ABSTRACT
Objective To investigate the relationship between the content of flavonoids and the key enzyme genes expression in different tissues of Bupleurum chinense and B. scorzonerifolium. Methods The roots, stems, leaves, and fruits of B. chinense and B. scorzonerifolium were used as test materials, determination of flavonoids (rutin, quercetin, kaempferol, and isorhamnetin) in different tissues by HPLC, determination of total flavonoids by UV spectrophotometry, the tissues expression of key enzyme genes (IFS, F3H, and DFR) in flavonoids synthesis was determined by real-time quantitative PCR, correlation analysis was performed with SPSS. Results The content of flavonoids in the aerial parts (stems, leaves, and fruits) of B. chinense and B. scorzonerifolium was significantly higher than that in roots, the content of flavonoids was mainly rutin, and the content of rutin in the leaves of B. chinense leaves was up to 106.961 mg/g; The distribution of total flavonoids in B. chinense and B. scorzonerifolium was obviously different, the content was from high to low: leaves ≥ fruit > stem > root; The expression of B. chinense IFS, F3H, and DFR gene in the aerial parts was much higher than that in roots, IFS gene was significantly positive correlated with rutin (P < 0.05), F3H gene was significantly positive correlated with DFR gene (P < 0.05), but the expression of IFS, F3H, and DFR gene in each tissues of B. scorzonerifolium was at lower level. Conclusion The content of flavonoids in different parts of B. chinense and B. scorzonerifolium was consistent with the expression of flavonoids synthesis key enzyme genes, the differential expression of key enzyme genes regulates the synthesis and accumulation of flavonoids in different tissues.