Punica granatum and Citrillus colocynthis Aqueous Extracts Protect Mice from LPS-induced Lung Inflammation and Inhibit Metalloproteinases-2 and -9

Aim: Plants used in traditional medicine produce diverse active metabolites exhibiting various medicinal properties. For several centuries Citrillus colocynthis and Punica granatum have been used to treat inflammation, cancer, edema, bacterial infections and diabetes. The objectives of this work were to study the effect of C. colocynthis and P. granatum peel aqueous extracts, on activity of metalloproteinases, enzymes implicated in chronic inflammatory diseases such Chronic Obstructive Pulmonary Disease (COPD) and emphysema. Materials and Methods: Lung inflammation was induced in the mice (Strain BALB/c) by intra-tracheal instillation of lipopolysaccharide (5 µg/mouse) and P. granatum peel extract (PGE) or C. colocynthis peel extract (CCPAE) (200 mg/Kg body weight) was injected intraperitoneally prior to LPS administration. Bronchoalveolar lavage and lung tissue were collected to assess inflammatory cells count and total protein content. Metalloproteinases activity and expression was detected by RT-PCT and zymography techniques, respectively. Results: Results showed that PGE and CCPE decreased markedly neutrophils count and proteins leakage into Bronchoalveolar Lavage Fluid (BALF). Gelatin zymography assay showed that PGE inhibited MMP-2 and MMP-9 activity in BALF and in lung homogenates. However, CCPE inhibited MMP-2 and MMP9 in lung homogenates but only MMP-2 in BALF. Furthermore, both PGE and CCPAE inhibit MMP-2 and -9, expression in the lung. Conclusion: Our results showed that PGE and CCPAE exhibit anti-inflammatory and, antimetalloproteinases especially MMP-2 and -9, activities. According to these findings, these natural products could be used as a potential source of new compounds with anti-inflammatory and anti-metalloproteinases activity.