Characterization of the inhibitory effect of an extract of Prunella vulgaris on Ebola virus glycoprotein (GP)-mediated virus entry and infection

Abstract

Currently, no approved antiviral therapeutic is available for treatment or prevention of Ebola virus (EBOV) infection. In this study, we characterized an EBOV-glycoprotein (GP) pseudotyped HIV-1-based vector system in different cell cultures, including human umbilical vein endothelial cells (HUVECs) and human macrophages, for the screening of anti-EBOV-GP agent(s). Based on this system, we demonstrated that an aqueous extract (CHPV) from the Chinese herb Prunella vulgaris displayed a potent inhibitory effect on EBOV-GP pseudotyped virus (EBOV-GP-V)-mediated infection in various cell lines, including HUVEC and macrophage. In addition, our results indicated that CHPV was able to block an eGFP-expressing Zaire ebola virus (eGFP-ZEBOV) infection in VeroE6 cells. The anti-EBOV activity of CHPV was exhibited in a dose-dependent manner. At a 12.5 μg/ml concentration, the CHPV showed a greater than 80% inhibition of EBOV-GP-V and eGFP-EBOV infections. Likewise, our studies suggested that the inhibitory effect of CHPV occurred by binding directly to EBOV-GP-Vs and blocking the early viral events. Interestingly, our results have shown that CHPV was able to enhance the anti-EBOV activity of the monoclonal antibody MAb 2G4 against EBOV-GP. Overall, this study provides evidence that CHPV has anti-EBOV activity and may be developed as a novel antiviral approach against EBOV infection.

Antibody-dependent-cellular-cytotoxicity-inducing antibodies significantly affect the post-exposure treatment of Ebola virus infection

“…Its efficacy is also similar to the potent neutralizing antibody mAb114, which has an IC 50 value of 0.09 μg/ml in the same pseudovirus neutralization cellular assay, a maximal ADCC activity of 0.03 μg/ml, and is considered to be the most potent neutralizing activity described so far1532. This is the first study to define antibodies as either neutralizing or ADCC-inducing antibodies and to describe their use in anti-EBOV prevention or treatment strategies based on their in vitro neutralizing or ADCC-inducing properties.…”

The Antiviral, Anti-Inflammatory Effects of Natural Medicinal Herbs and Mushrooms and SARS-CoV-2 Infection

“…In the same study, a "time-of-addition" study was performed in order to investigate the CHPV anti-EBOV mechanism of action. The results obtained concluded that the inhibitory effect of CHPV occurred via binding directly to EBOV-GP-Vs and possibly suppressing virus attachment through targeting the viral GP protein, thus blocking the early viral events [28]. Previous studies investigating PV found that aqueous extracts from this herb had the potential to decrease the replication of herpes simplex virus (HSV) by directly preventing the virus to bind to cells as well as having the capability to inhibit HIV-1 infection by preventing viral attachment to CD4+ T cell receptor [29,30].…”

Identification of Ellagic Acid from Plant Rhodiola rosea L. as an Anti-Ebola Virus Entry Inhibitor

“…R. rosea extract had an IC 50 value of 0.25 µg/mL in the pseudovirus infection assay and an IC 50 value of 3.9 µg/mL in an infectious EBOV infection assay, respectively, while it inhibited Marburg virus with an IC 50 value of 4.0 µg/mL in pseudovirus assay and an IC 50 value of ~25 µg/mL in infectious virus assay, respectively ( Figure 2 and Figure 4 ). The anti-EBOV activity of R. rosea is better than that (IC 50 ~6.25 µg/mL) of the best reported TCM Prunella vulgaris extract so far [ 40 ].…”