Evaluation of tussilagone: a cardiovascular-respiratory stimulant isolated from Chinese herbal medicine.

1. Traditional Chinese herbal medicine has long used Kuandong Hua (Tussilago farfara L.) in the treatment of various respiratory conditions. 2. Recently, it has been found that an extract of this plant (7R,14R)-14-acetoxy-7-[(2'E)-3'-methylpent-2'-enoyloxy ]-oplopanone, is a potent cardiovascular and respiratory stimulant. 3. This compound has been named Tussilagone (TUS) and when administered intravenously, has been shown to produce an instant and dose dependent pressor effect in anesthetized dogs (0.02-0.3 mg/kg), cats (0.02-0.5 mg/kg), and rats (0.4-4 mg/kg). 4. This pressor effect is similar to that of dopamine; however, no tachyphylaxis has been observed. 5. In addition to its cardiovascular effects TUS produced a significant stimulation of respiration in experimental animals. 6. The acute intravenous LD50 in mice of this compound was 28.9 mg/kg.