Lomatium dissectum DECREASEs CXCL10 CHEMOKINE production in poly I:C-stimulated BEAS-2B human bronchial epithelial cells

Lomatium dissectum is a plant native to the Western U.S. widely used in the Native American culture and used traditionally to treat influenza. Worldwide, 3 to 5 million severe cases of influenza infection occur annually leading to 250,000 – 500,000 fatalities. Severe cases often result from fluid build-up in the lower respiratory tract leading to secondary pneumonia. Evidence suggests that cytokine and chemokine dysregulation is the primary factor leading to secondary pneumonia. Overproduction of the chemokine CXCL10 plays an important role in the pathogenicity of influenza. This study was conducted to address the hypothesis that a water extract of L. dissectum inhibits CXCL10 production by human bronchial epithelial cells stimulated with poly I:C (a TLR3 agonist and synthetic analog of viral dsRNA). BEAS-2B human bronchial epithelial cells treated with poly I:C were either treated simultaneously with L. dissectum water extract at increasing concentrations from 1 – 10 µg/ml, or at 2 hr intervals for 8 hr at 1 µg/ml. Supernatants were harvested at 24 hr and enzyme-linked immunosorbent assay (ELISA) performed to determine secreted CXCL10 concentrations. L. dissectum extract significantly inhibited (p,0.05, Anova, Tukey HSD) CXCL10 secretion dose-dependently and was most effective 6 hr post poly I:C exposure. Given that overproduction of CXCL10 is implicated in the pathogenesis of influenza, the observation that L. dissectum extract inhibits CXCL10 provides a possible mechanism for the efficacy of L. dissectum for influenza treatment observed in ethnobotanical research and case reports. L. dissectum may reduce morbidity and mortality associated with influenza and merits further research.