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

Abstract

Enterovirus 71 (EV71) and coxsackievirus A16 (CVA16) are the causative agents of hand, foot, and mouth disease (HFMD). During recent epidemics of HFMD in China, medicinal herbals and preparations containing herbal extracts have demonstrated therapeutic efficacy with relative safety profiles. There have been no microbiological studies to validate their usefulness for HFMD. We selected 12 commonly used herbs for HFMD from government recommended guidelines as well as published reports and tested for their antiviral activity and anti-inflammatory activity. A water extract of Houttuynia cordata Thunb. (HCT) inhibited EV71 infection significantly and was marginally active against CVA16 infection. The IC50 (concentration to have 50% inhibitory effect) values of HCT against a Fuyang strain and a BrCr strain of EV71 were determined at 8.9 μg/mL and 20.6 μg/mL, respectively. Mentha haplocalyx Briq. (MHB) water extract was active against CVA16, with an IC50 value of 70.3 μg/mL. The extract did not exhibit activity against EV71 infection. Although the majority of the extracts showed no activity against viral infection, several extracts demonstrated activity in blocking proinflammatory response by viral infection. This study therefore validates the effectiveness of Chinese herbs for HFMD since some formulations containing the correct combination of the herbs can block viral replication as well as proinflammatory response of HFMD.

Saururus chinensis (Lour.) Baill blocks enterovirus 71 infection by hijacking MEK1–ERK signaling pathway

“…The antiviral activity was evaluated by methods of crystal violet staining, secondary infection, time-of-drug addition assay and virucidal assay as previously described (Chen et al, 2013). IC 50 was defined as the concentration of SCB that is necessary for 50% inhibition of the virus-induced CPE.…”

“…It instead caused cell cycle arrest at 300 lg/mL, a maximal non-toxic concentration to Vero cells as determined in this study. Since there are no authenticated inhibition drugs for EV71 and HCT was previously reported having anti-EV71 activity (Chen et al, 2013), HCT at 40 lg/mL was used as a positive control for blocking EV71 infection in this study.…”

“…cDNA was synthesized using the Primescript RT reagent kit (TAKARA, Shiga, Japan) and then amplified by using gene-specific primers and Taq Polymerase (TaKaRa, Tokyo, Japan). Real-time PCR was conducted as previously described (Chen et al, 2013). Data were calculated following the 2 ÀDDCt method (Livak and Schmittgen, 2001).…”

“…Data were calculated following the 2 ÀDDCt method (Livak and Schmittgen, 2001). The primers for IL-6 and GAPDH were used as previously described (Chen et al, 2013). The primer sequences for VP1: 5 0 -ATGTCACC TGCGAGTGCTTAT and 5 0 -GAACGTGCCCA TCTGGCTTGTTCCTCAC TACT.…”

Antiviral Activity of Paulownia tomentosa against Enterovirus 71 of Hand, Foot, and Mouth Disease

“…In a previous study, we performed a laboratory evaluation of most commonly used herbs for their antiviral activity against HFMD and identified several herbs with antiviral activity. 3) In this report, we studied the antiviral activity of Paulownia tomentosa (THUNB.) STEUD.…”