In-silico evaluation of natural alkaloids against the main protease and spike glycoprotein as potential therapeutic agents for SARS-CoV-2

Severe Acute Respiratory Syndrome Corona Virus (SARS-CoV-2) is the causative agent of COVID-19 pandemic, which has resulted in global fatalities since late December 2019. Alkaloids play a significant role in drug design for various antiviral diseases, which makes them viable candidates for treating COVID-19. To identify potential antiviral agents, 102 known alkaloids were subjected to docking studies against the two key targets of SARS-CoV-2, namely the spike glycoprotein and main protease. The spike glycoprotein is vital for mediating viral entry into host cells, and main protease plays a crucial role in viral replication; therefore, they serve as compelling targets for therapeutic intervention in combating the disease. From the selection of alkaloids, the top 6 dual inhibitory compounds, namely liensinine, neferine, isoliensinine, fangchinoline, emetine, and acrimarine F, emerged as lead compounds with favorable docked scores. Interestingly, most of them shared the bisbenzylisoquinoline alkaloid framework and belong to Nelumbo nucifera, commonly known as the lotus plant. Docking analysis was conducted by considering the key active site residues of the selected proteins. The stability of the top three ligands with the receptor proteins was further validated through dynamic simulation analysis. The leads underwent ADMET profiling, bioactivity score analysis, and evaluation of drug-likeness and physicochemical properties. Neferine demonstrated a particularly strong affinity for binding, with a docking score of -7.5025 kcal/mol for main protease and -10.0245 kcal/mol for spike glycoprotein, and therefore a strong interaction with both target proteins. Of the lead alkaloids, emetine and fangchinoline demonstrated the lowest toxicity and high LD50 values. These top alkaloids, may support the body's defense and reduce the symptoms by their numerous biological potentials, even though some properties naturally point to their direct antiviral nature. These findings demonstrate the promising anti-COVID-19 properties of the six selected alkaloids, making them potential candidates for drug design. This study will be beneficial in effective drug discovery and design against COVID-19 with negligible side effects.

Discovering common pathogenetic processes between COVID-19 and sepsis by bioinformatics and system biology approach

Corona Virus Disease 2019 (COVID-19), an acute respiratory infectious disease caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has spread rapidly worldwide, resulting in a pandemic with a high mortality rate. In clinical practice, we have noted that many critically ill or critically ill patients with COVID-19 present with typical sepsis-related clinical manifestations, including multiple organ dysfunction syndrome, coagulopathy, and septic shock. In addition, it has been demonstrated that severe COVID-19 has some pathological similarities with sepsis, such as cytokine storm, hypercoagulable state after blood balance is disrupted and neutrophil dysfunction. Considering the parallels between COVID-19 and non-SARS-CoV-2 induced sepsis (hereafter referred to as sepsis), the aim of this study was to analyze the underlying molecular mechanisms between these two diseases by bioinformatics and a systems biology approach, providing new insights into the pathogenesis of COVID-19 and the development of new treatments. Specifically, the gene expression profiles of COVID-19 and sepsis patients were obtained from the Gene Expression Omnibus (GEO) database and compared to extract common differentially expressed genes (DEGs). Subsequently, common DEGs were used to investigate the genetic links between COVID-19 and sepsis. Based on enrichment analysis of common DEGs, many pathways closely related to inflammatory response were observed, such as Cytokine-cytokine receptor interaction pathway and NF-kappa B signaling pathway. In addition, protein-protein interaction networks and gene regulatory networks of common DEGs were constructed, and the analysis results showed that ITGAM may be a potential key biomarker base on regulatory analysis. Furthermore, a disease diagnostic model and risk prediction nomogram for COVID-19 were constructed using machine learning methods. Finally, potential therapeutic agents, including progesterone and emetine, were screened through drug-protein interaction networks and molecular docking simulations. We hope to provide new strategies for future research and treatment related to COVID-19 by elucidating the pathogenesis and genetic mechanisms between COVID-19 and sepsis.

Novel Synergistic Anti-Enteroviral Drug Combinations

Background: Enterovirus infections affect people around the world, causing a range of illnesses, from mild fevers to severe, potentially fatal conditions. There are no approved treatments for enterovirus infections. Methods: We have tested our library of broad-spectrum antiviral agents (BSAs) against echovirus 1 (EV1) in human adenocarcinoma alveolar basal epithelial A549 cells. We also tested combinations of the most active compounds against EV1 in A549 and human immortalized retinal pigment epithelium RPE cells. Results: We confirmed anti-enteroviral activities of pleconaril, rupintrivir, cycloheximide, vemurafenib, remdesivir, emetine, and anisomycin and identified novel synergistic rupintrivir–vemurafenib, vemurafenib–pleconaril and rupintrivir–pleconaril combinations against EV1 infection. Conclusions: Because rupintrivir, vemurafenib, and pleconaril require lower concentrations to inhibit enterovirus replication in vitro when combined, their cocktails may have fewer side effects in vivo and, therefore, should be further explored in preclinical and clinical trials against EV1 and other enterovirus infections.

The expectorant action of cephaeline, emetine and 2-dehydroemetine

Cephaeline, emetine and 2-dehydroemetine were administered, as the dihydrochlorides, in doses from 0.1 to 81 mg/kg body weight, orally and subcutaneously to 135 rabbits and 92 cats arranged for the collection of respiratory tract fluid. To the extent that comparisons were made, the effects of the three alkaloids were identical. The volume output of respiratory tract fluid was increasingly augmented by doses of from 0.1 to 1.0 mg/kg. No further increase followed administration of higher doses up to the highest non-lethal dose. Doses of from 9.0 to 81 mg/kg were increasingly lethal and increasingly depressed the output of respiratory tract fluid, probably through their cardiotoxic action. Lethal doses were similar for all three alkaloids and by both routes of administration. It is concluded that the expectorant action of ipecacuanha is due in whole or in major part to its content of emetine and cephaeline. The expectorant action of synthetic 2-dehydroemetine is essentially similar to that of emetine and cephaeline.

Studies on two new Cephaline gregarines from the intestine of Indian insects, Gryllodes sigillatus and Liogryllus bimaculatus

A description is given of two new Cephaline gregarines from Indian crickets collected at Lucknow and Jalaun, United Provinces.

One of these, Stenophora gryllodes-sigillatae sp.nov., from the gut of Gryllodes sigillatus, has solitary slender trophozoites up to 194μ long. Its epimerite is rounded in young forms and absent or represented by its remnant in adults. The nucleus has two chromosomes. Cysts are rounded, invested in a very thin membrane and without sporoducts.

The second, Bulbocephalus indicus sp.nov., from the gut of Liogryllus bimaculatus, is characterized by solitary elongated sporadins; the neck is short and a bulbous epimerite is always present. The body, measuring up to 175μ in length and up to 30μ in breadth, presents a striated appearance. Cysts are oval, covered by a very thin membrane, and have no sporoducts.

The author is very grateful to Dr S. M. Das, under whose able guidance this work was carried out. His thanks are also due to the Department of Zoology, University of Lucknow, for providing the laboratory facilities.

Experimental hepatic amoebiasis and its application to chemotherapeutic studies

Induction of hepatic amoebiasis with two strains of Entamoeba histolytica has been attempted by direct inoculation of trophozoites into the livers of rats, hamsters, and guinea-pigs, and by intravenous injection into guinea-pigs. A high incidence of amoebic abscesses was obtained in hamsters. Rats and guinea-pigs were relatively less susceptible. The two strains of Entamoeba histolytica differed in virulence. Serial liver passage increased their virulence for the hamster liver, and also increased invasiveness to the rat caecum. The chemotherapeutic effects of chloroquine, emetine, and some anilides were determined. The procedure finally adopted was based on mean survival times of treated and untreated animals. Chloroquine and emetine were effective under conditions which greatly favoured the drugs, but the anilides showed little effect.

TOXICITY AND TISSUE DISTRIBUTION STUDIES ON THE HYDROCHLORIDE, BISMUTH IODIDE COMPLEX AND A RESINATE OF EMETINE

The hydrochloride, the bismuth iodide complex and a resinate of emetine have been compared on mice, cats and dogs for toxicity, on cats for emetic activity and on rats for distribution of emetine in the tissues. Emetine hydrochloride, injected sub-cutaneously, was as toxic as emetine hydrochloride or emetine bismuth iodide administered orally, but only one-sixth as emetic. Given orally emetine resinate was considerably less toxic and emetic than the other preparations. The patterns of emetine distribution in the tissues of rats were similar for all the preparations, but the tissue concentrations were much lower with emetine resinate. In infected rats the resinate was as amoebicidal as the hydrochloride or the bismuth iodide complex. It is suggested that emetine resinate might be better than emetine bismuth iodide for the treatment of intestinal amoebiasis.

Involvement of protein phosphatases 1 and 2A in the control of M phase-promoting factor activity in starfish

Specific inhibition of types 1 and 2A protein phosphatases by microinjection of okadaic acid (OA) into starfish oocytes induced germinal vesicle breakdown and activation of M phase-promoting factor (MPF) and histone H1 kinase. The effects were evident in immature oocytes arrested at first meiotic prophase as well as in fully mature oocytes arrested at the pronucleus stage. In addition, MPF and histone H1 kinase were stabilized for several hours and protected from inactivation by inhibition of type 1 protein phosphatases with either OA or specific anti-phosphatase antibodies. Microinjection of okadaic acid was associated with unusual changes of the microtubule network, including the disappearance of spindles and extension of the cytoplasmic array of microtubules. MPF activation after OA injection was associated with dephosphorylation of phosphothreonine and phosphoserine residues in cdc2, showing that neither type 1 nor 2A protein phosphatases catalyzes these dephosphorylations. The effects of OA on MPF activation and inactivation appeared to involve the cyclin subunit. OA did not induce MPF activation in the absence of protein synthesis and it prevented degradation of cyclin. Therefore protein phosphatases types 1 and 2A appear to be involved in activation and inactivation of MPF involving mechanisms that operate after cyclin synthesis and before its degradation.

Protective effect of metoprolol on emetine induced T wave changes in animals

We studied the protective effect of metoprolol on emetine induced T wave changes in rabbits. None of the rabbits who were beta-blocked before administration of emetine develop the T wave changes observed consistently in the control group. These observations support our clinical impression that emetine-induced T wave changes are produced because of stimulation of peripheral sympathetic nervous system and can be effectively prevented by prior and concomitant beta-blockade.

[History and importance of electrically excitable artificial membranes]

Solubility of narcotics in lipids has promoted the quest for non-aqueous and lipidic models of cell membranes. Artificial phosphatidic bilayers have been proposed. They display ionic conductance and excitability only if they are in contact with cyclic ion-carrier or specific substances, such as the protein fraction EIM. However many lipidic substances form non-bilayer membranes ion-conducting and excitable, without any specific additive. Only a small amount of free fatty acid is necessary. This is the condition for penetration through cation exchange. Coloured cations and cationic drugs undergo large exchange. Cu++, Hg++, emetine ++ cations have very high exchange coefficients which can be experimentally measured and which explain their respective antifungal, antibacterial and antiamoebian actions. The possible processes of membrane excitation are discussed. First the classical pores, specific of K+ and Na+ transfers and their "gating" mechanisms, because cell membranes are bi-ionic systems. Artificial membranes, are mono-ionic systems. But recent work shows that the axon membrane can be transformed into a monoionic system with Co++ as the only cations inside and outside the axon. Suggestions for the excitation processes are proposed. a) The assumption of a single energy barrier corresponding to minor conformational changes of structure. b) The membrane may be thixotropic. An outside cation penetrating the membrane would leave behind itself a wake of fluidity into which the next cations could penetrate if they follow each other closely. If they progress widely apart (under a small field), the ionic current would soon stop as the structure solidifies. c) The most promising suggestion is that anionic fixed charges in the membranes and cations form electrostatically bound ion-pairs. Dissociation of such pairs, that is conductance, augments markedly when dielectric constant increases. This process could be produced by water carried by incoming cations, that is by electro osmosis. This is exactly what occurs in Teorell's membrane oscillator in which a model membrane of fritted glass displays, under a weak current, oscillations of water flux and of potentials. The calculations pertaining to this model can be generalised if the electroosmotic water flux is assumed in increase the dielectric constant of the lipidic membrane. Thus the notion of an electroosmotic increase upon the dielectric constant of the membrane offers an alternative to the pore theory. Besides other phenomena show the role of low dielectric constants. The conductance of lipids containing coloured cations increase when subjected to illumination. The radiant energy absorbed then surpasses the association energy of ion pairs.

In vitro evidence for ipecac inactivation by activated charcoal

The in vitro adsorption of the alkaloid emetine, a primary constituent of ipecac, on activated charcoal was studied. The results support the supposition that syrup of ipecac should not be given to counteract poisonings if activated charcoal is also to be administered.

Electrocardiogram after Chloroquine and Emetine

Electrocardiographic abnormalities have been studied after administration of chloroquine in 25 patients, of emetine in 28 patients, and of emetine and chloroquine in 28 patients.

Abnormalities after chloroquine were less in severity and of shorter duration than after emetine. They were more severe, became maximum later after cessation of emetine therapy, and were much longer in duration after emetine and chloroquine than after emetine. These differences are attributed to combined effects of the two drugs.

Serum potassium levels showed some decrease after antiamebic therapy, the decrease being more after emetine than after chloroquine.

A case is reported in which severe abnormalities and muscular paralysis occurring after emetine and chloroquine were rapidly reversed by oral potassium administration.

Administration of potassium simultaneously with emetine and chloroquine often prevented or delayed the appearance or decreased the severity of abnormalities. Subsequent potassium administration usually reversed the abnormalities except in cases in which they were present before emetine therapy. It is concluded that the abnormalities are functional in nature and not due to organic myocardial damage.

It is suggested that some disturbance of potassium metabolism in the myocardium and skeletal muscles may be the cause of electrocardiographic abnormalities and emetine neuritis, respectively.

BEHAVIOUR THERAPY FOR TRANSVESTISM. A COMPARISON OF PHARMACOLOGICAL AND ELECTRICAL AVERSION TECHNIQUES

Transvestism is characterized by a repetitive morbid predilection to dress in the attire of the opposite sex. It is distinguishable from fetishism on the one hand and trans-sexualism on the other.