Identifying the Anti-MERS-CoV and Anti-HcoV-229E Potential Drugs from the Ginkgo biloba Leaves Extract and Its Eco-Friendly Synthesis of Silver Nanoparticles

Abstract

The present study aimed to estimate the antiviral activities of Ginkgo biloba (GB) leaves extract and eco-friendly free silver nanoparticles (Ag NPs) against the MERS-CoV (Middle East respiratory syndrome-coronavirus) and HCoV-229E (human coronavirus 229E), as well as isolation and identification of phytochemicals from GB. Different solvents and high-performance liquid chromatography (HPLC) were used to extract and identify flavonoids and phenolic compounds from GB leaves. The green, silver nanoparticle synthesis was synthesized from GB leaves aqueous extract and investigated for their possible effects as anti-coronaviruses MERS-CoV and HCoV-229E using MTT assay protocol. To verify the synthesis of Ag NPs, several techniques were employed, including X-ray diffraction (XRD), scan, transmission electron microscopy, FT-IR, and UV-visible spectroscopy. The highest contents of flavonoids and phenolic compounds were recorded for acetone, methanol, and ethanol as mixtures with water, in addition to pure water. HPLC flavonoids were detected as apegenin, luteolin, myricetin, and catechin, while HPLC phenolic compounds were pyrogallol, caffeic acid, gallic acid, and ellagic acid. In addition, our results revealed that Ag NPs were produced through the shift from yellow to dark brown. TEM examination of Ag NPs revealed spherical nanoparticles with mean sizes ranging from 5.46 to 19.40 nm and an average particle diameter of 11.81 nm. A UV-visible spectrophotometric investigation revealed an absorption peak at λ max of 441.56 nm. MTT protocol signified the use of GB leaves extract as an anti-coronavirus to be best from Ag NPs because GB extract had moderate anti-MERS-CoV with SI = 8.94, while had promising anti-HCov-229E, with an SI of 21.71. On the other hand, Ag NPs had a mild anti-MERS-CoV with SI = 4.23, and a moderate anti-HCoV-229E, with an SI of 7.51.

Keywords: Ginkgo biloba; anti-coronavirus; natural products; silver nanoparticles.

Figure 1

HPLC chromatogram of flavonoids from GB leaves.

Figure 2

HPLC chromatogram of phenolics from GB leaves.

Figure 3

Chemical structures of the HPLC-detected flavonoids in GB leaves (https://pubchem.ncbi.nlm.nih.gov), accessed on 15 April 2022.

Figure 3

Chemical structures of the HPLC-detected flavonoids in GB leaves (https://pubchem.ncbi.nlm.nih.gov), accessed on 15 April 2022.

Figure 4

Chemical structures of the HPLC-detected phenolics in GB leaves (https://pubchem.ncbi.nlm.nih.gov), accessed on 15 April 2022.

Figure 5

The UV–Vis spectroscopy of (a) the GB extract and as-biofabricated Ag NPs and (b) Ag NPs show good stability at regular intervals (for 3 days).

Figure 6

The as-biofabricated Ag NPs X-ray diffractogram from the GB leaf extracts.

Figure 7

FT-IR spectra of the GB extract and as-biofabricated Ag NPs.

Figure 8

The as-biofabricated Ag NPs: (A) SEM image; (B) particle size distribution.

Figure 9

The as-biofabricated Ag NPs: (A) TEM image; (B) the distribution of particle size.

Figure 10

Zeta potential data of bio–fabricated Ag NPs using GB leaf extract.

Figure 11

The anti–coronavirus activity of GB leaves extracts against MERS and 229E viruses using Vero cell lines. (A) Cytotoxicity; (B) antiviral activity; (C) CC50; (D) IC50 of the extract against MERS; (E) IC50 of the extract against 229E.

Figure 12

Anti–coronavirus activity of free silver nanoparticles (Ag NPs) against MERS and 229E viruses using the Vero cell line. (A) cytotoxicity; (B) antiviral activity; (C) CC50; (D) IC50 of the extract against MERS; (E) IC50 of the extract against 229E.