Total Flavonoid Extract of Pseudocedrela kotschyi (Schweinf) Harms (Meliaceae) Inhibits the Pro-Inflammatory Function of Asthmatic Patients Neutrophils

Background and objective: In asthmatic patients, neutrophils are known to be hyperactive, characterized by a production of numerous inflammatory mediators. The present study aimed to evaluate the effect of total flavonoid extract (TFE) of Pseudocedrela kotschyi (P. kotschyi) on neutrophil activities and anaphylactic reactions. Methods: Extract was tested on neutrophils isolated from blood of asthmatic patients activated by N-formyl-L-methionyl-L-leucyl-phenylalanine (fMLP) or histamine, and on anaphylactic reaction induced by horse serum and Bacillus Calmette-Guérin (BCG) vaccine intraperitoneal in albino Wistar rats. In vitro, fMLP-induced production of peroxidase activity, superoxide anion (O2 -), tumor necrosis factor alpha (TNF-α) and leukotriene B4 (LTB4), and histamine-induced production of nitric oxide (NO) and hydrogen peroxide were evaluated, while blood total and differential leukocytes, and level of NF-α and LTB4 in bronchoalveolar lavage fluid were measured in rat. Results: Treatment with TFE of P. kotschyi exhibited significant reduction in the peroxidase activity (IC50, 76.03 μg/ml), O2 (IC50, 84.89 μg/ml), TNF-α (IC50, 54.07 μg/ml) and LTB4 (IC50, 48.97 μg/ml) production by fMLP-stimulated neutrophils. Moreover, TFE displayed markedly reduction in NO (IC50,37.31 μg/ml) and H2O2 (IC50, 32.05 μg/ml) production by the histamine-activated neutrophils. In addition, the treatment of rat with TFE brought to normalcy, the increased total white blood cells, neutrophil and eosinophils in blood, TNF-α and LTB4 in bronchoalveolar lavage fluid. Conclusion: Results of study indicated that stem bark lavonoids of P. Kotschyi could be effective in the treatment of anaphylaxis and asthma.