Serotonergic amplification of odor-evoked neural responses maps onto flexible behavioral outcomes

Behavioral responses to many odorants are not fixed but are flexible, varying based on organismal needs. How such variations arise and the role of various neuromodulators in achieving flexible neural-to-behavioral mapping is not fully understood. In this study, we examined how serotonin modulates the neural and behavioral responses to odorants in locusts (Schistocerca americana). Our results indicated that serotonin can increase or decrease appetitive behavior in an odor-specific manner. On the other hand, in the antennal lobe, serotonergic modulation enhanced odor-evoked response strength but left the temporal features or the combinatorial response profiles unperturbed. This result suggests that serotonin allows for sensitive and robust recognition of odorants. Nevertheless, the uniform neural response amplification appeared to be at odds with the observed stimulus-specific behavioral modulation. We show that a simple linear model with neural ensembles segregated based on behavioral relevance is sufficient to explain the serotonin-mediated flexible mapping between neural and behavioral responses.

Development and evaluation of eco-friendly carvacrol nanoemulsion as a sustainable biopesticide against bacterial leaf blight of cluster bean

BACKGROUND

The study of carvacrol plant antibacterial components has recently become a hot topic in modern farming. Carvacrol industrial applications are restricted by their physicochemical instability and partial solubility in water. In the present study, an ultrasonic emulsification method was used to prepare a carvacrol nanoemulsion (CAR-NE) employing nonionic surfactants. The CAR-NE was characterized using a dynamic light scattering (DLS) instrument and transmission electron microscopy (TEM). The goal of this work was nanoencapsulation of carvacrol to improve its aqueous solubility and preservation of the encapsulated compound against climatic conditions. Another aim of the present study was the evaluation of the growth-promoting effects and antibacterial potential of CAR-NE against bacterial leaf blight of cluster bean.

RESULTS

CAR-NE showed a hydrodynamic diameter, ZP and PDI index of 43.88 ± 4.30 nm, -47.8 ± 0.23 mV and 0.246 ± 0.04, respectively. The spherical shape morphology of CAR-NE was confirmed by TEM imaging. Minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of the CAR-NE were 20 and 160 μL mL-1 (respectively) against Xanthomonas axonopodis pv. cyamopsidis. Additionally, the antibacterial potential of CAR-NE was evaluated for controlling bacterial blight of cluster bean in fields. The disease severity in the negative control plants (water) was 84%, but that in the CAR-NE 160 (μL mL-1 ) was remarkably low at 14%, nearly the same as the positive control (streptomycin sulfate).

CONCLUSION

The shelf-life of CAR-NE was 2 months at room temperature without any appreciable changes in hydrodynamic diameter and zeta potential. Consequently, plants treated with CAR-NE 160 showed substantial improvement in plant growth. © 2023 Society of Chemical Industry.

The Anti-Biofilm Potential of Linalool, a Major Compound from Hedychium larsenii, against Streptococcus pyogenes and Its Toxicity Assessment in Danio rerio

The anti-biofilm and anti-virulence potential of the essential oil (E.O.) extracted from Hedychium larsenii M. Dan & Sathish was determined against Streptococcus pyogenes. A crystal violet assay was employed to quantify the biofilm. Linalool, a monoterpene alcohol from the E.O., showed concentration-dependent biofilm inhibition, with a maximum of 91% at a concentration of 0.004% (v/v). The AlamarBlueTM assay also confirmed Linalool's non-bactericidal anti-biofilm efficacy (0.004%). Linalool treatment impeded micro-colony formation, mature biofilm architecture, surface coverage, and biofilm thickness and impaired cell surface hydrophobicity and EPS production. Cysteine protease synthesis was quantified using the Azocasein assay, and Linalool treatment augmented its production. This suggests that Linalool destabilizes the biofilm matrix. It altered the expression of core regulons covRS, mga, srv, and ropB, and genes associated with virulence and biofilm formation, such as speB, dltA, slo, hasA, and ciaH, as revealed by qPCR analysis. Cytotoxicity analysis using human kidney cells (HEK) and the histopathological analysis in Danio rerio proved Linalool to be a druggable molecule against the biofilms formed by S. pyogenes. This is the first report on Linalool's anti-biofilm and anti-virulence potential against S. pyogenes.

Computational docking investigation of phytocompounds from bergamot essential oil against Serratia marcescens protease and FabI: Alternative pharmacological strategy

The rapid development of multi-drug resistant (MDR) pathogens adds urgency to search for novel and safe drugs having promising action on new and re-emerging infectious pathogens. Serratia marcescens is an MDR pathogen that causes several-healthcare associated infections. Curbing bacterial virulence, rather than inhibiting its growth, is a promising strategy to diminish the pathogenesis of infectious bacteria, reduce the development of antimicrobial resistance, and boost the host immune power to eradicate infections. Bergamot essential oil (BEO) is a remarkable source of promising therapeutics against pathogens. Therefore, the present investigation aimed to analyze the major phytocompounds from BEO against S. marcescens virulent proteins using in silico studies. The analysis of BEO phytocompounds was achieved by Gas chromatography-mass spectrometry (GC-MS) method. The molecular docking was carried out using the SP and XP docking protocol of the Glide program. The drug-likeness and pharmacokinetics properties (ADMET properties) were analyzed with SwissADME and pkCSM server. The results revealed that the major compounds present in BEO are Linalool (8.17%), D-Limonene (21.26%), and Linalyl acetate (26.91%). Molecular docking analysis revealed that these compounds docked strongly within the binding cavities of Serratia protease and FabI model which in turn curb the pathogenesis of this bacteria. Linalool interacted with the Serratia protease and FabI with a binding energy of - 3.130 kcal/mol and - 3.939 kcal/mol, respectively. Based on the pharmacokinetics findings all lead BEO phytocompounds appear to be promising drug candidates. Overall, these results represent a significant step in the development of plant-based compounds as a promising inhibitor of the virulent proteins of the MDR S. marcescens.

Insecticidal properties of Ocimum basilicum and Mentha piperita essential oils against South American Tomato moth, Phthorimaea absoluta (Meyrick) (Lepidoptera: Gelichiidae)

Phthorimaea absoluta (Meyrick) is one of the most destructive pests of tomato, causing 100% yield loss in the absence of control measures. The important method of managing the pest is by using synthetic insecticides. However, intermittent and indiscriminate uses of certain insecticides have negative effect on the environment. Use of herbal insecticides such as secondary metabolites and essential oils is a key for sustainable long term crop protection. Investigation on the insecticidal properties of Ocimum basilicum, Mentha piperita essential oils (EOs) and their constituents was carried out against P. absoluta. The M. piperita EO showed highest mortality (100%) of P. absoluta with LC₅₀ 1.78 μl/ml due to alloaromadendrene (27.99%), levomenthol (18.31%) and santolina triene (9.78%). The O. basilicum EO also had significant mortality (90%) effect with LC₅₀ 3.58 μl/ml due to humulene (32.31%), alpha farnesense (27.22%), estragole (19.24%) and 4-cerene (10.61%). Among binary compounds, levomenthol showed highest mortality (100%) having LC₅₀ 13.18 μl/ml followed by alpha-pinene (100%) with LC₅₀ 16.10 μl/ml, 4-cerene (95%) with LC₅₀ 38.20 μl/ml and alpha-phellandrene (90%) having LC₅₀ 46.83 μl/ml. The observed toxicity in all compounds was due to significant changes in the activity of esterases, glutathione S-transferase and acetylcholine esterases over the time. The present study suggests that O. basilium and M. piperita EOs would provide an additional approach for the management of P. absoluta over synthetic insecticides.

In Vitro and In Silico Evaluation of the Antimicrobial and Antioxidant Potential of Thymus pulegioides Essential Oil

The study was designed to analyze and evaluate the antioxidant and antibacterial properties of the essential oils of Thymus pulegioides L. grown in Western Romania. Thymus pulegioides L. essential oil (TPEO) was extracted by steam distillation (0.71% v/w) using a Craveiro-type apparatus. GC-MS investigation of the TPEO identified 39 different compounds, representing 98.46% of total oil. Findings revealed that thymol (22.89%) is the main compound of TPEO, followed by para-cymene (14.57%), thymol methyl ether (11.19%), isothymol methyl ether (10.45%), and beta-bisabolene (9.53%). The oil exhibits good antibacterial effects; C. parapsilosis, C. albicans, S. pyogenes, and S. aureus were the most sensitive strains. The antioxidant activity of TPEO was evaluated by peroxide and thiobarbituric acid value, 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), [2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium] (ABTS) radical scavenging assay, and beta-carotene/linoleic acid bleaching testing. The antioxidative data recorded reveal, for the first time, that TPEO inhibits primary and secondary oxidation products, in some particular conditions, better than butylated hydroxyanisole (BHA) with significant statistical difference (p < 0.05). Moreover, TPEO antioxidant capabilities in DPPH and ABTS assays outperformed alpha-tocopherol (p < 0.001) and delta-tocopherol (p < 0.001). Molecular docking analysis revealed that one potential target correlated with the TPEO antimicrobial activity was d-alanine-d-alanine ligase (DDl). The best scoring ligand, linalyl anthranilate, shared highly similar binding patterns with the DDl native inhibitor. Furthermore, molecular docking analysis also showed that the main constituents of TPEO are good candidates for xanthine oxidase and lipoxygenase inhibition, making the essential oil a valuable source for protein-targeted antioxidant compounds. Consequently, TPEO may represent a new potential source of antioxidant and antibacterial agents with applicability in the food and pharmaceutic industries.

Sustainable agricultural practices for food security and ecosystem services

The notion of food security is a global phenomenon that impinges on every human. Efforts to increase productivity and yields have historically degraded the environment and reduced biodiversity and ecosystem services, with the significant impact on the poor. Sustainable agriculture-farming in sustainable ways based on an understanding of ecosystem services-is a practical option for achieving global food security while minimizing further environmental degradation. Sustainable agricultural systems offer ecosystem services, such as pollination, biological pest control, regulation of soil and water quality, maintenance of soil structure and fertility, carbon sequestration and mitigation of greenhouse gas emissions, nutrient cycling, hydrological services, and biodiversity conservation. In this review, we discuss the potential of sustainable agriculture for achieving global food security alongside healthy ecosystems that provide other valuable services to humankind. Too often, agricultural production systems are considered separate from other natural ecosystems, and insufficient attention has been paid to how services can flow to and from agricultural production systems to surrounding ecosystems. This review also details the trade-offs and synergies between ecosystem services, highlights current knowledge gaps, and proposes areas for future research.

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.

Impact of Dietary Lavender Essential Oil on the Growth and Fatty Acid Profile of Breast Muscles, Antioxidant Activity, and Inflammatory Responses in Broiler Chickens

This study aimed to investigate the impact of dietary addition of lavender essential oil (Lavandula angustifolia L.) (LEO) on the growth performance, tissue histoarchitecture, and fatty acid profile in breast muscles, as well as blood biochemistry and immune expression of pro-inflammatory cytokines of broiler chickens. A total of 200 three-day-old broiler chickens (average body weight 101.3 ± 0.24 g) were assigned to a completely randomized design consisting of four dietary treatments (n = 50 per treatment, each replicate consisting of 10 birds) that included lavender essential oil at concentrations of 0 (control group), 200, 400, and 600 mg Kg−1 diet. The experiment lasted for 35 days. The results revealed that supplementation of lavender essential oil at 200, 400, or 600 mg/kg in broiler diets had no effect (p > 0.05) on the growth performance throughout the experimental periods (3−10, 11−23, and 24−35 days of age). According to the broken line regression model, the optimal level for dietary LEO addition was the 460 mg kg−1 diet based on the total body weight gain and feed conversion ratio results. The diets supplemented with lavender essential oil had no effect (p > 0.05) on the percentages of carcass yield or internal organs. Dietary addition of LEO significantly increased the percentages of omega-3 polyunsaturated fatty acids PUFA (n-3), omega-6 polyunsaturated fatty acids (n-6), and the n-3/n-6 ratio (p < 0.05) in the breast muscles of chickens in a level-dependent manner. The blood concentration of alanine aminotransferase was significantly increased in lavender essential oil at 600 mg kg−1 compared with other treatments. The dietary addition of LEO at 200, 400, and 600 mg kg−1 significantly reduced the malondialdehyde level. Still, they significantly increased the serum enzyme activities of total antioxidant capacity, catalase, superoxide dismutase, and the pro-inflammatory cytokine (interleukine-1 beta and interferon γ) compared with the unsupplemented group. The LEO-supplemented groups showed normal liver histomorphology as in the control group. However, the immunoexpression of the pro-inflammatory cytokine transforming growth factor β was significantly increased by increasing the level of LEO. It can be concluded that lavender essential oil can be included in broiler chicken diets up to 460 mg kg −1 with no positive effect on the bird’s growth. It can improve the antioxidant capacity and enrich the breast muscles with PUFA. An increased level of supplementation (600 mg kg−1) increased the inflammatory responses in broiler chickens.

Mechanisms underlying the inhibitory effects of linalool on Aspergillus flavus spore germination

Biogenic volatile organic compounds hold remarkable potential for controlling fungal decay in agro- and food products. Recently, we reported that linalool, the major volatile component of the Zanthoxylum schinifolium pericarp, showed great potential as a biofumigant to control Aspergillus flavus growth in postharvest grains. In this study, the inhibitory effects of linalool on A. flavus growth in stored grains and its underlying mechanism were investigated through transcriptomic and biochemical analyses. Linalool vapor at 800 μL/L can effectively prevent A. flavus growth in 22% moisture wheat grains. Linalool at 2 μL/mL completely inhibited the germination of A. flavus spores, and 10 μL/mL caused spore death. Scanning electron microscopy revealed that linalool treatment caused wrinkling and spore breakage. Transcriptomics showed that 3806 genes were significantly differentially expressed in A. flavus spores exposed to 2 μL/mL linalool, predominantly showing enrichment regarding the ribosome, DNA replication, glutathione metabolism, peroxisome, and MAPK signaling pathways. Flow cytometry showed that linalool treatment caused hyperpolarization of mitochondrial membrane potential. 4,6-Diamidino-2-phenylindole staining indicated that linalool caused DNA fragmentation in A. flavus spores, and monodansylcadaverine staining confirmed that linalool induced autophagy in A. flavus spores. We thus propose that linalool can damage the plasma membrane, cause mitochondrial dysfunction and DNA damage, and induce autophagy in A. flavus spores. These findings considerably improve our understanding of the mechanisms underlying the inhibitory effects of linalool on A. flavus, which is crucial regarding the development of applications to prevent postharvest grain spoilage due to A. flavus infestations. KEY POINTS: • The inhibitory potency of linalool on A. flavus spore germination was determined. • Transcriptomic analyses were performed to identify differentially expressed genes of A. flavus exposed to linalool. • A functional mechanism underlying the inhibitory effects of linalool on A. flavus spore germination is proposed.

Differential Survivability of Two Genetically Similar Salmonella Thompson Strains on Pre-harvest Sweet Basil (Ocimum basilicum) Leaves

Although conventionally considered an animal pathogen, recent evidence increasingly suggests that fresh produce may act as significant transmission vehicles and alternative hosts to Salmonella. This study reports the differential survivability of two genetically similar Salmonella Thompson strains (ST 889B and ST 688C) on the adaxial surface of pre-harvest basil (Ocimum basilicum) leaves. Upon inoculation, two distinct phenomena, a dried water-print or a macroscopic lesion, were observed within 24 h. ST 889B survived better than ST 688C on healthy-looking leaves without lesions, possibly due to its higher biofilm-forming ability. Both strains survived better on the leaves with lesions than on the healthy-looking leaves (ST 688C: 4.39 ± 0.68 vs. 2.18 ± 0.29; ST 889B: 4.78 ± 0.12 vs. 2.83 ± 0.18 log CFU per sample at 6 days post-inoculation). ST 889B caused the formation of lesions at a higher frequency [70/117 leaves (59.8%)] than ST 688C [35/96 leaves (36.5%)]. Thus, we highlighted two distinct Salmonella survival strategies in the basil pathosystem and demonstrated gene expression polymorphism (variations in the expression of the same set of genes) as an indispensable strategy in the colonization of plants as hosts by the human pathogens.

A review on the traditional uses, phytochemistry, and pharmacological activities of clove basil (Ocimum gratissimum L.)

In traditional medicine, Ocimum gratissimum (clove basil) is used in the treatment of various diseases such as diabetes, cancer, inflammation, anaemia, diarrhoea, pains, and fungal and bacterial infections. The present study reviewed the phytochemicals, essential oils, and pharmacological activities of O. gratissimum. The bioactive compounds extracted from O. gratissimum include phytochemicals (oleanolic acid, caffeic acid, ellagic acid, epicatechin, sinapic acid, rosmarinic acid, chlorogenic acid, luteolin, apigenin, nepetoidin, xanthomicrol, nevadensin, salvigenin, gallic acid, catechin, quercetin, rutin, and kaempfero) and essential oils (camphene, β-caryophyllene, α- and β-pinene, α-humulene, sabinene, β-myrcene, limonene, 1,8-cineole, trans-β-ocimene, linalool, α- and δ-terpineol, eugenol, α-copaene, β-elemene, p-cymene, thymol, and carvacrol). Various in vivo and in vitro studies have shown that O. gratissimum and its bioactive constituents possess pharmacological properties such as antioxidant, anti-inflammatory, anticancer, hepatoprotective, antidiabetic, antihypertensive, antidiarrhoeal, and antimicrobial properties. This review demonstrated that O. gratissimum has a strong preventive and therapeutic effect against several diseases. The effectiveness of O. gratissimum to ameliorate various diseases may be attributed to its antimicrobial and antioxidant properties as well as its capacity to improve the antioxidant systems. However, despite the widespread pharmacological activities of O. gratissimum, further experiments in human clinical trial studies are needed to establish effective and safe doses for the treatment of various diseases.

Synthesis of uniform submicron poly(lactic acid)-based particles/capsules by radical precipitation polymerization

Poly(l-lactic acid) (PLLA) is a well-known biopolymer, usually synthesized via step-growth or ring-opening polymerization from lactic acid or a lactide monomer, respectively. PLLA microspherical particles are produced by dispersion polymerization with a ring-opening lactide monomer using a particular copolymer chain as a stabilizer. This is not easy to achieve when dehydration is needed. Here, a robust and simple synthesis of a nearly monodisperse, submicron PLLA-based particle/capsule was proposed via radical precipitation polymerization without the use of surfactant. A commercial PLLA was first glycolyzed with ethylene glycol to obtain a low molecular weight glycolyzed PLLA (GPLLA). Then, the GPLLA was copolymerized with methacrylic acid and ethylene glycol dimethacrylate monomers using a benzoyl peroxide initiator. Active sites on the GPLLA backbone were generated by hydrogen abstraction of benzoyloxy radicals that further copolymerized before self-assembly to form the polymer particles. Uniform particle size of about 580 nm with a low polydispersity index (PDI) of 0.012 was obtained. This method was also implemented to produce nearly monodisperse capsules containing linalool. The particle size of PLLA-based capsules was about 280 nm with narrow particle size distribution (PDI of 0.120). The PLLA-based capsules effectively inhibited microbial growth of Staphylococcus aureus, Escherichia coli and Candida albicans and were not toxic to human cells.

An overview of health challenges in alternative poultry production systems

Due to consumer demand and changing welfare standards on health, ecology, equity, and safety concepts, poultry production has changed markedly over the past 20 y. One of the greatest changes to poultry production standards is now offering poultry limited access to the outdoors in alternative and organic poultry production operations. Although operations allowing access to the outdoors are still only a small portion of commercial poultry production, it may impact the gastrointestinal (GIT) health of the bird in different ways than birds raised under conventional management systems. The present review describes current research results in alternative systems by identifying how different poultry production operations (diet, environmental disruptive factors, diseases) impact the ecology and health of the GIT. Various research efforts will be discussed that illustrate the nutritional value of free-range forages and how forages could be beneficial to animal health and production of both meat and eggs. The review also highlights the need for potential interventions to limit diseases without using antibiotics. These alternatives could enhance both economics and sustainability in organic and free-range poultry production.

Synthetic Protein Scaffolds for Improving R-(-)-Linalool Production in Escherichia coli

R-(-)-Linalool is widely used in the pharmaceutical, agrochemical, and fragrance industries; however, its applications are limited owing to low yield and high cost of production. To improve the production efficiency of R-(-)-linalool in Escherichia coli, three enzymes [E. coli-derived isopentenyl diphosphate isomerase, Abies grandis-derived geranyl diphosphate synthase, and Streptomyces clavuligerus-derived (3R)-linalool synthases] were physically colocalized to synthetic complexes using synthetic protein scaffolds of GTPase-binding domain, Src homology 3, and PSD95/DlgA/Zo-1. R-(-)-Linalool was produced at the highest concentration in the strain IGL114 containing a scaffold ratio of 1:1:4. By further optimizing the inducer, temperature, and glycerol concentration, the production titer of R-(-)-linalool in the shake flask was increased by approximately 10 times compared with that of the scaffold-free control and was 2.78 times the previously reported yield. The production in the fermenter was about 1.5 times the previous highest production. In general, the final strain accumulated 277.8 and 1523.2 mg/L R-(-)-linalool under the conditions of shake-flask and fed-batch fermentation, respectively. This study provides a foundation for the assembly of bacterial intracellular protein scaffolds.

Chemical Composition and Pharmacological Evaluation and of Toddalia asiatica (Rutaceae) Extracts and Essential Oil by in Vitro and in Silico Approaches

Toddalia asiatica (L.) Lam. is extensively used in traditional medicinal systems by various cultures. Despite its frequent use in traditional medicine, there is still a paucity of scientific information on T. asiatica growing on the tropical island of Mauritius. Therefore, the present study was designed to appraise the pharmacological and phytochemical profile of extracts (methanol, ethyl acetate and water) and essential oil obtained from aerial parts of T. asiatica. Biological investigation involved the evaluation of in vitro antioxidant and enzyme inhibitory potentials. The chemical profile of the EO was determined using gas chromatography coupled to mass spectrometry (GC/MS) analysis, while for the extracts, the total phenolic (TPC) and flavonoid content were quantified as well as their individual phenolic compounds by LC/MS/MS. Quinic acid, fumaric acid, chlorogenic acid, quercitrin and isoquercitrin were the main compounds in the extracts. Highest total phenolic (82.5±0.94 mg gallic acid equivalent (GAE/g)) and flavonoid (43.8±0.31 mg rutin equivalent (RE/g)) content were observed for the methanol extract. The GC/MS analysis has shown the presence of 26 compounds with linalool (30.9 %), linalyl acetate (20.9 %) and β-phellandrene (7.9 %) being most abundant components in the EO. The extracts and EO showed notable antioxidant properties, with the methanol extract proved to be superior source of antioxidant compounds. Noteworthy anti-acetylcholinesterase (AChE) and anti-butyrylcholinesterase (BChE) effects were recorded for the tested samples, while only the methanol and ethyl acetate extracts were active against tyrosinase. With respect to antidiabetic effects, the extracts and EO were potent inhibitors of α-glucosidase, while modest activity was recorded against α-amylase. Docking results showed that linalyl acetate has the highest affinity to interact with the active site of BChE with docking score of -6.25 kcal/mol. The findings amassed herein act as a stimulus for further investigations of this plant as a potential source of bioactive compounds which can be exploited as phyto-therapeutics.

Comprehensive Characterization of Linalool-HP-β-Cyclodextrin Inclusion Complexes

The objective of the present study is to obtain linalool- cyclodextrin (CDs) solid complexes for possible applications in the food industry. For this purpose, a detailed study of linalool complexation was carried out at different pH values, to optimize the type of CDs and reaction medium that support the highest quantity of encapsulated linalool. Once demonstrated the ability of hydroxypropyl-β-cyclodextrin (HP-β-CDs), to form inclusion complexes with linalool (K_C = 921 ± 21 L mol⁻¹) and given their greater complexation efficacy (6.788) at neutral pH, HP-β-CDs were selected to produce solid inclusion complexes by using two different energy sources, ultrasounds and microwave irradiation, subsequently spraying the solutions obtained in the Spray Dryer. To provide scientific solidity to the experimental results, the complexes obtained were characterized by using different instrumental techniques in order to confirm the inclusion of linalool in the HP-β-CDs hydrophobic cavity. The linalool solid complexes obtained were characterized by using ¹H nuclear magnetic resonance (¹H-NMR) and 2D nuclear magnetic resonance (ROSEY), differential scanning calorimetry, thermogravimetry and Fourier transform infrared spectrometry. Moreover, the structure of the complex obtained were also characterized by molecular modeling.

Parkinson's disease a futile entangle of Mankind's credence on an herbal remedy: A review

Parkinson's disease (PD) is a disease of the human nervous system with an onset, in the sixth and seventh decades of the human life. Chiefly perceived as progressive degeneration of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc) with the ensued loss of dopamine in the striatum and the presence of Lewy bodies, consisting of α-synuclein agglomeration. In which the neuronal bridge between substantia nigra and striatum plays an advent role in the motor system. Dilapidation of these neurons results in dopamine depletion which in-turn makes hay to PD. Eventually, the etiology and pathogenesis of PD were still on a hike of dilemma. Traditional Chinese medicine (TCM), including Chinese herbal remedies, acupuncture, and manipulative therapies, is commonly used as an adjunctive therapy in different diseases, particularly neurological diseases, in Asian countries. Additionally, TCM might improve the prognoses and the quality of life of patients with PD because it induces less adverse drug reactions. The present review describes research on the various neuroprotective components and herbal extracts from herbal medicines in the context of addressing the effects of PD.

Efficient Biosynthesis of R-(-)-Linalool through Adjusting the Expression Strategy and Increasing GPP Supply in Escherichia coli

R-(-)-linalool is widely used in pharmaceutical, agrochemical, and fragrance industries. However, plant extraction furnishes only limited and unstable R-(-)-linalool yields that do not satisfy market demand. Therefore, a sustainable yet efficient and productive method is urgently needed. To induce the R-(-)-linalool biosynthesis pathway in Escherichia coli, we expressed several heterologous (3R)-linalool synthases (LISs) and then chose a suitable LIS from Streptomyces clavuligerus (bLIS) for further study. The bLIS expression was markedly elevated by using optimized ribosomal binding sites and protein fusion tags. To increase the geranyl diphosphate content, we tested various alterations in prenyltransferases and their mutants. The final strain accumulated 100.1 and 1027.3 mg L^-1 R-(-)-linalool under shake flask and fed-batch fermentation conditions, respectively. The latter is the highest reported R-(-)-linalool yield to date. This work could lay theoretical and empirical foundations for engineering terpenoid pathways and optimizing other metabolic pathways.

Use of Starch Granules Enriched with Carvacrol for the Lesser Mealworm, Alphitobius diaperinus Control in Chicken House: Effects on Insects and Poultry

The aim of this study was to investigate the effect of starch granules enriched with carvacrol and mixed with straw pellets (as poultry litter) on the mortality of larvae and adults of the lesser mealworm, Alphitobius diaperinus Panzer, a cosmopolitan pest inhabiting chicken houses in vast numbers worldwide. Additionally, the effect of starch granules on the growth parameters and survival of broiler chickens exposed to treated litter was examined. In this study, granules containing 3, 5, and 10% carvacrol was used. In a simulated chicken house bioassay, this material was mixed with pellets in three different proportions: 30/70%, 40/60%, and 50/50% (granules/pellets, respectively). On this medium, young larvae (approximately 10 days old), older larvae (last stage before pupa), and unsexed 7–10 days old adults of the lesser mealworm, with access to food, were colonized. Experiments were performed at 29°C in the dark. The study shows that poultry litter with the addition of starch granules enriched with 10% of carvacrol in the proportion of 40:60% (granules:pellets) appears to be the optimal medium applicable to broiler houses for A. diaperinus control. In this environment, all larvae and adults died within 3–4 days and the overall development of the experimental chickens was similar to that of the control. However, the feed conversion rate was slightly higher in the treated group (1.72) than in the control group (1.56). The average final body weight in the treated group was 100 g lower than that in the control group (the differences were not statistically significant).

A Comparative Study of the in Vitro Antimicrobial and Synergistic Effect of Essential Oils from Laurus nobilis L. and Prunus armeniaca L. from Morocco with Antimicrobial Drugs: New Approach for Health Promoting Products

Laurus nobilis L. (laurel, Lauraceae) and Prunus armeniaca L. (apricot, Rosaceae) are important industrial crops and display significant biological properties, including antimicrobial activity. In this work, essential oils (EOs) prepared from the leaves of both species from Morocco were evaluated for the first time for possible synergistic in vitro antibacterial and antifungal effects with some conventional antimicrobial drugs, namely fluconazole, ciprofloxacin and vancomycin. Samples were further evaluated for chemical composition by gas chromatography–mass spectrometry (GC-MS). The main volatile compounds detected in L. nobilis were eucalyptol (40.85%), α-terpinyl acetate (12.64%) and methyl eugenol (8.72%), while P. armeniaca was dominated essentially by (Z)-phytol (27.18%), pentacosane (15.11%), nonacosane (8.76%) and benzaldehyde (7.25%). Regarding antimicrobial activity, both EOs inhibited significantly all the microorganisms tested. The EO from L. nobilis had the highest activity, with minimal inhibitory concentrations (MICs) ranging from 1.39 to 22.2 mg/mL for bacteria and between 2.77 and 5.55 mg/mL for yeasts. Conversely, the combination of the studied EOs with ciprofloxacin, vancomycin and fluconazol resulted in a noteworthy decrease in their individual MICs. In fact, of the 32 interactions tested, 23 (71.87%) demonstrated total synergism and 9 (28.12%) a partial synergistic interaction. The EO from L. nobilis exhibited the highest synergistic effect with all the antibiotics used, with fractional inhibitory concentration (FIC) index values in the range of 0.266 to 0.75 for bacteria, and between 0.258 and 0.266 for yeast. The synergistic interaction between the studied EOs and standard antibiotics may constitute promising anti-infective agents useful for treating diseases induced by antibiotic-resistant pathogens.

Linalool modulates dermatophyte susceptibility to azole drugs

This study investigated the monoterpene linalool and its resistance modulating activity involving ergosterol biosynthesis inhibitors (ketoconazole, fluconazole, and itraconazole) in strains of Microsporum spp. and Trichophyton spp. The minimum inhibitory concentration (MIC) of test-drugs were determined by microdilution. The modulating effect of linalool was evaluated by determining the MIC of the antifungals in the presence of subinhibitory concentrations of linalool. We also investigated the association effect (checkerboard) of linalool together with ketoconazole and itraconazole. The fungi became more sensitive to ketoconazole and itraconazole in the presence of linalool. The linalool and azole drug associations presented synergism.

Effects of supplementing broiler diets with coriander seed powder on growth performance, blood haematology, ileum microflora and economic efficiency

A total of 480 one-day-old Arbor Acres broiler chicks were randomly assigned to four dietary groups, each including six replicates (n = 20/replicate). Broilers in the first group (G1) were fed a basal diet without any additives (control). Broilers in groups 2, 3 and 4 (G2, G3 and G4) were fed a basal diet supplemented with 0.1%, 0.2% and 0.4% coriander (Coriandrum sativum L.) seed powder (CSP) respectively. Feeding trials lasted for 42 days, and after that growth, carcass traits, haematological parameters, gut microbiota and economic efficiency (EE) were evaluated. Final body weight (FBW), total weight gain (TWG), total feed intake (TFI) and red blood cell (RBC) counts of broilers in the G4 and G3 treatment groups were significantly higher (p < .05) compared with broilers in the G1 treatment group. The feed conversion ratio (FCR) was better (p < .05) in the G4 treatment group (1.72) than in the G1 treatment group (1.84). Broilers in CSP treatment groups had significantly higher haemoglobin (Hb) concentrations, packed cell volume (PCV) and platelet counts, and had lower (p < .05) Escherichia coli and Clostridium perfringens counts compared with broilers in the G1 treatment group. Dressing, liver, pancreas, bursa and thymus percentages were higher (p < .05) in broilers in the G4 (70.30, 3.18, 0.31, 0.10 and 0.32% respectively) treatment group, compared with broilers in the control (G1) group (66.57, 2.37, 0.23, 0.04 and 0.21% respectively). Broilers in treatment groups G4 and G3 had lower percentages of abdominal fat and lower total bacterial counts (p < .05) than broilers in treatment groups G2 and G1. The highest economic efficiency (EE) was found in treatment group G4, and EE in this group was 13.06% greater than in the control (G1) group.

Anti-inflammatory effects of linalool on ovalbumin-induced pulmonary inflammation

Linalool is a natural product present in fruits and aromatic plants with biological activities. Researchers have reported that the inhalation of linalool exerts anti-inflammatory activities. In this study, we examined the therapeutic effects of linalool on airway inflammation and mucus overproduction in mice with allergic asthma. Oral administration of linalool significantly inhibited the levels of eosinophil numbers, Th2 cytokines and immunoglobulin E (IgE) caused by ovalbumin (OVA) exposure. Linalool exerted preventive effects against the influx of inflammatory cells and mucus hypersecretion in the lung tissues. Linalool also dose-dependently decreased the levels of inducible nitric oxide synthase (iNOS) expression and protein kinase B (AKT) activation in the lung tissues. Linalool effectively downregulated the activation of mitogen-activated protein kinases (MAPKs) and nuclear factor-κB (NF-κB) caused by OVA exposure. Furthermore, linalool exerted inhibitory effect on OVA-induced airway hyperresponsiveness (AHR). In the in vitro study, the increased secretion of MCP-1 was attenuated with linalool treatment in lipopolysaccharide (LPS)-stimulated H292 airway epithelial cells. In conclusion, linalool effectively exerts a protective role in OVA-induced airway inflammation and mucus hypersecretion, and its protective effects are closely related to the downregulation of inflammatory mediators and MAPKs/NF-κB signaling.

A Combination of Linalool, Vitamin C, and Copper Synergistically Triggers Reactive Oxygen Species and DNA Damage and Inhibits Salmonella enterica subsp. enterica Serovar Typhi and Vibrio fluvialis

Inappropriate and disproportionate use of antibiotics is contributing immensely to the development of antibiotic resistance in bacterial species associated with food contamination. The use of natural products in combination can be a potent alternative hurdle strategy to inactivate foodborne pathogens. Here, we explored the pro-oxidant properties of essential oil linalool and vitamin C in combination with copper (LVC) in combating the foodborne pathogens Vibrio fluvialis and Salmonella enterica subsp. enterica serovar Typhi using a three-dimensional (3D) checkerboard microdilution assay. Antibacterial activity in terms of the MIC revealed that the triple combination exerted a synergistic effect compared to the effects of the individual constituents. The bactericidal effect of the triple combination was confirmed by a live/dead staining assay. Reactive oxygen species (ROS) measurements with the terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling assay and scanning electron microscopy imaging strongly suggested that the increase in ROS production is the underlying mechanism of the enhanced antibacterial potency of the LVC combination (linalool [1.298 mM], vitamin C [8 mM], copper [16.3 μM]). In addition, the hypersensitivity of oxidative stress regulator mutants (oxyR, katG, ahpC, and sodA mutants) toward LVC corroborated the involvement of ROS in cell death. Live/dead staining and changes in cellular morphology revealed that oxidative stress did not transform the cells into the viable but nonculturable (VBNC) state; rather, killing was associated with intracellular and extracellular oxidative burst. Furthermore, the LVC combination did not display toxicity to human cells, while it effectively reduced the pathogen levels in acidic fruit juices by 3 to 4 log CFU/ml without adversely altering the organoleptic properties. This study opens a new outlook for combinatorial antimicrobial therapy.IMPORTANCE There is a need to develop effective antibacterial therapies for mitigating bacterial pathogens in food systems. We used a 3D checkerboard assay to ascertain a safe synergistic combination of food-grade components: vitamin C, copper, and the essential oil linalool. Individually, these constituents have to be added in large amounts to exert their antibacterial effect, which leads to unwanted organoleptic properties. The triple combination could exceptionally inhibit foodborne Gram-negative pathogens like Vibrio fluvialis and Salmonella enterica subsp. enterica serovar Typhi at low concentrations (linalool, 1.298 mM; vitamin C, 8 mM; copper, 16.3 μM) and displayed potent microbial inhibition in acidic beverages. We found increased susceptibility in deletion mutants of oxidative stress regulators (oxyR, katG, ahpC, and sodA mutants) due to ROS generation by Fenton's chemistry. The results of this study show that it may be possible to use plant-based antimicrobials in synergistic combinations to control microbial contaminants.

Before it disappeared: ethnobotanical study of fleagrass (Adenosma buchneroides), a traditional aromatic plant used by the Akha people

BACKGROUND

Fleagrass, Adenosma buchneroides, is an aromatic perennial herb that occupies an important position in the life of the Akha people. They regard it as a tribal symbol and a gift of love. Fleagrass also has many medicinal uses, and there is considerable potential for its development as an insect repellent. Traditionally, Akha people plant it in swidden fields, but there are few swidden fields in China now. Therefore, the first question this study aims to answer is as follows: how is fleagrass planted and utilized now? At present, fleagrass is only reported to be used by Akha people in Mengla. We also try to understand the following questions: Is fleagrass used in nearby area? If so, how is fleagrass used in nearby area? Furthermore, why is fleagrass used in that way?

METHODS

From August 2016 to July 2018, field surveys were conducted six times. The ethnobotanical and ethnopharmacological uses of A. buchneroides in 13 Akha villages were investigated by means of semi-structured interviews. We assessed the responses of a total of 64 interviewees (32 men and 32 women; mean age, 58.6) from the Xishuangbanna Dai Autonomous Prefecture, southwest China, and from Phongsaly Province, Laos. To explain the bases for the ethnobotanical uses of fleagrass, we used Google Scholar, Web of Science, and China National Knowledge Infrastructure to review the bioactivities of the chemical constituents of A. buchneroides.

RESULTS

With the vanishing of swidden agriculture and the development of modern products, fleagrass cultivation is disappearing in China. However, most Akha people in Xishuangbanna still remember and yearn for its traditional uses, and Akha people in a nearby area (northern Laos) continue to plant and utilize it. We documented ten uses of A. buchneroides within five discrete categories. The whole plant of fleagrass has a distinct strong aroma, of which Akha villagers are particularly fond. Akha villagers mostly use this aromatic property as a decoration, perfume, and insect repellent. A. buchneroides is also used as a condiment and for medicinal and ritual purposes, including its use as a cure for insect bites, headaches, influenza, and diarrhoea, and as a part of pray ritual for a bumper harvest. From our literature review, we identified many major chemical compounds contained in the essential oil of A. buchneroides, including thymol, carvacrol, 3-carene, and p-cymene, which have insecticidal or insect-repellent, antimicrobial, and anti-inflammatory properties.

CONCLUSION

Fleagrass is an aromatic plant that is widely used by Aka people. Its chemical composition also has a variety of biological activities. With the vanishing of swidden agriculture and the development of modern products, fleagrass utilization in China is disappearing and its cultural importance is reduced. However, its economic and medicinal value is assignable.

Carvacrol and linalool co-loaded in β-cyclodextrin-grafted chitosan nanoparticles as sustainable biopesticide aiming pest control

Pesticides are the main tactics for pest control because they reduce the pest population very fast and their efficiency does not depend on abiotic factors. However, the indiscriminate use of these substances can speed up the development of resistant populations and causing environmental contamination. Therefore, alternative methods of pest control are sought, such as the use of botanical compounds. Nanoencapsulation of volatile compounds has been shown to be an important tool that can be used to overcome the lack of stability of these compounds. In this work, we describe the preparation and characterization of chitosan nanoparticles functionalized with β-cyclodextrin containing carvacrol and linalool. The toxicity and biological activity were evaluated. Decreases of toxicity were observed when the compounds were nanoencapsulated. The nanoparticles presented insecticidal activity against the species Helicoverpa armigera (corn earworm) and Tetranychus urticae (spider mite). In addition, repellent activity and reduction in oviposition were observed for the mites.

Chitosan nanoparticles functionalized with β-cyclodextrin: a promising carrier for botanical pesticides

Carvacrol and linalool are natural compounds extracted from plants and are known for their insecticidal and repellent activities, respectively. However, their low aqueous solubility, high photosensitivity, and high volatility restrict their application in the control of agricultural pests. The encapsulation of volatile compounds can be an effective way of overcoming such problems. Inclusion complexes between beta-cyclodextrin (β-CD) and carvacrol (CVC) or linalool (LNL) were investigated. Inclusion complexes were prepared by the kneading method. Both complexes presented 1:1 host:guest stoichiometry and the highest affinity constants were observed at 20 °C for both molecules. The nanoparticles containing carvacrol and linalool had mean diameters of 175.2 and 245.8 nm, respectively and high encapsulation efficiencies (<90%) were achieved for both compounds. Biological assays with mites (Tetranychus urticae) showed that the nanoparticles possessed repellency, acaricidal, and oviposition activities against this organism. Nanoencapsulated carvacrol and linalool were significantly more effective in terms of acaricidal and oviposition activities, while the unencapsulated compounds showed better repellency activity. The nanoformulations prepared in this study are good candidates for the sustainable and effective use of botanical compounds in agriculture, contributing to the reduction of environmental contamination, as well as promoting the effective control of pests in agriculture.

Enhancing linalool production by engineering oleaginous yeast Yarrowia lipolytica

In this study, stepwise increases in linalool production were obtained by combining metabolic engineering and process optimization of an unconventional oleaginous yeast Yarrowia lipolytica. The linalool synthetic pathway was successfully constructed by heterologously expressing a codon-optimized linalool synthase gene from Actinidia arguta in Y. lipolytica. To enhance linalool productivity, key genes involved in the mevalonate pathway were overexpressed in different combinations. Moreover, the overexpression of mutant ERG20^F88W-N119W gene resulted in further linalool production. A maximum linalool titre of 6.96±0.29mg/L was achieved in shake flasks, which was the highest level ever reported in yeasts.

Neurotoxic Effects of Linalool and β-Pinene on Tribolium castaneum Herbst

Effective, ethical pest control requires the use of chemicals that are highly specific, safe, and ecofriendly. Linalool and β-pinene occur naturally as major constituents of the essential oils of many plant species distributed throughout the world, and thus meet these requirements. These monoterpenes were tested as repellents against Tribolium castaneum, using the area preference method, after four hours of exposure and the effect transcriptional of genes associated with neurotransmission. Changes in gene expression of acetylcholinesterase (Ace1), GABA-gated anion channel splice variant 3a6a (Rdl), GABA-gated ion channel (Grd), glutamate-gated chloride channel (Glucl), and histamine-gated chloride channel 2 (Hiscl2) were assessed and the interaction with proteins important for the insect using in silico methods was also studied. For linalool and β-pinene, the repellent concentration 50 (RC₅₀) values were 0.11 µL/cm² and 0.03 µL/cm², respectively. Both compounds induced overexpression of Hiscl2 gen in adult insects, and β-pinene also promoted the overexpression of Grd and the Ace1 gene. However, β-pinene and linalool had little potential to dock on computer-generated models for GABA-gated ion channel LCCH3, nicotinic acetylcholine receptor subunits alpha1 and alpha2, and putative octopamine/tyramine receptor proteins from T. castaneum as their respective binding affinities were marginal, and therefore the repellent action probably involved mechanisms other than direct interaction with these targets. Results indicated that β-pinene was more potent than linalool in inducing insect repellency, and also had a greater capacity to generate changes in the expression of genes involved in neuronal transmission.

Protective effects of linalool against amyloid beta-induced cognitive deficits and damages in mice

AIM

Amyloid-beta (Aβ)-mediated neurotoxicity plays a pivotal role in the pathogenesis of Alzheimer's disease (AD), which induces oxidative stress and apoptosis. Linalool (LI) is a volatile monoterpene showing positive effect in AD treatment. This study was designed to research the protective effect of LI against neurotoxicity and cognitive deficits induced by Aβ_1-40 in mice.

MAIN METHODS

Aβ_1-40 (4μg) solution was injected in the bilateral hippocampus to induce cognitive deficits of mice. The protective effects of LI were evaluated by behavioral tests and the related mechanism was further explored by observing the apoptosis and oxidative stress changes in the hippocampus of mice.

KEY FINDINGS

LI (100mg/kg, i.p.) administration significantly improved the cognitive performance of model mice in Morris water maze test and step-through test. Meanwhile, LI effectively reversed the Aβ_1-40 induced hippocampal cell injury in histological examination, apoptosis in TUNEL assay, changes of oxidative stress indicators (SOD, GPX, AChE). Besides, the activated cleaved caspase (caspase-3, caspase-9) was suppressed and Nrf2, HO-1 expression was elevated by LI treatment.

SIGNIFICANCE

LI could attenuate cognitive deficits induced by Aβ, and the neuroprotective effect of LI might be mediated by alleviation of apoptosis, oxidative stress depending on activation of Nrf2/HO-1 signaling. We could assume that LI has the potential to be a neuroprotective substance for AD therapy.

Sedative effect of central administration of Coriandrum sativum essential oil and its major component linalool in neonatal chicks

Context Coriandrum sativum L. (Apiaceae) (coriander) is an herb grown throughout the world as a culinary, medicinal or essential crop. In traditional medicine, it is used for the relief of anxiety and insomnia. Systemic hydro-alcoholic and aqueous extract from aerial parts and seeds had anxiolytic and sedative action in rodents, but little is known about its central effect in chicks. Objective To study the effects of intracerebroventricular administration of essential oil from coriander seeds and its major component linalool on locomotor activity and emotionality of neonatal chicks. Materials and methods The chemical composition of coriander essential oil was determined by a gas-chromatographic analysis (> 80% linalool). Behavioural effects of central administration of coriander oil and linalool (both at doses of 0.86, 8.6 and 86 μg/chick) versus saline and a sedative diazepam dose (17.5 μg/chick, standard drug) in an open field test for 10 min were observed. Results Doses of 8.6 and 86 μg from coriander oil and linalool significantly decreased (p < 0.05) squares crossed number, attempted escapes, defecation number and distress calls, and significantly increased (p < 0.05) the sleeping posture on an open field compared with saline and were similar to the diazepam group. Discussion and conclusion The results indicate that intracerebroventricular injection of essential oil from Coriandrum sativum seeds induced a sedative effect at 8.6 and 86 μg doses. This effect may be due to monoterpene linalool, which also induced a similar sedative effect, and, therefore, could be considered as a potential therapeutic agent similar to diazepam.

Linalool reverses neuropathological and behavioral impairments in old triple transgenic Alzheimer's mice

Alzheimer's disease (AD) is an age-related progressive neurodegenerative disorder. Several types of treatments have been tested to block or delay the onset of the disease, but none have been completely successful. Diet, lifestyle and natural products are currently the main scientific focuses. Here, we evaluate the effects of oral administration of the monoterpene linalool (25 mg/kg), every 48 h for 3 months, on aged (21-24 months old) mice with a triple transgenic model of AD (3xTg-AD) mice. Linalool-treated 3xTg-AD mice showed improved learning and spatial memory and greater risk assessment behavior during the elevated plus maze. Hippocampi and amygdalae from linalool-treated 3xTg-AD mice exhibited a significant reduction in extracellular β-amyloidosis, tauopathy, astrogliosis and microgliosis as well as a significant reduction in the levels of the pro-inflammatory markers p38 MAPK, NOS2, COX2 and IL-1β. Together, our findings suggest that linalool reverses the histopathological hallmarks of AD and restores cognitive and emotional functions via an anti-inflammatory effect. Thus, linalool may be an AD prevention candidate for preclinical studies.