Chemical Composition and Effect against Skin Alterations of Bioactive Extracts Obtained by the Hydrodistillation of Eucalyptus globulus Leaves

Chemical Profiles and Biological Effects of Polyphenols in Eucalyptus Genus: A Comprehensive Review on Their Applications in Human Health and the Food Industry

The genus Eucalyptus is an important member of the family Myrtaceae. Eucalyptus plants contain unique and diverse phytochemicals, contributing to their remarkable ecological and economic values. Although the chemical components of several Eucalyptus food products (e.g., essential oil, honey, and wax) have been studied, research efforts are directed to other less characterized Eucalyptus phytochemicals, particularly polyphenols. Notably, some Eucalyptus polyphenols, such as formyl phloroglucinol meroterpenoids, have unique chemical structures with promising health-promoting effects. Thus, chemical characterization and biological evaluation of Eucalyptus polyphenols are critical to promoting their applications. Herein, this review provides a comprehensive summary of the phytochemical studies of Eucalyptus polyphenols and their biological activities, including antimicrobial, antiviral, anticancer, antioxidant, and anti-inflammatory effects. Eucalyptus polyphenols' structure-activity relationship is analyzed in the context of the development of their biological applications. In addition, the utilization of polyphenols from Eucalyptus plants in food preservation and production is summarized.

Therapeutic applications of eucalyptus essential oils

Eucalyptus essential oils (EEOs) have gained significant attention recently anticipated to their broad range of prospective benefits in various biological applications. They have been proven to have strong antibacterial properties against a variety of bacteria, fungi, and viruses. This makes them valuable in combating infections and supporting overall hygiene. The active compounds present in these oils can help alleviate inflammation, making them valuable in addressing inflammatory conditions such as arthritis, respiratory ailments, and skin disorders. Respiratory health benefits are another prominent aspect of EEOs. Inhalation of these oils can help promote clear airways, relieve congestion, and ease symptoms of respiratory conditions like coughs, colds, and sinusitis. They are often utilized in inhalation therapies and chest rubs. They can be used topically or in massage oils to alleviate muscle and joint pain. Furthermore, these oils have shown potential in supporting wound healing. Their antimicrobial activity helps prevent infection, while their anti-inflammatory and analgesic properties contribute to reducing inflammation and pain associated with wounds. In aromatherapy, EEOs are renowned for their invigorating and uplifting qualities, promoting mental clarity, relaxation, and stress relief. Overall, EEOs hold great promise in biological applications, offering a natural and versatile approach to promote health and well-being. Continued research and exploration of their therapeutic potential will further unveil their benefits and broaden their applications in various fields.

Natural Modulators of Key Signaling Pathways in Skin Inflammageing

Low-grade chronic inflammation without obvious infection is defined as "inflammageing" and a key driver of skin ageing. Although the importance of modulating inflammageing for treating skin diseases and restoring cutaneous homeostasis is increasingly being recognized. However, the mechanisms underlying skin inflammageing, particularly those associated with natural treatments, have not been systematically elucidated. This review explores the signaling pathways associated with skin inflammageing, as well as the natural plants and compounds that directly or indirectly target these pathways. Nine signaling pathways and 60 plants/constituents related to skin anti-inflammageing are discussed, exploring plant mechanisms to mitigate skin inflammageing. Common natural plants with anti-inflammageing activity are detailed by active ingredients, mechanisms, therapeutic potential, and quantitative effects on skin inflammageing modulation. This review strengthens our understanding of these botanical ingredients as natural interventions against skin inflammageing and provides directions for future research.

Effect of bioactive extracts from Eucalyptus globulus leaves in experimental models of Alzheimer's disease

Current therapies for Alzheimer's disease (AD) do not delay its progression, therefore, novel disease-modifying strategies are urgently needed. Recently, an increasing number of compounds from natural origin with protective properties against AD have been identified. Mixtures or extracts obtained from natural products containing several bioactive compounds have multifunctional properties and have drawn the attention because multiple AD pathways can be simultaneously modulated. This study evaluated the in vitro and in vivo effect of the essential oil (EO) obtained from the hydrodistillation of Eucalyptus globulus leaves, and an extract obtained from the hydrodistillation residual water (HRW). It was observed that EO and HRW have anti-inflammatory effect in brain immune cells modeling AD, namely lipopolysaccharide (LPS)- and amyloid-beta (Aβ)-stimulated microglia. In cell models that mimic AD-related neuronal dysfunction, HRW attenuated Aβ secretion and Aβ-induced mitochondrial dysfunction. Since the HRW's major components did not cross the blood-brain barrier, both EO and HRW were administered to the APP/PS1 transgenic AD mouse model by an intranasal route, which reduced cortical and hippocampal Aβ levels, and to rescue memory deficits and anxiety-like behaviors. Finally, HRW and EO were found to regulate cholesterol levels in aged mice after intranasal administration, suggesting that these extracts can reduce hypercholesterolemia and avoid risk for AD development. Overall, findings support a protective role of E. globulus extracts against AD‑like pathology and cognitive impairment highlighting the underlying mechanisms. These extracts obtained from underused forest biomass could be useful to develop nutraceutical supplements helpful to avoid AD risk and to prevent its progression.

Agroprospecting of Biowastes: Globe Artichoke (Cynara scolymus L. Cultivar Tema, Asteraceae) as Potential Source of Bioactive Compounds

Artichokes (Cynara scolymus L.) are valuable foods, thanks to their health benefits, but they generate significant waste during their production, harvesting, and processing, which poses sustainability issues. This study applied an agroprospecting approach to convert Tema artichoke biowaste (TB) into valuable resources, starting from a global perspective of the production chain to the targeted applications based on chemical and biological analysis. The major TB was identified in the outer bracts of the immature flower heads, which were collected throughout the harvesting season, extracted, and analyzed. The most abundant compounds were phenolic acids including chlorogenic acid and caffeoylquinic derivatives. Among flavonoids, cynaroside was the most abundant compound. Multivariate analysis distinguished batches by collection period, explaining 77.7% of the variance, with most compounds increasing in concentration later in the harvest season. Subsequently, TB extracts were analyzed for their potential in wound healing and anti-aging properties. Fibroblasts were used to assess the effect of selected extracts on cell migration through a scratch wound assay and on cellular senescence induced by etoposide. The results show a significant decrease in senescence-associated β-galactosidase activity, γH2AX nuclear accumulation, and both p53 and p21 protein levels. Overall, this study ascribes relevant anti-skin aging effects to TB, thus increasing its industrial value in cosmeceutical and nutraceutical applications.

Unlocking the Bioactive Potential and Exploring Novel Applications for Portuguese Endemic Santolina impressa

The infusion of Santolina impressa, an endemic Portuguese plant, is traditionally used to treat various infections and disorders. This study aimed to assess its chemical profile by HPLC-DAD-ESI-MSn and validate its anti-inflammatory potential. In addition, the antioxidant capacity and effects on wound healing, lipogenesis, melanogenesis, and cellular senescence, all processes in which a dysregulated inflammatory response plays a pivotal role, were unveiled. The anti-inflammatory potential was assessed in lipopolysaccharide (LPS)-stimulated macrophages, cell migration was determined using a scratch wound assay, lipogenesis was assessed on T0901317-stimulated keratinocytes and melanogenesis on 3-isobutyl-1-methylxanthine (IBMX)-activated melanocytes. Etoposide was used to induce senescence in fibroblasts. Our results point out a chemical composition predominantly characterized by dicaffeoylquinic acids and low amounts of flavonols. Regarding the infusion's bioactive potential, an anti-inflammatory effect was evident through a decrease in nitric oxide production and inducible nitric oxide synthase and pro-interleukin-1β protein levels. Moreover, a decrease in fibroblast migration was observed, as well as an inhibition in both intracellular lipid accumulation and melanogenesis. Furthermore, the infusion decreased senescence-associated β-galactosidase activity, γH2AX nuclear accumulation and both p53 and p21 protein levels. Overall, this study confirms the traditional uses of S. impressa and ascribes additional properties of interest in the pharmaceutical and dermocosmetics industries.

Plant Monoterpenes and Essential Oils as Potential Anti-Ageing Agents: Insights from Preclinical Data

Ageing is a natural process characterized by a time-dependent decline of physiological integrity that compromises functionality and inevitably leads to death. This decline is also quite relevant in major human pathologies, being a primary risk factor in neurodegenerative diseases, metabolic disorders, cardiovascular diseases and musculoskeletal disorders. Bearing this in mind, it is not surprising that research aiming at improving human health during this process has burst in the last decades. Importantly, major hallmarks of the ageing process and phenotype have been identified, this knowledge being quite relevant for future studies towards the identification of putative pharmaceutical targets, enabling the development of preventive/therapeutic strategies to improve health and longevity. In this context, aromatic plants have emerged as a source of potential bioactive volatile molecules, mainly monoterpenes, with many studies referring to their anti-ageing potential. Nevertheless, an integrated review on the current knowledge is lacking, with several research approaches studying isolated ageing hallmarks or referring to an overall anti-ageing effect, without depicting possible mechanisms of action. Herein, we aim to provide an updated systematization of the bioactive potential of volatile monoterpenes on recently proposed ageing hallmarks, and highlight the main mechanisms of action already identified, as well as possible chemical entity-activity relations. By gathering and categorizing the available scattered information, we also aim to identify important research gaps that could help pave the way for future research in the field.

Effect of Ferulago lutea (Poir.) Grande Essential Oil on Molecular Hallmarks of Skin Aging

With the increase in global life expectancy, maintaining health into old age becomes a challenge, and research has thus concentrated on various strategies which aimed to mitigate the effects of skin aging. Aromatic plants stand out as promising sources of anti-aging compounds due to their secondary metabolites, particularly essential oils (EOs). The aim of this study was to ascribe to Ferulago lutea EO several biological activities that could be useful in the context of skin aging. The EO was obtained using hydrodistillation and characterized by gas chromatography-mass spectrometry (GC/MS). The anti-inflammatory potential was assessed using lipopolysaccharide (LPS)-stimulated macrophages. The effect on cell migration was disclosed using scratch wound assay. Lipogenesis was induced using T0901317, hyperpigmentation with 3-isobutyl-1-methylxantine (IBMX) and senescence with etoposide. Our results show that the EO was characterized mainly by α-pinene and limonene. The EO was able to decrease nitric oxide (NO) release as well as iNOS and pro-IL-1β protein levels. The EO promoted wound healing while decreasing lipogenesis and having depigmenting effects. The EO also reduced senescence-associated β-galactosidase, p21/p53 protein levels and the nuclear accumulation of γH2AX. Overall, our study highlights the properties of F. lutea EO that make it a compelling candidate for dermocosmetics applications.

In Vitro and In Silico Activities of E. radiata and E. cinerea as an Enhancer of Antibacterial, Antioxidant, and Anti-Inflammatory Agents

Eucalyptus, a therapeutic plant mentioned in the ancient Algerian pharmacopeia, specifically two species belonging to the Myrtaceae family, E. radiata and E. cinerea, were investigated in this study for their antibacterial, antioxidant, and anti-inflammatory properties. The study used aqueous extracts (AE) obtained from these plants, and the extraction yields were found to be different. The in vitro antibacterial activity was evaluated using a disc diffusion assay against three typical bacterial strains. The results showed that the two extracts were effective against all three strains. Both extracts displayed significant antioxidant activity compared to BHT. The anti-inflammatory impact was evaluated using a protein (BSA) inhibition denaturation test. The E. radiata extract was found to inhibit inflammation by 85% at a concentration of 250 µg/mL, significantly higher than the Aspirin. All phytoconstituents present good pharmacokinetic characteristics without toxicity except very slight toxicity of terpineol and cineol and a maximum binding energy of -7.53 kcal/mol for its anti-TyrRS activity in silico. The study suggests that the extracts and their primary phytochemicals could enhance the efficacy of antibiotics, antioxidants, and non-steroidal anti-inflammatory drugs (NSAIDs). As pharmaceutical engineering experts, we believe this research contributes to developing natural-based drugs with potential therapeutic benefits.

In Vitro and In Vivo Antimelanogenesis Effects of Leaf Essential Oil from Agathis dammara

Agathis species are widely distributed around Southeast Asia, Australasia, South Pacific islands, and etc. Traditionally, Agathis species have been used as the folk medicines, the common ethnopharmacological uses of Agathis genus are the treatments of headache and myalgia. This study aims to investigate the chemical composition of Agathis dammara (Lamb.) Rich. leaf essential oil and to explore its antimelanogenesis effect. The chemical constituents of leaf essential oil are analyzed using gas chromatography-mass spectrometry (GC-MS), the major constituents of leaf essential oil are sesquiterpenoids. The major constituents are δ-cadinene (16.12%), followed by γ-gurjunene (15.57%), 16-kaurene (12.43%), β-caryophyllene (8.58%), germacrene D (8.53%), and γ-cadinene (5.33%). As for the in vitro antityrosinase activity, leaf essential oil inhibit the tyrosinase activity of mushroom when the substrate is 3,4-dihydroxyphenylalanine (L-DOPA). Leaf essential oil prevents tyrosinase from acting as diphenolase and catalyzing L-DOPA to dopaquinone, and converting into dark melanin pigments. A. dammara leaf essential oil also exhibits the in vivo antimelanogenesis effect, leaf essential oil reduces 43.48% of melanin formation in zebrafish embryos at the concentration of 50 μg/mL. Results reveal A. dammara leaf essential oil has the potential for developing the skin whitening drug and depigmentation ingredient for hyperpigmentary disorders.

How to Naturally Support the Immune System in Inflammation-Essential Oils as Immune Boosters

Efficient functionality of the immune system is needed to fight against the development of infectious diseases, including, among others, serious recurrent chronic infections. Research has shown that many modern common diseases, such as inflammatory bowel diseases and cardiovascular diseases, e.g., thromboembolism, cancer, obesity, or depression, are connected with inflammatory processes. Therefore, new, good stimulators of the immune system's response are sought. They include synthetic compounds as well as biological preparations such as lipopolysaccharides, enzymes, bacterial metabolites, and secondary metabolites of plants, demonstrating a multidirectional effect. Essential oils are characterized by many invaluable activities, including antimicrobial, antioxidant, anti-inflammatory, and immunostimulating. Essential oils may stimulate the immune system via the utilization of their constituents, such as antibodies, cytokines, and dendritic cells. Some essential oils may stimulate the proliferation of immune-competent cells, including polymorphonuclear leukocytes, macrophages, dendritic cells, natural killer cells, and B and T lymphocytes. This review is focused on the ability of essential oils to affect the immune system. It is also possible that essential oil components positively interact with recommended anti-inflammatory and antimicrobial drugs. Thus, there is a need to explore possible synergies between essential oils and their active ingredients for medical use.

Exploring the Traditional Uses of Thymbra capitata Infusion in Algarve (Portugal): Anti-Inflammatory, Wound Healing, and Anti-Aging

Inflammation plays a pivotal role in the resolution of infection or tissue damage. In addition, inflammation is considered a hallmark of aging, which in turn compromises wound healing. Thymbra capitata is an aromatic plant, whose infusion is traditionally used as an anti-inflammatory and wound-healing agent. In this study, a T. capitata infusion was prepared and characterized by HPLC-PDA-ESI-MSn and its safety profile determined by the resazurin metabolic assay. The anti-inflammatory potential was revealed in lipopolysaccharide (LPS)-stimulated macrophages by assessing nitric oxide (NO) release and levels of inducible nitric oxide synthase (iNOS) and the interleukin-1β pro-form (pro-IL-1β). Wound-healing capacity was determined using the scratch assay. The activity of senescence-associated β-galactosidase was used to unveil the anti-senescent potential, along with the nuclear accumulation of yH2AX and p21 levels. The antiradical potential was assessed by DPPH and ABTS scavenging assays. The infusion contains predominantly rosmarinic acid and salvianolic acids. The extract decreased NO, iNOS, and pro-IL-1β levels. Interestingly, the extract promoted wound healing and decreased β-galactosidase activity, as well as yH2AX and p21 levels. The present work highlights strong antiradical, anti-inflammatory, and wound healing capacities, corroborating the traditional uses ascribed to this plant. We have described, for the first time for this extract, anti-senescent properties.

Eucalyptus globulus Mediated Green Synthesis of Environmentally Benign Metal Based Nanostructures: A Review

The progress in nanotechnology has effectively tackled and overcome numerous global issues, including climate change, environmental contamination, and various lethal diseases. The nanostructures being a vital part of nanotechnology have been synthesized employing different physicochemical methods. However, these methods are expensive, polluting, eco-unfriendly, and produce toxic byproducts. Green chemistry having exceptional attributes, such as cost-effectiveness, non-toxicity, higher stability, environment friendliness, ability to control size and shape, and superior performance, has emerged as a promising alternative to address the drawbacks of conventional approaches. Plant extracts are recognized as the best option for the biosynthesis of nanoparticles due to adherence to the environmentally benign route and sustainability agenda 2030 of the United Nations. In recent decades, phytosynthesized nanoparticles have gained much attention for different scientific applications. Eucalyptus globulus (blue gum) is an evergreen plant belonging to the family Myrtaceae, which is the targeted point of this review article. Herein, we mainly focus on the fabrication of nanoparticles, such as zinc oxide, copper oxide, iron oxide, lanthanum oxide, titanium dioxide, magnesium oxide, lead oxide, nickel oxide, gold, silver, and zirconium oxide, by utilizing Eucalyptus globulus extract and its essential oils. This review article aims to provide an overview of the synthesis, characterization results, and biomedical applications of nanoparticles synthesized using Eucalyptus globulus. The present study will be a better contribution to the readers and the students of environmental research.

Safety and efficacy of a feed additive consisting of an essential oil derived from Eucalyptus globulus Labill. (eucalyptus oil) for all animal species (FEFANA asbl)

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of an essential oil from the leaves and twigs of Eucalyptus globulus Labill. (eucalyptus oil) when used as a sensory additive in feed and water for drinking for all animal species. The FEEDAP Panel concluded that the use of eucalyptus oil is safe at the following concentrations in complete feed: 12 mg/kg for chickens for fattening, 18 mg/kg for laying hens, 16 mg/kg for turkeys for fattening, 22 mg/kg for piglets, 26 mg/kg for pigs for fattening, 32 mg/kg for sows, 55 mg/kg for veal calves (milk replacer), 48 mg/kg for cattle for fattening, sheep, goats and horses, 31 mg/kg for dairy cows, 19 mg/kg for rabbits, 55 mg/kg for salmonids, 58 mg/kg for dogs, 10 mg/kg for cats and 75 mg/kg for ornamental fish. These conclusions were extrapolated to other physiologically related species. For any other species, the additive was considered safe at 10 mg/kg complete feed. No concerns for consumers were identified following the use of eucalyptus oil up to the highest safe level in feed. The additive under assessment should be considered as irritant to skin and eyes and the respiratory tract and as a skin sensitiser. The use of eucalyptus oil at the proposed use level in feed was not expected to pose a risk for the environment. Since E. globulus and its preparations were recognised to flavour food and its function in feed would be essentially the same as that in food, no further demonstration of efficacy was considered necessary.

Nano-Chitosan/Eucalyptus Oil/Cellulose Acetate Nanofibers: Manufacturing, Antibacterial and Wound Healing Activities

Accelerated wound healing in infected skin is still one of the areas where current therapeutic tactics fall short, which highlights the critical necessity for the exploration of new therapeutic approaches. The present study aimed to encapsulate Eucalyptus oil in a nano-drug carrier to enhance its antimicrobial activity. Furthermore, in vitro, and in vivo wound healing studies of the novel nano-chitosan/Eucalyptus oil/cellulose acetate electrospun nanofibers were investigated. Eucalyptus oil showed a potent antimicrobial activity against the tested pathogens and the highest inhibition zone diameter, MIC, and MBC (15.3 mm, 16.0 μg/mL, and 256 μg/mL, respectively) were recorded against Staphylococcus aureus. Data indicated a three-fold increase in the antimicrobial activity of Eucalyptus oil encapsulated chitosan nanoparticle (43 mm inhibition zone diameter against S. aureus). The biosynthesized nanoparticles had a 48.26 nm particle size, 19.0 mV zeta potential, and 0.45 PDI. Electrospinning of nano-chitosan/Eucalyptus oil/cellulose acetate nanofibers was conducted, and the physico-chemical and biological properties revealed that the synthesized nanofibers were homogenous, with a thin diameter (98.0 nm) and a significantly high antimicrobial activity. The in vitro cytotoxic effect in a human normal melanocyte cell line (HFB4) proved an 80% cell viability using 1.5 mg/mL of nano-chitosan/Eucalyptus oil/cellulose acetate nanofibers. In vitro and in vivo wound healing studies revealed that nano-chitosan/Eucalyptus oil/cellulose acetate nanofibers were safe and efficiently enhanced the wound-healing process through enhancing TGF-β, type I and type III collagen production. As a conclusion, the manufactured nano-chitosan/Eucalyptus oil/cellulose acetate nanofiber showed effective potentiality for its use as a wound healing dressing.

Effect of Thymbra capitata (L.) Cav. on Inflammation, Senescence and Cell Migration

Aromatic plants are reported to display pharmacological properties, including anti-aging. This work aims to disclose the anti-aging effect of the essential oil (EO) of Thymbra capitata (L.) Cav., an aromatic and medicinal plant widely used as a spice, as well as of the hydrodistillation residual water (HRW), a discarded by-product of EO hydrodistillation. The phytochemical characterization of EO and HRW was assessed by GC-MS and HPLC-PDA-ESI-MSⁿ, respectively. The DPPH, ABTS, and FRAP assays were used to disclose the antioxidant properties. The anti-inflammatory potential was evaluated using lipopolysaccharide-stimulated macrophages by assessing NO production, iNOS, and pro-IL-1β protein levels. Cell migration was evaluated using the scratch wound assay, and the etoposide-induced senescence was used to assess the modulation of senescence. The EO is mainly characterized by carvacrol, while the HRW is predominantly characterized by rosmarinic acid. The HRW exerts a stronger antioxidant effect in the DPPH and FRAP assays, whereas the EO was the most active sample in the ABTS assay. Both extracts reduce NO, iNOS, and pro-IL-1β. The EO has no effect on cell migration and presents anti-senescence effects. In opposition, HRW reduces cell migration and induces cellular senescence. Overall, our study highlights interesting pharmacological properties for both extracts, EO being of interest as an anti-aging ingredient and HRW relevant in cancer therapy.

A Hydrophilic Sulfated Resveratrol Derivative for Topical Application: Sensitization and Anti-Allergic Potential

Resveratrol (RSV), a naturally occurring metabolite, is widely used in skincare products, but its hydrophobicity impairs its own incorporation into cosmetic formulations. RSV-GS is a synthetic hydrophilic sulfated glycosylated derivative inspired by marine natural products that present a lower cytotoxicity than RSV while exhibiting similar levels of bioactivity. Herein, we predict the skin sensitization potential of this new compound using an in vitro approach based on the OECD 442E guideline. Furthermore, the anti-allergic potential of RSV-GS was also disclosed. The monocyte THP-1 cell line was stimulated with RSV and RSV-GS in the presence or absence of the extreme skin allergen 1-fluoro-2,4-dinitrobenzene (DNFB). The results demonstrated that RSV-GS alone (500 µM) evoked a relative fluorescence index (RFI) lower than the thresholds established by the OECD guideline for CD54 (200%) and CD86 (150%), indicating the absence of a skin sensitization potential. Interestingly, in the presence of the skin allergen DNFB, RSV-GS exhibited the ability to rescue the DNFB-induced maturation of THP-1 cells, with RFI values lower than those for RSV, suggesting the potential of RSV-GS to mitigate skin sensitization evoked by allergens and, consequently, allergic contact dermatitis. These results open new avenues for the use of RSV-GS as a safe and anti-allergic active cosmetic ingredient.

Exploiting the Integrated Valorization of Eucalyptus globulus Leaves: Chemical Composition and Biological Potential of the Lipophilic Fraction before and after Hydrodistillation

E. globulus leaves have been mainly exploited for essential oil recovery or for energy generation in industrial pulp mills, neglecting the abundance of valuable families of extractives, namely, triterpenic acids, that might open new ways for the integrated valorization of this biomass. Therefore, this study highlights the lipophilic characterization of E. globulus leaves before and after hydrodistillation, aiming at the integrated valorization of both essential oils and triterpenic acids. The lipophilic composition of E. globulus leaves after hydrodistillation is reported for the first time. Extracts were obtained by dichloromethane Soxhlet extraction and analyzed by gas chromatography-mass spectrometry. In addition, their cytotoxicity on different cell lines representative of the innate immune system, skin, liver, and intestine were evaluated. Triterpenic acids, such as betulonic, oleanolic, betulinic and ursolic acids, were found to be the main components of these lipophilic extracts, ranging from 30.63–37.14 g kg−1 of dry weight (dw), and representing 87.7–89.0% w/w of the total content of the identified compounds. In particular, ursolic acid was the major constituent of all extracts, representing 46.8–50.7% w/w of the total content of the identified compounds. Other constituents, such as fatty acids, long-chain aliphatic alcohols and β-sitosterol were also found in smaller amounts in the studied extracts. This study also demonstrates that the hydrodistillation process does not affect the recovery of compounds of greatest interest, namely, triterpenic acids. Therefore, the results establish that this biomass residue can be considered as a promising source of value-added bioactive compounds, opening new strategies for upgrading pulp industry residues within an integrated biorefinery context.

Advances in the Phytochemical Characterisation and Bioactivities of Salvia aurea L. Essential Oil

The Salvia L. genus (Lamiaceae) is largely used in the pharmaceutical and food industry. Several species of biological relevance are extensively employed in traditional medicine, including Salvia aurea L. (syn. S. africana-lutea L.), which is used as a traditional skin disinfectant and in wounds as a healing remedy; nevertheless, these properties have not been validated yet. The aim of the present study is to characterise S. aurea essential oil (EO), unveiling its chemical composition and validating its biological properties. The EO was obtained by hydrodistillation and subsequently analysed by GC-FID and GC-MS. Different biological activities were assessed: the antifungal effect on dermatophytes and yeasts and the anti-inflammatory potential by evaluating nitric oxide (NO) production and COX-2 and iNOS protein levels. Wound-healing properties were assessed using the scratch-healing test, and the anti-aging capacity was estimated through the senescence-associated beta-galactosidase activity. S. aurea EO is mainly characterised by 1,8-cineole (16.7%), β-pinene (11.9%), cis-thujone (10.5%), camphor (9.5%), and (E)-caryophyllene (9.3%). The results showed an effective inhibition of the growth of dermatophytes. Furthermore, it significantly reduced protein levels of iNOS/COX-2 and simultaneously NO release. Additionally, the EO exhibited anti-senescence potential and enhanced wound healing. Overall, this study highlights the remarkable pharmacological properties of Salvia aurea EO, which should be further explored in order to develop innovative, sustainable, and environmentally friendly skin products.

Chemical Profile, Anti-Microbial and Anti-Inflammaging Activities of Santolina rosmarinifolia L. Essential Oil from Portugal

Fungal infections and the accompanying inflammatory responses are associated with great morbidity and mortality due to the frequent relapses triggered by an increased resistance to antifungal agents. Furthermore, this inflammatory state can be exacerbated during inflammaging and cellular senescence. Essential oils (EO) are receiving increasing interest in the field of drug discovery due to their lipophilic nature and complex composition, making them suitable candidates in the development of new antifungal drugs and modulators of numerous molecular targets. This work chemically characterized the EO from Santolina rosmarinifolia L., collected in Setúbal (Portugal), and assessed its antifungal potential by determining its minimum inhibitory (MIC) and minimum lethal (MLC) concentration in accordance with the Clinical Laboratory Standard Guidelines (CLSI) guidelines, as well as its effect on several Candida albicans virulence factors. The anti-inflammatory effect was unveiled using lipopolysaccharide (LPS)-stimulated macrophages by assessing several pro-inflammatory mediators. The wound healing and anti-senescence potential of the EO was also disclosed. The EO was mainly characterized by β-pinene (29.6%), borneol (16.9%), myrcene (15.4%) and limonene (5.7%). It showed a strong antifungal effect against yeasts and filamentous fungi (MIC = 0.07-0.29 mg/mL). Furthermore, it inhibited dimorphic transition (MIC/16), decreased biofilm formation with a preeminent effect after 24 h (MIC/2) and disrupted preformed biofilms in C. albicans. Additionally, the EO decreased nitric oxide (NO) release (IC₅₀ = 0.52 mg/mL) and pro-IL-1β and inducible nitric oxide synthase (iNOS) expression in LPS-stimulated macrophages, promoted wound healing (91% vs. 81% closed wound) and reduced cellular senescence (53% vs. 73% β-galactosidase-positive cells). Overall, this study highlights the relevant pharmacological properties of S. rosmarinifolia, opening new avenues for its industrial exploitation.

Essential Oils in the Treatment of Various Types of Acne-A Review

Acne is a chronic, common disease that poses a significant therapeutic, psychological and social problem. The etiopathogenesis of this disease is not fully understood. Drugs used in general and external therapy should have anti-seborrhoeic, anticomadogenic, bactericidal, bacteriostatic, and anti-inflammatory properties. Acne treatment is often associated with the long-term use of antibiotics, contributing to the global antibiotic resistance crisis. In order to solve this problem, attention has been paid to essential oils and their terpene components with potent antimicrobial, anti-inflammatory, and antioxidant properties. Research shows that certain essential oils effectively reduce inflammatory acne lesions through mechanisms related to the sebaceous glands, colonization of Cutibacterium acnes, and reactive oxygen species (ROS). An example is tea tree oil (TTO), a more commonly used topical agent for treating acne. TTO has antimicrobial and anti-inflammatory activity. The paper presents the latest scientific information on the activity and potential use of specific essential oils in treating acne. Evidence of antibacterial, anti-inflammatory, and antioxidant activity of several essential oils and their main components was presented, indicating the possibility of using them in the treatment of acne.

Two-Phase Extraction Processes, Physicochemical Characteristics, and Autoxidation Inhibition of the Essential Oil Nanoemulsion of Citrus reticulata Blanco (Tangerine) Leaves

Combined ultrasound-microwave techniques and pre-enzymatic treatment (hemicellulase and cellulase) enhance essential oil isolation from Citrus reticulata Blanco (tangerine) leaves (CrBL). Subsequently, synergistic effects of modified amorphous octenyl succinic anhydride starch (OSA-MS), almond oil, and high-energy microfluidics were studied in synergy with ultrasound techniques in the production of CrBL essential oil (CrBL-EO) nanoemulsion (CrBL-EONE). GC-MS was used to study the extraction technique. Dynamic light scattering (DLS) analysis was used with confocal laser scanning microscopy (CLSM) techniques to investigate the nanoemulsion matrices' physical and chemical properties. The D-limonene nanoemulsion (D-LNE) reached the optimal size of droplets (65.3 ± 1.1 r.nm), polydispersity index (PDI) (0.167 ± 0.015), and ζ-potential (-41.0 ± 0.4 mV). Besides, the CrBL-EONE obtained the optimal size of droplets (86.5 ± 0.5 r.nm), PDI (0.182 ± 0.012), and ζ-potential (-40.4 ± 0.8 mV). All the nanoparticle treatments showed significant values in terms of the creaming index (CI%) and inhibition activity (IA%) in the β-carotene/linoleate system with a low degradation rate (DR). The current study's findings showed that integrated ultrasound-microwave techniques and pre-enzymatic treatment could enhance the extraction efficiency of the CrBL-EO. In addition, OSA-MS and almond oil can also be employed to produce CrBL-EONE and D-LNE.

Biobased polymer resources and essential oils: a green combination for antibacterial applications

To fight nosocomial infections, the excessive use of antibiotics has led to the emergence of multidrug-resistant microorganisms, which are now considered a relevant public health threat by the World Health Organization. To date, most antibacterial systems are based on the use of petro-sourced polymers, but the global supplies of these resources are depleting. Besides, silver NPs are widely accepted as the most active biocide against a wide range of bacterial strains but their toxicity is an issue. The growing interest in natural products has gained increasing interest in the last decade. Therefore, the design of functional antibacterial materials derived from biomass remains a significant challenge for the scientific community. Consequently, attention has shifted to naturally occurring substances such as essential oils (EOs), which are classified as Generally Recognized as Safe (GRAS). EOs can offer an alternative to the common antimicrobial agents as an inner solution or biocide agent to inhibit the resistance mechanism. Herein, this review not only aims at providing developments in the antibacterial modes of action of EOs against various bacterial strains and the recent advances in genomic and proteomic techniques for the elucidation of these mechanisms but also presents examples of biobased polymer resource-based EO materials and their antibacterial activities. Especially, we describe the antibacterial properties of biobased polymers, e.g. cellulose, starch, chitosan, PLA PHAs and proteins, associated with EOs (cinnamon (CEO), clove (CLEO), bergamot (BEO), ginger (GEO), lemongrass (LEO), caraway (CAEO), rosemary (REO), Eucalyptus globulus (EGEO), tea tree (TTEO), orange peel (OPEO) and apricot (Prunus armeniaca) kernel (AKEO) essential oils). Finally, we discuss the influence of EOs on the mechanical strength of bio-based materials.

Singular and Combined Effects of Essential Oil and Honey of Eucalyptus Globulus on Anti-Inflammatory, Antioxidant, Dermatoprotective, and Antimicrobial Properties: In Vitro and In Vivo Findings

Eucalyptus globulus is a plant widely used by the world population, including Morocco, in the treatment of several pathologies. The aim of this work is to evaluate the antioxidant, anti-inflammatory, dermatoprotective, and antimicrobial effects of essential oil and honey from E. globulus, as well as their combination. Chemical composition was determined by GC-MS analysis. The antioxidant activity was evaluated by three tests, namely, DPPH, reducing power, and the β-carotene/linoleic acid assay. The anti-inflammatory activity was investigated in vitro (5-lipoxygenase inhibition) and in vivo (carrageenan-induced paw edema model), while the dermatoprotective activity was tested in vitro (tyrosinase inhibition). Moreover, the antibacterial activity was assessed using agar well diffusion and microdilution methods. The results showed that eucalyptol presents the main compound of the essential oil of E. globulus (90.14%). The mixture of essential oil with honey showed the best antioxidant effects for all the tests used (0.07 < IC50 < 0.19 mg/mL), while the essential oil was the most active against tyrosinase (IC50 = 38.21 ± 0.13 μg/mL) and 5-lipoxygenase (IC50 = 0.88 ± 0.01 μg/mL), which corroborated the in vivo test. Additionally, the essential oil showed the best bactericidal effects against all strains tested, with inhibition diameter values ranging from 12.8 to 21.6 mm. The findings of this work showed that the combination of the essential oil with honey showed important results in terms of biological activity, but the determination of the underlying mechanisms of action remains a major prospect to be determined.

Forest Biomass as a Promising Source of Bioactive Essential Oil and Phenolic Compounds for Alzheimer's Disease Therapy

Alzheimer’s disease (AD) is the most common neurodegenerative disorder affecting elderly people worldwide. Currently, there are no effective treatments for AD able to prevent disease progression, highlighting the urgency of finding new therapeutic strategies to stop or delay this pathology. Several plants exhibit potential as source of safe and multi-target new therapeutic molecules for AD treatment. Meanwhile, Eucalyptus globulus extracts revealed important pharmacological activities, namely antioxidant and anti-inflammatory properties, which can contribute to the reported neuroprotective effects. This review summarizes the chemical composition of essential oil (EO) and phenolic extracts obtained from Eucalyptus globulus leaves, disclosing major compounds and their effects on AD-relevant pathological features, including deposition of amyloid-β (Aβ) in senile plaques and hyperphosphorylated tau in neurofibrillary tangles (NFTs), abnormalities in GABAergic, cholinergic and glutamatergic neurotransmission, inflammation, and oxidative stress. In general, 1,8-cineole is the major compound identified in EO, and ellagic acid, quercetin, and rutin were described as main compounds in phenolic extracts from Eucalyptus globulus leaves. EO and phenolic extracts, and especially their major compounds, were found to prevent several pathological cellular processes and to improve cognitive function in AD animal models. Therefore, Eucalyptus globulus leaves are a relevant source of biological active and safe molecules that could be used as raw material for nutraceuticals and plant-based medicinal products useful for AD prevention and treatment.

Essential Oil from Eucalyptus globulus (Labill.) Activates Complement Receptor-Mediated Phagocytosis and Stimulates Podosome Formation in Human Monocyte-Derived Macrophages

Eucalyptus essential oil and its major constituent eucalyptol are extensively employed in the cosmetic, food, and pharmaceutical industries and their clinical use has recently expanded worldwide as an adjuvant in the treatment of infective and inflammatory diseases. We previously demonstrated that essential oil from Eucalyptus globulus (Labill.) (EO) stimulates in vitro the phagocytic activity of human monocyte-derived macrophages and counteracts the myelotoxicity induced by the chemotherapeutic 5-fluorouracil in immunocompetent rats. Here we characterize some mechanistic aspects underlying the immunostimulatory ability exerted by EO on macrophages. The internalization of fluorescent beads, fluorescent zymosan BioParticles, or apoptotic cancer cells was evaluated by confocal microscopy. Pro-inflammatory cytokine and chemokine release was determined by flow cytometry using the BD cytometric bead array. Receptor involvement in EO-stimulated phagocytosis was assessed using complement- or IgG-opsonized zymosan particles. The localization and expression of podosome components was analyzed by confocal microscopy and western blot. The main results demonstrated that: EO-induced activation of a macrophage is ascribable to its major component eucalyptol, as recently demonstrated for other cells of innate immunity; EO implements pathogen internalization and clearance by stimulating the complement receptor-mediated phagocytosis; EO stimulates podosome formation and increases the expression of podosome components. These results confirm that EO extract is a potent activator of innate cell-mediated immunity and thereby increase the scientific evidence supporting an additional property of this plant extract besides the known antiseptic and anti-inflammatory properties.