Evaluation of pharmacodynamic activities of EPs® 7630, a special extract from roots of Pelargonium sidoides, in animals models of cough, secretolytic activity and acute bronchitis

EPs® 7630 is a proprietary aqueous-ethanolic extract from roots of Pelargonium sidoides DC and has been demonstrated to dispose among others of antibacterial, antiviral, immunomodulatory, antioxidant, and tissue-protective activity. It is an approved medicinal product in more than 50 countries for the treatment of airway infections such as acute bronchitis, common cold, and sinusitis. While the pharmacological effects of EPs® 7630 have extensively been evaluated in diverse in vitro test systems, the number of publications reporting results from in vivo models is limited. In the present study antitussive, secretolytic, and anti-inflammatory effects of EPs® 7630 were assessed in animal experiments following oral administration at human equivalent doses. Antitussive effects were evaluated using ammonia- and citric acid-induced models of cough in mice (20, 40, 120 mg/kg) and guinea pigs (10, 20, 45 mg/kg), respectively. For the determination of secretolytic activity tracheobronchial secretion of intraperitoneally injected phenol red was determined in mice, while antiinflammatory action was assessed in an acute bacterial bronchitis model in rats. A significant and dose-dependent reduction of cough frequency was observed in both cough models, which was accompanied by a prolongation of cough latency time. Similarly, the extract exerted a marked secretolytic activity in mice. Induction of acute bacterial bronchitis caused characteristic histopathological changes in lung tissue adjacent to trachea and bronchi. The degree of these lesions was significantly reduced in rats treated with EPs® 7630 at doses of 30 and 60 mg/kg. This protective effect at least partially seems to be mediated by an up-regulation of superoxide dismutase and a subsequent protective effect against oxidative stress as indicated by a reduced serum level of malondialdehyde. The present data further support the therapeutic use of EPs® 7630 in respiratory tract infections and provide a basis for detailed studies on its bioactive constituents as well as their in vivo mode of action.