Comparison of Chemical Composition, Antioxidant and Antimicrobial Activity of Lavender (Lavandula angustifolia L.) Essential Oils Extracted by Supercritical CO2, Hexane and Hydrodistillation

Comparative Study on the Chemical Composition and Biological Activities of the Essential Oils of Lavandula angustifolia and Lavandula x intermedia Cultivated in Lebanon

The phytochemical profile of essential oils is influenced by genetic and paragenetic factors. In this research, we studied the essential oils of Lavandula angustifolia and Lavandula x intermedia cultivated in Lebanon. The latter is a cross hybrid between Lavandula angustifolia and Lavandula latifolia and is also known as lavandin and Lavandula hybrida. Specifically, the chemical composition and biological activities (antibacterial, antioxidant, anticancer, and hemolytic) of the essential oils were assessed. GC-MS results showed marked differences in the chemical compositions of the oils. For example, linalool was more abundant in L. x intermedia (44.15%) than in L. angustifolia (32%), while an opposite trend was observed for the percentages of 1,8-cineole (8.6% in L. angustifolia and 4.0% in L. x intermedia). FTIR analysis confirmed the richness of both oils in monoterpenes and sesquiterpenes. In terms of antioxidant activity, L. angustifolia essential oil demonstrated significantly better activity (IC50= 5.24 ± 1.20 mg/mL) compared to L. x intermedia oil in the DPPH radical scavenging assay. MTT cell viability assays revealed that L. angustifolia essential oil was a slightly more potent antiproliferative agent than L. x intermedia oil on human colorectal (HCT-116) and human breast (MCF-7) cancer cells. The antibacterial activity of the essential oils was tested against Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Escherichia coli, and Serratia marcescens. Both oils showed good antibacterial activities with MIC values of 0.174 and 0.169 mg/mL for L. angustifolia and L. x intermedia oils, respectively. MBC determinations revealed that the antibacterial activity was bactericidal against all bacteria, except Staphylococcus aureus. Furthermore, both essential oils did not exhibit notable hemolytic activity on red blood cells. Overall, Lebanese L. angustifolia and L. x intermedia essential oils have promising industrial and medicinal values.

Flower Power: An Overview on Chemistry and Biological Impact of Selected Essential Oils from Blossoms

Natural raw materials such as essential oils have received more and more attention in recent decades, whether in the food industry, as flavorings and preservatives, or as insecticides and insect repellents. They are, furthermore, very popular as fragrances in perfumes, cosmetics, and household products. In addition, aromatherapy is widely used to complement conventional medicine. This review summarizes investigations on the chemical composition and the most important biological impacts of essential oils and volatile compounds extracted from selected aromatic blossoms, including Lavandula angustifolia, Matricaria recutita, Rosa x damascena, Jasminum grandiflorum, Citrus x aurantium, Cananga odorata, and Michelia alba. The literature was collected from PubMed, Google Scholar, and Science Direct. Blossom essential oils discussed in this work are used in a wide variety of clinical issues. The application is consistently described as safe in studies and meta-analyses, although there are notes that using essential oils can also have side effects, especially dermatologically. However, it can be considered as confirmed that essential oils have positive influences on humans and can improve quality of life in patients with psychiatric disorders, critically ill patients, and patients in other exceptional situations. Although the positive effect of essential oils from blossoms has repeatedly been reported, evidence-based clinical investigations are still underrepresented, and the need for research is demanded.

Lavender Plant: Farming and Health Benefits

Natural remedies from a range of sources, including plants, animals, microorganisms, and marine life, have made a significant contribution to the treatment of many ailments. Lavender is a Mediterranean shrub from the Lamiaceae family. Lavender flowers (Lavandula flores) include active ingredients (3%), anthocyanins, sugars, phytosterols, minerals, and tannins and are majorly used for herbal applications. Lavender essential oil's descriptive and analytical composition varies depending on genotype, growing region, climatic circumstances, propagation, and morphological characteristics. There are around 300 chemical components in essential oil. Linalool, terpinen-4-ol, linalyl acetate, ocimene, acetate lavandulol, and cineole are the most prominent constituents. Lavender oil has antibacterial and antioxidant properties. The lavender extract helps to prevent dementia and may slow cancer cell growth, while lavender oil is used to treat skin problems. This review will cover the recent medical, economic and regional advancements in levander propagation and how the Council of Scientific & Industrial Research Indian Institute of Integrative (CSIR IIIM) aroma mission is actively acting as a bridge between farmers and their economic improvement by attracting them to the field of medicinal plant cultivation.

An Antennae-Enriched Odorant-Binding Protein EonuOBP43 Mediate the Behavioral Response of the Tea Green Leafhopper, Empoasca onukii Matsuda to the Host and Nonhost Volatiles

Olfaction is crucial for Empoasca onukii Matsuda to recognize odors from the host and nonhost plants, and it has been proposed that odorant binding proteins are directly required for odorant discrimination and represent potential targets of interest for pest control. Here, we cloned EonuOBP43 and expressed the recombinant EonuOBP43 protein. Furthermore, competitive fluorescence binding assays with 19 ligands indicated that terpenoids and alkanes showed a relatively higher than for other classes of chemicals. Additionally, ligand docking and site-directed mutagenesis results revealed that seven hydrophobic residues, including Val-86, Met-89, Phe-90, Ile-104, Ile-105, Leu-130, and Val-134, played a key role in the binding of EonuOBP43 to plant volatiles. In olfactometer tests, E. onukii were significantly attracted to α-farnesene and repelled to β-caryophyllene, and dsOBP43 treated adult lost response to α-farnesene and β-caryophyllene. In summary, our results demonstrated that EonuOBP43 may function as a carrier in the process of sensing plant compounds of E. onukii.

Chemical Composition of Essential Oils and Supercritical Carbon Dioxide Extracts from Amomum kravanh, Citrus hystrix and Piper nigrum 'Kampot'

The fruits of Amomum kravanh, Citrus hystrix and Piper nigrum 'Kampot' are traditionally used as spices in Cambodian cuisine. In this study, the chemical composition of essential oils (EOs) and supercritical CO2 extracts from all three species was determined using GC-MS, with two columns of different polarity (HP-5/DB-HeavyWAX). Differences between the chemical profile of the EOs and CO2 extracts were observed for all species. The greatest difference was detected in A. kravanh EO containing mainly eucalyptol (78.8/72.6%), while the CO2 extract was rich in fatty acids (13/55.92%) and long-chain alkanes (25.55/9.54%). Furthermore, the results for the CO2 extract of this species differed, where tricosane (14.74%) and oleic acid (29.26%) were the main compounds identified when utilizing the HP-5 or DB-HeavyWAX columns, respectively. Moreover, the EO and CO2 extract from P. nigrum 'Kampot' fruits and the CO2 extract from C. hystrix fruit peel, containing respective amounts 34.84/39.55% (for EO) and 54.21/55.86% (for CO2 extract) of β-caryophyllene and 30.2/28.9% of β-pinene, were isolated and analyzed for the first time. Generally, these findings suggest that supercritical CO2 could potentially be used for the extraction of all three spices. Nevertheless, further research determining the most efficient extraction parameters is required before its commercial application.

Alginate-Based Hydrogels Enriched with Lavender Essential Oil: Evaluation of Physicochemical Properties, Antimicrobial Activity, and In Vivo Biocompatibility

Owing to its antibacterial, anti-inflammatory, and antioxidant activities, in the last few years, lavender essential oil (LVO) has been used in medical applications as a promising approach for treating infected wounds. However, the practical applicability of LVO is limited by its high volatility and storage stability. This study aimed to develop a novel hybrid hydrogel by combining phytic acid (PA)-crosslinked sodium alginate (SA) and poly(itaconic anhydride-co-3,9-divinyl-2,4,8,10-tetraoxaspiro[5.5] undecane (PITAU) and evaluate its potential effectiveness as an antibacterial wound dressing after incorporating LVO. The influence of the mass ratio between SA and PITAU on the properties and stability of hydrogels was investigated. After LVO loading, the effect of oil addition to hydrogels on their functional properties and associated structural changes was studied. FTIR analysis revealed that hydrogen bonding is the primary interaction mechanism between components in the hybrid hydrogels. The morphology was analyzed using SEM, evidencing a porosity dependent on the ratio between SA and PITAU, while LVO droplets were well dispersed in the polymer blend. The release of LVO from the hydrogels was determined using UV-VIS spectroscopy, indicating a sustained release over time, independent of the LVO concentration. In addition, the hybrid hydrogels were tested for their antioxidant properties and antimicrobial activity against Gram-positive and Gram-negative bacteria. Very good antimicrobial activity was obtained in the case of sample SA_PITAU3+LVO10% against S. aureus and C. albicans. Moreover, in vivo tests showed an increased antioxidant effect of the SA_PITAU3+LVO10% hydrogel compared to the oil-free scaffold that may aid in accelerating the healing process of wounds.

Qualitative and Quantitative Comparison of Aromatic Oil Components and Antifungal Effects of Cymbopogon flexuosus Obtained with Supercritical CO2, Microwave-Ultrasonic, Steam Distillation, and Hydrodistillation Extraction Techniques

Cymbopogon flexuosus is a highly valued botanical species with significant applications in the food and food supplement industries, medicine, and cosmetics. The effects of four extraction techniques, supercritical CO2, microwave-ultrasonic, steam distillation, and hydrodistillation techniques, on the yield, phytochemical constituents, and antifungal activity against nine fungal species of Cymbopogon flexuosus aromatic oil (AO) were explored in this investigation. Gas chromatography connected with a mass spectrometry apparatus was employed for the qualitative and quantitative analyses of the investigated plant AOs. In addition, using the broth microdilution method, minimum inhibitory concentrations (MICs) were calculated for several fungi species. The supercritical CO2 method gave the highest yield of AO (11.62 ± 0.03 (w/w)) followed by the microwave-ultrasonic method (1.55 ± 0.05% (w/w)) and the steam distillation method (1.24 ± 0.04% (w/w)), while the hydrodistillation methods gave the lowest yield (1.17 ± 0.01 (w/w)). In addition, eighteen molecules were specified in the AOs obtained with the supercritical CO2, microwave-ultrasonic, steam distillation, and hydrodistillation techniques, which constituted 99.36, 98.6, 98.21, and 98.31% (v/v) of the total oils, respectively. Additionally, linalyl acetate was the trending molecule in the microwave-ultrasonic and steam distillation methods, representing 24.61 and 24.34% (v/v), respectively, while geranial was the dominant molecule in the AOs extracted with the hydrodistillation and supercritical CO2 extraction techniques (27.01 and 25.6% (v/v), respectively). The antifungal screening results revealed that the tested C. flexuosus AOs have potential antifungal effects against all the screened fungi species. The antifungal effect of the AOs extracted with the steam distillation and microwave-ultrasonic methods was remarkable compared with that of the commercial antifungal drug Fluconazole. However, the AOs extracted with these two methods have a more potent antifungal effect against Candida parapsilosis than that of Fluconazole with MICs of 3.13 ± 0.01, 3.13 ± 0.01, and 6.25 ± 0.91 µg/mL, respectively. The same effects were also observed against Trichophyton rubrum with MICs of 6.25 ± 0.91 µg/mL, respectively. The results of this investigation demonstrated that the steam distillation and microwave-ultrasonic methods are promising processes for the extraction of C. flexuosus AO with a potent antifungal effect. This may be an advantage for the utilization of C. flexuosus AO over some antifungal synthetic agents commonly utilized as medicines, preservatives, food additives, cosmetics, and nutrient supplements.

Emerging Insights into the Applicability of Essential Oils in the Management of Acne Vulgaris

The occurrence of pustules, comedones, nodules, and cysts defines acne vulgaris, a prevalent chronic inflammatory dermatological condition. In the past few decades, essential oils extracted from varied natural sources have acquired recognition due to their potential medicinal applications in acne therapy. However, there is not yet sufficient medical data to fully characterize this interaction. Multiple factors contribute to the development of acne vulgaris, including excessive sebaceous production, inflammatory processes, hyperkeratinization, and infection with Cutibacterium acnes. Essential oils, including oregano, lavender, lemon grass, myrtle, lemon, thyme, eucalyptus, rosemary, and tea tree, have been found to possess anti-inflammatory, antioxidant, and antimicrobial properties, which may target the multifactorial causes of acne. Analytical methods for determining antioxidant potential (i.e., total phenolic content, diphenyl-1-picrylhydrazyl free radical scavenging assay, reducing power assay, ferrous ion chelating activity, thiobarbituric acid reactive species assay, β-carotene bleaching assay, etc.) are essential for the evaluation of these essential oils, and their method optimization is crucial. Further studies could include the development of novel acne treatments incorporating essential oils and an assessment of their efficacy in large clinical trials. In addition, further research is necessary to ascertain the mechanisms of action of essential oils and their optimal doses and safety profiles for optimal implementation in the management of acne vulgaris.

A New Lavender (Lavandula multifida L.) Ecotype from Arid Tunisia, with Differential Essential Oil Composition and Higher Antimicrobial Potential

The lavender Lavandula multifida L., a medicinal plant grown in arid regions of Tunisia, was recently considered an endangered species; thus, its habitats regressed to some difficult zones in terms of access, such as the watershed of Oued Agareb in central-eastern Tunisia. This species was recorded only in deep and narrow shady Wadi of the watershed and benefited from protection against overgrazing, erosion and sunlight. L. multifida was rarely observed in an open area, such as a plateau or large-bed valley. The plant's metabolism is linked to its response to environmental conditions, which is of particular interest to understanding the components of the considered population of L. multifida. Consequently, biochemical and antimicrobial analyses have been evaluated. Using gas chromatography-mass spectrometry (GC-MS) analysis reveals that among the 58 compounds identified in L. multifida essential oil extracted from aboveground plant tissues, camphor was the major component (15.68%), followed by 1,8-cineole (14.14%) and alpha-pinene (13.82%). Moreover, it has been observed that Escherichia coli was more susceptible than Staphylococcus aureus to the antimicrobial properties of L. multifida essential oil, while in the case of camphor, S. aureus was more susceptible than E. coli. The protected population of L. multifida exhibits a distinctive vegetative development and growth cycle, resulting in specific secondary metabolites and distinguished antimicrobial activity.

Binary Synergistic Combinations of Lavender and Fennel Essential Oils with Amoxicillin

Microbial resistance is an important problem in modern healthcare systems. In addition to drug resistance, the side effects of current antibiotic applications are also known issues. In this present study, binary combinations of amoxicillin with European Pharmacopoeia quality lavender (Lavandula angustifolia) and fennel (Foeniculum vulgare) essential oils were evaluated against human pathogenic microbial strains. The checkerboard method was used to quantify the efficacy of the essential oils in combination with amoxicillin. As an initial result, remarkable in vitro antimicrobial activity was observed at relatively low amoxicillin concentrations using different oil combinations against Staphylococcus aureus ATCC 6538, Enterococcus faecalis ATCC 29212, Bacillus cereus ATCC 14579, Escherichia coli NRRL B-3008, Salmonella typhi (clinical isolate), respectively. Fractional inhibitory concentrations were calculated and interpreted in terms of addition, synergy, antagonism, or indifferent. A synergistic interaction with the combination F. vulgare essential oil and amoxicillin (fractional inhibitory concentration index = 8.05 × 10^-4) was observed against the pathogens E. faecalis and Escherichia coli. Both essential oils together and in combination with amoxicillin showed a synergistic effect with possible future applications.

Effect of Different Extraction Methods on Quality Characteristics of Rapeseed and Flaxseed Oils

This study reports the effect of roasted pretreatment combined with screw press, hydraulic press, and Soxhlet extraction methods on various quality indexes of rapeseed and flaxseed oils, including the oil yield, sensory indexes (color, smell, clarity, viscosity, and colligation score), physicochemical properties (acid value, peroxide value, saponification value, moisture and volatiles), major components (fatty acid composition and triglyceride composition), and minor components (volatile compounds, total phenols, and vitamin E contents). The results indicated that the oil yield, sensory indexes, physicochemical properties, fatty acid composition, volatile compounds, total phenol, and vitamin E contents in vegetable oils have been significantly affected by different extraction methods. The yields of rapeseed and flaxseed oils of Soxhlet extraction method were increased by 30.10%–73.90% and 6.30%–54.40%, respectively, compared with other treatment groups. In addition, roasted pretreatment significantly increased the yields of oils by 4.10%–25.00% and 6.70%–23.15%, respectively, compared with the untreated group. The contents of linolenic acid and vitamin E in rapeseed and flaxseed oils extracted from screw press method were higher. In particular, the linolenic acid content of cold-pressed rapeseed oil extracted by screw press increased by 1.50%–23.80% compared with other treatment groups. In addition, the contents of vitamin E in cold-pressed rapeseed oil and flaxseed oil obtained by screw press increased by 1.22%–78.91% and 3.00%–18.80%, respectively. The Soxhlet extraction could improve oil yield and total phenol content, but the quality of the oil was inferior due to high acid values (0.93–3.36 mg KOH/g) and peroxide values (0.70–5.23 meq O2/kg). Furthermore, the hydraulic press method could extract vegetable oils with excellent sensory scores. The roasted pretreatment gives the rapeseed and flaxseed oils a good smell. The major volatile compounds in rapeseed and flaxseed oils were aldehydes, acids, alcohols, heterocycles, and ketones. Different extraction methods and pretreatment had no significant effect on the compositions and contents of triglycerides. This study provides a basic understanding on the selection of appropriate oil extraction techniques for oil extraction at a large scale.

Antibiofilm and Antiquorum Sensing Potential of Lactiplantibacillus plantarum Z057 against Vibrio parahaemolyticus

Vibrio parahaemolyticus is a widespread foodborne pathogen that causes serious seafood-borne gastrointestinal infections. Biofilm and quorum sensing (QS) are critical in regulating these infections. In this study, first, the ability of Lactiplantibacillus plantarum Z057 to compete, exclude, and displace V. parahaemolyticus biofilm was evaluated. Then, the inhibitory effects of L. plantarum Z057 extract (Z057-E) on V. parahaemolyticus biofilm and QS were explored from the aspects of biofilm biomass, metabolic activity, physicochemical properties, extracellular polymer matrix content, QS signal AI-2 activity, biofilm microstructure, and the expression levels of biofilm and QS-related genes. Results showed that L. plantarum Z057 effectively inhibited biofilm formation of V. parahaemolyticus and interfered with the adhesion of V. parahaemolyticus on the carrier surface. In addition, the Z057-E could significantly reduce the biofilm biomass, metabolic activity, hydrophobicity, auto-aggregation ability, swimming and swarming migration diameter, AI-2 activity, extracellular polysaccharide (EPS), and extracellular protein content of V. parahaemolyticus. Fluorescence microscope and scanning electron microscope (SEM) images demonstrated that the Z057-E could efficiently inactivate the living cells, destroy the dense and complete biofilm architectures, and reduce the essential component of the extracellular polymer matrix. Real-time fluorescence quantitative PCR revealed that the Z057-E treatment down-regulated the expression of flagellum synthesis-related genes (flaA, flgM), EPS, and extracellular protein synthesis-related genes (cpsA, cpsQ, cpsR, ompW), QS-related genes (luxS, aphA, opaR), and hemolysin secretion-related genes (toxS, toxR) of V. parahaemolyticus. Thus, our results suggested that L. plantarum Z057 could represent an alternative biocontrol strategy against foodborne pathogens with anti-adhesive, antibiofilm, and antiquorum sensing activities.

Essential Oil Content and Compositional Variability of Lavandula Species Cultivated in the Mid Hill Conditions of the Western Himalaya

The increase in the utilization of Lavandula essential oil in industries led to an impressive rise in the demand for quality essential oils. However, a post-harvest drying of Lavandula species can be a decisive factor to determine the quantity and quality of essential oil. The study was conducted in western Himalayan conditions to assess the essential oil content and composition of two Lavandula species viz., lavender (Lavandula angustifolia Mill.), and lavandin (Lavandula × intermedia Emeric ex Loisel), at four different drying duration (0 h, 24 h, 48 h and 72 h after the harvest). The higher growth attributes viz., plant height (71.7 cm), ear length (8.8 cm), number of spikes (18.1), and number of flowers per ear (47.5) were higher in lavandin, while the number of branches (17.1) was higher in lavender. Essential oil content (%) and moisture reduction (%) were significantly higher at 72 h than at 0 h. The major components of lavender and lavandin essential oil were linalool (33.6–40.5%), linalyl acetate (10.8–13.6%), lavandulyl acetate (2.8–14.5%), and linalyl propionate (5.3–14.1%) in both the Lavandula species. There was a decreasing trend in linalool and an increasing trend in linalyl acetate content in lavandin, with an increase in drying duration up to 72 h; while in lavender, no regular trend was observed in linalool and linalyl acetate content. It was observed that linalool and linalyl acetate levels were the highest at 24 and 0 h of drying in lavender and lavandin, respectively, and essential oil extraction can be done according to the desire of the constituent at varied drying duration.

Polydimethylsiloxane/graphene oxide/β-cyclodextrin sponge as a solid-phase extraction sorbent coupled with GC-MS for rapid adsorption and sensitive determination of lavender essential oil

An adsorbent polydimethylsiloxane/graphene oxide/β-cyclodextrin sponge, which possessed the merits of high surface area, chemical stability, environment friendly and excellent extraction capacity, was successfully fabricated. Based on the advantages, a novel microwave-assisted headspace solid-phase extraction method for lavender essential oil using polydimethylsiloxane/graphene oxide/β-cyclodextrin sponge as adsorbents was developed in this study. Various experimental parameters were studied. The optimal extraction conditions were as follows: 1 mg mL^-1 as dopamine solution concentration, graphene oxide dosages of 30 mg, microwave power of 700 W, microwave irradiation time of 10 min and desorption solvent of n-hexane. Under the optimal extraction condition, linearities ranging from 10 to 800 ng were achieved for six representative compounds with the correlation coefficients value of >0.99. The intra-day and inter-day precisions were in the ranges of 0.40-1.56% and 0.67-2.56%, respectively. Finally, the proposed technique was applied to analyze essential oil constituents in 14 samples of three lavender varieties, and 48 compounds were identified. Lavender varieties were distinguished using principal component analysis and partial least squares discriminant analysis. The results showed that the mothed developed in this study is a novel, simple, and sensitive method for the determination of essential oil in complex plant samples. This article is protected by copyright. All rights reserved.

The elimination effects of lavender essential oil on Listeria monocytogenes biofilms developed at different temperatures and the induction of VBNC state

Listeria monocytogenes is a typical foodborne pathogen that causes hard-to-treat bacterial infections, mainly due to its ability to form biofilm and enter into a viable but non-culturable state (VBNC). In this study, we investigated the removal effects of four antimicrobial agents on L. monocytogenes biofilms formed at 32 ℃ and 10 ℃, analyzed the resistances of the mature biofilms to antimicrobial agents, and explored the VBNC state of cells in mature biofilms induced by lavender essential oil (LEO). The results showed that the growth of L. monocytogenes was completely inhibited when 1.6% (v/v) of the LEO was added. Meanwhile, the results of the crystal violet staining and XTT reduction method indicated that different concentrations of LEO significantly reduced L. monocytogenes biofilms biomass and metabolic activities, followed by sodium hypochlorite, lactic acid, and hydrogen peroxide. Moreover, the confocal laser scanning microscopy (CLSM) images confirmed that the treated biofilms became thinner, the structure was sparse, and the appearance was blurry. More interestingly, L. monocytogenes biofilms developed at 10 ℃ were less susceptible to the sanitizers than that formed at 32 ℃. In addition, LEO presented a more significant dispersing effect on the biofilm cells, and 1/2 MIC to 4 MIC of LEO could induce fewer VBNC state cells in biofilm and plankton compared with sodium hypochlorite. This study indicated that the LEO could be considered as an ideal antibiofilm agent for controlling L. monocytogenes. But we should pay attention to the resistance of the biofilms developed at low temperatures.

Methods used for extraction of plant volatiles have potential to preserve truffle aroma: A review

Truffles are considered one of the world's most highly prized foods mainly due to their desirable organoleptic properties and rarity. However, truffles are seasonal (harvested mostly in winter from June to August in the Southern Hemisphere and from December to February in the Northern Hemisphere) and extremely perishable. Truffles deteriorate rapidly showing undesirable changes within 10 days from harvest in aroma and visual appearance after harvest. The very short postharvest shelf life (about 7-10 days) limits the potential for export and domestic consumption all year round. Several preservation methods have been studied to prolong their shelf life without the loss of aroma. However, all traditional preservation techniques have their own shortcomings and remain challenging. The extraction of natural truffle aroma volatiles for food applications could be a potential alternative to replace the existing synthetic flavoring used for processed truffle products. Four commonly used extraction methods for recovering volatile compounds from plants, namely, supercritical carbon dioxide extraction, Soxhlet extraction, distillation, and cold pressing, are critically analyzed. Up to date, existing research about the extraction of aroma volatiles from truffles is limited in the literature but based on the volatility of the key truffle volatile compounds, supercritical carbon dioxide extraction may offer the best possibility so that a natural truffle-based product that can be used in food applications throughout the year can be made available.

Chemical Profile, In Vitro Biological Activity and Comparison of Essential Oils from Fresh and Dried Flowers of Lavandula angustifolia L

The chemical composition of essential oils (EOs) from dried and fresh flowers of Lavandula angustifolia L. (lavender), named LA 2019 and LA 2020, respectively, grown in central Italy was analyzed and compared by GC and GC-MS. For both samples, 61 compounds were identified, corresponding to 97.9% and 98.1% of the total essential oils. Explorative data analysis, performed to compare the statistical composition of the samples, resulted in a high level of global similarity (around 93%). The compositions of both samples were characterized by 10 major compounds, with a predominance of Linalool (35.3-36.0%), Borneol (15.6-19.4%) and 1,8-Cineole (11.0-9.0%). The in vitro antibacterial activity assay by disk diffusion tests against Bacillus subtilis PY79 and Escherichia coli DH5α showed inhibition of growth in both indicator strains. In addition, plate counts revealed a bactericidal effect on E. coli, which was particularly noticeable when using oil from the fresh lavender flowers at the highest concentrations. An in vitro antifungal assay showed that the EOs inhibited the growth of Sclerotium rolfsii, a phytopathogenic fungus that causes post-harvest diseases in many fruits and vegetables. The antioxidant activity was also assessed using the ABTS free radical scavenging assay, which showed a different antioxidant activity in both EOs. In addition, the potential application of EOs as a green method to control biodeterioration phenomena on an artistic wood painting (XIX century) was evaluated.

Topical Emulsion Containing Lavandula stoechas Essential Oil as a Therapeutic Agent for Cutaneous Wound Healing

Background and objectives: The present research was designed to evaluate the chemical composition of Lavandula stoechas essential oil (EOLS) as well as the in vivo wound-healing property. The chemical composition of EOLS was identified by gas chromatography mass spectrometry. Nineteen compounds of EOLS were reported. Linalool was identified as the major chemical compound (24.87%), followed by linalyl acetate (19.10%). EOLS showed a high content of oxygenated compounds (63.54%). In vivo wound healing activity of the topical cream prepared from EOLS (0.5% w/w) was assessed using a circular excision wound model. The wound area (mm2) in all animal groups was estimated and measured on day 0, 4, 8, 11, and 16. Results: The EOLS formulation cream (0.5% v/w) showed the highest effect on wound models when compared to reference Madecassol® (Asiaticoside). On days 4, 11, and 16, wound contractions were 26.4%, 78%, and 96.3% for the EOLS-treated group, and 8.5%, 64.1%, and 86.1% for the vehicle cream-treated group. Animals treated with EOLS cream showed a significant decrease in the epithelization period, wound area, and scar thickness, whereas the rate of wound contraction significantly increased. This is the first such report to be published. Histological analyses were also consistent with the results of the excision experimental method. Treatment with EOLS cream formulation resulted in decreased inflammation and an increased rate of tissue perfusion and proliferation as well as remodeling, along with re-epithelization. Conclusions: Our results support the use of EOLS in the development of pharmaceuticals for the management of wounds, and/or inflammatory-related diseases. Additional studies are needed to elucidate and explain the exact mechanism of its pharmacological activity.

Integrated Analysis of Transcriptome and Metabolome and Evaluation of Antioxidant Activities in Lavandulapubescens

Lavandula pubescens, belonging to the Labiatae family, is a newly discovered strongly aromatic species of lavender that is potentially beneficial for human health. Given the economic importance of lavender species, we sought in this study to characterize the terpenoid biosynthesis of L. pubescens by obtaining transcriptomic and metabolic datasets. Transcriptome analysis of L. pubescens grown aseptically in tissue culture medium yielded 124,233 unigenes with an average length of 470 bp and N50 value of 522 bp from 9,476,122,928 raw reads. In order to provide relevant biological information, the unigenes were annotated using the following public databases: National Center for Biotechnology Information (NCBI) nucleotide (NT) and non-redundant protein (NR), Brassica (BRAD), Arabidopsis Information Resource (TAIR), Clusters of Orthologous Groups (COG), and Gene Ontology (GO). NR annotation results revealed that L. pubescens is genetically closely related to Sesamum indicum. On the basis of the transcriptome data, a total of 14 cDNA clones encoding the terpene biosynthetic genes LpDXS, LpMCT, LpMCS, LpHDR, LpIDI, LpAACT, LpHMGS, LpHMGR, LpMVK, LpPMK, LpMVD, LpGPPS, LpSQS, and LpGGPPS were identified in L. pubescens. These were quantified in the roots, stems, and leaves of L. pubescens using quantitative real-time polymerase chain reaction (qRT-PCR), which revealed that the gene expression levels were higher in the leaves and stems than in the roots, which was found to be consistent with the levels of ursolic and oleanolic acids in the different organs using high-performance liquid chromatography (HPLC). A total of 48 hydrophilic metabolites were identified and quantified in the organs using gas chromatography time-of-flight mass spectrometry (GC-TOFMS). Furthermore, the antioxidant activity of an ethyl acetate extract of L. pubescens leaves was examined using different methods to determine the potential therapeutic properties. A reducing power assay revealed that the absorbance values increased in a concentration-dependent manner, whereas a 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay indicated the strong activity (60.4 ± 0.9%) of the ethyl acetate extract at a concentration of 100 µg/mL, which also showed strong hydrogen peroxide (57.4 ± 2.7%), superoxide radical (62.1 ± 0.7%), and hydroxyl radical (58.6 ± 0.4%) scavenging activities.

Thermolabile essential oils, aromas and flavours: Degradation pathways, effect of thermal processing and alteration of sensory quality

Plant-based aroma chemicals, constituting the essential oils play a great role as the natural flavours and preservatives in the food industries. Many of these metabolites are susceptible to degradation under heat (i.e. thermolabile aroma chemicals) which may influence the organoleptic properties of the end-products e.g. essential oil, oleoresin, dry herb, tea and packaged juice. The current review identified in total 42 thermolabile aroma and/or flavour molecules belonging to monoterpenoids, sesquiterpenoids and phenolics. The probable pathway of their degradation and its promoting conditions were also described. Degradation pathways were categorized into five major classes including oxidation, C-C bond cleavage, elimination, hydrolysis and rearrangement. Numerous evidences were cited in support of the thermosensitivity of these phytochemicals under pyrolytic, thermal heating or gas chromatographic conditions. Various post-harvest processes involved in the manufacturing such as drying and distillation of the crops or thermal treatment of the food-products for storage were highlighted as the root cause of degradation. The influence of thermolabile aroma chemicals to maintain the sensory quality of the end-products such as citrus juices, floral oils and thermally cooked foods was discussed in detail. In the present article, detailed insight into the chemical and sensory aspects of thermosensitive aromas and flavours was provided, covering the period from 1990 up to 2020.

Combination Therapy Involving Lavandula angustifolia and Its Derivatives in Exhibiting Antimicrobial Properties and Combatting Antimicrobial Resistance: Current Challenges and Future Prospects

Antimicrobial resistance (AMR) has been identified as one of the biggest health threats in the world. Current therapeutic options for common infections are markedly limited due to the emergence of multidrug resistant pathogens in the community and the hospitals. The role of different essential oils (EOs) and their derivatives in exhibiting antimicrobial properties has been widely elucidated with their respective mechanisms of action. Recently, there has been a heightened emphasis on lavender essential oil (LEO)’s antimicrobial properties and wound healing effects. However, to date, there has been no review published examining the antimicrobial benefits of lavender essential oil, specifically. Previous literature has shown that LEO and its constituents act synergistically with different antimicrobial agents to potentiate the antimicrobial activity. For the past decade, encapsulation of EOs with nanoparticles has been widely practiced due to increased antimicrobial effects and greater bioavailability as compared to non-encapsulated oils. Therefore, this review intends to provide an insight into the different aspects of antimicrobial activity exhibited by LEO and its constituents, discuss the synergistic effects displayed by combinatory therapy involving LEO, as well as to explore the significance of nano-encapsulation in boosting the antimicrobial effects of LEO; it is aimed that from the integration of these knowledge areas, combating AMR will be more than just a possibility.

Comparison of Chemical Composition and Biological Properties of Essential Oils Obtained by Hydrodistillation and Steam Distillation of Laurus nobilis L

The purpose of this study was to compare the yield, chemical composition, antimicrobial and antioxidant properties of essential oils isolated from leaves of Laurus nobilis L. by two different distillation methods. The essential oils isolated by hydrodistillation (HD) and steam distillation (SD) were analyzed by gas chromatography coupled to mass spectrometry (GC-MS) and gas chromatography with flame ionization detector (GC-FID). Hydrodistillation produced a yield of 0.95 ± 0.06% which is slightly higher than yield obtained by steam distillation 0.79 ± 0.07%. Seventy three compounds in the bay leaves oil obtained by steam distillation were identified while in essential oil obtained by hydrodistillation were identified only 54 compounds. The antioxidant activity was evaluated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical method. Antimicrobial activity of obtained essential oils was evaluated by disc diffusion method in comparison with several chosen antimicrobials. The antimicrobial activity was tested on five microorganisms - Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa and Candida albicans. In general, oils produced by steam distillation had higher antimicrobial and antioxidant activities than hydrodistillation extracts. It seems that hydrodistillation is better for higher yield while steam distillation is better to use for more quality oils with stronger biological properties.

Fostering Lavender as a Source for Valuable Bioactives for Food and Pharmaceutical Applications through Extraction and Microencapsulation

Lavender flowers were used in this study as a source of phytochemicals as naturally occurring antioxidants. Two different extraction techniques were applied, such as ultrasound-assisted (UAE) and supercritical fluids (SCE) methods. The comparative evaluation of the phytochemicals profile evidenced a higher content of chlorophyll a and b of 5.22 ± 0.12 mg/g dry weight (D.W.) and 2.95 ± 0.16 mg/g D.W, whereas the carotenoids content was 18.24 ± 0.04 mg/g D.W. in the SCE extract. Seven main compounds were found in both extracts: β-linalool, eucalyptol, linalool acetate, β-trans-ocimene, and limonene in SCE and linalool acetate, β-linalool, 6-methyl-2-(2-oxiranyl)-5-hepten-2-ol, linalool oxide, lavandulyl acetate and camphor in UAE. The (n-3) acids had a higher contribution in SCE. The extracts were microencapsulated in different combinations of wall materials based on polysaccharides and milk proteins. The four variants showed different phytochemical and morphological profiles, with a better encapsulating efficiency for proteins (up to 98%), but with a higher content of encapsulated carotenoids for polysaccharides, the latter showing remarkable antimicrobial activity against selected microorganisms. Carboxymethyl cellulose and whey proteins led to a double encapsulation of lipophilic compounds. The powders were tested in two food matrices as ingredients, with multiple targeted functions, such as flavoring, antimicrobial, antioxidant activity that can successfully replace synthetic additives.

Chemical Composition of Two Different Lavender Essential Oils and Their Effect on Facial Skin Microbiota

Lavender oil is one of the most valuable aromatherapy oils, its anti-bacterial and anti-fungal activities can be explained by main components such as linalool, linalyl acetate, lavandulol, geraniol, or eucalyptol. The aim of the study was to assess the anti-microbial effects of two different lavender oils on a mixed microbiota from facial skin. The commercial lavender oil and essential lavender oil from the Crimean Peninsula, whose chemical composition and activity are yet to be published, were used. Both oils were analysed by gas chromatography coupled to mass spectrometry. The composition and properties of studied oils were significantly different. The commercial ETJA lavender oil contained 10% more linalool and linalyl acetate than the Crimean lavender oil. Both oils also had different effects on the mixed facial skin microbiota. The Gram-positive bacilli were more sensitive to ETJA lavender oil, and Gram-negative bacilli were more sensitive to Crimean lavender oil. However, neither of the tested oils inhibited the growth of Gram-positive cocci. The tested lavender oils decreased the cell number of the mixed microbiota from facial skin, but ETJA oil showed higher efficiency, probably because it contains higher concentrations of monoterpenoids and monoterpenes than Crimean lavender oil does.

Phytotoxic Effects of Commercial Eucalyptus citriodora, Lavandula angustifolia, and Pinus sylvestris Essential Oils on Weeds, Crops, and Invasive Species

Background: essential oils are well known for their pharmacological effectiveness as well as their repellent, insecticide, and herbicide activities. The emergence of resistant weeds, due to the overuse of synthetic herbicides, makes it necessary to find natural alternatives for weed control. The aim of this study was to evaluate the phytotoxic effects of Eucalyptus citriodora, Lavandulaangustifolia, and Pinus sylvestris, three common commercial essential oils, on weeds (Portulaca oleracea, Lolium multiflorum, and Echinochloa crus-galli), food crops (tomato and cucumber), and the invasive species Nicotiana glauca. Methods: to determine herbicidal effects, essential oils were tested at different concentrations (0.125–1 µL/mL). The index of germination and seedling length data were recorded over 14 days. Results: the in vitro assays showed that L. angustifolia with linalool (38.7 ± 0.1%), 1,8-cineole (26.5 ± 0.1%), and camphor (14.2 ± 0.1%) as the main compounds showed the most phytotoxic effects affecting seed germination in weeds and tomato, and the aforementioned invasive species. L. multiflorum was the most sensitive weed, particularly to lavender essential oil, which decreased the growth of its hypocotyl and radicle by 87.8% and 76.7%, respectively, at a dose of 1 µL/mL. Cucumber was the most resistant food crop, with no significant reduction observed in seed germination and hypocotyl growth with E. citriodora and L. angustifolia essential oils. Conclusions: lavender essential oil represents a promising candidate for the development of effective and safe herbicides in the management of L. multiflorum affecting cucumber crops.

Effect of pressure variation on the efficiency of supercritical fluid extraction of wild carrot (Daucus carota subsp. maritimus) extracts

The present study was conducted to check the comparative qualities of essential oils prepared by hydrodistillation (HD) and supercritical fluid techniques. It constitutes the first attempt to investigate the chemical composition of Daucus carota subsp. maritimus extracts using supercritical fluid technology (SFE) as an environmentally clean innovative method of extraction. The effect of pressure on the nature of extractable substances from wild carrot has been performed at a constant temperature of 50 °C and two different pressures (100 and 300 bar). The experimental results showed that pressure had a significant enhancing effect on the fluid transport properties and therefore on yield values. The extraction yield increases from 1.167 to 2.986% while increasing pressure. The chemical compositions of the essential oils prepared by HD and SFE were analyzed on the basis of gas chromatography-mass spectroscopy (GC-MS). Thus, we noticed that all analyzed samples were enriched in geranyl acetate and β‑bisabolene, and that the quantities of different identified substances were extremely sensitive to the extraction method and to the pressure variation in case of SFE.

Influence of Monoterpenes in Biological Activities of Nectandra megapotamica (Spreng.) Mez Essential Oils

Investigating the influence of seasonal variations on biological activities is important for pharmacological studies and metabolic engineering. Therefore, this study was conducted to determine the variation of the chemical composition of essential oils obtained from Nectandra megapotamica leaves, collected at different stages of plant development, as well as its influence on the biological activities. A total of 38 compounds were identified that accounted for 97–99.2% of the chemical composition of the oils. Major differences were observed in the monoterpenic fraction, representing 5.1% of the compounds identified in the productive rest phase to 37.1% in the blooming phase. Bicyclogermacrene and germacrene D were the predominant compounds identified in the oil of all collections. Furthermore, limonene, β-pinene, and spathulenol were identified predominantly in the samples of blooming and fruiting phases. The oils exhibited significant antichemotactic activity and different effects in scavenging the radical 2,2-diphenyl-1-picrylhydrazyl. Variations were also observed in the antifungal activity, with the minimum inhibitory concentrations ranging from 125 to 500 μg/mL. These results demonstrate the influence of monoterpenes, primarily limonene, α-pinene, and β-pinene, on the bioactivities of the oil. Studies investigating the variations in the chemical composition of essential oil may offer a strategy to produce a compound or a group of compounds of interest to industries with a specific pharmacological focus.

Chemical Composition and Antimicrobial Activities of Artemisia argyi Lévl. et Vant Essential Oils Extracted by Simultaneous Distillation-Extraction, Subcritical Extraction and Hydrodistillation

Artemisia argyi Lévl. et Vant essential oil could be used as a good antimicrobial flavouring agent and applied in the food industry. In this study, three methods, including simultaneous distillation-extraction (SDE), subcritical extraction and hydrodistillation, were applied to extract A. argyi essential oil. Compared with subcritical extraction (1%) and hydrodistillation (0.5%), SDE gave a higher yield (1.2%). Components of the essential oils were analysed with gas chromatography-mass spectrometry (GC-MS), and the most abundant ingredients were caryophyllene oxide, neointermedeol, borneol, α-thujone and β-caryophyllene. These five components accounted for 82.93%, 40.90% and 40.33% for SDE, subcritical extraction, and hydrodistillation, respectively. Based on agar disc diffusion and minimum inhibitory concentration (MIC) assays, SDE oil showed a significant inhibitory effect towards Listeria monocytogenes, Escherichia coli, Proteus vulgaris, Salmonella enteritidis and Aspergillus niger. Furthermore, electron microscope observations (SEM) confirmed that SDE oil could obviously deform cell morphology and destroy the structure of cell walls. Performances showed that SDE was a promising process for extracting A. argyi essential oil with both high yield and antimicrobial activity.

Optimization of Microwave-assisted Extraction of Essential Oil from Lavender Using Response Surface Methodology

A microwave-assisted hydrodistillation (MAHD) method was investigated for extraction of essential oils from lavender. The essential oil extracts at optimized MAHD conditions was compared with hydrodistillation (HD). Response surface methodology coupled with Box-Behnken design was applied to optimize the parameters for MAHD. The optimized MAHD conditions were 500 W microwave power, 17 mL/g liquid-to-solid ratio and 40 min microwave time. The ANOVA results revealed that microwave time had the greatest impact on the essential oil yield followed by liquid-to-solid ratio and microwave power. Under the MAHD optimized conditions, the essential oil yield was 3.19%, approximating the predicted yield (3.20%). MAHD was superior in terms of saving energy and extraction time (40 min, compared to 120 min in HD). The essential oil analyzed by GC-MS, presented 39 compounds constituting 98.37% and 97.51% of the essential oils obtained through MAHD and HD, respectively. No obvious differences were found in composition between MAHD oil and HD oil. Antimicrobial study showed that the lavender essential oil exhibited broad-spectrum antibacterial activity and the MAHD oil showed a higher antimicrobial activity than the HD oil. This study revealed that MAHD could be a good method for extracting essential oil in lavender and other aromatic plants.

Antimicrobial Activity of New Materials Based on Lavender and Basil Essential Oils and Hydroxyapatite

This study presents, for the first-time, the results of a study on the hydrodynamic diameter of essential oils (EOs) of basil and lavender in water, and solutions of EOs of basil (B) and lavender (L) and hydroxyapatite (HAp). The possible influence of basil and lavender EOs on the size of hydroxyapatite nanoparticles was analyzed by Scanning Electron Microscopy (SEM). We also investigated the in vitro antimicrobial activity of plant EOs and plant EOs hydroxyapatite respectively, against Gram-positive bacteria (methicillin-resistant Staphylococcus aureus1144 (MRSA 1144) and S. aureus 1426) and Gram-negative bacteria (Escherichia coli ATCC 25922 and Escherichia coli ESBL 4493). From the autocorrelation function, obtained by Dynamic Light Scattering (DLS) measurements it was observed that basil yielded one peak at an average hydrodynamic diameter of 354.16 nm, while lavender yielded one peak at an average hydrodynamic diameter of 259.76 nm. In the case of HAp nanoparticles coated with basil (HApB) and lavender (HApL) essential oil, the aggregation was minimal. We found that the lavender EO exhibited a very good inhibitory growth activity (MIC values ranging from <0.1% for E. coli reference strain to 0.78% for S. aureus strains). The biological studies indicated that HapL material displayed an enhanced antimicrobial activity, indicating the potential use of HAp as vehicle for low concentrations of lavender EO with antibacterial properties. Flow cytometry analysis (FCM) allowed us to determine some of the potential mechanisms of the antimicrobial activities of EOs, suggesting that lavender EO was active against E. coli by interfering with membrane potential, the membrane depolarization effect being increased by incorporation of the EOs into the microporous structure of HAp. These findings could contribute to the development of new antimicrobial agents that are urgently needed for combating the antibiotic resistance phenomena.

The complete chloroplast genome sequence of the fragrant plant Lavandula angustifolia (Lamiaceae)

Chloroplast (cp) genome sequences have become a useful popular tool for population and phylogeny recently. It is little known about genetics information of Lavandula angustifolia. Here, the complete chloroplast genome of the L. angustifolia has been reconstructed from the whole-genome Illumina sequencing data. The circular genome is 153,448 bp in size, and comprises of a pair of inverted repeat (IR) regions of 25,632 bp each, a large single-copy (LSC) region of 84,588 bp and a small single-copy (SSC) region of 17,596 bp. The total GC content is 38.0%, while the corresponding values of the LSC, SSC, and IR regions are 36.2, 31.8, and 43.2%, respectively. The chloroplast genome contains 132 genes, including 88 protein-coding genes, 8 ribosomal RNA genes, and 37 transfer RNA genes. The Maximum-Likelihood phylogenetic analysis showed a strong sister relationship with Salvia miltiorrhiza in Lamiaceae. These findings provide a foundation for further investigation of cp genome evolution in L. angustifolia and other higher plants.

Phytochemical profiling of anti-inflammatory Lavandula extracts via RP-HPLC-DAD-QTOF-MS and -MS/MS: Assessment of their qualitative and quantitative differences

As for other aromatic plants, there are many analytical methods for the determination of volatile compounds in lavender essential oils. Alternatively, in this study RP-HPLC-DAD-QTOF-MS was used for the profiling of the phytochemical constituents of hydromethanolic extracts of L. stoechas and L. dentata, which were obtained by pressurized liquid extraction. The spectrometric data revealed complex profiles constituted of a wide range of polar and semi-polar phytochemicals, mainly, phenolic compounds (68). Most phenolic compounds (55) have not been previously reported in Lavandula; such is the case of caffeic acid-based oligomers. Moreover, the analytical method was validated for the determination of phenolic compounds. Our findings showed both qualitative and quantitative differences between the extracts. In this sense, while hydroxycinnamic acids made up the largest class in both extracts, flavones were the most abundant class, accounting for 10.44 g (L. dentata) and 4.85 g (L. stoechas) per 100 g of dry extract. In conclusion, this analytical method provided essential information about the phytochemical composition of the studied medicinal plants, revealing novel constituents that were probably hidden for others. In addition, these results may help to understand the anti-inflammatory properties of these extracts.

Plant Essential Oils Synergize and Antagonize Toxicity of Different Conventional Insecticides against Myzus persicae (Hemiptera: Aphididae)

Plant-derived products can play an important role in pest management programs. Essential oils from Lavandula angustifolia (lavender) and Thymus vulgaris (thyme) and their main constituents, linalool and thymol, respectively, were evaluated for insecticidal activity and synergistic action in combination with insecticides against green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae). The essential oils and their main constituents exerted similar insecticidal activity when aphids were exposed by direct sprays, but were non-toxic by exposure to treated leaf discs. In synergism experiments, the toxicity of imidacloprid was synergized 16- to 20-fold by L. angustifolia and T. vulgaris essential oils, but far less synergism occurred with linalool and thymol, indicating that secondary constituents of the oils were probably responsible for the observed synergism. In contrast to results with imidacloprid, the insecticidal activity of spirotetramat was antagonized by L. angustifolia and T. vulgaris essential oils, and linalool and thymol. Our results demonstrate the potential of plant essential oils as synergists of insecticides, but show that antagonistic action against certain insecticides may occur.

Antioxidant and antimycotic activities of two native lavandula species from portugal

The antioxidant and antimycotic activities of the essential oils and extracts of two native Portuguese Lavandula species, L. stoechas subsp. luisieri and L. pedunculata, were evaluated by in vitro assays. The total phenolics and flavonoids content were also determined. The antioxidant potential was assessed through DPPH radical scavenging, inhibition of lipid peroxidation (ILP), and DNA protection assays. All samples displayed a high DPPH scavenging activity, some of them showing concentration dependence. The majority of the samples were also able to inhibit lipid peroxidation. A strong correlation was observed between the results of DPPH and ILP assays and the flavonoids content of the samples. In the DNA protection assay, all the extracts were able to preserve DNA integrity. The antimycotic activity was performed against twelve fungi belonging to Basidiomycota and Ascomycota Divisions. L. stoechas subsp. luisieri exhibited the broadest activity spectra. L. pedunculata extracts were active against five fungi. Cryptococcus neoformans was the most sensitive, being inhibited by all the extracts. Our results led to the conclusion that L. stoechas subsp. luisieri and L. pedunculata can be useful as new sources of natural antioxidants and antimycotic agents, providing a possible valorization of the existing biodiversity and resources of Portuguese flora.

Essential oils and distilled straws of lavender and lavandin: a review of current use and potential application in white biotechnology

The Lavandula genus, which includes lavender (Lavandula angustifolia) and lavandin (L. angustifolia × Lavandula latifolia), is cultivated worldwide for its essential oils, which find applications in perfumes, cosmetics, food processing and, more recently, in aromatherapy products. The chemical composition of lavender and lavandin essential oils, usually produced by steam distillation from the flowering stems, is characterized by the presence of terpenes (e.g. linalool and linalyl acetate) and terpenoids (e.g. 1,8-cineole), which are mainly responsible for their characteristic flavour and their biological and therapeutic properties. Lavender and lavandin distilled straws, the by-products of oil extraction, were traditionally used for soil replenishment or converted to a fuel source. They are mineral- and carbon-rich plant residues and, therefore, a cheap, readily available source of valuable substances of industrial interest, especially aroma and antioxidants (e.g. terpenoids, lactones and phenolic compounds including coumarin, herniarin, α-bisabolol, rosmarinic and chlorogenic acids). Accordingly, recent studies have emphasized the possible uses of lavender and lavandin straws in fermentative or enzymatic processes involving various microorganisms, especially filamentous fungi, for the production of antimicrobials, antioxidants and other bioproducts with pharmaceutical and cosmetic activities, opening up new challenging perspectives in white biotechnology applications.