- Introduction
Asthma, a chronic inflammatory disease of the airways, characterized by infiltration of T-lymphocytes and eosinophil, overproduction of mucus and airway hyper-responsiveness. Inflammatory mediators have a great role in the pathogenesis of chronic airway disease and facilitate the recruitment, activation, and trafficking of inflammatory cells in the airways. Inflammatory cells contribute to the generation of Th2 cytokines, chemokines, Tumour necrosis factor (TNF)-α and histamine (Liu et al., 1991), levels of which are increased in asthmatic lungs (Williams and Galli, 2000). Th2 cytokines participate in asthma pathogenesis by stimulating B-cells and induce the infiltration of eosinophils and other inflammatory cells into the airways (Hamelmann et al., 1999; Zhang et al., 1999). TNF-α, is usually associated with Th1 responses (Bazzoni and Beutler, 1996; Costa et al., 1993; Gordon and Galli, 1991 Meiler et al., 2006). Recent asthma research is focused on chronic inflammation and remodelling of the airways. Many medicinal plants are used in traditional system of medicine as an alternative to treat inflammatory diseases and have been known to provide relief from the symptoms, comparable to that obtained by allopathic medicines. Several extract/fractions along with plant derived secondary metabolites have been successfully reported to interfere directly or indirectly in the pathophysiology of inflammation. In this perspective, the crude 70% methanol extract and fractions (ethyl