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[Research on dynamic accumulation of nine ginsenosides and two pseudo-ginsenosides of Panax quinquefolium root of different growth years and harvest months in Canada].

OBJECTIVE
To research the dynamic accumulation of ginsenosides Rg1, Re, Rb1, Rg2, Rc, Rb2, Rb3, Rd, Rg3 and pseudo-ginsenosides F11,RT5, which was grown from one- to five-year-old and harvested from May to September of Panax quinquefolium root in Canada.


METHODS
RP-HPLC-ELSD was adopted. The analysis was performed on a Dimaonsil C18 (250 mm x 4.6 mm, 5 μm) column, the mobile phase was acetonitrile (A)-deionized water (B) in gradient elution mode. The flow rate was 1.0 mL/min and column temperature was set at 30 °C. The carrier gas was nitrogen with flow rate of 2.8 L/min, the drift tube temperature was 100 °C, and the injection volume was 10 μL. The principle component analysis and cluster analysis of SPSS software (version 19.0) were conducted for the data analysis.


RESULTS
The RP-HPLC-ELSD method for determining simultaneously nine ginsenosides and two pseudo-ginsenosides was established. The total content of ginsenosides of one- to two-year-old was low and increased from May to September in each year. That of three- to five-year-old declined from June to July and increased from August, and was the highest in September of three- to five-year-old samples. The total content from September of three-year-old samples was similar. The content of nine ginsenosides and two pseudo-ginsenosides was relatively high in all the samples except ginsenoside Rc, which wasn't determined in some samples. The ginsenosides Rd, Rb3 and pseudo-ginsenoside F11 were higher than others. The principle component analysis results showed that ginsenosides Rg1, Re, Rb1, Rc, Rb2, Rb3, Rg3 and pseudo-ginsenosides F11,RT5 could be the characteristic ginsenosides of Panax quinquefolium root in Canada. The cluster analysis indicated that the chemical constituent and dynamic accumulation of ginsenosides of one- to two-year-old was similar except the sample of July of four-year-old and there was no obvious difference of three- to five-year-old.


CONCLUSION
With the consideration of the content of ginsenoside, cultivation cost of four- to five-year-old, and risk of waterlogging and plant diseases, it is suggested that Panax quinquefolium root from September of three-year-old can be regarded as the same quality.