Chemical onstituents and mechanism of Corydalis Rhizoma based on HPLC-QTOF/MS and G protein-coupled receptor analysis

The chemical constituents of Corydalis Rhizoma were identified in the 60% ethanol extract using high performance liquid chromatography/electrospray ionization quadruple time-of-flight mass spectrometry (HPLC-QTOF/MS). The stimulation and inhibition effects of Corydalis Rhizoma and its representative compounds (protopine, palmatine, tetrahydropalmatine) on G protein-coupled receptor (GPCR), including 5-hydroxytryptamine 1A receptor (5-HT_1A), μ opioid receptor (OPRM1), β₂ adrenergic receptor (ADRB2), dopamine receptor (D₂), acetylcholine receptor (M₂) and thromboxane-prostaglandin receptor (TP) were explored using the fluorescence assay of intracellular calcium ion. As a result, 31 compounds were obtained and 28 alkaloid compounds were identified. The results of GPCR experiments showed that Corydalis Rhizoma could activate 5-HT_1A, OPRM1, ADRB2 receptors and block D₂ receptor. Protopine showed antagonism on D₂ and M₂ receptors, tetrahydropalmatine could agitate ADRB2 receptor and antagonize D₂ and TP receptors, while palmatine showed no significant biological activity on the 6 GPCRs. In conclusion, Corydalis Rhizoma may exert biological activity by multi-components acting on multi-targets.