Percutaneous absorption of the montoterpene carvone: implication of stereoselective metabolism on blood levels

Monoterpenoid aryl hydrocarbon receptor allosteric antagonists protect against ultraviolet skin damage in female mice

The human aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that is a pivotal regulator of human physiology and pathophysiology. Allosteric inhibition of AhR was previously thought to be untenable. Here, we identify carvones as noncompetitive, insurmountable antagonists of AhR and characterize the structural and functional consequences of their binding. Carvones do not displace radiolabeled ligands from binding to AhR but instead bind allosterically within the bHLH/PAS-A region of AhR. Carvones do not influence the translocation of ligand-activated AhR into the nucleus but inhibit the heterodimerization of AhR with its canonical partner ARNT and subsequent binding of AhR to the promoter of CYP1A1. As a proof of concept, we demonstrate physiologically relevant Ahr-antagonism by carvones in vivo in female mice. These substances establish the molecular basis for selective targeting of AhR regardless of the type of ligand(s) present and provide opportunities for the treatment of disease processes modified by AhR.

Carvone and its pharmacological activities: A systematic review

Natural products from plants have gained prominence in the search for therapeutic alternatives. Monoterpenes, such as carvone, are suggested as candidates for the treatment of several diseases. Therefore, the objective of this study is to review the pharmacological activities of carvone in experimental models in vitro and in vivo. For this, the searches were carried out in May 2020 (upgraded in July 2021) in the databases of PubMed, Web of Science and Scopus and gathered studies on the pharmacological activities of carvone. Two independent reviewers performed the selection of articles using the Rayyan application, extracted the relevant data and assessed the methodological quality of the selected studies using Syrcle's risk of bias tool. Ninety-one articles were selected that described 10 pharmacological activities of carvone, such as antimicrobial, antispasmodic, anti-inflammatory, antioxidant, antinociceptive, anticonvulsant, among others. The evaluation of the methodological quality presented an uncertain risk of bias for most studies. In light of that, carvone stands out as a viable and promising alternative in the treatment of several pathological conditions. However, carrying out studies to evaluate possible mechanisms of action and the safety of this monoterpene is recommended.

Bioactive properties of the aromatic molecules of spearmint (Mentha spicata L.) essential oil: a review

Spearmint belongs to the genus Mentha in the family Labiateae (Lamiaceae), which is wildly cultivated worldwide for its remarkable aroma and commercial value. The aromatic molecules of spearmint essential oil,...

(-)-cis-Carveol, a Natural Compound, Improves β-Amyloid-Peptide 1-42-Induced Memory Impairment and Oxidative Stress in the Rat Hippocampus

Alzheimer's disease (AD) could be considered a multifactorial neurodegenerative disorder characterized by the accumulation of the β-amyloid-peptide (Aβ) within the brain leading to cognitive deficits, oxidative stress, and neuroinflammation. The present work was carried out to investigate the neuroprotective effect of (-)-cis-carveol (1% and 3%, for 21 days) against the β-amyloid-peptide 1-42- (Aβ1-42-) induced AD. Twenty-five rats were divided into five groups (n = 5/group): the first group-control (sham-operated); the second group-Aβ1-42 (1 mM) that received donepezil treatment (5 mg/kg, as the positive reference drug in the Y-maze and the radial arm maze tests); the third group-Aβ1-42 (1 mM); the fourth and fifth groups-Aβ1-42 (1 mM) that received (-)-cis-carveol treatment groups (1% and 3%). The results of this study demonstrated that (-)-cis-carveol improved Aβ1-42-induced memory deficits examined by using Y-maze and radial arm maze in vivo tests. Also, the biochemical analyses of the hippocampus homogenates showed that (-)-cis-carveol reduced hippocampal oxidative stress caused by Aβ1-42. Our results suggested that the use of (-)-cis-carveol may be suitable for decreasing AD-related symptoms.

Novel cuminaldehyde self-emulsified nanoemulsion for enhanced antihepatotoxicity in carbon tetrachloride-treated mice

Objectives

Cuminaldehyde self-emulsified nanoemulsion (CuA-SEN) was prepared and optimised to improve its oral bioavailability and antihepatotoxicity.

Methods

Cuminaldehyde self-emulsified nanoemulsion was developed through the self-nanoemulsification method using Box–Behnken Design (BBD) tool while appropriate physicochemical indices were evaluated. The optimised CuA-SEN was characterised via droplet size (DS), morphology, polydispersity index (PDI), zeta potential (ZP), entrapment efficiency, in-vitro release, and pharmacokinetic studies while its antihepatotoxicity was evaluated.

Key findings

Cuminaldehyde self-emulsified nanoemulsion with acceptable characteristics (mean DS-48.83 ± 1.06 nm; PDI-0.232 ± 0.140; ZP-29.92 ± 1.66 mV; EE-91.51 ± 0.44%; and drug-loading capacity (DL)-9.77 ± 0.75%) was formulated. In-vitro drug release of CuA-SEN significantly increased with an oral relative bioavailability of 171.02%. Oral administration of CuA-SEN to CCl4-induced hepatotoxicity mice markedly increased the levels of superoxide dismutase, glutathione and catalase in serum. Also, CuA-SEN reduced the levels of tumour necrosis factor-alpha and interleukin-6 in both serum and liver tissues while aspartate aminotransferase, alanine aminotransferase and malonaldehyde levels were significantly decreased.

Conclusions

These findings showed that the improved bioavailability of cuminaldehyde via SEN provided an effective approach for enhancing antioxidation, anti-inflammation and antihepatotoxicity of the drug.

Les huiles essentielles comme agents anticancéreux : actualité sur le mode d’action

Le cancer est une maladie complexe qui présente un réel problème de santé publique à travers le monde et cause statiquement sept millions de décès chaque année. Au cours des dernières décennies, la thérapie anticancéreuse a connu un réel bouleversement et un foisonnement de découvertes fondamentales. Plusieurs études accumulatives ont révélé l’activité antitumorale des substances naturelles isolées à partir de plantes. Les huiles essentielles (HE) et leurs constituants ont montré des activités anticancéreuses puissantes in vitro et in vivo. Cependant, les mécanismes d’action sont encore peu étudiés et moins connus. Par ailleurs, leur application dans l’industrie pharmaceutique nécessite une spécificité– sélectivité pharmacodynamique absolue. Dans le présent travail, nous présentons une synthèse des travaux réalisés sur les mécanismes d’actions anticancéreuses des HE et leurs composés bioactifs.

The safety evaluation of food flavouring substances: the role of metabolic studies

The safety assessment of a flavour substance examines several factors, including metabolic and physiological disposition data. The present article provides an overview of the metabolism and disposition of flavour substances by identifying general applicable principles of metabolism to illustrate how information on metabolic fate is taken into account in their safety evaluation. The metabolism of the majority of flavour substances involves a series both of enzymatic and non-enzymatic biotransformation that often results in products that are more hydrophilic and more readily excretable than their precursors. Flavours can undergo metabolic reactions, such as oxidation, reduction, or hydrolysis that alter a functional group relative to the parent compound. The altered functional group may serve as a reaction site for a subsequent metabolic transformation. Metabolic intermediates undergo conjugation with an endogenous agent such as glucuronic acid, sulphate, glutathione, amino acids, or acetate. Such conjugates are typically readily excreted through the kidneys and liver. This paper summarizes the types of metabolic reactions that have been documented for flavour substances that are added to the human food chain, the methodologies available for metabolic studies, and the factors that affect the metabolic fate of a flavour substance.

In vitro anti-MRSA activity of carvone with gentamicin

Carvone is one of the naturally occurring monoterpenes, the largest class of secondary metabolites in plants, and exists in two enantiomers, R-carvone (R-car) and S-car. The objective of this study was to investigate the antimicrobial activity of R-car and S-car with gentamicin (GET) against methicillin-resistant Staphylococcus aureus (MRSA). MRSA is a major human pathogen that causes serious problems, including hospital-acquired pneumonia, abscesses and surgical wound infections. Nosocomial MRSA infections often exhibit multidrug resistance. In the present study, antimicrobial susceptibility testing was performed with R-car, S-car and GET using the broth microdilution method. Minimal inhibitory concentration values for R- and S-car against six different strains of S. aureus ranged between 500 and 1,000 μg/ml. Anti-MRSA activity was evaluated using the checkerboard and time-kill assays to investigate the potential synergistic effects of different combinations of the carvone enantiomers and GET. R-car plus S-car, R-car plus GET and S-car plus GET exhibited significant synergistic activity against MRSA. These findings suggest that the single-agent anti-MRSA activities of R-car, S-car and GET are effectively increased through combination therapy. This study showed that carvone may be a potential adjuvant antimicrobial agent.

Comparison of Liquid-Liquid Partition, HS-SPME and Static HS GC/MS Analysis for the Quantification of (–)-Linalool in Human Whole Blood Samples

The aim of this investigation was to develop a fast and convenient method for the determination of (–)-linalool in human whole blood to facilitate pharmacokinetic studies. Analytical protocols were elaborated for three different GC/MS sampling techniques, i.e., static headspace ( S-HS), headspace solid phase micro extraction (HS-SPME), and liquid-liquid partition. In principle, all tested methods were feasible, but s-HS had the greatest benefit because of the easy handling of the blood samples and its short analysis time. For s-HS two different incubation temperatures were tested (40°C and 60°C). The limit of detection was slightly lower when samples were incubated at 60°C, but the same quantitative results were achieved using α–terpineol as internal standard. An accurate and sensitive method for the quantification of (–)-linalool in blood samples after either inhalation or percutaneous application, as well as pharmacokinetic data are presented.

Relaxing effect of ylang ylang oil on humans after transdermal absorption

The aim of this study was to investigate the effects of ylang ylang oil (Cananga odorata, Annonaceae) on human physiological parameters and self-evaluation after transdermal absorption. Forty healthy volunteers participated in the experiments. Physiological parameters recorded were skin temperature, pulse rate, breathing rate and blood pressure. Self-evaluation was assessed by means of visual analog scales (VAS). The ylang ylang oil caused a significant decrease of blood pressure and a significant increase of skin temperature. At the behavioral level, subjects in the ylang ylang oil group rated themselves more calm and more relaxed than subjects in the control group. These findings are likely to represent a relaxing effect of the ylang ylang oil and provide some evidence for the usage of the ylang ylang oil in aromatherapy such as causing a relief of depression and stress in humans.

Sedative effects of the jasmine tea odor and (R)-(-)-linalool, one of its major odor components, on autonomic nerve activity and mood states

We investigated the effects of the odor of jasmine tea on autonomic nerve activity and mood states in a total of 24 healthy volunteers. We used the odor of jasmine tea at the lowest concentration that could be detected by each subject but that did not elicit any psychological effects. R-R intervals and the POMS test were measured before and after inhalation of the odors for 5 min. Both jasmine tea and lavender odors at perceived similar intensity caused significant decreases in heart rate and significant increases in spectral integrated values at high-frequency component in comparison with the control (P < 0.05). In the POMS tests, these odors produced calm and vigorous mood states. We also examined the effects of (R)-(-)-linalool, one of its major odor components, at the same concentration as in the tea, and (S)-(+)-linalool. Only (R)-(-)-linalool elicited a significant decrease in heart rate (P < 0.05) and an increase in high-frequency component in comparison with the controls, and produced calm and vigorous mood states. Thus, the low intensity of jasmine tea odor has sedative effects on both autonomic nerve activity and mood states, and (R)-(-)-linalool, one of its components, can mimic these effects.

Aromatherapy practice in nursing: literature review

BACKGROUND

The use of aromatherapy in nursing care continues to be popular in many settings. Most of the nursing literature relates to the use of essential oils in low doses for massage or use of the oils as environmental fragrances. Information from the wider literature may add to the evidence base for use of this therapy in nursing.

AIM

This paper reports a literature relating to the use of aromatherapy by nurses and critically evaluates the evidence to support this practice.

METHOD

Medline, CINAHL, MANTIS and EBSCO Host databases were searched for papers related to use of essential oils and/or aromatherapy. Papers were also obtained through cross-checking of reference lists. A total of 165 articles have been included in this review. Nursing papers were published since 1990 were included, but some references from 1971 onwards relating to scientific research conducted on essential oils were also included. These remain valuable as they are probably the only reference available for a specific oil or property, or show the development of knowledge in this area. Papers were excluded if they consisted only of brief case studies presented in abstract form. The review covers key professional issues and the principal areas of clinical practice where aromatherapy is used.

FINDINGS

Despite calls for more research in the 1980s and 1990s, there is still little empirical evidence to support the use of aromatherapy in nursing practice beyond enhancing relaxation. Its popularity needs to be balanced against the potential risks related to allergies, safety and inappropriate use by inexperienced users.

CONCLUSIONS

There is great potential for more collaborative research by nurses to explore the clinical applications in greater detail and to move beyond the low dose paradigm of application of essential oils.