Antibacterial Activity Of Oil Research Articles

"Essential oil Composition, Antioxidant and Antibacterial Activities of Jatropha tanjorensis (Euphorbiaceae)"

Background: Jatropha tanjorensis (Euphorbiaceae) leaves are traditionally used for the treatment of diabetes and also, possess antibacterial potential. The chemical composition, antioxidant and antibacterial activities of the oil were investigated. The essential oil (EO) was obtained by hydro-distillation method and characterised using gas chromatography-mass spectrometry (GC-MS). The antioxidant activity was investigated using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging technique and antibacterial activity of the volatile oil was evaluated against 6 strains of bacteria: Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Staphylococcus aureus, Bacillus subtilis and Salmonella typhi, using broth dilution method.

Chemical Characterization and Antibacterial Properties of Fontitrygon margarita (Günther, 1870) Liver Oil.

Objective The aim of this study was to determine the chemical characteristics and antibacterial activity of Fontitrygon margarita liver oil against the bacteria responsible for food poisoning. Methods Oils were extracted from F. margarita liver using two methods (exudation and cooking-pressing) and analyses by Fourier transform infrared (FTIR) spectroscopy. Quality indexes were determined using standard methods and the fatty acid profile was carried out by gas chromatography with a flame ionization detector (GC-FID). Antibacterial activities of these oils, their emulsion, and their interactions with common antibiotics were evaluated by the broth microdilution method. Results Extraction yield was higher with cooking-pressing (16.90%) compared to exudation (14.49%). The quality indexes of both oils were conformed to Codex Alimentarius Standard. Thiobarbituric acid index was higher with exudation compared to cooking-pressing (3.20 ± 0.14 and 2.36 ± 0.14 μmol MDA/kg, respectively) while acid, iodine, peroxide, and anisidine values did not significantly vary with the extraction methods (2.15-2.30 mgKOH/g, 102.42-106.65 gI2/100 g, 3.34-3.57 meqO2/kg, and 2.85-3.32 respectively). FTIR analyses clearly show that the two spectra are similar (no differences in the frequency and absorbance of their bands). The fatty acid profile revealed that, regardless of the extraction methods, F. margarita oil is richer in monounsaturated (55.97-55.41%) followed by polyunsaturated (28.17-28.52%) and saturated fatty acids (15.86-16.07%). Moreover, these oils showed antibacterial activity on all the bacteria strains tested with MICs between 16 and 256 mg/ml. Regardless of the extraction methods, emulsions showed higher activity (6.25 ≤ MIC ≤25 mg/ml) compared to crude oils. Additionally, F. margarita liver oil potentiated the antibacterial activity of ciprofloxacin, tetracycline, gentamicin, amoxicillin, and chloramphenicol. Conclusion These results showed the effectiveness of Fontitrygon margarita liver oil against some bacteria responsible for food poisoning, thus demonstrating their antibacterial properties which could be due to their chemical composition.

Chemical Composition and Biological Activities of Eugenia caryophyllata Thunb Essential Oil

Aims: In this study the antibacterial and antioxidant activities of the essential oil of Eugenia caryophyllata were investigated.
 Study design: The study contains determination of the chemical composition of the essential oil of E. caryophyllata and the in vitro evaluation of the antibacterial and antioxidant activity of this oil.
 Place and Duration of Study: The study was carried out at the laboratory of research on local animal products of Ibn-Khaldoun University, Tiaret, Algeria during the period from December 2020 to March 2021.
 Methodology: The essential oil composition was characterized by gas chromatography/mass spectrophotometrical analyses. The antibacterial activity of this oil was tested against four pathogenic bacteria: Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 33862, Bacillus cereus ATCC 11778 by using disc diffusion method and agar incorporation method to determine the Minimum Inhibitory Concentration (MIC) of the tested oil. The antioxidant activity was evaluated by using DPPH radical scavenging, hydrogen peroxide scavenging assays and ferric reducing antioxidant power (FRAP) assay.
 Results: Our results have shown a greater antibacterial effect of E. caryophyllata essential oil against all the bacterial tested strains with inhibition zone diameters varied from 17.5 to 20.5 mm and minimal inhibition concentration (MIC) ranged between 0.8 μl / ml and 4.4 μl / ml, B. cereus and S. aureus are the most sensitive species with a MIC value of 0.8 μl / ml, however P. aeruginosa is the most resistant species with a MIC value of 4.4 μl / ml. The result of the antioxidant effect showed that the essential oil of E. caryophyllata is a powerful antioxidant that expresses a higher antioxidant activity than the standard antioxidants: gallic acid, vitamin C and BHT.
 Conclusion: The obtained results suggest that the essential oil of E. caryophyllata has a strong antibacterial and antioxidant effect and it may be an alternative natural source medicine to prevent and treat many diseases caused by pathogenic bacteria and oxidative stress.

Screening of antimicrobial, anti-quorum sensing activity and cytotoxicity of origanumoil against Gram-positive and Gram-negative bacteria

Introduction and Aim: Essential oils have been used from ancient times to treat different gram-positive and gram-negative bacterial-related infections. The study aims to screen the antibacterial, anti-quorum sensing activity of origanum oil against the common infection causing gram-negative and gram-positive bacteria.
 
 Material andMethods: The MIC (minimum inhibitory concentration) and antibacterial activity of origanum oil against the eight bacterial species, namely, Pseudomonas aeruginosa, Shigella flexneri, Salmonella enterica, Klebsiella pneumoniae, Streptococcus pneumonia, Streptococcus pyogenes, Staphylococcus aureus, and Enterococcus faecalis, was assessed by broth-dilution method and well diffusion method. The anti-quorum sensing activity was analyzed using bioreporter strain CV026 at sub-MIC concentrations, while the cytotoxicity of the origanum oil was analyzed using the SW480 cell line.
 
 Results: The oil's antibacterial activity was analyzed by measuring the clear inhibitory zone diameter, and maximum inhibitory zone of 36.66 mm zone against Staphylococcus aureus (Gram-positive) and 33.33 mm against Salmonella enterica (Gram-negative) of origanum oil was measured. And the minimum inhibitory zone of 16.66 mm zone of Enterococcus faecalis (Gram-positive) and 19.66 mm against Klebsiella pneumoniae (Gram-negative) of oil was noted. And the lowest MIC (0.1 mg/ml) of oilwas found against Streptococcus pneumonia. The oil significantly inhibited the violacein pigment production (30.29 %) at 0.02 mg/ml concentration (this oil concentration did not significantly affect the growth curve). The in vitro cytotoxicity assay shows that the oil inhibited the SW480 cells growth with increasing concentration.
 
 Conclusion: The origanum oil possesses antibacterial and anti-quorum sensing activity and can be used as an alternative for treating tested bacterial infection.

Antioxidant and Antibacterial Activities of Rosmarinus officinalis aqueous extract with Study of The Pharmaco-Toxicological Effect

The objective of the present work was to study the antioxidant activity of the aqueous extract and the antibacterial activity of the Rosmarinus officinalis aerial part essential oils. The Rosemary essential oil yield was equal to 1.47%. A great inhibitory power of Rosemary extract was revealed by the test of antioxidant activity (93.72%) by an IC50 of 16.95 µg/ml, which was superior to that of Butylated hydroxy anisol (BHA a synthetic antioxidant) (6.01µg/ml), and of ascorbic acid (1.27µg/ml). The essential oil antibacterial activity was evaluated against five bacterial strains, using the aromatogram method. Hence, a remarkable antibacterial activity was noted for Rosemary essential oil. Gram-positive bacteria were highly sensitive to the activity of this essential oil than the Gram-negative bacteria. Furthermore, pharmacological investigation of the plant aqueous extract revealed the plant had very important pharmaceutical effects (anti-inflammatory effect). The preliminary study of toxicity, according to oral voice, revealed that the Rosmarinus officinalis leaves were not toxic.

Essential oil from the rhizomes of the Saudi and Chinese Zingiber officinale cultivars: Comparison of chemical composition, antibacterial and molecular docking studies

BackgroundEssential oils have been known to possess useful biological activities and are widely used in aromatherapy owing to their peculiar aroma. The present study compared the essential oil composition isolated from the Chinese and Saudi ginger cultivars and determined their antimicrobial activity. MethodsThe volatile compounds were extracted by a hydrodistillation method and the composition was analysed by gas chromatography coupled with mass spectrometry (GC–MS). The antibacterial activity of oils was tested against the pathogenic Gram positive and Gram negative bacterial strains. Potential bioactivities were predicted with the help of Prediction of activity spectra for substances (PASS) software and the molecular docking studies on the mycobacterial protein were carried out using Pyrex with Vina wizard tool. ResultsA total of 43 and 30 volatile components were identified in the Chinese and Saudi varieties respectively. α–zingiberene in the Chinese and ar-curcumene in Saudi ginger oil were found to be the major volatile constituents. Ginger oil showed better antibacterial activity against Gram positive than Gram negative bacteria. Molecular docking studies showed ar-curcumene to have high binding affinity for the inhibition of bacterial protein. ConclusionThe presence of the biological active compounds such as α–zingiberene, ar-curcumene and β-sesquiphellandrene makes ginger essential oil a potential source of antimicrobialagents and as an additive/preservative in the food industry.

Sprayed Pickering emulsion with high antibacterial activity for wound healing

Effective treatment of wound injuries can prevent infections and promote healing. In this work, a sprayed Pickering emulsion composed of chitosan nanoparticles, tea tree oil and curcumin was formulated. The shear thinning behaviour allowed this Pickering emulsion to spray even with a high viscosity provided by the aqueous phase containing chitosan nanoparticles. Moreover, the Pickering emulsion could recover to the high viscosity after spraying onto the wounds, leading to the long residence time and intimate contact. In addition, the Pickering emulsion provided a carrier to encapsulate the tea tree oil, which caused sustained-release effects and further strengthened tea tree oil's antibacterial activity towards the Gram-negative Escherichia coli (E. coli), Gram-positive Staphylococcus aureus (S. aureus) and Gram-positive methicillin-resistant Staphylococcus aureus (MRSA). Besides, this multi-phase system offered a platform to load with hydrophobic curcumin, leading to better synergistic healing effects. Meanwhile, the Pickering emulsion avoided the irritation and toxicity related to surfactants, which was far safer than the classical emulsion especially when used in the defective skin. All these excellent properties endowed this sprayed Pickering emulsion with promising prospects for wound healing.

English

Coconut oil has profound health benefits but the high content of fatty acids is a concern to many consumers, as several processing methods have failed to produce oil with considerable change in fatty acid content. In this study, selected lactic acid bacteria including Lactobacillus plantarum, Lactobacillus pentosus, Leuconostoc mesenteroides and Enterococcus faecium were used to ferment coconut milk for production of virgin coconut oil. Fermentation was carried out for 48 h, after which the milk was processed through heating to produce coconut oil. Phytochemical content, proximate composition, determination of steroids and free fatty acid content of the oil and antibacterial activity of the oil against Staphylococcus aureus and Pseudomonas aeruginosa were carried out using standard analytical and laboratory procedures. The results obtained in this study indicate that the control and LAB fermented oil had similar composition of phytochemicals; steroids, anthraquinone and glycosides were present in all the virgin coconut oil produced; however, reduced moisture content, lower levels of ester and free fatty acid was observed and higher quantity of protein and ash were obtained for coconut oil fermented with LAB compared to the control. The virgin coconut oil produced using the starter culture also had higher acceptability (P<0.05) compared to the spontaneously fermented oil, as the milk fermented with Lactobacillus plantarum had the highest acceptability value. There was no significant difference in the antibacterial activity of the virgin coconut oil produced against the test organisms. This study indicates that free fatty acid and other undesirable constituents in coconut oil can be reduced using lactic acid bacteria as starter culture, hence, increasing the acceptability of the product.   Key words: Lactic acid bacteria, coconut milk, fermentation, coconut oil.  

Chemical Composition and Antibacterial Activity of the Essential Oils Extracted From 4 Medicinal Plants (Labiatae) of Kerman, Iran

Introduction: In many parts of the world, a rich tradition of using herbal medicine have been formed through history for treating many infectious diseases. Because of the side effects and the resistance that pathogenic microorganisms build against the antibiotics, much recent attention has been paid to extract biologically active compounds from plant species used in herbal medicine. The aim of this study was to determine the antibacterial activity of four medicinal plants’ essential oils from Labiatae family – Salvia macrosiphon, Rosmarinus officinalis, Dracocephalum polychaetum, and Origanum vulgare – on four pathogenic bacteria as well as identify their chemically active compound. Materials and Methods: The essential oil was extracted using hydro-distillation method. Then, analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS) and compounds were identified. The antibacterial activity of the oil was evaluated using agar disc diffusion method. Minimum inhibitory concentration (MIC) and Minimum Bactericidal Concentration (MBC) were determined in a broth dilution assay. Results: Most of the evaluated bacteria species were sensitive to the oils. MICs and MBCs showed that these 4 plants relatively had high efficacy against bacteria. More than 90% of the chemical contents of the oils was determined. Conclusions: The obtained results suggest and justify using the indigenous plants’ essential oils in traditional medicine as a treatment for microbial infections or as a preservative in food.

Biological activities of essential oils extracted from Thymus capitatus (Lamiaceae)

The present study aims to investigating, the chemical composition of the essential oil extracted from Thymus capitatus harvested in west, Algeria. It seeks the other objective to the determination of antioxidant, antibacterial and antifungal activities of oil in order to find new metabolite products, which are characterized by a biological activity. The investigations and research was carried out on the essential oil (EO) extracted from the dried leaves of Thymus Capitatus Lamiaceae that was harvested in the region of Tiart (West of Algeria). GC–MS analysis of EO is identified 22 components while thymol, carvacrol and γ-terpinene are the major components. The antioxidant activity of EO was evaluated by three methods: the DPPH test (2,2-diphenyl-1-1-picrirylhydrazil), the FRAP (Ferric reducing antioxidant power) and TAC (Total Antioxidant Capacity) test and compared with ascorbic acid, BHA (Butylated hydroxy anisole) and commercial thymol as standards. The results indicated that Thymus Capitatus oil showed higher antioxidant power in comparison with the standards with values of (0.61, 2.13 and 0.78) μg/mL for the DPPH, FRAP and TAC tests respectively. Also, the antibacterial activity of the oil was tested using the agar disc diffusion method, by determining the inhibition zone and the minimum inhibitory concentration (MIC). In this case, the results have shown a potential of the antibacterial activity than commercial antibiotics (Chloramphenicol, Cefoxitin, Gentamycin) against the tested strains, with MIC values of (29.44, 14.72, 14.72 and 7.36 μg/mL) for Staphylococcus aureus, S. typhi, E. coli and Streptococcus pneumoniae strains respectively. Furthermore, the antifungal study on the fungi of Cladosporium herbarum, Alternaria infectoria, Aspergillus Ochraceus, Trichophyton Sp reported significant results. The effectiveness of the oil showed that the essential oil has a fungicidal effect against the strains Cladosporium herbarum, Alternaria infectoria and a fungistatic effect against strains Aspergillus ochraceus and Trichophyton rubrum. The research outcomes clearly demonstrate that the essential oils of thymus capitatus can present an interesting alternative naturel which can be useful for food preservation and pharmaceutical treatment.

Essential oil antibacterial activity against methicillin-resistant and -susceptible Staphylococcus aureus strains

Staphylococcus aureus is a pathogen causing infections that range from skin lesions to life threatening conditions. Methicillin resistance development in S. aureus strains represents a huge problem worldwide. The inhibition efficacy of twelve different essential oils (laurel, anise, oregano, basil, lavender, mint, rosemary, tea tree, bergamot, grapefruit, ginger and winter savory) and of the antibiotic Vancomycin was tested against S. aureus NCTC6571 and clinical isolates using paper disk diffusion assay and broth microdilution test methods. Forty-four S. aureus strains isolated from different human sample were characterized for antibiotic resistance and 41% of them were methicillin resistant. Among the twelve tested oils basil, oregano and savory showed stronger inhibition effect on S. aureus growth than Vancomycin. These results can be useful for the formulation of topical gel containing selected essential oils active against S. aureus strains.

Fatty Acid Composition, Physico-Chemical and Antibacterial Activities of Oil Extracted from Bitter-Cola (Garcinia kola)

Garcinia kola (Bitter cola) is a medicinal plant which is exclusively tropical in distribution. Traditionally, African medicine regards the plant in high esteem. Oil extract from Garcinia kola had a deep brown color percentage yield of 3.3522 ± 0.01, Specific gravity of 0.9158 ± 0.01, Refractive index of1.5400 ± 0.01 and Viscosity (30°C)(Pas/sec) of 74.4383 ± 0.02 as its physical parameters respectively. All the physical parameters observed were very high compared with normal convectional oil. The chemical parameters wereAcid value 17.3910 ± 0.20mg/g, Free fatty acid 1.2174 0.20mg/g, Iodine value 26.9028 0.10g/100g, Saponification value 33.6600 ± 0.2mmol/kg and Peroxide value 24.000 0.2mg/g respectively. The saponification value which is inversely proportional to the mean molecular weight of the glycerides in the oil was very low. The antibacterial activities were Klebsiellapneumonia 0.20 ± 0.01, Streptococcus cereus 0.60 0.01, Staphylococcus aureus0.50 ± 0.02 and Salmonella typhii 0.30 ± 0.01 respectively. The fatty acid composition of the oil were palmitic acid (C16:0) 22.3528 as the only highest saturated fatty acid, Oleic acid (C18:1) 26.2410 as the only highest monounsaturated fatty acid, Linoleic acid (C18; 2) 42.9273 and linolenic acid (C18: 3) as the only polyunsaturated fatty acids present.The oil extracted from this seed showed that the seed had a low yield and the oil is a non-drying oil and very viscous. It can be effectively used for variety of domestic and pharmaceutical applications for curative purpose and fatty acid composition of this oil, suggest some industrial potentials.

Antioxidant activity of essential oils from condiment plants and their effect on lactic cultures and pathogenic bacteria

ABSTRACT: Studies about preservative and antioxidant activity of essential oils have been encouraged in recent years, given their importance to food industry. The aim of the current study was to evaluate the antioxidant properties and antimicrobial activity of essential oils deriving from Syzygium aromaticum, Cymbopogon citratus and Lippia alba against lactic and pathogenic bacteria responsible for food-borne diseases. Essential oil antibacterial activity was assessed through disc diffusion and macrodilution tests conducted in a mixed lactic culture of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus (YF-L903) and of Escherichia coli (ATCC 8739), Staphylococcus aureus (ATCC 6538), Salmonella enterica (ATCC 6017) strains. Based on the chromatographic analysis results, the essential oils shown to be composed of eugenol (79.41%) which was the prevalent compound in S. aromaticum, geranial (31.89%), neral (24.52%) and β-myrcene (25.37%) in C. citratus, as well as of geranial (33.80%) and neral (25.63%) in L. alba. The observed antibacterial activity confirmed the dose-dependent effect of these three oils on all the assessed bacteria; there was halo inhibition at concentration 20μL mL-1. The essential oil of S. aromaticum presented better antioxidant activity, with IC50 equal to 5.76μg mL-1 and antioxidant activity index of 6.94, and it was considered strong (AAI>2.0) in comparison to the other evaluated oils. This essential oil also presented excellent antioxidant activity at concentrations lower than the one required to inhibit lactic cultures. Based in this outcome, the essential oil from S. aromaticum can be used as preservative agent in processed food whose formulation presents lactic cultures.

Phytochemical characterization of the Baccharis dracunculifolia DC (Asteraceae) essential oil and antibacterial activity evaluation

The present study had as its objective to evaluate the antibacterial and antibiotic modulatory activity of the Baccharis dracunculifolia (DC) essential oil (EOBD), a species commonly known as “Alecrim do campo”. The essential oil chemical composition analysis and the direct in vitro antibiotic activity evaluation, as well as in combination with the antibiotics Ampicillin, Gentamicin, and Norfloxacin against standard Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 9027, and Staphylococcus aureus ATCC 25923 strains, as well as E. coli 06, P. aeruginosa 24, and S. aureus 10 resistant strains, were performed. Gas chromatography-mass spectrometry (GC–MS) revealed the major terpenoids: Germacrene D (18.4%), (E)-Nerolidol (14.0%), Mustacone (11.2%), Spathulenol (11%), β-pinene (9.5%) and Bicyclogermacrene (8.4%). A direct B. dracunculifolia essential oil antibacterial activity against S. aureus 25923 with a MIC of 102 μg/mL and one of 512 μg/mL against S. aureus 10 were observed. The EOBD synergistically modulated the Norfloxacin antibiotic against P. aeruginosa 24, with a MIC reduction from 50.8 to 6.35 μg/mL, a Gentamicin MIC reduction from 20.16 to 4 μg/mL, and an Ampicillin MIC reduction from 645.1 to 512 μg/mL. The essential oil synergistically modified Norfloxacin activity against E. coli 06 with a MIC reduction from 40.32 to 3.17 μg/mL, and a Gentamicin MIC reduction from 50.8 to 25.4 μg/mL. The essential oil also showed synergism against S. aureus 10 when associated with Norfloxacin, with a MIC reduction from 322.54 to 203.2 μg/mL, whilst when associated with Ampicillin, it demonstrated synergism by reducing the MIC from 80.6 to 20.16 μg/ml. Results from this research revealed that the EOBD is a promising natural product with antimicrobial potential, both directly and in combination with antibiotics, for clinical use against Gram-positive and Gram-negative bacteria.

Effect of interaction with food constituents on plant extracts antibacterial activity

Gaillac red wine powder and Cinnamon cassia essential oil were selected for their in vitro antibacterial activity against Staphylococcus aureus CNRZ3 and Listeria innocua LRGIA 01, respectively. In order to assess the potential application of Gaillac wine powder to the preservation of raw meat, its antibacterial activity was assayed in Mueller Hinton broth supplemented with up to 20% (w/w) bovine meat proteins (bovine meat protein content): Gaillac wine powder as well as resveratrol, a stilbene polyphenol present in red wine, lost their antibacterial activity, likely as a result of interactions of Gaillac wine antibacterial molecules with bovine meat proteins at the expense of their interactions with S. aureus CNRZ3 cells. Cinnamon cassia essential oil antibacterial activity assays in Tryptone Soya broth, skimmed, semi-skimmed, and whole milk showed that its antibacterial activity was significantly reduced by milk fat globules but not by milk proteins: it could thus be used for the preservation of skimmed milk. The developed methodology based on the use of microbiological media mimicking the composition of perishable foods or of liquid foods such as sterilized milk with various milk fat contents could be used for the rapid screening of antibacterial plant extracts of interest for perishable foods preservation.

Chemical composition and antibacterial activity of oils from Chrysicthys nigrodigitatus and Hepsetus odoe, two freshwater fishes from Yabassi, Cameroon

BackgroundsOils of fish origin are a very rich source of Omega − 3 and Omega − 6 fatty acids. They have been suggested to provide numerous health benefits for humans involving antimicrobial properties. Chrysichthys nigrodigitatus and Hepsetus odoe are two fishes well known in Cameroon. The chemical composition and the antibacterial activity of these fishes derived oils are unknown. The study was designed to valorise C. nigrodigitatus and H.s odoe oils activity against food poisoning bacteria.MethodsOils were extracted by pressing and maceration methods. Their quality was assessed by analysing quality indexes including peroxides, acid, iodine, anisidine and thiobarbituric acid values. Chemical analysis was established by gas chromatography coupled to flame ionization detector. Antibacterial activity was evaluated by broth microdilution method.ResultsC. nigrodigitatus oil obtained by maceration exhibited highest acid (7.33 ± 0.00 mg KOH/g), anisidine (34.5 ± 1.84) and thiobarbituric acid (7.50 ± 0.30 μmol MDA/Kg) values compared to that obtained by pressing method (9.13 ± 0.64 and 6.72 ± 0.34 μmol MDA/Kg) respectively. H. odoe oil obtained by pressing method showed highest peroxide value (6.22 ± 1.31 meq O2/kg). Oil chemical analysis revealed long chain polyunsaturated fatty acids of the ω-3 family: linolenic acid (C18:3); eicosapentaenoic acid (C20:5) and docosahexaenoic acid (C22:6) and ω-6 family; arachidonic acid (C20:4). In addition, C. nigrodigitatus oil obtained by pressing and maceration methods showed Minimum Inhibitory Concentrations (MIC) values ranging from 32 to 64 mg/ml. H. odoe oil obtained by pressing method revealed MIC values ranging between 8 and 64 mg/ml.ConclusionsC. nigrodigitatus and H. odoe oils have activity against food poisoning bacteria, due to their chemical composition.

Effect of Extraction Process on Composition, Antioxidant and Antibacterial Activity of Oil from Yellow Passion Fruit (Passiflora edulis Var. Flavicarpa) Seeds

In this study, the effect of different extraction methods including subcritical fluid extraction (SubFE) with compressed propane at 30 and 60 °C and pressures from 2 to 8 MPa, a solvent extraction using Soxhlet (SE) apparatus with two different solvents (n-hexane and ethanol) and the ultrassound-assisted extraction (UAE) with ethanol as solvent on the extraction yield, physicochemical properties, fatty acids profile and tocopherol content, antioxidant and antibacterial activities of organic yellow passion fruit (Passiflora edulis var. flavicarpa). Higher yields were obtained by SE with n-hexane (26.12%) and compressed propane at 30 °C and 8 MPa (24.68%). The physicochemical parameters were consistent with the requirements of Codex Alimentarius regarding the most popular plant oils. Higher content of unsaturated fatty acids (86.65%) and linoleic acid (68.99%) was obtained by compressed propane at 30 °C and 2 MPa. The oils obtained by Soxhlet with n-hexane and compressed propane at 60 °C and 2 MPa showed higher tocopherol content (8.22 and 5.98 mg/100 goil, respectively). All oil samples presented high antioxidant performance and showed antibacterial activity against Escherichia coli, Salmonella enteritidis, Staphylococcus aureus and Bacillus cereus. This study further confirms that organic yellow passion fruit seed oils represent a good source of essential unsaturated fatty acids and demonstrated that there is an opportunity to add value for this agroindustrial waste with the use of unconventional extraction methods such as compressed propane, a green recovery technology yet still unexplored for seed oil extraction.

Artemisia herba-alba Asso. essential oil antibacterial activity and acute toxicity

Artemisia herba-alba Asso., known as the desert wormwood, is a medicinal plant and its essential oil is used in Algerian herbal medicine. In the present study the in vitro antibacterial activity against 21 bacterial strains and chemical composition of Artemisia herba-alba essential oil were investigated. The acute toxicity by determination of the median lethal dose was also studied. The results of gas chromatography/mass spectrometry analysis of the essential oil gave 19 compounds accounting for 98.7% and the major constituent was camphor with an amount of 50.7%. A significant antibacterial effect was observed with important zones of inhibition against Klebsiella oxytoca (31.3 mm) by disc diffusion method and against Acinetobacter baumannnii (47.6 mm) by microatmoshphere method. The minimum inhibitory concentration and the minimum bactericidal concentration values were ranging from 5 to 10 mg mL−1 and 10–20 mg mL−1, respectively. Moreover, their ratio exhibited by the essential oil was 2. The bactericidal end point was achieved after 24 h of exposure to the essential oil, for all the bacteria assayed. The oil was slightly toxic with a median lethal dose of 615 mg kg−1. The results of this study suggest that the essential oil of Artemisia herba-alba can be a source of natural antibacterial agents with potential pharmacological applications.

Constituents of Volatile Oil from Bark of Clerodendrum serratum (L.) and its Antibacterial Activity

Volatile oil composition of the bark of Clerodendrum serratum (L.) was reported. Oil was extracted by hydrodistillation and analyzed through GC-MS. 48 Constituents were successfully identified that accounted for 93.35 % of the total composition. The most abundant constituents found in the bark were linoleic acid (20.1 %), α-zingiberene (10.3 %) o-cymene (9.3 %), palmitic acid, (9.0 %), oleic acid (7.0 %), and β-sesquiphellandrene (5.3 %). Moreover, antibacterial activity of oil was evaluated against four different pathogenic strains namely Methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli (E. coli), Methicillin-sensitive Staphylococcus aureus (MSSA) and Proteus spp. The results of antibacterial activity demonstrated that the activity of oil follows the principle of dose-dependency. The zone of inhibition at the maximum dose of 200 μL were 38 mm for Proteus spp., 34 mm for E. coli, 31 mm for MRSA and 30 mm for MSSA.

Composition and Antibacterial Activity of the Essential Oils of Orthosiphon stamineus Benth and Ficus deltoidea Jack against Pathogenic Oral Bacteria.

In this study, the essential oils of Orthosiphon stamineus Benth and Ficus deltoidea Jack were evaluated for their antibacterial activity against invasive oral pathogens, namely Enterococcus faecalis, Streptococcus mutans, Streptococcus mitis, Streptococcus salivarius, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Fusobacterium nucleatum. Chemical composition of the oils was analyzed using gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The antibacterial activity of the oils and their major constituents were investigated using the broth microdilution method (minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC)). Susceptibility test, anti-adhesion, anti-biofilm, checkerboard and time-kill assays were also carried out. Physiological changes of the bacterial cells after exposure to the oils were observed under the field emission scanning electron microscope (FESEM). O. stamineus and F. deltoidea oils mainly consisted of sesquiterpenoids (44.6% and 60.9%, respectively), and β-caryophyllene was the most abundant compound in both oils (26.3% and 36.3%, respectively). Other compounds present in O. stamineus were α-humulene (5.1%) and eugenol (8.1%), while α-humulene (5.5%) and germacrene D (7.7%) were dominant in F. deltoidea. The oils of both plants showed moderate to strong inhibition against all tested bacteria with MIC and MBC values ranging 0.63–2.5 mg/mL. However, none showed any inhibition on monospecies biofilms. The time-kill assay showed that combination of both oils with amoxicillin at concentrations of 1× and 2× MIC values demonstrated additive antibacterial effect. The FESEM study showed that both oils produced significant alterations on the cells of Gram-negative bacteria as they became pleomorphic and lysed. In conclusion, the study indicated that the oils of O. stamineus and F. deltoidea possessed moderate to strong antibacterial properties against the seven strains pathogenic oral bacteria and may have caused disturbances of membrane structure or cell wall of the bacteria.