Inhibitory Potential of Phytochemicals on Interleukin-6-Mediated T-Cell Reduction in COVID-19 Patients: A Computational Approach

The search for an antiviral lead molecule to combat the neglected emerging Oropouche virus

Oropouche virus (OROV) is a member of the Peribunyaviridae family and the causative agent of a dengue-like febrile illness transmitted by mosquitoes. Although mild symptoms generally occur, complications such as encephalitis and meningitis may develop. A lack of proper diagnosis, makes it a potential candidate for new epidemics and outbreaks like other known arboviruses such as Dengue, Yellow Fever and Zika virus. The study of natural molecules as potential antiviral compounds is a promising alternative for antiviral therapies. Wedelolactone (WDL) has been demonstrated to inhibit some viral proteins and virus replication, making it useful to target a wide range of viruses. In this study, we report the in silico effects of WDL on the OROV N-terminal polymerase and its potential inhibitory effects on several steps of viral infection in mammalian cells in vitro, which revealed that WDL indeed acts as a potential inhibitor molecule against OROV infection.

Inhibitory effect of food-functioned phytochemicals on dysregulated inflammatory pathways triggered by SARS-CoV-2: a mechanistic review

Inflammatory cascades of the dysregulated inflammatory pathways in COVID-19 can cause excessive production of pro-inflammatory cytokines and chemokines leading to cytokine storm syndrome (CSS). The molecular cascades involved in the pathways may be targeted for discovery of new anti-inflammatory agents. Many plant extracts have been used clinically in the management of COVID-19, however, their immunosuppressive activities were mainly investigated based on in silico activity. Dietary flavonoids of the extracts such as quercetin, luteolin, kaempferol, naringenin, isorhamnetin, baicalein, wogonin, and rutin were commonly identified as responsible for their inhibitory effects. The present review critically analyzes the anti-inflammatory effects and mechanisms of phytochemicals, including dietary compounds against cytokine storm (CS) and hyperinflammation via inhibition of the altered inflammatory pathways triggered by SARS-CoV-2, published since the emergence of COVID-19 in December 2019. Only a few phytochemicals, mainly dietary compounds such as nanocurcumin, melatonin, quercetin, 6-shagoal, kaempferol, resveratrol, andrographolide, and colchicine have been investigated either in in silico or preliminary clinical studies to evaluate their anti-inflammatory effects against COVID-19. Sufficient pre-clinical studies on safety and efficacy of anti-inflammatory effects of the phytochemicals must be performed prior to proper clinical studies to develop them into therapeutic adjuvants in the prevention and treatmemt of COVID-19 symptoms.

Acridones as promising drug candidates against Oropouche virus

Oropouche virus (OROV) is an emerging vector-borne arbovirus found in South America that causes Oropouche fever, a febrile infection similar to dengue fever. It has a high epidemic potential, causing illness in over 500,000 cases diagnosed since the virus was first discovered in 1955. Currently, the prevention of human viral infection depends on vaccination, but availability for many viruses is limited, and they are classified as neglected viruses. At present, there are no vaccines or antiviral treatments available. An alternative approach to limiting the spread of the virus is to selectively disrupt viral replication mechanisms. Here, we demonstrate the inhibitory effect of acridones, which efficiently inhibited viral replication by 99.9 % in vitro. To evaluate possible mechanisms of action, we conducted tests with dsRNA, an intermediate in virus replication, as well as MD simulations, docking, and binding free energy analysis. The results showed a strong interaction between FAC21 and the OROV endonuclease, which possibly limits the interaction of viral RNA with other proteins. Therefore, our results suggest a dual mechanism of antiviral action, possibly caused by ds-RNA intercalation. In summary, our findings demonstrate that a new generation of antiviral drugs could be developed based on the selective optimization of molecules.

Humulus lupus extract rich in xanthohumol improves the clinical course in critically ill COVID-19 patients

BACKGROUND

The systemic inflammatory response following severe COVID-19 is associated with poor outcomes. Several anti-inflammatory medications have been studied in COVID-19 patients. Xanthohumol (Xn), a natural extract from hop cones, possesses strong anti-inflammatory and antioxidative properties. The aim of this study was to analyze the effect of Xn on the inflammatory response and the clinical outcome of COVID-19 patients.

METHODS

Adult patients treated for acute respiratory failure (PaO₂/FiO₂ less than 150) were studied. Patients were randomized into two groups: Xn - patients receiving adjuvant treatment with Xn at a daily dose of 4.5 mg/kg body weight for 7 days, and C - controls. Observations were performed at four time points: immediately after admission to the ICU and on the 3rd, 5th, and 7th days of treatment. The inflammatory response was assessed based on the plasma IL-6 concentration, neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), C-reactive protein (CRP) and D-dimer levels. The mortality rate was determined 28 days after admission to the ICU.

RESULTS

Seventy-two patients were eligible for the study, and 50 were included in the final analysis. The mortality rate was significantly lower and the clinical course was shorter in the Xn group than in the control group (20% vs. 48%, p < 0.05, and 9 ± 3 days vs. 22 ± 8 days, p < 0.001). Treatment with Xn decreased the plasma IL-6 concentration (p < 0.01), D-dimer levels (p < 0.05) and NLR (p < 0.01) more significantly than standard treatment alone.

CONCLUSION

Adjuvant therapy with Xn appears to be a promising anti-inflammatory treatment in COVID-19 patients.

AI-driven Discovery of Celecoxib and Dexamethasone for Exploring their Mode of Action as Human Interleukin (IL-6) Inhibitors to Treat COVID-19-induced Cytokine Storm in Humans

BACKGROUND

In the case of COVID-19 patients, it has been observed that the immune system of the infected person exhibits an extreme inflammatory response known as cytokine release syndrome (CRS) where the inflammatory cytokines are swiftly produced in quite large amounts in response to infective stimuli. Numerous case studies of COVID-19 patients with severe symptoms have documented the presence of higher plasma concentrations of human interleukin-6 (IL-6), which suggests that IL-6 is a crucial factor in the pathophysiology of the disease. In order to prevent CRS in COVID-19 patients, the drugs that can exhibit binding interactions with IL-6 and block the signaling pathways to decrease the IL-6 activity may be repurposed.

METHODS

This research work focused on molecular docking-based screening of the drugs celecoxib (CXB) and dexamethasone (DME) to explore their potential to interact with the binding sites of IL-6 protein and reduce the hyper-activation of IL-6 in the infected personnel.

RESULTS

Both of the drugs were observed to bind with the IL-6 (IL-6 receptor alpha chain) and IL-6Rα receptor with the respective affinities of -7.3 kcal/mol and -6.3 kcal/mol, respectively, for CXB and DME. Moreover, various types of binding interactions of the drugs with the target proteins were also observed in the docking studies. The dynamic behaviors of IL-6/IL-6Rα in complex with the drugs were also explored through molecular dynamics simulation analysis. The results indicated significant stabilities of the acquired drug-protein complexes up to 100 ns.

CONCLUSION

The findings of this study have suggested the potential of the drugs studied to be utilized as antagonists for countering CRS in COVID-19 ailment. This study presents the studied drugs as promising candidates both for the clinical and pre-clinical treatment of COVID-19.

An Evaluation of the Novel Biological Properties of Diterpenes Isolated from Plectranthus ornatus Codd. In Vitro and In Silico

Plectranthus ornatus Codd, the genus Plectranthus of the Lamiaceae family, has been used as traditional medicine in Africa, India and Australia. Pharmacological studies show the use of this plant to treat digestive problems. In turn, leaves were used for their antibiotic properties in some regions of Brazil to treat skin infections. The present study examines the anti-inflammatory, antioxidant and cytotoxic effects of the halimane and labdane diterpenes (11R*,13E)-11-acetoxyhalima-5,13-dien-15-oic acid (HAL) and 1α,6β-diacetoxy-8α,13R*-epoxy-14-labden-11-one (PLEC) and the forskolin-like 1:1 mixture of 1,6-di-O-acetylforskolin and 1,6-di-O-acetyl-9-deoxyforskolin (MRC) isolated from P. ornatus on lung (A549) and leukemia (CCRF-CEM) cancer cell lines, and on normal human retinal pigment epithelial (ARPE-19) cell line in vitro. Additionally, molecular docking and computational approaches were used. ADMET properties were analysed through SwissADME and proTox-II—Prediction. The results indicate that all tested compounds significantly reduced the viability of the cancer cells and demonstrated no cytotoxic effects against the non-neoplastic cell line. The apoptosis indicators showed increased ROS levels for both the tested A549 and CCRF-CEM cancer cell lines after treatment. Furthermore, computational studies found HAL to exhibit moderate antioxidant activity. In addition, selected compounds changed mitochondrial membrane potential (MMP), and increased DNA damage and mitochondrial copy number for the CCRF-CEM cancer cell line; they also demonstrated anti-inflammatory effects on the ARPE-19 normal cell line upon lipopolysaccharide (LPS) treatment, which was associated with the modulation of IL-6, IL-8, TNF-α and GM-CSF genes expression. Docking studies gave indication about the lowest binding energy for 1,6-di-O-acetylforskolin docked into IL-6, TNF-α and GM-CSF, and 1,6-di-O-acetyl-9-deoxyforskolin docked into IL-8. The ADMET studies showed drug-likeness properties for the studied compounds. Thus, halimane and labdane diterpenes isolated from P. ornatus appear to offer biological potential; however, further research is necessary to understand their interactions and beneficial properties.

In Silico Analysis Using SARS-CoV-2 Main Protease and a Set of Phytocompounds to Accelerate the Development of Therapeutic Components against COVID-19

SARS-CoV-2, the virus that caused the widespread COVID-19 pandemic, is homologous to SARS-CoV. It would be ideal to develop antivirals effective against SARS-CoV-2. In this study, we chose one therapeutic target known as the main protease (Mpro) of SARS-CoV-2. A crystal structure (Id: 6LU7) from the protein data bank (PDB) was used to accomplish the screening and docking studies. A set of phytocompounds was used for the docking investigation. The nature of the interaction and the interacting residues indicated the molecular properties that are essential for significant affinity. Six compounds were selected, based on the docking as well as the MM-GBSA score. Pentagalloylglucose, Shephagenin, Isoacteoside, Isoquercitrin, Kappa-Carrageenan, and Dolabellin are the six compounds with the lowest binding energies (−12 to −8 kcal/mol) and show significant interactions with the target Mpro protein. The MMGBSA scores of these compounds are highly promising, and they should be investigated to determine their potential as Mpro inhibitors, beneficial for COVID-19 treatment. In this study, we highlight the crucial role of in silico technologies in the search for novel therapeutic components. Computational biology, combined with structural biology, makes drug discovery studies more rigorous and reliable, and it creates a scenario where researchers can use existing drug components to discover new roles as modulators or inhibitors for various therapeutic targets. This study demonstrated that computational analyses can yield promising findings in the search for potential drug components. This work demonstrated the significance of increasing in silico and wetlab research to generate improved structure-based medicines.