Chemical constituents of the roots of Vietnamese Panax pseudoginseng

Abstract

Panax pseudoginseng is very precious national medicinal plant in Vietnam. Phytochemical study on the methanol extract of the roots of this plant led to the isolation of ten dammarane‐type triterpene glycosides including (20S)‐sanchirhinoside (1), 6‐O‐(β‐D‐glucopyranosyl)‐20‐O‐(β‐D‐xylopyranosyl)‐3β,6α,12β,20(S)‐tetrahydroxydrammar‐24‐ene (2), chikusetsusaponin L5 (3), notoginsenoside R1 (4), ginsenoside Re (5), ginsenoside Rb1 (6), ginsenoside F2 (7), ginsenoside Rd (8), ginsenoside F1 (9), and ginsenoside Rg1 (10). Their structures identified by HR‐ESI‐MS, 1D and 2D NMR data in comparison with the reported data. All the isolates showed significant inhibitory effects on NO production in the LPS stimulated RAW 264.7 cells with the IC₅₀ values ranging from 21.04±2.21 to 32.21±2.12 μM, compared to a value of 9.80±0.78 μM for the positive control compound, N^G‐monomethyl‐L‐arginine (L‐NMMA). In addition, the HPLC‐DAD methods were developed for quantitative analysis of the P. pseudoginseng roots showed that compounds 4, 6, 8, and 10 are the main components with the corresponding content of 0.74, 3.02, 0.65, and 3.58 % of the dried sample. This developed HPLC‐DAD method provides an adequate linearity (R² > 0.999). This validated method was also conducted to determine four main components of P. pseudoginseng roots.