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

A facile synthesis of silver nanowires and their evaluation in the mitochondrial membrane potential

Silver nanowires (AgNWs) with a high-aspect-ratio were successfully synthesized by a green method using Lavandula angustifolia plant extract. The morphology of the AgNWs was evaluated as a function of the concentration of precursor salt and nucleating agent. Furthermore, AgNWs were analyzed in a biological model using rat liver mitochondria by measuring their effect on membrane potential. The scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM) techniques structurally characterized the nanowires obtained. Also, ultraviolet-visible spectroscopy (UV-Vis) investigated the optical properties of AgNWs. Structural studies show AgNWs fcc with lengths up to 100 μm and diameters ranging from 60 to 130 nm growing in the [110] orientation. Both the CuSO₄ nucleating agent and the centrifugation process are essential for the growth of nanowires. Furthermore, inhibition of mitochondrial membrane potential (MMP) depends on the concentration of the nanowires (NWs), suggesting dissipation of the electron transport chain. In this way, AgNWs can be used as a potential tool to verify biological reactions, such as modulation of metabolic pathways, together with the evaluation of a possible influence of biotic or abiotic factors in organisms.

The best route of administration of lavender for anxiety: a systematic review and network meta-analysis

BACKGROUND

There is preliminary evidence for lavender as an anxiolytic agent through various routes of administration. Our goal is to elucidate the best route of administration for lavender as a treatment for anxiety.

METHODS

Thirteen electronic search engines were systematically scanned for relevant publications. The relevant articles were included after the title and abstract screening followed by the full-text screening. This study included randomized control trials reporting lavender for the treatment of anxiety. The protocol was registered in PROSPERO (CRD42017076711). Frequentist network meta-analysis and Bayesian meta-regression were conducted to report the best treatment modality and the effect of covariates on the effectiveness as an anxiolytic. Treatment arms were ordered according P-scores, where higher P-score indicates better treatment choice.

RESULTS

Forty studies were eligible for qualitative analysis, and 32 were included in quantitative analysis. Lavender aromatherapy was the best approach for the treatment of anxiety among other lavender modalities at the first week recording [Standardized Mean Difference (SMD) = -0.57, 95% CI (-1.14-0.01), P-score = 0.72], in addition to achieve at the first time points [SMD = -0, 95% CI (-0.97 ̶ -0.16), P-score = 0.69], compared to placebo; however, lavender massage along with foot bath were found to be the most efficacious for anxiety treatment at the study endpoint [SMD = -1.10, 95% CI = (-7.41 ̶ 5.21), P-score = 0.65]. Furthermore, network meta-regression revealed that the duration of therapy influenced treatment, suggesting Silexan (oral lavender) 80 mg (first rank probability = .116) as the favorable option for anxiety in long-term treatment.

CONCLUSIONS

Lavender aromatherapy is, clinically, superior in short-duration, while Silexan (oral lavender) 80 mg is preferable for long-term treatment of anxiety.

Transcriptome profiling of spike provides expression features of genes related to terpene biosynthesis in lavender

Lavender (Lavandula angustifolia) is an important economic plant because of the value of its essential oil (EO). The Yili Valley in Xinjiang has become the largest lavender planting base in China. However, there is a lack of research on the gene expression regulation of EO biosynthesis and metabolism in local varieties. Here, de novo transcriptome analysis of inflorescence of three development stages from initial flower bud to flowering stage 50% from two lavender cultivars with contrasting EO production revealed the dynamics of 100,177 differentially expressed transcripts (DETs) in various stages of spike development within and across the cultivars. The lavender transcriptome contained 77 DETs with annotations related to terpenoid biosynthesis. The expression profiles of the 27 genes involved in the methylerythritol phosphate (MEP) pathway, 22 genes in the mevalonate (MVA) pathway, 28 genes related to monoterpene and sesquiterpene biosynthesis during inflorescence development were comprehensively characterized, and possible links between the expression changes of genes and contents of EO constituents were explored. The upregulated genes were mainly concentrated in the MEP pathway, while most genes in the MVA pathway were downregulated during flower development, and cultivars with a higher EO content presented higher expression of genes in the MEP pathway, indicating that EOs were chiefly produced through the MEP pathway. Additionally, MYB transcription factors constituted the largest number of transcripts in all samples, suggesting their potential roles in regulating EO biosynthesis. The sequences and transcriptional patterns of the transcripts will be helpful for understanding the molecular basis of lavender terpene biosynthesis.

Effects of diet on skin sensitization by nickel, poison ivy, and sesquiterpene lactones

Skin contact or exposure to sensitizers often occurs as a consequence of occupational exposures (e.g. poison ivy in forestry), wearing jewelry (e.g. nickel), or use of cosmetics (e.g. fragrances). However, many of the known skin sensitizers or their chemical variants are also consumed orally through foods or other sources. Since oral exposure to antigenic substances can lead to tolerance, consumption of sensitizers may impact the development and potency of skin sensitization, especially if the sensitizer is consumed early in life, prior to the first skin contact. To address this issue, we have reviewed human clinical and epidemiological literature relevant to this subject and evaluated whether early oral exposures to relevant sensitizers, or their chemical variants, are associated with reduced prevalence of skin sensitization to three main allergic sensitizers - nickel, urushiols of poison ivy, and sesquiterpene lactones of chrysanthemum and other plants.

Cloning and functional characterization of a floral repressor gene from Lavandula angustifolia

Using RNA-Seq, we identified genes involved in floral development in lavenders and functionally characterized the floral repressor LaSVP. The molecular aspects of flower initiation and development have not been adequately investigated in lavender (Lavandula). In order to identify genes that control these processes, we employed RNA-Seq to obtain sequence information for transcripts originating from the vegetative shoot apical meristem (SAM) and developing inflorescence tissues of Lavandula angustifolia and Lavandula × intermedia plants, and assemble a comprehensive transcriptome of 105,294 contigs. Homology-based annotation provided gene ontology terms for the majority of transcripts, including over 100 genes homologous to those that control flower initiation and organ identity in Arabidopsis thaliana. Expression analysis revealed that most of these genes are differentially expressed during flower development. For example, LaSVP, a homolog of the floral repressor SHORT VEGETATIVE PHASE (SVP), was strongly expressed in vegetative SAM compared to developing flowers, implicating its potential involvement in flowering repression in lavender. To investigate LaSVP further, we constitutively expressed the gene in transformed A. thaliana plants, evaluating its effects on flower initiation and morphology. Expression of the LaSVP in A. thaliana delayed flowering and affected flower organ identity in a dosage-dependent manner. Two of the highest expressing lines produced sepals instead of petals and were sterile as they failed to develop proper seed pods. This study provides the foundation for future investigations aimed at elucidating flower initiation and development in lavender.

Production Technology of Phytopreparations Based on Essential Oils

The article provides an overview of phytopreparations technology based on essential oils, in particular: criteria for the selection of components, qualitative and quantitative compositions analyzes, parameters of the technological cycle of production of drugs, problems of standardization and quality control of stages of the production of original drugs. A number of standard samples based on terpenoids for phased quality control of the production of medicinal products are described, which are included in the European, Kazakhstan and Japanese pharmacopeias. The main countries producing essential oils and their components, as well as manufacturers of phytopreparations based on them are indicated. The modern technologies for the production of essential oils from plant materials are reviewed, namely: microwave and ultrasonic extractions, supercritical carbon dioxide extraction and micro-steam distillation with solid phase microextraction. The dosage forms of preparations based on essential oils (tablets, ointments, gels, oil solutions, suppositories, sprays, aerosols, nanocapsules), their relationship with bioavailability and therapeutic effect are discussed. Promising dosage forms that ensure dosage accuracy for the targeted action of drugs based on essential oils have been identified.

Determination of Various Drying Methods' Impact on Odour Quality of True Lavender (Lavandula angustifolia Mill.) Flowers

True lavender flowers (Lavandula angustifolia Mill.) is a critical source of essential oils and a flavouring agent used in numerous industries like foods, cosmetics and pharmaceuticals. Its main volatile constituents are linalool and linalyl acetate, which are commonly considered as main odour-active constituents (OACs). Nevertheless, the quality of true lavender flowers is highly dependent on its post-harvest treatment, mainly the preservation method. Recognising that drying is the most frequently used preservation method, the influence of various drying methods, including convective drying (CD) at 50, 60 and 70 °C, vacuum-microwave drying (VMD) with powers 240, 360 and 480 W and combined convective pre-drying at 60 °C followed by vacuum-microwave finish-drying with power 480 W (CPD-VMFD), on the quality of true lavender flowers was verified. The evaluation of influence was carried out by HS-SPME(HS, solid-phase microextraction), GC-MS, GC-MS-O (gas chromatography–mass spectrometry–olfactometry) techniques. Moreover, the sensory panel has assessed the sample odour quality. As a result, the optimal drying methods regarding the requirements for products were established. Overall, for total essential oil recovery, CD at 50 °C is the optimal drying method, while for odour quality concerning the sensory panel evaluation, VMD with power 360 W combined CPD-VMFD and CD at 50 °C is the optimal drying method.

Liquid and Vapour Phase of Lavandin (Lavandula × intermedia) Essential Oil: Chemical Composition and Antimicrobial Activity

Essential oils from Lavandula genus and the obtained hybrids are widely used for different purposes such as perfume production in the cosmetic field and for its biological properties. This is the first study on the liquid and vapour phase of Lavandula × intermedia "Grosso" essential oil grown in the Lazio Region, Italy, investigated using headspace coupled to gas chromatography and mass spectrometry (HS-GC/MS). The results showed the most abundant components were linalool and linalyl acetate, followed by 1,8-cineole and terpinen-4-ol, while lavandulyl acetate and borneol were identified as minor compounds, maintaining the same proportion in both the liquid and vapour phase. Furthermore, we tested lavandin liquid and vapour phase essential oil on gram-negative bacteria (Escherichia coli, Acinetobacter bohemicus, and Pseudomonas fluorescens) and gram-positive bacteria (Bacillus cereus and Kocuria marina).

The Effect of Aromatherapy by Lavender Oil on Infant Vaccination Pain: a Double Blind Randomized Controlled Trial

Introduction: Exposure to noxious stimuli can cause pain in infants. This study was conducted to evaluate the effects of the lavender oil inhalation on the pain resulting from the pentavalent vaccination. Methods: This clinical trial consisted of two groups: the lavender oil group with 42 infants and the placebo group with 57 infants. The healthy infants without congenital abnormalities in need of pentavalent vaccine also participated in our study. The infants started the lavender oil or placebo aromatherapy one minute before injection. The pain was assessed three times, using the Neonatal Infant pain Scale (NIPS): before vaccination, 15 s, and 5 min after vaccination. Also, the duration of crying was measured in both groups. Results: At baseline, the two groups were similar in relation to the NIPS scores. While, after 5 minutes, the NIPS score was significantly lower in the lavender group. Based on the repeated measures analysis, the NIPS score changed over time totally. However, the two groups were significantly different in relation to the NIPS score over time. The duration of crying was 75.47 (60.675) second in the lavender group and 105.22 (75.739) s in the control group. The statistical test showed a significant difference between the two groups. Conclusion: A low concentration of the lavender oil inhalation can reduce the pain and improve soothing in the infants with the pentavalent vaccine injection.

HS-SPME Analysis of True Lavender (Lavandula angustifolia Mill.) Leaves Treated by Various Drying Methods

True lavender (Lavandula angustifolia Mill.) is a widely used flavoring and medicinal plant, which strong aroma is mainly composed of linalool and linalyl acetate. The most valuable parts of the plant are the flowers, however leaves are also abundant in volatile constituents. One of the main factors responsible for its quality is the preservation procedure, which usually comes down to a drying process. For this reason an attempt to verify the influence of various drying methods (convective drying, vacuum-microwave drying and combined convection pre-drying with vacuum-microwave finishing drying) on the quality of true lavender leaves was carried out by determination of the volatile constituents profile by solid-phase microextraction (SPME) coupled with GC-MS technique. Total essential oil (EO) content was also verified. The study has revealed that the optimal drying method is strongly dependent on the purpose of the product. For flavoring properties convective drying at 60 °C is the most optimal method, while the best for preserving the highest amount of EO is vacuum-microwave drying at 480 W. Furthermore, SPME analysis had shown that drying may increase the value of true lavender leaves by significantly affecting the linalool to linalyl acetate to camphor ratio in the volatile profile.

Lavandula Essential Oils: A Current Review of Applications in Medicinal, Food, and Cosmetic Industries of Lavender

The global essential oil market has been steadily increasing in size over the past few years, and is estimated to reach ca. $7.5 billion USD per annum by 2018. Lavenders ( Lavandula; Lamiaceae) contribute significantly to this market, yielding ca. 1500 tons of essential oils which are primarily used in cosmetics, personal care products, and medicines. Recent literature indicates that these oils may also have applications in food preservation and pest control, among others. The medicinal and pharmaceutical properties of lavenders are chiefly due their essential oils, in particular the major essential oil constituents linalool and linalyl acetate, although certain activities have been attributed to the phenolic compounds. In addition, there is evidence that the major and minor essential oil constituents act synergistically to provide various biological effects. A substantial amount of current research focuses on evaluating the biological activities of lavender essential oils for potential use in traditional and complementary medicine, food systems, cosmetic and fragrance formulations, and insect control products. This review examines recent progress in these areas, and highlights the current and future implications for these economically and medicinally valuable plants.

Lavender- and lavandin-distilled straws: an untapped feedstock with great potential for the production of high-added value compounds and fungal enzymes

BACKGROUND

Lavender (Lavandula angustifolia) and lavandin (a sterile hybrid of L. angustifolia × L. latifolia) essential oils are among those most commonly used in the world for various industrial purposes, including perfumes, pharmaceuticals and cosmetics. The solid residues from aromatic plant distillation such as lavender- and lavandin-distilled straws are generally considered as wastes, and consequently either left in the fields or burnt. However, lavender- and lavandin-distilled straws are a potentially renewable plant biomass as they are cheap, non-food materials that can be used as raw feedstocks for green chemistry industry. The objective of this work was to assess different pathways of valorization of these straws as bio-based platform chemicals and fungal enzymes of interest in biorefinery.

RESULTS

Sugar and lignin composition analyses and saccharification potential of the straw fractions revealed that these industrial by-products could be suitable for second-generation bioethanol prospective. The solvent extraction processes, developed specifically for these straws, released terpene derivatives (e.g. τ-cadinol, β-caryophyllene), lactones (e.g. coumarin, herniarin) and phenolic compounds of industrial interest, including rosmarinic acid which contributed to the high antioxidant activity of the straw extracts. Lavender and lavandin straws were also suitable inducers for the secretion of a wide panel of lignocellulose-acting enzymes (cellulases, hemicellulases and oxido-reductases) from the white-rot model fungus Pycnoporus cinnabarinus. Interestingly, high amounts of laccase and several lytic polysaccharide monooxygenases were identified in the lavender and lavandin straw secretomes using proteomics.

CONCLUSIONS

The present study demonstrated that the distilled straws of lavender and lavandin are lignocellulosic-rich materials that can be used as raw feedstocks for producing high-added value compounds (antioxidants, aroma) and fungal oxidative enzymes, which represent opportunities to improve the decomposition of recalcitrant lignocellulose into biofuel. Hence, the structure and the physico-chemical properties of these straws clearly open new perspectives for use in biotechnological processes involving especially filamentous fungi. These approaches represent sustainable strategies to foster the development of a local circular bioeconomy.

Essential Oils and Their Constituents Targeting the GABAergic System and Sodium Channels as Treatment of Neurological Diseases

Essential oils and the constituents in them exhibit different pharmacological activities, such as antinociceptive, anxiolytic-like, and anticonvulsant effects. They are widely applied as a complementary therapy for people with anxiety, insomnia, convulsion, pain, and cognitive deficit symptoms through inhalation, oral administration, and aromatherapy. Recent studies show that essential oils are emerging as a promising source for modulation of the GABAergic system and sodium ion channels. This review summarizes the recent findings regarding the pharmacological properties of essential oils and compounds from the oils and the mechanisms underlying their effects. Specifically, the review focuses on the essential oils and their constituents targeting the GABAergic system and sodium channels, and their antinociceptive, anxiolytic, and anticonvulsant properties. Some constituents target transient receptor potential (TRP) channels to exert analgesic effects. Some components could interact with multiple therapeutic target proteins, for example, inhibit the function of sodium channels and, at the same time, activate GABAA receptors. The review concentrates on perspective compounds that could be better candidates for new drug development in the control of pain and anxiety syndromes.

Latitude and Altitude Influence Secondary Metabolite Production in Peripheral Alpine Populations of the Mediterranean Species Lavandula angustifolia Mill

Lavandula angustifolia Mill. has a great economic importance in perfumery, cosmetics, food manufacturing, aromatherapy, and pharmaceutical industry. This species finds its phytosociological optimum in the sub-Mediterranean region. Latitudinal and altitudinal gradients are expected to affect species diversification in peripheral alpine populations. In this study, phenotypic traits including morphometric parameters, volatile organic compounds (VOCs) and essential oils (EOs) were analyzed in lavender peripheral populations selected in order to explore different ecological conditions. Plants were cultivated under uniform conditions to observe variations due to the genetic adaptation to native environments and to exclude the short-term response to environmental factors. Results showed qualitatively and quantitatively intra-specific variations in secondary metabolites, mainly along the latitudinal gradient, while minor effect was attributable to the altitude. This latter affected more the morphometric parameters. As the latitude augmented, VOCs showed lower content of monoterpene hydrocarbon (mh) and higher content of oxygenated monoterpenes (om); whereas EOs showed higher content of mh and non-terpene derivatives (nt) and lower content of sesquiterpene hydrocarbons (sh). Lavender aroma and EO composition varied in every population, for a total of 88 and 104 compounds identified, respectively. Eleven and 13 compounds were responsible for 95% of the dissimilarity, with linalool, linalyl acetate and 1,8-cineole as major contributors. As the latitude augmented, linalool decreased and 1,8-cineole increased while linalyl acetate content was unaffected. These results are discussed with regards to the potential adoption of the lavender peripheral alpine populations for the improvement of quality and productivity of lavender cultivations, especially in mountainous areas.

Three new benzolactones from Lavandula angustifolia and their bioactivities

Three new benzolactones (1-3), together with four known ones (4-7), were isolated from the whole herb of Lavandula angustifolia. Their structures were established on the basis of detailed spectroscopic analysis (1D- and 2D-NMR, HRESIMS, UV, and IR) and comparison with data reported in the literature. New compounds were evaluated for their anti-tobacco mosaic virus (TMV) activities and cytotoxic activities. The results revealed that compounds 1-3 showed obvious anti-TMV activities with inhibition rates of 26.9, 30.2, and 28.4%, which were at the same grade as positive control. Compounds 1-3 also showed weak inhibitory activities against some tested human tumor cell lines with IC₅₀ values in the range of 32.1-7.6 μM.

Three new phenylpropanoids from Lavandula angustifolia and their bioactivities

Three new phenylpropanoids, 3-(3,4-dimethoxy-5-methylphenyl)-3-oxopropyl acetate (1), 3-hydroxy-1-(3,4-dimethoxy-5-methylphenyl)propan-1-one (2), and 3-hydroxy-1-(4-methylbenzo[d][1,3]dioxol-6-yl) propan-1-one (3), together with three known phenylpropanoids (4-6) were isolated from the whole plant of Lavandula angustifolia. Their structures were determined by means of HRESIMS and extensive 1D and 2D NMR spectroscopic studies. Compounds 1-6 were tested for their anti-tobacoo mosaic virus (TMV) activities and cytotoxicity activities. The results revealed that compounds 1-3 showed high anti-TMV activity with inhibition rate of 35.2, 38.4 and 33.9%. These rates are higher than that of positive control. The other compounds also showed potential anti-TMV activities with inhibition rates in the range of 26.8-28.9%, respectively. Compounds 1-6 also showed weak inhibitory activities against some tested human tumour cell lines with IC50 values in the range of 3.8-8.8 μM.

Essential Oils for Treatment for Onychomycosis: A Mini-Review

Onychomycosis are fungal infections affecting finger and toenails mainly caused by dermatophyte fungi and some Candida species. Low cure rates and frequent recurrence, development of a fungal resistance front to various antimicrobial agents topical and systemic, and an ineffective topical treatment make onychomycosis difficult to treat. Essential oils are excellent candidates for the topical treatment for onychomycosis because the development of resistance by fungi is rare, and the presence of side effects is low. They are composed of a complex variety of compounds, mainly terpenes, with low molecular weight, which may easily penetrate into the nail plate, finding the fungi elements. The complex mixture confers a broad antifungal spectrum of action, through interaction with biological membranes, interference in radical and enzymatic reaction of fungi cells. Essential oils may become the source of new therapeutic molecules, and the use of an essential oil incorporated into a topical formulation is an interesting, safe, and effective alternative for the treatment for onychomycosis. However, studies are needed to evaluate the efficacy of essential oils in the treatment for onychomycosis in vivo. This mini-review aims to present the potential use of essential oils for the treatment for onychomycosis, focusing on the last decade.