In vitro and in silico evaluation of antimicrobial properties of Delphinium cashmerianum L., a medicinal herb growing in Kashmir, India

ETHNOPHARMACOLOGICAL RELEVANCE

Microorganisms are developing resistance to synthetic drugs. As a result, the search for novel antimicrobial compounds has become an urgent need. Medicinal plants are commonly used as traditional medicine and Delphinium is one of the prominent genus used in the treatment of several diseases.

AIM OF THE STUDY

The present study aimed to determine the in vitro and in silico antimicrobial activities of petroleum ether, ethyl acetate and methanol extracts from the leaf samples of plant (Delphinium cashmerianum L.) against various bacterial and fungal strains.

MATERIAL AND METHODS

Three extracts of Delphinium cashmerianum prepared and 88 bioactive compounds were analyzed through LC-MS data with the vast majority of them having therapeutic applications. These extracts have been screened for the antimicrobial activity against various bacterial (Escherichia coli, Micrococcus luteus, Klebsiella pneumoniae, Streptococcus pneumonia, Haemophilus influenzae, Neisseria mucosa) and fungal (Candida albicans, Candida glabrata, Candida paropsilosis) species through in silico molecular docking approach using autodock vina software, molecular dynamic simulation (MDS), in vitro disc diffusion and broth microdilution method for minimum inhibitory concentration (MIC) evaluation.

RESULTS

Our results demonstrated that all three extracts were active against the whole set of microorganisms. The ethyl acetate extract was the most active against S.pneumonia, K. pneumoniae and C. albicans with a minimum inhibitory concentration (MIC) value of 6.25, 25 and 50 μg/ml, respectively. The petroleum ether and methanol extracts were active against S.pneumonia and N.mucosa with MIC values of 25 and 50 μg/ml. Furthermore, we also performed the in silico virtual screening of all these compounds obtained from LC-MS data analysis against various known drug targets of bacterium and fungi. Upon analysis, we obtained 5 compounds that were efficiently binding to the drug targets. However, after performing exhaustive molecular docking and molecular dynamic simulation (MDS) analysis, it was observed that Daidzein compound is bound to drug targets more efficiently.

CONCLUSION

The results showed that these plant extracts exhibit antimicrobial activity and ethyl acetate extract proved to exhibit the most effective antibacterial and antifungal properties.

Nanoceria laden decellularized extracellular matrix-based curcumin releasing nanoemulgel system for full-thickness wound healing

Decellularized extracellular matrix (ECM) has been widely used for wound healing. But, ECM failed to integrate tissue and restore the tissue function properly, when elevated levels of free radicals and biofilm formation occur at the wound site. Here, nanoemulgel systems were fabricated, considering the combinatorial approach of nanotechnology (nanoceria and curcumin nanoemulsion) and ECM gel of goat small intestine submucosa. The curcumin was encapsulated in the nanoemulgel system to enhance bioavailability in terms of antibacterial, antioxidant, sustained release and permeation at the wound site. Nanoceria was also incorporated to enhance the antibacterial, antioxidant and wound healing properties of the fabricated nanoemulgel formulation. All the formulations were porous, hydrophilic, biodegradable, antioxidant, antibacterial, hemocompatible, biocompatible, and showed enhanced wound healing rate. The formulation (DG-SIS/Ce/NC) showed the highest free radicals scavenging capacity and antibacterial property with prolonged curcumin release (62.9% in 96 h), skin permeability (79.7% in 96 h); showed better cell growth under normal and oxidative-stressed conditions: it also showed full-thickness wound contraction (97.33% in 14 days) with highest collagen synthesis at the wound site (1.61 μg/mg in 14 days). The outcomes of this study suggested that the formulation (DG-SIS/Ce/NC) can be a potential nanoemulgel system for full-thickness wound healing application.

Repurposing of Mycobacterium indicus pranii for the severe form of COVID -19 patients in India: A cohort study

SARS-CoV-2 induces the production of proinflammatory cytokines, which results in cytokine storm, and immune-modulators like Mycobacterium indicus pranii (MIP) might ameliorate COVID -19 related cytokine storm. Therefore, the present study evaluates whether MIP offers an advantage in the treatment of severe COVID -19 patients infected with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Prospective MIP cohort Study was conducted in chest disease hospitals in Srinagar, Jammu and Kashmir, India. In the present prospective, randomized clinical study, critically severe COVID -19 patients were divided into two groups, the MIP group (n=105) and Best Standard Treatment group (n=210). Procalcitonin, Ferritin, Hs-CRP (High Sensitive C Reactive Protein), D-dimer levels and Interleukin levels on 5^th -day post-treatment were significantly reduced in the MIP group compared to the BST group. Compared to the BST group, 105 consecutive patients with severe COVID -19 in the MIP group reported early weaning off mechanical ventilation, resolution of chest architecture (CT scan), significant increase in SpO₂ levels and decreased mortality with hazard ratio-0.234 (95% CI-0.264-2.31) (p-value-0.001). MIP restored SpO₂ , immune/inflammatory response, normalized lung abnormalities (Chest CT scan), and reduced mortality without any serious complications. However, there is a need for placebo-controlled double-blind and controlled clinical trials to confirm the efficacy. This article is protected by copyright. All rights reserved.

An update on emerging therapeutics to combat COVID-19

BACKGROUND

The COVID-19 pandemic has demanded effective therapeutic protocol from researchers and clinicians across the world. Currently, a large amount of primary data have been generated from several preclinical studies. At least 300 clinical trials are underway for drug repurposing against COVID-19; the clinician needs objective evidence-based medication to treat COVID-19.

OBSERVATIONS

Single-stranded RNA viral genome of SARS-CoV-2 encodes structural proteins (spike protein), non-structural enzymatic proteins (RNA-dependent RNA polymerase, helicase, papain-like protease, 3-chymotrypsin-like protease) and other accessory proteins. These four enzymatic proteins on spike protein are rate-limiting steps in viral replications and, therefore, an attractive target for drug development against SARS-CoV-2. In silico and in vitro studies have identified various potential epitomes as candidate sequences for vaccine development. These studies have also revealed potential targets for drug development and drug repurposing against COVID-19. Clinical trials utilizing antiviral drugs and other drugs have given inconclusive results regarding their clinical efficacy and side effects. The need for angiotensin-converting enzyme (ACE-2) inhibitors/angiotensin receptor blockers and corticosteroids has been recommended. Western countries have adopted telemedicine as an alternative to prevent transmission of infection in the population. Currently, no proven, evidence-based therapeutic regimen exists for COVID-19.

CONCLUSION

The COVID-19 pandemic has put tremendous pressure on researchers to evaluate and approve drugs effective against the disease. Well-controlled randomized trials should assess medicines that are not marketed with substantial evidence of safety and efficacy and more emphasis on time tested approaches for drug evaluation.

Organoids: A new approach in toxicity testing of nanotherapeutics

Nanotechnology has revolutionized diverse fields, which include agriculture, the consumer market, medicine, and other fields. Widespread use of nanotechnology-based products has led to increased prevalence of these novel formulations in the environment, which has raised concerns regarding their deleterious effects. The application of nanotechnology-based formulations into clinical use is hampered by the lack of the availability of effective in vitro systems, which could accurately assess their in vivo toxic effects. A plethora of studies has shown the hazardous effects of nanoparticle-based formulations in two-dimensional in vitro cell cultures and animal models. These have some associated disadvantages when used for the evaluation of nano-toxicity. Organoid technology fills the space between existing two-dimensional cell line culture and in vivo models. The uniqueness of organoids over other systems for evaluating toxicity caused by nano-drug formulation includes them being a co-culture of diverse cell types, dynamic flow within them that simulates the actual flow of nanoparticles within biological systems, extensive cell-cell, cell-matrix interactions, and a tissue-like morphology. Thus, it mimics the actual tissue microenvironment and, subsequently, provides an opportunity to study drug metabolism and toxico-dynamics of nanotechnology-based novel formulations. The use of organoids in the evaluation of nano-drug toxicity is in its infancy. A limited number of studies conducted so far have shown good predictive value and efficiently significant data correlation with the clinical trials. In this review, we attempt to introduce organoids of the liver, lungs, brain, kidney intestine, and potential applications to evaluate toxicity caused by nanoparticles.

Ameliorative effects of Cuscuta reflexa and Peucedanum grande on letrozole induced polycystic ovary syndrome in Wistar rats

Objectives

The current study was designed to examine the therapeutic role of hydroalcoholic extract of Cuscuta reflexa Roxb (CRE) and Peucedanum grande C.B. Clarke (PGE) on letrozole (1 mg/kg) induced polycystic ovary syndrome (PCOS) in female Wistar albino rats.

Methods

PCOS rats were treated with CRE (280 mg/kg), PGE (140 mg/kg) or CRE + PGE p.o. for 3 weeks. Vaginal smears for phase of estrous cycle determination, serum levels of sex androgens, lipid profile, oxidative stress parameters and histopathology of ovarian tissues were investigated.

Results

Diestrous cycle days treated with CRE (group III) or PGE (group IV) decreased significantly (p < 0.05) compared to PCOS control animals (group II). Moreover, weight of uteri in PCOS animals treated with the plant extracts also increased significantly (p < 0.05) compared to that of group II animals. Histopathological examination showed the protective effect of the CRE and PGE indicated by the disappearance of ovarian cyst.

Conclusion

The study demonstrated that the CRE and PGE either alone or in combination hold a significant effect in letrozole induced PCOS rat models and could be useful in the management of reproductive and metabolic disorders related to PCOS.

In vitro potency of 2-(((2-hydroxyphenyl)amino)methylene)-5,5-dimethylcyclohexane-1,3-dione against drug-resistant and non-replicating persisters of Mycobacterium tuberculosis

OBJECTIVES

New antituberculosis agents active against drug-resistant and non-replicating tubercle bacilli are required. We evaluated a previously identified hit, 2-(((2-hydroxyphenyl)amino)methylene)-5,5-dimethylcyclohexane-1,3-dione (PAMCHD), against several clinical Mycobacterium tuberculosis isolates, including multidrug-resistant (MDR) strains and non-replicating drug-tolerant persisters of M. tuberculosis H37Rv.

METHODS

PAMCHD's potential against drug-resistant M. tuberculosis was investigated by broth microdilution. CFU enumeration was performed to determine PAMCHD's activity against five types of dormant bacilli.

RESULTS

No significant differences in MICs of PAMCHD were observed against M. tuberculosis H37Rv (2.5-5 µg/mL) and eight drug-susceptible strains (1.25-5 µg/mL) as well as drug-resistant strains including six isoniazid (INH)-resistant (2.5-10 µg/mL), one INH + ethambutol (EMB)-resistant (5 µg/mL), one rifampicin (RIF) + EMB-resistant (5 µg/mL) and three MDR (2.5-10 µg/mL) strains. Thus, PAMCHD maintains activity against all kinds of clinical strains, especially MDR. Regarding drug-tolerant persisters, INH and RIF killed, respectively, 0.5 and 5.0 log10 CFU of non-replicating persisters developed by hypoxia and 1.5 and 2.5 log₁₀ CFU developed by nutrient starvation at 64 × of their respective MIC against actively dividing cultures. In contrast, PAMCHD sterilised persister cultures developed by hypoxia (killed 6.5 log10 CFU) or starvation (killed 7.5 log10 CFU). PAMCHD sterilised RIF-tolerant (tolerance level up to 100 µg/mL of RIF) 100-day-old static persisters at 64 × MIC, while moxifloxacin killed only 1.0 log10 CFU of these persisters at 64 × MIC.

CONCLUSION

PAMCHD offers significant potential against MDR-TB and exhibits notable potency against non-replicating drug-tolerant M. tuberculosis persisters. These findings warrant further studies of PAMCHD for further anti-TB drug development.

Medicinal plants: Treasure for antiviral drug discovery

The pandemic of viral diseases like novel coronavirus (2019-nCoV) prompted the scientific world to examine antiviral bioactive compounds rather than nucleic acid analogous, protease inhibitors, or other toxic synthetic molecules. The emerging viral infections significantly associated with 2019-nCoV have challenged humanity's survival. Further, there is a constant emergence of new resistant viral strains that demand novel antiviral agents with fewer side effects and cell toxicity. Despite significant progress made in immunization and regenerative medicine, numerous viruses still lack prophylactic vaccines and specific antiviral treatments that are so often influenced by the generation of viral escape mutants. Of importance, medicinal herbs offer a wide variety of therapeutic antiviral chemotypes that can inhibit viral replication by preventing viral adsorption, adhering to cell receptors, inhibiting virus penetration in the host cell, and competing for pathways of activation of intracellular signals. The present review will comprehensively summarize the promising antiviral activities of medicinal plants and their bioactive molecules. Furthermore, it will elucidate their mechanism of action and possible implications in the treatment/prevention of viral diseases even when their mechanism of action is not fully understood, which could serve as the base for the future development of novel or complementary antiviral treatments.

Factors affecting wool characteristics of sheep reared in Kashmir

This study was conducted on 82,908 records of purebred and upgraded Kashmir Merino sheep to evaluate the performance of breed over the years. The data pertaining to fiber diameter (FD), staple length (SL), clean wool yield percent (CWY %), number of crimps/cm (NCPC), and medullation percent (MP) spread over a period of 15 years (2013-2017) was collected from Fleece Testing Laboratory Nowshera, Srinagar. The highest CV (%) was observed for MP, whereas the lowest CV (%) was observed for FD (2.07%). The least-squares means were 20.96 ± 0.002 μm, 4.05 ± 0.01 cm, 66.68 ± 0.01%, 4.38 ± 0.02 No/cm and 0.79 ± 0.05% for FD, SL, CWY (%), NCPC and MP, respectively. The year of shearing had highly significant (p < 0.01) effect on all the traits under the study. The study concludes that crossbreeding with exotic fine wool breeds has resulted improved genetic potential of native germplasm with respect to wool quality traits with Merino sheep performing better in the agro-climatic conditions of the State. Environment was also found to play a significant role in expression of wool quality traits during the period of the study.

Molecular characterization, computational analysis and expression profiling of Dmrt1 gene in Indian major carp, Labeo rohita (Hamilton 1822)

Sexual dimorphism of fish morphology, physiology and behavior is diverse and complex in nature. Doublesex and mab-3 related transcription factor (Dmrt) is a large protein family whose function is sexual development and differentiation in vertebrates. Here, we report a full-length cDNA sequence of Labeo rohita (rohu) Dmrt1 of 907 bp length having 798 bp of open reading frame encoding 265 amino acids. The molecular weight of rohu DMRT1 protein was found to be 28.74 KDa and isoelectric point was 7.53. DMRT1 protein contains 23 positively and 24 negatively charged amino acids with a GRAVY score of -0.618. A characteristic DM domain was found in DMRT1 protein, which is a novel DNA-binding domain. Phylogenetic analysis showed maximum similarity with Cyprinus carpio when compared with DMRT1 of other vertebrates. Molecular docking study identified active sites to be targeted for drug designing. Rohu DMRT1 was observed to interact with other proteins such as FOXL2, CYP19a1a, AMH and SOX9a. Differential expression study revealed higher expression in testis tissue implying its role in male sex differentiation and testicular development. The information generated in the present work could facilitate further research to resolve the issues related to gonadal maturation and reproduction of commercially important aquaculture species.

In vitro bactericidal activity of 3-cinnamoyl-4-hydroxy-6-methyl-2-pyrone (CHP) against drug-susceptible, drug-resistant and drug-tolerant isolates of Mycobacterium tuberculosis

OBJECTIVES

Tuberculosis (TB) poses a serious global threat to humans. New bactericidal agents that can shorten treatment duration and target drug resistance still remain a top priority in the discovery of anti-TB drugs. The objective of this study was to investigate the bactericidal potential of 3-cinnamoyl-4-hydroxy-6-methyl-2-pyrone (CHP) against drug-susceptible, drug-resistant clinical isolates and drug-tolerant Mycobacterium tuberculosis.

METHODS

The minimum bactericidal concentration (MBC) was determined by colony-forming unit (CFU) enumeration. The kill curve analysis was done at different concentrations spanning over 16 days. Drug combination studies with antituberculosis drugs were done to investigate possible synergy. The potential against drug- resistant isolates of M. tuberculosis was done by broth dilution assay. CFU enumeration was done to determine its activity against nutrient-starved drug tolerants, and its feasibility for oral administration was tested by serum inhibitory titre.

RESULTS

CHP displayed bactericidal activity with an MBC of 4 μg/mL against M. tuberculosis H37Rv. The kill curve analysis exhibited a biphasic pattern of killing. CHP showed synergy with rifampicin, isoniazid and amikacin but was indifferent towards ethambutol and levofloxacin. CHP retained its full activity against drug-susceptible, monoresistant and multidrug-resistant (MDR) clinical isolates. CHP showed very strong bactericidal activity against nondividing, drug-tolerant M. tuberculosis that on comparison was highly superior to rifampicin. Furthermore, CHP significantly improved the bactericidal activity of rifampicin and isoniazid in a combination study. The serum inhibitory titre in mice indicated its high oral bioavailability.

CONCLUSION

Our results show strong bactericidal potential of CHP against M. tuberculosis that warrant its immediate mechanistic, pharmacokinetic and pharmacodynamic studies.

Enterotoxin gene profile and molecular epidemiology of Aeromonas species from fish and diverse water sources

AIMS

This investigation was undertaken to study the prevalence, enterotoxin gene profile and molecular epidemiology of Aeromonads from various sources of water (182) and fish (173).

METHODS AND RESULTS

A total of 116 Aeromonas sp. were isolated, of which 48 (26·37%) were from water and 68 (34·62%) were from fish samples collected from retail markets and fish farms. The Aeromonads were recovered from all types of water sources viz. drinking water (13%), surface waters (26%) and fish ponds (69%). The most prevalent species recovered from drinking water was A. hydrophila, from fish ponds it was A. caviae, from surface water sources A. hydrophila and A. caviae were recovered more frequently, and A. hydrophila and A. veronii bv. sobria were isolated predominantly from gills of fish samples. On multiplex PCR analysis for the detection of enterotoxin genes (act, alt, ast), the above mentioned Aeromonas species frequently contained enterotoxin genes, irrespective of their sources. From isolates across all the sources, act (63%) and alt (57%) genes were encountered more frequently than ast (6%). The enterobacterial repetitive intergenic consensus sequences polymerase chain reaction was used for typing of isolates and most of the isolates from water and fish were related, owing to similar ecosystem.

CONCLUSION

A wide distribution of enterotoxin genes in Aeromonads from water and fish is a potential public health threat and molecular genotyping can be helpful to study epidemiology of the pathogen.

SIGNIFICANCE AND IMPACT OF THE STUDY

A high proportion of isolates recovered from diverse water sources, particularly potable drinking water and fish samples carried one or more enterotoxin genes thereby indicating a potential pathogenic nature of isolates from these sources. The genetic relatedness was detected amongst many isolates recovered from water sources and fish samples indicating circulation of familiar virulent clones in the aquatic environments.

Determination of prevalence, serological diversity, and virulence of Dichelobacter nodosus in ovine footrot with identification of its predominant serotype as a potential vaccine candidate in J&K, India

The aim of this study was to determine the prevalence, serological diversity, and virulence of Dichelobacter nodosus in footrot lesions of sheep and identification of its predominant serotype as a potential vaccine candidate. The overall prevalence of footrot in sheep was 16.19%, and ranged from 13.69 to 19.71%, respectively. A total of 759 flocks with 22,698 sheep were investigated for footrot and 2374 clinical samples were collected from naturally infected sheep exhibiting footrot lesions. Of the 2374 samples collected, 1446 (60.90%) were positive for D. nodosus by polymerase chain reaction (PCR). These positive samples when subjected to serogroup-specific multiplex PCR, 1337 (92.46%) samples carried serogroup B, 247 (17.08%) possessed serogroup E, 86 (5.94%) serogroup I, and one (0.069%) serogroup G of D. nodosus. While mixed infection of serogroups B and E was detected in 127 (8.78%), B and I in 46 (3.18%) and B, E, and I in 26 (1.79%) samples, respectively. The serogroup B of D. nodosus was the predominant (92.47%) serogroup affecting sheep population with footrot followed by serogroup E (19.91%) and serogroup I (4.57%), respectively. Virulent status of D. nodosus strains were confirmed by presence of virulence-specific integrase A (intA) gene and the production of thermostable proteases. The intA gene was detected in 709 (72.79%) samples while gelatin gel test carried out on 246 representative isolates all positive for intA gene produced thermostable proteases, confirming their virulence nature. The PCR-restriction fragment length polymorphism (PCR-RFLP) of whole fimA gene of serogroup B revealed the predominance of serotype B5 (82.97%) of serogroup B. This information suggests that serotype B5 is the predominant serotype of D. nodosus associated with severe footrot lesions in sheep in Jammu & Kashmir (J&K), India. Hence, this serotype can be a potential vaccine candidate for the effective control and treatment of ovine footrot.

In vitro evaluation of dinactin, a potent microbial metabolite against Mycobacterium tuberculosis

Current long duration treatment options and the emergence of drug resistance in tuberculosis (TB) have led to renewed interest in discovery of novel anti-tubercular agents or the scaffolds exhibiting enhanced efficacy with current anti-TB drugs. Herein, dinactin, a potent bioactive macrotetrolide isolated from Streptomyces puniceus AS13, was evaluated against Mycobacterium tuberculosis H37Rv and other susceptible and drug-resistant clinical isolates of M. tuberculosis. In vitro pharmacological assays showed that dinactin is bactericidal against laboratory standard strain M. tuberculosis H37Rv (minimum inhibitory concentration [MIC] 1 µg/mL and minimum bactericidal concentration [MBC] 4 µg/mL). Dinactin also retained its activity against various clinical isolates, including multidrug-resistant strains of M. tuberculosis. Whole cell interaction assays with standard first- and second-line anti-TB drugs showed the synergistic interaction of dinactin with rifampicin or amikacin, reflecting its suitability for use in combination regimens. The killing kinetics studies of dinactin against M. tuberculosis H37Rv revealed that it has strong concentration-dependent anti-TB activity that is also dependent on time. The kill curve also showed dynamic killing capacity of dinactin as it exhibited bactericidal potential at all concentrations tested. Kill curve data demonstrated that dinactin, like isoniazid, exerts its strong tuberculocidal activity within the first two days of exposure. This evidence strongly supports further evaluation of dinactin as a new option in the treatment of TB.

Synthesis and in vitro evaluation of substituted 3-cinnamoyl-4-hydroxy-pyran-2-one (CHP) in pursuit of new potential antituberculosis agents

Tuberculosis is an ever-evolving infectious disease that urgently needs new drugs. In the search for new antituberculosis agents, a library of 3-cinnamoyl-4-hydroxy-6-methyl-2H-pyran-2-ones (CHPs) (2a-2y) was synthesized and evaluated against a standard virulent laboratory strain of Mycobacterium tuberculosis H37Rv. Out of 25 compounds, 11, 5, 7 and 2 (2a and 2u) showed least, moderate, good and appreciable activities, respectively, based on minimum inhibitory concentrations (MICs). Both 2a and 2u exhibited an MIC value of 4 μg ml^-1, which was close to those of standard antituberculosis drugs ethambutol, streptomycin and levofloxacin. Neither 2a nor 2u showed any activity against Gram-positive or Gram-negative bacteria and even against non-tuberculous mycobacterium, i.e. Mycobacterium smegmatis. Thus, like the antituberculosis drugs rifampicin, isoniazid and pretomanid, they are highly TB specific. All the pyrone-based chalcones showed no recognizable level of cytotoxicity against normal human kidney cell line (HEK-293) up to 80 μM concentration and 11 exhibited an IC₅₀ ≤ 100 μM (highest tested concentration). On further investigation, both 2a and 2u proved to be nontoxic against four human cell lines but 2a proved to be a better choice as it did not reach IC₅₀ even at 100 μM (highest tested concentration) while the IC₅₀ of 2u was around 80 μM. In conclusion, our results demonstrate that 2a is specific against M. tuberculosis with no appreciable toxicity; its activity matches that of some clinically approved antituberculosis drugs and it therefore merits further evaluation.

The synthesis, biological evaluation and structure-activity relationship of 2-phenylaminomethylene-cyclohexane-1,3-diones as specific anti-tuberculosis agents

The present study utilised whole cell based phenotypic screening of thousands of diverse small molecules against Mycobacterium tuberculosis H37Rv (M. tuberculosis) and identified the cyclohexane-1,3-dione-based structures 5 and 6 as hits. The selected hit molecules were used for further synthesis and a library of 37 compounds under four families was synthesized for lead generation. Evaluation of the library against M. tuberculosis lead to the identification of three lead antituberculosis agents (37, 39 and 41). The most potential compound, 2-(((2-hydroxyphenyl)amino)methylene)-5,5-dimethylcyclohexane-1,3-dione (39) showed an MIC of 2.5 μg mL^-1, which falls in the range of MICs values found for the known antituberculosis drugs ethambutol, streptomycin and levofloxacin. Additionally, this compound proved to be non-toxic (<20% inhibition at 50 μM concentration) against four human cell lines. Like first line antituberculosis drugs (isoniazid, rifampicin and pyrazinamide) this compound lacks activity against general Gram positive and Gram negative bacteria and even against M. smegmatis; thereby reflecting its highly specific antituberculosis activity.

Cell wall: A versatile fountain of drug targets in Mycobacterium tuberculosis

Tuberculosis is the leading infectious disease responsible for an estimated one and a half million human deaths each year around the globe. HIV-TB coinfection and rapid increase in the emergence of drug resistant forms of TB is a dangerous scenario. This underlines the urgent need for new drugs with novel mechanism of action. A plethora of literature exist that highlight the importance of enzymes involved in the biosynthesis of mycobacterial cell wall responsible for its survival, growth, permeability, virulence and resistance to antibiotics. Therefore, assembly of cell wall components is an attractive target for the development of chemotherapeutics against Mycobacterium tuberculosis. The aim of this review is to highlight novel sets of enzyme inhibitors that disrupt its cell wall biosynthetic pathway. These include the currently approved first and second line drugs, candidates in clinical trials and current structure activity guided endeavors of scientific community to identify new potent inhibitors with least cytotoxicity and better efficacy against emergence of drug resistance till date.

Antimicrobial investigation of selected soil actinomycetes isolated from unexplored regions of Kashmir Himalayas, India

The aim of the present study was to isolate and evaluate the antimicrobial potential of soil actinomycetes of Kashmir Himalayas. The secondary metabolites of actinomycetes are the prominent source of antibiotics. A total of 121 morphologically different actinomycete strains were isolated and screened for antimicrobial activity against various human pathogens. The ethyl acetate extract of fermented broth an actinomycete strain, identified as Streptomyces pratensis exhibited significant antimicrobial activity against Staphylococcus aureus ATCC 29213 with MIC 0.25 μg/ml and Mycobacterium tuberculosis Strain H37Rv with MIC 0.062 μg/ml. The strain S. pratensis IIIM06 was grown on large scale and their broth was extracted with ethyl acetate. The extract was subjected to various chromatography techniques which led to the isolation of four compounds whose structures were established as actinomycin C1, actinomycin C2, actinomycin C3 and actiphenol on the basis of spectral data analysis. Actinomycin C1, C2 and C3 exhibited potent antimicrobial activity against S. aureus as well as M. tuberculosis. The isolated indigenous actinomycetes exhibited good antibacterial activity and the study reveals that IIIM06 is a promising strain and could be of great potential for industrial applications.

α-pyrones: Small molecules with versatile structural diversity reflected in multiple pharmacological activities-an update

The investigations in the chemistry and biology of α-pyrone (2-pyrone) are of vital importance as they constitute an essential pharmacophore in many naturally occurring and biologically active synthetic agents. They are a promising class of biorenewable platform chemicals that provide access to an array of chemical products and intermediates. Literature survey reveals that a simple change in the substitution pattern on the 2-pyrone ring system often leads to diverse biological activities. In this review, we present a brief overview of 2-pyrone pharmacophore followed by highlighting their pharmacological properties and potential applicability till date. Particular attention is focused on the distinctive chemotherapeutic activities of 2-pyrones as anti-HIV, anti-TB and anti-cancer agents followed by their potential role against neurodegeneration, hypercholesterolemia, microbial infections, chronic obstructive lung disease, inflammation, antinociception and immunomodulation. Since 2005, when 2-pyrones came in limelight, their detailed pharmacological activities have been well documented. This review has mainly been prepared on the basis of original reports published in recent two decades with an aim to attract the attention of researchers towards this versatile scaffold for future endeavors that may lead to the development of potential drug candidates against above diseases.

Discovery of anti-microbial and anti-tubercular molecules from Fusarium solani: an endophyte of Glycyrrhiza glabra

AIMS

Glycyrrhiza glabra is a high-value medicinal plant thriving in biodiversity rich Kashmir Himalaya. The present study was designed to explore the fungal endophytes from G. glabra as a source of bioactive molecules.

METHODS AND RESULTS

The extracts prepared from the isolated endophytes were evaluated for anti-microbial activities using broth micro-dilution assay. The endophytic strain coded as A2 exhibiting promising anti-bacterial as well as anti-tuberculosis activity was identified as Fusarium solani by ITS-5.8S ribosomal gene sequencing technique. This strain was subjected to large-scale fermentation followed by isolation of its bioactive compounds using column chromatography. From the results of spectral data analysis and comparison with literature, the molecules were identified as 3,6,9-trihydroxy-7-methoxy-4,4-dimethyl-3,4-dihydro-1H-benzo[g]isochromene-5,10-dione (1), fusarubin (2), 3-O-methylfusarubin (3) and javanicin (4). Compound 1 is reported for the first time from this strain. All the four compounds inhibited the growth of various tested bacterial strains with MIC values in the range of <1 to 256 μg ml^-1 . Fusarubin showed good activity against Mycobacterium tuberculosis strain H37Rv with MIC value of 8 μg ml^-1 , whereas compounds 1, 3 and 4 exhibited moderate activity with MIC values of 256, 64, 32 μg ml^-1 , respectively.

CONCLUSIONS

To the best of our knowledge, this is the first study that reports significant anti-tuberculosis potential of bioactive molecules from endophytic F. solani evaluated against the virulent strain of M. tuberculosis. This study sets background towards their synthetic intervention for activity enhancement experiments in anti-microbial drug discovery programme.

SIGNIFICANCE AND IMPACT OF THE STUDY

Due to the chemoprofile variation of same endophyte with respect to source plant and ecoregions, further studies are required to explore endophytes of medicinal plants of all unusual biodiversity rich ecoregions for important and or novel bioactive molecules.

Isolation and characterization of three benzylisoquinoline alkaloids from Thalictrum minus L. and their antibacterial activity against bovine mastitis

ETHNO-PHARMACOLOGICAL RELEVANCE

The roots of Thalictrum minus are traditionally used in the treatment of inflammation and infectious diseases such as bovine mastitis. However, there are no reports available in literature till date regarding the antibacterial studies of T. minus against bovine mastitis.

AIM OF THE STUDY

The present study was undertaken to evaluate the antibacterial potential of crude extract of T. minus (root) and some of its isolated constituents against bovine mastitis in order to scientifically validate its traditional use.

MATERIALS AND METHODS

A total of three alkaloid compounds were isolated from the DCM: MeOH extract of roots of T. minus using silica gel column chromatography. Structural elucidation of the isolated compounds was done by using spectroscopic techniques like mass spectrometry and NMR spectroscopy. Pathogens were isolated from cases of bovine mastitis and identified by using 16S rRNA gene sequencing. The broth micro-dilution method was used to evaluate the antibacterial activities of DCM: MeOH extract and isolated compounds against mastitis pathogens.

RESULTS

The three isolated compounds were identified as benzylisoquinoline alkaloids (1) 5'-Hydroxythalidasine, (2) Thalrugosaminine and (3) O-Methylthalicberine. Compounds (2) and (3) are reported for the first time from the roots of T. minus. Five mastitis pathogens viz., Staphylococcus xylosus, Staphylococcus lentus, Staphylococcus equorum, Enterococcus faecalis and Pantoea agglomerans were identified on the basis of sequence analysis of isolates using the nucleotide BLAST algorithm. This study reports for the first time the isolation and molecular characterization of mastitis pathogens from Kashmir valley, India. The DCM: MeOH extract exhibited broad spectrum antibacterial activities that varied between the bacterial species (MIC=250-500µg/ml). 5'-Hydroxythalidasine and Thalrugosaminine showed promising antibacterial activity with MIC values of 64-128µg/ml while Staphylococcus species were found to be the most sensitive strains.

CONCLUSIONS

The antibacterial activities of the DCM: MeOH extract and isolated compounds support the traditional use of T. minus in the treatment of bovine mastitis.

Molecular characterization of kisspeptin gene and effect of nano-encapsulted kisspeptin-10 on reproductive maturation in Catla catla

Kisspeptin, a member of the RF-amide-related peptide family, has emerged recently as an essential gatekeeper of various reproductive processes via its ability to activate kisspeptin receptors at puberty. In this study, the kiss1 gene and its receptor kiss1rb were cloned and characterized from the brain of Catla catla. Further, the effects of kissppetin-10 (K-10) and chitosan-encapsulated K-10 nanoparticles (CK-10) on gene expression were assessed. The full-length complementary DNA sequence of kiss1 is 754 bp with an open reading frame of 351 bp that encodes a putative protein of 116 amino acids. The kiss1rb complementary DNA is 1,280 bp long and contains a 5'-untranslated region of 30 bp, 3'-untranslated region of 149 bp, and an open reading frame (open reading frame) of 1,101 bp. The expression patterns of kiss1 and kiss1rb messenger RNA (mRNA) in basal tissues revealed that they are mainly expressed in the brain, pituitary gland, and gonads. CK-10 nanoparticles with a particle size of 125 nm and a zeta potential of 36.45 mV were synthesized and compared with K-10. Chitosan nanoparticles showed 60% entrapment efficiency for K-10. The mRNA expression of reproductive genes (GnRH, LH, and FSH) in fish injected with K-10 declined after 6 h, whereas those injected with CK-10 showed controlled and a sustained surge of mRNA expression of these genes with a peak at 12 h. Histologic examination of ovaries indicated a pronounced effect of CK-10 on maturation and gonadal development. The study reports that this sustained release delivery system will help in increasing the half-life of K-10 and other therapeutic protein drugs in the biological system. Besides, the nanoformulation developed in the present study may be useful for developing therapies against various reproductive dysfunctions in vertebrates.

Diarrhoeagenic Escherichia coli and salmonellae in calves and lambs in Kashmir absence, prevalence and antibiogram

Polymerase chain reaction assays and culture were used to investigate 728 faecal samples from 404 calves (286 diarrhoeic, 118 healthy) and 324 lambs (230 diarrhoeic, 94 healthy) in Kashmir, India, for the presence of enterotoxigenic Escherichia coli (ETEC), enteroaggregative E. coli (EAEC), diffusely adherent E. coli (DAEC) and salmonellae. Antimicrobial sensitivity patterns were also investigated. In total, 23 ETEC isolates were obtained from the diarrhoeic calves and 12 from diarrhoeic lambs. Most (74%) of the isolates from calves harboured the gene encoding heat-labile enterotoxin I, whereas 75% of the isolates from lambs possessed only the gene encoding for heat-stable enterotoxin a. The ETEC isolates belonged to 20 serogroups, among which serogroups O15 (five isolates) and O8 (four isolates) were the most frequent. Salmonella Typhimurium or S. Enteritidis was identified in three samples from diarrhoeic lambs. The ETEC isolates and the salmonellae showed multidrug resistance. No EAEC or DAEC was detected in any of the samples.

Non-specificity of primers used for PCR based serogrouping of Dichelobacter nodosus and identification of a novel D. nodosus strain

The present study records the first case of non-specificity of typing primers developed by Dhungyel et al. A strain of Dichelobacter nodosus (JKS-20G) isolated from ovine footrot in Kashmir, India, showed specificity for serogroup C and G primers. The fimA sequence of the strain turned out to be closer to serogroup G than C. The nucleotide sequence showed maximum homology of 92% with that of serotype G1 strain 238 and 95% with partial sequence available for serotype G2 strain VCS 1004. However, the deduced amino acid sequence of the fimbrial subunit gene of JKS-20G differed from strain 238 by 16 amino acids and by four amino acids from that of partial sequence of strain VCS 1004. This variation indicates towards declaring this isolate as a new serotype (G3) but just insufficient to classify this into a new serogroup. Some of the amino acid substitutions were located within three hypervariable regions a characteristic of different serogroups. However, to ascertain whether this isolate deserves a new serotype status, there is a need to go for antigenic characterisation of this isolate using the tube and cross tube agglutination test.

Putative Virulence Genes and Biofilm Production Among Typical Enteroaggregative Escherichia coli Isolates from Diarrhoeic Children in Kashmir and Andhra Pradesh

Fifty-eight typical EAEC isolates from children with diarrhoea were examined for HEp-2 cell adherence assay, presence of dispersin (aap), yersiniabactin (irp2), plasmid encoded toxins (pet), Shigella enterotoxin1 (set1A) and cryptic open reading frame (shf) putative virulence genes by polymerase chain reaction as well as for biofilm production. All the isolates showed aggregative adherence pattern on HEp-2 cells. All but five isolates (91.3 %) carried aap gene. While irp2, pet, set1A and shf genes were detected in 68.9, 5.1, 39.6, and 60.3 % isolates, respectively. Thirty-three (64.7 %) isolates out of 51 tested were found to produce biofilm which was found to be significantly associated only with set1A virulence gene (P = 0.025). Highest amount of biofilm was produced by a strain that possessed all the genes studied. Out of 14 isolates in which the most frequent gene combination (aap, irp2 and shf) was observed, only six produced biofilm. It is concluded that there is significant heterogeneity in putative virulence genes of EAEC isolates from diarrhoeic children and biofilm formation is associated with multiple genes.