[Grey correlation analysis and path analysis between isoflavones content in Astragali Radix and climate factors]

In this study, HPLC was used to determine the content of the four isoflavones of Astragalus membranceus var. mongholicus from different regions(calycosin-7-glucoside, ononin, calycosin and formononetin), and gray correlation analysis and path analysis were used to explore the influence of climate factors on the content of isoflavone components in A. membranceus var. mongholicus. The results showed that there were significant differences in the content of the four isoflavones in different areas(P<0.05); grey correlation analysis showed that the highest temperature in July, the lowest temperature in January and the daily average temperature had a greater impact on the content of flavonoid glycosides, meanwhile precipitation and relative humidity were the more important factors for the accumulation of flavonoid aglycones. According to the general analysis, the direct positive effects of the lowest temperature in January and altitude on the contents of four isoflavones in A. membranceus var. mongholicus were significant. High altitude and extreme temperature conditions might be more adverse to the formation and accumulation of isoflavone components. Therefore, the religions of A. membranceus var. mongholicus with high contents of isoflavones should be chosen the low altitude region with higher minimum temperature in January. This study provides a reference basis for the quality evaluation of A. membranceus var. mongholicus, and basic data for the selection of suitable habitat, construction of planting standards and directional cultivation of medicinal materials in A. membranceus var. mongholicus.