Variable Antimicrobial Activity Research Articles

ANTIMICROBIAL ACTIVITY OF OILS FROM PUMKIN SEEDS, GRAPE SEEDS AND SEA-BUCKTHORN FRUITs

Currently, the search for new alternative effective sources for obtaining compounds with antimicrobial activity does not lose its relevance. Aim. To investigate the antimicrobial activity of oils obtained by cold pressing from pumpkin seeds, grape seeds and sea-buckthorn fruits. Methods. Antimicrobial activity of oils from pumpkin seeds, grape seeds and sea-buckthorn fruits against strains of indicator microorganisms Staphylococcus aureus АТСС 25923, Micrococcus luteus АТСС 4698, Enterococcus faecalis АТСС 29212, Bacillus subtilis АТСС 6633, Kocuria rhizophila DSM 3480, Escherichia coli АТСС 25922, Proteus vulgaris АТСС 6896, Salmonella enterica NCTC 6017, Klebsiella pneumoniae АТСС 10031, Pseudomonas aeruginosa АТСС 27853, Pseudomonas putida KT 2440 and Candida albicans АТСС 18804 was determined on semi-liquid LB medium by the well method. Results. All tested plant oils showed antimicrobial activity against certain strains of Gram-positive and Gram-negative bacteria, but were ineffective against B. subtilis, P. aeruginosa, P. putida and the eukaryotic microorganism C. albicans. Strains of Gram-positive bacteria were more sensitive to the action of all three types of plant oils. The most sensitive strain was M. luteus ATCC 4698, the size of which zones of no growth exceeded 16 mm under the influence of all tested oils. Pumpkin seeds oil was more effective against sensitive test strains of indicator microorganisms. Conclusions. Plant oils obtained by cold pressing from pumpkin seeds, grape seeds and sea-buckthorn fruits showed variable antimicrobial activity, which was better in pumpkin seeds oil. K. rhizophila DSM 3480 and M. luteus ATCC 4698 strains were the most sensitive to its influence, the sizes of the zones of no growth were 16.5 ± 0.1 mm and 16.3 ± 0.2 mm, respectively. Further researches are necessary to determine the chemical composition and quantitative assessment of the bioactive compounds of these oils, as well as the mechanisms of their action on the cells of microorganisms.

Synthesis, characterization, DNA/BSA-binding affinity and biological activity of dinuclear palladium(II) complexes with aromatic N-heterocyclic bridging ligand

Dinuclear palladium(II) complexes, [{Pd(en)Cl}2(μ-L)](NO3)2 (L is bridging ligand pirazine (Pd1), pyrimidine (Pd2), pyridazine (Pd3), phenazine (Pd4) and en is ethylenediamine), were synthesized and characterized. The interactions of the synthesized palladium(II) complexes with biomolecules such as DNA and BSA were studied using UV–Vis spectroscopy and fluorescence spectroscopy. Analysis of tumoricidal activity of investigated complexes, tested on several tumor cell lines of human and mouse origin, revealed that Pd1 and Pd2 exhibited weak cytotoxic potential at lower concentrations. However, Pd3 showed higher cytotoxicity effects on the human MDA-MB 468 breast carcinoma and A375 melanoma cell lines, while Pd4 exhibited tumoricidal potential against MDA-MB 468 cells and A549 human lung adenocarcinoma cells. Interestingly, A375 human melanoma cells were highly sensitive to Pd4 treatment similarly to the effect of cisplatin. Further, the antimicrobial effects of tested compounds were evaluated using different species of Gram-positive and Gram-negative bacteria, as well as yeasts. Pd1–Pd4 showed variable antimicrobial activity depending on the microorganism species. Among tested complexes, Pd4 exhibited the highest antimicrobial activity. The obtained data suggest that palladium(II) complexes might be further investigated as potential antitumor and antimicrobial agents.

Antimicrobial Activity of Three Italian Strains of Morchella esculenta (Ascomycota).

Three genetically identified and morphologically characterized strains (MesAQ2-C, MesAQ6-2 and MesFI2-3) of the culinary-medicinal ascomycete mushroom Morchella esculenta (L.) Pers. collected in central-north Italy have been studied for their antifungal and antibacterial activities. The obtained data showed that mycelium of M. esculenta possess variable antimicrobial activity against four test fungi (Chrysosporium keratinophilum, Microsporum gypseum, Trichophyton terrestre, Penicillium griseofulvum), as well as one Gram positive (Staphylococcus aureus) and three Gram negative (Escherichia coli, Salmonella typhimurium, Pseudomonas aeruginosa) test bacteria potentially pathogenic for humans and animals. Up to 20.4% of inhibition of the average mycelial growth rate (GRavr) of test fungi in dual culture experiment was detected. The samples of cultural liquid (CL) and mycelial extract (ME) obtained by static cultivation of M. esculenta strains showed up to 13.9 and 23.0% of GRavr inhibition of test fungi, respectively. Similarly, the inhibition of the bacterial colonies by CL and ME samples was 34.1 and 32.3%, respectively in comparison with the control with streptomycin indicating almost equal secretion of both intra- and extracellular antimicrobial compounds by M. esculenta mycelium. As a producer of antimicrobial compounds among tested M. esculenta strains, MesAQ2-C was the most effective. It may be considered for further myco-pharmacological research to develop mushroom-based antimicrobial biotech products with biomedical significance.

In vitro evaluation of probiotic properties of yeasts and lactic acid bacteria isolated from ersho samples collected from different parts of Ethiopia

ABSTRACT Ersho is an undefined starter culture used for Ethiopian injera production, and it is a good source of yeasts and lactic acid bacteria (LAB). However, few researchers have been done on the characterization of yeasts and LAB from ersho samples as a source of probiotics. The objective of the current work was to isolate and screen yeasts and LAB from ersho samples and in vitro characterization of their probiotic properties. An experimental research design was used. A total of 55 ersho samples were collected. Based on the ersho samples, 220 yeast colonies and 220 LAB colonies were isolated and purified. For the probiotic characterization, three yeasts (4A, 14D, 54A) and three LAB (1A, 13E, and 55A) were chosen. The isolates 4A, 14D, 54A, 1A, 13E, and 55A were identified as Saccharomyces cerevisiae KRSAN1, Saccharomyces cerevisiae JYC2577, Kazachstania humilis, Enterococcus lactis, Lactobacillus paracasei, and Lactobacillus species, respectively. All the isolates showed positive probiotic characteristics. They had very good acid resistance (percentage survival > 80%), high bile salt resistance (percentage survival > 140%), high cell surface hydrophobicity (>40%), high levels of auto-aggregation (>40%), variable co-aggregation with pathogens (ranged between 42% and 72%), variable antimicrobial activity (clear halo zone ranged from 4.0 to 31 mm), and variable antibiotic resistance responses. The results indicated that the ersho samples can be used as yeast and LAB sources for developing food and probiotic starter cultures.

Variation in Antimicrobial Activity and Seed Storage Proteins in Three Species of the Medicinal Plant Alstonia

The family Apocynaceae comprises three species of the substantially important Alstonia plant, viz., A. scholaris, A. venenata, and A. macrophylla. The investigation of proteins contained within seeds, that has the potential to provide both precise details and a structural basis for characterizing diversity. The utilization of an electrophoretic technique for protein analysis has been observed in recent scholarly investigations. This implies that certain protein bands exhibit variability, with their presence or absence being detected across different seed arrangement levels in the gel. Furthermore, this implies that the protein bands have been segregated into distinct categories. A study was conducted to analyze the seed storage protein profiles of three distinct Alstonia species through the application of sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The resolution of the seed storage protein of the Alstonia species using 15% SDS was found to alter the banding pattern of the polyacrylamide gel. The SDS-PAGE analysis revealed differential up regulation of proteins across distinct bands. Throughout the examination, it was determined that the three aforementioned species exhibited acommon band, in addition to a protein with a molecular weight of 34 kDa. The number of protein bands attached to A. venenata was the highest (ten bands), while the number of protein bands that adhered to A. scholaris was the lowest (five bands). Further, powdered leaves of A. scholaris, A. venenata, and A. macrophylla were investigated for antibacterial and the results, A. macrophylla leaf powder is most effective against Staphylococcus aureus, followed by A. venenata and A. scholaris at 1 μg/ mL. In addition, the findings support the inference that the A. scholaris leaf powder effectively inhibited the growth of Aspergillus niger. A. venenata and A. macrophylla, both at 1μg/mL, are, nonetheless, also effective against A. niger. A. macrophylla has the largest zone of inhibition (11.5 mm) against A. niger.

Biosynthesis, Spectrophotometric Follow-Up, Characterization, and Variable Antimicrobial Activities of Ag Nanoparticles Prepared by Edible Macrofungi.

The biosynthesis of silver nanoparticles (Ag NPs) could play a significant role in the development of commercial antimicrobials. Herein, the biosynthesis of Ag NPs was studied using the edible mushroom Pleurotus floridanus, and following its formation, spectrophotometry was used to detect the best mushroom content, pH, temperature, and silver concentration. After that, the morphology was described via transmission electron microscopy (TEM), and nanoscale-size particles were found ranging from 11 to 13 nm. The best conditions of Ag content and pH were found at 1.0 mM and 11.0, respectively. In addition, the best mushroom extract concentration was found at 30 g/L. According to XRD analysis, the crystal structure of the formed amorphous Ag NPs is cubic with a space group of fm-3m and a space group number of 225. After that, the function groups at the surface of the prepared Ag NPs were studied via FTIR analysis, which indicated the presence of C=O, C-H, and O-H groups. These groups could indicate the presence of mushroom traces in the Ag NPs, which was confirmed via the amorphous characteristics of Ag NPs from the XRD analysis. The prepared Ag NPs have a high impact against different microorganisms, which could be attributed to the ability of Ag NPs to penetrate the cell bacterial wall.

Comparison of the quantity and antimicrobial activity of host defence peptides in ear canals between healthy and atopic dogs: A preliminary study.

Host defence peptides (HDPs) are involved in cutaneous immune defence. The secretion of HDPs in the ears of healthy normal and noninfected atopic dogs has not been measured. The aim of this study was to quantify the concentrations of β-defensins (cBD3)-like and cathelicidin (cCath) HDPs in ears of healthy and atopic dogs without infectious otitis, additionally to evaluate the antimicrobial effect of the HDPs obtained. Ten healthy and 20 atopic dogs with mild inflammatory, noninfectious otitis were included. Absence of infection was determined by cytological evaluation, and the severity of clinical signs, if present, was assessed by a previously validated score (Otitis Externa Scoring System for Clinical Study, OTIS-3). The left ear canal of each dog was rinsed with 2 mL of sodium phosphate buffer. The solution obtained was analysed by enzyme-linked immunosorbent assay to quantify HDPs. Additionally, aural secretions were incubated with two concentrations (5 × 105 and 5 × 104 colony-forming units/mL) of Staphylococcus pseudintermedius and the bacterial density measured after 24 h of incubation. Data were statistically analysed. Significance was set as p ≤ 0.05. There was a significantly lower concentration of HDPs from atopic ears when compared with those from normal healthy dogs (cBD3-like: p = 0.0007; cCath: p = 0.049). There was minimal to variable antimicrobial activity in the aural secretions of both groups. This study showed, for the first time, that the ear canals of atopic dogs with mild noninfectious otitis contain a lower concentration of cBD3-like and cCath HDPs than those of healthy dogs with normal ears. A consistent antimicrobial activity was not present in the aural secretions from either group.

Antimicrobial Activity of Some Plant Extracts and Their Applications in Homemade Tomato Paste and Pasteurized Cow Milk as Natural Preservatives

Synthetic chemical preservatives are widely used in the food industry to delay the deterioration caused by microbial growth, enzyme activities and oxidation reactions. The last few decades have witnessed marked interest in finding natural food preservatives due to the potential health damage of synthetic preservatives; consumers have become skeptical of consuming foods containing these additives. Polyphenols used as natural preservatives that can be extracted from fruits, vegetables, herbs and spices provide the best alternative for partial or complete replacement of their synthetic analogues. The present study’s emphasis was on employing different plant extracts to be efficiently used as antimicrobial agents for developing replacements for the synthetic chemical additives in food products. The study also investigated the antimicrobial potentialities of five medicinal plants, widely used in Egypt (sumac, tamarind, rosemary, roselle and lemon) against six microbial markers (E. coli, P. aeruginosae, B. subtilis, S. aureus, Penicillium sp. and A. niger.). Sumac extracts showed the best activity against all tested microorganisms, producing the widest inhibition zones ranging from 14 to 45 mm, followed by tamarind and roselle extracts, with inhibition zones ranging from 8–36 and 8–34 mm, respectively. On the other hand, extracts of rosemary and lemon showed variable antimicrobial activity. All extracts from all tested plants were less active against fungal species than bacterial species. In all cases, the organic extracts (80% methanol, 80% ethanol) showed the same or greater activity than the aqueous extracts. In addition, the methanolic extracts showed the strongest and broadest spectrum. The most sensitive strain to plant extracts was B. subtilis, while the most resistant strain was P. aeruginosae. The MIC and MBC or MFC values of methanolic extracts were assayed using the broth dilution method. Sumac extract showed the best activity against all tested microorganisms with the lowest values of MIC and MBC or MFC (from 0.260 to 0.877 and 0.310 to 1.316 mg/mL, respectively, for bacteria, and from 1.975 to 2.5 and 2.5 to 4.444 mg/mL, respectively, for fungi). Interestingly, the tested extracts inhibited microbial growth in tomato paste and pasteurized cow milk for a long storage period (increase shelf life) as compared to the control samples. In conclusion, herbal and spice extracts could be successfully applied as natural antimicrobials for the elimination of food borne microbes and pathogen growth.

In-vitro determination of antimicrobial activities of Eruca sativa seed oil against antibiotic-resistant gram-negative clinical isolates from neonates: a future prospect

BackgroundThe aim of this study is investigate the antimicrobial effect of plant oils against bacterial strains isolated from neonatal asymptomatic bacteriuria (ABU) and to evaluate the antiseptic effect of the most potent one.MethodsThe antimicrobial effect of 17 plant oils were tested against 15- gram-negative bacterial strains recovered from cases of neonatal ABU (11 Escherichia. coli, 3 Klebsiella pneumonia, and 1 Pseudomonas aeruginosa) using the agar well diffusion method. The micro-dilution method was performed to investigate the minimum inhibitory concentrations (MIC) and the minimum bactericidal concentrations (MBC) in concentrations ranging from 1.95 μg/ml to 500 μg/ml. The evaluation of the antiseptic activity of the Eruca sativa (arugula) seed oil was investigated using time-kill assay in concentrations ranging from 50 μg/ml to 0.195 μg/ml.ResultsAll tested oils showed variable antimicrobial activities against the tested strains. Arugula, wheat germ, cinnamon, parsley, dill, and onion oils were the most active oils. Among them, arugula oil was the most active oil with MIC50 and MIC90 were 3.9 μg/ml and 31.3 μg/ml respectively. MBC50 and MBC90 of arugula oil were 15.6 μg/ml and 125μg/ml respectively. The time-kill assay of arugula oil indicated that a concentration of 100 μg/ml completely killed nine of the tested strains after 10 min and reduced the CFU/ml of the rest of the strains by 3 log10 at the same time interval.ConclusionArugula seed oil could be a potentially used as an antiseptic especially for neonates.

Effect of metal cations on antimicrobial activity and compartmentalization of silver in Shewanella oneidensis MR-1 upon exposure to silver ions

Silver is an antimicrobial agent that is used extensively in consumer products, such as fabrics and humidifiers. Silver ion (Ag+) uptake in bacteria represents a crucial phase of antimicrobial activity. However, the uptake mechanism of Ag+ in bacteria remains largely unknown. The genus Shewanella drives many geochemical processes of nutrients and pollutants in soils. In the present study, Ag+ uptake by Shewanella oneidensis MR-1 was first investigated in a laboratory in defined anaerobic, oligotrophic, and inorganic media with or without cations (potassium ions [K+], magnesium ions [Mg2+], and zinc ions [Zn2+]). Our results revealed variations in antimicrobial activity of Ag+ in the presence of Mg2+ and Zn2+. First, Mg2+ significantly decreased antimicrobial activity of Ag+ in S. oneidensis MR-1 by inhibiting cellular Ag+ uptake when compared with K+. The results were consistent with that of Co2+ (Mg2+ channel blocker) decreased Ag+ uptake by S. oneidensis MR-1. Moreover, Mg2+ promoted riboflavin secretion and facilitated the formation of metallic Ag nanoparticles on bacterial surfaces, which was beneficial for extracellular electron transfer and consequently reduced antibacterial activity of Ag+. Second, Zn2+ increased the antimicrobial activity of Ag+ in S. oneidensis MR-1, although the effect on Ag+ uptake was minimal. A synergistic interaction between Zn2+ and Ag+ led to an increase in dead cells and decreased ferrihydrite reduction capacity. The findings suggest that Mg2+ could reduce the environmental risk of Ag+ to soil bacteria, while Zn2+ should be of particular concern due to its synergistic antimicrobial effect on bacteria.

Antimicrobial Activity of Polyphenolic Compounds

Introduction. The emergence of new strains of microorganisms with multidrug resistance (MDR) is one of the most pressing problems of modern medicine. Currently, to combat MDR, active attempts are being made to obtain new biologically active substances of natural (microbial, plant, animal) origin. Earlier, 32 individual compounds were isolated by the authors from the aerial part of Iris laclea Pall., Rubus chameamorus L. leaves, Empetrum nigrum L. shoots, Ononis arvensis L. aerial part and Solidago canadensis L. aerial part, and 2 more compounds were synthesized according to previously published methods. The study of the antimicrobial activity of compounds of these classes is an urgent problem for finding potential agents for combating MDR. Aim. Studying of the antimicrobial activity of the isolated and synthesized substances in an individual form against Staphylococcus aureus , Escherichia coli and Candida albicans . Materials and methods. To test the antimicrobial activity, substances of 34 compounds were used, which were obtained as a result of previous research, the structure of which were established using NMR spectroscopy and high-resolution mass spectrometry. The antifungal and antibacterial activity of the compounds were determined through the micromethod of two-fold serial dilutions in liquid nutrient medium in 96-well plates in duplicate. Screening for antimicrobial activity was carried out against reference (type) strains of Staphylococcus aureus ATCC 6538-P, Escherichia coli ATCC 25922, Candida albicans NCTC 885-653. Results and discussion. In the group of flavonoids and O-, C-glycosides, the antifungal activity of all studied compounds did not differ significantly, but it should be noted that the antibacterial activity of apigenin C-glycosides and isoflavonoid O-glycosides was slightly greater in comparison to O-glycosides of flavonols. The greatest antimicrobial activity among the group of chalcones was shown directly by the chalcones themselves – chalcone, 2’, 4’-dihydroxychalcone, and 2’-hydroxy-4’-methoxychalcone. Among the dihydrochalcones, the highest antimicrobial activity was found for 2‘, 4’-dihydroxyhydrochalcone, which was comparable in magnitude to the antimicrobial activity of the chalcones themselves. An interesting feature of dihydrochalcones is that methylation of phenolic hydroxyl groups in the 2‘ and 4’ positions decreases the antimicrobial activity. The antimicrobial activity of 9,10-dihydrophenanthrenes, as in the case of dihydrochalcones, depended on the number of methoxy groups in the molecule. The lowest MIC values were exhibited by 4,7-dihydroxy-2,3-dimethoxy-9,10-dihydrophenanthrene containing only two methoxy groups. For bibenzyls, an inverse dependence of antimicrobial activity on the number of methoxy groups was observed – the best activity among bibenzyls against the studied strains was shown by 1-(3-hydroxyphenyl)-2-(3-hydroxy-4,5-dimethoxyphenyl)ethane, which contains two methoxy groups in its structure. Conclusion. Polyphenolic secondary metabolites of plant origin belonging to the studied groups: flavonoids and O-, C-glycosides, chalcones, 9,10-dihydrophenanthrenes and bibenzyls did not show significant antimicrobial activity against the studied strains of microorganisms – S. aureus (6538 EP ATCC), E. coli (25922 ATCC) and C. albicans (885-653 NCTC). Despite this fact, a certain variation in antimicrobial activity was revealed depending on the structure of the tested substances.

Antimicrobial Activity of Green Silver Nanoparticles Synthesized by Different Extracts from the Leaves of Saudi Palm Tree (Phoenix Dactylifera L.).

The Arabian desert is rich in different species of medicinal plants, which approved variable antimicrobial activities. Phoenix dactylifera L. is one of the medical trees rich in phenolic acids and flavonoids. The current study aimed to assess the antibacterial and antifungal properties of the silver nanoparticles (AgNPs) green-synthesized by two preparations (ethanolic and water extracts) from palm leaves. The characteristics of the produced AgNPs were tested by UV-visible spectroscopy and Transmitted Electron Microscopy (TEM). The antifungal activity of Phoenix dactylifera L. was tested against different species of Candida. Moreover, its antibacterial activity was evaluated against two Gram-positive and two Gram-negative strains. The results showed that AgNPs had a spherical larger shape than the crude extracts. AgNPs, from both preparations, had significant antimicrobial effects. The water extract had slightly higher antimicrobial activity than the ethanolic extract, as it induced more inhibitory effects against all species. That suggests the possible use of palm leaf extracts against different pathogenic bacteria and fungi instead of chemical compounds, which had economic and health benefits.

Anticancer and Antimicrobial Activity of Red Sea Seaweeds Extracts-Mediated Gold Nanoparticles

Biosynthesis of gold nanoparticles (AuNPs) is emerging as a better alternative to traditional chemical-based techniques. During this study, extracts of different marine algae species Ulva rigida (green algae), Cystoseira myrica (brown Algae), and Gracilaria foliifera (red Algae) were utilized as reducing and capping agents to synthesize AuNPs. AuNPs capped by U. rigida, C. myrica, and G. foliifera were confirmed by the appearance of surface plasmonic bands at 528, 540, and 543 nm, respectively. Transmission electron microscopy revealed mostly spherical shapes of AuNPs having a size of about 9 nm, 11 nm, and 13 nm for C. myrica, and G. foliifera extracts, respectively. Fourier transform-infrared spectroscopy (FTIR) illustrated the major chemical constituents of U. rigida, C. myrica, and G. foliifera. LC50 values of the biosynthesized AuNPs against Artemia salina nauplii were calculated at a range of concentrations (5-188 μg ml−1) after 16 to 24h. AuNPs concentration-dependent lethality was noted and U. rigida extracts-mediated AuNPs presented the lowest cytotoxicity. The biosynthesized AuNPs exhibited significant anticancer activity (86.83%) against MCF-7 cell lines (human breast adenocarcinoma cell lines) at 188 µg/ml concentration. G. foliifera demonstrated the highest anticancer value (92.13%) followed by C. myrica (89.82%), and U. rigida (86.83%), respectively. The AuNPs synthesized by different algal extracts showed variable antimicrobial activity against the tested pathogenic microorganisms. AuNPs of U. rigida extracts showed significant antimicrobial activity against dermatophytic fungi Trichosporon cataneum (30 mm) followed by Trichophyton mantigrophytes (25 mm). Furthermore, it also exhibited mild activity against Escherichia coli (17 mm), Cryptococcus neoformans (15 mm), Candida albicans (13 mm), and Staphylococcus aureus (11mm), respectively whereas no effects were observed against Bacillus cereus. To conclude, AuNPs can be effectively synthesized by marine algal species, and particularly U. rigida extracts could be effective reducing agents for the green AuNPs synthesis. These AuNPs could potentially serve as efficient alternative anticancer agents against human breast adenocarcinoma and anti-dermatophytes associated with skin infections.

Phytochemical Analysis, Antimicrobial and Antioxidant Properties of Thymus zygis L. and Thymus willdenowii Boiss. Essential Oils.

Essential oils (EOs) are chemical products produced by odoriferous glands from a variety of plants. These essential oils have many health benefits: antiseptic, anti-inflammatory and antimicrobial activities. So due to these medicinal properties, the present study was designed to analyze essential oils of Thymus zygis L. and Thymus willdenowii Boiss. for their chemical composition and biological activities. These two thyme species were collected from the region of Ifrane, Middle Atlas of Morocco. The EO was obtained by hydrodistillation, and the yields were 5.25% for T. zygis and 3.00% for T. willdenowii. The chemical composition of the EOs was analyzed by gas chromatography coupled with mass spectrometry (GC-MS), and the results showed that T. zygis EO is dominated by carvacrol (52.5%), o-cymene (23.14%), and thymol (9.68%), while the EO of T. willdenowii contains germacrene D (16.51%), carvacrol (16.19%), and geranyl acetate (8.35%) as major compounds. The antioxidant activity assessed by Diphenylpicrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays revealed that both EOs have excellent antioxidant activities; by DPPH it resulted in IC50 = 6.13 ± 0.11 for T. zygis and 6.78 ± 0.3 µg/mL for T. willdenowii, while the one by FRAP yielded EC50 = 2.46 ± 0.01 (T. zygis) and 5.17 ± 0.2 (T. willdenowii) µg/mL. The antimicrobial activity of the two essential oils was evaluated against six bacterial strains and five fungal strains by the disk diffusion method to determine the Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC) and Minimum Fungicidal Concentration (MFC). The EOs revealed variable antimicrobial activities against the different tested microbial strains and showed strong antimicrobial activities, even against strains known as multi-resistant to antibiotics (Acinetobacter baumannii) at low concentrations (2 µL/mL). T. zygis EO showed the most powerful activity against all the studied bacteria, while that of T. willdenowii recorded moderate activity when tested against Shigella dysenteriae and Salmonella Typhi. With inhibition diameters that vary between 75 mm and 84 mm for concentrations of 2 µL/mL up to 12 µL/mL, S. aureus was shown to be the most sensitive to T. zygis EO. For the antifungal activity test, T. zygis EO showed the best inhibition diameters compared to T. willdenowii EO. These results showed that T. zygis EO has more powerful antioxidant and antimicrobial activities than T. willdenowii EO, therefore, we deduce that thyme EOs are excellent antioxidants, they have strong antimicrobial properties, and may in the future represent new sources of natural antiseptics that can be used in pharmaceutical and food industry.

A new iridoid skeleton from Galium asparagifolium and biological activity studies

This study identifies the detailed phytochemical content and biological effects of Galium asparagifolium, for the first time and gained one new iridoid aglycone (1), seven known iridoid glycosides (2–8), two flavonoids (9–10), and one carbohydrate derivative (11) to the literature. The 1D-, 2D- NMR analyses and ESI-Mass allowed us to resolve the structure of new compound as (1S,4aS,​​8aS)-pyrano[4,​3-​c]​pyran-1,​4a,​5,​7,​8,​8a-​hexahydro-​1-​hydroxy-​3-(​2-​hydroxyethyl)-​8-​methyl-8-​carboxylic acid namely galiumic acid. The compounds 1–11 and extracts from G. asparagifolium were investigated in terms of cytotoxic activity by MTT assay, antioxidant activity by DPPH method and antimicrobial activity by DDT and BMM methods. While all compounds and extracts did not show remarkable cytotoxicity, they had variable antimicrobial activities for a variety of gram-positive/gram-negative bacteria and yeast strains. Besides that, most of the compounds showed antioxidant effect with a wide range of DPPH% inhibition values. The structure of the new compound was also elucidated by some computational studies.

The Chemical Profiling of Essential Oils from Different Tissues of Cinnamomum camphora L. and Their Antimicrobial Activities.

Cinnamomum camphora L. is grown as an ornamental plant, used as raw material for furniture, as a source of camphor, and its essential oil can be used as an important source for perfume as well as alternative medicine. A comparative investigation of essential oil compositions and antimicrobial activities of different tissues of C. camphora was carried out. The essential oils were extracted by hydrodistillation with a Clevenger apparatus and their compositions were evaluated through gas chromatography-mass spectrometry (GC-MS), enantiomeric composition by chiral GC-MS, and antimicrobial properties were assayed by measuring minimum inhibitory concentrations (MICs). Different plant tissues had different extraction yields, with the leaf having the highest yield. GC-MS analysis revealed the presence of 18, 75, 87, 67, 67, and 74 compounds in leaf, branch, wood, root, leaf/branch, and leaf/branch/wood, respectively. The significance of combining tissues is to enable extraction of commercial quality essential oils without the need to separate them. The oxygenated monoterpene camphor was the major component in all tissues of C. camphora except for safrole in the root. With chiral GC-MS, the enantiomeric distributions of 12, 12, 13, 14, and 14 chiral compounds in branch, wood, root, leaf/branch, and leaf/branch/wood, respectively, were determined. The variation in composition and enantiomeric distribution in the different tissues of C. camphora may be attributed to the different defense requirements of these tissues. The wood essential oil showed effective antibacterial activity against Serratia marcescens with an MIC of 39.1 μg/mL. Similarly, the mixture of leaf/branch/wood essential oils displayed good antifungal activity against Aspergillus niger and Aspergillus fumigatus while the leaf essential oil was notably active against Trichophyton rubrum. C. camphora essential oils showed variable antimicrobial activities against dermal and pulmonary-borne microbes.

In vitro evaluation of the antimicrobial activity and diffusion capacity of solutions used for canine ear cleaning

Otitis is a common condition among dogs and requires appropriate treatment. Given the importance of the otitis externa and the use of products to combat this condition, this study evaluated the in vitro antimicrobial abilities of six commercial ear cleaners solutions (EC1 to EC6) and solutions of 3% boric acid, 3% lactic acid, 0.11% salicylic acid, 0.5% chlorhexidine, and 3% propylene glycol against Staphylococcus spp., Pseudomonas spp., Proteus spp., and Malassezia spp. The in vitro diffusion capacity in synthetic cerumen was also assessed. Dogs with clinical signs of otitis externa were selected and samples were collected from the external ear canals. The microbiological study was performed to identify the microorganisms from samples collected and the microorganisms isolated were used in the study. One ceruminolytic for human use and five commercial solutions used for canine ear cleaning were selected based on the diversity of the components used in each formula. The results show a variation of antimicrobial activity and diffusion capacity ear cleaners and its compounds. Lactic acid, chlorhexidine, EC1, EC2, EC4, and EC5 showed the best results for microbiological growth inhibition; boric acid, salicylic acid, propylene glycol and EC6 had little or no effect on microorganism growth. The ECs tested demonstrated diffusion capacity using the SSC. EC1 was the solution with the most significant responses, both as an antimicrobial agent and with regards to diffusion capacity. Among the commercial veterinary products tested, EC4 was found to have the best results.

Isolation and characterization of aroma producing lactic acid bacteria from artisanal white cheese for multifunctional properties

The aim of this study is to isolate and characterize potential aroma producing lactic acid bacteria with some probiotic properties from artisanal cheese environment. For this purpose, 40 of lactic acid bacteria isolates were obtained from traditionally produced White cheese samples. They were preliminary characterized in Enterococcus genus by morphological, physiological, biochemical tools. Technological properties such as milk acidifying, lipolytic and proteolytic activities were also screened. Most of them were good acid producers. Aroma producing ability was determined by diacetyl production and among 40 isolates, 18 of them could produce this compound. DNA isolation and 16 S rRNA ribosomal gene sequence analysis of selected isolates indicated that they were identified as E. faecium, E. faecalis and E. durans. Aroma producers were screened for their probiotic characteristics and they showed variable acid tolerance, hydrophobicity, auto-aggregation, antimicrobial activity and antibiotic sensitivity. All of them tolerated bile salt. In conclusion, particularly two isolate, MD 30 and MD 38 identified as E. faecium were found to be the most promising bacteria due to both technological and probiotic traits.

Seasonal Variation in Antimicrobial Activity of Crude Extracts of Psammaplysilla sp. 1 from Phillips Reef, South Africa.

Marine invertebrates constitute a diverse group of marine organisms beneficial to humanity due to their therapeutic significance. The marine sponge species Psammaplysilla sp. 1 was collected from Philips Reef, South Africa, over a four-season period and assayed for antimicrobial potential. The physicochemical parameters of the collection site were also recorded. The sponge crude extracts' antimicrobial activity was evaluated using an agar well diffusion assay against 5 pathogens. Phytochemical screening was conducted to identify the presence of 7 critical phytochemical groups. During the four seasons, the mean water temperature was 17.35°C ± 2.06, with autumn recording the highest (20°C) temperature. Antifungal activity was observed by Psammaplysilla sp. 1 (30 mm) against C. albicans, and this was higher than that showed by standard drugs ICZ-10 µg (15 ± 0.1 mm), FLU-15 µg (21 ± 0.2 mm), and VCZ-5 µg (17 ± 0.1 mm), respectively. Similar bioactivities were observed seasonally with Psammaplysilla sp. 1 (22 mm and 24 mm) during autumn and spring, respectively, against C. difficile while only crude extracts collected in spring showed bioactivity against C. albicans. Psammaplysilla sp. crude extracts showed broad-spectrum bioactivity against all test pathogens. DCM : ME crude extracts tested positive for the presence of 2/7 of the phytochemicals (terpenoids and flavonoids). GC-MS revealed several previously reported biologically active compounds such bicyclo[4.2.0]octa-1,3,5-trien-7-ol and phenol, 2,6-dibromo, some of which have been found in plants. This study revealed that sponge bioactivity is dependent on the season and further validated the antimicrobial potential of South African marine sponges.

Synergistic Effect of Plant Extracts on Endodontic Pathogens Isolated from Teeth with Root Canal Treatment Failure: An In Vitro Study.

Background and objectives: This study aimed to evaluate the synergistic antimicrobial activity of extracts obtained from Salvadora persica (Miswak), Commiphora molmol (myrrh) and Azadirachta indica (neem) in combination with commercially available antimicrobial agents: penicillin, tetracycline, ofloxacin and fluconazole on endodontic pathogens such as Enterococcus faecalis, Streptococcus mitis, Actinomyces naeslundii and Candida albicans. Materials and Methods: Microbiological samples from the root canals of the teeth undergoing retreatment were taken using sterile paper points kept at full length in the canal for 30 s. The disc diffusion method was used to check the susceptibility of microbes to the plant extracts and antimicrobials by measuring the diameter of the inhibition zones. Against the microbes, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)/minimum fungicidal concentration (MFC) of the plant extracts were assessed. The fractional inhibitory concentration index (FICI) was used to estimate the synergistic effect of plant extracts combined with antimicrobials against the resistant endodontic microbes. Results: The findings clearly indicate the effectiveness of all the three plant extracts, Commiphora molmol, Azadirachta indica, Salvadora persica, against all the experimental pathogenic microorganisms except for the ineffectiveness of Azadirachta indica, Salvadora persica against Candida albicans. Maximum antimicrobial activity was displayed by Azadirachta indica against Enterococcus faecalis (MIC = 0.09 ± 1.2 mg/mL, MBC = 0.78 ± 1.25 mg/mL) and the minimum antimicrobial activity was displayed by Commiphora molmol against Actinomyces naeslundii (MIC = 12.5 ± 3.25 mg/mL, MBC = 100 ± 3.75 mg/mL). The best synergy was displayed by Commiphora molmol with fluconazole against Candida albicans (FICI = 0.45). Conclusions: The current study delineates the variable antimicrobial activity of plant extracts against the experimental endodontic pathogenic microorganisms. Plant extracts in conjunction with various antimicrobials can be valuable aids in combating relatively resistant endodontic microorganisms that have been the cause of worry in recent years, leading to failure even in treatment procedures following all required protocols.