Optimized Antibacterial Effects in a Designed Mixture of Essential Oils of Myrtus communis, Artemisia herba-alba and Thymus serpyllum for Wide Range of Applications

Chemical composition of five essential oils and their antioxidant and in vitro and in vivo antifungal activities against Alternaria alternata in tomato crop

This study aimed to determine the chemical composition of essential oils from A. gratíssima, O. basilicum, S. microphylla, T. riparia, and T. vulgaris and their antioxidant and antifungal activities against Alternaria alternata strains. Gas chromatography-mass spectrometry revealed that the major components of the essential oils were terpenes. The essential oils of S. microphylla and T. riparia showed higher antioxidant activities than the others. The essential oils of S. microphylla and T. riparia inhibited the growth of the fungus at 3.10 and 6.05 µL/mL, respectively. The essential oil of T. riparia inhibited 93.9% of the growth of the fungus and showed the highest in vivo efficiency in severity reduction (76.2%). We conclude that the essential oil of T. riparia shows promising antifungal activity and is an environmentally safe alternative for controlling fungal diseases in vegetables.

Enhancing Antibacterial Efficacy: Synergistic Effects of Citrus aurantium Essential Oil Mixtures against Escherichia coli for Food Preservation

Essential oils (EOs) from various medicinal and aromatic plants are known for their diverse biological activities, including their antimicrobial effects. Citrus aurantium EO is traditionally used for therapeutic benefits due to its high content of bioactive compounds. Therefore, this study focuses on its potential use as a food preservative by investigating the combined antibacterial properties of EOs from leaves (EO1), flowers (EO2), and small branches (EO3) of Citrus aurantium against six bacterial strains by the agar disk diffusion, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) methods. The chemical compositions of the EOs were analysed by gas chromatography-mass spectrometry (GC-MS) and revealed the presence of numerous compounds responsible for their antimicrobial properties. The MIC values for the EOs were 3.12 mg/mL, 4.23 mg/mL, and 1.89 mg/mL, for EO1, EO2 and EO3, respectively, while the MBC values were 12.5 mg/mL, 6.25 mg/mL, and 6.25 mg/mL, respectively. A simplex centroid design was created to analyse the effect of the individual and combined EOs against E. coli. The combined EOs showed enhanced antibacterial activity compared to the individual oils, suggesting a synergistic effect (e.g., trial 9 with an MIC of 0.21 mg/mL), allowing the use of lower EO concentrations and reducing potential negative effects on food flavour and aroma. Additionally, the practical application of investigated EOs (at concentrations twice the MIC) was investigated in raw chicken meat stored at 4 °C for 21 days. The EOs, individually and in combination, effectively extended the shelf life of the meat by inhibiting bacterial growth (total bacterial count of less than 1 × 104 CFU/g in the treated samples compared to 7 × 107 CFU/g in the control on day 21 of storage). The study underlines the potential of C. aurantium EOs as natural preservatives that represent a sustainable and effective alternative to synthetic chemicals in food preservation.

Wild thyme (Thymus serpyllum L.): a review of the current evidence of nutritional and preventive health benefits

Thymus serpyllum L. (Lamiaceae), known in English as 'wild thyme', is primarily found in the Palearctic realm (Eurasia, North Africa) and has been utilized traditionally for culinary, nutritional, medicinal, and aromatic purposes. The essential oil extracted from wild thyme is particularly noteworthy, being used extensively in the food industry as a flavoring agent and preservative. The plant's aerial parts are commonly employed as an element of the diet (e.g., tea)/for culinary uses and in local/traditional medicine (primarily for managing respiratory and gastrointestinal conditions), similar to the use of common thyme. There is practically no information available on the species' nutritional benefits. Pharmacological studies, including in vitro and in vivo research, alongside a limited number of clinical trials, have investigated extracts of Thymus serpyllum, although these extracts are often phytochemically poorly characterized in different experimental protocols and models. These studies have demonstrated a range of therapeutic effects, such as antimicrobial (notably the essential oil) and anti-inflammatory, as well as its preventative health benefits and nutritional value of wild thyme. Preclinical studies have corroborated the plant's anti-inflammatory potential, particularly in conditions like inflammatory bowel diseases (IBD) and irritable bowel syndromes (IBS). Additionally, evidence of hepatoprotective activities and benefits in managing metabolic syndrome and cardiovascular health issues, such as lipid metabolism regulation, cholesterol reduction, antidiabetic, antihypertensive, and immunomodulatory effects, have been observed predominantly in rodent models. Phytochemical analysis of wild thyme reveals an essential oil fraction below 1%, along with non-volatile compounds predominantly comprising phenolic acids (such as rosmarinic, salvianolic, and caffeic acids) and flavonoids (mainly glucosides of luteolin, apigenin, and their derivatives). These components are believed to contribute significantly to the plant's medicinal, nutritional, and preventive health properties. Despite promising findings, there is a need for more rigorously designed controlled clinical trials using phytochemically characterized wild thyme. The plant has an excellent safety and tolerability record. This review at the interface of nutritional/preventive health properties and as pharmacological activities highlights the current role of wild thyme in nutrition and general healthcare as well as its future potential, and also points to important gaps in the literature.

Design of three-component essential oil extract mixture from Cymbopogon flexuosus, Carum carvi, and Acorus calamus with enhanced antioxidant activity

The development of novel antioxidant compounds with high efficacy and low toxicity is of utmost importance in the medicine and food industries. Moreover, with increasing concerns about the safety of synthetic components, scientists are beginning to search for natural sources of antioxidants, especially essential oils (EOs). The combination of EOs may produce a higher scavenging profile than a single oil due to better chemical diversity in the mixture. Therefore, this exploratory study aims to assess the antioxidant activity of three EOs extracted from Cymbopogon flexuosus, Carum carvi, and Acorus calamus in individual and combined forms using the augmented-simplex design methodology. The in vitro antioxidant assays were performed using DPPH and ABTS radical scavenging approaches. The results of the Chromatography Gas-Mass spectrometry (CG-MS) characterization showed that citral (29.62%) and niral (27.32%) are the main components for C. flexuosus, while D-carvone (62.09%) and D-limonene (29.58%) are the most dominant substances in C. carvi. By contrast, β-asarone (69.11%) was identified as the principal component of A. calamus (30.2%). The individual EO exhibits variable scavenging activities against ABTS and DPPH radicals. These effects were enhanced through the mixture of the three EOs. The optimal antioxidant formulation consisted of 20% C. flexuosus, 53% C. carvi, and 27% A. calamus for DPPHIC50. Whereas 17% C. flexuosus, 43% C. carvi, and 40% A. calamus is the best combination leading to the highest scavenging activity against ABTS radical. These findings suggest a new research avenue for EOs combinations to be developed as novel natural formulations useful in food and biopharmaceutical products.

Investigation of Antifungal Action of Fractions C17H31NO15 Isolated from Artemisia herba-alba extract versus Isolated Aspergillus niger from Zee maize

BACKGROUND

Plants are harmed by parasitic organisms, and toxic poisons are created. Phytopathogenic fungi create toxins that can severely harm plants' basic physiological functioning.

OBJECTIVE

Investigation of antifungal impact of various fractions of methanol extract of Artemisia herba-alba to Aspergillus niger as a plant pathogen.

METHODS

Artemisia herba-alba extract was purified using column chromatography, giving various antifungal fractions tested versus A. niger.

RESULTS

The 6th fraction give the highest inhibition zone with a diameter of 5.4 cm and MIC 125.02 ± 4.9 μg/ml, which was identified using Mass spectroscopy, 1HNMR, Elemental analysis as well as IR testing, revealing the chemical formula of the purified fraction. Ultrastructure alteration of treated A. niger was examined versus control using the transmission electron microscope. Purified fraction has tested versus normal cell line with minimal cytotoxicity.

CONCLUSION

These results revealed the possibility of using Artemisia herba-alba methanol extract as a promising antifungal versus phytopathogenic fungi, especially A. niger after more verification of results.

Bioactivities of thymol and p-cymene from the essential oil of Adenosma buchneroides against three stored-product insects

The adverse effects of relying solely on synthetic pesticides have become increasingly evident, leading many countries to explore alternatives sourced from plant-based green economies. Essential oil (EO) from stems and leaves of Adenosma buchneroides Bonati (A. buchneroides) was distilled by using hydrodistillation and subjected to gas chromatography-mass spectrometry (GC-MS) for component identification. Subsequently, EO as well as its main constituents (thymol and p-cymene) were tested for their insecticidal activity against the red flour beetle (Tribolium castaneum), the cigarette beetle (Lasioderma serricorne), and the booklouse (Liposcelis bostrychophila). The joint action of thymol and p-cymene produced an additive or synergistic effect. A. buchneroides essential oil (BHO) and the fixed ratio of the main compounds, thymol, and p-cymene both showed significant toxic activity against the target pests. This toxic effect is not simply the sum of individual effects, as it is influenced by various factors such as insect species and mode of action. These findings imply that the BHO and its phytoconstituents possess great potential to develop plant-derived biopesticides that will be safe for humans and the environment.

Antimicrobial activity in Asterceae: The selected genera characterization and against multidrug resistance bacteria

Plants from the Asteraceae family are widely used as ethno medicines to treatment parasitic, malaria, hematemesis, pruritus, pyretic, anthelmintic, wound healing. The aim of this review is to provide an overview of Asteraceae plants antimicrobial activity. The most relevant results from the published studies are summarized and discussed. The species in genus of Artemisia, Echinacea, Centaurea, Baccharis, and Calendula showed antimicrobial activity. Most of these species are usually used as ethno medicines to treat infection, inflammation, and parasitics. The effective part or component for antimicrobial was essential oil and crude extract, and essential oil attracted more attention. It was also reported that nanoparticles coated with crude extract were effective against multidrug resistant bacteria. For multidrug resistant bacteria study, the species in Armtemisia were the most investigated, and Staphylococcus aureus and Escherichia coli were the most studied multidrug resistant strains. The antimicrobial activity was evaluated mainly based on the results of minimum inhibitory concentration (MIC). Few reports have been reported on minimum bactericide concentration (MBC) and its antibacterial mechanisms. According to the reported study results, some plants in Asteraceae have the potential to be developed as bacteriostatic agents and against multidrug resistant bacteria. However, most studies are still in vitro, further clinical and applied studies are needed.

Electrospun Nanofibers Loaded with Plantago major L. Extract for Potential Use in Cutaneous Wound Healing

Plantago major L. is a plant available worldwide that has been traditionally used for several medical applications due to its wound healing, anti-inflammatory, and antimicrobial properties. This work aimed to develop and evaluate a nanostructured PCL electrospun dressing with P. major extract encapsulated in nanofibers for applications in wound healing. The extract from leaves was obtained by extraction in a mixture of water:ethanol = 1:1. The freeze-dried extract presented a minimum inhibitory concentration (MIC) for Staphylococcus Aureus susceptible and resistant to methicillin of 5.3 mg/mL, a high antioxidant capacity, but a low content of total flavonoids. Electrospun mats without defects were successfully produced using two P. major extract concentrations based on the MIC value. The extract incorporation in PCL nanofibers was confirmed using FTIR and contact angle measurements. The PCL/P. major extract was evaluated using DSC and TGA demonstrating that the incorporation of the extract decreases the thermal stability of the mats as well as the degree of crystallinity of PCL-based fibers. The P. major extract incorporation on electrospun mats produced a significant swelling degree (more than 400%) and increased the capacity of adsorbing wound exudates and moisture, important characteristics for skin healing. The extract-controlled release evaluated using in vitro study in PBS (pH, 7.4) shows that the P. major extract delivery from the mats occurs in the first 24 h, demonstrating their potential capacity to be used in wound healing.

Optimization of a New Antioxidant Formulation Using a Simplex Lattice Mixture Design of Apium graveolens L., Coriandrum sativum L., and Petroselinum crispum M. Grown in Northern Morocco

A statistical Simplex Lattice Mixture design was applied to develop a new formulation based on a combination of three plants grown in northern Morocco: Apium graveolens L., Coriandrum sativum L., and Petroselinum crispum M. We examined the extraction yield, total polyphenol content (TPC), 2'2-diphenyl-l-picrylhydrazyl (DPPH) radical scavenging activity, and total antioxidant capacity (TAC). The results of this screening study showed that C. sativum L. had the highest content of DPPH (53.22%) and TAC (37.46 ± 0.29 mg Eq AA/g DW) compared to the other two plants, while P. crispum M. showed the highest TPC (18.52 ± 0.32 mg Eq GA/g DW). Furthermore, the ANOVA analysis of the mixture design showed that all three responses (DPPH, TAC, and TPC) were statistically significant, with determination coefficients of 97%, 93%, and 91%, respectively, and fit the cubic model. Moreover, the diagnostic plots showed good correlation between the experimental and predicted values. Therefore, the best combination obtained under optimal conditions (P1 = 0.611, P2 = 0.289, P3 = 0.100) was characterized by DPPH, TAC, and TPC of 56.21%, 72.74 mg Eq AA/g DW, and 21.98 mg Eq GA/g DW, respectively. The results of this study reinforce the view of stimulating the effect of plant combinations to achieve better antioxidant activities, thus providing a better formulation using designs of mixtures for the food industry and in cosmetic and pharmaceutical applications. Moreover, our findings support the traditional use of the Apiaceae plant species in managing many disorders cited in the Moroccan pharmacopeia.

Synergistic Antioxidant Activity of Four—Component Mixture of Essential Oils: Basil, Cedarwood, Citronella and Thyme for the Use as Medicinal and Food Ingredient

Mixture design is a statistical tool used to obtain the maximum desired effect using the minimum number of experiments. The aim of the presented work was the optimization of the composition of a mixture of essential oils from basil, citronella, cedarwood and thyme using simplex-lattice mixture design method. The optimized parameter was an antioxidant activity measured in DPPH assay and expressed as effective concentration (EC50). The test results showed an interesting synergy between the components of essential oils. The prepared binary and quaternary mixtures were characterized by higher activity than simple average activity. The designed mixture with approximated highest antioxidant activity was composed of: 54.4% citronella essential oil, 33.0% thyme essential oil, 9.2% cedarwood essential oil and 3.4% basil essential oil and its approximated activity was in agreement with experimental values. This work confirmed that it is possible to approximate the best antioxidant composition of four essential oils used as a potential medicinal and food ingredient.

Family Myrtaceae: The treasure hidden in the complex/diverse composition

Myrtaceae is one of the most important plants families, being regarded as the eighth largest flowering plant family. It includes many genera of utmost ecological and economical importance distributed all over the world. This review aimed to report the latest studies on this family focusing on certain widely used plants including Eucalyptus sp., Eugenia sp. (Eugenia uniflora, Eugenia sulcata), Syzygium sp. (Syzygium aromaticum and Syzygium cumini), Psidium sp., Pimenta dioica, Myrtus sp. (Myrtus communis), Myrciaria sp. and Melaleuca alternifolia. The extraction of bioactive compounds has been evolving through the optimization of conventional methods and the use of emerging technologies. Supercritical CO2 was applied for essential oils and ultrasound for polyphenols leading to extracts and essential oils rich in bioactive compounds. Advances in the field of encapsulation and delivery systems showed promising results in the production of stable essential oils nanoemulsions and liposomes and the production of plant extracts in the form of nanoparticles. Moreover, a significant increase in the number of patents was noticed especially the application of Myrtaceae extracts in the pharrmacuetucal field. The applications of ceratin plants (Pimenta dioica, Melaleuca alternifolia, Syzygium aromaticum essential oils or Myrciaria cauliflora peel extract) in food area (either as a free or encapsulated form) also showed interesting results in limiting microbial spoilage of fresh meat and fish, slowing oxidative degradation in meat products, and inhibiting aflatoxin production in maize. Despite the massive literature on Myrtaceae plants, advances are still necessary to optimize the extraction with environmentally friendly technologies and carry out risk assessment studies should be accomplished to harness the full potential in food, industrial and pharmaceutical applications.

Application of essential oils as natural biopesticides; recent advances

There is an urgent need for the development of sustainable and eco-friendly pesticide formulations since common synthetic pesticides result in many adverse effects on human health and the environment. Essential oils (EOs) are a mixture of volatile oils produced as a secondary metabolite in medicinal plants, and show activities against pests, insects, and pathogenic fungi. Their chemical composition is affected by several factors such as plant species or cultivar, geographical origin, environmental conditions, agricultural practices, and extraction method. The growing number of studies related to the herbicidal, insecticidal, acaricidal, nematicidal, and antimicrobial effects of EOs demonstrate their effectiveness and suitability as sustainable and environment-friendly biopesticides. EOs can biodegrade into nontoxic compounds; at the same time, their harmful and detrimental effects on non-target organisms are low. However, few biopesticide formulations based on EOs have been turned into commercial practice upto day. Several challenges including the reduced stability and efficiency of EOs under environmental conditions need to be addressed before EOs are widely applied as commercial biopesticides. This work is an overview of the current research on the application of EOs as biopesticides. Findings of recent studies focusing on the challenges related to the use of EOs as biopesticides are also discussed.

The effect of essential oils mixture on chitosan-based film surface energy and antiadhesion activity against foodborne bacteria

In the food sector, the formation of biofilms as a result of microbial adherence on food-grade surfaces causes a major problem resulting in significant economic losses. Thereby, this work aimed to elaborate a biodegradable film using chitosan (CS-film) and reinforce its antiadhesion activity by incorporating pelargonium, clove, thyme, and cinnamon essential oils (EOs). Firstly, the antibacterial activity of these EOs alone and combined against four foodborne bacteria were analyzed by the microdilution method. Synergism was observed in the case of EOs combination. Secondly, the physicochemical characteristics and antiadhesion behavior of the CS-films were assessed by the contact angle method and ESEM, respectively. Results revealed that the EOs mixture treatment impacted considerably the physicochemical characteristics of the CS-film and reduced its qualitative and quantitative hydrophobicity. Moreover, the treated CS-film showed a strong antiadhesion behavior against Enterococcus hirae, Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus with percentages of non-covered surface equal to 97.65 ± 1.43%, 98.76 ± 0.32%, 99.68 ± 0.28%, and 95.63 ± 1.32% respectively. From all these results, the CS-film treated with the mixture of EOs presents a great potential for application as surface coating and food packaging preventing microbial adhesion and thus, avoiding food contamination and spoilage.