Asthma-Induced Inflammatory Responses and Reversal by Botanicals

Asthma is the most prevailing chronic inflammatory medical condition which is the outcome of extensive air pollution and which is associated with hyper-responsiveness of the respiratory system. Asthma causes excessive mucus production, blockage of air-passage, triggers inflammatory allergic responses, chronic lung infection, lifelong breathing troubles, and prolonged hospitalization in worst cases. Plant derived pollens may trigger asthmatic responses but on the other hand a number of medicinal plants and phytochemicals have been reported to ameliorate the symptoms associated with asthma. According to ethnomedicinal reports inhalation of certain kinds of herbs and administration of certain plant products could alleviate breathing and respiratory complexities. A number of animal model based studies have highlighted the role of plant extracts (PEs) and plant derived phytochemicals could alter the inflammatory responses by modulating the production of immunoglobulin E (IgE) and pro-inflammatory cytokine based immune signals. They could also suppress the accumulation of inflammatory cells which may lead to “hyper-drive” stage in respiratory system. Detailed analysis have highlighted the effective role of plant extracts and secondary metabolites modulating the release of TNF-α, IL-1β, IL-2, 4, 5, 6, 8, 13, IFN-γ, and other messenger molecules. Along with the experimental details and possible molecular mechanisms of the anti-asthmatic botanicals, this review also highlights constraints in medicinal plant oriented anti-asthmatic research, protocol based lacunae, details of toxicity and quality control studies and tries to link the traditional knowledge with laboratory-based findings.