Dioscin and methylprotodioscin isolated from the root of Asparagus cochinchinensis suppressed the gene expression and production of airway MUC5AC mucin induced by phorbol ester and growth factor

Background: The root of Asparagus cochinchinensis (Lour.) Merr. has been utilized as mucoregulators and expectorants for controlling the airway inflammatory diseases in folk medicine.

Hypothesis/purpose: We investigated whether dioscin and methylprotodioscin isolated from the root of Asparagus cochinchinensis (Lour.) Merr. suppress the gene expression and production of airway MUC5AC mucin induced by phorbol ester and growth factor.

Study design: Confluent NCI-H292 cells were pretreated with dioscin or methylprotodioscin for 30 min and then stimulated with EGF or PMA for 24 h. The MUC5AC mucin gene expression was measured by RT-PCR. Production of MUC5AC mucin protein was measured by ELISA.

Results: (1) Dioscin and methylprotodioscin suppressed the expression of MUC5AC mucin gene induced by EGF or PMA; (2) dioscin suppressed the production of MUC5AC mucin induced by either EGF at 10(-5) M (p < 0.05) and 10(-6) M (p < 0.05) or PMA at 10(-4) M (p < 0.05), 10(-5) M (p < 0.05) and 10(-6) M (p < 0.05); (3) methylprotodioscin also suppressed the production of MUC5AC mucin induced by either EGF at 10(-4) M (p < 0.05) or PMA at 10(-4) M (p < 0.05).

Conclusion: These results suggest that dioscin and methylprotodioscin isolated from the root of Asparagus cochinchinensis suppress the gene expression and production of MUC5AC mucin, by directly acting on airway epithelial cells, and the results are consistent with the traditional use of Asparagus cochinchinensis as remedy for diverse inflammatory pulmonary diseases.