In vitro control of post-harvest fruit rot fungi by some plant essential oil components

A Novel Preservative Film with a Pleated Surface Structure and Dual Bioactivity Properties for Application in Strawberry Preservation due to Its Efficient Apoptosis of Pathogenic Fungal Cells

Botrytis cinerea (B. cinerea) and Colletotrichum gloeosporioides (C. gloeosporioides) were isolated from the decaying strawberry tissue. The antifungal properties of Monarda didyma essential oil (MEO) and its nanoemulsion were confirmed, demonstrating complete inhibition of the pathogens at concentrations of 0.45 μL/mL (0.37 mg/mL) and 10 μL/mL, respectively. Thymol, a primary component of MEO, was determined as an antimicrobial agent with IC50 values of 34.51 (B. cinerea) and 53.40 (C. gloeosporioides) μg/mL. Hippophae rhamnoides oil (HEO) was confirmed as a potent antioxidant, leading to the development of a thymol-HEO-chitosan film designed to act as an antistaling agent. The disease index and weight loss rate can be reduced by 90 and 60%, respectively, with nutrients also being well-preserved, offering an innovative approach to preservative development. Studies on the antifungal mechanism revealed that thymol could bind to FKS1 to disrupt the cell wall, causing the collapse of mitochondrial membrane potential and a burst of reactive oxygen species.

Antimicrobial, anti-enzymatic and antioxidant activities of essential oils from some Tunisian Eucalyptus species

Many plants can produce essential oils (EOs), having various biological properties. This study evaluated the antioxidant, anti-enzymatic and antimicrobial effects of the EOs derived from leaves of Eucalyptus cladocalyx, E. angulosa, E. microcorys, E. ovata, E. diversicolor, E. saligna, E. sargentii and E. resinifera. The antioxidant activity of the EOs was carried out with three different methods (ABTS, DPPH and FRAP). In addition, their anti-colinesterases, anti α-amylase and anti α-glucosidase effects were assessed by spectrophotometric assays. The antimicrobial activities were tested against six phytopathogenic bacterial strains, including two G + ve (Bacillus mojavensis and Clavibacter michiganensis) and four G-ve (Pseudomonas fluorescence, P. syringae, Xanthomonas campestris and E. coli). The current study has also investigated the inhibition of biofilm formation and the possible effect on bacterial cells biofilm metabolism of three Gram-negative (Pseudomonas aeruginosa, Escherichia coli and Acinetobacter baumannii) and two Gram-positive pathogenic bacteria (Staphylococcus aureus and Listeria monocytogenes). The ABTS and DPPH tests indicated that E. diversicolor and E. saligna EOs showed high antioxidant activities, whereas FRAP test suggested that E. diversicolor EO exhibited the better antioxidant activity. E. resinifera and E. ovata EOs were the most active against cholinesterases instead E. ovata and E. sargentii EOs were more active against enzymes involved in diabetes. Antibacterial assays revealed that E. ovata and E. saligna EOs possess significant activity closely to tetracycline. Whereas, the antifungal assay revealed that all EOs have effectively suppressed the tested fungal growth. E. saligna EO showed substantial efficacy inhibiting both the mature biofilm (85.40 %) and metabolic activities (89.80 %) of L. monocytogenes. These results demonstrate the wide range of possible uses for Eucalyptus EOs in both agriculture and medicine fields, suggesting potential uses as strong antibiofilm agents and for biocontrol of phytopathogens.

Anti-oomycete activities from essential oils and their major compounds on Phytophthora infestans

Botanicals are various plant-based products like plant extracts or essential oils. Anti-fungal activities of selected essential oils were tested on the pathogen causing potato and tomato late blight (Phytophthora infestans). Tests to evaluate anti-oomycete activities of commercial essential oils and their major compounds were carried out in vitro in microplate in liquid media. Anti-oomycete activities on Phytophthora infestans strain were obtained from essential oils/major compounds: Eucalyptus citriodora/citronellal; Syzygium aromaticum (clove)/eugenol; Mentha spicata/D-Carvone, L-Carvone; Origanum compactum/carvacrol; Satureja montana (savory)/carvacrol; Melaleuca alternifolia (tea tree)/terpinen-4-ol, and Thymus vulgaris/thymol. As an active substance of mineral origin, copper sulfate was chosen as a control. All selected essential oils showed an anti-oomycete activity calculated with IC50 indicator. The essential oils of clove, savory, and thyme showed the best anti-oomycete activities similar to copper sulfate, while oregano, eucalyptus, mint, and tea tree essential oils exhibited significantly weaker activities than copper sulfate. Clove essential oil showed the best activity (IC50 = 28 mg/L), while tea tree essential oil showed the worst activity (IC50 = 476 mg/L). For major compounds, three results were obtained: they were statistically more active than their essential oils (carvacrol for oregano, D- and L-Carvone for mint) or as active as their essential oils sources (thymol for thyme, carvacrol for savory, terpinen-4-ol for tea tree) or less active than their original essential oils (eugenol for clove, citronellal for eucalyptus). Microscopical observations carried out with the seven essential oils showed that they were all responsible for a modification of the morphology of the mycelium. The results demonstrated that various essential oils show different anti-oomycete activities, sometimes related to a major compound and sometimes unrelated, indicating that other compounds must play a role in total anti-oomycete activity.

Thymol Edible Coating Controls Postharvest Anthracnose by Regulating the Synthesis Pathway of Okra Lignin

Okra has received extensive attention due to its high nutritional value and remarkable functional characteristics, but postharvest diseases have severely limited its application. It is important to further explore the methods and potential methods to control the postharvest diseases of okra. In this study, Colletotrichum fioriniae is the major pathogen that causes okra anthracnose, which can be isolated from naturally decaying okra. The pathogenicity of C. fioriniae against okra was preliminarily verified, and the related biological characteristics were explored. At the same time, an observational study was conducted to investigate the in vitro antifungal effect of thymol edible coating (TKL) on C. fioriniae. After culturing at 28 °C for 5 days, it was found that TKL showed an obvious growth inhibition effect on C. fioriniae. The concentration for 50% of the maximal effect was 95.10 mg/L, and the minimum inhibitory concentration was 1000 mg/L. In addition, it was found that thymol edible coating with a thymol concentration of 100 mg/L (TKL100) may cause different degrees of damage to the cell membrane, cell wall, and metabolism of C. fioriniae, thereby inhibiting the growth of hyphae and causing hyphal rupture. Refer to the results of the in vitro bacteriostatic experiment. Furthermore, the okra was sprayed with TKL100. It was found that the TKL100 coating could significantly inhibit the infection of C. fioriniae to okra, reduce the rate of brown spots and fold on the okra surface, and inhibit mycelium growth. In addition, the contents of total phenols and flavonoids of okra treated with TKL100 were higher than those of the control group. Meanwhile, the activities of phenylalaninammo-nialyase, cinnamic acid-4-hydroxylase, and 4-coumarate-CoA ligase in the lignin synthesis pathway were generally increased, especially after 6 days in a 28 °C incubator. The lignin content of TKL-W was the highest, reaching 65.62 ± 0.68 mg/g, which was 2.24 times of that of CK-W. Therefore, TKL may promote the synthesis of total phenols and flavonoids in okra, then stimulate the activity of key enzymes in the lignin synthesis pathway, and finally regulate the synthesis of lignin in okra. Thus, TKL could have a certain controlling effect on okra anthracnose.

A combination of cinnamaldehyde and citral greatly alleviates postharvest occurrence of sour rot in citrus fruits without compromising the fruit quality

One of the most troublesome postharvest diseases of citrus fruits is sour rot, caused by Geotrichum citri-aurantii. Sour rot reduces the shelf life of the fruits leading to massive economic losses. This study investigated the potential for a combination of cinnamaldehyde and citral (CC; 1: 2, v/v) at reducing the incidence of sour rot postharvest and its possible effect on fruit quality. Our findings show that CC could totally inhibit germination of G. citri-aurantii spores, with the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) both being 0.80 mL L^-1. The combination (CC) acted against G. citri-aurantii by targeting the chitin content of the cell wall. Wax + CC (WCC; 1 × MFC) treatment also showed high efficiency in reducing the incidence of sour rot, which was 40% lower than in the control group by day 8 when all the fruits in the latter were rotten. Apart from vitamin c (Vc) content which was higher in the test group than in the control group, WCC treatment did not have any significant effect on the quality of the citrus fruits, the examined fruit quality parameters being weight loss rate, coloration index, firmness, pH, total soluble solid (TSS) content, Vc content, as well as solid acid ratio. These results indicate that the combination of cinnamaldehyde and citral (CC, 1: 2, v/v) can be used as a natural preservative to alleviate the progress of sour rot in citrus fruits postharvest.

The Chemistry of Antibiofilm Phytocompounds

Phytocompounds are long known for their therapeutic uses due to their competence as antimicrobial agents. The antimicrobial activity of these bioactive compounds manifests their ability as an antibiofilm agent and is thereby proved to be competent to treat the widespread biofilm-associated chronic infections. The rapid development of antibiotic resistance in bacteria has made the treatment of these infections almost impossible by conventional antibiotic therapy, which forced a switch-over to the use of phytocompounds. The present overview deals with the classification of a huge array of phytocompounds according to their chemical nature, detection of their target pathogen, and elucidation of their mode of action.

Chemical composition and antifungal activity of essential oil from Origanum vulgare against Botrytis cinerea

In this study, the chemical composition of the essential oil (EO) of Origanum vulgare was characterized, and the antifungal activity of the EO and some individual components against Botrytis cinerea (Y-BC-1) was determined. Twenty-one components were identified by gas chromatography-mass spectrometry and gas chromatography-flame ionization detection, constituting 95.7% of the EO. The major components were methyleugenol (16.5%), myristicin (15.6%), carvacrol (15.0%), thymol (9.8%), apioline (9.4%), and (Z)-β-farnesene (8.7%). B. cinerea in vitro mycelial growth and spore germination were strongly inhibited by the EO and two of its main components, thymol and carvacrol. In vivo vapor contact assays, the antifungal activity of the EO at 250 mg/L suppressed the decay of cherry tomatoes 96.39%. Moreover, thymol and carvacrol at 125 mg/L completely suppressed the gray mold. Thus, the EO of O. vulgare is a potentially nontoxic and ecofriendly botanical fungicide for postharvest control of gray mold.

Post-Harvest Enhancing and Botrytis cinerea Control of Strawberry Fruits Using Low Cost and Eco-Friendly Natural Oils

This work investigates an experimental study for using low-cost and eco-friendly oils to increase the shelf life of strawberry fruit. Three natural oils were used: (i) Eucalyptus camaldulensis var obtuse, (ii) Mentha piperita green aerial parts essential oils (EOs), and (iii) Moringa oleifera seeds n-hexane fixed oil (FO). Furthermore, a mixture of EOs from E. camaldulensis var obtusa and M. piperita (1/1 v/v) was used. The treated fruits were stored at 5 °C and 90% relative humidity (RH) for 18 days. HPLC was used to analyse the changes in phenolic compounds during the storage periods. The effects of biofumigation through a slow-release diffuser of EOs (E. camaldulensis var obtusa and M. piperita), or by coating with M. oleifera FO, were evaluated in terms of control of post-harvest visual and chemical quality of strawberry fruits. The post-harvest resistance of strawberry fruits to Botrytis cinerea fungal infection was also evaluated. As a result, the EO treatments significantly reduced the change in visual and chemical quality of strawberry fruit. Additionally, changes in the titratable acidity of moringa FO-coated strawberry fruits were delayed. EO treatments improved total soluble solids, total phenols, ascorbic acid, antioxidants and peroxidase. E. camaldulensis var obtusa and M. piperita (1/1 v/v) EO-vapour fruit exhibited a slower rate of deterioration, compared to other treatments in all tested, in two experiments. The lowest colour change (ΔE) was observed inthe fruit treated with E. camaldulensis var obtusa EO and M. oleifera FO. HPLC showed changes in phenolic compounds’ concentration, where p-coumaric acid, caffeic acid, gallic acid, ferulic acid and ellagic acid were mostly identified in the fruits treated with the oils. SEM examination confirmed the potential decrease in fungal growth as the fruits were treated with EOs. In conclusion, the treatment of EOs during different storage periods showed promising characterisations for strawberry fruit quality.

Antifungal Polyvinyl Alcohol Coatings Incorporating Carvacrol for the Postharvest Preservation of Golden Delicious Apple

Different polyvinyl alcohol (PVA) coating formulations incorporating starch (S) and carvacrol (C) as the active agent were applied to Golden Delicious apples to evaluate their effectiveness at controlling weight loss, respiration rate, fruit firmness, and fungal decay against B. cinerea and P. expansum throughout storage time. Moreover, the impact of these coatings on the sensory attributes of the fruit was also analyzed. The application of the coatings did not notably affect the weight loss, firmness changes, or respiration pathway of apples, probably due to the low solid surface density of the coatings. Nevertheless, they exhibited a highly efficient disease control against both black and green mold growths, as a function of the carvacrol content and distribution in the films. The sensory analysis revealed the great persistence of the carvacrol aroma and flavor in the coated samples, which negatively impact the acceptability of the coated products.

Unravelling the Antifungal Effect of Red Thyme Oil (Thymus vulgaris L.) Compounds in Vapor Phase

The aim of this work was to evaluate the antifungal activity in vapor phase of thymol, p-cymene, and γ-terpinene, the red thyme essential oil compounds (RTOCs). The Minimum Inhibitory Concentration (MIC) of RTOCs was determined against postharvest spoilage fungi of the genera Botrytis, Penicillium, Alternaria, and Monilinia, by measuring the reduction of the fungal biomass after exposure for 72 h at 25 °C. Thymol showed the lowest MIC (7.0 µg/L), followed by γ-terpinene (28.4 µg/L) and p-cymene (40.0 µg/L). In the case of P. digitatum ITEM 9569, resistant to commercial RTO, a better evaluation of interactions among RTOCs was performed using the checkerboard assay and the calculation of the Fractional Inhibitory Concentration Index (FICI). During incubation, changes in the RTOCs concentration were measured by GC-MS analysis. A synergistic effect between thymol (0.013 ± 0.003 L/L) and γ-terpinene (0.990 ± 0.030 L/L) (FICI = 0.50) in binary combinations, and between p-cymene (0.700 ± 0.010 L/L) and γ-terpinene (0.290 ± 0.010 L/L) in presence of thymol (0.008 ± 0.001 L/L) (FICI = 0.19), in ternary combinations was found. The synergistic effect against the strain P. digitatum ITEM 9569 suggests that different combinations among RTOCs could be defined to control fungal strains causing different food spoilage phenomena.

Botrytis cinerea and Table Grapes: A Review of the Main Physical, Chemical, and Bio-Based Control Treatments in Post-Harvest

Consumers highly appreciate table grapes for their pleasant sensory attributes and as good sources of nutritional and functional compounds. This explains the rising market and global interest in this product. Along with other fruits and vegetables, table grapes are considerably perishable post-harvest due to the growth of undesired microorganisms. Among the microbial spoilers, Botrytis cinerea represents a model organism because of its degrading potential and the huge economic losses caused by its infection. The present review provides an overview of the recent primary physical, chemical, and biological control treatments adopted against the development of B. cinerea in table grapes to extend shelf life. These treatments preserve product quality and safety. This article also focuses on the compliance of different approaches with organic and sustainable production processes. Tailored approaches include those that rely on controlled atmosphere and the application of edible coating and packaging, as well as microbial-based activities. These strategies, applied alone or in combination, are among the most promising solutions in order to prolong table grape quality during cold storage. In general, the innovative design of applications dealing with hurdle technologies holds great promise for future improvements.

Antifungal Activity of Volatile Organic Compounds Produced by Bacillus methylotrophicus and Bacillus thuringiensis against Five Common Spoilage Fungi on Loquats

Loquat fruit is one of the most perishable fruits in China, and has a very limited shelf life because of mechanical injury and microbial decay. Due to an increasing concern about human health and environmental security, antagonistic microorganisms have been a potential alternative for fungicides to control postharvest diseases. In this work, the antifungal effect of volatile organic compounds (VOCs) produced by Bacillus methylotrophicus BCN2 and Bacillus thuringiensis BCN10 against five postharvest pathogens isolated from loquat fruit, Fusarium oxysporum, Botryosphaeria sp., Trichoderma atroviride, Colletotrichum gloeosporioides, and Penicillium expansum were evaluated by in vitro and in vivo experiments. As a result, the VOCs released by BCN2 and BCN10 were able to suppress the mycelial growth of all targeted pathogens according to inhibition ratio in the double petri-dish assay as well as disease incidence and disease diameter on loquat fruits. The main volatile compounds were identified by solid-phase microextraction (SPME)-gas chromatography. These VOCs produced by the two strains played complementary roles in controlling these five molds and enabled loquat fruits to keep fresh for ten days, significantly. This research will provide a theoretic foundation and technical support for exploring the functional components of VOCs applicable in loquat fruit preservation.

RESEARCH OF THE BACTERICIDAL PROPERTIES AND TOXICITY OF COMPOSITIONS FOR STONE FRUIT PRESERVATION

Damage of stone fruit during storage begins with the development of mycelial fungi on their surface that destroy the shell of a fruit and its anatomical integrity. Therefore, developing new tools for processing stone fruits on the basis of components harmless to people is a topical task of the modern agricultural, phytochemical, and biological industries. Nine compositions from extracts of medicinal plants and 2% of chitosan have been developed. The raw materials used to obtain extracts were: aloe leaves, camomile inflorescences, spruce bark (in the ratios 4:3:2, 5:4:3, 3:1:2, samples 1, 2, 3, respectively); eucalyptus leaves, basil herbs, thyme herbs (in the ratios 1:2:1, 2:4:3, 2:5:2, samples 4, 5, 6, respectively); lemon balm leaves, sage leaves, verbena grass (in the ratios 3:2:1, 4:3:2, 3:1:1, samples 7, 8, 9, respectively). All the compositions have been tested for fungicidal properties against Monilinia laxa and for antimicrobial activity by the sanitary-bacteriological method, and for toxicity by bacteriological methods (the method of direct inoculation on blood agar and the method of diffusion into agar). In all the samples studied, inhibited growth of the culture of the agent causing stone fruit moniliosis has been detected. All nine compositions have revealed antimicrobial action against Bacillus cereus ATCC 107-02, Escherichia coli ATCC-25922, and Candida albicans ATCC-885-653, with the best results in samples 1, 2, 3, 4, 6, 9. In the study of toxicity by direct inoculation on blood agar, samples 1, 2, 6 caused hemolysis of erythrocytes only in the area of application of the sample. Other samples did not show hemolytic activity. The study has shown that samples 3, 4, 9 are safe for humans, they demonstrate fungicidal properties and antimicrobial action against pathogens of stone fruits, which makes it possible to use them as components of chitosan-based film-forming compositions during storage.

Anti-quorum Sensing and Antimicrobial Effect of Mediterranean Plant Essential Oils Against Phytopathogenic Bacteria

Essential oils (EOs) are one of the most interesting natural products extracted from different aromatic plants. For centuries, EOs have been considered an essential part of the traditional pharmacopeia. Many plant EOs have been reported as possible effective alternatives for commercial pesticides, and their single constituents have been used efficiently in food preservation for their promising anti-QS activity against several food pathogenic microorganisms. The current mini review gives a general overview over the microbicide effect as well as anti-quorum sensing and the anti-biofilm formation of some common plant EOs, especially those of Lamiaceae and Verbanaceae families; these are commonly grown in the Mediterranean region and are effective against some serious food phytopathogenic bacteria.

Effectiveness of nanoemulsions of clove and lemongrass essential oils and their major components against Escherichia coli and Botrytis cinerea

Nanoemulsions exhibit a number of advantages to carry and deliver lipophilic compounds such as essential oils (EOs) due to their good stability and high surface area per volume unit. The purpose of this work was to assess the long-term stability of nanoemulsions of clove and lemongrass (LG) EOs and their principal components eugenol and citral (CI), respectively, at 3 different concentrations (2, 5 or 10 times their respective minimum inhibitory concentrations) and at two storage temperatures (1 °C and 21 °C). The initial droplet size of LG and CI-loaded nanoemulsions was below 100 nm and most of them kept droplet sizes in the nano-range until the end of storage at both temperatures. The ζ-potential was lower than - 40 mV, but it increased through storage, indicating a weaker alginate adsorption at the oil surface at both temperatures. The antimicrobial activity increased with the EOs concentration and was negatively affected by the highest storage temperature. Nanoemulsions containing CI and LG were able to significantly decrease Escherichia coli counts during storage, particularly at 1 °C. Nanoemulsions containing 1.0 and 2.0% w/w CI and 2.5% w/w LG were the most efficient in reducing Botrytis cinerea growth through storage, mainly at 1 °C. The nanoemulsions containing 1.0 and 2.0% w/w CI, as well as, 1.25 and 2.5% w/w LG better maintained their stability and antimicrobial effect along 6-months storage mainly when at 1 °C, making those nanoemulsions suitable as edible coatings for food preservation. Future studies should be oriented to evaluate the impact of these nanoemulsions on the organoleptic properties of coated foods and their potential toxicity.

Chitosan-Based Coating Enriched with Hairy Fig (Ficus hirta Vahl.) Fruit Extract for “Newhall” Navel Orange Preservation

A novel coating based on 1.5% chitosan (CH), enriched with or without hairy fig (Ficus hirta Vahl.) fruit extract (HFE), was applied to “Newhall” navel orange for improving the preservation effect. Changes in physicochemical indexes were analyzed over 120 days of cold storage. Uncoated fruit were used as the control. The CH-HFE coating, based on 1.5% CH enriched with HFE, exhibited the best preservation effect and showed the lowest decay rate (5.2%) and weight loss (5.16%). The CH-HFE coating could postpone the ripening and senescence of navel oranges, and maintain higher fruit quality by inhibiting respiration, decreasing the accumulation of malondialdehyde (MDA), and enhancing the activities of protective enzyme, including superoxide dismutase (SOD), peroxidase (POD), chitinase (CHI), and β-1,3-glucanase (GLU), which suggests that CH-HFE coating has the potential to improve the postharvest quality of “Newhall” navel orange and prolong the storage life.

Effect of Cinnamaldehyde and Citral Combination on Transcriptional Profile, Growth, Oxidative Damage and Patulin Biosynthesis of Penicillium expansum

Penicillium expansum, as a main postharvest pathogen of fruits, can secrete patulin (PAT), causing fruit decay and health problems. In this study, the antifungal test, SEM (scanning electron microscope) observation, transcriptional profile, PAT biosynthesis, and physiological characters of P. expansum exposed to cinnamaldehyde and citral combination (Cin/Cit) were evaluated. Cin/Cit could inhibit the mycelial growth and spore germination of P. expansum in a dose-dependent manner. Besides, Cin/Cit caused spores and mycelia wrinkled and depressed by SEM observation. Gene expression profiles of P. expansum were conducted by RNA sequencing (RNA-seq) in the presence or absence of Cin/Cit treatment. A total of 1713 differentially expressed genes (DEGs) were obtained, including 793 down-regulated and 920 up-regulated genes. Most of the DEGs participated in the biosynthesis of secondary metabolites, amino acid metabolism, and oxidation-reduction process, etc. Cin/Cit induced the dysfunction of the mitochondrial membrane, causing the potential influence on energy metabolism and reactive oxidative species production. The changes of superoxide dismutase (SOD) and catalase (CAT) activities combing with the increase of hydrogen peroxide content indicated the oxidative stress on P. expansum induced by Cin/Cit, which corresponded well with the transcriptional results. Moreover, both the RNA-seq data and the qRT-PCR showed the remarkable down-regulation of genes included in the PAT biosynthetic pathway under the Cin/Cit treatment. These findings provided more useful information about the antifungal mechanism of Cin/Cit against P. expansum at molecular and gene levels and suggested that Cin/Cit is a potential candidate to control P. expansum.

Antifungal mechanism of cinnamaldehyde and citral combination against Penicillium expansum based on FT-IR fingerprint, plasma membrane, oxidative stress and volatile profile

Cinnamaldehyde (Cin) and citral (Cit) have been studied as antimicrobial agents and natural preservatives, but their action modes are controversial, and the knowledge of their antifungal mechanism against P. expansum is still incomplete.

An Overview of the Biological Effects of Some Mediterranean Essential Oils on Human Health

Essential oils (EOs), extracted from aromatic plants, are interesting natural products and represent an important part of the traditional pharmacopeia. The use of some EOs as alternative antimicrobial and pharmaceutical agents has attracted considerable interest recently. Most of the EOs and their single constituents have been reported to inhibit several phytopathogens, human pathogens, and insects as well as their effective uses in food and pharmaceutical industries. The current review discussed the chemical composition and bioactivity of some important EOs extracted from some Mediterranean plants and their principal bioactive single constituents. Information has been furnished on the mechanisms, mode of actions, and factors affecting the bioactivity of some single constituents from different Mediterranean plant EOs. The current review gives an insight into some common plant EOs belonging to Lamiaceae, Apiaceae, Rutaceae, and Verbenaceae families commonly growing in Mediterranean region. Further information has been provided about the medical uses of some EOs for several human diseases covering the pharmacological effects (anti-inflammatory, antioxidant, and anticarcinogenic). The antimicrobial effects have been also considered in the current review. Although plant EOs are considered promising natural alternatives for many chemical drugs, they still need more specific research for wide application especially in food and pharmaceutical industries.

Cytotoxic Activity of Origanum Vulgare L. on Hepatocellular Carcinoma cell Line HepG2 and Evaluation of its Biological Activity

The potential of plant essential oils (EOs) in anticancer treatment has recently received many research efforts to overcome the development of multidrug resistance and their negative side effects. The aims of the current research are to study (i) the cytotoxic effect of the crude EO extracted from Origanum vulgare subsp hirtum and its main constituents (carvacrol, thymol, citral and limonene) on hepatocarcinoma HepG2 and healthy human renal cells HEK293; (ii) the antibacterial and phytotoxic activities of the above EO and its main constituents. Results showed that cell viability percentage of treated HepG2 by EO and its main constituents was significantly decreased when compared to untreated cells. The calculated inhibition concentration (IC₅₀) values for HepG2 were lower than healthy renal cells, indicating the sort of selectivity of the studied substances. Citral is not potentially recommended as an anticancer therapeutic agent, since there are no significant differences between IC₅₀ values against both tested cell lines. Results showed also that oregano EO and its main constituents have a significant antibacterial activity and a moderate phytotoxic effect. The current research verified that oregano EO and its main constituents could be potentially utilized as anticancer therapeutic agents.

Antimicrobial Activity and Chemical Composition of Three Essential Oils Extracted from Mediterranean Aromatic Plants

There is a growing interest in essential oils (EOs) as possible alternatives for traditional chemical pesticides. This study was carried out to characterize the chemical composition of the three EOs extracted from Verbena officinalis, Majorana hortensis, and Salvia officinalis using gas chromatography (GC) and GC-mass spectrometry (GC-MS) and to evaluate in vitro their efficacy against some phyto or human pathogens. The antifungal activity was investigated against Colletotrichum acutatum and Botrytis cinerea in comparison with Azoxystrobin as a large spectrum fungicide. Antibacterial activity was evaluated against Bacillus megaterium, Bacillus mojavensis, and Clavibacter michiganensis (G+ve) and Escherichia coli, Xanthomonas campestris, Pseudomonas savastanoi, and P. syringae pv. phaseolicola (G-ve) compared to a synthetic antibiotic tetracycline. Minimum inhibitory concentration was evaluated against the above tested fungi using 96-well microplate method. Results showed that the chemical structure of the three studied EOs was mainly composed of monoterpene compounds and all oils belong to the chemotype carvacrol/thymol. Results of GC analysis identified 64 compounds, which were identified based on their mass to charge ratio. Furthermore, the different concentrations of studied EOs inhibited the growth of tested microorganism in a dose-dependent manner.

The use of medicinal herbs in gynecological and pregnancy-related disorders by Jordanian women: a review of folkloric practice vs. evidence-based pharmacology

Context National statistical reports in Jordan indicate a decrease in the total fertility rate along with a parallel increase in contraceptive use. The folkloric use of medicinal herbs in gynecological disorders has been growing in Jordan, despite of deficient reports on the evidence-based safety and efficacy of these practices. Objective The aim of this comprehensive article is to review medicinal plants with claimed ethnonpharmacological usage in various gynecological and pregnancy-related issues in Jordan, and to assess their evidence-based pharmacological studies as well as their phytochemistry. Methods The published literature was surveyed using Google Scholar entering the terms "ethnopharmacology AND Jordan AND infertility AND gynecology OR gestation". We included ethnopharmacological surveys in Jordan with available full-text. Results Twelve articles were reviewed. Plant species which are commonly used for female gynecological issues such as Artemisia monosperma Del. and A. herba-alba Asso. (Asteraceae) have been found to exert an antifertility effect. Ricinus communis L. (Euphorbiaceae) and Citrullus colocynthis (L.) Schrad. (Cucurbitaceae) had antifertility effects in male rats, but Nigella sativa oil L. (Ranunculaceae) and Cinnamon zeylanicum J. Presl (Lauraceae) were found to enhance it. Conclusion Using plants for gynecological disorders is a common practice in Jordan. Many of them, whether utilised for gynecological or non-gynecological conditions equally, were found to have detrimental effects on female or male fertility. Thus, couples planning pregnancy should be discouraged from the consumption of these herbs. Further local studies are warranted to confirm the appreciable beneficial pharmacological effects and safety of these plants.

Phytochemical Analysis and Antifungal Activity of Extracts from Leaves and Fruit Residues of Brazilian Savanna Plants Aiming Its Use as Safe Fungicides

The increasing demand for safe food without preservatives or pesticides residues has encouraged several studies on natural products with antifungal activity and low toxicity. In this study, ethanolic extracts from leaves and fruit residues (peel and seeds) of three Brazilian savanna species (Acrocomia aculeata, Campomanesia adamantium and Caryocar brasiliense) were evaluated against phytopathogenic fungi. Additionally, the most active extract was chemically characterized by ESI-MS and its oral acute toxicity was evaluated. Extracts from C. brasiliense (pequi) peel and leaves were active against Alternaria alternata, Alternaria solani and Venturia pirina with minimal inhibitory concentrations between 350 and 1000 µg/mL. When incorporated in solid media, these extracts extended the lag phase of A. alternata and A. solani and reduced the growth rate of A. solani. Pequi peel extract showed better antifungal activity and their ESI-MS analysis revealed the presence of substances widely reported as antifungal such as gallic acid, quinic acid, ellagic acid, glucogalin and corilagin. The oral acute toxicity was relatively low, being considered safe for use as a potential natural fungicide.

An In Vitro Attempt for Controlling Severe Phytopathogens and Human Pathogens Using Essential Oils from Mediterranean Plants of Genus Schinus

Growing concerns about food safety and environmental protection enhanced the need for new and safe plant disease control strategies. The chemical composition of the three essential oils (EOs) extracted from leaves and fruits of Schinus terebinthifolius and leaves of Schinus molle, growing in Tunisia, was studied by GC and GC-MS. In all, 12 compounds were identified. The oils were mainly composed of terpene compounds. α-Pinene, α-phellandrene, and D-limonene were the major constituents. The aim of the current study was to evaluate the in vitro antimicrobial effectiveness of three EOs derived from plants of genus Schinus and extracted from leaves and fruits of S. terebinthifolius and leaves of S. molle. Both antifungal and antibacterial activities of the EOs were examined. The antifungal activity of the studied EOs was investigated against Colletotrichum acutatum and Botrytis cinerea in comparison with the systemic fungicide azoxystrobin used at 0.8 μL mL(-1). The antibacterial activity was evaluated against three strains of Gram-positive (G+ve) bacteria (Bacillus megaterium, Bacillus mojavensis and Clavibacter michiganensis) and four strains of Gram-negative (G-ve) bacteria (Escherichia coli, Xanthomonas campestris, Pseudomonas savastanoi, and Pseudomonas syringae pv. phaseolicola) compared with the synthetic antibiotic tetracycline at a concentration of 1600 μg mL(-1). The minimum inhibitory concentration of the studied EOs has been evaluated against the above microorganisms using the 96-well microplate method. Tested microorganisms exhibited different levels of sensitivity to each tested EO. All investigated EOs reduced the fungal mycelial growth when used at low concentrations from 250 to 1000 ppm and from 2000 to 8000 ppm against C. acutatum and B. cinerea, respectively. Higher concentrations of the same EOs exhibited a fungicidal effect against both mitosporic fungi. The EO extracted from leaves of S. terebinthifolius significantly inhibited the growth of tested bacterial strains. Nevertheless, E. coli showed a weak resistance toward the same EO and a high resistance toward the other two tested EOs. Finally, P. savastanoi and P. syringae pv. phaseolicola showed a high resistance toward all tested EOs.

Application of Volatile Antifungal Plant Essential Oils for Controlling Pepper Fruit Anthracnose by Colletotrichum gloeosporioides

Anthracnose caused by Colletotrichum gloeosporioides has been destructive during pepper fruit production in outdoor fields in Korea. In vitro antifungal activities of 15 different plant essential oils or its components were evaluated during conidial germination and mycelial growth of C. gloeosporioides. In vitro conidial germination was most drastically inhibited by vapour treatments with carvacrol, cinnamon oil, trans-cinnamaldehyde, citral, p-cymene and linalool. Inhibition of the mycelial growth by indirect vapour treatment with essential oils was also demonstrated compared with untreated control. Carvacrol, cinnamon oil, trans-cinnamaldehyde, citral and eugenol were among the most inhibitory plant essential oils by the indirect antifungal efficacies. Plant protection efficacies of the plant essential oils were demonstrated by reduced lesion diameter on the C. gloeosporioides-inoculated immature green pepper fruits compared to the inoculated control fruits without any plant essential oil treatment. In planta test showed that all plant essential oils tested in this study demonstrated plant protection efficacies against pepper fruit anthracnose with similar levels. Thus, application of different plant essential oils can be used for eco-friendly disease management of anthracnose during pepper fruit production.

Secondary metabolites in fungus-plant interactions

Fungi and plants are rich sources of thousands of secondary metabolites. The genetically coded possibilities for secondary metabolite production, the stimuli of the production, and the special phytotoxins basically determine the microscopic fungi-host plant interactions and the pathogenic lifestyle of fungi. The review introduces plant secondary metabolites usually with antifungal effect as well as the importance of signaling molecules in induced systemic resistance and systemic acquired resistance processes. The review also concerns the mimicking of plant effector molecules like auxins, gibberellins and abscisic acid by fungal secondary metabolites that modulate plant growth or even can subvert the plant defense responses such as programmed cell death to gain nutrients for fungal growth and colonization. It also looks through the special secondary metabolite production and host selective toxins of some significant fungal pathogens and the plant response in form of phytoalexin production. New results coming from genome and transcriptional analyses in context of selected fungal pathogens and their hosts are also discussed.

Allium sativum produces terpenes with fungistatic properties in response to infection with Sclerotium cepivorum

This study investigated terpene biosynthesis in different tissues (root, protobulb, leaf sheath and blade) of in vitro-grown garlic plants either infected or not (control) with Sclerotium cepivorum, the causative agent of Allium White Rot disease. The terpenes identified by gas chromatography-electron impact mass spectrometry (GC-EIMS) in infected plants were nerolidol, phytol, squalene, α-pinene, terpinolene, limonene, 1,8-cineole and γ-terpinene, whose levels significantly increased when exposed to the fungus. Consistent with this, an increase in terpene synthase (TPS) activity was measured in infected plants. Among the terpenes identified, nerolidol, α-pinene and terpinolene were the most abundant with antifungal activity against S. cepivorum being assessed in vitro by mycelium growth inhibition. Nerolidol and terpinolene significantly reduced sclerotia production, while α-pinene stimulated it in a concentration-dependent manner. Parallel to fungal growth inhibition, electron microscopy observations established morphological alterations in the hyphae exposed to terpinolene and nerolidol. Differences in hyphal EtBr uptake suggested that one of the antifungal mechanisms of nerolidol and terpinolene might be disruption of fungal membrane integrity.

Comparison of antifungal activities of various essential oils on the Phytophthora drechsleri, the causal agent of fruit decay

BACKGROUND AND OBJECTIVES

The efficacy of Mentha piperita L, Zataria multiflora Boiss and Thymus vulgaris L essential oils (EOs) was evaluated for controlling the growth of Phytophthora drechsleri, the causative agent of damage to many crops that is consumed directly by humans.

MATERIALS AND METHODS

The EOs used in this study was purchased from Magnolia Co, Iran. The pour plate method in petri dishes containing Potato Dextrose Agar (PDA) was used to evaluate the antifungal properties of EOs. The minimal inhibitory concentrations (MIC), minimum fungicidal concentration (MFC) as well as mycelial growth inhibition (MGI) were measured. The IC50 value (the concentration inhibited 50% of the mycelium growth) was calculated by probit analysis.

RESULTS AND CONCLUSION

The fungal growth was significantly reduced by increasing concentrations of tested EOs. The complete reduction was obtained with Shirazi thyme at all concentrations, whereas the complete reduction for peppermint and thyme was observed at 0.4% and 0.8% (v/v) concentrations, respectively. Meanwhile, the minimum inhibition was observed when 0.1% peppermint (MGI values of 9.37%) was used. The IC50, MIC and MFC values of Shirazi thyme was 0.053, 0.1% and 0.2%, respectively. Similarly, MIC and MFC values of peppermint and thyme were recorded 0.4% and 0.8%, respectively. The results obtained from this study may contribute to the development of new antifungal agents to protect the crops from this pathogenic fungus and many agricultural plant pathogens causing drastic crop losses.

Antifungal Activity of Some Constituents of Origanum vulgare L. Essential Oil Against Postharvest Disease of Peach Fruit

Plant essential oils (EOs) can potentially replace synthetic fungicides in the management of postharvest fruit and vegetable diseases. The aim of this study was to evaluate in vitro and in vivo effectiveness of thymol, carvacrol, linalool, and trans-caryophyllene, single constituents of the EO of Origanum vulgare L. ssp. hirtum against Monilinia laxa, M. fructigena, and M. fructicola, which are important phytopathogens and causal agents of brown rot of pome and stone fruits in pre- and postharvest. Moreover, the possible phytotoxic activity of these constituents was assessed and their minimum inhibitory concentration (MIC) was determined. In vitro experiment indicated that thymol and carvacrol possess the highest antifungal activity. Results of in vivo trials confirmed the strong efficacy of thymol and carvacrol against brown rot of peach fruits. The thymol MIC resulted to be 0.16 μg/μL against M. laxa and M. fructigena and 0.12 μg/μL against M. fructicola, whereas for carvacrol they were 0.02 μg/μL against the first two Monilinia species and 0.03 μg/μL against the third. Results of this study indicated that thymol and carvacrol could be used after suitable formulation for controlling postharvest fruit diseases caused by the three studied Monilinia species.

Effects of chitosan-essential oil coatings on safety and quality of fresh blueberries

Chitosan coating plus different essential oils was developed and applied to fresh blueberries in order to find more natural treatments to preserve fresh fruit quality and safety during postharvest storage. Studies were 1st performed in vitro where wild-type Escherichia coli and Penicillium digitatum were grown in suitable media, and then subjected to 6 essential oils. Three compounds, carvacrol (CAR), cinnamaldehyde (CIN), and trans-cinnamaldehyde (ECIN) had high antimicrobial capacity and were selected for an in vivo study for postharvest storage of blueberries. The selected essential oils, 0.5% each, were added into a chitosan solution and coated on fresh blueberries. After storage at 5, 10, and 20 °C for various days, fruit firmness and microbial populations were evaluated. The chitosan coating substantially decreased bacteria and yeasts/molds on the fruit, and all 3 essential oils added to the antimicrobial activities. Further dosage experiments showed that the antimicrobial activity remained even when lowering CAR concentration to 0.1% and ECIN to 0.2%. Chitosan, CAR, and ECIN also maintained fruit firmness. Our results suggest that chitosan coatings containing essential oils are effective in extending the shelf life of fresh blueberries.

PRACTICAL APPLICATION

Blueberries are high-value fruit with strong antioxidant capacity and other health-promoting benefits. However, microbial food safety is an increasing concern, and decay and softening limits their storability. A combination of ≥ 0.1% CAR or ≥ 0.2% ECIN with a chitosan coating effectively reduced softening of fresh berries and decay by inhibiting microbial growth.

Extension of lifespan and protection against oxidative stress by an antioxidant herb mixture complex (KPG-7) in Caenorhabditis elegans

Excessive generation of reactive oxygen species within cells results in oxidative stress. Furthermore, accumulation of reactive oxygen species has been shown to reduce cell longevity. Many dietary supplements are believed to have anti-aging effects. The herb mixture KPG-7 contains several components with antioxidant activity. We aim to clarify the mechanisms responsible for the antioxidant activity of KPG-7 and to establish whether KPG-7 has an anti-aging effect. We examined whether dietary supplementation with KPG-7 could provide protection against oxidative stress, extend lifespan, and delay aging in Caenorhabditis elegans (C. elegans). We found that KPG-7 extended lifespan and delayed aging in adult C. elegans. The expression of oxidation resistance 1 protein was induced by juglone and this effect was significantly suppressed in KPG-7-treated. In addition, the amount of oxidized protein was significantly lower in KPG-7-treated worms than untreated worms. Furthermore, locomotive activity was increased in C. elegans at 3 days of age following the treatment with KPG-7. On the other hand, the level of cellular ATP was lower at 3 days of age in worms treated with KPG-7 than in untreated worms. KPG-7 increases lifespan and delays aging in C. elegans, well corresponding to its activity to protect against oxidative stress.

Antifungal Metabolites Produced by Chaetomium globosum No.04, an Endophytic Fungus Isolated from Ginkgo biloba

The fungal endophyte Chaetomium globosum No.04 was isolated from the medicinal plant Ginkgo biloba. The crude extract of the fungus fermentation were active in the agar-diffusion tests against the phytopathogenic fungi Rhizopus stolonifer and Coniothyrium diplodiella. Further bioassay-guided chemical investigation led to the isolation and purification of six alkaloids and three non-targeted compounds from 50 L fermentation of this endophytic fungus and their structures were elucidated as chaetoglobosin A, C, D, E, G, R (1-6), ergosterol, allantoin and uracil, by means of spectroscopic analysis. Compounds 1-6 showed significant growth inhibitory activity against R. stolonifer and C. diplodiella at a concentration of 20 μg/disc. We present here, for the first time, the potent antifungal activity of chaetoglobosins from endophytic fungi against two important phytopathogenic fungi R. stolonifer and C. diplodiella.