Antimicrobial and antioxidant activity of spice essential oils

Essential oils of anise, bastard cardamom, cinnamon, dill, mace, zedoary, prikhom, and bitter ginger were determined for their antimicrobial and antioxidant activities. Of all, cinnamon oil had the highest antibacterial activity. The most sensitive bacteria was Bacillus cereus (0.5mg/mL minimum inhibitory concentration, MIC). Anise, cinnamon, dill, and prikhom exhibited strong antifungal activity against Rhodotorula glutinis, Aspergillus ochraceus, and Fusarium moniliforme. Two oil combinations: i) cinnamon and mace oils and ii) cinnamon and prikhom oils showed a synergistic effect against Staphylococcus aureus, Pseudomonas fluorescens, and Salmonella Rissen (0.32–0.38 mg/mL fractional inhibitory concentration index, FICI). Cinnamon, mace, and prikhom oils had strong antioxidant activity with 0.29–5.66 mg/mL IC₅₀, 61.46–68.52% antioxidant activity, 0.22–2.19 mM/mg reducing capacity, and 78.28–84.30% inhibition by 2,2-diphenyl-1-picrylhydrazyl (DPPH), β-carotene bleaching, ferric reducing (FRAP), and superoxide anion scavenging activity assays, respectively. These oils contained high amount of total phenolics (51.54–140.9 μg gallic acid equivalents/mg oil).     

Antimycotoxigenic characteristics of Rosmarinus officinalis and Trachyspermum copticum L. essential oils

Aflatoxin B1 (AFB1) is a highly toxic and carcinogenic metabolite produced by Aspergillus species on food and agricultural commodities. Natural products may regulate the cellular effects of aflatoxins and evidence suggests that aromatic organic compounds of spices can control the production of aflatoxins. With a view to controlling aflatoxin production, the essential oils from Rosmarinus officinalis and Trachyspermum copticum L. were obtained by hydrodistillation. Antifungal activities of the oils were studied with special reference to the inhibition of Aspergillus parasiticus growth and aflatoxin production. Minimal inhibitory (MIC) and minimal fungicidal (MFC) concentrations of the oils were determined. T. copticum L. oil showed a stronger inhibitory effect than R. officinalis on the growth of A. parasiticus. Aflatoxin production was inhibited at 450 ppm of both oils with that of R. officinalis being stronger inhibitor. The oils were analyzed by GC and GC/MS. The major components of R. officinalis and T. copticum L. oils were Piperitone (23.65%), alpha-pinene (14.94%), Limonene (14.89%), 1,8-Cineole (7.43%) and Thymol (37.2%), P-Cymene (32.3%), gamma-Terpinene (27.3%) respectively. It is concluded that the essential oils could be safely used as preservative materials on some kinds of foods to protect them from toxigenic fungal infections.     

调味香料葛缕子精油的微波辅助提取及其抗氧化性研究

利用微波辅助水蒸气蒸馏法提取了葛缕子精油(CEO),其最佳条件是:破碎功率800W,破碎时间4min,料液比1∶50。最大出油率为4.2%。利用磷钼络合物法测定了精油的总抗氧化活性,邻苯三酚自氧化法测定其清除超氧阴离子自由基的能力,水杨酸法测定其羟基自由基清除能力,并与食用抗氧化剂没食子酸丙酯(PG)进行了比较。实验结果表明,在一定浓度范围内,葛缕子精油清除超氧阴离子自由基的能力强于PG;被测样品的羟基自由基清除率略低于PG。     

Antimicrobial and antioxidant activity of crude onion (Allium cepa,L.) extracts

Antioxidant and antimicrobial activity of the ethyl acetate and water subfractions of methanolic extracts of three Spanish onion varieties were assayed. Flavonoids were mainly present in ethyl acetate subfraction being 34.92 ± 0.75, 7.95 ± 0.16, 0.38 ± 0.01 μmol of rutin eq. g^?1 D.W. and its antioxidant capacity was 74.86 ± 1.77, 24.59 ± 0.67, 4.55 ± 0.44 μmol Trolox g^?1 D.W. of Grano de Oro, Fuentes de Ebro and Calçot de Valls varieties, respectively. The antimicrobial activity of flavonol standards and onion extracts was evaluated against some food spoiler microorganisms. Quercetin and kaempferol were inhibitory against gram positive bacteria such as Bacillus cereus, Staphylococcus aureus, Microcroccus luteus and Listeria monocytogenes. Gram negative bacteria Escherichia coli and Pseudomonas aeruginosa were less sensible to the antimicrobial effect of both flavonol standards and Candida albicans was totally resistant. Among the onion extracts tested only ethyl acetate subfraction showed antimicrobial inhibition.     

Antimicrobial activity of the essential oils of Thymus vulgaris L. measured using a bioimpedometric method.

The essential oils obtained from Thymus vulgaris L. harvested at four ontogenetic stages were evaluated for their biological activity and chemical composition. The thyme essential oils were tested for their inhibitory effects against nine strains of gram-negative bacteria and six strains of gram-positive bacteria. The bioimpedance method was chosen for studying the antibacterial activity of the essential oils and the parameter chosen for defining and quantifying the antibacterial activity of the essential oils was the detection time. The plate counting technique was used to study the inhibitory effect by direct contact. All the thyme essential oils examined had a significant bacteriostatic activity against the microorganisms tested. This activity was more marked against the gram-positive bacteria. The oil from thyme in full flower was the most effective at stopping the growth of the microbial species examined. The oils tested were also shown to have good antibacterial activity by direct contact, which appeared to be more marked against the gram-negative bacteria. Only a few of the species were capable of recovering at least 50% of their metabolic function after contact with the inhibitor, while most of the strains were shown to have been inactivated almost completely. Escherichia coli O157:H7 was the most sensitive species, given that after contact with even the lowest concentration of oil cells could not be recovered.     

Reevaluation of antimicrobial and antioxidant activity of Thymus spp. extracts before and after encapsulation in liposomes

The antioxidant and antimicrobial activity of four Thymus species (boissieri, longicaulis, leucospermus, and ocheus) extracts were determined. Two methods (Rancimat and malondialdehyde by high-performance liquid chromatography) were used to measure the antioxidant action in comparison with common commercial antioxidants, including butylated hydroxytoluene and alpha-tocopherol. The extracts that presented high antioxidant activity were encapsulated in liposomes and their antioxidant action was again estimated. Thermal-oxidative decomposition of the samples (pure liposomes and encapsulating extracts) was studied using the differential scanning calorimetry method. The modification of the main transition temperature for the lipid mixture and the splitting of the calorimetric peak in the presence of the antioxidants were also demonstrated by differential scanning calorimetry. All extracts showed antioxidant and antimicrobial activities. Some extracts showed superior or equal antioxidant activity to alpha-tocopherol. When the extracts were encapsulated in liposomes, their antioxidant as well as antimicrobial activities proved to be superior from the same extracts in pure form.     

Antimicrobial activity of the essential oils of Turkish plant spices

The antimicrobial activity of the essential oils of nine plant spices (savory, laurel, oregano, basil, cumin, seafennel, myrtle, pickling herb, and mint) were tested at three concentrations (1, 10, and 15%) and tested on various microorganisms (Salmonella typhimurium, Bacillus cereus, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Yersinia enterocolitica, Saccharomyces cerevisiae, Candida rugosa, Rhizopus oryzae and Aspergillus niger). The results showed that the essential oils tested varied in their antimicrobial activity. Individual or combinations of plant essential oils may provide an efficacious mixture for the inactivation of pathogenic and spoilage microorganisms, and to achieve adequate shelf-life of foods.     

Antimicrobia activity of garlic (Allium sativum L.) and holy basil (Ocimum sanctum L.) essential oils applied by liquid vs. vapour phases

Antimicrobial activity of garlic (Allium sativum L.) and holy basil (Ocimum sanctum L.) essential oils (GEO and HBEO, respectively) was evaluated in liquid vs. vapour phases. Diallyl disulphide and diallyl trisulphide in GEO while eugenol, caryophyllene and methyl eugenol in HBEO were predominant active compounds. Individually, GEO was highly effective in the vapour phase, showing the greatest antimicrobial activity (P ≤ 0.05) against Bacillus cereus and Staphylococcus aureus with complete inhibition, followed by Salmonella typhimurium and Pseudomonas fluorescens, but had no effect on Escherichia coli, Lactobacillus plantarum or Listeria monocytogenes. The combined GEO:HBEO (a 1:1 ratio) at 30 μL demonstrated inhibitive activity against all bacteria tested with complete inhibition against B. cereus and S. aureus. Minimum bactericidal concentration (MBC) of the combined oil was <0.4% v/v, except for P. fluorescens requiring a higher MBC (1.5%, v/v). This study demonstrated potential of the combined GEO:HBEO to be used for food preservation applications.     

Antimicrobial and antioxidant properties of the essential oils and methanol extract from Mentha longifolia L. ssp. longifolia

This study was designed to evaluate antimicrobial and antioxidant activities of the essential oil and methanol extract from Mentha longifolia ssp. longifolia. The essential oil showed strong antimicrobial activity against all 30 microorganisms tested whereas the methanol extract almost remained inactive. In contrast, the extract showed much better activity than the essential oil in antioxidant activity assays employed, e.g. in the inhibition of free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene/linoleic acid systems. In the former, the extract was able to reduce the stable free radical DPPH with an IC₅₀ of 57.4 μg/ml while that of the oils was 10 700 μg/ml. When compared to BHT, a synthetic antioxidant, both showed weaker antioxidative potential. Similarly, in β-carotene/linoleic acid assay, these samples were not effectively able to inhibit the linoleic acid oxidation; exhibiting only 24% and 36% inhibitions at 2 mg/ml, respectively; both were far below than that of BHT. Total phenolic constituent of the extract was 4.5 g/100 g as gallic acid equivalent. GC–MS analysis of the oil resulted in the identification of 45 constituents, cis-piperitone epoxide, pulegone and piperitenone oxide being the main components.     

Fatty acid and essential oil composition of three Tunisian caraway (Carum carvi L.) seed ecotypes

BACKGROUND: The essential oil and fatty acid composition of Tunisian annual caraway (Carum carvi L.) seeds from three ecotypes was investigated by gas chromatography and gas chromatography–mass spectrometry analyses. RESULTS: Total fatty acid (TFA) proportion of caraway seeds varied from 2.95% to 5.68% (w/w). The fatty acid composition revealed that Tunisian caraway seed oil is rich in an unusual fatty acid—petroselinic acid—the proportion of which varied from 31.53% and 38.36% of TFA. Essential oil yields were relatively low and ranged from 0.86% to 1.20% (w/w). Forty‐one volatile compounds were identified, the main ones being carvone (76.78–80.53%) and limonene (13.05–20.29%). CONCLUSION: Tunisian caraway seed oil is rich in an unusual fatty acid—petroselinic acid—which is of potential industrial significance. In addition, Tunisian caraway essential oil is carvone chemotype. This fact is of great economic interest due to the several applications of carvone in the alimentary and medicinal industries. Copyright © 2009 Society of Chemical Industry     

Essential oils of Origanum vulgare L. subsp. glandulosum (Desf.) Ietswaart from Tunisia: chemical composition and antioxidant activity

BACKGROUND: Characterisation of the essential oils from O. glandulosum collected in three locations of Tunisia, chemical composition and the evaluation of their antioxidant activities were carried out. RESULTS: The essential oils from Origanum vulgare L. subsp. glandulosum (Desf.) Ietswaart collected from three localities of north Tunisia—Krib, Bargou and Nefza—were obtained in yields of 2.5, 3.0 and 4.6% (v/w), respectively. The essential oils were analysed by GC and GC/MS and assayed for their total phenolics content, by the Folin–Ciocalteu method, and antioxidant effectiveness, using the 2,2‐diphenyl‐1‐picrylhydrazil (DPPH) radical scavenging assay. The main components of these essential oils, from Nefza, Bargou and Krib, were p‐cymene (36%, 40% and 46%), thymol (32%, 39% and 18%), γ‐terpinene (24%, 12% and 16%) and carvacrol (2%, 2% and 15%), respectively). The ability to scavenge the DPPH radicals, expressed by IC₅₀, ranged from 59 to 80 mg L^?1. The total phenolic content, expressed in gallic acid equivalent (GAE) g kg^?1 dry weight, varied from 9.37 to 17.70 g kg^?1 dw. CONCLUSIONS: A correlation was identified between the total phenolic content of the essential oils and DPPH radical scavenger capacity. The occurrence of a p‐cymene chemotype of O. glandulosum in the northern region of Tunisia is demonstrated. Copyright © 2010 Society of Chemical Industry     

Antimicrobial activity of essential oils from plants against selected pathogenic and saprophytic microorganisms.

The beneficial health effects of extracts from many types of plants that are used as seasoning agents in foods and beverages have been claimed for centuries. The purpose of this study was to examine the effectiveness of selected herb and spice essential oils for control of growth and survival of microorganisms. Inhibition of growth was tested by the paper disc agar diffusion method. Antibiotic susceptibility discs were used as control. Minimum lethal concentration (MLC) was determined by the tube dilution method. Essential oils from anise, angelica, basil, carrot, celery, cardamom, coriander, dill weed, fennel, oregano, parsley, and rosemary were evaluated. Inhibition ranged from complete with oregano to no inhibition with carrot oil for each of the test strains that included: Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O:157:H7, Yersinia enterocolitica, Pseudomonas aeruginosa, Lactobacillus plantarum, Aspergillus niger, Geotrichum, and Rhodotorula. Oregano essential oil showed the greatest inhibition (zone, > or = 70 to 80 mm) (MLC, approximately 8 ppm). Coriander and basil were also highly inhibitory (MLC, approximately 25 to 50 ppm) to E. coli O:157:H7 and to the other bacteria and fungi tested. Anise oil was not particularly inhibitory to bacteria (inhibition zone, approximately 25 mm); however, anise oil was highly inhibitory to molds. Because some of the herbal and spice essential oils are highly inhibitory to selected pathogenic and spoilage microorganisms, they may provide alternatives and supplements to conventional antimicrobial additives in foods.     

Chemistry and antioxidant activity of essential oil and oleoresins of black caraway (Carum bulbocastanum) fruits: Part 69

BACKGROUND: The present study describes the chemical analysis of the essential oil and oleoresins from caraway, which have been studied by using GC–MS. The paper also explains the importance of the extracted oil and oleoresins in the antioxidant activities of target plant species. RESULTS: GC–MS analysis of caraway essential oil showed 51 compounds representing about 96.6% of the total weight. The major components were dillapiole (44.6%), germacrene‐β (14.1%), nothoapiole (8.3%), and β‐selinene (6.8%), along with many other components in minor amounts. Major components in ethyl acetate and iso‐octane oleoresins are dillapiole, nothoapiole and germacrene‐β, whereas in ethanol oleoresin contains dillapiole (25%), sitosterol (21.3%) stigmasterol (9.5%) and nothoapiole (8.1%). The antioxidant activity was evaluated by various antioxidant assays such as peroxide, thiobarbituric acid and p‐anisidine values. These experiments were further supported by other complementary antioxidant assays such as ferric thiocyanate method in linoleic acid system, reducing power, and scavenging effects on 1,1′‐diphenyl‐2‐picrylhydrazyl (DPPH). Both the caraway volatile oil and its oleoresins showed strong antioxidant activity in comparison with butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). CONCLUSION: This study provides additional information about the chemistry and antioxidant activity of caraway. Hence, caraway may be used as natural food preservatives. Copyright © 2009 Society of Chemical Industry     

植物精油的提取、成分分析以及抗氧化活性研究

植物精油近年来得到越来越多的关注,人们对于精油的功效寄予厚望,对多种植物精油进行了研究,包括唇形科、菊科、桃金娘科以及姜科等植物的精油。不同植物精油在成分和含量上存在较大差异,因此在生物活性方面也存在一定差异。文章主要对近几年来关于植物精油的提取、成分分析以及抗氧化活性的研究进行总结与概述,为精油的开发利用奠定研究基础。      

狮头柑挥发油化学成分分析

采用水蒸气蒸馏提取挥发油,用Gas Chromatography/Mass Spectrometry(GC-MS)对狮头柑挥发油化学成分进行了定性定量分析。狮头柑的出油率很高,达到3.78%。检出42种成分,其主要成分为柠檬精油(75.5%)。     

Antimicrobial activity in the vapour phase of a combination of cinnamon and clove essential oils

The antimicrobial activity of the vapour generated by a combination of cinnamon and clove essential oils against the growth of four Gram-negative (Escherichia coli, Yersinia enterocolitica, Pseudomonas aeruoginosa and Salmonella choleraesuis) and four Gram-positive bacteria (Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus and Enterococcus faecalis) was assessed by means of the fractional inhibitory concentration index (FIC) of the mixture. The presence of synergism or antagonism effects depended on the reference parameter used to estimate such an index. If the minimal inhibitory concentrations were applied, the vapours of the combination of essential oils exerted an antagonistic effect on the growth of E. coli, while they wielded a synergistic effect for the inhibition of L. monocytogenes, B. cereus and Y. enterocolitica when the concentrations of maximal inhibition were used. This fact revealed a clear concentration-dependent interaction.     

Antimicrobial activity of essential oils on the native microflora of organic Swiss chard

The antimicrobial activity of several essential oils on the native microflora of Swiss chard was evaluated. The agar diffusion technique (paper disc) was used to establish, in a rapid way, the susceptibility of the native microflora to the different essential oils and to choose those with the greatest antimicrobial activity. An optical method (turbidimetry) and a microdilution method (plate count) were used to determine the minimum bactericidal concentration (MBC) and the minimum inhibitory concentration (MIC). Both methods produced similar results. The essential oils of Eucalyptus globules, Melaleuca alternifolia, Pimpinella anisum and Syzygium aromaticum presented the largest antimicrobial activity. For these oils, the MBC values were in the range of 0.093–1.5 mL/100 mL.