Lomatium dissectum Inhibits Secretion of CXCL10, a Chemokine Associated with Poor Prognosis in Highly Pathogenic Influenza A Infection

Objective: Lomatium dissectum is a plant native to the Western US traditionally used in the Native American culture to treat influenza, which remains a persistent threat to human health. Evidence suggests that dysregulation of cytokines and chemokines, including CXCL10, is the primary factor leading to poor prognosis in highly pathogenic influenza infection. This study was conducted to address the hypothesis that an aqueous extract of L. dissectum root inhibits CXCL10 secretion by human bronchial epithelial cells stimulated with polyinosinic:polycytidylic acid (poly i:c), a synthetic analog of viral dsRNA. Design: BEAS-2B cells treated with poly i:c were exposed to L. dissectum root aqueous extract simultaneously or at 2 h intervals up to 8 h post-stimulation. Supernatants were harvested at 24 h and enzyme-linked immunosorbent assay (ELISA) performed to determine CXCL10 concentrations. Results: L. dissectum root aqueous extract at 1 µg/mL significantly inhibited CXCL10 secretion (P=0.043, Anova, Tukey HSD) and demonstrated maximal inhibition 6 h post poly i:c exposure. MTT cytotoxicity assay results suggest that this inhibitory effect was not due to extract-induced cytotoxicity. Conclusion: The observation that L. dissectum extract inhibits CXCL10 secretion provides a plausible mechanism for the efficacy of L. dissectum in influenza treatment reported in ethnobotanical studies and case reports. L. dissectum may reduce morbidity and mortality associated with influenza and merits further research.