Nuphar lutea Extracts Exhibit Anti-Viral Activity against the Measles Virus

Figure 1. The effect of Nuphar lutea (NUP) on survival of measles virus (MV) acutely infected cells. VERO cells were infected with double dilutions of measles virus (MV) (maximum Multiplicity of Infection (MOI)—2.5). The cells were treated with 0.3 µg/mL NUP, either 24 h before infection (dots), simultaneously (light grey), or 24 h after infection (stripes). Cell survival was determined by the tetrazolium based cell proliferation (viability) test 96 h post infection. Statistical analysis (p < 0.05 *, p < 0.01 **) and a moving average trend line is presented. MV infected but Nuphar lutea (NUP) untreated cells were used as a reference for statistical analysis.

Figure 2. L428 cells persistently infected with MV-GFP. The GFP MV virus was detected by fluorescence microscopy (X 200).

Figure 3. Expression of P- and N-MV proteins following NUP treatment. L428 + MV cells were incubated for 12 h without NUP (Control) or with 6 µg/mL NUP. Immunohistochemistry with antibodies against P- and N-MV proteins was performed (X 400). Positive staining is brown. The nuclei were counterstained with hematoxylin (blue).

Figure 4. Expression of P-, N-, and V-MV proteins following NUP treatment by a Western blot. Western blot analysis was performed on whole cell lysates from L428 + MV cells. Antibodies used were against P-, N-, and V-MV proteins. L428 + MV cells were incubated with different concentrations of NUP for 12 h. Densitometry of the blot is presented and normalized to β-actin.

Figure 5. Effect of NUP on P- and N-MV genes’ RNA expression. L428 + MV cells were incubated with different concentrations of NUP for 12 h. After incubation, total RNA isolation and qRT-PCR were performed. MV primers and probes were against N- and P- protein, human β-actin, and PHP genes were used for normalization. After normalization of N- or P- cycles with either β-actin or PHP, the control values were subtracted from the values of the normalized NUP-treated samples (∆Ct). (A) N gene normalized to β-actin gene, (B) P- gene normalized to β-actin gene, (C) N- gene normalized to PHP gene, and (D) P-gene normalized to PHP gene.

Figure 6. Members of the thioalkaloid family present in the NUP semi-purified extract.