Antifouling activity and biodegradable potential of the bioactive metabolites isolated from mangrove Avicennia officinalis L.

The present study explores the antifouling potentials of ethanol extract of mangrove Avicennia officinalis. Results of antibacterial activity inferred that extract had strongly inhibited the growth of fouling bacterial strains with significant differences in halos (9-16 mm) and showed minimal bacteriostatic (12.5-100 µg ml-1) and bactericidal (25-200µg ml-1) values. It had also strenuously suppressed fouling microalgae with appreciable MIC (12.5 and 50 µg ml-1). The extract had also effectively deterred settlement of larvae of Balanus amphitrite and byssal thread of mussel Perna indica with lower EC50 (11.67 and 37.43 µg ml-1) and higher LC50 (257.33 and 817 µg ml-1) values. Further 100% recuperation of mussels from toxicity assay and therapeutic ratio of >20 substantiated its non-toxicity. GC-MS profile of bioassay guided fraction showed four (M1-M4) major bioactive metabolites. In silico biodegradability study revealed that metabolites M1 (Pentanoic acid, 5-methoxy-, phenyl ester) and M3 (Benzaldehyde, methyl-) have rapid biodegradation rates and eco-friendly in nature.

Exploring antimicrobial and biocompatible applications of eco-friendly fluorescent carbon dots derived from fast-food packaging waste transformation.

In the face of escalating environmental concerns, particularly the pervasive issue of non-biodegradable fast-food packaging waste, this study introduces a ground-breaking solution that not only addresses waste management but also advances biomedical technology. Utilizing the underexploited resource of Fucoidan, a sulfated polysaccharide from brown algae, we have innovatively transformed fast-food packaging waste into eco-friendly fluorescent carbon dots (FPCDs). These FPCDs were meticulously characterized through advanced techniques like FT-IR, TEM, and XRD, shedding light on their unique structure, morphology, and composition. A significant discovery of this study is the potent antimicrobial properties of these FPCDs, which demonstrate remarkable effectiveness against specific bacterial and fungal strains. This opens new avenues in the realm of biomedical applications, including imaging, drug delivery, and biosensing. Furthermore, extensive toxicity assessments, including the Brine shrimp lethality assay and Adult Artemia toxicity tests, underscore the safety of these nanoparticles, bolstering their applicability in sensitive medical scenarios. Our research presents a compelling dual approach, ingeniously tackling environmental sustainability issues by repurposing waste while simultaneously creating valuable materials for biomedical use. This dual benefit underscores the transformative potential of our approach, setting a precedent in both waste management and medical innovation.

Unraveling bioactive metabolites of mangroves as putative inhibitors of SARS-CoV-2 Mpro and RBD proteins: molecular dynamics and ADMET analysis.

COVID-19 is a deadly pandemic caused by Corona virus leading to millions of deaths worldwide. Till today no medicine was available to cure this disease. This study selected 262 potential bioactive natural products derived from mangroves to inhibit the main protease (Mpro) and receptor-binding domain (RBD) protein of the COVID-19 virus. All the ligands were subjected to Adsorption Digestion Metabolism Excretion and Toxicity (ADMET) predictions and docking studies using AutodockVina. Among all the ligands, NP_143 (Shearinine A) and NP_242 (Amentoflavone), having the highest docking score of 10.2 and 10.1 Kj/mole, respectively, were picked for 100 ns of Molecular Dynamics using GROMACS. The trajectories generated were used to estimate Root mean square deviation (RMSD), Root mean square fluctuations (RMSF), Radius of Gyrations (RG), Solvent accessible surface area (SASA), and Hydrogen bonds. From the data generated, both the ligands have good binding ability at the active site of Mpro protein and do not deviate much. They have strong interactions with the amino acids during the 100 ns of simulations and can thus be considered potential drug candidates.Communicated by Ramaswamy H. Sarma.

HIGHLIGHTSSARS-CoV-2 Mpro plays a pivotal role in viral replication and serves as important drug target.Bioactive compounds of mangroves origin are promising source of antiviral drugs.ADMET and docking study explored two lead compounds from mangroves against Mpro.MD simulation validated ligands of lead compounds had stronger binding affinity with Mpro.

Environmentally benign, bright luminescent carbon dots from IV bag waste and chitosan for antimicrobial and bioimaging applications.

Luminescent carbon dots have gained significant attention in various fields due to their unique optical properties and potential applications. Here, the study was aimed to propose a novel and sustainable approach for the synthesis of luminescent carbon dots (ICDs) using IV (Intravenous) medical bag waste. The ICDs were synthesized through a facile and cost-effective method that involved the carbonization of IV bag waste followed by surface functionalization with chitosan. The synthesized ICDs were characterized using UV-Visible spectrum (UV-Vis), Fourier Transform Infrared Spectroscopy (FT-IR), X-Ray Diffraction analysis (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The size of the ICDs is between 2 and 8 nm. The ICDs effectively inhibited the growth of both gram positive and gram negative bacterial strains with the inhibitory activity in the range of 11-14 mm and 12-18 mm, respectively. Results of antibiofilm activity of ICDs varying concentrations (50 and 100 µg/ml) showed that it effectively distorted the biofilm architecture and thereby validated its promising potentials. In vitro antioxidant activity showed remarkable DPPH radical scavenging potentials of ICDs (33.4%-70.1%). Results of MTT assay revealted that ICDs showed potent cytotoxic effect on HeLa cells in a dose dependant matter (25-400 µg/ml). Furthermore, when HeLa cells were excited at wavelengths of 380 nm, 440 nm and 540 nm, cell-imaging experiments using ICDs revealed the presence of blue, green, and red fluorescence. This innovative method not only addresses the issue of IV bag waste in a sustainable manner but also opens up exciting possibilities for the advancement of versatile carbon-based materials in the field of biomedicine.

Harnessing actinobacteria potential for cancer prevention and treatment.

Actinobacteria are gram-positive bacteria with high G:C ratio in their genetic makeup. They have been noted and studied for their capacity to produce bioactive substances with a range of uses in human health, and they also exhibit a unique property of adapting to extreme environments quite well. Actinobacteria may play an essential role in cancer prevention and treatment due to their synthesis of anticancer compounds, as indicated by recent studies. The aim of this review is to give a summary of what is currently known about the connection between actinobacteria and different types of cancer. This paper delineates the diverse array of actinobacterial bioactive compounds possessing anticancer properties, elucidates their mechanisms of action and explores potential applications in cancer treatment. Furthermore, this review highlights how the microbiome influences the onset and progression of cancer, as well as the discussing the potential benefits that actinobacteria may bring in terms of controlling the microbiome and contributing to the regulation of the tumour microenvironment to cure or prevent cancer.

Screening, partial purification of antivibriosis metabolite sterol-glycosides from Rhodococcus sp. against aquaculture associated pathogens.

The present study probed the antimicrobial potential of a rare mangrove associated actinomycetes against an array of aquatic bacterial pathogens causing disease outbreak in fin and shellfish. Antibacterial activity results implied that the mangrove associated actinomycetes RAS7 exhibited striking inhibitory activity against the tested aquatic bacterial pathogens. Identification of strain RAS7 through polyphasic and 16S rRNA sequencing affirmed that the strain belongs to Rhodococcus sp. Optimization of culture conditions for antibacterial activity by Rhodococcus sp. inferred that it grew well and exerted notable antagonistic activity in medium supplied with 1% galactose and peptone as carbon and nitrogen sources. Similarly, the strain grown in 0.1% tyrosine, 1% NaCl, pH 7.5 and temperature 35 °C recorded maximum bioactivity against the test pathogens. The crude ethyl acetate extract of Rhodococcus sp. at 200  µg/ml recorded markedly pronounced growth inhibitory activity ranged between 14 and 29 mm. The cytotoxic effect of crude extract against brine shrimp Artemia salina nauplii registered LC50 value of 134.294 µg/ml after 24 h of exposure. The secondary metabolite was separated using Ethyl acetate: Methanol (7:3) as solvent system through TLC. The TLC autobiogram mapped the active spot in TLC with Rf value of 0.84. Analysis of chemical constituents and FT-IR spectral analysis substantiated that the active principle in bioassay guided fraction was sterol-glycosides.

Explication of the Potential of 2-Hydroxy-4-Methoxybenzaldehyde in Hampering Uropathogenic Proteus mirabilis Crystalline Biofilm and Virulence.

Proteus mirabilis is an important etiological agent of catheter-associated urinary tract infections (CAUTIs) owing to its efficient crystalline biofilm formation and virulence enzyme production. Hence, the present study explicated the antibiofilm and antivirulence efficacies of 2-hydroxy-4-methoxybenzaldehyde (HMB) against P. mirabilis in a non-bactericidal manner. HMB showed concentration-dependent biofilm inhibition, which was also evinced in light, confocal, and scanning electron microscopic (SEM) analyses. The other virulence factors such as urease, hemolysin, siderophores, and extracellular polymeric substances production as well as swimming and swarming motility were also inhibited by HMB treatment. Further, HMB treatment effectively reduced the struvite/apatite production as well as crystalline biofilm formation by P. mirabilis. Furthermore, the results of gene expression analysis unveiled the ability of HMB to impair the expression level of virulence genes such as flhB, flhD, rsbA, speA, ureR, hpmA, and hpmB, which was found to be in correlation with the results of in vitro bioassays. Additionally, the cytotoxicity analysis divulged the innocuous characteristic of HMB against human embryonic kidney cells. Thus, the present study reports the potency of HMB to act as a promising therapeutic remedy for P. mirabilis-instigated CAUTIs.

Environmentally benign antifouling activity and toxic properties of bioactive metabolites from mangrove Excoecaria agallocha L.

This study was aimed to investigate the antifouling (AF) potentials and toxic properties of methanol extract from leaves of mangrove Excoecaria agallocha. Antimicrofouling activity results inferred that this extract strongly inhibited fouling bacterial and microalgal growth. This extract had also inhibited the settlement of brown mussel Perna indica and larvae of barnacle Balanus amphitrite. Further, EC50 < LC50 and therapeutic ratio > 1 together propagated non-toxic nature of the extract. Mollusk foot adherence assay result showed complete inhibition of foot spreading and loss of attachment of common rocky fouler Patella vulgata to the substrata. Field assay results affirmed that this extract effectively deterred settlement of biofoulers. Purification and GC-MS analysis of bioassay-guided active spot evidenced presence of three major compounds (> 85%) responsible for the promising AF activity. The identified lead compounds subjected to an estimation (BIOWIN™) program developed by United States Environmental Protection Agency (USEPA) predicts that they are biodegradable in nature. Graphical abstract.

In vitro-Scientific evaluation on antimicrobial, antioxidant, cytotoxic properties and phytochemical constituents of traditional coastal medicinal plants.

In the present study, evaluation of antimicrobial, antioxidant, phytochemical constituents and toxicological properties of six coastal medicinal plants (CMP's) such as Ipomea biloba, Cantharanthus roseus, Cymbopogon citratus, Vitex negundo, Thespesia populnea and Pandanus tectorius was done. The maximum antimicrobial activity was recorded by methanolic extracts of V. negundo and T. populnea against bacterial and fungal pathogens. Similarly, methanolic extracts of V. negundo and T. populnea evidenced highest antioxidant properties. The extract of T. populnea showed the maximum cytotoxicity against Artemia salina with the LC50 value of 478.11µg/ml. The hemolytic property of CMP's extracts was V. negundo (8.91%), T. populnea (21%) and C. citratus (64%) also the hemolytic index did not show any hemolysis of human erythrocytes. Furthermore, the TLC separation of V. negundo and T. populnea extracts exhibited the presence of Flavonoids (Rf-0.74) and Terpenoids (Rf-0.64). The present findings propose the promising clinical applications of selected CMP's.

Antifouling and toxic properties of the bioactive metabolites from the seagrasses Syringodium isoetifolium and Cymodocea serrulata.

The present study documents the antifouling and toxic properties of seagrasses Syringodium isoetifolium and Cymodocea serrulata. For that, the seagrasses S. isoetifolium and C. serrulata were extracted individually using organic solvents viz. dichloromethane, acetone and methanol. Amongst the extracts, the maximum antimicrofouling and antimacrofouling activities were exhibited by methanol extracts of both the seagrasses. The Minimal Inhibitory Concentration (MIC) of methanolic extracts of seagrasses was ranged from 1.0 to 10µg/ml against test biofilm bacteria and microalgal strains. Similarly, 100% fouling inhibition of limpet Patella vulgata was found at 6.0mg/ml of methanolic extracts of seagrasses. The mussel Perna indica showed 50% of byssal production and attachment inhibition at 21.51±2.03, 17.82±1.07µg/ml and the anticrustaecean activity for 50% mortality of Artemia salina was recorded at 732.14±9.21 and 394.16±5.16µg/ml respectively for methanolic extracts of S. isoetifolium and C. serrulata. The minimal inhibitory and higher lethal concentrations of active methanol extracts shows it׳s less toxic nature. Based on the prolific results, methanol extracts of S. isoetifolium and C. serrulata were subjected to purification using silica gel column and thin layer chromatography. Then the active compounds of the bioassay guided fractions were partially characterized using gas chromatography coupled with mass spectroscopy (GC-MS) and keyed out that fatty acids (C16 to C24) were the major components which responsible for the antifouling properties of the candidate seagrasses.

Influence of probiotic bacterium Bacillus cereus isolated from the gut of wild shrimp Penaeus monodon in turn as a potent growth promoter and immune enhancer in P. monodon.

A probiotic bacterium isolated from the gut of wild shrimp Penaeus monodon rendered maximum antagonistic activity against shrimp pathogens and was capable of producing extracellular enzymes. The probiotic bacterium was identified as Bacillus cereus through 16S rRNA sequencing. The lyophilized B. cereus was supplemented with shrimp basal diet at four different concentrations (0.1­0.4%/100 g feed) in D1­D4 diets. The viability of probiotic bacterium in the test diets was evaluated during the study period at various time intervals. The viability ranged from 50.24 ± 1.42 to 180.34 ± 1.30 CFU/g in D1 to D3 diets on the 30th day, whereas it was slightly declined from 45.23 ± 1.30 to 169.13 ± 1.18 CFU/g during the 90th day of storage. A control diet (C), devoid of probiotic supplementation was also simultaneously prepared. During experimentation, P. monodon postlarvae (PL-15) were cultured in individual one tonne capacity FRP tanks in triplicates provided with equal amount of substratum (clay soil) and fed with these respective diets at ad libitum for 90 days. Survival was high (82.0 ± 1.60%) in D4 diet fed shrimp as against a low survival of 65.0 ± 1.33% displayed by control diet fed shrimp. Overall growth responses inferred that a maximum production of 10.45 ± 0.275 g, SGR of 4.40 ± 0.179% and a better FCR of 1.27 ± 0.081 were obtained in D4 diet fed shrimp. However, the water quality parameters showed nonsignificant (P > 0.05) variations among the control and the probiotic treated groups. The tested immunological parameters such as Total haemocyte count, phenoloxidase activity, respiratory burst activity, lysozyme activity, plasma protein concentration and bactericidal activity were higher in D4 diet fed P. monodon, when compared to that of other diets fed shrimp. It is therefore suggested that lyophilized probiotic B. cereus at a concentration of 0.4%/100 g feed was efficient in stimulating the growth and immunity in shrimp.

Optimization of bacteriocin production by Lactobacillus sp. MSU3IR against shrimp bacterial pathogens.

BACKGROUND: Aquaculture is one amongst the growing and major food producing sectors. Shrimp culture is one of the subsectors of aquaculture that attracts more attention because of the economic interest. However, the shrimp culture systems have been facing severe consequences and economical losses due to disease outbreaks. Risk of disease outbreak can be combated with the application of probiotics. For economically viable production of such probiotic products, the present study provides information on the optimization and partial purification of bacteriocin produced by a goat milk isolate Lactobacillus sp. MSU3IR against the shrimp bacterial pathogens. RESULTS: Bacteriocin production was estimated as a measure of bactericidal activity (arbitrary Unit/ml) over the test strains. The optimum culture conditions and media components for maximum bacteriocin production by Lactobacillus sp. MSU3IR were: pH: 5.0, temperature: 30°C, carbon source: lactose; nitrogen source: ammonium acetate; NaCl: 3.0% and surfactant: Tween 80. MRS medium was found to extend better bacteriocin production than other tested media. Upon partial purification of bacteriocin, the SDS-PAGE analysis had manifested the presence of two peptide bands with the molecular weight of 39.26 and 6.38 kDa, respectively. CONCLUSION: The present results provide baseline trend for the statistical optimization, scale up process and efficient production of bacteriocin by the candidate bacterial strain Lactobacillus sp. MSU3IR which could be used to replace the usage of conventional chemotherapeutics in shrimp culture systems.

Antipyretic, wound healing and antimicrobial activity of processed shell of the marine mollusc Cypraea moneta

Objective: Some of the products derived from marine organisms have been recommended in alternative system of medicine especially Siddha medicine for several treatments. Among the marine molluscs, Cypraea moneta shell has been used as siddha medicine from ancient days. But no systematic study has been done on its efficacy as antipyretic, wound healing and as antimicrobial agent. In the present study, the protective action of processed shell powder of C. moneta was evaluated by us in an animal model for the above treatments. Methods: C. moneta shell powder was prepared by standard method described in Siddha medicine. Then the antipyretic, wound healing as well as antimicrobial effect of the processed powder was tested in Wister albino rats. Results: By the intravenous injection of yeast cell suspension into albino rats, the antipyretic effect of the shell powder given orally was studied by various concentrations of 0, 10, 20 and 30 mg/ml. The body temperature of the albino rat became normal within a short duration (3h). The wound healing effect of the shell powder was very effective. In the thigh region 2 cm wound was made and the different dosages of shell powder (C -Control, SD - Single dose, DD -Double dosage and TD -Triple dose/day) were applied externally as ointment. The scar was produced in eighth day onwards in DD and TD. Antimicrobial activity was studied in three different oppurtunistic human pathogens such as Micrococcus sp., Proteus vulgaris andSalmonella abory in different concentrations (2, 3, 4 and 5% w/v) of C. moneta shell powder extract. Among these, Proteus vulgaris showed the maximum zone of inhibition (15mm size) against 5% w/v concentration, followed by Micrococcus sp. (12mm) and S. abory (10mm) against the same concentration. Conclusions: The present observation suggested that, processed C. moneta shell powder can be used as an alternative medicine, and it has antipyretic, wound healing as well as antimicrobial properties.