Antigen-encapsulating host extracellular vesicles derived from Salmonella-infected cells stimulate pathogen-specific Th1-type responses in vivo.

Salmonella Typhimurium is a causative agent of nontyphoidal salmonellosis, for which there is a lack of a clinically approved vaccine in humans. As an intracellular pathogen, Salmonella impacts many cellular pathways. However, the intercellular communication mechanism facilitated by host-derived small extracellular vesicles (EVs), such as exosomes, is an overlooked aspect of the host responses to this infection. We used a comprehensive proteome-based network analysis of exosomes derived from Salmonella-infected macrophages to identify host molecules that are trafficked via these EVs. This analysis predicted that the host-derived small EVs generated during macrophage infection stimulate macrophages and promote activation of T helper 1 (Th1) cells. We identified that exosomes generated during infection contain Salmonella proteins, including unique antigens previously shown to stimulate protective immune responses against Salmonella in murine studies. Furthermore, we showed that host EVs formed upon infection stimulate a mucosal immune response against Salmonella infection when delivered intranasally to BALB/c mice, a route of antigen administration known to initiate mucosal immunity. Specifically, the administration of these vesicles to animals stimulated the production of anti-Salmonella IgG antibodies, such as anti-OmpA antibodies. Exosomes also stimulated antigen-specific cell-mediated immunity. In particular, splenic mononuclear cells isolated from mice administered with exosomes derived from Salmonella-infected antigen-presenting cells increased CD4+ T cells secreting Th1-type cytokines in response to Salmonella antigens. These results demonstrate that small EVs, formed during infection, contribute to Th1 cell bias in the anti-Salmonella responses. Collectively, this study helps to unravel the role of host-derived small EVs as vehicles transmitting antigens to induce Th1-type immunity against Gram-negative bacteria. Understanding the EV-mediated defense mechanisms will allow the development of future approaches to combat bacterial infections.

Sesamol attenuates bleomycin-induced pulmonary toxicity and fibrosis in experimental animals.

Sesamol, a lignan obtained from roasted seeds of Sesamum indicum, has high antioxidant and anti-inflammatory activity. In this study, we have investigated the effect of sesamol on Bleomycin (BLM) induced pulmonary toxicity as well as fibrosis in Wistar rats. Lung toxicity was induced by administration of BLM, 0.015 U/g ip, twice weekly for 28 days whereas lung fibrosis was induced by BLM, 0.015 U/g ip, every 5th day for 49 days. Sesamol administration was started 7 days before first dose of BLM in both the models. It was observed that sesamol 50 mg/kg most effectively attenuated pulmonary toxicity by reducing oxidative stress, inflammation and apoptosis. This dose was further evaluated for its anti-fibrotic effect. It was observed that there was a significant reduction in fibrosis. Lung collagen content was markedly reduced. Furthermore, expression of pro-fibrotic proteins, TGF-ß/SMAD and α-SMA, was reduced and that of anti-fibrotic protein, AMPK, was markedly increased. Even though the combination of sesamol with pirfenidone exhibited no additional protection than either drug alone, it is evident from our study that our test drug, sesamol is comparable in efficacy to pirfenidone. Thus, sesamol has promising therapeutic potential in treatment of pulmonary toxicity and fibrosis.

Discovery and in silico evaluation of aminoarylbenzosuberene molecules as novel checkpoint kinase 1 inhibitor determinants.

Checkpoint kinase 1 (CHK1) is an essential kinase with a critical function in cell cycle arrest. Several potent inhibitors targeting CHK1 have been published, but most of them have failed in clinical trials. Acknowledging the emerging consequence of CHK1 inhibitors in medication of cancer, there is a demand for widening the chemical range of CHK1 inhibitors. In this research, we considered a set of in-house plant based semi-synthetic aminoarylbenzosuberene molecules as potential CHK1 inhibitors. Based on a combined computational research that consolidates molecular docking and binding free energy computations we recognized the crucial determinants for their receptor binding. The drug likeness of these molecules were also scrutinized based on their toxicity and bioavailibilty profile. The computational strategy indicates that the Bch10 could be regarded as a potential CHK1 inhibitor in comparison with top five co-crystallize molecules. Bch10 signifies a promising outlet for the development of potent inhibitors for CHK1.

Tafenoquine for Plasmodium vivax malaria: Concerns regarding efficacy & safety.

Plasmodium vivax (P. vivax) malaria is a major problem in various countries such as America, Southeast Asia, Africa and the Eastern Mediterranean. The major barrier in controlling P. vivax malaria is its ability to remain in the liver as a hypnozoite form which is responsible for relapse of P. vivax malaria; hence it is necessary to target both the blood (schizont) as well as the liver (hypnozoite) stages of P. vivax to prevent its relapse. A number of factors limit the use of primaquine (PQ), the currently available therapy for P. vivax (hypnozoite stage), such as haemolysis in glucose-6-phosphate dehydrogenase-deficient patients and being contraindicated in pregnant women. Another problem associated with PQ is the poor adherence rate to the 14-day treatment regimen. Single-dose tafenoquine (TQ), an 8-aminoquinoline, has recently been approved by the U.S. FDA for the treatment of P. vivax malaria along with a blood schizonticidal. TQ is active against all stages of P. vivax lifecycle. In published studies, TQ is considered a better alternative to PQ in terms of adherence, but there are some concerns regarding its safety, efficacy and study designs of trials conducted on TQ. In this context, this review, discusses the potential safety concerns, efficacy data, summary and an appraisal of findings of the important published trials of TQ.

Plant-based analogues identified as potential inhibitor against tobacco mosaic virus: A biosimulation approach.

Benzosuberene compounds with a pyrrolone group adhered to it are compounds extracted from the oils of Cedrus deodara plant, that bear inhibitory capabilities. Tobacco mosaic virus is known to affect crop production every year. The currently known inhibitors against TMV have a weak inhibition effect and also tend to be toxic towards non-target living organisms as well as the environment. Thus, the requirement of non-toxic potent inhibitors is the need of the hour, which led us to test our benzosuberene molecules on the binding site of TMV and check their affinity as well as stability. The non-toxic nature of these molecules has already been experimentally established. Through in-silico analysis involving docking and simulation experiments, we compared the interaction pattern of these ligand molecules with the already present inhibitors. Our investigation proved that the reported ligands (ligands 3, 7, 9, and 17 obtained -177.103, -228.632, -184.134, and - 188.075 kJ/mol binding energies, respectively) interacted with the binding site of TMV much efficiently than the known inhibitors (Ribavirin and Zhao et al. 2020 obtained 121.561 and - 221.393 kJ/mol binding energies, respectively). Moreover, they acquired a stable conformation inside the binding pocket, where a higher number of binding site residues contributed towards interaction. Thus, their structural framework can be optimized for the exploration of their antiviral properties to develop potent botanical viricides against plant virus infection.

A review on interleukins: The key manipulators in rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease associated with weakening of bones and joint pain. It primarily involves autoimmunity, matrix destruction, osteoclastogenesis, inflammation, and angiogenesis. Numerous cellular and humoral components of the immune system are involved in the etiology of diseases; however, the cardinal part is played by the inter-cellular signaling messengers called cytokines. Interleukins is a vaguely defined sub-class of cytokines that are abundantly found in the RA patients. The multifariousness and diversity in the function of the interleukins make them very likely to be associated with the pathogenesis in multiple ways. Nonetheless, the variety in opinions of researchers globally has led to contentious inferences. Ergo, in this review we have amalgamated the views of researchers from the past two decades till date to provide a comprehensive report about the role of interleukins in rheumatoid arthritis.

Molecular mechanisms of flavonoids in myocardial ischemia reperfusion injury: Evidence from in-vitro and in-vivo studies.

OBJECTIVES: Flavonoids are polyphenolic compounds found in a wide range of foods, including fruits, vegetables, tea plants, and other natural products. They have been mainly classified as flavanols, flavonols, flavones, isoflavones, flavanones, and flavanonols. In this comprehensive review, we will discuss preclinical pieces of evidence on the potential of flavonoids for the prevention/treatment of myocardial ischemia-reperfusion (IR) injury. KEY FINDINGS: In-vitro and in-vivo studies have shown that flavonoids play an important role in preventing ischemic heart disease (IHD). They possess strong anti-oxidant, anti-inflammatory, anti-bacterial, anti-thrombotic, anti-apoptotic, and anti-carcinogenic activities. In addition, at a molecular level, flavonoids also modulate various pathways like MAPK, NFκB etc. to confer beneficial effects. SUMMARY: The current review of flavonoids in myocardial ischemia-reperfusion injury furnishes updated information that could drive future research. The in-vitro and in-vivo experiments have demonstrated various favourable pharmacological properties of flavonoids. This review provides valuable information to conduct clinical studies, validating the safety aspects of flavonoids in the clinical domain.

Electronic redistribution through the interface of MnCo2O4-Ni3N nano-urchins prompts rapid In situ phase transformation for enhanced oxygen evolution reaction.

One of the most coveted objectives in the realm of energy conversion technologies is the development of highly efficient and economically viable electrocatalysts for the oxygen evolution reaction. The commercialization of such techniques has thus far been impeded by their slow response kinetics. One of the many ways to develop highly effective electrocatalysts is to judiciously choose a coupling interface that maximizes catalyst performance. In this study, the in situ electrochemical phase transformation of MnCo2O4-Ni3N into MnCo2O4-NiOOH is described. The catalyst has an exceptional overpotential of 224 mV to drive a current density of 10 mA cm-2. Strong interfacial contact is seen in the MnCo2O4-Ni3N catalyst, leading to a considerable electronic redistribution between the MnCo2O4 and Ni3N phases. This causes an increase in the valence state of Ni, which makes it an active site for the adsorption of *OH, O*, and *OOH (intermediates). This charge transfer facilitates the rapid phase transformation to form NiOOH from Ni3N. At a higher current density of 300 mA cm-2, the catalyst remained stable for a period of 140 h. DFT studies also revealed that the in situ-formed NiOOH on the MnCo2O4 surface results in superior OER kinetics compared to that of NiOOH alone.

Dipeptidyl peptidase 4 (DPP-4) inhibitors and the risk of lung cancer: current evidence and future directions.

INTRODUCTION: Recent evidence has linked long-term use of angiotensin converting enzyme (ACE) inhibitors with the risk of developing lung cancer by increasing levels of substance P (SP) and bradykinin in lung tissue. DPP-4 inhibitors, by virtue of their mechanism of action, may increase the level of SP and pose a similar risk of incident lung cancer. Concomitant use of DPP-4 inhibitors and ACE inhibitors may further exaggerate this plausible risk. AREA COVERED: Here we discuss both direct and indirect evidence involving mechanisms by which DPP-4 inhibitors may increase the risk of lung cancer in treated patients. We highlight that increased levels of SP with DPP-4 inhibitor monotherapy and raised levels of both SP and bradykinin with add-on ACE inhibitor therapy may further enhance this risk. EXPERT OPINION: DPP-4 inhibitors are prescribed in type-2 diabetes mellitus patients with or without cardiovascular disease. When used together, ACE inhibitors and DPP-4 inhibitors may act synergistically and further amplify the lung cancer risk. Consequently, physicians should consider this plausible association while prescribing them concomitantly especially in high-risk individuals. Well-planned research studies are required to assess the association of DPP-4 inhibitors with lung cancer and other adverse effects linked to increased levels of SP and bradykinin.

Finding the most cost-effective option from commonly used Dipeptidyl peptidase-4 inhibitors in India: a systematic study.

OBJECTIVE: To identify a preferred and cost-effective drug among Dipeptidyl peptidase-4 inhibitors (DPP4Is) for Indian patients with T2DM. METHODS: We performed a systematic literature search using standard databases for relevant literature. Original studies comparing the efficacy and/or safety of different DPP4Is were included. Two authors independently performed the literature search, screening, and collected relevant data from the selected studies. The costs of all brands of individual DPP4Is were noted and compared for lowest, highest, and average cost. Finally, we summarized the information with respect to Efficacy, safety, suitability, and cost to find the most cost-effective DPP4I. RESULTS: We found 13 eligible studies containing data on 15,720 subjects. These studies showed similar efficacy (or better) and safety with teneligliptin as compared to other DPP4Is. Teneligliptin also showed additional benefits other than the glycemic control. The average cost per tablet of teneligliptin 20 mg was markedly lower as compared to sitagliptin, vildagliptin, and other commonly used DPP4Is. Teneligliptin also outscored other commonly used DPP4Is in India in suitability and seems to have better patient compliance. CONCLUSIONS: Teneligliptin 20 mg could be considered as the preferred and most cost-effective agent among commonly used DPP4Is for the effective management of patients with T2DM in India.

Synergistic modulation in a triphasic Ni5P4-Ni2P@Ni3S2 system manifests remarkable overall water splitting.

The potential for water splitting electrocatalysts with high efficiency paves the way for a sustainable future in hydrogen energy. However, this task is challenging due to the sluggish kinetics of the oxygen evolution reaction (OER), which has a significant impact on the hydrogen evolution reaction (HER). Herein multi-heterointerface of Ni5P4-Ni2P@Ni3S2 was fabricated by a two-step synthesis procedure that consist the development of Ni5P4-Ni2P nanosheets over nickel foam followed by the electrodeposition of Ni3S2. The HR-TEM analysis shows that the Ni5P4-Ni2P@Ni3S2 nanosheets array provide numerous well-exposed diverse heterointerfaces. The electrochemical investigations conducted on the Ni5P4-Ni2P@Ni3S2 nanosheets for complete water splitting indicate that they possess an overpotential of 73 mV and 230 mV in HER and OER respectively, enabling them to generate a current density of 10 and 50 mA cm-2. The nanosheets also demonstrate Tafel slope values of 95 mV dec-1 and 83 mV dec-1 for HER and OER, respectively. The HER stability of the catalyst was conducted for 45 h using chronoamperometric technique under a current density of 20 mA cm-1, while the stability test for OER was carried out at current densities of 100 and 200 mA cm-1 for 100 h each. Furthermore, in the overall water splitting, the catalyst exhibits a cell voltage of 1.47 V@10 mA cm-2 and displayed a stability operation for 100 h at a current density of 150 mA cm-1.

Assessing the Incidence of New-onset Diabetes Mellitus with Statin Use: A Systematic Review of the Systematic Reviews and Meta-analyses.

Statin use has been linked with new-onset diabetes mellitus (NODM). In the present systematic review, we aimed to determine the incidence of NODM with statin use by assessing and summarizing the data generated by different systematic reviews and metaanalyses published on this topic. We conducted a systematic review of systematic reviews and meta-analyses using a pre-defined study protocol. Two authors independently performed a literature search using PubMed, Embase and the Cochrane Central Register of Controlled Trials (CENTRAL) for studies reporting data on statin use and NODM incidence and screened and extracted data for the outcomes of interest. The Assessing the Methodological Auality of Systematic Reviews 2 (AMSTAR 2) checklist was used to evaluate the quality of the included systematic reviews and meta-analyses. The initial search yielded 621 potential records, and 16 relevant systematic reviews and meta-analyses were included in the present systematic review. The included studies showed an increase in the risk of NODM with statin use. In particular, rosuvastatin and atorvastatin were associated with NODM in many systematic reviews or meta-analyses; however, pravastatin and pitavastatin were found to be associated with lower or no risk. We observed a positive trend of development of NODM with statin use became more evident with advancing years as more number of studies were added. Intensive doses of statins and use in older subjects were found to be important risk factors for NODM. Finally, the quality assessment revealed that the included systematic reviews and metaanalyses were of critically low or low quality. We concluded that statin use carries a risk of causing NODM. Statins should not be discouraged in anticipation of NODM. However, glycaemic monitoring should be encouraged with the on-going statin therapy. Furthermore, clinical studies addressing the use of statins and the incidence of NODM as their primary objective should be planned.

In-silico evaluation of bioactive compounds from tea as potential SARS-CoV-2 nonstructural protein 16 inhibitors.

BACKGROUND AND AIM: A novel coronavirus, called the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been found to cause COVID-19 in humans and some other mammals. The nonstructural protein 16 (NSP16) of SARS-CoV-2 plays a significant part in the replication of viruses and suppresses the ability of innate immune system to detect the virus. Therefore, inhibiting NSP16 can be a secure path towards identifying a potent medication against SARS-CoV-2. Tea (Camellia sinensis) polyphenols have been reported to exhibit potential treatment options against various viral diseases. METHODS: We conducted molecular docking and structural dynamics studies with a set of 65 Tea bioactive compounds to illustrate their ability to inhibit NSP16 of SARS-CoV-2. Moreover, post-simulations end state thermodynamic free energy calculations were estimated to strengthen our results. RESULTS AND CONCLUSION: Six bioactive tea molecules showed better docking scores than the standard molecule sinefungin. These results were further validated by MD simulations, where Theaflavin compound demonstrated lower binding free energy in comparison to the standard molecule sinefungin. The compound theaflavin could be considered as a novel lead compound for further evaluation by in-vitro and in-vivo studies.

Identification of selective cyclin-dependent kinase 2 inhibitor from the library of pyrrolone-fused benzosuberene compounds: an in silico exploration.

The over-expression of cyclin-dependent kinase 2 is related to multiple cancers, which has led them to be a widely researched topic for nearly two decades. The prime focus of the present research is to design new potent and specific inhibitors against CDK2 to suppress cancer cell proliferation. In this study, we have chosen Flavopiridol, SU9516, and CVT-313 as standard inhibitors to compare with in-house synthesized pyrrolone-fused benzosuberene (PBS) compounds. We scrutinized Ligand2 as a selective inhibitor of CDK2 without off-target binding (CDK1 and CDK9) based on ligand efficiency and binding affinity. Interpretation of dynamic simulations and binding free energy studies unveiled that Ligand2 has a stable and equivalent free energy to standard inhibitors. These outcomes led towards positioning a potential natural molecule as selective inhibitor for CDK2 with low side effects.

Correlation of serum amyloid A1 and interleukin-1beta in response to anti-tubercular therapy.

BACKGROUND: Host biomarkers are needed to monitor the response to anti-tubercular therapy (ATT) for ensuring effective therapy and preventing drug-resistant tuberculosis. We sought to find the correlation between the serum levels of SAA1 and IL-1beta in response to ATT in adult patients with pulmonary TB (PTB) or extra-pulmonary TB (EPTB). METHODS: Blood samples of 32 patients with PTB and 28 patients with EPTB were analyzed. The blood samples were collected at baseline, two months and six months following treatment initiation. SAA1 and IL-1beta levels were measured by enzyme linked immunosorbent assay (ELISA). RESULTS: In the PTB group, the mean levels of SAA1 decreased significantly (p <0.001) after the intensive phase (two months) and continuous phase (six months) of ATT in comparison with the baseline value. IL-1beta values also decreased significantly (p = 0.005) after the intensive phase (two months) compared with the baseline values. In the EPTB group, there was a significant reduction in the mean serum level of SAA1 (p <0.001) and IL-1beta (p = 0.001) after the intensive phase (two months) in comparison with the baseline value, whereas the reduction at six months was not significant. CONCLUSIONS: SAA1 and IL-1beta may be useful potential treatment-monitoring biomarkers, especially in the intensive phase of therapy for both PTB and EPTB.

Efficacy and safety of saroglitazar for the management of dyslipidemia: A systematic review and meta-analysis of interventional studies.

BACKGROUND AND OBJECTIVE: Saroglitazar is a newer antidiabetic agent approved to manage dyslipidemia. The objective is tevaluate the efficacy and safety profiles of saroglitazar in patients with dyslipidemia. METHODS: A systematic search was conducted using PubMed, Cochrane Library, Scopus, and Google Scholar from the inception until January 2022. Interventional studies comparing the anti-hyperlipidaemic effect and safety of saroglitazar with or without a control group(s) were included. The efficacy of saroglitazar was assessed concerning its effect on total cholesterol, low density lipoprotein (LDL) and high density lipoprotein (HDL)-cholesterol, triglycerides, fasting plasma glucose, and non-HDL cholesterol. The effects on serum creatinine levels, bodyweight reduction, alanine aminotransferase and aspartate aminotransferase were considered to be safety endpoint.The Cochrane risk of bias assessment tool was used to assess the methodological quality of the included studies. RESULTS: A total of six studies with 581 adults with a mean age ranging from 40.2 to 62.6 years were included in this study. A significant decrease in low-density lipoprotein cholesterol was observed with saroglitazar 4 mg therapy compared to saroglitazar 2 mg [standardized mean difference (SMD): -0.23 mg/dL, 95% CI: -0.47 to 0.00; p = 0.05; 2 studies], and control [SMD: -0.36 mg/dL, 95% CI -0.59 to -0.12; p = 0.0026; 3 studies]. Also, a significant decrease in the total cholesterol was observed with saroglitazar 4 mg therapy compared to saroglitazar 2 mg [SMD - 0.28 mg/dL, 95% CI: - 0.52 to -0.04; p < 0.01; 2 studies], and control [SMD - 0.49 mg/dL, 95% CI: - 0.72 to -0.26; p < 0.0001; 3 studies]. Saroglitazar was not associated with adverse effects such as increase in serum creatinine levels, alanine aminotransferase and aspartate aminotransferase and bodyweight reduction. CONCLUSION: Saroglitazar appeared to be an effective and safer therapeutic option for improving dyslipidemia in patients. However, comparative studies of saroglitazar with the other pharmacological agents are warranted.

Open label safety and efficacy pilot to study mitigation of equine recurrent uveitis through topical suppressor of cytokine signaling-1 mimetic peptide.

Equine recurrent uveitis (ERU) is a painful and debilitating autoimmune disease and represents the only spontaneous model of human recurrent uveitis (RU). Despite the efficacy of existing treatments, RU remains a leading cause of visual handicap in horses and humans. Cytokines, which utilize Janus kinase 2 (Jak2) for signaling, drive the inflammatory processes in ERU that promote blindness. Notably, suppressor of cytokine signaling 1 (SOCS1), which naturally limits the activation of Jak2 through binding interactions, is often deficient in autoimmune disease patients. Significantly, we previously showed that topical administration of a SOCS1 peptide mimic (SOCS1-KIR) mitigated induced rodent uveitis. In this pilot study, we test the potential to translate the therapeutic efficacy observed in experimental rodent uveitis to equine patient disease. Through bioinformatics and peptide binding assays we demonstrate putative binding of the SOCS1-KIR peptide to equine Jak2. We also show that topical, or intravitreal injection of SOCS1-KIR was well tolerated within the equine eye through physical and ophthalmic examinations. Finally, we show that topical SOCS1-KIR administration was associated with significant clinical ERU improvement. Together, these results provide a scientific rationale, and supporting experimental evidence for the therapeutic use of a SOCS1 mimetic peptide in RU.

Identification of potential plant bioactive as SARS-CoV-2 Spike protein and human ACE2 fusion inhibitors.

The Spike receptor binding domain (S-RBD) from SARS-CoV-2, a crucial protein for the entrance of the virus into target cells is known to cause infection by binding to a cell surface protein. Hence, reckoning therapeutics for the S-RBD of SARS-CoV-2 may address a significant way to target viral entry into the host cells. Herein, through in-silico approaches (Molecular docking, molecular dynamics (MD) simulations, and end-state thermodynamics), we aimed to screen natural molecules from different plants for their ability to inhibit S-RBD of SARS-CoV-2. We prioritized the best interacting molecules (Diacetylcurcumin and Dicaffeoylquinic acid) by analysis of protein-ligand interactions and subjected them for long-term MD simulations. We found that Dicaffeoylquinic acid interacted prominently with essential residues (Lys417, Gln493, Tyr489, Phe456, Tyr473, and Glu484) of S-RBD. These residues are involved in interactions between S-RBD and ACE2 and could inhibit the viral entry into the host cells. The in-silico analyses indicated that Dicaffeoylquinic acid and Diacetylcurcumin might have the potential to act as inhibitors of SARS-CoV-2 S-RBD. The present study warrants further in-vitro and in-vivo studies of Dicaffeoylquinic acid and Diacetylcurcumin for validation and acceptance of their inhibitory potential against S-RBD of SARS-CoV-2.

Identification of naturally originated molecules as γ-aminobutyric acid receptor antagonist.

γ-aminobutyric acid, being a principle neuromediator in humans controlling the inhibition signals, acts on the ligand-gated pentameric type A receptors to transmit their response. Any dysfunction of these receptors leads to neurological disorders and mental illness. Benzodiazepine has been used extensively for the treatment of these disorders, which shows its effect by reducing the threshold concentration of γ-aminobutyric acid required to activate the receptor. Being a central nervous system depressant, benzodiazepine is also a common substance of abuse along with other recreational drugs that show affinity towards the benzodiazepine binding site. Flumazenil is considered the first line of treatment for the overdose of these substances, which competes with them to bind with the receptor having a higher binding affinity towards the receptor. Like most of the synthetic drugs, Flumazenil also has some side-effects associated with it. Here we focus our work towards finding specific naturally originated antagonist of the benzodiazepine binding site to suggest an alternative for Flumazenil by performing various computational analysis like docking experiments followed by simulations and molecular mechanics poisson-boltzmann surface area analysis. Molecular docking experiments filtered out four ligand molecules specific for the benzodiazepine binding site, namely, ligand-1,7,9 and 17. Further, molecular dynamics simulations showed ligand-17 to have stable conformation in the binding site as well as a lower binding free energy as compared to Flumazenil. Due to its natural origin, ligand-17 is supposed to have lower side effects; therefore, its backbone can be further explored to develop specific antagonists of benzodiazepines. Communicated by Ramaswamy H. Sarma.

Bioactive Molecules of Tea as Potential Inhibitors for RNA-Dependent RNA Polymerase of SARS-CoV-2.

The coronavirus disease (COVID-19), a worldwide pandemic, is caused by the severe acute respiratory syndrome-corona virus-2 (SARS-CoV-2). At this moment in time, there are no specific therapeutics available to combat COVID-19. Drug repurposing and identification of naturally available bioactive molecules to target SARS-CoV-2 are among the key strategies to tackle the notorious virus. The enzyme RNA-dependent RNA polymerase (RdRp) performs a pivotal role in replicating the virus. RdRp is a prime target for Remdesivir and other nucleotides analog-based antiviral drugs. In this study, we showed three bioactive molecules from tea (epicatechin-3,5-di-O-gallate, epigallocatechin-3,5-di-O-gallate, and epigallocatechin-3,4-di-O-gallate) that showed better interaction with critical residues present at the catalytic center and the NTP entry channel of RdRp than antiviral drugs Remdesivir and Favipiravir. Our computational approach to identify these molecules included molecular docking studies, followed by robust molecular dynamics simulations. All the three molecules are readily available in tea and could be made accessible along with other medications to treat COVID-19 patients. However, these results require validation by further in vitro and in vivo studies.