Study on the Hypoglycemic Activity of Different Components of Quzhiqiao in Vitro and Analysis of Four Flavonoids

OBJIECTIVE To study the hypoglycemic activity of different components of Quzhiqiao in vitro and clarify the content of 4 flavonoid compounds in each component. METHODS The flavonoids with different polarities were extracted and separated by system solvent method, their α-glucosidase inhibitory activity were demonstrated by inhibitory test of α-glucosidase in vitro, and their effects on the glucose consumption of HepG2 cells were also investigated. An HPLC method was established with an Agilent Zorbax SB C₁₈ column (250 mm×4.6 mm, 5 μm), acetonitrile-0.02% phosphoric acid solution (20:80) as the mobile phase, the flow rate was 1.0 mL·min^-1, the detection wavelength was 280 nm, and the column temperature was 35℃. Finally, the content of rutinine, naringin, hesperidin and neohesperidin in different components of Quzhiqiao were determined by external standard method. RESULTS The components of Quzhiqao had α-glucosidase inhibitory effects, their order of inhibitory activity was:n-butanol componentIC₅₀:(0.033±0.010) mg·mL^-1 > methanol componentIC₅₀:(0.092±0.006)mg·mL^-1 > ethyl acetate componentIC₅₀:(0.170±0.014)mg·mL^-1 > chloroform componentsIC₅₀:(0.509±0.070)mg·mL^-1. The methanol component and n-butanol component of Quzhiqiao could significantly promote the consumption of glucose in HepG2 cells and the differences were statistically significant (P<0.05). Through methodological certification, the parameters of content determination method were all in line with the requirements. And the experiment found that each component of Quzhiqiao was all composed of rutininenaringin, naringin, hesperidin and new hesperidin, and the n-butanol component had the highest content of flavonoids. CONCLUSION Each component of Quzhiqiao all have good α-glucosidase inhibitory activity, and the inhibitory effect is enhanced with the increase of the concentration of flavonoids in the components. Simultaneously, the higher content of flavonoids such as methanol component, n-butanol component and the ethyl acetate component all have the effect of promoting the glucose consumption of HepG2 cells.