A new method for evaluating mucolytic expectorant activity and its application. II. Application to two proteolytic enzymes, serratiopeptidase and seaprose.

Using our new method described in a preceding paper, in vivo effects of two proteolytic enzymes such as serratiopeptidase (SER) and seaprose (SAP) on sputa collected from bronchitis rabbits were examined. SER (20 mg/kg) and SAP (30 mg/kg) significantly reduced the viscosity of sputum (P less than 0.05) at the 1-3-h periods and the 4-6-h periods, respectively, after intraduodenal administration. 50 mg/kg of SER also significantly decreased not only viscosity (P less than 0.001) but also amount of freeze-dried substance (P less than 0.05) of sputum at the 1-3-h periods, but SAP did not affect the amount of dried substance. Both enzymes significantly increased the volume of sputum, probably as the result of liquefaction. Thus, mucolytic expectorant activity of both enzymes can be demonstrated first by the reduction in viscosity and next of the increase in volume of sputa. However, the decrease in amount of freeze-dried substance is not always in accord with the reduction viscosity.