Hydrastinine hydrochloride is a semisynthetic alkaloid from the hydrolysis of the alkaloid Hydrastine, used as a haemostatic drug.

Cyclic AMP-dependent protein kinase activity is assayed in a reaction mixture containing, in a final volume of 0.2 mL, 50 mM Tris-HCl (pH 7.0), 10 mM magnesium acetate, 2 mM EGTA, 1 μM cyclic AMP or absence of cyclic AMP, 3.3 to 20 μM [r-32P] ATP (4×105 c.p.m.), 0.5 μg of the enzyme, 100 μg of histone H2B and compound. The mixture is incubated at 30°C for 5 min. The reaction is terminated by adding 1mL of ice-cold 20% trichloroacetic acid after adding 500 μg of bovine serum albumin as a carrier protein. The sample is centrifuged at 3000 r.p.m. for 15min, the pellet is resuspended in ice-cold 10% trichloro-acetic acid solution and the centrifugation-resuspension cycle is repeated three times. The final pellet is dissolved in 1 mL of 1 N NaOH and radioactivity is measured with a liquid scintillation counter[1].