Degree Of Antibacterial Activity Research Articles

Chemical analysis of phenolic compounds and determination of antioxidant, antimicrobial and cytotoxic activities of organic extracts of Pinus coulteri

New bioactive natural products, the phenolic composition and the biological activities of organic extracts from the needles of the Algerian Pinus coulteri were investigated. The analysis by HPLC-DAD of crude extract revealed the presence of 10 phenolic acids and nine flavonoids. In vitro anti-oxidant activities were performed using four different tests. The greatest antiradical activity was found in the ethyl acetate fraction (IC50 = 3.2 ± 0.3 µg/mL), whereas the diethyl ether fraction had the higher contents of total phenolics and flavonoids and exhibited a highest activity in reducing power and β-carotene–linoleic acid tests with EC50= 67.1 ± 0.4 μg/mL and 71.5 ± 0.2% of inhibition, respectively. Furthermore, a low to moderate antimicrobial activity according to all extracts was revealed against eight bacteria tested. The MIC value of chloroform fraction showed a strong degree of antibacterial activity (<0.09 mg/mL). The crude extract was found toxic with LC50 value of 15.2 μg/mL by brine shrimp toxicity assay. The needle extract of P. coulteri is rich in valuable biologically active compounds and could represent a new resource of anti-oxidant agents for the treatment of diseases.
 Video Clip of Methodology:
 Disc diffusion test: 6 min 41 sec Click to watch

Biological and physico-chemical properties of new root canal sealers.

BackgroundThe purpose of the present study was to compare the biological and the physico-chemical properties of bioceramic-based root canal sealers, calcium hydroxide-based, MTA-based and epoxy resin-based root canal sealers.Material and MethodsTwo bioceramic-based sealers, one calcium hydroxide-based sealer, one MTA-based sealer and two epoxy resin-based sealers were tested.ResultsEasySeal and MTA Fillapex showed severe citotoxic activity, AH Plus and SealapexTM moderate cytotoxicity, BioRoot™ RCS and TotalFill BC Sealer were both cytocompatible. Except for TotalFill BC Sealer, all root canal sealers caused inhibition zones when tested with E. faecalis. The highest inhibition zone was observed for EasySeal, followed by AH Plus. BioRoot™ RCS, SealapexTM and MTA Fillapex showed the lowest inhibition zone. All the tested materials showed different degree of antibacterial activity by using direct contact test (DCT). The highest values were observed for BioRoot™ RCS, TotalFill BC Sealer and EasySeal, followed by MTA Fillapex and SealapexTM. Except for BioRoot RCS and TotalFill BC Sealer, all the root canal sealers fulfilled the requirements of the ISO 6876 standard, demonstrating a weight loss less than 3%. Bioroot RCS, TotalFill BC Sealer and SealapexTM exhibited high alkaline pH with an increase both for BioRoot™ RCS and TotalFill BC Sealer after 24 hours.ConclusionsThe new bioceramic-based sealers showed acceptable physico-chemical properties, but BioRoot™ RCS and TotalFill BC Sealer seems to be too soluble, not respecting ISO 6876 requirements. Key words:Antibacterial activity, cytoxicity, pH, root canal sealers, solubility.

In-Vitro Antibacterial Activity of Plantago Lanceolata Against Some Selected Standard Pathogenic Bacterial

The leaves of Plantago lanceolata have been used for centuries to treat diseases. Currently there is an increasing incidence of multiple antibiotic resistances in microorganisms which is a major threat. Widespread overuse of antibiotics is one led to increasing clinical resistance of previously sensitive microorganisms and the emergence of previously uncommon infections. Thus all these calls for an urgent need to search new, effective and safe anti-bacterial agents. The objective of this study was to determine antibacterial potentials of extracts of P. lanceolata against standard pathogens bacteria. Active antibacterial compounds were extracted using three solvents. The antibacterial sensitivity activities of crude extracts were determined using agar well diffusion assay. MIC and MBC of each crude extracts were also determined using broth dilution method. The test showed various degrees of antibacterial activity towards each standard pathogenic microorganism with mean zone of inhibition ranges up to 18±2mm against S. typhi. The plant extract was showed as low 3±1mm to high 18±2mm diameter inhibition zone. Chloroform extract have the least inhibition zone while the ethanol have highest inhibition zone. The extract value of MIC was showed at the ranges of 12.5mg to 50mg while the MBC were showed at the range of 25mg to 50mg. The result of this study showed that leaves of P. lanceolata have considerable antibacterial potential. The claimed efficacy could be attributable to antibacterial activity of its components but its mode of action is unclear.

CALLUS INDUCTION, PHYTOCHEMICAL STUDIES AND ANTIBACTERIAL ACTIVITY OF DECALEPIS ARAYALPATHRA (JOSEPH AND CHANDRAS) VENTER

Objective: The aim of the present study was designed for the induction of callus from leaf explants of Decalepis arayalpathra (D. arayalpathra) and to analyse their phytochemical constituents and antibacterial activity.Methods: The explants were cultured on Murashige and Skoog (MS) medium supplemented with different concentration of 2, 4-dichlorophenoxyacetic acid (2, 4-D) and later subcultured to the combination of 6-benzylaminopurine (BAP) and 1-naphthaleneacetic acid (NAA). The phytochemical constituents were analysed in the different solvent extracts using standard methods. Antibacterial activity of the different solvent extracts was carried out using agar well diffusion method against reference standards. Results: Callus induction was observed on MS medium supplemented with different concentration and combination of auxins and cytokinins. Maximum callus induction was noticed on media supplemented with 2, 4-D (2 mg/l) and BAP (1 mg/l)+NAA (0.5 mg/l) respectively. The phytochemical screening revealed the presence of alkaloids, flavonoids, phenols, tannins, steroids and terpenoids, glycosides, coumarins and quinone etc. All the solvent extracts showed varying degree of antibacterial activities against the bacterial strains (Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas fluorescence and Staphylococcus aureus). The maximum antibacterial activity of leaf was observed in aqueous (Klebsiella pneumoniae, 19.00±1.00) and methanolic extract (Klebsiella pneumoniae, 18.33±1.15). Whereas petroleum ether extract of the callus showed maximum inhibition (Bacillus subtilis, 17.00±1.00) compare to other extracts.Conclusion: The study revealed the presence of secondary metabolites in the leaf and callus extracts of D. arayalpathra. The methanolic extracts possess higher antibacterial activity compared to other solvent extracts. However, further studies have to be carried out for the isolation and identification of antimicrobial compounds against pathogens.

A comparative study of the physicochemical properties and antimicrobial qualities of Abuad moringa soap with conventional medicated soaps

The study was aimed at assessing the physicochemical properties and antimicrobial qualities of 'ABUAD moringa soap', a herbal soap produced with Moringa oleifera leaf by 'ABUAD Farm', Afe Babalola University, Ado Ekiti, Nigeria. The physicochemical properties and antimicrobial qualities of ABUAD moringa soap on some selected bacteria and fungi were evaluated and compared with those of some conventional medicated and herbal soaps commonly used in Nigeria, such as Dettol, Tetmosol, Tura, Septol, Delta and Dudu Osun (herbal), as well as Lux, which serves as a control soap. The results of the physicochemical analyses revealed that all the soaps fall within the pH range of 8.83 and 9.83. All the soaps possess low values of free caustic alkali and detectable free fatty acid, as well as moderate values of total fatty matter. In-vitro antibacterial and antifungal activities of the soaps were investigated against microbial agents commonly found in association with skin infections, using the well-agar diffusion technique. The bacteria tested were Staphylococcus aureus ATCC 25923 and Proteus mirabilis (ATCC 12453), as well as four clinical isolates namely, Escherichia coli, Leutococcus sanguinis, Corynebacterium accolens and Burkholderia cepacia. The fungi were Candida albicans ATCC 10231, Malassezia furfur ATCC 44349, and Cryptococcus neoformans ATCC 23645. All the soaps, with exeption of lux, produced varied degrees of antibacterial activities, but ABUAD Moringa soap and Dudu Osun indicated superior effectiveness against the bacteria tested. Antifugal activities were produced by ABUAD moringa and Dudu Osun soaps only, on the fungi tested. ABUAD Moringa produced significantly higher antifungal activities on Malassezia furfur ATCC 44349 and Candida albicans ATCC 10231 than Dudu Osun, but no significant difference was observed between the two soaps on their activities against Cryptococcus neoformans ATCC 23645. The study showed that ABUAD Moringa soap possesses high therapeutic potentials against agents of bacterial and fungal skin infections.

A comparison of the antibacterial activity of some African black soaps and medicated soaps commonly used for the treatment of bacteria-infected wound

Background: Black soap is a medicinal product that could be harnessed for economic purpose if properly packaged, and misconception about its traditional use by herbalists is thrown overboard.Aims: To promote the relevance of these soaps for economic development, this study compared the antibacterial activity of black soaps with medicated soaps widely used against bacterial infections.Methods: The antibacterial activities of these soap samples were determined by agar diffusion and macrobroth dilution methods.Results: In this study, the statistical analysis of the inhibition zones showed that black soaps were significantly (p < 0.05) more active than medicated soaps used against the test bacterial isolates. The black soaps inhibited and killed the isolates better than the medicated soaps at the different concentrations used. The minimum inhibitory concentration for Klebsiella pneumoniae and Enterococcus faecalis ranged between 0.125 mg/mL and 2 mg/mL, Staphylococcus aureus (0.25–4) mg/mL, Escherichia coli (0.125–4) mg/mL and Pseudomonas aeruginosa (1–4) mg/mL. The result showed that K. pneumoniae and E. faecalis were the most susceptible, followed by E. faecalis > E. coli > S. aureus > P. aeruginosa.Conclusion: As a valuable medicinal output derivable from organic waste product that could be converted to wealth, African black soap production, utilisation and commercialisation have tremendous economic potentials. These soaps showed significant antibacterial activity greater than those of the medicated soaps. Hence, their use could be a better option in place of commercially available medicated and antiseptic soaps because of the degree of antibacterial activities they exhibited.

Total synthesis and biological evaluation of spirotryprostatin A analogs.

Based on the spirotryprostatin A structure, a series of compounds belonging to spiro-indolyl diketopiperazine structural class were designed and synthesized, which embody an oxindole with an all-carbon quaternary stereocenter. The total synthesis can efficiently be accessed in a seven-step reaction sequence with 18-28% overall yield from commercially available materials, and a highly enantioselective 1,3-dipolar cycloaddition, N-acylation of the resulting stereochemically complex spiro[pyrrolidin-3,3'-oxindole]s core with Fmoc-L-pro-Cl and spontaneous ring closure upon N-deprotection were obtained. The synthesized compounds 13a-e and 15a-e were evaluated for their antibacterial activities. The result showed that compounds 13b and 15b were active only against Gram-positive bacteria, and selective antibacterial activity was exhibited by compounds 13d and 13e against Streptococcus lactis. Further, all the remaining compounds showed a certain degree of antibacterial activity. In addition, the structure-activity relationship is also discussed.

Multifunctional and biomimetic fish collagen/bioactive glass nanofibers: fabrication, antibacterial activity and inducing skin regeneration in vitro and in vivo.

The development of skin wound dressings with excellent properties has always been an important challenge in the field of biomedicine. In this study, biomimetic electrospun fish collagen/bioactive glass (Col/BG) nanofibers were prepared. Their structure, tensile strength, antibacterial activity and biological effects on human keratinocytes, human dermal fibroblasts and human vascular endothelial cells were investigated. Furthermore, the Sprague Dawley rat skin defect model was used to validate their effect on wound healing. The results showed that compared with pure fish collagen nanofibers, the tensile strength of the Col/BG nanofibers increased to 21.87±0.21 Mpa, with a certain degree of antibacterial activity against Staphylococcus aureus. It was also found that the Col/BG nanofibers promoted the adhesion, proliferation and migration of human keratinocytes. Col/BG nanofibers induced the secretion of type one collagen and vascular endothelial growth factor by human dermal fibroblasts, which further stimulated the proliferation of human vascular endothelial cells. Animal experimentation indicated that the Col/BG nanofibers could accelerate rat skin wound healing. This study developed a type of multifunctional and biomimetic fish Col/BG nanofibers, which had the ability to induce skin regeneration with adequate tensile strength and antibacterial activity. The Col/BG nanofibers are also easily available and inexpensive, providing the possibility for using as a functional skin wound dressing.

Tea polyphenols inhibit the growth and virulence properties of Fusobacterium nucleatum

Fusobacterium nucleatum plays a key role in creating the pathogenic subgingival biofilm that initiates destructive periodontitis. It is also a common resident of the human gastrointestinal tract and has been associated with inflammatory bowel disease. The aim of the present study was to investigate the effects of green and black tea extracts as well as two of their bioactive components, EGCG and theaflavins, on the growth and virulence properties of F. nucleatum. The tea extracts and components displayed various degrees of antibacterial activity that may involve damage to the bacterial cell membrane and the chelation of iron. They also prevented biofilm formation by F. nucleatum at concentrations that did not interfere with bacterial growth. In addition, the treatment of a pre-formed F. nucleatum biofilm with the green tea extract and EGCG caused a time-dependent decrease in biofilm viability. The green and black tea extracts, EGCG, and theaflavins decreased the adherence of F. nucleatum to oral epithelial cells and matrix proteins. Moreover, these tea components also attenuated F. nucleatum-mediated hemolysis and hydrogen sulfide production, two other virulence factors expressed by this bacterium. In summary, this study showed that tea polyphenols may be of interest for treating F. nucleatum-associated disorders.

ANTIBACTERIAL ACTIVITY OF THE MEDICINAL PLANT, ACALYPHA FRUTICOSA FORSSK.

The present study is to confirm the antibacterial efficacy of root extracts of the folklore medicinal plant species, Acalypha fruticosa by using three alcoholic solvents viz; petroleum ether, ethyl acetate and methanol were tested against ten human pathogenic bacteria viz., Pseudomonas aeruginosa, P. stutzeri,Escherichia coli, Micrococcus sp., Lactobacillus sp., Servatia sp., Moraxetta sp., Bacillus subtilis, B. thuriengensis, and Klebsiella pneumoniae for assessing the antibacterial properties by adapting disc diffusion method. The results of the study revealed that all extracts showed varied degree of antibacterial activity against the tested pathogens. However, the methanol extract exhibited higher inhibition zone (21.83 mm) against the bacterium, Bacillus subtilis. This result supports the therapeutic importance of the species, Acalypha fruticosa in curing infectious diseases and encourages the extensive use of this species in health carepractices.

Antibacterial and cytotoxic cytochalasins from the endophytic fungus Phomopsis sp. harbored in Garcinia kola (Heckel) nut

BackgroundThe continuous emergence of multidrug-resistant (MDR) bacteria drastically reduced the efficacy of our antibiotic armory and consequently, increased the frequency of therapeutic failure. The search for bioactive constituents from endophytic fungi against MDR bacteria became a necessity for alternative and promising strategies, and for the development of novel therapeutic solutions. We report here the isolation and structure elucidation of antibacterial and cytotoxic compounds from Phomopsis sp., an endophytic fungus associated with Garcinia kola nuts.MethodsThe fungus Phomopsis sp. was isolated from the nut of Garcinia kola. The crude extract was prepared from mycelium of Phomopsis sp. by maceration in ethyl acetate and sequentially fractionated by column chromatography. The structures of isolated compounds were elucidated on the basis of spectral studies and comparison with published data. The isolated compounds were evaluated for their antibacterial and anticancer properties by broth microdilution and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide methods respectively. The samples were also tested spectrophotometrically for their hemolytic properties against human red blood cells.ResultsThe fractionation of the crude extract afforded three known cytochalasins including 18-metoxycytochalasin J (1), cytochalasins H (2) and J (3) together with alternariol (4). The cytochalasin compounds showed different degrees of antibacterial activities against the tested bacterial pathogens. Shigella flexneri was the most sensitive microorganism while Vibrio cholerae SG24 and Vibrio cholerae PC2 were the most resistant. Ampicillin did not show any antibacterial activity against Vibrio cholerae NB2, Vibrio cholerae PC2 and Shigella flexneri at concentrations up to 512 μg/mL, but interestingly, these multi-drug resistant bacterial strains were sensitive to the cytochalasin metabolites. These compounds also showed significant cytotoxic properties against human cancer cells (LC50 = 3.66–35.69 μg/mL) with low toxicity to normal non-cancer cells.ConclusionThe three cytochalasin compounds isolated from the Phomopsis sp. crude extract could be a clinically useful alternative for the treatment of cervical cancer and severe infections caused by MDR Shigella and Vibrio cholerae.

Screening a Phage Display Library for Two Novel OmpU-Binding Peptides with Adhesion Antagonistic Activity against Vibrio mimicus.

Vibrio mimicus is a pathogen that causes ascites disease in fish. We have previously demonstrated that the outer membrane protein U (OmpU) is an important adhesin in V. mimicus. Here eight specific OmpU-binding phage clones, which presented three different OmpU-binding peptides (designated P1, P2, P3), were screened from a commercially available phage displayed 12-mer peptide library using rOmpU protein as target. Then, synthetic OmpU-binding peptides were measured for their adhesion antagonistic activity and binding affinity via adhesion inhibition test and non-competitive ELISA, respectively. The results showed that after co-incubated with the mixture of rOmpU and P3, visible green fluorescence could be observed on the epithelioma papulosum cyprinidi (EPC) cells surface; while the EPC cells co-incubated with the mixture of rOmpU and P1/P2 exhibited little green fluorescence. The average adhesion number of V. mimicus 04–14 isolate before and after treatment with peptide was 21.4 ± 1.5, 20.8 ± 0.8 (irrelevant peptide), 20.2 ± 0.5 (P3), 5.1 ± 0.7 (P1) and 3.4 ± 0.8 (P2), respectively. There was a significant decrease in the adhesive level of 04–14 isolate treated with P1/ P2 compared to the untreated isolate (p<0.01). The affinity constants of P1 and P2 were (6.17 ± 0.19) × 108 L/mol and (1.24 ± 0.56) × 109 L/mol, respectively. Furthermore, protective effects of P1 and P2 on grass carps challenged with V. mimicus were preliminary detected. It was found there was delayed death of fish in the groups treated with P1/P2, and the survival rate of challenged fish improved with the increase of the dose of adhesion antagonistic peptide. Taken together, two novel OmpU-binding peptides, which possessed adhesion antagonistic activity, high affinity and a certain degree of antibacterial activity against V. mimicus, were screened and identified.

Controle de Qualidade de Amostras Comerciais de Schinus terebinthifolius Raddi (Aroeira) Adquiridas em Mercados Públicos da Cidade de São Luís-MA

The phytotherapy has been becoming an important alternative to terapeutic all over the world. Thereby, several plants have been commercialized at public markets and fairs in many countries. Schinus terebinthifolius Raddi is a species popularly known as aroeira in Brazil and is considered one of the most consumed plants in our country due to its medicinal properties. This study aimed to evaluate the quality of commercial samples of aroeira, purchased at public markets in Sao Luis-MA, Brazil. Twelve samples of barks from S. terebinthifolius were purchased and analyzed. Furthermore barks from an identified specimen of this species were used as reference sample. To assure the authentication, the commercial samples were analyzed by morphological and anatomical features, phytochemical profile, moisture content and antibacterial activity and then the results from these samples were compared to reference sample features. Among the 12 samples, the half showed different morphological features from the reference sample. According to the microscopic study, just five were authenticated as S. terebinthifolius . The phytochemistry evaluation showed different chemistry profiles of commercial samples, mainly regarding to tanins and saponins amount. Five samples were reproved by moisture determination. All samples showed some degree of antibacterial activity against S taphylococcus aureus , however, only six were active against Escherichia coli . Although the importance of phytoterapy has grew, these results show the poor quality of this drug and also show the concerned about the quality of the herbal products commercialized worldwide to assure the consumer safety. Keywords: Authenticity; quality control; Schinus terebinthifolius Raddi.

Impact of floral sources and processing on the antimicrobial activities of different unifloral honeys

ObjectiveTo study in vitro antibacterial activity and physicochemical properties of three unifloral honeys (citrus, clover and cotton honeys), and to study the impacts of storage, dilution with water (33%, w/v) and autoclaving (121 °C for 15 min) on honeys characteristics. MethodsHoney samples from monofloral sources including citrus (Citrus spp.), Egyptian clover (Trifolium alexandrium) and cotton (Gossypium vitifolium) were obtained during three successive seasons (2010–2012). Physicochemical properties and antimicrobial activities of different honey samples were studies. ResultsIn honey samples stored for 12 or 24 month, colour, hydroxymethyl furfural and acidity increased, while refractive index, water activity, total soluble solids, electrical conductivity and pH remained relatively unaffected, but H2O2 values decreased. Types of honey exhibited various degrees of antibacterial activity against different indicator bacteria, wherein the highest antibacterial activity was recorded for clover honey followed by citrus and cotton honeys, respectively. Different species of bacteria were differed in their sensitivity to honey, wherein Salmonella enteritidis was the most sensitive followed by Staphylococcus aureus, Listeria monocytogenes and Escherichia coli, respectively. Storage up to 24 months at room temperature slightly reduced the antibacterial activity. The reduction levels were about 2.6% and 4.6% after 12 and 24 months, respectively. Diluting honeys with water increased the antibacterial activity by ca. 8.3%, while autoclaving decreased the antibacterial activity by ca. 13.5%. The relative contribution of the peroxide and non-peroxide components in the total antibacterial activity of fresh honeys was investigated. The antibacterial activity of honeys was mainly attributed to non-peroxide antibacterial agents, wherein their contribution was ca. 88%, while the contribution of H2O2 was only 12%. The contribution of the thermostable antibacterial components in honey was ca. 86.8%. The antibacterial activity of the fresh clover honey was compared with the effect of 16 antibiotics on indicator bacteria. Clover honey exhibited antibacterial activity comparable to that exhibited by the tested antibiotics. Moreover, antibacterial activity of water diluted fresh clover honey was higher compared to some of tested antibiotics. Clover honey appeared to deserve further investigations, since it may prove to be a promise therapeutic honey. ConclusionsHoney samples tested in this study exhibited antibacterial activity against tested pathogenic bacteria, and this activity was mainly due to non-peroxide antibacterial factors. Clover honey appeared to deserve further investigations, since it may prove to be a promising therapeutic honey.

Antibacterial activities of selected edible plants extracts against multidrug-resistant Gram-negative bacteria

BackgroundIn response to the propagation of bacteria resistant to many antibiotics also called multi-drug resistant (MDR) bacteria, the discovery of new and more efficient antibacterial agents is primordial. The present study was aimed at evaluating the antibacterial activities of seven Cameroonian dietary plants (Adansonia digitata, Aframomum alboviolaceum, Aframomum polyanthum, Anonidium. mannii, Hibiscus sabdarifa, Ocimum gratissimum and Tamarindus indica).MethodsThe phytochemical screening of the studied extracts was performed using described methods whilst the liquid broth micro dilution was used for all antimicrobial assays against 27 Gram-negative bacteria.ResultsThe results of the phytochemical tests indicate that all tested extracts contained phenols and triterpenes, other classes of chemicals being selectively present. The studied extracts displayed various degrees of antibacterial activities. The extracts of A. digitata, H. sabdarifa, A. polyanthum, A. alboviolaceum and O. gratissimum showed the best spectra of activity, their inhibitory effects being recorded against 81.48%, 66.66%, 62.96%, 55.55%, and 55.55% of the 27 tested bacteria respectively. The extract of A. polyanthum was very active against E. aerogenes EA294 with the lowest recorded minimal inhibitory concentration (MIC) of 32 μg/ml.ConclusionThe results of the present work provide useful baseline information for the potential use of the studied edible plants in the fight against both sensitive and MDR phenotypes.

ANTIBACTERIAL ACTIVITY OF SELECTIVELY OXIDIZED LYOCELL FIBERS

The purpose of this research was to study antibacterial activity of selectively oxidized lyocell fibers with incorporated silver particles against gram (+) and gram (-) pathogens. Antibacterial properties were accomplished by incorporation of silver ions into modified lyocell fibers by chemisorption from aqueous silver nitrate solution. In order to improve sorption properties of lyocell fibers, the selective TEMPO-mediated oxidation, i.e. oxidation with sodium hypochlorite and catalytic amount of sodium bromide and 2,2´,6,6´-tetramethylpiperidine-1-oxy radical (TEMPO), was applied. The influence of oxidation conditions оn the amount of sorbed silver, and thus on the degree of antibacterial activity was determined. It was found that the maximum amount of sorbed silver was 0.996 mmol/g cell. The antibacterial activity of the TEMPO-oxidized lyocell fibers with silver particles was confirmed in vitro against two strains: Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922). The silver-loaded TEMPO-oxidized lyocell fibers showed better antimicrobial activity against strain Staphylococcus aureus.

Use of Natural Products as Green Reducing Agents To Fabricate Highly Effective Nanodisinfectants

Disinfection of water using nanoparticles (NPs) can be achieved through selection of either metals (M) or transition metal oxides (TMO). In this research, 64 formulations of silver-titania nanocomposites (Ag/TiO2) were prepared via a feasible wet-chemistry technique using different natural products as reducing agents. Four selected products successfully reduced Ag(+) ions to Ag, allowing Ag/TiO2 composite to efficiently inactivate microbes found in the activated sludge. The degree of antibacterial activity was measured using zone of inhibition, which indicated all formulations inactivated the bacteria with high potency (0.01 I/6 h). The results from this study and comparison of literature values collectively suggest that light roasted coffee acted as one of the best natural reducing agents due to its low antioxidant index (LAI). Our selection framework also suggested any M/TMO with an oxygen reduction potentials (ORP) range of -0.41 to +1.23 V and any natural product with a LAI (<0.5) would be suitable as a reducing agent. Collectively, the high ORP and low AI provide effective disinfection of water-borne microbes.

ANTIBACTERIAL ACTIVITY OF SELECTIVELY OXIDIZED LYOCELL FIBERS

The purpose of this research was to study antibacterial activity of selectively oxidized lyocell fibers with incorporated silver particles against gram (+) and gram (-) pathogens. Antibacterial properties were accomplished by incorporation of silver ions into modified lyocell fibers by chemisorption from aqueous silver nitrate solution. In order to improve sorption properties of lyocell fibers, the selective TEMPO-mediated oxidation, i.e. oxidation with sodium hypochlorite and catalytic amount of sodium bromide and 2,2´,6,6´-tetramethylpiperidine-1-oxy radical (TEMPO), was applied. The influence of oxidation conditions оn the amount of sorbed silver, and thus on the degree of antibacterial activity was determined. It was found that the maximum amount of sorbed silver was 0.996 mmol/g cell. The antibacterial activity of the TEMPO-oxidized lyocell fibers with silver particles was confirmed in vitro against two strains: Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922). The silver-loaded TEMPO-oxidized lyocell fibers showed better antimicrobial activity against strain Staphylococcus aureus.

Antibacterial and Antimycobacterial Lignans and Flavonoids from Larrea tridentata

Three lignans and four flavonoids were isolated and characterized from Larrea tridentata and compounds were tested against 16 bacterial species/strains. Results showed that: dihydroguaiaretic acid (1) had activity towards methicillin resistant (MR) Staphylococcus aureus (minimum inhibitory concentration (MIC) 50 µg/mL) and multidrug-resistant (MDR) strains of Mycobacterium tuberculosis (MIC 12.5-50 µg/mL); 4-epi-larreatricin (2) was active against Enterobacter cloacae (MIC 12.5 µg/mL), as well as sensitive (MIC 50 µg/mL) and MDR strains of M. tuberculosis (MIC 25 µg/mL). 3'-Demethoxy-6-O-demethylisoguaiacin (3) displayed activity against sensitive and resistant S. aureus (MIC 25 µg/mL), Enterococcus faecalis (MIC 12.5 µg/mL), Escherichia coli (MIC 50 µg/mL), E. cloacae (MIC 12.5 µg/mL) and MDR strains of M. tuberculosis (MIC 12.5 µg/mL). 5,4'-Dihydroxy-3,7,8,3'-tetramethoxyflavone (4) and 5,4'-dihydroxy-3,7,8-trimethoxyflavone (5) were active against M. tuberculosis MDR strains having MIC values of 25 and 25-50 µg/mL, respectively, while 5,4'-dihydroxy-7-methoxyflavone (6) was active against S. aureus (MIC 50 µg/mL) and E. faecalis (MIC 50 µg/mL). We concluded that lignan 3 is the main compound responsible for the antibacterial activity of L. tridentata. Lignans 1 and 2 as well as flavonoid 6 contribute with some degree of antibacterial activity. On the other hand, compounds 1, 2, 3, 4 and 5 contributed to the antimycobacterial activity found in L. tridentata.

Preliminary Phytochemical, UV-VIS, HPLC and Anti-bacterial Studies on Gracilaria corticata J. Ag

ObjectiveThe present study aimed to investigate the preliminary phytochemical analysis and UV-VIS, HPTC profiling and the antibacterial activity of Gracilaria corticata J. Ag extracts against the Gram positive and Gram negative bacteria. MethodsPreliminary phytochemical screening was carried out by Harborne method. The G. corticata extracts were tested against bacteria by the agar disc diffusion method. ResultsThe results of the presence study showed the presence of alkaloids, steroids, phenolic groups, saponins, tannin, flavonoids, terpenoids, glycosides and sugars. Proteins, xantoproteins, coumarins and catechin did not show any positive result for their presence in any of the six extracts of Gracilaria corticata tested. The result of the present study revealed the various behavior character of Gracilaria corticata crude drug. The UV-VIS spectrum profile of Gracilaria corticata methanolic, petroleum ether, benzene and aqueous extracts profiles were recorded. The HPLC profile of Gracilaria corticata petroleum ether benzene and aqueous extracts were tabulated. The maximum (9/12 bacterial pathogens) degree of antibacterial activity was observed in isopropanol soxhlet extracts followed by isopropanol cold extracts (7/12 bacterial pathogens). ConclusionThe results of the present study showed that G. corticata may be rich sources of phytoconstituents which can be isolated and further screened for different kinds of biological activities, depending on their reported therapeutic uses.