Degree Of Antibacterial Activity Research Articles

A 3D-printed PLGA/HA composite scaffold modified with fusion peptides to enhance its antibacterial, osteogenic and angiogenic properties in bone defect repair

Scaffold materials, seed cells and growth factors are referred to as the three elements of bone tissue engineering (BTE). However, the physical properties and biocompatibility of these scaffolds and the safety and cost of their growth factors limit their clinical application. Therefore, it is critical to develop a novel scaffold modified with efficient growth factors that meets the requirements of BTE. Herein, 3D-printed poly (lactic-co-glycolic acid)/hydroxyapatite (PLGA/HA) composite scaffolds modified with new fusion peptides, which can effectively promote the regeneration and repair of bone defects, were developed. 3D-printed PLGA/HA composite scaffolds with appropriate HA contents were prepared and had appropriate mechanical properties. In addition, the surface of the 3D-printed PLGA/HA composite scaffold was modified with new fusion peptides to provide osteogenic, antimicrobial, and angiogenesis-promoting effects. In vitro experiments showed that the fusion peptide-modified scaffolds had good biocompatibility and a certain degree of antibacterial activity. Moreover, the fusion peptide-modified scaffolds significantly improved the migration ability of BMSCs and Ea.hy926 cells, promoted the expression of osteogenesis-related factors (BMP2, RUNX2, ALP, OPN) in BMSCs, and promoted the expression of angiogenesis-related factors (VEGF and HIF-1α) in Ea.hy926 cells. In vivo experiments showed that the fusion peptide-modified scaffolds had good osteogenic ability. This study reveals considerable application potential for bone defect repair and provides a new option of scaffold material for BTE.

Development of ionic liquid-capped carbon dots derived from Tecoma stans (L.) Juss. ex Kunth: Combatting bacterial pathogens in diabetic foot ulcer pus swabs, targeting both standard and multi-drug resistant strains

Bacterial infection is rapidly growing and is a severe danger to global welfare worldwide. Consequently, there is a growing demand for novel antibacterial medications. As an outcome, the evaluation of antibacterial assets of carbon dots (CDs) including a variety of ionic liquids (ILs) were employed to reside advance notice of the structure tunability of ILs along with abundant surface functional group of designed amine-modified CDs, have recently sparked a lot of interest. In this study for the first time, highly efficient ionic-liquid decorated CDs were synthesized to assess the impact of capped-ionic liquid on the degree of antibacterial activity. Fluorescent amine-modified CDs (CDs-NH2) were obtained from the Tecoma stans (yellow elder flower) extract by a single-step carbonization method in presence of ethylenediamine, and then capped with ionic liquids; 3-(carboxymethyl)-1-methyl-1-H-imidazol-3-ium bromide (ILIM) and 3-(carboxymethyl)-1-methyl-1-H-benzo[d]imidazole-3-ium bromide (ILBIM) by a simple carbodiimide chemistry. In-vitro antibacterial activity of CDs-NH2, ILIM@CDs and ILBIM@CDs were evaluated against common pathogens, Escherichia coli (E. coli) as Gram(-ive) bacteria and Staphylococcus aureus (S. aureus) as Gram(+ive) bacteria as well as against clinical multi-drug resistant strain obtained from pus swab of diabetic foot ulcer, by microdilution method as well as well-diffusion method. The results showed that functional ILs-capped CDs have enhanced antibacterial activity against standard (E. coli, S. aureus) and clinical resistant bacterial strains, with minimal inhibitory concentrations (MICs) values range from 0 to 64 μg/mL for standard E. coli/ S. aureus and 250 μg/mL for drug resistant clinical strains, respectively. Structure activity analysis and molecular docking studies revealed that the antibacterial activity of ILBIM@CDs/ILIM@CDs is particularly better compared to CDs-NH2 and ionic-liquids.

Diversity of Fungal Communities on Diseased and Healthy Cinnamomum burmannii Fruits and Antibacterial Activity of Secondary Metabolites.

The composition and structure of fungal communities on healthy and diseased fruits of Cinnamomum burmannii (Nees and Nees) Blume were characterized, with evaluation of the antibacterial activity of secondary metabolites from culturable fungi following the first identification of secondary metabolites in the fungus Medicopsis romeroi (Esf-14; GenBank accession number OK242756). These results are significant for understanding the functional variation in bioactivity in fungal communities and developing a broader range of bioactive resources. High-throughput sequencing results indicated that the fungal community in diseased fruit differed from that in healthy fruit at the phylum, class, order, or genus level, with significant differences in the species and relative abundance of the dominant flora. A total of 49 (healthy fruit) and 122 (diseased fruit) artificially cultivable endophytic fungi were isolated, and 41 different strains (11 from healthy fruit and 30 from diseased fruit) were successfully identified by morphological and molecular biological analyses, which were classified into 8 groups and 23 genera by phylogenetic tree analysis, with Pleosporales, Glomerellales, and Hypocreales being the dominant groups at the order level and Colletotrichum being the dominant group at the genus level. The results of the antibacterial assay demonstrated that the secondary metabolites of all strains had different degrees of antibacterial activity, while the secondary metabolites of endophytic fungi from diseased fruit were generally stronger than those of fungi from healthy fruit, with the active secondary metabolites dominated by small and moderately polar compounds. Combined analysis of fungal communities, phylogenetic tree analysis, and bioactivity analysis of culturable strains revealed strong antibacterial activity of both upregulated and downregulated flora in diseased fruit. Five compounds, including two new (5,6-dimethoxy-[1',1:4,1″-terphenyl]-2-ol [compound 1] and 5-(methoxycarbonyl)-2-methylbenzo[d][1,3]dioxole-2-carboxylic acid [compound 2]) and three known compounds (3,7-dihydroxy-1,9-dimethyldibenzofuran [compound 3], methyl 3-hydroxybenzoate [compound 4], and uracil [compound 5]), were isolated and identified for the first time from the endophytic fungus Medicopsis romeroi. In general, the diversity of fungal communities on diseased fruit was lower than that on healthy fruits, while the antibacterial activity of artificially cultured endophytic fungi on diseased fruits was generally stronger than that on healthy fruits, suggesting excellent promise for the development of secondary metabolites from active strains on diseased fruit as antibacterial agents. IMPORTANCE Powdery fruit disease is a notorious disease of Cinnamomum burmannii that causes severe loss in fruit production. Studies on the function of endophytic fungal communities in healthy plant tissues are not new, while little is known about the functional changes of fungal communities in disease-causing plant tissues. Our results demonstrate that fungal communities in diseased fruits differ from those in healthy fruits at the level of phylum, class, order, or genus, with significant differences in the species and relative abundance of dominant groups. Endophytic fungi in diseased fruits appeared to produce secondary metabolites with stronger antibacterial properties, although the community diversity was not as varied as that in healthy fruits. In addition, secondary metabolites of the Medicopsis romeroi strain from diseased fruits were identified for the first time. These results have important implications for understanding the functional variation of bioactivity in fungal communities and for developing a broader resource of bioactivity.

In vitro antibacterial effect of Argentine propolis extracts on Streptococcus mutans and Actinomyces viscosus

Aim: In the present study, the antibacterial activity of the Ethanol Extract of Propolis (EEP), collected from various regions (Mendoza, Santiago del Estero, and Corrientes) in Argentina, against Streptococcus mutans ATCC® 35668™ and Actinomyces viscosus ATCC® 15987™ (MicroBioLogics Inc., USA) was investigated. Methods: Identification of geographic and botanical origin was based on a reconnaissance survey. Phytochemical screening of propolis was carried out on ethanolic extracts using standard methods to identify the constituents (aluminum chloride colorimetric method, Folin-Ciocalteu colorimetric method, thin layer chromatography). The agar diffusion method (discs and wells) and serial dilution method (plates and tubes) were used to evaluate the antibacterial activity of EEP. Results: EEP exerted various degrees of antibacterial activity against S. mutans and A. viscosus, depending on the geographic area of collection. Phytochemical screening showed that the bioactive compounds correspond to phenolic compounds and flavones. EEP from Tunuyán (Mendoza), where the most abundant vegetation belongs to Populus sp., showed the highest content of phenolic compounds (220.92±2.01 mg/g) and flavonoids (30.39±0.25 mg/g). This sample showed the most profound antibacterial activity among the EEP tested. By the agar-well diffusion method, we found a high susceptibility with an inhibitory halo of 11.25 ± 4.68 mm and 10.90 ± 4.21 mm against S. mutans and A. viscosus, respectively. It also presented low Minimum Inhibitory Concentration and Minimum Bactericidal Concentration values against S. mutans (MIC 0.05 mg/mL - MBC 0.46 mg/mL) followed by A. viscosus (MIC 0.11 mg/mL - MBC 0.93 mg/mL). Conclusions: The combined results from all methods indicated that S. mutans is more susceptible to the effect of the Tunuyán EEP than A. viscosus.Uniterms: Propolis. Streptococcus mutans. Actinomyces viscosus. Microbial sensitivity tests.

Metabolites of endophytic fungus Nigrospora sphaerica S5 from Myoporum bontioides

The endophytic fungus Nigrospora sphaerica S5 derived from the semi-mangrove plant Myoporum bontioides was fermented. Its metabolites were purified by column chromatography. Nine compounds were obtained and identified as terezine P(1), 3-(1-hydroxyethyl)-4-methyl dihydrofuran-2(3H)-one(2), methylhydroheptelidate(3), hydroheptelidic acid(4), 5, 7-dimethoxy-4, 6-dimethylphthalide(5),(3R,4S)-(-)-4-hydroxymellein(6), pestalopyrone(7), indole-3-formaldehyde(8) and p-hydroxybenzaldehyde(9) by spectroscopic techniques. Terezine P(1) was a new alkaloid belonging to the terezine class with a pyrazine ring. Compounds 2-7 were lactones, of which 3 and 4 belonged to sesquiterpenes. Compounds 8 and 9 were indole alkaloids and phenols, respectively. Compounds 3-6 were purified from Nigrospora sp. for the first time. These compounds showed different degrees of antibacterial activity against Staphylococcus aureus, Escherichia coli of O6 serotype and E. coli of O78 serotype.

Evaluation of Antibacterial Activity and Acute Toxicity of Methanol Extracts of Artemisia absinthium, Datura stramonium, and Solanum anguivi.

BackgroundBacterial pathogens have evolved numerous defense mechanisms against commercial antimicrobial agents, and their resistance to most of the available antimicrobials is increasing. Medicinal plants are a potential source of antimicrobial agents during the spread and emergence of infectious disease caused by resistant microorganisms. The aim of this study was thus to investigate the antimicrobial activity and acute toxicity of 80% methanol extracts of leaves of Artemisia absinthium, seeds of Datura stramonium, and fruit of Solanum anguivi.Materials and MethodsThe 80% methanol extracts were prepared by cold maceration. Antimicrobial activity was evaluated against five bacterial species using agar-well diffusion at concentrations of 125, 250, and 500 mg/mL in the presence of positive and negative controls. Minimum inhibitory concentration was determined by broth dilution. The acute toxicity study was done following OECD guidelines.ResultsThe 80% methanol extract of the fruit of S. anguivi exhibited better activity against most of the bacterial strains, of which Salmonella enterica serovar Typhimurium was found to be the most susceptible, with minimum inhibitory concentration and minimum bactericidal concentration of 1.3 mg/mL and 1.95 mg/mL, respectively, while the seed extract of D. stramonium showed the least activity against most test organisms. The acute toxicity study showed that all three plants had an LD50 >2,000 mg/kg body weight, and were thus safe.ConclusionThe results of this study revealed that the methanol extracts of the three plants (A. absinthium, D. stramonium, and S. anguivi) had different degrees of antibacterial activity against the selected pathogenic bacteria and were safe at higher doses, thus being of great potential to be developed as antibacterial agents. The study also provided scientific evidence to support the continued traditional use of these medicinal plants by communities in different parts of Ethiopia to treat infectious diseases.

Chevalones H-M: Six New α-Pyrone Meroterpenoids from the Gorgonian Coral-Derived Fungus Aspergillus hiratsukae SCSIO 7S2001.

Six new α-pyrone meroterpenoid chevalones H–M (1–6), together with six known compounds (7–12), were isolated from the gorgonian coral-derived fungus Aspergillus hiratsukae SCSIO 7S2001 collected from Mischief Reef in the South China Sea. Their structures, including absolute configurations, were elucidated on the basis of spectroscopic analysis and X-ray diffraction data. Compounds 1–5 and 7 showed different degrees of antibacterial activity with MIC values of 6.25–100 μg/mL. Compound 8 exhibited potent cytotoxicity against SF-268, MCF-7, and A549 cell lines with IC50 values of 12.75, 9.29, and 20.11 μM, respectively.

Synthesis and Biological Activity of Aldehyde Derivatives of Isopimaric Acid

Four series of acylhydrazone derivatives, including halogenated aryl modified acylhydrazone, thiophene, pyrrole and quinoline, were synthesized and characterized. The minimum inhibitory concentrations of the compounds against five bacteria were determined and most of the compounds displayed some degree of antibacterial activity. Isopimaric acid (pyrrole-3-carboxaldehyde) acylhydrazone (3j) exhibited the most potent activity against Streptococcus pneumonia and Klebsiella Pneumonia, with the minimum inhibitory concentration being 3.91 μg/mL. The antimicrobial activity against S. pneumoniae was improved when the pyrrole structure was introduced into isopimaric acid. All heterocyclic acylhydrazone derivatives of isopimaric acid exhibited a good in vitro antitumorial activity at 100 μM. It is concluded that the inhibitory effect of isopimaric acid (2-fluoro-6-methoxybenzaldehyde) acylhydrazone (3d) on Hep G2 and isopimaric acid (3-bromothiophene-2-carbaldehyde) acylhydrazone (3g) on Hep G2 and MDAMB 231 is better than that of the positive control 5-fluorouracil (5-FU) (76.51%), which is a widely used clinical anticancer agent, at 100 μM.

Multifunctional Modification of SIS Membrane with Chimeric Peptides to Promote Its Antibacterial, Osteogenic, and Healing‐Promoting Abilities for Applying to GBR

AbstractGuided bone regeneration (GBR) technology is the most widely used and stable method for bone defect repair. However, infectious bone defect limits the application of this technique. Herein, a small intestinal submucosa (SIS) membrane modified by chimeric peptides as a new type of GBR membrane is developed for efficacious tissue regeneration. Based on the main components of SIS membrane are I and III collagen, collagen binding peptides TKKTLRT and KELNLVY sequences are used to construct chimeric peptides with healing‐promoting peptide Hst1 or antibacterial osteogenic peptide JH8194, so as to realize the specifically target of SIS. This method achieves the fast and efficient multifunctional modification of SIS membrane. The chimeric peptides modified SIS (pSIS) membrane has satisfactory biocompatibility and a certain degree of antibacterial activity. Moreover, pSIS promotes the osteogenic related factors expression of rat bone mesenchymal stem cells and demonstrates great bone regeneration in rat skull defect model. Furthermore, pSIS accelerates the migration of oral epithelial cells in vitro and activate integrin α3β1 signal pathway contribute to wound healing. This study presents a novel biomaterial design of GBR membrane, specifically for the treatment of infectious bone defects.

Antibacterial and Bonding Properties of Universal Adhesive Dental Polymers Doped with Pyrogallol.

This study investigated the antibacterial activity, bond strength to dentin (SBS), and ultra-morphology of the polymer–dentin interface of experimental adhesive systems doped with pyrogallol (PY), which is a ubiquitous phenolic moiety that is present in flavonoids and polyphenols. A universal adhesive containing 4-META and 10-MDP was used in this study. PY behaves as an antioxidant and anti-cancerogenic agent and it was incorporated into the adhesive at different concentrations (0.5 and 1 wt.%). The antibacterial activity and SBS were analyzed and the results were statistically analyzed. The ultra-morphology of the polymer–dentin interface was assessed using scanning electron microscopy (SEM). At 24 h, a lower antibacterial activity was observed for the control adhesive compared to those with 0.5% and 1% PY. No difference was seen in SBS between the three groups at 24 h. After 6 months, the SBS of the 0.5% PY adhesive was significantly lower than the other tested adhesives. The specimens created with 1% PY adhesive presented a higher bond strength at six months compared with that found at 24 h. No morphological differences were found at the polymer–dentin interfaces of the tested adhesives. Pyrogallol may be incorporated into modern universal adhesive systems to preserve the polymer–dentin bonding interface and confer a certain degree of antibacterial activity.

Comparison of activity and components of Sophora flavescens root and seed

Infectious diseases are amongst the leading causes of morbidity and mortality. The Sophora flavescens root (traditional Chinese medicine “kushen”) is recognized as a strong anti-bacterial and anti-inflammatory Chinese herb, and widely used for clinical application. However, the ever-increasing demand for natural antibacterial agent is fostering the insufficient supply of “kushen”. This study was conducted for the first time to explore the feasibility of Sophora flavescens seed used as a supplement of Sophora flavescens root to alleviate the shortage of “kushen” resources. To accomplish this, the seed and root of Sophora flavescens were extracted by ultrasound-assisted extraction method. The antimicrobial activities of Sophora flavescens seed and root against Escherichia coli, Bacillus subtilis, Micrococcus tetragenus and Proteus species were compared by agar well diffusion method. And the phytochemical constituents from seed and root were analyzed by TLC, chromogenic reaction method, HPLC and GC/MS. The results revealed that different solvent fraction from Sophora flavescens root and seed exhibited different degrees of antibacterial activity. The chloroform fraction, ethyl acetate fraction and anhydrous ethanol fraction of Sophora flavescens root had obvious antibacterial activity. However, the best antibacterial activity of Sophora flavescens seed was achieved with the 80% ethanol extracts. Furthermore, the analysis of phytochemical compositions showed that the antibacterial-activity component profiles of Sophora flavescens seed were different from that of roots. This study clearly reveal that Sophora flavescens seed is unsuitable as a straight substitution of “kushen” due to the differences in their active component, but it has the potential to be used as a promising source of antibacterial agent, which could be utilized in clinical application and pharmaceutical industry, just as Sophora flavescens root.

Antioxidant, Cytotoxic and Antibacterial Activity and Total Phenol Contents of the Roots and the Shoots of Euphorbia macrostegia and Euphorbia microsciadia

The roots and the shoots of Euphorbia macrostegia and E. microsciadia were extracted using different solvents; dichloromethane (DCM), methanol (MeOH) and MeOH: water (80:20) and the extracts were screened for their cytotoxic, antioxidant and antimicrobial properties as well as total phenolic content. Cytotoxicity of the extracts was evaluated against human acute lymphoblastic leukemia (MOLT-4) cells by MTT reduction assay. The extracts were also subjected to the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging and Folin-Ciocalteu total phenolic assays. The MeOH extract of the shoots of E. microsciadia and DCM extract of the roots of E. macrostegia were the most cytotoxic ones with IC50 values of 10.5 ± 2.6 and 7.0 ± 1.2 µg/mL, respectively. The MeOH extract of the shoots of E. microsciadia showed considerable antioxidant activity (IC50 = 9.95 ± 1.00 µg plant extracted to scavenge 1 mL of a 0.1 mM DPPH solution), which was consistent with its highest phenolic content (288.50 ± 29.38 mg equivalent of gallic acid in 1g dry plant material: mg EG/g PM). Determination of minimum inhibitory concentrations (MICs) using the broth dilution method, confirmed that all the extracts from the plants gave various degrees of antibacterial activity against all tested microorganisms. In thin layer chromatography (TLC) investigations, some compounds previously isolated from Euphorbia species inclduing cycloartenol, 24-methylenecycloartan-3β-ol, β-sitosterol and euphol were tested and suggested to be responsible for the above-mentioned biological activities in the plants. Therefore, we suggest E. macrostegia and especially E. microsciadia as new sources for isolation and identification of various bioactive compounds.

Identification and Purification of Potential Bioactive Peptide of Moringa oleifera Seed Extracts.

The aim of the study was to investigate the antibacterial and anticoagulant activity of Moringa (Moringa oleifera) seed extracts and coagulant protein for their potential application in water treatment. Pathogenic microorganisms were obtained from Ramachandra Hospital, Chennai, India. Bacterial cell aggregation and growth kinetics studies were employed for six bacterial strains with different concentrations of seed extracts and coagulant protein. Moringa seed extract and coagulant protein showed cell aggregation against six bacterial strains, whereas seed extract alone showed growth inhibition of all six bacterial strains for up to 6 h, compared to that of control. Escherichia coli and Salmonella para typhi B did not develop resistance against coagulant protein. The results imply that Moringa oleifera is likely an efficient low-molecular bioactive peptide (with <7.5 kDa plant-based coagulant and antimicrobial peptides, confirmed by applying amino acid sequences), using liquid chromatography–mass spectrometry and HPLC, with the corresponding sequences from Napin-1A peptide posing different degrees of antibacterial activity against different pathogenic organisms.

Study on antimicrobial and antioxidant potentials of Alchornea cordifolia (Linn.): an in vitro assessment

This study investigated antimicrobial properties of Alchornea cordifolia leaf extract against a panel of selected bacterial strains. It also assessed antioxidant and phytochemical properties of the plant constituents responsible for the bioactive actions recorded. The antimicrobial potentials of the crude extract along with the fractions obtained were determined using the agar well-diffusion method. The most active fraction was partially purified by a combination of thin-layer and column chromatography; and the antimicrobial activity of the resulting samples was tested against the bacterial strains. The results showed that the leaf extract of A. cordifolia and the obtained fractions exhibited varying degrees of antibacterial activities. Phytochemical tests revealed the presence of alkaloids, flavonoids, tannins, saponins, phenols, resins, sterols, carbohydrates and terpenoids. The minimum inhibitory concentrations of the crude extracts were 0.55–4.38 mg/mL while those of the chloroform and ethyl acetate fractions were 0.08–2.50 and 0.08–0.63 mg/mL, respectively. The rate of kill assay showed that the percentage of cells killed was related to concentrations and contact time. The nucleotide and potassium ion leakage from test cells also increased with an increase in the fraction concentrations as well as the contact time intervals. Alchornea cordifolia extract exhibited 50% 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activities at 2.1 µg/mL, whereas the ascorbic acid used as standard had a half maximal inhibitory concentration (IC50) of 12.3 µg/mL. The major active constituent of the purified sample was 6-octadecanoic acid. This study showed that A. cordifolia leaf extract, which possesses antioxidant properties, exhibited significant antimicrobial activities against the test pathogens.

Antibacterial properties of Ya-Samarn-Phlae (YaSP): A pilot study on diabetic patients with chronic ulcers

Traditional healers regularly use medicinal plant preparations for the treatment of diseases; however, there are few studies supporting their claims. This study investigated the antibacterial and antibiofilm properties of Ya-Samarn-Phlae (YaSP), a traditional Thai polyherbal preparation, and its constituents (Garcinia mangostana, Oryza sativa, Curcuma longa, and Areca catechu) against infective bacteria in diabetic foot ulcers (DFUs) and assessed the wound-healing effects of a YaSP-infused oil in the treatment of DFUs). Their antibacterial and antibiofilm activities in vitro were determined in accordance with established procedures. The extracts showed various degrees of antibacterial activity against the tested pathogens, with MIC values ranging from 2 to >1000 μg/mL. G. mangostana, with its active compound alpha-mangostin, and YaSP suppressed biofilm formation by Staphylococcus epidermidis and Pseudomonas aeruginosa. A multi-center, open-label case study was performed to evaluate the safety and efficacy of YaSP-infused oil. In the second week of the treatment with YaSP-infused oil, 13 (93 %) of the 14 patients showed an improvement, with almost 50 % reduction (47.4 %–75.8 %) in the size of the treated wounds in six patients. By the fourth week of the treatment, all ulcers showed various degrees of improvement and the relative reduction in ulcer size was 55.8 ± 25.05 %. These results indicate that YaSP possesses antibacterial and antibiofilm properties, particularly against Gram-positive pathogens. The results also provide evidence for the potential application of the YaSP-infused oil in treating DFUs.

Micro-Arc Zn- and Ag-Containing Coatings for Implants with Complex Porous Architecture Obtained by 3D Printing Method from Titanium Alloy

Relevance. The creation of porous three-dimensional materials for bone defects compensation and its subsequent regeneration is an important direction of medical materials science. The key issue in the interaction of an implant and bone tissue is the surface properties of the implant.The purpose of the study is to evaluate the physicochemical properties and compatibility of tissues of a living organism and porous implants with calcium phosphate Zn- and Ag-containing formed by microarc oxidation.Materials and Methods. Implants with various types of porous structure were made by direct laser sintering of titanium alloy Ti-6Al-4V powders. The calcium phosphate coatings, including Zn- and Ag-containing, were formed on the implants surface by microarc oxidation.Results. Coatings, deposited in electrolytes of various compositions, were uniformly distributed over the implants mesh structure. The phase composition of Zn-containing coatings, deposited in the acidic electrolyte, was represented by amorphous calcium phosphates. Ag-containing coatings, deposited in the alkaline electrolyte, had an amorphous-crystalline structure, the crystalline phase of which was identified as tricalcium phosphate in the α and β modifications. The samples of extracts of calcium phosphate Zn and Ag-containing coatings were co-cultured with pFb line of the human postnatal fibroblasts for 48 hours at 37°C in 5% CO2 atmosphere. The MTT test revealed a high metabolic activity of the co-cultured fibroblasts in comparison with the fibroblasts of control.Conclusion. The pFb line of the human postnatal fibroblasts retained their viability for 48 hours of co-culturing with calcium-phosphate Zn- and Ag-containing coatings. The tested product and its components did not negatively affect the cellular respiration. However, further studies are needed to determine the rate of bioresorption and the degree of antibacterial activity of calcium-phosphate Zn- and Ag-containing coatings.

In vitro anti-bacterial activity of aqueous extracts of the whole plant, flowers, roots, leaves and stem of grass Heteropogon contortus grown in Sri Lanka

In vitro antibacterial potential of aqueous extracts of Heteropogon contortus (whole plant, leaves, flowers, stem and roots) were examined against gram negative and positive pathogen; Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 25923) respectively. Concentrations tested were 100 and 200 mg/mL, using agar well diffusion bioassay technique. Gentamicin (1µg/mL) was used as the positive control and distilled water as the negative control. The results revealed that different parts of the plant exhibit different degrees of antibacterial activity. The ranking of the potency of antibacterial activity against Escherichia coli was whole plant > leaves > flowers > root > stem, while whole plant > flowers > roots > leaves > stem for Staphylococcus aureus. Phytochemical analysis revealed the presence of alkaloids, flavonoids, diterpenes and glycosides in certain parts of the plant while phenols, proteins and amino acids were found in all parts. The antibacterial activity is likely to be mediated by synergistic action via multiple mechanisms. A strong possibility exists to develop a safe and potent antibacterial agent from Heteropogon contortus.

PH-Dependent Antibacterial Activity of Glycolic Acid: Implications for Anti-Acne Formulations

Glycolic acid is the smallest alpha hydroxy acid and widely used for skincare applications, including to treat acne vulgaris. Oftentimes, high concentrations of glycolic acid (~20–50 vol%) are incorporated into chemical peels to reduce acne-related inflammation while there is an outstanding need to determine to what extent glycolic acid can potently inhibit Cutibacterium acnes (formerly known as Propionibacterium acnes), which is a Gram-positive bacterium implicated in acne pathogenesis. Herein, we report that glycolic acid exhibits pH-dependent antibacterial activity against C. acnes and mechanistic studies identified that the nonionic form of glycolic acid is more active than the anionic form. The degree of antibacterial activity, including minimum bactericidal concentration (MBC), of glycolic acid was evaluated in the pH range of 3 to 4.5, and the greatest potency was observed at pH 3. In light of skincare formulation needs, we selected the pH 3.5 condition for further testing and determined that glycolic acid kills C. acnes cells by disrupting bacterial cell membranes. While most conventional treatments involve high concentrations of glycolic acid (>20%), our findings support the potential of developing anti-acne formulations with glycolic acid concentrations as low as 0.2% and with pH conditions that are suitable for over-the-counter applications.

Comparison of Antimicrobial Activity between Ethanolic Extract and Essential Oil of Ginger (Zingiber officinale) against Food-borne Bacteria

Background: Ginger (Zingiber officinale) is one of the most well-known spices with antimicrobial activity. However, different extraction methods of ginger will result in different antimicrobial properties due to the various substances extracted. This study aimed to compare antimicrobial activity between ethanolic extract and essential oil of ginger against food-borne bacteria grown in 2.1% Mueller Hinton agar. Methods: Fresh ginger rhizomes were extracted either by using vapor distillation method or maceration using ethanol to obtain ginger essential oils (GEO) and ginger ethanolic extract (GEE), respectively. Ethanolic extract and essential oil of ginger at different concentrations were then tested for their antimicrobial activity using disk diffusion method against Escherichia coli, Bacillus subtilis, Salmonella typhi, and Staphylococcus aureus. Tetracycline was also used as a standard of antibacterial agent. Results: Ginger essential oil in 25%, 50%, and 100% showed significant growth inhibition of four types of bacteria compared to ginger ethanolic extract. This antimicrobial effect of ginger essential oil was shown to be dose-dependent. However, it has been demonstrated that ginger ethanolic extract 50% and 100% has a stronger antimicrobial effect against B.subtilis. Conclusion: Ginger essential oil and ethanolic extract showed different degree of antibacterial activity against food-borne bacteria due to compound contained within respective extracts, with a higher degree of activity found in ginger essential oil. These may show that different ginger extract may have different antibacterial activity.

Antibacterial activity and effects of aromatic derivatives on denture base polymerization

This study assessed the effect of copolymerization on the microbiota of the oral cavity. The plant extraction was converted into aromatic derivatives, which were added to methyl methacrylate monomer. Fourier transform infrared spectroscopy spectra showed no negative effects of these additives on the polymerization process. All the assayed derivatives displayed some degree of antibacterial activity.