MATERIALS AND METHODS: The composition of L. rhinocerotis TM02 cultivar was analyzed. Organ bath experiment was employed to study the bronchodilator effect of Lignosus rhinocerotis cold water extract (CWE) on rat isolated airways. Trachea and bronchus were removed from male Sprague-Dawley rats, cut into rings of 2 mm, pre-contracted with carbachol before adding CWE into the bath in increasing concentrations. To investigate the influence of incubation time, tissues were exposed to intervals of 5, 15 and 30 min between CWE concentrations after pre-contraction with carbachol in subsequent protocol. Next, tissues were pre-incubated with CWE before the addition of different contractile agents, carbachol and 5-hydroxytrptamine (5-HT). The bronchodilator effect of CWE was compared with salmeterol and ipratropium. In order to uncover the mechanism of action of CWE, the role of beta-adrenoceptor, potassium and calcium channels was investigated.

METHODS: A crude methanol extract of the aerial parts of Isodon rugosus (Ir.Cr.) was used for both in vitro and in vivo experiments. The plant extract was tested on isolated rabbit jejunum preparations for possible presence of spasmolytic activity. Moreover, isolated rabbit tracheal and aorta preparations were used to ascertain the relaxant effects of the extract. Acetylcholinesterase and butyrylcholinesterase inhibitory activities of Ir.Cr were also determined as well as its antioxidant activity. The in vivo antiemetic activity of the extract was evaluated by using the chick emesis model, while the analgesic and antipyretic activities were conducted on albino mice.

RESULTS: The application of the crude extract of I. rugosus to isolated rabbit jejunum preparations exhibited relaxant effect (0.01-0.3 mg/ml). The Ir.Cr also relaxed K+(80 m M)-induced spastic contractions in isolated rabbit jejunum preparations and shifted the Ca+2 concentration response curves towards right (0.01-0.3 mg/ml). Similarly, the extract, when applied to the isolated rabbit tracheal preparations relaxed the carbachol (1 μM)--as well as K+ (80 mM)-induced contractions in a concentration range of 0.01-1.0 mg/ml. Moreover, it also relaxed (0.01-3.0 mg/ml) the phenylephrine (1 μM)- and K+ (80 mM)-induced contractions in isolated rabbit aorta preparations. The Ir.Cr (80 mg/kg) demonstrated antipyretic activity on pyrogen-induced pyrexia in rabbits as compared to aspirin as standard drug. The Ir.Cr also exhibited anti-oxidant as well as inhibitory effect on acetyl- and butyryl-cholinesterase and lipoxygenase (0.5 mg/ml).