenosides Rh1, Rk3, and Decitabine cost Rk4 were also increased by steaming; however, they have little antiproliferative effect [23]. Concentration of 3 mg/mL was too high for the test of antiproliferative activity as raw sample itself inhibited cell proliferation by 70% as shown in Fig. 6. DPPH radical scavenging activity, by contrast, continuously increased until 20 h (Fig. 8). This can be attributed by the fact that two activities are arisen from different

chemical constituents. Antiproliferative activity arises from ginsenosides whereas radical scavenging activity is arisen mainly from phenolic compounds and Maillard reaction products [24]. Steaming of Vietnamese ginseng at 120°C changed its saponin constituents and biological activities remarkably. Polar PPD and PPT ginsenosides transformed to their less polar analogs rapidly, whereas ocotillol saponins were stable upon steaming process. Antioxidant and antiproliferative activities are greatly increased by steaming. It seems that the antiproliferative activity of processed VG is closely related to the content of ginsenoside Rg3, Rg5, and Rk1. All contributing authors declare no conflicts of interest. This work was supported by the grant from the Ministry of Education, Science, and Technology of Korea (No. 2012048796), Rural Development Administration of Korea (No. PJ008202022013), and Ministry of Science and Technology of The Socialist Republic of Vietnam (No.