Antibacterial potential of sponge endosymbiont marine Enterobacter sp at Kavaratti Island, Lakshadweep archipelago

ObjectiveTo isolate antibacterial potential of sponge endosymbiotic bacteria from marine sponges at Lakshadweep archipelago. Also to identify the potent bacteria by 16s rDNA sequencing and determine the antibacterial activity against clinical pathogens by MIC.MethodsSponge samples was collected from sub-tidal habitats at Kavaratti Island and identified. The endosymbiotic bacteria were isolated and selected potential bacteria which show antibacterial activity in preliminary screening against clinical pathogens Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), Salmonella typhi (S. typhi), Klebsiella pneumoniea (K. pneumoniea) and Streptococcus sp. by disc diffusion assay. The crude extracts of potential bacteria LB3 was tested against clinical pathogens by MIC. The LB3 strain was identified by 16s rDNA sequencing, 1 111 bp was submitted in NCBI (HQ589912) and constructed phylogenetic tree.ResultsSponge sample was identified as Dysidea granulosa (D. granulosa) and potential bacteria LB3 identified as Enterobacter sp TTAG. Preliminary screening of sponge isolates against clinical pathogens, LB3 strain was selected as potential producer of secondary metabolites and crude extract was implies on MIC of LB3 have confirmed with lowest concentration of 5.0 mg/mL in broth medium influence of crude extract on growth inhibitory activity after 5 h of incubation period and completed the inhibitory activity at 15 h.ConclusionsThe present study concluded that phylogenetic analysis of endosymbiotic bacteria Enterobacter sp from sponge D. granulosa of Lakshadweep islands showed significant antibacterial activity against clinical bacterial pathogens.     

Evaluation of antibacterial activity of selected medicinal plant extracts from south India against human pathogens

ObjectiveThe present study was to evaluate the antibacterial properties of 21 crude extracts from leaf and flower of Aristolochia indica (A. indica), Cassia angustifolia (C. angustifolia), leaf of Catharanthus roseus (C. roseus), Diospyros melanoxylon (D. melanoxylon), Dolichos biflorus (D. biflorus), Gymnema sylvestre (G. sylvestre) and Justicia procumbens (J. procumbens).MethodsThe ethyl acetate, acetone and methanol extract of medicinal plants were evaluated against Gram-positive Bacillus cereus (B. cereus) and Gram-negative bacteria Aeromonas hydrophila (A. hydrophila), Enterobacter aerogenes (E. aerogenes), Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) by using well diffusion assay and minimum inhibitory concentration (MIC).ResultsThe crude plant extracts demonstrated broad spectrum activity against all bacteria. The highest inhibitory zone was observed in leaf methanol extract of A. indica against E. aerogenes (25 mm), and E. coli (20 mm), flower methanol extract of C. angustifolia against B. cereus (22 mm) and leaf acetone extract of G. sylvestre against B. cereus (22mm). The MIC values of leaf methanol extract of A. indica against K. pneumonia (22.6μg/ml), and flower extract showed against E. coli (MIC: 24.2μg/ml), leaf ethyl acetate extract of C. angustifolia against K. pneumoniae (MIC: 28.4μg/ml). Acetone ethyl acetate and methanol extracts of D. melanoxylon and D. biflorus showed the lowest MIC activity value of >30 μg/ml against all tested pathogens.ConclusionThe antibacterial activity could be confirmed in most species used in traditional medicine in South India. Nevertheless, traditional knowledge might provide some leads to elucidate potential candidates for future development of new antibiotic agents.     

ZnO Semiconductor Nanoparticles and Their Application in Photocatalytic Degradation of Various Organic Dyes

The biosynthesis of oxide semiconductor nanoparticles (NPs) using materials found in nature opens a wide field of study focused on sustainability and environmental protection. Biosynthesized NPs have the capacity to eliminate organic dyes, which pollute water and cause severe damage to the environment. In the present work, the green synthesis of zinc oxide (ZnO) NPs was carried out using Capsicum annuum var. Anaheim extract. The photocatalytic elimination of methylene blue (MB), methyl orange (MO), and Rhodamine B (RhB) in UV radiation was evaluated. The materials were characterized by scanning and transmission electron microscopy (SEM and TEM) and SEM-coupled energy dispersive spectroscopy (EDS), attenuated total reflectance-infrared (ATR-IR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Photoluminescence (PL), and ultraviolet-visible spectroscopy (UV-Vis). The TEM analysis showed the NPs have an average size of 40 nm and quasi-spherical shape. ATR-IR showed the ZnO NPs contained functional groups from the extract. The analysis through XRD indicated that the NPs have a hexagonal zincite crystal structure with an average crystallite size of approximately 17 nm. The photoluminescence spectrum (PL) presented an emission band at 402 nm. From the UV-Vis spectra and TAUC model, the band-gap value was found to be 2.93 eV. Finally, the photocatalytic assessment proved the ZnO NPs achieved 100% elimination of MB at 60 min exposure, and 85 and 92% degradation of MO and RhB, respectively, at 180 min. This indicates that ZnO NPs, in addition to using a friendly method for their synthesis, manage to have excellent photocatalytic activity in the degradation of various organic pollutants.     

Zinc Oxide Nanoparticles for Water Purification

In this study, zinc oxide nanoparticles were synthesized through a simple co-precipitation method starting from zinc acetate dihydrate and sodium hydroxide as reactants. The as-obtained ZnO nanoparticles were morphologically and structurally characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photocatalytic activity, and by determining the antimicrobial activity against Gram-negative and Gram-positive bacteria. The XRD pattern of the zinc oxide nanoparticles showed the wurtzite hexagonal structure, and its purity highlighted that the crystallinity correlated with the presence of a single product, zinc oxide. The ZnO nanoparticles have an average crystallite size of 19 ± 11 nm, which is in accordance with the microscopic data. ZnO nanoparticles were tested against methyl orange, used as a model pollutant, and it was found that they exhibit strong photocatalytic activity against this dye. The antibacterial activity of ZnO nanoparticles was tested against Gram-negative and Gram-positive strains (Escherichia coli, Staphylococcus aureus, and Candida albicans). The strongest activity was found against Gram-positive bacteria (S. aureus).     

Preliminary study on the antibacterial activity of some medicinal plants of Khuzestan (Iran)

ObjectiveTo search for antimicrobial agents among natural products.MethodsEthanolic extracts of 4 plant species, including Beta vulgaris L. (Chenopodiaceae), Amaranthus graecizans (A. graecizans) L. (Amaranthaceae), Rumex obtusifolius (R. obtusifolius) L. and Polygonum patulum (P. patulum) M.B. (Polygonaceae), were evaluated for antibacterial activity using agar disc diffusion method against some gram-positive and gram-negative bacteria [Pseudomonas aeruginosa (P. aeruginosa), Listeria monocytogenes (L. monocytogenes), Staphylococcus epidermidis (S. epidermidis), Staphylococcus aureus (S. aureus), Klebsiella pneumoniae (K. pneumoniae), Salmonella typhi (S. typhi), Bacillus cereus (B. cereus), Bacillus anthracis (B. anthracis), Escherichia coli (E. coli) and Streptococcus pyogenes (Str. pyogenes)]. These extracts were obtained from aerial parts of the used plants.ResultsThe majority of these extracts had inhibitory effect at different concentrations (0.05 g/mL, 0.10 g/mL, 0.20 g/mL and 0.40 g/mL) against above mentioned bacteria. E. coli was the most resistant strain. The highest inhibitory zone was showed by ethanolic extract of P. patulum against Str. pyogenes (28 mm) and followed by ethanolic extract of B. vulgaris against S. epidermidis (23 mm). The extract of A. graecizans didn't show inhibitory activity except at 0.40 g/mL against B. cereus. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of R. obtusifolius extract that was measured against Str. pyogenes were equal (MIC=MBC=5.00mg/mL).ConclusionThe findings of this study could also be as new source for antibiotics discovery and infection treatment.     

Antimicrobial activity of the ethanolic and aqueous extracts of Salacia chinensis Linn. against human pathogens

ObjectiveTo investigate antimicrobial effects of ethanolic and aqueous extracts of Salacia chinensis (S. chinensis) Linn. against pathogenic bacteria and fungi.MethodsThe Staphylococcus aureus (S. aureus) (MTCC 96), Staphylococcus epidermidis (S. epidermidis) (MTCC 435), Bacillus subtilis (B. subtilis) (MTCC 121), Escherichia coli (E. coli) (MTCC 443), Klebsiella pneumoniae (K. pneumoniae) (MTCC 432), Proteus mirabilis (P. mirabilis) (MTCC 1429), Salmonella paratyphi A (S. paratyphi A) (MTCC 735), Salmonella typhimurium (S. typhimurium) (MTCC 98), Shigella flexneri (S. flexneri) (MTCC 1457) and Pseudomonas aeruginosa (P. aeruginosa) (MTCC 424), Candida albicans (C. albicans) (MTCC 183) and Cryptococcus neoformans (C. neoformans) (clinical isolate) were originally obtained from Microbial Type Culture Collection Centre, Institute of Microbial Technology, Chandigarh, India. Antimicrobial activity was carried out by disc diffusion and broth dilution methods against pathogens by using crude ethanolic and aqueous extracts.ResultsEthanolic extract of S. chinensis L. leaves showed significant antimicrobial activity against S. epidermidis (33.20 mm), C. albicans (30.40 mm) and C. neoformans (18.20 mm) mean values were documented. Aqueous extract of leaves showed significant inhibitory activity against C. neoformans (19.8 mm) and S. epidermidis (17.80 mm) were observed. Based on broth dilution method, the ethanolic extract of crude plant material showed the minimum inhibitory concentration (MIC) values against S. epidermidis, C. neoformans (256 μg/mL) and C. albicans (512 μg/mL), whereas the aqueous extract of S. chinensis L. leaves showed significant inhibitory activity against S. epidermidis (512 μg/mL) and C. neoformans (1024 μg/mL) were observed.ConclusionsThe present result revealed that ethanolic extract of S. chinensis L. possesses significant antifungal activity when compared as the antibacterial activities.     

Improving the Inhibitory Effect of Phages against Pseudomonas aeruginosa Isolated from a Burn Patient Using a Combination of Phages and Antibiotics

Antibiotic resistance causes around 700,000 deaths a year worldwide. Without immediate action, we are fast approaching a post-antibiotic era in which common infections can result in death. Pseudomonas aeruginosa is the leading cause of nosocomial infection and is also one of the three bacterial pathogens in the WHO list of priority bacteria for developing new antibiotics against. A viable alternative to antibiotics is to use phages, which are bacterial viruses. Yet, the isolation of phages that efficiently kill their target bacteria has proven difficult. Using a combination of phages and antibiotics might increase treatment efficacy and prevent the development of resistance against phages and/or antibiotics, as evidenced by previous studies. Here, in vitro populations of a Pseudomonas aeruginosa strain isolated from a burn patient were treated with a single phage, a mixture of two phages (used simultaneously and sequentially), and the combination of phages and antibiotics (at sub-minimum inhibitory concentration (MIC) and MIC levels). In addition, we tested the stability of these phages at different temperatures, pH values, and in two burn ointments. Our results show that the two-phages-one-antibiotic combination had the highest killing efficiency against the P. aeruginosa strain. The phages tested showed low stability at high temperatures, acidic pH values, and in the two ointments. This work provides additional support for the potential of using combinations of phage–antibiotic cocktails at sub-MIC levels for the treatment of multidrug-resistant P. aeruginosa infections.     

In vitro and in vivo bactericidal activity of Vitex negundo leaf extract against diverse multidrug resistant enteric bacterial pathogens

ObjectiveTo investigate in vitro and in vivo antibacterial potentials of Vitex negundo (V. negundo) leaf extracts against diverse enteric pathogens.MethodsWater and methanol extracts of V. negundo leaves were evaluated against enteric bacterial pathogens by using standard disc diffusion, viable bacterial cell count methods, determination of minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC).ResultsMethanol extract of V. negundo leaves showed potent antibacterial activity (inhibition zone: 9.9–22.6 mm, MIC: 200–3200 μg/mL, MBC: 200–6400 μg/mL) against all the pathogenic enteric bacteria (Vibrio cholerae, Vibrio parahaemolyticus, Vibrio mimicus, Echerichia coli, Shigella spps., and Aeromonas spps) tested. Methanol extract of V. negundo leaves showed potent bactericidal activity both in vitro laboratory conditions (MBC, 200-400 μg/mL) and in the intestinal environment (Dose, 1-2 mg/mL) of infant mice against pathogenic Vibrio cholerae, the major causative agent of cholera. Furthermore, assays using the mice cholera model showed that V. negundo methanol extract can protect mice from Vibrio cholerae infection and significantly decrease the mortality rate (P<0.0001).ConclusionsFor the first time we showed that methanol extract of V. negundo leaves exhibited strong vibriocidal activity both in vitro and in vivo conditions. Therefore, it will be useful to identify and isolate the active compounds of this extract that could be a good alternative of antibiotics to treat cholera.     

Antibacterial activity of medicinal plant Cyclea peltata (Lam) Hooks & Thoms

ObjectiveTo investigate the antibacterial activity of Padathaali (Cyclea peltata) against three gram positive and eight gram negative bacterial strains.MethodsThe fresh whole plants were collected from Kerala, India. The dry crude nonpolar and polar extract of whole plant of C. peltata i. e. Petroleum ether, hexane, chloroform, ethyl acetate, acetone, methanol and aqueous extracts of five concentrations (1, 2, 5, 10 mg/ml) were used to investigate the antibacterial activity. NCCL standards were strictly followed to perform antibacterial disc susceptibility test using disc diffusion method.ResultsAll the extracts showed varying degree of inhibitory potential against all the tested bacteria. Methanol extract of plant had higher inhibitory action against Staphylococcus aureus, Streptococcus haemolyticus, Klebsiella pneumonia and Proteus vulgaris. Acetone extract of plant showed maximum inhibitory action against Klebsiella pneumonia and Streptococcus haemolyticus.ConclusionsThe present investigation showed the effectiveness of crude extract of this plant against tested bacterial strains. This study further suggests the use of whole plant extract in treating disease caused by tested microbial organisms.     

Antibacterial activity and characterization of secondary metabolites isolated from mangrove plant Avicennia officinalis

ObjectiveTo explore antibacterial activity and characterization of secondary metabolites isolated from mangrove plant Avicennia officinalis (A. officinalis).MethodsIn the present study the leaf extracts of A. officinalis were examined for its antibacterial potential using five different solvents against some reference strains of human pathogenic bacteria for the crude extract. Maximum activity was observed for ethyl acetate and hence different concentrations like 15 μL, 25 μL, and 50 μL of ethyl extracts was checked for its antibacterial activity. Partial purification of crude extract was carried by column chromatography and fractions were analyzed using gas chromatography-mass spectrometry (GC-MS) to identify compounds.ResultsThe crude ethyl acetate extracts of A. officinalis showed remarkable antibacterial activity with zones of inhibition of 13 mm against Eschericia coli (E. coli) and 11 mm against Staphylococcus aureus (S. aureus). Fraction 13 (ethyl acetate÷methanol= 8÷2) as the most potent one against with the minimal inhibitory concentration of 30 mm against E. coli and 25 mm against S. aureus. The GCMS resultsof active column fraction (F13) revealed that the active principals were a mixture of hydroxy-4 methoxybenzoic acid, diethyl phthalate, oleic acid.ConclusionsThe leaf extracts with proven antibacterial effects can clearly be directed towards cancer treatment as to inhibiting cancer cell growth. The limited number of test organisms owes to a constraint of resource. So, the effect of strong bursts of leaf extracts on human pathogenic bacteria should further be tested on a wide range of test organisms.     

Antibacterial activities of some Indian traditional plant extracts

ObjectiveTo evaluate the in vitro antibacterial activity of various solvent extracts of South Indian traditional medicinal plants Ocimum sanctum, Ocimum gratissimum, Aegle marmelos, and Adhatoda vasica leaves against clinical pathogens of human origin.MethodsThe antimicrobial activity of different solvents crude extract of four medicinal plants used in traditional Indian medicine was tested by disc diffusion method against five bacterial pathogens: Escherichia coli, Staphylococcus aureus, Salmonella typhi, Salmonella paratyphi and klebsiella pneumoniae.. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) was determined for evaluating the potential plant extract.ResultsThe antibacterial results showed methanol extracts (0.4 g/ml) of Ocimum gratissimum and Ocimum sanctum showed maximum zone of inhibition (30 mm and 25.5 mm, respectively) against Salmonella typhi. MIC was tested at various concentrations from 0.625 mg/ml to 0.039 mg/ml for all the plant extracts. At the lowest concentration (0.039mg/ml) tested, methanol extracts of Ocimum gratissimum showed higher MIC against Salmonella typhi and Salmonella paratyphi where as the methanolic extracts of Ocimum gratissimum showed potent activity against Staphylococcus aureus at 0.078 mg/ml. Methanol extract (0.4 g/ml) of Aegle marmelos showed significant inhibitory activity of 22.5mm and MIC value of 0.156.mg/ml against E. coli strain. The Klebsiella spp was the most resistant strain of all and various concentrations Adhatoda vasica extract showed less activity against the tested pathogens.ConclusionsThe present screening result demonstrated that the Indian traditional medicinal plants Ocimum sanctum, Ocimum gratissimum, Aegle marmelos methanol leaf extract has potent antibacterial activity and the studied plants may be new source for novel antibacterial compound discovery for treating drugs resistant human pathogens.     

Green synthesis of titanium dioxide nanoparticles using Psidium guajava extract and its antibacterial and antioxidant properties

Objective:To determine the efficacies of antibacterial and antioxidant activities of aqueous leaf extract of Psidium guajava mediated biosynthesis of titanium dioxide nanoparticles(TiO_2,NPs).Methods:Synthesized TiO_2 NPs were tested by disc diffusion method against against human pathogenic bacteria.The total antioxidant activity and phenolic content(Folin—Ciocalteau method) of synthesized TiO_2 NTs and aqueous plant extract were determined.The scavenging radicals were estimated hv DPPH method.The synthesized TiO_2 NPs were characterized by XRD,FTIR.FESEM and EDX,Results:FTIR spectra of synthesized TiO_2 NPs exhibited prominent peaks at 3410 cm~(-1)(alkynes),1 578 cm~(-1).1 451 cm~(-1)(alkanes),and 1 123 cm~(-1)(C-O absorption).The morphological characterization of synthesized TiO_2 NPs was analysed by FESEM which showed spherical shape and clusters with an average size of 32.58 nm.The maximum zone of inhibition was observed in the synthesized TiO_2 NPs(20 μg/mL) against Staphylococcus aureus(25 mm) and Escherichia coli(23 mm).The synthesized TiO_2 NPs showed more antibacterial activity than the standard antibiotic disk,tetracycline which drastically reduces the chances for the development of antibiotics resistance of bacterial species.The plant aqueous extract and synthesized TiO_2NPs were found to possess maximum antioxidant activity when compared with ascorbic acid.The content of phenolic compounds(mg/g) in Leaf aqueous extract and synthesized TiO_2 NPs were found to be 85.4 and 18.3 mgTA/g,respectively.Conclusions:Green synthesized TiO_2 NPs provides a promising approach can satisfy the requirement of large-scale industrial production hearing the advantage of low—cost,eco—friendly and reproducible.     

Bio-Synthesis of Aspergillus terreus Mediated Gold Nanoparticle: Antimicrobial,Antioxidant, Antifungal and In Vitro Cytotoxicity Studies

Gold nanoparticles (GNP) were bio-fabricated utilizing the methanolic extract of the endophytic isolate Aspergillus terreus. The biosynthesised gold nanoparticles (GNP023) were characterised using UV-visible spectroscopy (UV-Vis); transmission electron microscopy (TEM), Fourier-transform nfrared spectroscopy (FTIR) and X-ray diffraction (XRD) studies. The bio-fabricated GNP023 displayed a sharp SPR peak at 536 nm, were spherically shaped, and had an average size between 10–16 nm. The EDX profile confirmed the presence of gold (Au), and XRD analysis confirmed the crystalline nature of GNP023. The antimicrobial activity of GNP023 was investigated against several food-borne and phytopathogens, using in vitro antibacterial and antifungal assays. The maximum zone of inhibition was observed for S. aureus and V. cholera at 400 μg /mL, whereas inhibition in radial mycelial growth was observed against Fusarium oxysporum and Rhizoctonia solani at 52.5% and 65.46%, respectively, when challenged with GNP023 (200 μg/mL). Moreover, the gold nanoparticles displayed significant antioxidant activity against the ABTS radical, with an IC₅₀ of 38.61 µg/mL, and were non-toxic when tested against human kidney embryonic 293 (HEK293) cells. Thus, the current work supports the application of myco-synthesised gold nanoparticles as a versatile antimicrobial candidate against food-borne pathogens.     

Antibacterial activity of ethyl acetate and aqueous extracts of Mentha longifolia L. and hydroalcoholic extract of Zataria multiflora Boiss. plants against important human pathogens

ObjectiveTo determine the potential antibacterial activity of ethyl acetate and aqueous extracts from Mentha longifolia L. (M. longifolia) and hydroalcoholic extract of Zataria multiflora Boiss. (Z. multiflora) against important human pathogens.MethodsPseudomonas aeruginosa, Shigella dysenteriae, Klebsiella pneumoniae (K. pneumonia), Enterobacter cloacae, Salmonella typhi, Proteus mirabilis, Serratia marcescens, Bacillus cereus, Staphylococcus saprophyticus and Staphylococcus aureus were kinds of pathogenic bacteria to determine the antibacterial effect of aqueous and ethyl acetate extracts of M. longifolia and hydroalcoholic extract of Z. multiflora using broth microdiluation method.ResultsThe lowest minimum inhibitory concentration and minimum bactericidal concentration values for K. pneumonia and Pseudomonas aeruginosa (1.25 and 2.5 mg/mL) were observed by the hydroalcoholic extract of Z. multiflora and the lowest minimum inhibitory concentration and minimum bactericidal concentration values for K. pneumonia and Serratia marcescens (2.5 and 5 mg/mL) were observed by the aqueous extracts of M. longifolia.ConclusionsIn conclusion, it seems that Z. multiflora and M. longifolia extracts could inhibit the growth of all of the mentioned bacteria.     

Antibacterial activity of silver nanoparticles functionalized with amikacin applied against multidrug-resistant acinetobacter baumannii

BackgroundMultidrug-resistant bacteria are one of the world's biggest health problems; therefore, improving the spectrum of action of antibiotics could be necessary to reverse this situation. Amikacin and silver salts have well-known antimicrobial properties. However, both drugs lost their effectiveness against some bacteria, such as Acinetobacter baumannii. This work aims to develop a nanodrug from silver nanoparticles (AgNPs) functionalized with Amikacin against multidrug-resistant Acinetobacter baumannii.MethodsAgNPs were produced using the bottom-up methodology and functionalized with Amikacin modified by the carbodiimide-based chemistry, forming AgNPs@Amikacin. Susceptibility tests were performed using Amikacin-resistant Acinetobacter baumannii strains to assess the bacteriostatic and bactericidal potential of the developed nanodrug. The clinical strains were induced to form a biofilm, and biomass quantification and the metabolic activity were determined.ResultsThe AgNPs have a hydrodynamic diameter of the particles with a bimodal distribution, with a size of 37.84 nm. The FT-IR spectrum of AgNPs@Amikacin exhibits vibrational modes corresponding to Amikacin, confirming the conjugation to AgNPs. Susceptibility testing demonstrated a minimal inhibitory and bactericidal concentration of < 0.5 µg/mL. The AgNPs@Amikacin reduced the biofilm metabolic activity of Acinetobacter baumannii at rates ≥ 50%, characterized by the minimal biofilm inhibition concentrations.ConclusionsResults demonstrate a promising development of a new nanodrug with lower concentrations, less toxicity, and greater efficacy against multidrug-resistant Acinetobacter baumannii.     

Evaluation of antimicrobial study in in vitro application of Clerodendrum infortunatum Linn.

ObjectiveTo evaluate the antimicrobial potency of ethanol and chloroform extracts of root, leaf and stem of Clerodendrum infortunatum (Verbenaceae) and to explore a scientific data as this plant was randomly use in traditional medicine to cure common ailments such as intestinal disorder, diarrhea, tuberculosis and respiratory problems, etc.MethodsThe in vitro application was carried out by using disc diffusion, micro broth dilution and serial dilution techniques against clinically important life threatening organisms.ResultsAll the extracts showed significant inhibitory activity over the bacteria and fungus comparable to the standard drug tetracycline and fluconazole. The maximum average diameter zone of inhibition was recorded to bacterial strains against Bacillus megaterium, Salmonella typhi, Klebsiella pneumoniae and to fungi against Aspergillus niger and Candida albicans. The minimum inhibitory concentration values of ethanol leaf extract were determined 64 μg/mL to Bacillus megaterium, Salmonella typhi and Klebsiella pneumoniae; 128 μg/mL to Staphylococcus aureus, Streptococcus-β–haemolyticus and Escherichia coli.ConclusionsThe findings evidently appear promising antibacterial and antifungal properties of Clerodendrum infortunatum against antagonistic pathogens. Leaf possesses quite potent activity than root and stem specially leaf extract>root extract>stem extract. This study serves as basis for further research to lead compounds to be isolated so that it may be as a template for the implications of these results for bioactivity and drug discovery potential of herbal products.     

Larvicidal activity of green synthesized silver nanoparticles using bark aqueous extract of Ficus racemosa against Culex quinquefasciatus and Culex gelidus

ObjectiveTo investigate the larvicidal activity of synthesized silver nanoparticles (Ag NPs) utilizing aqueous bark extract of Ficus racemosa (F. racemosa) was tested against fourth instar larvae of filariasis vector, Culex quinquefasciatus (Cx. quinquefasciatus) and japanese encephalitis vectors, Culex gelidus (Cx. gelidus).MethodsThe synthesized Ag NPs was characterized by UV-vis spectrum, X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR). The larvicidal activities were assessed for 24 h against the larvae of Cx. quinquefasciatus and Cx. gelidus with varying concentrations of aqueous bark extract of F. racemosa and synthesized Ag NPs. LC₅₀ and r² values were calculated.ResultsThe maximum efficacy was observed in crude aqueous extract of F. racemosa against the larvae of Cx. quinquefasciatus and Cx. gelidus (LC₅₀=67.72 and 63.70 mg/L; r²=0.995 and 0.985) and the synthesized Ag NPs (LC₅₀=12.00 and 11.21 mg/L; r²=0.997 and 0.990), respectively. Synthesized Ag NPs showed the XRD peaks at 2 θ values of 27.61, 29.60, 35.48, 43.48 and 79.68 were identified as (210), (121), (220), (200) and (311) reflections, respectively. The FTIR spectra of Ag NPs exhibited prominent peaks at 3 425, 2 878, 1 627 and 1 382 in the region 500-3 000 cm^?1. The peaks correspond to the presence of a stretching vibration of (NH) C=O group. SEM analysis showed shape in cylindrical, uniform and rod with the average size of 250.60 nm.ConclusionsThe biosynthesis of silver nanoparticles using bark aqueous extract of F. racemosa and its larvicidal activity against the larvae of disease spreading vectors. The maximum larvicidal efficacy was observed in the synthesized Ag NPs.     

Antimicrobial PAA/PAH Electrospun Fiber Containing Green Synthesized Zinc Oxide Nanoparticles for Wound Healing

Wound infections are the main complication when treating skin wounds. This work reports a novel antimicrobial material using green synthesized zinc oxide nanoparticles (ZnONPs) incorporated in polymeric fibers for wound healing purposes. ZnONPs are a promising antimicrobial nanomaterial with high activity against a range of microorganisms, including drug-resistant bacteria. The electrospun fibers were obtained using polyacrylic acid (PAA) and polyallylamine hydrochloride (PAH) and were loaded with ZnONPs green synthesized from Ilex paraguariensis leaves with a spherical shape and ~18 nm diameter size. The fibers were produced using the electrospinning technique and SEM images showed a uniform morphology with a diameter of ~230 nm. EDS analysis proved a consistent dispersion of Zn in the fiber mat, however, particle agglomerates with varying sizes were observed. FTIR spectra confirmed the interaction of PAA carboxylic groups with the amine of PAH molecules. Although ZnONPs presented higher antimicrobial activity against S. aureus than E. coli, resazurin viability assay revealed that the PAA/PAH/ZnONPs composite successfully inhibited both bacteria strains growth. Photomicrographs support these results where bacteria clusters were observed only in the control samples. The PAA/PAH/ZnONPs composite developed presents antimicrobial activity and mimics the extracellular matrix morphology of skin tissue, showing potential for wound healing treatments.     

Fabrication of Gelatin-ZnO Nanofibers for Antibacterial Applications

In this study, GNF@ZnO composites (gelatin nanofibers (GNF) with zinc oxide (ZnO) nanoparticles (NPs)) as a novel antibacterial agent were obtained using a wet chemistry approach. The physicochemical characterization of ZnO nanoparticles (NPs) and GNF@ZnO composites, as well as the evaluation of their antibacterial activity toward Gram-positive (Staphyloccocus aureus and Bacillus pumilus) and Gram-negative (Escherichia coli and Pseudomonas fluorescens) bacteria were performed. ZnO NPs were synthesized using a facile sol-gel approach. Gelatin nanofibers (GNF) were obtained by an electrospinning technique. GNF@ZnO composites were obtained by adding previously produced GNF into a Zn²⁺ methanol solution during ZnO NPs synthesis. Crystal structure, phase, and elemental compositions, morphology, as well as photoluminescent properties of pristine ZnO NPs, pristine GNF, and GNF@ZnO composites were characterized using powder X-ray diffraction (XRD), FTIR analysis, transmission and scanning electron microscopies (TEM/SEM), and photoluminescence spectroscopy. SEM, EDX, as well as FTIR analyses, confirmed the adsorption of ZnO NPs on the GNF surface. The pristine ZnO NPs were highly crystalline and monodispersed with a size of approximately 7 nm and had a high surface area (83 m²/g). The thickness of the pristine gelatin nanofiber was around 1 µm. The antibacterial properties of GNF@ZnO composites were investigated by a disk diffusion assay on agar plates. Results show that both pristine ZnO NPs and their GNF-based composites have the strongest antibacterial properties against Pseudomonas fluorescence and Staphylococcus aureus, with the zone of inhibition above 10 mm. Right behind them is Escherichia coli with slightly less inhibition of bacterial growth. These properties of GNF@ZnO composites suggest their suitability for a range of antimicrobial uses, such as in the food industry or in biomedical applications.     

Antibacterial activity of crude ethanolic extract and solvent fractions of Ficus pseudopalma Blanco leaves

ObjectiveTo investigate the antimicrobial properties of Ficus pseudopalma (F. pseudopalma) leaf extracts.MethodsThe antibacterial properties of F. pseudopalma Blanco crude ethanolic leaf extract, and its solvent fractions chloroform (CF), ethylacetate (EF) and water fractions were evaluated through antibacterial agar disc diffusion method and the minimum inhibitory concentration (MIC) was determined. Five Gram-positive and five Gram-negative bacteria were used for the study.ResultsThe zone of inhibitions obtained from the antibacterial agar diffusion disc method showed that CF, and EF exhibited active (14-19 mm) antibacterial activity against Bacillus subtilis UST CMS 1011, and partially active (10-13 mm) antibacterial properties against both Staphylococcus aureus ATCC 25923 and Staphylococcus epidermidis ATCC 12228. Water exhibited no antibacterial properties against all microorgranisms tested. The MIC values observed for all Gram-positive bacteria tested were >5 mg/mL, except for Bacillus subtilis whose MIC value was 5 mg/mL for CF and EF fractions. All extracts exhibited no antibacterial activity against Gram-negative bacteria.ConclusionsFrom this study, it can be concluded that F. pseudopalma extracts may be a potential antibacterial agent against Gram-positive bacteria. The antibacterial property may be attributed to flavonoids and terpenoids present in the crude ethanolic extract, CF and EF.