Considerable Antimicrobial Activity Research Articles

Chromatographic profiles and antimicrobial activity of the essential oils obtained from some species and cultivars of the Mentheae tribe (Lamiaceae).

The present study was focused on the chemical composition and antimicrobial activity of the essential oils (EsO) obtained from five Lamiaceae representatives grown in the south of Ukraine. Among them are Salvia sclarea L., Monarda didyma (cultivar ‘Cambridge Scarlet’), Thymus pulegioides (cultivar ‘2/6-07’), Thymus vulgaris (cultivar ‘Jalos’), and Thymus serpyllum L. The component analysis of the EsO was carried out by gas chromatography method coupled with mass spectrometry (GC–MS). The antimicrobial properties of the EsO were determined using the agar diffusion test against widespread pathogenic bacterial strains (Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, Streptococcus pyogenes) and opportunistic yeast Candida albicans. The EsO of Thymus serpyllum and Thymus vulgaris (cultivar ‘Jalos’) displayed noteworthy antibacterial properties against a wide spectrum of the microorganisms. These antimicrobial properties could be attributed to the high content of aromatic monoterpenoid thymol (52.56% and 47.33%, respectively). The EsO of Salvia sclarea with the dominance of linalyl acetate (45.51%) and linalool (38.98%) as well as Thymus pulegioides (cultivar ‘2/6-07’) containing α-citral (27.10%) and β-citral (17.11%) demonstrated the strongest antimicrobial effects on typical and clinical strains of Staphylococcus aureus with the inhibition zones in the range of 24.0–31.0 mm. The Salvia sclarea EsO demonstrated the most significant effect against clinical strains of Candida albicans. In conclusion, the present study revealed the chemical composition of five Lamiaceae species and cultivars grown in the south of Ukraine and considerable antimicrobial activity of the tested EsO, especially against the typical and clinical strains of Staphylococcus aureus and Candida albicans. The obtained results could be perspective for applying in the pharmaceutical industry and for the conservation of food and cosmetic products.

Impacts of Supplementing Broiler Diets with Biological Curcumin, Zinc Nanoparticles and Bacillus licheniformis on Growth, Carcass Traits, Blood Indices, Meat Quality and Cecal Microbial Load.

Simple SummaryThe present study aimed to investigate the beneficial effects of zinc nanoparticles (ZnNPs) and curcumin nanoparticles (CurNPs) as well as Bacillus licheniformis (Bl) supplementation on broiler growth, chemical blood indices, and cecal microbes. The results showed considerable antimicrobial activity against pathogenic bacteria and fungi with ZnNPs and CurNPs supplementations. At the same time, ZnNPs, CurNPs, and Bl improved broiler performance, carcass traits, meat quality traits, and some blood indices. Therefore, the inclusion of ZnNPs, CurNPs, and Bl is recommended for broiler feeding regimens to improve the performance and health status.The current study aimed to investigate the influence of dietary zinc nanoparticles (ZnNPs), curcumin nanoparticles (CurNPs), and Bacillus licheniformis (Bl) on the growth, carcass, blood metabolites, and the count of some cecal microorganisms of Indian River (IR) broilers. Chicks were allotted into seven experimental groups: control group, 1st, 2nd and 3rd groups were given diets enriched with ZnNPs, CurNPs and Bl (3.0, 5.0 and 2.0 cm3/kg diet, respectively). The 4th, 5th and 6th groups were given diets supplemented with ZnNPs (3.0) + Bl (2.0) (ZP); ZnNPs (3.0) + CurNPs (5.0) (ZC) and ZnNPs (3.0) + CurNPs (5.0) + Bl (2.0) (ZCP) cm3/kg diet, respectively. The results revealed that ZnNPs and CurNPs exhibited a considerable antimicrobial activity against pathogenic bacteria and fungi. They also inhibited the growth of microbes in a range of 50–95 µg/mL. The diet supplemented with ZnNPs, CurNPs, and Bl increased the body weight compared to the control after five weeks of age. Additionally, values of daily feed intake increased in these groups; however, the feed conversion ratio decreased. All values of carcass traits were better than that of the control. The treatments led to decreased abdominal lipids compared to the control. The activity of liver enzymes and malondialdehyde (MDA) activity decreased in the treated groups. In a converse trend, the levels of oxidative enzymes, amylase, protease, lipase and immunoglobulin were higher than that of the control. Meat quality properties were improved and cecal microbial counts were decreased. In conclusion, the ZnNPs, CurNPs, and Bl improved the broiler’s weights, carcass traits, meat quality traits, as well as some blood indices and cecal microbial load. Therefore, the inclusion of ZnNPs, CurNPs, or Bl is recommended for broiler feeding regimens to improve the performance and health status.

English

BACKGROUND Azadirachta indica, commonly known as neem, neem tree or Indian lilac, Limbo, Nim, Nimba, Medusa and Vempu. It is typically grown in tropical and subtropical regions. Neem belongs to family meliaceae. Neem is a native tree of India. It is also called “village pharmacy of south Asia” (India) because of its enormous medicinal properties and people use it most of the time without knowing its multiple advantages. This study was done to know the efficacy of medicinal plant named Azadirachta indica (Neem) against pathogenic microorganisms and about its utility as disinfectant and floor cleaner. METHODS Agar well diffusion method, Culture plate method, inoculum preparation & its subculture methods were used to determine the antimicrobial activity of the neem leaf extract. Different concentrations of neem leaf extracts in culture plates were used for the study. In this method inhibited zones were measured. RESULTS Neem leaf extracts showed considerable antimicrobial activity against four target pathogens. In agar well diffusion method it showed maximum antimicrobial activity against Enterococcus and Staphylococcus aureus. Growth of inhibition was increased as the concentration of the neem extract in agar media increased and was maximum for Staphylococcus aureus. CONCLUSIONS The extract of A. indica, has antimicrobial activity against target pathogens Enterococcus, Staphylococcus aureus, Pseudomonas, and E.coli. With the old medicinal knowledge on neem, better economic and therapeutic utilization can be done by using modern approaches of drug development. KEY WORDS Neem Leaf extract, Antimicrobial Activity, Agar Well Diffusion Test, Zone of Inhibition

Preparation of new biocompatible polymeric nanofibers containing Daphne macronata extract and evaluation of its antimicrobial activity

Background and Objective: Daphne mucronata is one of the species of Daphne genus in Iran that has unique biological properties and has been used as a medicinal plant for a long time. In this study, biocompatible polymer nanofibers by polyvinyl alcohol and Daphne macronata extract were prepared as a high-efficiency antimicrobial coating by electrospinning method, and its antimicrobial activity on three species of Gram-positive and two species of Gram-negative bacteria and one species of fungi were investigated.Experimental: In this study, a polymer solution with a weight/weight percentage of 12% polyvinyl alcohol polymer was prepared and 2 ml of plant extract was added to 10 ml of a polymer solution. To produce nanofibers, the optimum parameters of the electrospinning device including 17 kV voltage, injection rate 3 mL.h-1, tip needle to collector distance 7 cm, and collector speed 100 rpm were adjusted. Results: After preparing the polymer layer, the morphology and diameter of the nanofibers were determined with the scanning electron microscope, and the average diameter of the nanofibers produced under optimal conditions was 80 nm. Examination of the antimicrobial activity of this coating showed that the structure has a considerable antimicrobial activity on bacteria so that the greatest antimicrobial effect on Gram-positive bacterium was observed against Staphylococcus pyogenes with an inhibition zone diameter of 14 mm.Conclusion: As a result, this compound can be used as an antimicrobial coating in biology and medicine for packing or wound dressings.

An Innovative Method Designed for the Synthesis of Some New Mixed Ligand Ni(II) Complexes Its Characterization and Applications

In the present work, a series of new mixed ligand Ni(II) complexes of the type [Ni(P)(L).2H2O] have been synthesized by using 2-amino-6-methyl pyrimidine-4-ol (HP), a primary ligand and N- and O- donor amino acids (HL) secondary ligands. Synthesis of Ni(II) complexes has been carried out by thermal and microwave methods. Results show that complexes synthesized by the microwave method were more efficient than the thermal method. Preparation time in the microwave method was short (4-7 min.) as compared to the thermal method (45 min.). Additionally, the microwave technique gave a very high yield (90%) of the complexes. The prepared complexes were characterized by Gouy experiment, FTIR, elemental analysis, TGA, and DTA at room temperature. The complexes have shown considerable antimicrobial activities such as antifungal and antibacterial activity.

Bioactive peptides supplemented raw buffalo milk: Biological activity, shelf life and quality properties during cold preservation.

This study aimed to prolong the raw buffalo milk handling and cold storage period by controlling the microbes, enhancing sensory properties and their functionality after supplementing bioactive peptides. The additions included hen and duck egg white protein isolates (HPI and DPI), pepper seed protein (PSP), and pepsin-kidney bean protein hydrolysate (PKH). Five milk treatments were prepared and evaluated as non-supplemented milk (M- Control), hen egg white protein isolate-supplemented milk (M-HPI), duck egg white protein isolate-supplemented milk (M-DPI), pepper seeds protein-supplemented milk (M-PSP), and kidney bean hydrolysate-supplemented milk (M-PKH). Pyrogallol, protocatechuic, catechin, benzoic and caffeine were the main phenolic compounds, Apignin-6-arabinose, naringin, hesperidin, naringenin, kaempferol 3-2-p-comaroyl were the dominant flavonoids in milk samples based on HPLC profile. During 30days of cold storage, the antioxidant potential of peptides-supplemented milk samples was significantly decreased (p≤0.05) as decrement of phenolic compounds and flavonoids; the pH was nearly stable, the titratable acidity and total soluble solids (TTS) were (p≤0.05) raised. PSP and PKH were inhibited (p≤0.05) the decay of sugars in M-PSP, and M-PKH by reducing 45% of bacterial load as compared to other milk samples. PSP was significantly (p≤0.05) scavenged 87% of DPPḢ compared to other peptides. Besides, PSP followed by PKH reduced considerably (p≤0.05) the growth of tested bacteria, molds, and yeasts. The PSP has significantly increased the whiteness of M-PSP as compared to other milk samples. M-PSP had the highest score in color, taste, and flavor, followed by M-PKH.

Design, multistep synthesis and in-vitro antimicrobial and antioxidant screening of coumarin clubbed chalcone hybrids through molecular hybridization approach

In the present study we designed and synthesized 26 coumarin clubbed chalcone hybrids (1–13 and 14–26) in good yields (54.32–74.25%) and further tested for their antimicrobial and antioxidant activities considering the potential bioactivities of these two pharmacophores. All Spectroscopic techniques including FT-IR, 1H NMR, 13C NMR and mass were used to characterize the compounds. The antimicrobial and antioxidant activities of these compounds were performed by agar well diffusion method and DPPH free radical assay respectively. The compounds elicited considerable antimicrobial and potential antioxidant activities. Bioactivity data designated that the compounds 1 and 7 with no and 4-Cl substitution on the phenyl ring of coumarin clubbed chalcones with 3,4-dihydropyrimidine-2-one displayed antibacterial activity with minimum inhibitory concentration (MIC) value of 10 µM and 17 µM against Staphylococcus aureus and MIC value of 8 µM and 13 µM against Escherichia coli and antifungal activity with MIC value of 10 µM and 11 µM against Aspergillus niger respectively. On the other hand, coumarin clubbed chalcones with 3,4-dihydropyrimidine-2(1H)-thione scaffold (14–26) exhibited potential antioxidant activity. Among them, compounds 22 containing electron releasing 2-OH substituent was the most active with 77.92% scavenging activity, followed by 14 and 26 (75.22% and 71.32%). The promising leads evolved through this investigation are important for the future development of novel and potential antioxidant compounds.

Indigenous Knowledge Affords Antimicrobial Plants for the Management of Infections

Aim: The research was carried out to ascertain the antimicrobial effect of the plants Omphalocarpum ahia, Homalium letestui, and Coelocaryon oxycarpum, which are used locally to treat some infectious diseases.
 Place and Duration of Study: Department of Biomedical Sciences, School of Allied Health Sciences, University of Cape Coast, Cape Coast, Ghana and Department of Herbal Medicine, KNUST, Ghana from June to August 2014.
 Method: The stem barks of the plants were extracted with 70 % methanol and successively partitioned with petroleum ether, ethyl acetate, methanol to obtain three different fractions. The antimicrobial activities of the extracts and fraction against MRSA, S. typhi, E. coli, S. pneumoniae, P. aeruginosa, E. faecalis, and S. aureus were determined using the disk diffusion method and the minimum inhibition concentration by the serial microplate dilution method with 0.2 mg/ml p-iodonitrotetrazolium as growth indicator whereas gentamycin was used as the positive control. Phytochemical tests on the plant materials were done according to standard methods.
 Result: All the fractions of each plant had activity against some of the bacteria. Ethyl acetate (EA) and hydro-methanolic (CE) extracts of Coelocaryon oxycarpum exhibited activity against all selected bacteria with MIC ranging from 0.625-5 mg/ml for CE and 0.3125-5 mg/ml for EA. Hydro-methanolic (CE) extracts of Omphalocarpum ahia also exhibited antibacterial activity against all the selected bacteria.
 Conclusion: The current research showed that Omphalocarpum ahia and Coelocaryon oxycarpum have considerable antimicrobial activity against all the strains used in the study. Local knowledge may afford lead materials for the development of novel antimicrobial agents.

Evaluation of antimicrobial activity of leaf extract of Gymnema sylvestre

The present study was designed with the main aim to evaluate antimicrobial activity of aqueous leaf extract of Gymnema sylvestre against pathogenic microorganisms. Leaves of G. sylvestre was subjected to successive solvent extraction by continuous hot extraction (Soxhlet) with water. The extracts were diluted in dimethyl sulfoxide (DMSO) before testing the antimicrobial activity. The antimicrobial activity of extract for B. subtilis, K. aerogenus, S. aureus, E. coli, A. niger and P. chrysogenium was determined by agar well diffusion technique. The results of the present study revealed that aq. leaf extract of G. Sylvestre exhibited zones of inhibition at 100 mg/ml concentration. Aq. leaf extract of G. sylvestre exhibited zone of inhibition zone bacterial species like B. subtilis (10.55 mm), K. aerogenus (11.00 mm), S. aureus (8.50 mm), E. coli (12.50 mm), and against fungal species like A. niger (10.00 mm). In conclusion, present preliminary study delineated that the aqueous extract of G. sylvestre possesses considerable antimicrobial activities against B. subtilis, S. aureus, E. coli, K. aerogenes and A. niger. Hence, further experiments like isolation and purification of phytoactives of G. sylvestre responsible for antimicrobial activities could be recommended to carry out to further enhance the antimicrobial activities of phytoactives present in aq. leaf extract of G. sylvestre.

Essential Oil of Deverra tortuosa Aerial Parts: Detailed Chemical Profile, Allelopathic, Antimicrobial, and Antioxidant Activities.

Essential oils (EOs) are a promising group of natural products of the aromatic plants due to their various biological effects such as allelopathic, antioxidant, antimicrobial activities. The present study aimed to construct the detailed chemical profile of the EO derived from Deverra tortuosa aerial parts along with assessing its allelopathic, antimicrobial, and antioxidant potentialities. The EO was extracted by hydrodistillation and analyzed via gas chromatography-mass spectrometry (GC/MS). The allelopathic activity of the EO was assessed against the germination and seedling growth of the weed Chenopodium murale. Also, the EO was tested against five microbes. The antioxidant activity was determined using the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). The GC/MS analysis of EO revealed the presence of 86 compounds with a preponderance of oxygenated sesquiterpenes and monoterpene hydrocarbons. Widdrol, β-phellandrene, piperitol, cubedol, α-terpinene, (E)-10-heptadecen-8-ynoic acid methyl ester, citronellyl tiglate, and m-cymene were the major compounds. A comparative profile was established between the EOs constituents of our study with the documented EOs of D. tortuosa and the other Deverra species around the world via agglomerative hierarchical clustering (AHC) and principal components analysis (PCA). The EO showed a substantial allelopathic activity against C. murale, as well as it showed considerable antimicrobial and antioxidant activities. Thereby, the EO of D. tortuosa could be considered as a promising environmental-friendly bioherbicide against weeds. Also, it could be integrated into food preservation due to its potent antimicrobial and antioxidant activities. However, further study is recommended for more characterization of the major compounds and evaluation of their activities, either singular or synergistic, and assess their efficiency and biosafety.

Enhancing quality and safety of raw buffalo meat using the bioactive peptides of pea and red kidney bean under refrigeration conditions

The aim of this study was to extend the shelf life of raw buffalo meat by coating with high solubility bioactive peptides (BPs). In this work, BPs (11S) of pea and red kidney beans were obtained by different isolation techniques. Alcalase-red kidney bean hydrolysate (RBAH) successfully obtained after 60 min enzymatic hydrolysis for red kidney bean protein isolate (RPI) by Alcalase (E/S ratio of 1:100, hydrolysis degree 30%). The 11S pea globulin (11SGP) was isolated from pea total protein by ammonium sulphate. BPs were characterised by SDS-PAGE and used as a shield coated raw buffalo meat because of their basic nature. The isolated peptides have considerable antioxidant and antimicrobial activity. The antioxidant activity was estimated by DPPH assay. The antibacterial activity was evaluated by well diffusion assay; however, antifungal activity was estimated by disc diffusion assay. RBAH and 11SGP (800 µg/mL) were significantly (p ≤ .05) scavenged 90, 92% of DPPH˙, however, 60 µg/mL concentration was significantly (p ≤ .05) reduced 48–89% of gram-positive, and 38–82% of gram-negative bacteria, respectively, and they were inhibited 88% of fungal growth. The BPs (400 µg/g) were significantly reduced (p ≤ .05) the increment of meat pH and myoglobin oxidation to an acceptable percentage of metmyoglobin (MetMb) (40%) for 15–20 d via eliminating 44% of bacterial load and maintained secured storage for two weeks. RBAH was significantly increased (p ≤ .05) a*, and b* values and enhanced the meat redness, but a* value was decreased during storage. RBAH and 11SGP (400 µg/g) (p ≤ .05) was maintained the meat colour and odour by 48–68% and 64–73% after two weeks of cold storage, respectively. The tested peptides could be safely applied in novel foods. Highlights 11SGP and RBAH are high solubility bioactive peptides (BPs) with antioxidant and antimicrobial activity. 11SGP and RBAH reduce myoglobin oxidation to an acceptable percentage of met-myoglobin. RBAH enhances the whiteness and redness of buffalo meat. 11SGP and RBAH extend meat shelf life for a period exceeds 15 d at 4 °C. Graphical

Antibacterial effectiveness of natural products alone and in combination with Calcium Hydroxide as Intracanal Medicaments : An In-Vitro Microbiological Study

Major objective of root canal treatment is disinfection of the root canal system and elimination of microbiota. Various intracanal medicaments as an adjunct to mechanical disinection and irrigation have been used but due to the harmful effects of the commercially available agents, a need for natural alternatives is felt over the time. This in-vitro study aims to evaluate the antibacterial effectiveness of natural agents Septillin and Aloe vera with Calcium hydroxide and without Calcium hydroxide on the Streptococcus mitis, E. Faecalis and Candida albicans using agar well diffusion method. The antibacterial activity was assessed by the diameter of zone of inhibition seen as clear zone around the wells. The study showed that Septillin in combination with Calcium hydroxide and alone showed considerable antimicrobial activity against Streptococcus mitis, Enterococcus faecalis and Candida albicans where as Aloe vera with Calcium hydroxide showed to be mildly effective against all three but not as effective as Septillin and Calcium hydroxide when tested alone.

Cryogel/hydrogel biomaterials and acupuncture combined to promote diabetic skin wound healing through immunomodulation

Unhealed chronic wounds often deteriorate into multiple infection with several kinds of bacteria and excessive proteolytic wound exudate and remains one of the common healthcare issues. Here, the functional and antimicrobial hydrogel and cryogel biomaterials were prepared from glycol chitosan and a novel biodegradable Schiff base crosslinker difunctional polyurethane (DF-PU). The cryogel exhibited ~2730 ± 400% of water absorption with abundant macropores and 86.5 ± 1.6% of porosity formed by ice crystal as well as ~240% cell proliferation effect; while the hydrogel demonstrated considerable antimicrobial activity and biodegradability. As an optimized procedure to treat the diabetic skin wound in a rat model, the combined application of adipose stem cell-seeded cryogel/hydrogel biomaterials on the wound and acupuncture surrounding the wound may attain 90.34 ± 2.3% of wound closure and secure the formation of granulation tissue with sufficient microvessels and complete re-epithelialization in 8 days. The average increases in the superficial temperature of wounded animals after acupuncture were about 1–2 °C. Through the activation of C3a and C5a, the increased secretion of cytokines SDF-1 and TGFβ-1, as well as the down-regulation of proinflammatory cytokines TNF-α and IL-1β, the combined treatment of stem cell-seeded cryogel/hydrogel biomaterials and acupuncture on wounds produced synergistic immunomodulatory effects. The strategy using the combined treatment of biomaterials, stem cells, and acupuncture reveals a perspective new approach to accelerate the tissue regeneration.

Mechanochemical P-derivatization of 1,3,5-Triaza-7-Phosphaadamantane (PTA) and Silver-Based Coordination Polymers Obtained from the Resulting Phosphabetaines.

We have described earlier that in aqueous solutions, the reaction of 1,3,5-triaza-7-phosphaadamantane (PTA) with maleic acid yielded a phosphonium-alkanoate zwitterion. The same reaction with 2-methylmaleic acid (citraconic acid) proceeded much slower. It is reported here, that in the case of glutaconic and itaconic acids (constitutional isomers of citraconic acid), formation of the corresponding phosphabetaines requires significantly shorter reaction times. The new phosphabetaines were isolated and characterized by elemental analysis, multinuclear NMR spectroscopy and ESI-MS spectrometry. Furthermore, their molecular structures in the solid state were determined by single crystal X-ray diffraction (SC-XRD). Synthesis of the phosphabetaines from PTA and unsaturated dicarboxylic acids was also carried out mechanochemically with the use of a planetary ball mill, and the characteristics of the syntheses in solvent and under solvent-free conditions were compared. In aqueous solutions, the reaction of the new phosphabetaines with Ag(CF3SO3) yielded Ag(I)-based coordination polymers. According to the SC-XRD results, in these polymers the Ag(I)-ion coordinates to the N and O donor atoms of the ligands; however, Ag(I)-Ag(I) interactions were also identified. The Ag(I)-based coordination polymer (CP1.2) formed with the glutaconyl derivative of PTA (1) showed considerable antimicrobial activity against both Gram-negative and Gram-positive bacteria and yeast strains

Bioactive peptides fractions from traditional Iranian Koopeh cheese; lactic fermentation products

Koopeh is a traditional Iranian cheese produced from raw milk of sheep or cow, famous for its specific taste and ripening process. In this study, the antimicrobial and antioxidant activities of water-soluble extracts (WSEs) from different Koopeh cheese samples (C1–C8) were evaluated. The WSEs had considerable antimicrobial activity against Pseudomonas aeruginosa, Bacillus cereus and Salmonella enterica. Free radical scavenging of ABTS and DPPH ranges were 56.5–89.9% and 48.7–77.8%, respectively, while iron chelating activities of up to 88.8% were demonstrated. Samples with maximum antioxidant activity (C3 and C5) were selected for further analysis. Different ultrafiltrated fractions (<2, 2–10, and >10 kDa) of C3 and C5 samples were tested, and the 2–10 kDa fraction of C3 showed the highest antioxidant activity. Based on MALDI-TOF/MS analysis, peptides with molecular weights of 3896.91, 3937.42, 3926.57, 3702.51 and 3692.87 Da were dominant in 2–10 kDa fraction. Our results indicated that Koopeh cheese is a potential functional food, and that its peptide fractions can be employed in nutraceutical formulations.

Transcriptomic Analysis of Staphylococcus aureus Under the Stress Condition Caused by Litsea cubeba L. Essential Oil via RNA Sequencing.

Litsea cubeba L. essential oil (LCEO) is a natural essential oil with considerable antimicrobial activity, and it can gradually replace some chemical additives in the food industry. However, the genetic evidences of stress response of bacteria under sub-lethal treatment with LCEO is limited. To this end, transcriptomic analysis of Staphylococcus aureus 29213 under a low concentration of LCEO was performed. Bacterial RNA samples were extracted from 1/4 MIC (0.07 μL/mL) of LCEO-treated and non-treated S. aureus 29213. The transcriptional results were obtained by RNA sequencing (RNA-Seq). After treated with LCEO of S. aureus 29213, 300, and 242 genes were significantly up and down-regulated. Up-regulated genes were mainly related to cell membrane (wall) stress stimulon including genes related to two-component regulatory system (VraS), histidine metabolism (hisABCD etc.) and L-lysine biosynthesis (thrA, lysC, asd etc.). Significant differences were also founded between LCEO-treated and non-treated groups in peptidoglycan biosynthesis related pathways. Down-regulated genes were related to nitrogen metabolism (NarGHIJ etc.), carotenoid biosynthesis (all) and pyruvate metabolism (phdA, pflB, pdhC etc.) of S. aureus 29213 in an LCEO-existing environment compared to the control. At the same time, we confirmed that LCEO can significantly affect the staphyloxanthin level of S. aureus 29213 for the first time, which is closely related to the redox state of S. aureus 29213. These evidences expanded the knowledge of stress response of S. aureus 29213 strain under sub-lethal concentration of LCEO.

Antibiofilm activity of lactoferrin-derived synthetic peptides against Pseudomonas aeruginosa PAO1.

Many pathogenic bacteria can protect themselves from the effects of antibiotics and the host immune response system by forming biofilms. Biofilms are polymer-entrapped bacterial cells, which adhere to each other and are often attached to a surface. Eradication of bacterial biofilms typically requires much higher concentrations of antibiotics than are normally needed to kill cultured planktonic cells, raising serious clinical concerns. In an attempt to prevent the formation of biofilms or to break up existing biofilms of pathogenic bacteria, herein we have used the standard crystal violet assay as well as the Calgary biofilm device to test several lactoferrin- and lactoferricin-derived antimicrobial peptides for their antibiofilm activity against Pseudomonas aeruginosa PAO1. Our results revealed that the short bovine lactoferricin-derived RRWQWR-NH2 (20-25) hexapeptide has no activity against P. aeruginosa PAO1. Moreover, the longer human lactoferricin-derived peptide GRRRRSVQWCA (1-11) and the bovine lactoferrampin (268-284) peptide were also almost devoid of activity. However, several different "mix-and-match" dimeric versions of the two lactoferricin-derived peptides proved quite effective in preventing the formation of biofilms at low concentrations, and in some cases, could even eradicate an existing biofilm. Moreover, the full-length bovine lactoferricinB (17-41) peptide also displayed considerable antimicrobial activity. Some of the longer lactoferricin-derived dimeric peptides acted through a bactericidal mechanism, whereas others seemed to interfere in cell-signalling processes. Taken together, our results indicate that synthetic dimeric peptides comprising short naturally occurring human and bovine lactoferricin constructs could be further developed as antibiofilm agents.

Antibacterial activity of Turkish honey against selected foodborne pathogens

Honey is an important animal product that is consumed by people of all ages and has become an important antimicrobial agent because it has both antibacterial properties and does not cause microbial resistance. Although, Turkey is among the most important honey producers of the world, there are not enough studies about the antibacterial activity of Turkish honey. According to their geographical area, honey exhibit considerable and variable antimicrobial activity. In this study, we investigated the in vitro antibacterial effect of honey obtained from Turkey, against Escherichia coli, Listeria monocytogenes, Salmonella Typhimurium and Staphylococcus aureus by using agar dilution, agar well diffusion and disc diffusion methods and compared the efficacy of these methods. Results showed the antibacterial effects of Turkish honey, collected from different regions against selected pathogens. Different concentrations of all honey samples displayed an antibacterial activity. Each microorganism exhibited different sensitivity to the honey tested. In addition, a significant difference was detected between the three methods for each microorganism and well diffusion method was found to be the most sensitive method.

Synergistic Potential of the Leaves of Aspillia africana (Compositae) and Psidium guajava (Myrtaceae) Against Some Selected Bacterial and Fungal Isolates

Background: The plethora of secondary metabolites inherent in plants that could be synthesized and formulated into useful drugs for the treatment of diseases is not fully understood. This study was carried out to evaluate the antimicrobial potential of the leaves of Aspillia africana and Psidium guajava plants on some selected bacterial and fungal isolates.Methodology: Fresh and matured leaves of Aspillia africana and Psidium guajava were collected at the Federal College of Agriculture, Akure and Obafemi Awolowo University (OAU), Ile-Ife. The plants were identified and voucher deposited at the Herbarium unit of the Department of Botany, Obafemi Awolowo University, Ile-ife. The pure isolates of the bacteria and fungi were obtained from Department of Microbiology, Obafemi Awolowo University, Ile-Ife, Nigeria. The bacteria isolates were maintained on nutrient agar slant and the fungal isolates on PDA. Extraction of the plant materials using methanol, ethanol and aqueous fractions were carried out using standard protocols. The isolates were inoculated on a nutrient broth. Minimum Inhibitory Concentration (MIC) of the extracts was determined by broth dilution method while minimal bactericidal and fungicidal concentrations respectively were determined following established protocols.Results: The results showed that Bacillus cereus, Cornybacterium pyogenes, Klebsiella pneumonia and Escherichia coli were all resistant to the plant extracts. The fungal isolates; Candida albicans, Tryptophyton rubrum, Penicillium expansium, and Aspergillus flavus were resistant to Psidium guajava extract as no significant activity was observed. All the plant extracts produced considerable antimicrobial activities with Streptococcus faecalis and Staphyloccocus. aureus. whereas, these organisms were resistant to ofloxacin, sparfloxacin, chloramphenicol, augmentin, ciprofloxacin and septrin.Conclusion: This study revealed that the therapeutic properties of Aspillia africana and Psidium guajava are better enhanced with their synergistic potential to the tested microorganisms.Keywords: Aspillia africana; Bactericidal; Psidium guajava; Synergistic;therapeutic.Background: The plethora of secondary metabolites inherent in plants that could be synthesized and formulated into useful drugs for the treatment of diseases is not fully understood. This study was carried out to evaluate the antimicrobial potential of the leaves of Aspillia africana and Psidium guajava plants on some selected bacterial and fungal isolates.Methodology: Fresh and matured leaves of Aspillia africana and Psidium guajava were collected at the Federal College of Agriculture, Akure and Obafemi Awolowo University (OAU), Ile-Ife. The plants were identified and voucher deposited at the Herbarium unit of the Department of Botany, Obafemi Awolowo University, Ile-ife. The pure isolates of the bacteria and fungi were obtained from Department of Microbiology, Obafemi Awolowo University, Ile-Ife, Nigeria. The bacteria isolates were maintained on nutrient agar slant and the fungal isolates on PDA. Extraction of the plant materials using methanol, ethanol and aqueous fractions were carried out using standard protocols. The isolates were inoculated on a nutrient broth. Minimum Inhibitory Concentration (MIC) of the extracts was determined by broth dilution method while minimal bactericidal and fungicidal concentrations respectively were determined following established protocols.Results: The results showed that Bacillus cereus, Cornybacterium pyogenes, Klebsiella pneumonia and Escherichia coli were all resistant to the plant extracts. The fungal isolates; Candida albicans, Tryptophyton rubrum, Penicillium expansium, and Aspergillus flavus were resistant to Psidium guajava extract as no significant activity was observed. All the plant extracts produced considerable antimicrobial activities with Streptococcus faecalis and Staphyloccocus. aureus. whereas, these organisms were resistant to ofloxacin, sparfloxacin, chloramphenicol, augmentin, ciprofloxacin and septrin.Conclusion: This study revealed that the therapeutic properties of Aspillia africana and Psidium guajava are better enhanced with their synergistic potential to the tested microorganisms.

Analysis of the Antimicrobial, Cytotoxic, and Antioxidant Activities of Cnidium officinale Extracts.

This study analyzed the antimicrobial, cytotoxic, and antioxidant properties of Cnidium officinale (CO) extracts to confirm their antimicrobial activity toward oral microorganisms. The control group contained 0 μg/mL of CO, and the experimental groups contained 50, 100, 150, and 200 μg/mL of CO. To confirm the antibacterial activity of CO extracts against microorganisms in the oral cavity, an inhibition zone test, a colony-forming unit (CFU) analysis, an optical density (OD) evaluation, and a SEM (scanning electron microscopy) analysis were performed. A cytotoxicity test was also conducted to determine cell viability, and the contents of flavonoids and polyphenols were measured to analyze the extract components. In the control group, the growth inhibition zone increased, while the CFU and OD values decreased (p < 0.05). The SEM analysis confirmed that the number of microorganisms for both the microbes decreased. The cell viability was more than 80% in both the control and experimental groups, excluding the 200 μg/mL sample. The flavonoid and polyphenol contents in the experimental groups showed higher values than those of the control group. Therefore, the CO extract showed considerable antimicrobial activity toward both Streptococcus mutans and Candida albicans, suggesting that it may be used as a natural antimicrobial agent for dental applications.