Comparative studies of saponins in 1-3-year-old main roots, fibrous roots, and rhizomes of Panax notoginseng, and identification of different parts and growth-year samples

Notoginsenosides R₁, R₄, Fa, and K (N-R₁, N-R₄, N-Fa, and N-K), as well as ginsenosides Rg₁, Rb ₁, Rd, Re, Rf, Rg₂ and Rh₁ (G-Rg₁, G-Rb₁, G-Rd, G-Re, G-Rf, G-Rg₂ and G-Rh₁) in 47 Notoginseng samples including 1-, 2- and 3-year-old main roots, rhizomes and fibrous roots of Panax notoginseng were determined by high-performance liquid chromatography-diode array detection method. Total contents (%) of the 11 saponins were 9.82-14.57 for 2-year old and 14.20-16.00 for 3-year-old rhizomes; 2.72-4.50 for 2-year-old and 1.98-4.92 for 3-year-old fibrous roots; 1.75-3.05 for 1-year-old whole roots; and 3.71-8.98 for 2-year-old and 7.03-11.23 for 3-year-old main roots. Contents of most saponins and total content of 11 saponins were in the order 3- >2- >1-year-old main root samples. G-Rf content, sum of G-Rf and G-Rh₁ were, respectively, 0.08-0.18 and 0.14-0.32 for 2- or 3-year-old rhizomes, and 0.01-0.07 and 0.03-0.10 for 2- or 3-year-old main roots. Combined contents of N-R₁, G-Rg₁ and G-Rb₁ were 5.78-9.37 in 3-year-old main roots, and 2.99-7.13 in 2-year-old main roots, of which nearly one-third of samples were lower than the limit (5 %) in the Chinese Pharmacopoeia. Those of 2- or 3-year-old fibrous roots (1.47-3.83) and 1-year-old whole roots (1.41-2.44) were much lower than the limit, and were considered not suitable for use as Notoginseng. Two-year-old main roots are not appropriate for collection as Notoginseng. Different parts and growth years of P. notoginseng can be identified from each another according to differences in saponin content.