Rutin from Begonia roxburghii modulates iNOS and Sep A activity in treatment of Shigella flexneri induced diarrhoea in rats: An in vitro, in vivo and computational analysis.

In developing countries, diarrhoea is a major issue of concern, where consistent use of antibiotics has resulted in several side effects along with development of resistance among pathogens against these antibiotics. Since natural products are becoming the treatment of choice, therefore present investigation involves mechanistic evaluation of antidiarrhoeal potential of Begonia roxburghii and its marker rutin against Shigella flexneri (SF) induced diarrhoea in rats following in vitro, in vivo and in silico protocols. The roots of the plant are used as vegetable in the North East India and are also used traditionally in treating diarrhoea. Phytochemically standardized ethanolic extract of B. roxburghii (EBR) roots and its marker rutin were first subjected to in vitro antibacterial evaluation against SF. Diarrhoea was induced in rats using suspension of SF and various diarrhoeagenic parameters were examined after first, third and fifth day of treatment at 100, 200 and 300 mg/kg, p.o. with EBR and 50 mg/kg, p.o. with rutin respectively. Additionally, density of SF in stools, stool water content, haematological and biochemical parameters, cytokine profiling, ion concentration, histopathology and Na+/K+-ATPase activity were also performed. Molecular docking and dynamics simulation studies of ligand rutin was studied against secreted extracellular protein A (Sep A, PDB: 5J44) from SF and Inducible nitric oxide synthase (iNOS, PDB: 1DD7) followed by network pharmacology. EBR and rutin demonstrated a potent antibacterial activity against SF and also showed significant recovery from diarrhoea (EBR: 81.29 ± 0.91% and rutin: 75.27 ± 0.89%) in rats after five days of treatment. EBR and rutin also showed significant decline in SF density in stools, decreased cytokine expression, potential antioxidant activity, cellular proliferative nature and recovered ion loss due to enhanced Na+/K+-ATPase activity, which was also supported by histopathology. Rutin showed a very high docking score of -11.61 and -9.98 kcal/mol against iNOS and Sep A respectively and their stable complex was also confirmed through dynamics, while network pharmacology suggested that, rutin is quite capable of modulating the pathways of iNOS and Sep A. Thus, we may presume that rutin played a key role in the observed antidiarrhoeal activity of B. roxburghii against SF induced diarrhoea.

Analysing the impact of eriosematin E from Eriosema chinense Vogel. against different diarrhoeagenic pathovars of Escherichia coli using in silico and in vitro approach.

Since diarrhoea is reportedly the third largest cause of fatality among kids, therefore it is considered to be one of the major areas of concerns among developing nations. The main causative agents of diarrhoea include Escherichia coli, Vibrio cholera, and Shigella spp where E. coli shares the maximum contribution. The roots of the plant Eriosema chinense Vogel. (Fabaceae) are traditionally used by the native tribes of Meghalaya, India to treat diarrhoea. From previous reports, the plant and its marker eriosematin E have been reported to have antidiarrhoeal potential against pathogenic and nonpathogenic diarrhoea. Therefore, the objective of the current investigation was to use in silico studies to determine the efficacy of eriosematin E against different diarrhoeagenic strains of E. coli. Six different pathovars of E. coli i.e. enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), enterohaemorrhagic E. coli (EHEC), enteroaggregative E. coli (EAEC), uropathogenic E. coli (UPEC) and enteroinvasive E. coli (EIEC) were subjected to docking simulation studies utilizing Glide module of Schrodinger Maestro 2018-1 MM Share Version. Based on the obtained binding energy and balance between H-bonding, hydrophobic, and salt bridge interactions eriosematin E was found to be most effective against EPEC followed by EAEC and ETEC, while UPEC and EHEC were moderately affected. The molecular dynamics studies suggested a higher affinity of eriosematin E towards heat-labile enterotoxin b-pentamer from ETEC. The in vitro antibacterial studies against the universal strain S. aureus 12981 and E. coli 10418 revealed the effectiveness of eriosematin E showing MIC values of ≥256 µg/mL.Communicated by Ramaswamy H. Sarma.

An in-silico evaluation of different Saikosaponins for their potency against SARS-CoV-2 using NSP15 and fusion spike glycoprotein as targets.

The Public Health Emergency of International Concern declared the widespread outbreak of SARS-CoV-2 as a global pandemic emergency, which has resulted in 1,773,086 confirmed cases including 111,652 human deaths, as on 13 April 2020, as reported to World Health Organization. As of now, there are no vaccines or antiviral drugs declared to be officially useful against the infection. Saikosaponin is a group of oleanane derivatives reported in Chinese medicinal plants and are described for their anti-viral, anti-tumor, anti-inflammatory, anticonvulsant, antinephritis and hepatoprotective activities. They have also been known to have anti-coronaviral property by interfering the early stage of viral replication including absorption and penetration of the virus. Thus, the present study was undertaken to screen and evaluate the potency of different Saikosaponins against different sets of SARS-CoV-2 binding protein via computational molecular docking simulations. Docking was carried out on a Glide module of Schrodinger Maestro 2018-1 MM Share Version on NSP15 (PDB ID: 6W01) and Prefusion 2019-nCoV spike glycoprotein (PDB ID: 6VSB) from SARS-CoV-2. From the binding energy and interaction studies, the Saikosaponins U and V showed the best affinity towards both the proteins suggesting them to be future research molecule as they mark the desire interaction with NSP15, which is responsible for replication of RNA and also with 2019-nCoV spike glycoprotein which manage the connection with ACE2. [Formula: see text] Communicated by Ramaswamy H. Sarma.

Sars-cov-2 host entry and replication inhibitors from Indian ginseng: an in-silico approach.

COVID-19 has ravaged the world and is the greatest of pandemics in modern human history, in the absence of treatment or vaccine, the mortality and morbidity rates are very high. The present investigation identifies potential leads from the plant Withania somnifera (Indian ginseng), a well-known antiviral, immunomodulatory, anti-inflammatory and a potent antioxidant plant, using molecular docking and dynamics studies. Two different protein targets of SARS-CoV-2 namely NSP15 endoribonuclease and receptor binding domain of prefusion spike protein from SARS-CoV-2 were targeted. Molecular docking studies suggested Withanoside X and Quercetin glucoside from W. somnifera have favorable interactions at the binding site of selected proteins, that is, 6W01 and 6M0J. The top-ranked phytochemicals from docking studies, subjected to 100 ns molecular dynamics (MD) suggested Withanoside X with the highest binding free energy (ΔGbind = -89.42 kcal/mol) as the most promising inhibitor. During MD studies, the molecule optimizes its conformation for better fitting with the receptor active site justifying the high binding affinity. Based on proven therapeutic, that is, immunomodulatory, antioxidant and anti-inflammatory roles and plausible potential against n-CoV-2 proteins, Indian ginseng could be one of the alternatives as an antiviral agent in the treatment of COVID 19. Communicated by Ramaswamy H. Sarma.

Identifying the mechanism of eriosematin E from Eriosema chinense Vogel. for its antidiarrhoeal potential against Shigella flexneri-induced diarrhoea using in vitro, in vivo and in silico models.

The main objective of the present investigation was to mechanistically evaluate the potency of the root extract (EEC), its bioactive chloroform fraction (CEC) and eriosematin E (ECM) isolated from Eriosema chinense against Shigella flexneri-induced sub-chronic model of infectious diarrhoea using in vitro, in vivo, and in silico methods. The in vitro antibacterial activity against pathogenic strain of S. flexneri demonstrated maximum effect of ECM followed by CEC and EEC in inhibiting growth of bacteria. Further, for in vivo evaluation, was carried out by inducing diarrhoea to the rats by administering oral suspension of S. flexneri to the animals, which was followed by treatment for a period of 6 days. EEC at 200, CEC at 100 and ECM at 10 mg/kg, p.o. showed promising effect, where EEC and ECM were found to be more effective showing maximum % protection on 6th day. Results also demonstrated a significant restoration of altered antioxidants, pro-inflammatory cytokines (IL-1ß and TNF-α) expression, electrolyte balance, Na+/K+-ATPase activity and was also supported by histopathological examinations. Molecular docking study revealed that, eriosematin E inactivated the protease activity of SepA, a protein secreted by Shigella, which is responsible for disruption of epithelial barrier integrity. Thus, the overall observation confirmed the role of eriosematin E from E. chinense in treatment of Shigella flexneri-induced infectious diarrhoea.

Effect of ethanolic extract of Solanum virginianum Linn. on neuropathic pain using chronic constriction injury rat model and molecular docking studies.

The present research work was designed to examine the neuroprotective effect of ethanolic extract of Solanum virginianum Linn. (SV) in chronic construction injury (CCI) of sciatic nerve-induced neuropathic pain in rats. The extract was initially standardized by high-performance thin-layer chromatography using solasodine as a biomarker and was then subjected to assess the degree of mechanical allodynia, thermal allodynia, mechanical hyperalgesia, thermal hyperalgesia and biochemical evaluations. Administration of SV (100 and 200 mg/kg; p.o.) and pregabalin (10 mg/kg; p.o.) as a reference standard significantly debilitated hyperalgesia and allodynia and notably restored the altered antioxidant level and pro-inflammatory cytokine (IL-1ß and TNF-α) expression in a dose-dependent manner. Further, to appraise the mechanistic approach of solasodine, docking simulation studies were done on the 3D structure of the voltage-gated N-type calcium channel (Cav 2.2), R-type calcium channel (Cav 2.3) and sodium channel (Nav 1.7), and the results revealed that solasodine properly positioned into Phe 19, Leu 32, Met 51 and Met 71 (FLMM pocket) of Cav 2.2 and Cav 2.3 and being a competitor of Ca2+/N-lobe it may inactivate these calcium channels but did not bind into the desired binding pocket of Nav 1.7. Thus, the study confirmed the role of solasodine as a major biomarker for the observed neuroprotective nature of Solanum virginianum.

The antidiarrhoeal evaluation of Psidium guajava L. against enteropathogenic Escherichia coli induced infectious diarrhoea.

ETHNOPHARMACOLOGICAL RELEVANCE: The plant Psidium guajava L. (Myrtaceae), commonly used as an edible fruit is traditionally used worldwide in treatment of various gastrointestinal problems including diarrhoea. The leaves of the plant have also been evaluated for antidiarrhoeal activity in various chemical induced diarrhoea models. OBJECTIVE: The main objective of the present study was to evaluate the potency of P. guajava leaves and its major biomarker quercetin against enteropathogenic Escherichia coli (EPEC) induced infectious diarrhoea using preclinical and computational model. MATERIAL AND METHODS: P. guajava alcoholic leaf extract (PGE) was initially standardized using HPLC taking quercetin as a biomarker and was then subjected to antidiarrhoeal evaluation on rats in an EPEC induced diarrhoea rat model. The study included assessment of various behavioral parameters, initially for 6 h and then for up to 24 h of induction which was followed by estimation of stool water content, density of EPEC in stools and blood parameters evaluation. The colonic and small intestinal tissues of the treated animals were subjected to various biochemical estimations, in vivo antioxidant evaluation, estimation of ion concentration, Na+/K+-ATPase activity, assessment of pro-inflammatory cytokines and histopathological studies. Further, the major biomarker off PGE, quercetin was subjected to molecular docking studies with Na+/K+-ATPase and EPEC. RESULTS: The results demonstrated a significant antidiarrhoeal activity of quercetin (50 mg/kg), PGE at 200 and 400 mg/kg, p.o., where quercetin and PFGE at 200 mg/kg, p.o. were found to be more prominent, as confirmed through higher % protection, water content of stools and density of EPEC in stools. PGE and its biomarker quercetin also significantly recovered the WBC, Hb, platelets loss and also revealed a significant restoration of altered antioxidants level, pro-inflammatory cytokines (IL-1ß and TNF-α) expression and had positive influence on Na+/K+-ATPase activity. The docking studies of quercetin with Na+/K+-ATPase showed favourable interactions and residues Glu 327, Ser 775, Asn 776, Glu 779 and Asp 804 of Na+/K+-ATPase were adequately similar to quercetin for donating ligands for binding, while quercetin was also found to terminate the linkage between mammalian cells and EPEC thus, preventing further infection from EPEC. CONCLUSION: Inhibition in intestinal secretion, reduced nitric oxide production and inflammatory expression along with reactivation of Na+/K-ATPase activity could be attributed to the observed antidiarrhoeal potential of PGE against infectious diarrhoea, where quercetin was confirmed to be the main contributing factor.

Quercetin a major biomarker of Psidium guajava L. inhibits SepA protease activity of Shigella flexneri in treatment of infectious diarrhoea.

The leaves of the plant Psidium guajava L. (Myrtaceae) has been traditionally used in treatment of various gastrointestinal disorders including diarrhoea and have also been reported for its potent antidiarrhoeal activity on various chemical induced diarrhoea models. The objective of our present study was to evaluate the potency of the leaf extract of the plant Psidium guajava (PGE) along with its major biomarker quercetin against Shigella flexneri-induced sub chronic model of infectious diarrhoea. PGE at 100, 200 and 400 mg/kg, p.o. and quercetin at 50 mg/kg, p.o. were administered to Shigella flexneri-induced diarrhoeal rats for five days and various behavioural parameters were evaluated on 1st, 3rd and 5th day of treatment. This was followed by assessment of stool water content, density of Shigella flexneri in stools and blood parameters examination. After treatment, colon and small intestine of rats was dissected and subjected to biochemical estimations, cytokine profiling, antioxidant evaluations, ion concentration determination, Na+/K+-ATPase activity and histopathology. Molecular docking studies on crystal structure of Secreted Extracellular Protein A (SepA) from Shigella flexneri with biomarker quercetin was also performed. PGE at 200 mg/kg followed by quercetin depicted maximum antidiarrhoeal potential, which was confirmed through diarrhoea score and % protection, while PGE at 400 mg/kg showed similar effect to PGE 200 mg/kg thus, the later may have ceiling effect. PGE and quercetin also significantly reduced the density of Shigella flexneri in stools, water content of stools and restored the alterations observed in blood parameters, antioxidant status and pro-inflammatory cytokines (IL-6 and TNF-α) expression. These parameters contributed in normalization of electrolyte balance, reactivation of Na+/K+-ATPase activity and repairing of epithelial tissue damage, confirmed through histopathology. Docking simulation studies revealed the role of quercetin in inactivating the protease activity of SepA, a protein secreted by Shigella, which disrupts epithelial barrier integrity during infection and also manages its signal production. Thus, the overall results confirmed the role of quercetin as a major biomarker for the observed antidiarrhoeal potential of P. guajava against Shigella flexneri induced infectious diarrhoea.