Water Extract ofGlycyrrhiza uralensisInhibited Enterovirus 71 in a Human Foreskin Fibroblast Cell Line

Abstract

Human infection by enterovirus type 71 (EV71) can cause life-threatening meningo-encephalitis. Currently, there is no effective anti-EV71 therapy available. Since EV71 infection commonly involves skin lesions, we tested our hypothesis that water extract of Glycyrrhiza uralensis (G. uralensis) could inhibit the cytopathic effects of EV71 in a human foreskin cell line by using an XTT-based method. Our results showed that the water extract of G. uralensis at 3,000 microg/ml has only 30% cytotoxicity on host cells, and furthermore, that the water extract of G. uralensis at 0.1 microg/ml could effectively protect host cells against EV71 infection (p < 0.0001). The half maximal inhibitory concentration (IC(50)) was 0.056 microg/ml with a selective index greater than 50,000. The water extract of G. uralensis exerted its effects not only by preventing viral attachment (p < 0.0001), but also by inhibiting the penetration of the virus (p < 0.0001). EV71 infection caused cells to produce significant amounts of IFN-beta (p = 0.0003). However, the anti-EV71 activity of the water extract of G. uralensis was not mediated by IFN. In conclusion, the water extract of G. uralensis possesses potent anti-EV71 effects with less cytotoxicity. Its low IC(50) and high 50% cytotoxic concentration (CC(50)) values suggest that it is a promising anti-EV71 agent.

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

“…Many plants and their components have been reported to have anti-EV71 activity (Kuo et al, 2009;Lin et al, 2009;Tsai et al, 2011;Zhu et al, 2011). As a traditional Chinese herbal medicine, the aerial part of S. chinensis (Lour.)…”

Antiviral Ability ofKalanchoe gracilisLeaf Extract against Enterovirus 71 and Coxsackievirus A16

“…Also, IC 50 value of K. gracilis leaf extract against EV71 and CVA16 were 35.88  μ g/mL and 42.91  μ g/mL, respectively (Figure 4), while the therapeutic index of K. gracilis leaf extract against EV71 and CVA16 ranged from 23 to 28. A literature survey indicated some extracts of Chinese herbs exhibiting anti-EV71 activities in vitro , such as Houttuynia cordata Thunb (IC 50 = 125.9  μ g/mL) [38], Woodfordia fruticosa Kurz (IC 50 = 1.2  μ g/mL) [34], Salvia miltiorrhiza (IC 50 = 585  μ g/mL) [39], Pueraria lobata (IC 50 = 0.028  μ g/mL) [40], and Glycyrrhiza uralensis (IC 50 = 0.056  μ g/mL) [41]. Therefore, K. gracilis leaf extract exhibited moderately potent anti- EV71 and CVA16 activities.…”

Effects of Herbal Medicinal Formulas on Suppressing Viral Replication and Modulating Immune Responses

“…A. membranaceus, which has been frequently used with other TCMs in treatments for strengthening human immune responses (Xue et al, 2008), has been demonstrated to have antitumor effects in vitro and in vivo (Cho and Leung, 2007) and enhance the immunotherapeutic effects of type 1 diabetic mice (Li et al, 2007). The effects of G. uralensis include suppressing RANTES secretion by influenza H1N1 virus-infected A549 epithelial cells (Ko et al, 2006), inhibiting tumor growth without severe cytotoxicity to normal cells (Chung et al, 2001), and modulating immunity in macrophages and fibroblasts (Cheng et al, 2008;Kuo et al, 2009). C. foetida has versatile medical applications and is prescribed to ease uncomfortable feelings or medical symptoms caused by hot flashes, diabetes, inflammatory, HIV or malaria infection, osteoporosis, and vasoactive complications (Li and Yu, 2006).…”