An Herbal Formula (GPC) Suppresses the Releases of Pro-Inflammatory Effectors in Lipopolysaccharide/Peptidoglycan-Activated RAW264.7 Macrophages and Reduces the Extent of Chemical-Induced Acute/Chronic Inflammation in Rodents

Abstract

Pharyngitis (an inflammation in the pharynx) is a commonly occurring symptom of upper respiratory tract infection in patients suffering from common cold. The high prevalence of upper respiratory tract infection necessitates a safe and effective antiinflammatory agent for pharyngitis. Chinese herbal medicine, which has been clinically prescribed for thousands of years, may offer a basis for the treatment of common cold as well as the amelioration of pharyngitis. In the present study, we investigated the in vitro and in vivo anti-inflammatory activities of a Chinese herbal formula, namely GPC, which is comprised of Glycyrrhiza Radix, Platycodonis Radix, Citri Reticulatae Pericarpium, Phyllanthi Fructus and Taraxaci Herba. Incubation with GPC (30, 100 and 300 μg/mL) suppressed the releases of tumor necrosis factor α (TNF- α ), interleukin 6 (IL-6) and nitric oxide in lipopolysaccharide/peptidoglycanactivated RAW264.7 macrophages. In addition to the cell-based study, long-term treatment with GPC (0.35, 1.05 and 2.10 mL/kg/day × 30 doses) was found to reduce the extent of inflammation in animal models of carrageenan-induced paw edema (acute inflammation) as well as cotton pellet-induced granuloma formation (chronic inflammation) in mice. The ability of GPC to enhance the tracheobronchial expectorant action suggested its immunomodulatory activity in the respiratory tract. This postulation was supported by the observation that GPC reduced the degree of pharyngitis and reversed the changes in plasma TNF-α and IL-6 levels in capsaicininduced pharyngitis in rats. The ensemble of results suggests that GPC may offer a promising prospect for alleviating the extent of pharyngitis by virtue of antiinflammatory activities.