In vitro study on efficacy of SKF7, a Malaysian medicinal plant product against SARS-CoV-2.

BACKGROUND

In early 2020, COVID-19 pandemic has mobilized researchers in finding new remedies including repurposing of medicinal plant products focusing on direct-acting antiviral and host-directed therapies. In this study, we performed an in vitro investigation on the standardized Marantodes pumilum extract (SKF7) focusing on anti-SARS-CoV-2 and anti-inflammatory activities.

METHODS

Anti-SARS-CoV-2 potential of the SKF7 was evaluated in SARS-CoV-2-infected Vero E6 cells and SARS-CoV-2-infected A549 cells by cytopathic effect-based assay and RT-qPCR, respectively. Target based assays were performed on the SKF7 against the S1-ACE2 interaction and 3CL protease activities. Anti-inflammatory activity of the SKF7 was evaluated by nitric oxide inhibitory and TLR2/TLR4 receptor blocker assays.

RESULTS

The SKF7 inhibited wild-type Wuhan (EC of 21.99 µg/mL) and omicron (EC of 16.29 µg/mL) SARS-CoV-2 infections in Vero-E6 cells. The SKF7 also inhibited the wild-type SARS-CoV-2 infection in A549 cells (EC value of 6.31 µg/mL). The SKF7 prominently inhibited 3CL protease activity. The SKF7 inhibited the LPS induced-TLR4 response with the EC of 16.19 µg/mL.

CONCLUSIONS

In conclusion, our in vitro study highlighted anti-SARS-CoV-2 and anti-inflammatory potentials of the SKF7. Future pre-clinical in vivo studies focusing on antiviral and immunomodulatory potentials of the SKF7 in affecting the COVID-19 pathogenesis are warranted.