Showing papers on "Antitussive Agent published in 2008"

Antitussive stemoninine alkaloids from the roots of Stemona tuberosa.

Abstract: Investigation of the roots of Stemona tuberosa afforded five minor constituents, stemoenonine (1), 9a- O-methylstemoenonine (2), oxystemoenonine (3), 1,9a- seco-stemoenonine (4), and oxystemoninine (5), along with the known compound stemoninoamide (6). Their structures were elucidated by 1D and 2D NMR spectra and other spectroscopic studies. Alkaloids 1, 2, and 6, as well as the representative stemoninine-type alkaloid, stemoninine (7), were screened for antitussive activity in the citric acid-induced guinea pig cough model. Compounds 6 and 7 exhibited strong antitussive activity after oral and intraperitoneal administrations.

Antitussive Effect of Thymoquinone, a Constituent of Nigella Sativa Seeds, in Guinea Pigs

Abstract: The antitussive activity of thymoquinone, a constituent of Nigella sativa seeds, was evaluated using the nebulized solution of citric acid 20 % in guinea pigs. Thymoquinone and codeine were injected intraperitoneally. Thymoquinone (20 and 40 mg/kg) and codeine (5 mg/kg), a prototype antitussive agent, reduced the number of cough in animals. The antitussive effect of these agents was antagonized by pretreatment with naloxone (2 mg/kg), an opioid receptor antagonist. These results suggest that thymoquinone has antitussive

TRPV1 Antagonists as Potential Antitussive Agents

Abstract: Cough is an important defensive pulmonary reflex that removes irritants, fluids, or foreign materials from the airways. However, when cough is exceptionally intense or when it is chronic and/or nonproductive it may require pharmacologic suppression. For many patients, antitussive therapies consist of OTC products with inconsequential efficacies. On the other hand, the prescription antitussive market is dominated by older opioid drugs such as codeine. Unfortunately, “codeine-like” drugs suppress cough at equivalent doses that also often produce significant ancillary liabilities such as GI constipation, sedation, and respiratory depression. Thus, the discovery of a novel and effective antitussive drug with an improved side effect profile relative to codeine would fulfill an unmet clinical need in the treatment of cough. Afferent pulmonary nerves are endowed with a multitude of potential receptor targets, including TRPV1, that could act to attenuate cough. The evidence linking TRPV1 to cough is convincing. TRPV1 receptors are found on sensory respiratory nerves that are important in the generation of the cough reflex. Isolated pulmonary vagal afferent nerves are responsive to TRPV1 stimulation. In vivo, TRPV1 agonists such as capsaicin elicit cough when aerosolized and delivered to the lungs. Pertinent to the debate on the potential use of TRPV1 antagonist as antitussive agents are the observations that airway afferent nerves become hypersensitive in diseased and inflamed lungs. For example, the sensitivity of capsaicin-induced cough responses following upper respiratory tract infection and in airway inflammatory diseases such as asthma and COPD is increased relative to that of control responses. Indeed, we have demonstrated that TRPV1 antagonism can attenuate antigen-induced cough in the allergic guinea pig. However, it remains to be determined if the emerging pharmacologic profile of TRPV1 antagonists will translate into a novel human antitussive drug. Current efforts in clinical validation of TRPV1 antagonists revolve around various pain indications; therefore, clinical evaluation of TRPV1 antagonists as antitussive agents will have to await those outcomes.

Structure-antitussive activity relationships of naltrindole derivatives. Identification of novel and potent antitussive agents.

Abstract: We have previously reported antitussive effects of naltrindole (NTI), a typical delta opioid receptor antagonist, in a rat model. The ED50 values of NTI by intraperitoneal and peroral injections were 104 microg/kg and 1840 microg/kg, respectively, comparable to those of codeine. Codeine, one of the most reliable centrally acting antitussive drugs, has micro agonist activity and thus the same side effects as morphine, e.g., constipation, dependency, and respiratory depression. Because NTI is a delta opioid antagonist, its derivatives have potential as highly potent antitussives, free from the mu opioid agonist side effects. We attempted to optimize the NTI derivatives to develop novel antitussive agents. On the basis of the studies of structure-antitussive activity relationships of alkyl substituted NTI derivatives, we designed NTI derivatives with extra ring fused structures. As a clinical candidate, we identified a highly potent new compound, (5R,9R,13S,14S)-17-cyclopropylmethyl-6,7-didehydro-4,5-epoxy-5',6'-dihydro-3-methoxy-4'H-pyrrolo[3,2,1-ij]quinolino[2',1':6,7]morphinan-14-ol (5b) methanesulfonate (TRK-850) which was effective even by oral administration (ED50 6.40 microg/kg).

Antitussive activity of ethanolic extract of Curcuma aromatica rhizomes on sulfur dioxide induced cough in mice.

Abstract: Ethanolic extract of rhizomes of Curcuma aromatica (Zingiberaceae) was investigated for its antitussive effect on Sulfur dioxide induced cough model in mice. The extract exhibited significant antitussive activity in a dose dependant manner. The activity was compared with the prototype antitussive agent codeine phosphate. The ethanolic extract at the dose of lOOmg. 200mg and 400mg/kg body weight, po, showed 68%, 74% and 79% of inhibition of cough with respect to control group.