New Theophylline Derivatives: Design, Synthesis, Antiasthmatic, and Antibacterial Activities

Methylxanthines especially theophylline have been recognized as potent bronchodilators for the relief of acute asthma for over 65 years. Recently, it was found that bacterial infection plays a role in asthma pathogenesis. Accordingly, the present work involves the synthesis of different series of 8-substituted theophylline derivatives as novel antiasthmatic candidates with potential antibacterial activity. A pharmacophore model was constructed to get useful insight into the essential structural features of bronchodilator activity. Forty-six of the target compounds were investigated for in vivo antiasthmatic activity using aminophylline as a reference standard. Antibacterial activity of all the target compounds was investigated in vitro against both Gram-positive and Gram-negative bacterial strains using ampicillin as a reference standard. Acute toxicity study was also performed. It is noteworthy to mention that compounds 6c, 8i1, and 14c combined both promising antiasthmatic and antibacterial activities. These compounds may act as a corner stone for further investigations by medicinal chemists in development of new theophylline derivatives for the treatment of bronchial asthma.