Figure 2.

Hypericin and pseudohypericin are key components in the Hypericum perforatum (HP1) extract that are antivirally effective against the pseudo-typed VSV virus. (A–E) Vero cells were seeded overnight, and the next day, different concentrations of hypericin (HY), pseudohypericin (PS), hyperforin (HF), procyanidin-C1 (PRO), and quercetin-3-O-glucuronid (ingredients of HP1 extract) were applied onto the cells for indicated time points, as solvent-treated cells (DMSO) served as control. In addition, Staurosporine-treated cells served as positive control. After the incubations, the MTT assay-based cytotoxicity was measured, cell viability as % of solvent control is shown (mean and s.d), and two-way ANOVA with Dunnett’s Multiple comparisons was done by comparing each value with the solvent control at each time point. (F–J) Vero cells were seeded overnight, and on the next day, cells and the VSV-pseudo-typed virus were incubated with the indicated substances or solvent control (DMSO) for 1 h prior to infection, at 37 °C or room temperature, respectively. After the pre-incubation, infection was performed with a MOI of 0.01 for 1 h, and cells were finally washed and incubated without further treatments. GFP-positive cells as % of solvent control are shown (mean and s.d.), and Student’s t-test with Welch’s correction was applied (n.d. means non-detected, while n.s. means non-significant statistical difference). * for p ≤ 0.05, ** for p ≤ 0.01, *** for p ≤ 0.001, and **** for p ≤ 0.0001.