Traditional Chinese medicine is an ancient system of medicines used in China for thousands of years. In traditional Chinese medical practice, Corydalis yanhusuo W. T. Wang has been used for thousands of years. _{A 50 i}...[ Read more ]

Traditional Chinese medicine is an ancient system of medicines used in China for thousands of years. In traditional Chinese medical practice, Corydalis yanhusuo W. T. Wang has been used for thousands of years.

In this study, column chromatography, thin layer chromatography, mass spectrometry and radioactive-labeled receptor binding assay are used to study the active constituents in the crude extract of Corydalis yanhusuo W. T. Wang. One of the active components isolated from the Corydalis yanhusuo W. T. Wang called Y2 was found to be responsible for the binding activity to the central benzodiazepine binding site of the GABA_A receptor with an IC₅₀ value of 2.62 μM and K_i value of 0.61 μM.

The pharmacological effects of Y2 were then examined in mice. In the locomotor activity test, Y2 could reduce the locomotor activity in mice by 31 % (0.1 mg/kg, orally), 33 % (1 mg/kg and 10 mg/kg, orally), 36 % (30 mg/kg, orally), 73 % (50 mg/kg, orally) and 91 % (100 mg/kg, orally). In the elevated plus-maze test of anxiety, Y2 (0.1 mg/kg - 50 mg/kg) significantly elevated both the percentage of open arm entries and the time spent in the open arm areas in a dose-dependent manner, consistent with its anxiolytic properties. It did not significantly alter the total number of arm entries made by mice at the four different dosages (0.1 mg/kg, 1 mg/kg, 10 mg/kg and 30 mg/kg, orally), but significantly altered the total number of arm entries made by mice at 50 mg/kg. In the hole-board test, Y2 significantly reduced the number of head-dips, the time spent head-dipping, the number of rearings and the time spent in rearings with a minimum depressant dosage at 30 mg/kg and all these results indicate the sedative effect of Y2. In the horizontal-wire test, Y2 had no effect. These findings suggest that Y2 has hypnotic, anxiolytic and sedative effects without inducing muscle relaxation.