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.

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.

Ginkgolides and bilobalide for treatment of Alzheimer's disease and COVID-19: potential mechanisms of action.

Alzheimer's disease (AD) is an irreversible degenerative illness of the central nervous system with characteristic histological alterations, known as amyloid plaques and neurofibrillary tangles (NFT). Aggregation of plaques and tangles in the brain induces neurotoxicity and synaptic dysfunction, eventually contributing to neuronal cell death and neurodegeneration. Recent studies have revealed that COVID-19 has a great impact on the development of AD, directly or indirectly, by facilitating the accumulation of amyloid plaques, causing altered functional brain integrity or increasing the phosphorylation rate of tau protein. As two important bioactive components of Ginkgo biloba extract (GbE), ginkgolides and bilobalide (BB) have been reported to show neuroprotective effects in AD via multiple mechanisms such as anti-excitotoxicity, anti-inflammatory and anti-oxidative activities. Intriguingly, ginkgolides and BB also seem to demonstrate antiviral properties against COVID-19 by inhibiting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) main protease. Herein, we review studies on the neuroprotective and antiviral mechanisms of ginkgolides and bilobalide, as well as their therapeutic potential against AD and COVID-19.

Alleviation of Post-COVID-19 Cognitive Deficits by Treatment with EGb 761®: A Case Series.

BACKGROUND Cognitive symptoms persisting longer than 3 months after infection, such as memory loss, or difficulties concentrating, have been reported in up to one-third of patients after COVID-19. Evidence-based therapeutic interventions to treat post-COVID-19 symptoms (also called "Long-COVID symptoms") have not yet been established, and the treating physicians must rely on conjecture to help patients. Based on its mechanism of action and its efficacy in treating cognitive impairment, as well as its good tolerability, the Ginkgo biloba special extract EGb 761 has been suggested as a remedy to alleviate cognitive post-COVID-19 symptoms. In many studies, EGb 761 has been demonstrated to protect endothelial cells, to have potent anti-inflammatory effects, and to enhance neuroplasticity. CASE REPORT Here, we report for the first time the application of EGb 761 in the therapy of post-COVID-19-related cognitive deficits. Three women and 2 men, aged 26 to 59 years (average age 34.6 years), presented with concentration and attention deficits, cognitive deficiencies, and/or fatigue 9-35 weeks after infection. A daily dose of 2×80 mg of EGb 761 did not cause any detectable adverse effects, and it substantially improved or completely restored cognitive deficits and, when initially present, also other symptoms, such as fatigue and hyposmia, within an observation period of up to 6 months. CONCLUSIONS Our observations support the hypothesis that EGb 761 might be a low-risk treatment option for post-COVID-19 patients with cognitive symptoms. Moreover, we derive recommendations for randomized controlled clinical trials to confirm efficacy in that indication.

Ginkgo biloba in the management of the COVID-19 severity.

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection is linked with inflammatory disorders and the development of oxidative stress in extreme cases. Therefore, anti-inflammatory and antioxidant drugs may alleviate these complications. Ginkgo biloba L. folium extract (EGb) is a herbal medicine containing various active constituents. This review aims to provide a critical discussion on the potential role of EGb in the management of coronavirus disease 2019 (COVID-19). The antiviral effect of EGb is mediated by different mechanisms, including blocking SARS-CoV-2 3-chymotrypsin-like protease that provides trans-variant effectiveness. Moreover, EGb impedes the development of pulmonary inflammatory disorders through the diminution of neutrophil elastase activity, the release of proinflammatory cytokines, platelet aggregation, and thrombosis. Thus, EGb can attenuate the acute lung injury and acute respiratory distress syndrome in COVID-19. In conclusion, EGb offers the potential of being used as adjuvant antiviral and symptomatic therapy. Nanosystems enabling targeted delivery, personalization, and booster of effects provide the opportunity for the use of EGb in modern phytotherapy.

Discovery of naturally occurring inhibitors against SARS-CoV-2 3CLpro from Ginkgo biloba leaves via large-scale screening.

3-Chymotrypsin-like protease (3CLpro) is a virally encoded main proteinase that is pivotal for the viral replication across a broad spectrum of coronaviruses. This study aims to discover the naturally occurring SARS-CoV-2 3CLpro inhibitors from herbal constituents, as well as to investigate the inhibitory mechanism of the newly identified efficacious SARS-CoV-2 3CLpro inhibitors. Following screening of the inhibitory potentials of eighty herbal products against SARS-CoV-2 3CLpro, Ginkgo biloba leaves extract (GBLE) was found with the most potent SARS-CoV-2 3CLpro inhibition activity (IC50 = 6.68 µg/mL). Inhibition assays demonstrated that the ginkgolic acids (GAs) and the bioflavones isolated from GBLE displayed relatively strong SARS-CoV-2 3CLpro inhibition activities (IC50 < 10 µM). Among all tested constituents, GA C15:0, GA C17:1 and sciadopitysin displayed potent 3CLpro inhibition activities, with IC50 values of less than 2 µM. Further inhibition kinetic studies and docking simulations clearly demonstrated that two GAs and sciadopitysin strongly inhibit SARS-CoV-2 3CLprovia a reversible and mixed inhibition manner. Collectively, this study found that both GBLE and the major constituents in this herbal product exhibit strong SARS-CoV-2 3CLpro inhibition activities, which offer several promising leading compounds for developing novel anti-COVID-19 medications via targeting on 3CLpro.

Evidence that Ginkgo Biloba could use in the influenza and coronavirus COVID-19 infections.

Coronavirus COVID-19 pandemic invades the world. Public health evaluates the incidence of infections and death, which should be reduced and need desperately quarantines for infected individuals. This article review refers to the roles of Ginkgo Biloba to reduce the risk of infection in the respiratory tract, the details on the epidemiology of corona COVID-19 and influenza, and it highlights how the Ginko Biloba could have been used as a novel treatment.Ginkgo Biloba can reduce the risk of infection by several mechanisms; these mechanisms involve Ginkgo Biloba contains quercetin and other constituents, which have anti-inflammatory and immune modulator effects by reducing pro-inflammatory cytokines concentrations. Cytokines cause inflammation which have been induced the injuries in lung lining.Some observational studies confirmed that Ginkgo Biloba reduced the risk of asthma, sepsis and another respiratory disease as well as it reduced the risk of cigarette smoking on respiratory symptoms. While other evidences suggested the characters of Ginkgo Biloba as an antivirus agent through several mechanisms. Ginkgolic acid (GA) can inhibit the fusion and synthesis of viral proteins, thus, it inhibit the Herpes Simplex Virus type1 (HSV-1), genome replication in Human Cytomegalovirus (HCMV) and the infections of the Zika Virus (ZIKV). Also, it inhibits the wide spectrum of fusion by inhibiting the three types of proteins that have been induced fusion as (Influenza A Virus [IAV], Epstein Barr Virus [EBV], HIV and Ebola Virus [EBOV]).The secondary mechanism of GA targeting inhibition of the DNA and protein synthesis in virus, greatly have been related to its strong effects, even afterward the beginning of the infection, therefore, it potentially treats the acute viral contaminations like (Measles and Coronavirus COVID-19). Additionally, it has been used topically as an effective agent on vigorous lesions including (varicella-zoster virus [VZV], HSV-1 and HSV-2). Ginkgo Biloba may be useful for treating the infected people with coronavirus COVID-19 through its beneficial effect. To assess those recommendations should be conducted with random control trials and extensive population studies.