Investigation on the anti-inflammatory activity and mechanism of Dendrobium extract in vitro and in vivo

Abstract

Dendrobium, a traditional Chinese herbal Medicine, is widely used in China and Southeast Asian countries clinically for maintaining gastric tonicity and enhancing production of body fluid. It can relieve symptoms such as dryness of the throat and thirst with blurred vision. It also displays anti-inflammatory and antioxidant activities. Many kinds of bioactive constituents of Dendrobium have been identified. The polysaccharides, a macromolecules extract from Dendrobium, display immunomodulatory and hepatoprotective activities. Cigarette smoke-induced pulmonary inflammation has become a serious threat to people’s health. In Hong Kong, the second disease of mortality is pulmonary inflammation. Our research finds that the Polysaccharides of Dendrobium officinale (PDO), can promote AQP5 expression and inhibit MUC5AC expression. Lower expression of aquaporin 5 (AQP5) and higher expression of MUC5AC (a protein associated with phlegm formation) have been detected in SD rats with cigarette smoke-induced pulmonary inflammation, cigarette dust particles precipitate within the tracheal wall and the lungs, resulting in excessive phlegm secretion in the lungs. After PDO treatment, our experiment results revealed that the PDO was effective in alleviating cigarette smoke-induced pulmonary inflammation in SD rats by up-regulating AQP5 expression and reduce MUC5AC expression. This discovery reveals PDO can be developed into a drug for reducing damage to the respiratory tract caused by smoking and alleviating the pulmonary inflammation of patients. These findings also suggested that the components of Dendrobium have immunomodulatory activity and may contribute clinical application in the prevention and treatment of lung cigarette smoke-induced pulmonary inflammation. Acknowledgement: This study was supported financially by the Innovation and Technology Support Programme, the Government of the Hong Kong Administrative Region (Project code: ITS/313/11).