Figure 1Phylogenetic analysis based on full-length genomic sequences of a CVA16 isolate from a patient with hand, foot, and mouth disease. Nucleotide sequences were analyzed by the neighbor-joining method. The numbers at the branches indicate the bootstrap values for 1000.
Figure 2Antiviral activity of medicinal plant extracts against CVA16 in Vero cells. (A) Vero cells were infected with CVA16 and treated with the indicated concentrations (0.4–50 μg/mL) of medicinal plant extracts for 48 hours. Antiviral activity was assessed using a cytopathic effects reduction assay. Results are presented as the mean percentage values obtained from three independent experiments carried out in triplicate ± standard deviation. (B) Vero cells were infected with CVA16 and treated with various concentrations of Cornus officinalis, Acer triflorum, Pulsatilla koreana, and Clematis heracleifolia var. davidiana Hemsl for 48 hours. CVA16 5′NCR genes were quantitatively measured using real-time reverse transcription polymerase chain reaction.
Figure 3Morphological assessment of CVA16-infected Vero cells following treatment with four medicinal plant extracts. CVA16-infected and uninfected Vero cells were treated with 50 μg/mL medicinal plant extracts. After staining of viable cells with sulforhodamine B, cell morphology was assessed by microscopy. (A) Untreated, (B) uninfected cells treated with Cornus officinalis, (C) Acer triflorum, (D) Pulsatilla koreana, (E) Clematis heracleifolia var. davidiana Hemsl, (F) untreated CVA16-infected cells, (G) CVA16-infected cells treated with Cornus officinalis, (H) CVa16-infected cells treated with Acer triflorum, (I) CVA16-infected cells treated with Pulsatilla koreana, and (J) CVA16-infected cells treated with Clematis heracleifolia var. davidiana Hemsl.
Table 1Antiviral activity of four medicinal plant extracts against CVA16.
Medicinal plant extract |
Coxsackievirus A16
|
CC50
|
IC50
|
TI |
Cornus officinalis
|
> 50 |
32.9 ± 1.30 |
1.52 |
Acer triflorum
|
> 50 |
32.3 ± 1.67 |
1.55 |
Pulsatilla koreana
|
> 50 |
1.51 ± 0.05 |
33.11 |
Clematis heracleifolia var. davidiana Hemsl |
> 50 |
2.55 ± 1.06 |
19.61 |