Virucidal and antiviral activities of maca (Lepidium meyenii) root powder on three pathways of Norovirus as a foodborne pathogen

Vitamin C equivalency, the cytotoxicity on murine macrophage cells, and the virucidal and antiviral activities of maca (Lepidium meyenii) powder on murine norovirus (MNV) as a norovirus surrogate for human as a foodborne pathogen were studied. The antioxidant capacity of the maca was determined by MTT assay as vitamin C equivalency (VCEAC). The 50% cytotoxic concentration (CC50) was calculated with the linearity of maca concentrations-cell viability. The activities of maca against the virus was determined as the 50% tissue culture infective dose with Spearman–Karber method. The VCEAC of maca linearly increased with the concentration. The non-cytotoxic concentrations of maca were measured on murine macrophage with a CC50 of 5.77 mg/mL and a CC80 of 1.28 mg/mL. As maca reduced the virus titration based on contact time in the virucidal assay in several conditions, it did not significantly inhibit MNV on three infectivity pathways of host cell at non-cytotoxic concentrations of maca. The result of this first study presented that despite its ineffective in the treatment and prophylaxis of norovirus infection, maca might be an alternative food additive and preservative against human norovirus as an important foodborne pathogen causing outbreaks worldwide.