Therapeutic potential of indole alkaloids in respiratory diseases: A comprehensive review

Background: Indole alkaloids are very promising for potential therapeutic purposes and appear to be particularly effective against respiratory diseases. Several experimental studies have been performed, both in vivo and in vitro, to evaluate the effectiveness of indole alkaloids for the management of respiratory disorders, including asthma, emphysema, tuberculosis, cancer, and pulmonary fibrosis. Purpose: The fundamental objective of this review was to summarize the in-depth therapeutic potential of indole alkaloids against various respiratory disorders. Study design: In addition to describing the therapeutic potential, this review also evaluates the toxicity of these alkaloids, which have been utilized for therapeutic benefits but have demonstrated toxic consequences. Some indole alkaloids, including scholaricine, 19-epischolaricine, vallesamine, and picrinine, which are derived from the plant Alstonia scholaris, have shown toxic effects in non-rodent models. Methods: This review also discusses clinical studies exploring the therapeutic efficacy of indole alkaloids, which have confirmed the promising benefits observed in vivo and in vitro. Results: The indole alkaloidal compounds have shown efficacy in subjects with respiratory diseases. Conclusion: The available data established both preclinical and clinical studies confirm the potential of indole alkaloids to treat the respiratory disorders.