scholarly journals Peer Review #2 of "Effects of Origanum vulgare essential oil and its two main components, carvacrol and thymol, on the plant pathogen Botrytis cinerea (v0.1)"

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9626
Author(s):  
Huiyu Hou ◽  
Xueying Zhang ◽  
Te Zhao ◽  
Lin Zhou

Background Botrytis cinerea causes serious gray mold disease in many plants. This pathogen has developed resistance to many fungicides. Thus, it has become necessary to look for new safe yet effective compounds against B. cinerea. Methods Essential oils (EOs) from 17 plant species were assayed against B. cinerea, of which Origanum vulgare essential oil (OVEO) showed strong antifungal activity, and accordingly its main components were detected by GC/MS. Further study was conducted on the effects of OVEO, carvacrol and thymol in vitro on mycelium growth and spore germination, mycelium morphology, leakages of cytoplasmic contents, mitochondrial injury and accumulation of reactive oxygen species (ROS) of B. cinerea. The control efficacies of OVEO, carvacrol and thymol on tomato gray mold were evaluated in vivo. Results Of all the 17 plant EOs tested, Cinnamomum cassia, Litsea cubeba var. formosana and O. vulgare EOs had the best inhibitory effect on B. cinerea, with 0.5 mg/mL completely inhibiting the mycelium growth of B. cinerea. Twenty-one different compounds of OVEO were identified by gas chromatography–mass spectrometry, and the main chemical components were carvacrol (89.98%), β-caryophyllene (3.34%), thymol (2.39%), α-humulene (1.38%) and 1-methyl-2-propan-2-ylbenzene isopropyl benzene (1.36%). In vitro experiment showed EC50 values of OVEO, carvacrol and thymol were 140.04, 9.09 and 21.32 μg/mL, respectively. Carvacrol and thymol completely inhibited the spore germination of B. cinerea at the concentration of 300 μg/mL while the inhibition rate of OVEO was 80.03%. EC50 of carvacrol and thymol have significantly (P < 0.05) reduced the fresh and dry weight of mycelia. The collapse and damage on B. cinerea mycelia treated with 40 μg/mL of carvacrol and thymol was examined by scanning electron microscope (SEM). Through extracellular conductivity test and fluorescence microscope observation, it was found that carvacrol and thymol led to increase the permeability of target cells, the destruction of mitochondrial membrane and ROS accumulation. In vivo conditions, 1000 μg/mL carvacrol had the best protective and therapeutic effects on tomato gray mold (77.98% and 28.04%, respectively), and the protective effect was significantly higher than that of 400 μg/mL pyrimethanil (43.15%). While the therapeutic and protective effects of 1,000 μg/mL OVEO and thymol were comparable to chemical control. Conclusions OVEO showed moderate antifungal activity, whereas its main components carvacrol and thymol have great application potential as natural fungicides or lead compounds for commercial fungicides in preventing and controlling plant diseases caused by B. cinerea.


2021 ◽  
pp. 130506
Author(s):  
Yun Zhao ◽  
Yun-Hai Yang ◽  
Min Ye ◽  
Kai-Bo Wang ◽  
Li-Ming Fan ◽  
...  

Author(s):  
E.F. Myagkikh ◽  
◽  
I.N. Korotkikh ◽  

The purpose of the research is a comparative study of the Origanum vulgare L. varieties ‘Raduga’, ‘Zima’, ‘Slavnitsa’ bred in the FSBSI All-Russian Scientific Research Institute of Medicinal and Aromatic Plants (VILAR) according to morphological and biological characteristics and economically valuable traits under conditions of the Foothill zone of the Crimea. The productivity of the aforementioned varieties amounted to 1.05±0.2–1.90±0.3 kg/m2; mass fraction of essential oil – 0.04±0.06–0.06±0.24 % of fresh weight and 0.10 ±0.55–0.17±0.61% of absolutely dry weight; essential oil collection – 0.4–0.9 g/m2. Germacrene D (18.4–19.5%) and β-caryophyllene (18.8–27.0%) are the main components of the essential oil collected from some varieties of Origanum vulgare L.


Plants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1174 ◽  
Author(s):  
Edoardo Napoli ◽  
Antonio Giovino ◽  
Alessandra Carrubba ◽  
Vandana How Yuen Siong ◽  
Carmelo Rinoldo ◽  
...  

Oregano is—probably—the most appreciated and widespread aromatic plant in Sicily. With the aim of evaluating the modifications of oregano’s essential oil composition over time, between 2013 and 2015 six weekly samplings of three different oregano plantations were carried out, from the beginning of flowering (early May) until the traditional harvest moment (end of June). Samples were hydrodistilled and the obtained essential oils (EOs) were evaluated by means of a combination of GC–FID and GC–MS. The Origanum plants under study were demonstrated to belong to the high-yielding, thymol-type biotypes, with thymol, γ-terpinene and p-cymene as three main components, among the total of about 50 of the evaluated EOs. In each location, EO yields were found to increase throughout survey dates. Significant variations were found in many EO components, both across years and throughout harvest dates within locations. The choice of the harvest moment was confirmed to be crucial in assessing quality aspects of oregano.


Planta Medica ◽  
2007 ◽  
Vol 73 (09) ◽  
Author(s):  
A Raal ◽  
E Arak ◽  
A Orav

2018 ◽  
Vol 69 (8) ◽  
pp. 1927-1933 ◽  
Author(s):  
Mariana Deleanu ◽  
Elisabeta E. Popa ◽  
Mona E. Popa

The compounds in Ginger (Zingiber officinale-Roscoe) essential oil provenience China and wild oregano (Origanum vulgare) essential oil of Romanian origin were identified by GC/MS and their antioxidant and antifungal properties were evaluated. Wild oregano oil was characterized by high content of oxygenated monoterpenes hydrocarbons (84.05%) of which carvacrol was the most abundant (73.85%) followed by b-linalool (3.46%) and thymol (2.29%). Ginger oil had a higher content of sesquiterpene hydrocarbons including zingiberene (31.47%), b-sesquiphellandrene (13.76%), a-curcumene (10.41%), a-farnesene (8.31%) and b-bisabolene (7.55%) but a lower content of oxygenated monoterpenes (7.97%). The high content of oxygenated monoterpens of wild oregano oil is in accordance with total content of polyphenols determined by the Folin�Ciocalteu method (6.71�0.73 mg of gallic acid equivalent per g oil). Ginger oil had only 1.34�0.22 mg gallic acid equivalent per g oil. Wild oregano oils exhibited appreciable in vitro antioxidant activity as assessed by 2, 2`-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and 2,2�-azino-bis (3 ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS). The sample concentration required to scavenge 50% of the DPPH free radicals was 0.76�0.13 mg/mL for wild oregano oil compared to 20.22�2.12 mg/mL for ginger oil. Also, wild oregano oils showed significant inhibitory activity against selected pathogenic fungi (Fusarium oxysporum, Aspergillus flavus and Penicillium expansum). 1�L of oregano oil is sufficient for almost 75% growth inhibition of Aspergillus flavus compared to ginger oil which shows antifungal activity at 240�L for 78% growth inhibition. It can be concluded that wild oregano oil could be used as food preservative in some food products in which Fusarium oxysporum, Aspergillus flavus and Penicillium expansum could grow and have potential to produce health hazards mycotoxines.


Pathogens ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 192 ◽  
Author(s):  
Sanae Akkaoui ◽  
Anders Johansson ◽  
Maâmar Yagoubi ◽  
Dorte Haubek ◽  
Adnane El hamidi ◽  
...  

In this study, the essential oil of Origanum vulgare was evaluated for putative antibacterial activity against six clinical strains and five reference strains of Aggregatibacter actinomycetemcomitans, in comparison with some antimicrobials. The chemical composition of the essential oil was analyzed, using chromatography (CG) and gas chromatography–mass spectrometry coupled (CG–MS). The major compounds in the oil were Carvacrol (32.36%), α-terpineol (16.70%), p-cymene (16.24%), and Thymol (12.05%). The antimicrobial activity was determined by an agar well diffusion test. A broth microdilution method was used to study the minimal inhibitory concentration (MIC). The minimal bactericidal concentration (MBC) was also determined. The cytotoxicity of the essential oil (IC50) was <125 µg/mL for THP-1 cells, which was high in comparison with different MIC values for the A. actinomycetemcomitans strains. O. vulgare essential oil did not interfere with the neutralizing capacity of Psidium guajava against the A. actinomycetemcomitans leukotoxin. In addition, it was shown that the O. vulgare EO had an antibacterial effect against A. actinomycetemcomitans on a similar level as some tested antimicrobials. In view of these findings, we suggest that O.vulgare EO may be used as an adjuvant for prevention and treatment of periodontal diseases associated to A. actinomycetemcomitans. In addition, it can be used together with the previously tested leukotoxin neutralizing Psidium guajava.


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