Identification of novel inhibitor phytoconstituents for Influenza A H3N2: an in silico approach.

Influenza A virus subtype H3N2 is a highly infectious respiratory virus that is responsible for global seasonal flu epidemics. The current study was designed to investigate the antiviral activity of 150 phytocompounds of North Western Himalayas medicinal plants by molecular docking. Two target proteins of hemagglutinin of influenza virus A (PDB ID 4WE8) and Influenza virus H3N2 nucleoprotein - R416A mutant (PDB ID 7NT8) are selected for this study. Molecular docking was done by AutoDock vina tool, toxicity and drug-likeness prediction was done by protox II and Moleinspiration. MD simulation of best protein-ligand complexes was done by using Gromacs, version 2021.5. Molecular docking and toxicity data revealed that clicoemodin and rumexocide showed the best binding with both target proteins 4WEB & 7NT8. Clicoemodin showed the -7.5 KJ/mol binding energy with 4WE8 and 7NT8. Similarly, rumexoside showed the -7.6 KJ/mol binding energy with 4WE8 and -7.6 KJ/mol with 7NT8. Furthermore, Molecular dynamic simulation and MMPBSA binding free energy validated the stability of protein-ligand complexes. The current study suggested that clicoemodin and rumexocide are the promising inhibitors of H3N2 proteins hemagglutinin of influenza virus A and Influenza virus H3N2 nucleoprotein - R416A mutant, though there is further in vitro and in vivo validation is required.Communicated by Ramaswamy H. Sarma.

Antimicrobial potential of phytocompounds of Acorus calamus: in silico approach.

Medicinal plants are used from prehistoric time to cure various life-threatening bacterial diseases. Acorus calamus is an important medicinal plant widely used to cure gastrointestinal, respiratory, kidney and liver disorders. The objective of the current research was to investigate the interaction of major phytoconstituents of Acorus calamus with bacterial (6VJE) and fungal (1EA1) protein targets. Protein-ligand interactions were estimated using the AutoDock software, drug likeness was predicted by using the molinspiration server and toxicity was predicted with the swissADME and protox II servers. MD simulation of phytocompounds with the best profiles was done on the GROMACS software for 100 ns. Molecular docking results showed among all the selected major phytoconstituents, that ß-cadinene showed best binding interaction in complex with bacterial (6VJE) and fungal (1EA1) protein targets with binding energy -7.66 ± 0.1 and -7.73 ± 0.15 kcal mol-1, respectively. Drug likeness and toxicity predictions showed that ß-cadinene follows all rules of drug likeness and toxicity. MD simulation study revealed that ß-cadinene fit in binding pocket of bacterial and fungal targets and found to be stable throughout the duration of the simulation. Based on the observations from this in-silico study it is being proposed that ß-cadinene, a major phytocompound of Acorus calamus, can be considered for the treatment of bacterial and fungal infections since the study shows that it might be one of the compounds that contributes majorly to the plant's biological activity. This study needs in vitro and in vivo validation.Communicated by Ramaswamy H. Sarma.

A comprehensive review on traditional applications, phytochemistry, pharmacology, and toxicology of Thymus serpyllum.

Thymus serpyllum L. from the Lamiaceae family is an underexplored perennial medicinal shrub with traditional usage in treating respiratory and gastrointestinal issues in the upper foothills of India. This review aims to provide a comprehensive assessment of current knowledge concerning the traditional uses, phytochemistry, and pharmacology of T. serpyllum. The primary objective is to collect updated information on this plant and encourage further in vivo and in vitro research to validate local claims. Notably, the essential oil derived from T. serpyllum has gained significant attention as a plant-derived product due to its diverse pharmacological properties, including antioxidative, antimicrobial, anti-inflammatory, and anticancer activities. Ethnomedicinal research revealed a vast scope of T. serpyllum in developing new drugs to address numerous health sector challenges. While T. serpyllum has been used widely, pharmacological studies are not enough. Most studies are either in vivo or in vitro. More studies are required to assess these medicinal claims through well-planned pharmacological experiments. This review will provide the groundwork for future research. While T. serpyllum has been put to considerable conventional use, pharmacological studies are insufficient; most studies are either in vivo or in vitro. More compound isolation, comprehensive pharmacological analysis, and exploration of food applications are vital areas to investigate.

Antibacterial Potential of Bacopa monnieri (L.) Wettst. and Its Bioactive Molecules against Uropathogens-An In Silico Study to Identify Potential Lead Molecule(s) for the Development of New Drugs to Treat Urinary Tract Infections.

Urinary tract infections (UTIs) are becoming more common, requiring extensive protection from antimicrobials. The global expansion of multi-drug resistance uropathogens in the past decade emphasizes the necessity of newer antibiotic treatments and prevention strategies for UTIs. Medicinal plants have wide therapeutic applications in both the prevention and management of many ailments. Bacopa monnieri is a medicinal plant that is found in the warmer and wetlands regions of the world. It has been used in Ayurvedic systems for centuries. The present study aimed to investigate the antibacterial potential of the extract of B. monnieri leaves and its bioactive molecules against UTIs that are caused by Klebsiella pneumoniae and Proteus mirabilis. This in vitro experimental study was conducted by an agar well diffusion method to evaluate the antimicrobial effect of 80% methanol, 96% ethanol, and aqueous extracts of B. monnieri leaves on uropathogens. Then, further screening of their phytochemicals was carried out using standard methods. To validate the bioactive molecules and the microbe interactions, AutoDock Vina software was used for molecular docking with the Klebsiella pneumoniae fosfomycin resistance protein (5WEW) and the Zn-dependent receptor-binding domain of Proteus mirabilis MR/P fimbrial adhesin MrpH (6Y4F). Toxicity prediction and drug likeness were predicted using ProTox-II and Molinspiration, respectively. A molecular dynamics (MD) simulation was carried out to study the protein ligand complexes. The methanolic leaves extract of B. monnieri revealed a 22.3 mm ± 0.6 mm to 25.0 mm ± 0.5 mm inhibition zone, while ethanolic extract seemed to produce 19.3 mm ± 0.8 mm to 23.0 mm ± 0.4 mm inhibition zones against K. pneumoniae with the use of increasing concentrations. In the case of P. mirabilis activity, the methanolic extracts showed a 21.0 mm ± 0.8 mm to 24.0 mm ± 0.6 mm zone of inhibition and the ethanol extract produced a 17.0 mm ± 0.9 mm to 23.0 mm ± 0.7 mm inhibition zone with increasing concentrations. Carbohydrates, flavonoids, saponin, phenolic, and terpenoid were common phytoconstituents identified in B. monnieri extracts. Oroxindin showed the best interactions with the binding energies with 5WEW and 6Y4F, -7.5 kcal/mol and -7.4 kcal/mol, respectively. Oroxindin, a bioactive molecule, followed Lipinski's rule of five and exhibited stability in the MD simulation. The overall results suggest that Oroxindin from B. monnieri can be a potent inhibitor for the effective killing of K. pneumoniae and P. mirabilis. Additionally, its safety has been established, indicating its potential for future drug discovery and development in the treatment for UTIs.

An In Silico Investigation to Explore Anti-Cancer Potential of Foeniculum vulgare Mill. Phytoconstituents for the Management of Human Breast Cancer.

Breast cancer is one of the most prevalent cancers in the world. Traditionally, medicinal plants have been used to cure various types of diseases and disorders. Based on a literature survey, the current study was undertaken to explore the anticancer potential of Foeniculum vulgare Mill. phytoconstituents against breast cancer target protein (PDB ID: 6CHZ) by the molecular docking technique. Molecular docking was done using Autodock/vina software. Toxicity was predicted by the Protox II server and drug likeness was predicted by Molinspiration. 100 ns MD simulation of the best protein-ligand complexes were done using the Amber 18 tool. The present molecular docking investigation has revealed that among the 40 selected phytoconstituents of F. vulgare, α-pinene and D-limonene showed best binding energy (-6 and -5.9 kcal/mol respectively) with the breast cancer target. α-Pinene and D-limonene followed all the parameters of toxicity, and 100 ns MD simulations of α-pinene and D-limonene complexes with 6CHZ were found to be stable. α-Pinene and D-limonene can be used as new therapeutic agents to cure breast cancer.

Phytoconstituents of traditional Himalayan Herbs as potential inhibitors of Human Papillomavirus (HPV-18) for cervical cancer treatment: An In silico Approach.

Human papillomavirus (HPV) induced cervical cancer is becoming a major cause of mortality in women. The present research aimed to identify the natural inhibitors of HPV-18 E1 protein (1R9W) from Himalayan herbs with lesser toxicity and higher potency. In this study, one hundred nineteen phytoconstituents of twenty important traditional medicinal plants of Northwest Himalayas were selected for molecular docking with the target protein 1R9W of HPV-18 E1 Molecular docking was performed by AutoDock vina software. ADME/T screening of the bioactive phytoconstituents was done by SwissADME, admetSAR, and Protox II. A couple of best protein-ligand complexes were selected for 100 ns MD simulation. Molecular docking results revealed that among all the selected phytoconstituents only thirty-five phytoconstituents showed the binding affinity similar or more than the standard anti-cancer drugs viz. imiquimod (-6.1 kJ/mol) and podofilox (-6.9 kJ/mol). Among all the selected thirty-five phytoconstituents, eriodictyol-7-glucuronide, stigmasterol, clicoemodin and thalirugidine showed the best interactions with a docking score of -9.1, -8.7, -8.4, and -8.4 kJ/mol. Based on the ADME screening, only two phytoconstituents namely stigmasterol and clicoemodin selected as the best inhibitor of HPV protein. MD simulation study also revealed that stigmasterol and clicoemodin were stable inside the binding pocket of 1R9W, Stigmasterol and clicoemodin can be used as a potential investigational drug to cure HPV infections.

Role of medicinal plants from North Western Himalayas as an efflux pump inhibitor against MDR AcrAB-TolC Salmonella enterica serovar typhimurium: In vitro and In silico studies.

ETHNOPHARMACOLOGICAL RELEVANCE: Zingiber officinale Roscoe has been utilized traditionally to cure various diseases like cold, cough, diarrhoea, nausea, asthma, vomiting, toothache, stomach upset, respiratory disorders, joint pain, and throat infection. It is also consumed as spices and ginger tea. AIM OF THE STUDY: The current study was aimed to identify the phytocompounds of traditional medicinal plants of North-Western Himalaya that could inhibit the AcrAB-TolC efflux pump activity of Salmonella typhimurium and become sensitive to antibiotic killing at reduced dosage. MATERIAL AND METHODS: Medicinal plant extracts were prepared using methanol, aqueous, and ethyl acetate and tested for efflux pump inhibitory activity of Salmonella typhimurium NKS70, NKS174, and NKS773 strains using Ethidium Bromide (EtBr)-agar cartwheel assay. Synergism was assessed by the agar well diffusion method and EPI activity by berberine uptake and EtBr efflux inhibition assays. Microdilution method and checkerboard assays were done to determine the minimum inhibitory concentration (MIC) and fractional inhibitory concentration index (FICI) respectively for a bioactive compound. To validate the phytocompound and efflux pump interaction, molecular docking with 6IE8 (RamA) and 6IE9 (RamR) targets was done using autoDock vina software. Toxicity prediction and drug-likeness were predicted by using ProTox-II and Molinspiration respectively. RESULTS: Methanolic and ethyl acetate extracts of P. integerrima, O. sanctum, C. asiatica, M. charantia, Z. officinale, and W. somnifera in combination with ciprofloxacin and tetracycline showed synergistic antimicrobial activity with GIIs of 0.61-1.32 and GIIs 0.56-1.35 respectively. Methanolic extract of Z. officinal enhanced the antimicrobial potency of berberine (2 to 4-folds) and increased the EtBr accumulation. Furthermore, bioassay-guided fractionation leads to the identification of lariciresinol in ethyl acetate fraction, which decreased the MIC by 2-to 4-folds. The ΣFIC values varied from 0.30 to 0.55 with tetracycline, that indicated synergistic/additive effects. Lariciresinol also showed a good binding affinity with 6IE8 (-7.4 kcal mol-1) and 6IE9 (-8.2 kcal mol-1), which is comparable to tetracycline and chenodeoxycholic acid. Lariciresinol followed Lipinski's rule of five. CONCLUSION: The data suggest that lariciresinol from Z. officinale could be a potential efflux pump inhibitor that could lead to effective killing of drug resistant Salmonella typhimurium at lower MIC. Molecular docking confirmed the antibacterial EPI mechanism of lariciresinol in Salmonella typhimurium and confirmed to be safe for future use.

Hydrogel composite containing azelaic acid and tea tree essential oil as a therapeutic strategy for Propionibacterium and testosterone-induced acne.

Azelaic acid (AzA) is a USFDA bioactive prescribed against acne vulgaris. It possesses delivery challenges like poor aqueous solubility, low skin-penetrability, and dose-dependent side effects, which could be overcome by its synergistic combination with tea tree oil (TTO) as a microemulsion (ME)-based hydrogel composite. AzA-TTO ME was prepared to employ pseudo-ternary phase diagram construction. The best AzA-TTO ME was of uniform size (polydispersity index < 0.7), nano-range (~357.4 ± 2% nm), transmittance (> 90%), and negative zeta potential (-1.42 ± 0.25% mV) values. ME hydrogel composite with optimum rheological and textural attributes showed better permeation, retention, and skin-compliant characteristics, vis-a-vis marketed formulation (Aziderm™) when evaluated in Wistar rat skin. In vitro antibacterial efficacy in bacterial strains, i.e., Staphylococcus aureus, Propionibacterium acne, and Staphylococcus epidermidis, was evaluated employing agar well plate diffusion and broth dilution assay. ME hydrogel has shown an increase in zone of inhibition by two folds and a decrease in minimum inhibitory concentration (MIC) by eightfold against P. acnes vis-a-vis AzA. Finally, ME hydrogel composite exhibited a better reduction in the papule density (93.75 ± 1.64%) in comparison to Aziderm™ 72.69 ± 4.67%) on acne as developed in rats by inducing testosterone. Thus, the developed AzA-TTO ME hydrogel composite promises an efficacious and comparatively safer drug delivery system for the topical therapy of acne vulgaris.

Antihypertensive activity of phytocompounds from selected medicinal plants via inhibition of angiotensin-converting enzyme (ACE) protein: an in-silico approach.

Hypertension has been a significant cause of death due to elevated blood pressure worldwide. The results of molecular docking showed out of selected 40 compounds, chasmanthin (-11.05 kcal/mol), and palmarin (-11.22 kcal/mol) showed strong binding with angiotensin-converting enzyme (ACE) target. The inhibitory action of the selected phytocompounds for ACE protein was also validated by comparing it with the reference drugs, lisinopril (-9.42 kcal/mol), and enalapril (-5.07 kcal/mol). MD simulations study of 100 ns also demonstrated stability of chasmanthin, and palmarin within the active sites of ACE protein. Molecular mechanics generalised born surface area (MMGBSA) analysis of MD trajectories exhibited significant binding of palmarin with ACE (dG Bind= -38.65 ± 2.59 kcal/mol) and chasmanthin (dG Bind= -37.64 ± 2.67 kcal/mol). Drug likeness and pharmacokinetics properties of palmarin and chasmanthin was also found to be permissible, thereby suggesting the use of chasmanthin and palmarin as a novel target inhibitor against ACE protein to combat hypertension.

Azelaic acid and Melaleuca alternifolia essential oil co-loaded vesicular carrier for combinational therapy of acne.

Aim: Azelaic acid (AzA), a comedolytic, antibacterial, anti-inflammatory anti-melanogenic agent, prescribed against acne vulgaris is safe on skin. Its combination with another widely used anti-acne agent, tea tree oil (EO) whose delivery is limited by volatility, instability and lipophilicity constraints was attempted. Method: Solvent injection was used to prepare AzA-EO integrated ethosomes. Result: Ethosomes were transformed into carbopol hydrogel, which exhibited pseudo-plastic properties with appreciable firmness, work of shear, stickiness and work of adhesion. The hydrogel showed better permeation and retention characteristics vis-a-vis commercial formulation (AzidermTM), when evaluated in Wistar rat skin. Further, ethosome hydrogel composite was better tolerated with no side effects. Conclusion: The findings suggests that the aforementioned strategy could be a potential treatment used for acne management.

Phytocompounds from Himalayan Medicinal Plants as Potential Drugs to Treat Multidrug-Resistant Salmonella typhimurium: An In Silico Approach.

Medicinal plants can be used as natural therapeutics to treat diseases in humans. Enteric bacteria possess efflux pumps to remove bile salts from cells to avoid potential membrane damage. Resistance to bile and antibiotics is associated with the survival of Salmonella enterica subspecies enterica serovar Typhimurium (S. typhimurium) within a host. The present study aimed to investigate the binding affinity of major phytocompounds derived from 35 medicinal plants of the North Western Himalayas with the RamR protein (PDB ID 6IE9) of S. typhimurium. Proteins and ligands were prepared using AutoDock software 1.5.6. Molecular docking was performed using AutoDock Vina and MD simulation was performed at 100 ns. Drug likeness and toxicity predictions of hit phytocompounds were evaluated using molinspiration and ProTox II online servers. Moreover, docking, drug likeness, and toxicity results revealed that among all the selected phytocompounds, beta-sitosterol exhibited the most efficacious binding affinity with RamR protein (PDB ID 6IE9) and was nontoxic in nature. MD simulation data revealed that beta-sitosterol in complex with 6IE9 can be used as an antimicrobial. Furthermore, beta-sitosterol is stable in the binding pocket of the target protein; hence, it can be further explored as a drug to inhibit resistance-nodulation-division efflux pumps.

Phytocompounds of Rheum emodi, Thymus serpyllum, and Artemisia annua Inhibit Spike Protein of SARS-CoV-2 Binding to ACE2 Receptor: In Silico Approach.

COVID-19, the disease caused by SARS-CoV-2, has been declared as a global pandemic. Traditional medicinal plants have long history to treat viral infections. Our in silico approach suggested that unique phytocompounds such as emodin, thymol and carvacrol, and artemisinin could physically bind SARS-CoV-2 spike glycoproteins (6VXX and 6VYB), SARS-CoV-2 B.1.351 South Africa variant of Spike glycoprotein (7NXA), and even with ACE2 and prevent the SARS-CoV-2 binding to the host ACE2, TMPRSS2 and neutrapilin-1 receptors. Since Chloroquine has been looked as potential therapy against COVID-19, we also compared the binding of chloroquine and artemisinin for its interaction with spike proteins (6VXX, 6VYB) and its variant 7NXA, respectively. Molecular docking study of phytocompounds and SARS-CoV-2 spike protein was performed by using AutoDock/Vina software. Molecular dynamics (MD) simulation was performed for 50ns. Among all the phytocompounds, molecular docking studies revealed lowest binding energy of artemisinin with 6VXX and 6VYB, with Etotal -10.5 KJ mol-1 and -10.3 KJ mol-1 respectively. Emodin showed the best binding affinity with 6VYB with Etotal -8.8 KJ mol-1and SARS-CoV-2 B.1.351 variant (7NXA) with binding energy of -6.4KJ mol-1. Emodin showed best interactions with TMPRSS 2 and ACE2 with Etotal of -7.1 and -7.3 KJ mol-1 respectively, whereas artemisinin interacts with TMPRSS 2 and ACE2 with Etotal of -6.9 and -7.4 KJ mol-1 respectively. All the phytocompounds were non-toxic and non-carcinogenic. MD simulation showed that artemisinin has more stable interaction with 6VYB as compared to 6VXX, and hence proposed as potential phytochemical to prevent SARS-CoV-2 interaction with ACE-2 receptor. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40495-021-00259-4.

Synergistic potential of essential oils with antibiotics to combat fungal pathogens: Present status and future perspectives.

The steady rise in the emergence of antibiotic-resistant fungal pathogens has rendered most of the clinical antibiotics available in the market to be ineffective. Therefore, alternative strategies are required to tackle drug-resistant fungal infections. An effective solution is to combine the available antibiotics with adjuvants such as phytochemicals or essential oils to enhance the efficacy and activity of antibiotics. The present review aims to summarize the studies on synergistic combinations of essential oils and anti-fungal antibiotics. The current findings, methods used for measuring synergistic effects, possible mechanisms of synergism, and future perspectives for developing synergistic EO-antibiotic therapeutic formulations are discussed in this study. Several essential oils exhibit synergistic effect in combination with antibiotics against human fungal pathogens such as Candida albicans. The possible mechanisms of synergy exhibited by essential oil- antibiotic combinations in fungi include disruption of cell wall structure/ ergosterol biosynthesis pathway, enhanced transdermal penetration of antibiotics, alterations in membrane permeability, intracellular leakage of cellular contents, inhibition of germ tube formation or fungal biofilm formation, and competition for a primary target. Synergistic combination of essential oils and antibiotics can prove to be a valid and pragmatic alternative to develop drugs with increased drug-efficacy, and low toxicity.

Identification of Potential Targets for Thymidylate Synthase and Amp-C ß-lactamase from Non-alkaloidal Fractions of Moringa oleifera Leaves.

AIM: The aim of present investigation is to identify the potential targets for Thymidylate Synthase and Amp-C ß-lactamase from non-alkaloidal fractions of Moringa oleifera leaves. BACKGROUND: Bioactive constituents from medicinal plants, either as pure compounds or as crude forms, provide vast opportunities for new drug discoveries. Due to an increasing demand for chemical diversity in screening programs, seeking therapeutic drugs from natural products, mainly from edible plants, has grown throughout the world. Moringa oleifera has an impressive range of medicinal uses with high nutritional value. Therefore, this medicinal plant has been used widely in traditional Indian medicine for anti-inflammation, anticancer and antibacterial infections. OBJECTIVES: The primary objective is to identify the phytoconstituents present in the maximum proportion in non-alkaloidal fractions of ethanolic leaf extract of Moringa oleifera. Then, the identified phytoconstituents were used to ensure the potential target molecules for binding affinity towards the target proteins viz. Thymidylate Synthase (1HVY) and Amp-C beta-lactamase (1FSY) by docking analysis. METHODS: In present investigation, ethanolic extract of Moringa leaves was prepared and then fractionated on the basis of presence/absence of alkaloids. The antimicrobial activity of different fractions of ethanolic leaf extract was evaluated against various pathogens. Later, after this, bioactive molecules present in the non-alkaloidal fractions of ethanolic leaf extract were accomplished through GC-MS analysis, and finally, the identified phytocompounds were analyzed through docking studies to evaluate their affinity for target proteins viz. Thymidylate Synthase (1HVY) and Amp-C ß-lactamase (1FSY). RESULTS: The antimicrobial activity of non-alkaloidal fractions of ethanolic leaf extract was evaluated against various pathogens which exhibited significant antimicrobial activity. Twenty phytocompounds were identified as gas chromatogram of non-alkaloidal fractions (chloroform and ethyl acetate) of leaf extract of M. oleifera; Four most prominent compounds having highest peak area percentage were identified as Ethane, 1,1,2,2-tetrachloro, (46.45%) 2-Propanone, 1,1,3-trichloro, (13.77%) Heptasiloxane, 1,1,3,3,5,5,7,7,9,9,11,11,13,13-tetradecamethyl (17.87%) and 2,4-Dichlorodiphenylsulfone (17.64%). Other notable compounds were 9,12-Octadecadienoic acid (Z,Z) (14.06%), Oleic acid, 3- (octadecyloxy)propyl ester (12.41%), Fluoranthene (6.98%), Phenol, 2,4-bis( 1,1-dimethylethyl) (4.16%) and Phthalic acid, butyl nonyl ester (3.47%). Only, five compounds viz. 2,6-Bis(1,1- dimethylethyl)phenol(C1), Dodecamethylcyclohexasiloxane(C2), Chlorodimethylethylsilane(C3), Fluoranthene(C4) and Hexadecanoic acid, methyl ester(C5) showed the maximum interaction with 1HVY with highest docking score of -178.51Kcal/mol, - 231.65Kcal/mol, -129.18Kcal/mol, - 173.10Kcal/mol and -220.78Kcal/mol, respectively. In addition, three compounds viz. Dodecamethylcyclohexasiloxane( C2), Fluoranthene(C4) and Hexadecanoic acid, methyl ester(C5) showed the maximum interaction with 1FSY with highest docking score of -137.23Kcal/mol, -54.34Kcal/mol and -153.84Kcal/mol, respectively. CONCLUSION: Moringa plant may provide incredible capabilities to develop pharmacological products. The present finding demonstrated that Moringa oleifera is an excellent plant candidate to be used for improving the health of communities.

Combination between antibacterial and antifungal antibiotics with phytocompounds of Artemisia annua L: A strategy to control drug resistance pathogens.

ETHNOPHARMACOLOGICAL RELEVANCE: Artemisia annua L. is a traditional Chinese medicine used for the treatment of malaria, jaundice and intense fever. AIM OF THE STUDY: The aim of the present study was to investigate the phytochemicals, antioxidants, antimicrobial and synergistic potential of methanolic and petroleum ether extracts of A. annua against bacterial and fungal pathogens. METHOD: Antioxidant activity of different concentrations of methanolic and petroleum ether extracts of A. annua was determined by DPPH free radical scavenging assay. Antimicrobial activity was determined by agar well diffusion, whereas MIC and synergistic activity was done by broth dilution method.TLC and GC-MS were done to identify active phytocompounds present in methanolic and petroleum ether extracts. RESULTS: Methanolic extract of A. annua showed higher antioxidant potential (IC50 37 0.75 ± 0.34 µg ml-1) as compared to petroleum ether extract. In antimicrobial analysis, methanolic and petroleum ether extracts of A. annua produced potent inhibitory activity against Candida strains as compared to bacterial strains. Methanolic and petroleum ether extracts of A. annua produced synergistic potential with decrease in MIC from 4 to 264 folds against bacterial (S. aureus and E. coli) and Candida strains in combination with antibacterial and antifungal antibiotics. Sub fraction I of methanolic and petroleum ether extracts was isolated through silica TLC and showed 10-fold more antimicrobial activity as compared to crude extract. GC-MS analysis of sub-fraction I of A. annua revealed 13 major phytocompounds with area more than 1%. Interestingly, 2-Propenoic acid and ridecyl ester (25.88%) were the major phytocompounds. CONCLUSION: Phytocompounds of A. annua can be used as bioenhancer of antibacterial and antifungal agents to control drug resistance.

In silico screening of hundred phytocompounds of ten medicinal plants as potential inhibitors of nucleocapsid phosphoprotein of COVID-19: an approach to prevent virus assembly.

Currently, there is no specific treatment to cure COVID-19. Many medicinal plants have antiviral, antioxidant, antibacterial, antifungal, anticancer, wound healing etc. Therefore, the aim of the current study was to screen for potent inhibitors of N-terminal domain (NTD) of nucleocapsid phosphoprotein of SARS-CoV-2. The structure of NTD of RNA binding domain of nucleocapsid phosphoprotein of SARS coronavirus 2 was retrieved from the Protein Data Bank (PDB 6VYO) and the structures of 100 different phytocompounds were retrieved from Pubchem. The receptor protein and ligands were prepared using Schrodinger's Protein Preparation Wizard. Molecular docking was done by using the Schrodinger's maestro 12.0 software. Drug likeness and toxicity of active phytocompounds was predicted by using Swiss adme, admetSAR and protox II online servers. Molecular dynamic simulation of the best three protein- ligand complexes (alizarin, aloe-emodin and anthrarufin) was performed to study the interaction stability. We have identified three potential active sites (named as A, B, C) on receptor protein for efficient binding of the phytocompounds. We found that, among 100 phytocompounds, emodin, aloe-emodin, anthrarufin, alizarine, and dantron of Rheum emodi showed good binding affinity at all the three active sites of RNA binding domain of nucleocapsid phosphoprotein of COVID-19.The binding energies of emodin, aloe-emodin, anthrarufin, alizarine, and dantron were -8.299, -8.508, -8.456, -8.441, and -8.322 Kcal mol-1 respectively (site A), -7.714, -6.433, -6.354, -6.598, and -6.99 Kcal mol-1 respectively (site B), and -8.299, 8.508, 8.538, 8.841, and 8.322 Kcal mol-1 respectively (site C). All the active phytocompounds follows the drug likeness properties, non-carcinogenic, and non-toxic. Theses phytocompounds (alone or in combination) could be developed into effective therapy against COVID-19. From MD simulation data, we found that all three complexes of 6VYO with alizarin, aloe-emodin and anthrarufin were stable up to 50 ns. These phytocompounds can be tested further for in vitro or in vivo and used as a potential drug to cure SARS-CoV-2 infection.Communicated by Ramaswamy H. Sarma.

Synergistic potential of Citrus aurantium L. essential oil with antibiotics against Candida albicans.

ETHNOPHARMACOLOGICAL RELEVANCE: Citrus aurantium L. is used in traditional medicine in India for treating stomach ache, vomiting, blood pressure, dysentery, diarrhea, cardiovascular analeptic, sedative, boils and urinary tract infections. Its essential oil from fruit peels has antioxidant, antimicrobial, antifungal, antiparasitic, and anti-inflammatory activities. AIM OF THE STUDY: The aim of the study was to characterize the antifungal activity and synergistic potential of essential oil extracted from leaves of Citrus aurantium L. of North-Western Himalayas against Candida albicans. MATERIALS AND METHODS: Citrus aurantium essential oil (CAEO) was extracted from leaves and characterized by GC-MS. The antifungal activity and synergistic potential of CAEO against C. albicans was studied by agar well diffusion, and broth microdilution assay. The anti-fungal potential of the phytoconstituents of CAEO was studied by in silico interaction with two fungal drug targets, N-myristoyl transferase (NMT) and Cytochrome P450 14 Alpha-sterol Demethylase (CYP51). RESULTS: CAEO exhibited strong antifungal activity against two strains of C. albicans, with fungicidal effect. The MIC of CAEO against C. albicans strains was 0.15 - 0.31% (v/v). CAEO exhibited synergistic potential with fluconazole and amphotericin B against C. albicans and enhanced the antifungal efficacy of the clinical drugs by 8.3 to 34.4 folds. The GC-MS analysis of CAEO identified at least ten compounds, with 2-ß pinene, δ-3 Carene and D-limonene as the major compounds. In silico molecular docking of the three major phytocompounds of CAEO with NMT and CYP51 revealed their potential to interact with both targets. δ-3 Carene showed best binding (Etotal of -131.13 kcal/mol) with NMT, while D-limonene exhibited highest binding energy (Etotal of -175.23 kcal/mol) with CYP51. ADME/T analysis showed that 2-ß pinene, δ-3 Carene and D-limonene exhibit drug likeliness and ideal toxicity profiles for their use as drug candidates. CONCLUSIONS: Thus, the essential oil from leaves of C. aurantium and its phytocomponents can be used as sustainable and natural therapeutic to treat candidiasis as well as a resource to enhance the potency of clinical antibiotics, which have lost efficacy due to emergence of drug resistance in C. albicans.

Bioassay guided fractionation of rhizome extract of Rheum emodi wall as bio-availability enhancer of antibiotics against bacterial and fungal pathogens.

ETHNOPHARMACOLOGICAL RELEVANCE: Rheum emodi Wall., is an important medicinal plant extensively used in Ayurvedic and Unani systems of traditional medicine. It is known to possess antioxidant, antibacterial, antifungal, anticancer, wound healing and immune enhancing activities. AIM OF THE STUDY: The aim of the current study was to investigate the antimicrobial activity and synergistic potential of different solvent fractions and phytocompounds of Rheum emodi rhizome against bacterial and fungal pathogens. MATERIAL AND METHODS: The antimicrobial and synergistic potential of the crude methanolic extract, different solvent fractions (n-hexane, chloroform, ethyl acetate, and residual aqueous) and isolated phytocompounds of the rhizome of Rheum emodi were assayed by broth microdilution method. The bioactive phytocompounds were isolated through silica TLC and quantified using HPTLC and HPLC. The bioactive phytocompounds were identified by LC-MS analysis. RESULTS: Phytochemical analysis of the sub-fractions showed that the TPC (417.94 ± 1.2 mg g-1 GAE) and TFC (187.40 ± 0.5 mg g-1 RE) were highest in residual aqueous extracts. The chloroform sub-fraction possessed the highest antimicrobial activity against bacterial (Escherichia coli, Staphylococcus aureus and Klebsiella pneumoniae) and fungal strains (Candida albicans MTCC 277 and ATCC 90028). The MIC of chloroform sub-fraction against S. aureus, K. pneumoniae, E. coli, C. albicans was 1.95, 3.91, 15.62 and 62.5 µg ml-1, respectively. TLC and LC-MS analysis of chloroform sub-fraction identified phytocompounds namely emodin D4 (m/z 274.262), rhein13c6 (m/z 290.176), chrysophanol dimethyl ether (m/z 282.291), and resveratrol (m/z 340.456). Quantification of emodin content showed that the chloroform sub-fraction (101.4543 µg mg-1, 194.8037 µg mg-1 measured through HPTLC and HPLC, respectively), and its TLC fraction (II) (75.18 µg mg-1, 232.384 µg mg-1 measured through HPTLC and HPLC, respectively) are rich in emodin. Furthermore, chloroform sub-fraction, its TLC fractions and emodin showed profound synergistic activity in combination with antibacterial and antifungal antibiotics and lowered the dosage of antibiotics by 4-257 folds. CONCLUSIONS: The bioassay guided fractionation of R. emodi rhizome methanolic extract identified phytocompounds (emodin, rhein13c6, chrysophanol dimethyl ether and resveratrol) that act as bioavailability enhancers of antibacterial and antifungal antibiotics, hence revealing their potential in treating multidrug resistance.