Abstract: The harvest time of medicinal mulberry leaves was required after frost. To evaluate the effects of frost process on mulberry, traditional efficacy of clearing away lung-heat and moisturizing were studied. Ammonia stimulate mouse cough model, electrical stimulate guinea pig cough model, rat trachea capillary expectoation drainage experiment and mouse airway phenol red excretion experiment were used to study the effects on clearing away lung-heat and moisturizing, antitussive and expectorant of mulberry leaves before (green mulberry leaves) and after frost (frosted mulberry leaves).The results showed that green mulberry leaves and frosted mulberry leaves inhibited the ammonia stimulate mouse cough with R value 134.85±3.17 and 156.84±11.72, respectively. The inhibition rate of cough were 24.58±5.38% and 37.68±7.29% (P<0.05), the inhibition rate of respiratory amplitude were 46.99±7.22% and 54.26±8.87% (P<0.05) respectively in guinea pig stimulated by electrical.Frosted mulberry leaves increased the amount of rat weasand expectoration drainage significantly in 4 hours (P<0.01). Mulberry leaves can improve the weasand of phenol red secretion in mice,the improvement rate of green mulberry leaves was 45.42±0.27% (P<0.05) and frosted mulberry leaves was 97.96±0.52% (P<0.01). Meanwhile, the results indicated that the effects of frosted mulberry leaves on antitussive and expectorant were better than that of green mulberry leaves.

Key words: mulberry leaves, frost, animal experiment, antitussive, expectorant