The antitussive effects of silverweed

A Chinese study evaluated the traditional use of silverweed (Potentilla anserina) as a folk medicine for fits of coughing. They tested extracts made from the root of the medicinal herb for their antitussive and expectorant activity.

The Lanzhou University of Technology supported the study. Its results were published in the science journal Pharmaceutical Biology.

• Silverweed roots were processed into an ethanol extract, a water-based aqueous extract, and polysaccharides. The antitussive effects of the products were tested on three different animal models. Coughing in mice was induced by either ammonia or sulfur dioxide, while guinea pigs were given citric acid.
• Both high and low doses of the aqueous extract and the polysaccharides were able to reduce the amount of artificially-induced coughing in mice and guinea pigs significantly. They also increased the amount of time between coughing fits in guinea pigs.
• Phenol red secretion tests demonstrated that the aqueous extract and polysaccharides achieved considerable effectiveness as expectorants. The 600 milligrams per kilogram (mg/kg) dose of polysaccharides outperformed a much higher amount (1,000 mg/kg) of its positive control counterpart ammonium chloride by 3.7 percent.
• The ethanol extract was much less effective. Only the high dose (600 mg.kg) demonstrated any antitussive activity. It only achieved this effect in the mouse model with the sulfur dioxide-induced coughing test.
• In all three tests, the polysaccharides performed better than the aqueous extract. The higher bioactivity of polysaccharides appears to indicate their importance.

The study presented evidence that supported the antitussive and expectorant properties of silverweed root. It further noted that the polysaccharides appear to be the primary active ingredients of the traditional Chinese medicine.

This site contains the full version of this study.

Meanwhile, ChineseMedicine.news has more stories about silverweed and other natural cough medicines.

Journal Reference:

Guo T, Wei JQ, Ma JP. ANTITUSSIVE AND EXPECTORANT ACTIVITIES OFPOTENTILLA ANSERINA. Pharmaceutical Biology. 22 December 2015;54(5):807–811. DOI: 10.3109/13880209.2015.1080734.