Research Article

A Laboratory Evaluation of Medicinal Herbs Used in China for the Treatment of Hand, Foot, and Mouth Disease

Figure 3

Treatment with flavonoids or chlorogenic acid of HCT does not block EV71 infection. (a) HPLC profiling of water extract of HCT. The identity of the water extract of HCT was characterized by HPLC profiling on a Hypersil GOLD column (4.6 mm × 250 mm, 5 μm) and acetonitrile with increasing concentration of 0.1% trifluoroacetic acid as a mobile phase. Hyperoside (peak 1), isoquercitrin (2), quercitrin (3), and quercetin (4) were used as standards. (b) Flavonoids or chlorogenic acid in HCT has no antiviral effect against EV71 infection. Vero cells were pretreated with or without quercetin, quercitrin, isoquercitrin (Isoq), hyperoside (Hepe), or chlorogenic acid (Chlo) at indicated concentrations. The cells were then infected with EV71 at an MOI of 0.2 TCID50/cell for 72 hr, and cell viability was measured colorimetrically. Data are presented as mean ± SE of triplicate samples. The results are representative of two independent experiments.