Figure 4.
Lindera obtusiloba leaf extract (LOLE) anti-noroviral effects on model food systems. Lettuce, cabbage, oyster and stainless-steel surfaces were spot-inoculated with murine norovirus (MNV-1) (105 PFU/mL) and plaque reduction assays were performed to determine the anti-noroviral effects of LOLE. (A,C,E,G) Dose-response experiments: MNV-1 virus particles were pretreated with LOLE solutions (1, 2, 4, 8, and 12 mg/mL) for 1 h at 25 °C before infecting RAW 264.7 cells. (B,D,F,H) Time-response experiments: virus particles were pretreated with LOLE (12 mg/mL) for 0, 5, 10, 30 and 60 min at 25 °C. MNV-1 infectivity was calculated as a percentage of plaque formation using dimethyl sulfoxide (DMSO)-treated samples as a control. The white bars represent the control groups, whereas the gray bars represent the intervention groups. Results are expressed as the percentage of neutralized virus compared to control (mean ± SEM; n = 3). * p < 0.05, ** p < 0.01, *** p < 0.001 vs. DMSO.