Fresh ginger (Zingiber officinale) has anti-viral activity against human respiratory syncytial virus in human respiratory tract cell lines

Ethnopharmacological relevance

Ginger, Zingiber officinale Roscoe, is a common spice and also a widely used medicinal plant in ancient China. Ginger is an ingredient of Ge-Gen-Tang (Kakkon-to; GGT). GGT has been proved to have antiviral activity against human respiratory syncytial virus (HRSV). However, it is unknown whether ginger is effective against HRSV.

Aim of the study

To find a readily available agent to manage HRSV infection, the authors tested the hypothesis that ginger can effectively decrease HRSV-induced plaque formation in respiratory mucosal cell lines.

Materials and methods

Effect of hot water extracts of fresh and dried gingers on HRSV was tested by plaque reduction assay in both human upper (HEp-2) and low (A549) respiratory tract cell lines. Ability of ginger to stimulate anti-viral cytokines was evaluated by enzyme-linked immunosorbent assay (ELISA).

Results

Fresh ginger dose-dependently inhibited HRSV-induced plaque formation in both HEp-2 and A549 cell lines (p<0.0001). In contrast, dried ginger didn't show any dose-dependent inhibition. 300 μg/ml fresh ginger could decrease the plaque counts to 19.7% (A549) and 27.0% (HEp-2) of that of the control group. Fresh ginger was more effective when given before viral inoculation (p<0.0001), particularly on A549 cells. 300 μg/ml fresh ginger could decrease the plaque formation to 12.9% when given before viral inoculation. Fresh ginger dose-dependently inhibited viral attachment (p<0.0001) and internalization (p<0.0001). Fresh ginger of high concentration could stimulate mucosal cells to secrete IFN-β that possibly contributed to counteracting viral infection.

Conclusions

Fresh, but not dried, ginger is effective against HRSV-induced plaque formation on airway epithelium by blocking viral attachment and internalization.