Inhibition of the Citrus Bacterial Pathogen Xanthomonas axonopodis pv. citri through Aloysia gratissima Essential Oil and Flourensia spp. Extracts and Prenylflavonoids

2021 ◽  
Vol 18 ◽  
Author(s):  
Miguel Ángel Castillo ◽  
María Guadalupe Reyes ◽  
Elsa Mónica Farfán Torres ◽  
María Laura Uriburu

Background: Xanthomonas axonopodis pv. citri is a gram-negative bacterium that affects citrus crops, causing a disease known as citrus canker. Although essential oils and other compounds isolated from plants represent a natural alternative to treat this disease, they have the disadvantage of having low solubility in the media in which the bioassays to determine antimicrobial activity are performed. This has led several researchers to evaluate the solubility of plant essential oils in alternative solvents. Objectives: The aim of this study was to evaluate the solubility of the essential oil from Aloysia gratissima as well as that of low-polarity extracts and pure compounds of the genus Flourensia in diluted agar/Tween 80 solutions to test and improve their antimicrobial activity against Xanthomonas axonopodis pv. citri. Methods: Antimicrobial activity against Xanthomonas axonopodis pv. citri was determined by bioautography, agar diffusion, and microdilution methods. Results: The A. gratissima oil showed increased activity in the agar (0.15 % m/v)/Tween80 (0.5 % v/v) 1:1 mixture, with MIC values ranging from 75 to 100 µL/mL, while Flourensia spp. extracts were more soluble in agar solution (0.15 % m/v). The pure compounds tested presented MIC values ranging from 50 to 150 µg/mL. Conclusion: The proven antimicrobial activity of both Aloysia gratissima essential oil and Flourensia spp. extracts and pure compounds allows proposing these natural products as potential antimicrobial agents in the control of citrus canker.

Molecules ◽  
2020 ◽  
Vol 25 (6) ◽  
pp. 1303 ◽  
Author(s):  
Do N. Dai ◽  
Nguyen T. Chung ◽  
Le T. Huong ◽  
Nguyen H. Hung ◽  
Dao T.M. Chau ◽  
...  

Members of the genus Cinnamomum (Lauraceae) have aromatic volatiles in their leaves and bark and some species are commercially important herbs and spices. In this work, the essential oils from five species of Cinnamomum (C. damhaensis, C. longipetiolatum, C. ovatum, C. polyadelphum and C. tonkinense) growing wild in north central Vietnam were obtained by hydrodistillation, analyzed by gas chromatography and screened for antimicrobial and mosquito larvicidal activity. The leaf essential oil of C. tonkinense, rich in β-phellandrene (23.1%) and linalool (32.2%), showed excellent antimicrobial activity (MIC of 32 μg/mL against Enterococcus faecalis and Candida albicans) and larvicidal activity (24 h LC50 of 17.4 μg/mL on Aedes aegypti and 14.1 μg/mL against Culex quinquefasciatus). Cinnamomum polyadelphum leaf essential oil also showed notable antimicrobial activity against Gram-positive bacteria and mosquito larvicidal activity, attributable to relatively high concentrations of neral (11.7%) and geranial (16.6%). Thus, members of the genus Cinnamomum from Vietnam have shown promise as antimicrobial agents and as potential vector control agents for mosquitoes.


2009 ◽  
Vol 3 (1) ◽  
pp. 103-107 ◽  
Author(s):  
Hend A. Hamedo

Technological application of essential oils, as natural antimicrobial agents, to reduce the effect of pathogenic microorganisms, requires new methods of detection. The present work evaluated the parameters of antimicrobial activity of the essential oils of rosemary (Rosmarinus officinalis) on two pathogenic strains Escherichia coli and Staphylococcus aureus. The MBC and MIC values were of 2.5, 25 μl ml-1, and values of 1.25 and 5 μl ml-1 for the two strains respectively. In this study, an attempt has been made to evaluate randomly amplified polymorphic DNA (RAPD) analysis for its potential to establish antimicrobial effect of rosemary essential oil. For the preliminary assessment, this study compared the effects occurring at molecular levels in E. coli and Staph. aureus exposed to rosemary essential oil at the MIC concentrations for the two organisms. The qualitative modifications arising in random amplified polymorphic DNA (RAPD) profiles as a measure of DNA effects were compared with control which showed many differences. In conclusion, the measurement of parameters at molecular levels is valuable for investigating the specific effects of agents interacting with DNA.


Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1574
Author(s):  
Zoran S. Ilić ◽  
Lidija Milenković ◽  
Ljubomir Šunić ◽  
Nadica Tmušić ◽  
Jasna Mastilović ◽  
...  

The aim of this study was to determine the antimicrobial activity of essential oils obtained from sweet basil (Ocimum basilicum L. cv. ‘Genovese’) cultivated in the open field under different shading conditions (red, blue, and pearl nets with a shade index of 50% and full sunlight exposure (control plants)), harvested at different times. The antimicrobial activity of basil essential oils (BEOs) obtained from all samples was determined for four microorganisms, while determinations for an additional five microorganisms included samples from non-shaded plants, plants grown under red and pearl nets, and second harvest of plants grown under blue net. Basil essential oil exhibited antimicrobial activity surpassing the activity of relevant commercial antibiotics regardless of growing conditions in the case of B. cereus, K. pneumoniae and C. albicans, while superior antimicrobial activity was exhibited in the case of essential oils from plants grown under blue nets in the case of S. aureus, E. coli and P. vulgaris. The influence of the application of colored shading nets was highly significant (p < 0.01) in the cases of all analyzed microorganisms except C. albicans and P. aeruginosa, while the influence of harvest time was proven in the cases of all microorganisms except K. pneumoniae. ANOVA proved that antimicrobial activities are highly dependent on the methods of plant production, shading treatment, and harvest time. Obtained results are discussed in relation to previously determined composition and yield of essential oils from basil grown under shade nets and harvested in different periods.


Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2403 ◽  
Author(s):  
R. Syafiq ◽  
S. M. Sapuan ◽  
M. Y. M. Zuhri ◽  
R. A. Ilyas ◽  
A. Nazrin ◽  
...  

Recently, many scientists and polymer engineers have been working on eco-friendly materials for starch-based food packaging purposes, which are based on biopolymers, due to the health and environmental issues caused by the non-biodegradable food packaging. However, to maintain food freshness and quality, it is necessary to choose the correct materials and packaging technologies. On the other hand, the starch-based film’s biggest flaws are high permeability to water vapor transfer and the ease of spoilage by bacteria and fungi. One of the several possibilities that are being extensively studied is the incorporation of essential oils (EOs) into the packaging material. The EOs used in food packaging films actively prevent inhibition of bacteria and fungi and have a positive effect on food storage. This work intended to present their mechanical and barrier properties, as well as the antimicrobial activity of anti-microbacterial agent reinforced starch composites for extending product shelf life. A better inhibition of zone of antimicrobial activity was observed with higher content of essential oil. Besides that, the mechanical properties of starch-based polymer was slightly decreased for tensile strength as the increasing of essential oil while elongation at break was increased. The increasing of essential oil would cause the reduction of the cohesion forces of polymer chain, creating heterogeneous matrix and subsequently lowering the tensile strength and increasing the elongation (E%) of the films. The present review demonstrated that the use of essential oil represents an interesting alternative for the production of active packaging and for the development of eco-friendly technologies.


Author(s):  
D. B. Thin ◽  
V. Q. Thanh ◽  
B. B. Thinh

Abstract. Recent years have seen the development of bacterial resistance to currently available antibiotics, which necessitates a search for new antimicrobial agents. Amomum muricarpum Elmer is a widely used medicinal plant species in the genus Amomum (family Zingiberaceae) that is commonly found in Laos, the Philippines, China, and Vietnam. The present article describes the chemical composition and antimicrobial activity of essential oils extracted from the leaves and rhizomes of A. muricarpum from North Vietnam. The hydrodistilled essential oil was analyzed using gas chromatography and gas chromatography-mass spectrometry, with the broth microdilution method designed to evaluate its antimicrobial efficacy. The absolute yield of essential oils amounted to 0.11% and 0.13% (v/w) for leaves and rhizomes, respectively, on a dry weight basis. It was found that the leaves and rhizomes of A. muricarpum produce oils abounding in monoterpenes. Of the total identified volatile components in the leaf oil (97.18%), three main constituents include α-pinene (40.45%), linalool (12.34%), and β-pinene (10.31%). In the rhizome oil, the main constituents include α-pinene (48.10%), β-pinene (20.32%), and linalool (7.56%) of the total identified volatile components (98.08%). An antimicrobial activity test indicates that essential oils from the leaves and rhizome of A. muricarpum inhibit the growth of Staphylococcus aureus ATCC 25923, with a minimum inhibitory concentration (MIC) of 200 µg/ml. In addition, the rhizome essential oil also exhibits antimicrobial activity against Bacillus cereus ATCC 14579, with a MIC value of 200 µg/ml. The results indicate the potential of essential oils extracted from A. muricarpum as a source of antimicrobial agents.


Plants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 544 ◽  
Author(s):  
Nguyen Thi Giang An ◽  
Le Thi Huong ◽  
Prabodh Satyal ◽  
Thieu Anh Tai ◽  
Do Ngoc Dai ◽  
...  

Mosquitoes are important vectors of several diseases, and control of these insects is imperative for human health. Insecticides have proven useful in controlling mosquito populations, but insecticide resistance and environmental concerns are increasing. Additionally, emerging and re-emerging microbial infections are problematic. Essential oils have been shown to be promising mosquito larvicidal agents as well as antimicrobial agents. In this work, the essential oils from four species of Myrtaceae (Baeckea frutescens, Callistemon citrinus, Melaleuca leucadendra, and Syzygium nervosum) growing wild in central Vietnam have been obtained by hydrodistillation and analyzed by gas chromatographic techniques. The essential oils have been screened for mosquito larvicidal activity against Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus, and for antimicrobial activity against Enterococcus faecalis, Staphylococcus aureus, and Candida albicans. Callistemon citrinus fruit essential oil, rich in α-pinene (35.1%), 1,8-cineole (32.4%), limonene (8.2%), and α-terpineol (5.8%) showed good larvicidal activity with 24-h LC50 = 17.3 μg/mL against both Ae. aegypti and Cx. quinquefasciatus, and good antibacterial activity against E. faecalis (minimum inhibitory concentration (MIC) = 16 μg/mL) The 48-h larvicidal activities of M. leucadendra leaf essential oil, rich in α-eudesmol (17.6%), guaiol (10.9%), linalool (5.1%), (E)-caryophyllene (7.0%), and bulnesol (3.6%) were particularly notable, with LC50 of 1.4 and 1.8 μg/mL on Ae. aegypti and Cx. quinquefasciatus. Similarly, M. leucadendra bark essential oil, with α-eudesmol (24.1%) and guaiol (11.3%), showed good antibacterial activity against. E. faecalis. Both B. frutescens and C. citrinus leaf essential oils demonstrated anti-Candida activities with MIC values of 16 μg/mL. The results of this investigation suggest that essential oils derived from the Myrtaceae may serve as “green” alternatives for the control of mosquitoes and/or complementary antimicrobial agents.


2012 ◽  
Vol 262 ◽  
pp. 422-425
Author(s):  
Guang Fa Liu ◽  
Jian Qing Wang ◽  
Ya Zhu Zhao

This work explored the use of microcapsules of natural plant essential oils to increase the shelf life of strawberries during storage. First, antimicrobial tests were performed with selected essential oils to evaluate their antimicrobial capacities against moulds isolated from strawberries. Oregano essential oil was found as strong bioactive agents against moulds from strawberries, whereas cinnamon essential oil had lower antimicrobial properties. Then, microcapsules of oregano essential oil were prepared with oregano essential oil, sodium alginate, Tween 80, and monoglycerides, and their internal structure were observed by SEM, and their oils contain were tested by UV-visible spectrophotometer inspection. Different amounts of microcapsules of oregano essential oil were wrapped into small polypropylene non-woven package, and they were pasted on the internal of corrugated boxes. Finally, freshly picked strawberries were put into corrugated boxes and stored at room temperature (from 16°C to 18°C) for 4 days. The results showed that the use of microcapsules of oregano essential oil could effectively inhibit the decay of strawberries, maintain their quality, and extend their shelf life. Strawberries presented the best quality when the amount of microcapsules arrived at 0.828 grams per 500 grams of strawberries.


2020 ◽  
Vol 16 ◽  
Author(s):  
Mojgan Alizadeh ◽  
Akram Arianfar ◽  
Ameneh Mohammadi

Objective: Ziziphora clinopodioides is an edible medicinal plant belongs to the Labiatae family that widespread all over Iran. It used as culinary and also in cold and cough treatments in Iran. The aim of present work was to evaluate the effect of different timeframes during the hydrodistillation on essential oil composition, antimicrobial and antioxidant activity. Materials and Methods: The essential oil of Z. clinopodiodes was extracted via hydrodistillation with Clevenger apparatus. The fractions of essential oil were captured at 6 times from the beginning of the distillation: (10, 20, 60, 120, 180 and 240 min). The fractions of essential oil were analyzed by GC/MS and their antibacterial, antifungal and antioxidant activities were studied by Disk - well diffusion and DPPH methods respectively. Results: Six distillation times and whole essential oil were captured during the hydrodistillation. Essential oil yield dropped off significantly during distillation progressed (1.0% for 10 min and 0.025 for 240 min). 1,8 Cineol, Isomenthone, Pulegone, Piperitenone and Citronellic acid were major compounds in fractions and they were affected by distillation times. Pulegone was major compound in all of essential oils. In antioxidant activity assay, whole essential oil was stronger than was stronger than positive control and fractions of essential oil, because of higher levels of Isomenthone, Piperitenone and Citronellic acid. Strongest antimicrobial activity against S. aureus, E. coli and C. albicans was observed from 10 min fraction. Conclusion: Our results indicated that distillation time can create essential oils with specific properties and we can achieve to more efficient essential oil in short times.


Author(s):  
Mansureh Ghavam ◽  
Afsaneh Afzali ◽  
Maria Manconi ◽  
Gianluigi Bacchetta ◽  
Maria Letizia Manca

Abstract Background Essential oil of Rosa × damascena Herrm. is one of the most valuable and important raw materials for the flavor and fragrance industry. The cultivation of this plant has ancient origins, and Kashan was one of the first mountainous regions of Iran dealing with the cultivation of R. × damascena. In this study, both chemical composition and antimicrobial activity of different rose essential oils obtained from five mountainous areas of Kashan region (Maragh, Qamsar, Sadeh, Javinan, and Kamoo) has been investigated along with the influence of the environmental conditions on these properties. Results Results showed that yield and chemical composition of essential oils obtained from Rosa × damascena were significantly affected by the collection area. In particular, the yield of oils varied from ~0.08 to ~0.132% and citronellol (36.70-9.18%), geraniol (12.82-0.47%), nonadecane (22.73-10.36%), heneicosane (31.7-11.43%), and 1-nonadecene (6.03-3.93%) have been detected as main compounds in all the plants collected, but at different concentrations depending on the collection area. The best fragrance and the highest yield were found in the oil from Kamoo area. Similarly to the chemical composition, the antimicrobial activity of the essential oils was affected by their origin, and essential oil obtained from plants collected from Kamoo area disclosed the highest antibacterial and antifungal efficacy. Its inhibition halos were 17.33±0.58 mm against Aspergillus brasiliensis, 15.67±0.58 mm against Staphylococcus aureus, and 12.33±0. 58 mm against Streptococcus pyogenes. Essential oils of R. damascena were also effective against Gram-negative Pseudomonas aeruginosa and they had a MIC value of 62.50 μg/mL irrespective of the collection area (except the oil from Javinan area). On the contrary, the highest antifungal power against Candida albicans yeast was reached using the essential oil obtained from plants collected in Javinan region (MIC and MBC ~62.50 μg/mL). Conclusions Overall results underline the influence of environmental conditions of the different areas of Kashan region, on the chemical composition of and antimicrobial activity of the essential oils of Rosa × damascena. In addition, results disclosed that Kamoo seemed to be the most suitable area for the competitive cultivation of R. × damascena to the intensive production of aromatic flower oil and natural antimicrobial essential oils.


Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1406
Author(s):  
Rita Cava-Roda ◽  
Amaury Taboada-Rodríguez ◽  
Antonio López-Gómez ◽  
Ginés Benito Martínez-Hernández ◽  
Fulgencio Marín-Iniesta

Plant bioactive compounds have antimicrobial and antioxidant activities that allow them to be used as a substitute for synthetic chemical additives in both food and food packaging. To improve its sensory and bactericidal effects, its use in the form of effective combinations has emerged as an interesting possibility in the food industry. In this study, the antimicrobial activities of essential oils (EOs) of cinnamon bark, cinnamon leaves, and clove and the pure compounds vanillin, eugenol, and cinnamaldehyde were investigated individually and in combination against Listeria monocytogenes and Escherichia coli O157:H7. The possible interactions of combinations of pure compounds and EOs were performed by the two-dimensional checkerboard assay and isobologram methods. Vanillin exhibited the lowest antimicrobial activity (MIC of 3002 ppm against L. monocytogenes and 2795 ppm against E. coli O157:H7), while clove and cinnamon bark EOs exhibited the highest antimicrobial activity (402–404 against L. monocytogenes and 778–721 against E. coli O157:H7). For L. monocytogenes, pure compound eugenol, the main component of cinnamon leaves and clove, showed lower antimicrobial activity than EOs, which was attributed to the influence of the minor components of the EOs. The same was observed with cinnamaldehyde, the main component of cinnamon bark EO. The combinations of vanillin/clove EO and vanillin/cinnamon bark EO showed the most synergistic antimicrobial effect. The combination of the EOs of cinnamon bark/clove and cinnamon bark/cinnamon leaves showed additive effect against L. monocytogenes but indifferent effect against E. coli O157:H7. For L. monocytogenes, the best inhibitory effects were achieved by cinnamon bark EO (85 ppm)/vanillin (910 ppm) and clove EO (121 ppm)/vanillin (691 ppm) combinations. For E. coli, the inhibitory effects of clove EO (104 ppm)/vanillin (1006 ppm) and cinnamon leaves EO (118 ppm)/vanillin (979 ppm) combinations were noteworthy. Some of the tested combinations increased the antimicrobial effect and would allow the effective doses to be reduced, thereby offering possible new applications for food and active food packaging.


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