The aim of this study is to explore the differential distribution of flavonoids in the different parts of Polygonum capitatum and dig its potential medicinal value.Therefore,LC-MS and GC-MS metabolomics technology was used in comparatively researching the flavonoids in the stems,flowers and leaves of P. capitatum.It was established that the number of flavonoids in the P. capitatum aboveground part was ranked in descending order as follows:flower>leaf>stem.Additionally, based on the screening criteria (fold change ≥2 or ≤0.5,P＜0.05) of differentially expressed metabolites (DEMs),we obtained 333,289 and 366 DEMs in three groups of PC sample comparison (stems and flowers,stems and leaves,leaves and flowers),respectively.Subsequently,the DEMs in different medicinal parts of P. capitatum were significantly enriched in flavonoid biosynthesis pathway.In these DEMs,the relative concentration of these flavonoids (3′,4′,5′,5,7′-pentahydroxyflavone,epicatechin and epigallocatechin) in the flowers of P. capitatum was greater than that in the stems or leaves.Meanwhile,3′,4′,5′,5,7′-pentahydroxyflavone,epicatechin and epigallocatechin are important pharmacological active substance.The research comprehensively identified the flavonoids in the different medicinal parts of P. capitatum,and affirmed that the flavonoids were majorly distributed in the flower. These results provided the theoretical basis for deeply digging and utilizing the medicinal value of its flavonoids.

Polygonum capitatum;different medicinal parts;metabonomics;flavonoids;3′,4′,5′,5,7′-pentahydroxyflavone, epigallocatechin