Essential oil components and cytochrome P450 enzymes: a review

Effect of Essential Oil Components on the Activity of Steroidogenic Cytochrome P450

Endocrine-disrupting chemicals (EDCs) may impact the development of prostate cancer (PCa) by altering the steroid metabolism. Although their exact mechanism of action in controlling tumor growth is not known, EDCs may inhibit steroidogenic enzymes such as CYP17A1 or CYP19A1 which are involved in the production of androgens or estrogens. High levels of circulating androgens are linked to PCa in men and Polycystic Ovary Syndrome (PCOS) in women. Essential oils or their metabolites, like lavender oil and tea tree oil, have been reported to act as potential EDCs and contribute towards sex steroid imbalance in cases of prepubertal gynecomastia in boys and premature thelarche in girls due to the exposure to lavender-based fragrances. We screened a range of EO components to determine their effects on CYP17A1 and CYP19A1. Computational docking was performed to predict the binding of essential oils with CYP17A1 and CYP19A1. Functional assays were performed using the radiolabeled substrates or Liquid Chromatography-High-Resolution Mass Spectrometry and cell viability assays were carried out in LNCaP cells. Many of the tested compounds bind close to the active site of CYP17A1, and (+)-Cedrol had the best binding with CYP17A1 and CYP19A1. Eucalyptol, Dihydro-β-Ionone, and (-)-α-pinene showed 20% to 40% inhibition of dehydroepiandrosterone production; and some compounds also effected CYP19A1. Extensive use of these essential oils in various beauty and hygiene products is common, but only limited knowledge about their potential detrimental side effects exists. Our results suggest that prolonged exposure to some of these essential oils may result in steroid imbalances. On the other hand, due to their effect on lowering androgen output and ability to bind at the active site of steroidogenic cytochrome P450s, these compounds may provide design ideas for novel compounds against hyperandrogenic disorders such as PCa and PCOS.

Essential oils and their nanoformulations for breast cancer therapy

Breast Cancer (BC) is the most prevalent type of cancer in the world. Current treatments include surgery, radiation, and chemotherapy but often are associated with high toxicity to normal tissues, chemoresistance, and relapse. Thus, developing novel therapies which could combat these limitations is essential for effective treatment. In this context, phytochemicals are increasingly getting popular due to their safety profile, ability to efficiently target tumors, and circumvent limitations of existing treatments. Essential Oils (EOs) are mixtures of various phytochemicals which have shown potential anticancer activity in preclinical BC models. However, their clinical translation is limited by factors such as high volatility, low stability, and poor solubility. Nanotechnology has facilitated their encapsulation in a variety of nanostructures and proven to overcome these limitations. In this review, we have efficiently summarized the current knowledge on the anticancer effect of EOs and constituents in both in in vitro and in in vivo BC models. Further, we also provide a descriptive account on the potential of nanotechnology in enhancing the anti-BC activity of EOs and their constituents. The papers discussed in this review were selected using the keywords "antiproliferative Essential Oils in breast cancer," "anticancer activity of Essential Oil in breast cancer," and "cytotoxicity of Essential Oils in breast cancer" performed in PubMed and ScienceDirect databases.

A Comparative GC/MS Analysis of Citrus Essential Oils: Unveiling the Potential Benefits of Herb-Drug Interactions in Preventing Paracetamol-Induced Hepatotoxicity

Our study aimed to test the potential of Citrus oils in protecting against paracetamol (PAR)-induced hepatotoxicity. The essential oils of Pineapple sweet orange (OO), Murcott mandarin (MO), Red grapefruit (GO), and Oval kumquat (KO) were investigated using gas chromatography coupled with mass spectrometry (GC/MS). Twenty-seven compounds were identified, with monoterpene hydrocarbons being abundant class. d-Limonene had the highest percentage (92.98 %, 92.82 %, 89.75 %, and 94.46 % in OO, MO, GO, and KO, respectively). Hierarchical cluster analysis (HCA) and principal components analysis (PCA) revealed that octanal, linalool, germacrene D, and d-limonene were the principal discriminatory metabolites that segregated the samples into three distinct clusters. In vitro antioxidant capacities were ranged from 1.2-12.27, 1.79-5.91, and 235.05-585.28 μM Trolox eq/mg oil for 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic (ABTS), ferric-reducing antioxidant power (FRAP), and oxygen radical absorbance capacity (ORAC), respectively. In vivo, citrus oils exhibited a significant reduction in alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), and nitric oxide (NO). Additionally, there was an increase in glutathione reductase (GSH), and the liver architecture was nearly normal. Molecular docking revealed that d-limonene exhibited a good inhibitory interaction with cytochrome P450 (CYP450) isoforms 1A2, 3A4, and 2E1, with binding energies of -6.17, -4.51, and -5.61 kcal/mol, respectively.

Predictions of the Biological Effects of Several Acyclic Monoterpenes as Chemical Constituents of Essential Oils Extracted from Plants

Acyclic terpenes are biologically active natural products having applicability in medicine, pharmacy, cosmetics and other practices. Consequently, humans are exposed to these chemicals, and it is necessary to assess their pharmacokinetics profiles and possible toxicity. The present study considers a computational approach to predict both the biological and toxicological effects of nine acyclic monoterpenes: beta-myrcene, beta-ocimene, citronellal, citrolellol, citronellyl acetate, geranial, geraniol, linalool and linalyl acetate. The outcomes of the study emphasize that the investigated compounds are usually safe for humans, they do not lead to hepatotoxicity, cardiotoxicity, mutagenicity, carcinogenicity and endocrine disruption, and usually do not have an inhibitory potential against the cytochromes involved in the metabolism of xenobiotics, excepting CYP2B6. The inhibition of CYP2B6 should be further analyzed as this enzyme is involved in both the metabolism of several common drugs and in the activation of some procarcinogens. Skin and eye irritation, toxicity through respiration and skin-sensitization potential are the possible harmful effects revealed by the investigated compounds. These outcomes underline the necessity of in vivo studies regarding the pharmacokinetics and toxicological properties of acyclic monoterpenes so as to better establish the clinical relevance of their use.

Artemisia extracts differ from artemisinin effects on human hepatic CYP450s 2B6 and 3A4 in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

The Chinese medicinal herb, Artemisia annua L., has been used for >2,000 yr as traditional tea infusions to treat a variety of infectious diseases including malaria, and its use is spreading globally (along with A. afra Jacq. ex Willd.) mainly through grassroots efforts.

AIM OF THE STUDY

Artemisinin is more bioavailable delivered from the plant, Artemisia annua L. than the pure drug, but little is known about how delivery via a hot water infusion (tea) alters induction of hepatic CYP2B6 and CYP3A4 that metabolize artemisinin.

MATERIALS AND METHODS

HepaRG cells were treated with 10 μM artemisinin or rifampicin (positive control), and teas (10 g/L) of A. annua SAM, and A. afra SEN and MAL with 1.6, 0.05 and 0 mg/g DW artemisinin in the leaves, respectively; qPCR and Western blots were used to measure CYP2B6 and CYP3A4 responses. Enzymatic activity of these P450s was measured using human liver microsomes and P450-Glo assays.

RESULTS

All teas inhibited activity of CYP2B6 and CYP3A4. Artemisinin and the high artemisinin-containing tea infusion (SAM) induced CYP2B6 and CYP3A4 transcription, but artemisinin-deficient teas, MAL and SEN, did not. Artemisinin increased CYP2B6 and CYP3A4 protein levels, but none of the three teas did, indicating a post-transcription inhibition by all three teas.

CONCLUSIONS

This study showed that Artemisia teas inhibit activity and artemisinin autoinduction of CYP2B6 and CYP3A4 post transcription, a response likely the effect of other phytochemicals in these teas. Results are important for understanding Artemisia tea posology.

Natural Compounds in the Battle against Microorganisms-Linalool

The purpose of this article is to present recent studies on the antimicrobial properties of linalool, the mechanism of action on cells and detoxification processes. The current trend of employing compounds present in essential oils to support antibiotic therapy is becoming increasingly popular. Naturally occurring monoterpene constituents of essential oils are undergoing detailed studies to understand their detailed effects on the human body, both independently and in doses correlated with currently used pharmaceuticals. One such compound is linalool, which is commonly found in many herbs and is used to flavor black tea. This compound is an excellent fragrance additive for cosmetics, enhancing the preservative effect of the formulations used in them or acting as an anti-inflammatory on mild skin lesions. Previous studies have shown that it is extremely important due to its broad spectrum of biological activities, i.e., antioxidant, anti-inflammatory, anticancer, cardioprotective and antimicrobial. Among opportunistic hospital strains, it is most active against Gram-negative bacteria. The mechanism of action of linalool against microorganisms is still under intensive investigation. One of the key aspects of linalool research is biotransformation, through which its susceptibility to detoxification processes is determined.

Essential Oils as Multicomponent Mixtures and Their Potential for Human Health and Well-Being

Essential oils (EOs) and their individual volatile organic constituents have been an inherent part of our civilization for thousands of years. They are widely used as fragrances in perfumes and cosmetics and contribute to a healthy diet, but also act as active ingredients of pharmaceutical products. Their antibacterial, antiviral, and anti-inflammatory properties have qualified EOs early on for both, the causal and symptomatic therapy of a number of diseases, but also for prevention. Obtained from natural, mostly plant materials, EOs constitute a typical example of a multicomponent mixture (more than one constituent substances, MOCS) with up to several hundreds of individual compounds, which in a sophisticated composition make up the property of a particular complete EO. The integrative use of EOs as MOCS will play a major role in human and veterinary medicine now and in the future and is already widely used in some cases, e.g., in aromatherapy for the treatment of psychosomatic complaints, for inhalation in the treatment of respiratory diseases, or topically administered to manage adverse skin diseases. The diversity of molecules with different functionalities exhibits a broad range of multiple physical and chemical properties, which are the base of their multi-target activity as opposed to single isolated compounds. Whether and how such a broad-spectrum effect is reflected in natural mixtures and which kind of pharmacological potential they provide will be considered in the context of ONE Health in more detail in this review.

Odorant Metabolism in Humans

Odorants are relatively small molecules which are easily taken up and distributed in the human body. Despite their relevance in everyday life, however, only a limited amount of evidence about their metabolism, pathways, and bioactivities in the human body exists. With this Review, we aim to encourage future interdisciplinary research on the function and mechanisms of the biotransformation of odorants, involving different disciplines such as nutrition, medicine, biochemistry, chemistry, and sensory sciences. Starting with a general overview of the different ways of odorant uptake and enzymes involved in the metabolism of odorants, a more precise description of biotransformation processes and their function in the oral cavity, the nose, the lower respiratory tract (LRT), and the gastrointestinal tract (GIT) is given together with an overview of the different routes of odorant excretion. Finally, perspectives for future research are discussed.

Preliminary studies on the effect of simulated digestion on the antioxidant activity of monoterpenes

One of several possible ways of predicting substance bioactivity under in vivo conditions is through simulated studies based on conditions comparable to those within the organism. Having regards to pH and digestive enzymes, such an approach is through simulated digestion. Simulated studies allow gaining an understanding of physiological conditions and a prediction of compound behavior. The presented studies are based on simulated digestion (SD) to which selected monoterpenes (γ-terpinene, α-terpinene, α-phellandrene, carvone, menthone, isopulegol, α-pinene, β-pinene, terpinene-4-ol, linalool, eucalyptol, p-cymene, citral, citronellal) have been subjected. The procedure included changes pH (2.0 and 8.5) and digestive enzymes (pepsine in gastric stage and pancreatin in duodenal stage) to better understand what goes on within the gastro-intestinal tract. The changes were observed for gastric and duodenal stages, as well as for two phases: oil and water. Obtained results revealed both positive and negative influence of gastrointestinal conditions on monoterpenes antioxidant activity. However, positive impact prevailed (γ-terpinene, citral, eucalyptol, isopulegol, α-pinene). The differentiation in activity can be explained by solubility in oil/water phases and the biotransformation of studied compounds.

Essential oils as anticancer agents: Potential role in malignancies, drug delivery mechanisms, and immune system enhancement

Cancer retains a central place in fatality rates among the wide variety of diseases known world over, and the conventional synthetic medicaments, albeit used until now, produce numerous side effects. As a result, newer, better, and safer alternatives such as natural plant products, are gravely required. Essential oils (EOs) offer a plethora of bioactivities including antibacterial, antiviral, antioxidant, and anticancer properties, therefore, the use of EOs in combination with synthetic drugs or aromatherapy continues to be popular in many settings. In view of the paramount importance of EOs and their potential bioactivities, this review summarizes the current knowledge on the interconnection between EOs and cancer treatment. In particular, the current review presents an updated summary of the chemical composition of EOs, their current applications in cancer treatments based on clinical studies, and the mechanism of action against the cancer cell lines. Similarly, an overview of using EOs in aromatherapy and enhancing immunity during cancer treatment is provided. Further, this review focuses on the recent technological advancements such as the loading of EOs using protein microspheres, ligands, or nanoemulsions/nanoencapsulation, which offer multiple benefits in cancer treatment via site-specific and target-oriented delivery of drugs. The continuing clinical studies of EOs implicate that their pharmacological applications are a rewarding research area.

Fumigant toxicity and biochemical effects of selected essential oils toward the red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae)

Tribolium castaneum Herbst (Coleoptera: Tenebrionidae) is an insect popularly known as the red flour beetle, it is widely distributed worldwide and can cause serious damage to stored grains. Chemical control is the most used method for managing this pest, however, some substances are toxic to mammals and the environment. Therefore, the development of new effective and safe insecticides is necessary. Essential oils (EOs) can be considered as a potential alternative in the development of pesticides due to their physicochemical properties and varied effects against insects. In the current study, was determined the fumigant toxicity and biochemical effects of selected essential oils against T. castaneum. The 23 selected EOs were characterized by GC-MS and their fumigant lethal concentrations were determined. An exploratory Cluster analysis was performed to find a relationship between fumigant toxicity and chemical composition. Finally, the inhibition of the catalytic activity of acetylcholinesterase (AChE), glutathione S-transferase (GST) and catalase (CAT) was evaluated using protein homogenates obtained from T. castaneum. The results indicated that EOs with the highest fumigant potential were those with greater diversity in their composition, while the least active EOs presented mainly monoterpenes. The most active EOs were those obtained from Foeniculum vulgare and Zanthoxylum monophyllum with LC₅₀ values of 16.23 and 18.54 μL/L air respectively. Regarding the inhibition of the enzymatic activity of the 23 EOs evaluated at 500 μL/L, only two caused an inhibition greater that 50% on AChE, which corresponded to EOs from Piper nigrum and Rosmarinus officinalis. Likewise, EOs from C. sinensis, Piper aduncum and Zanthoxylum monophyllum were the only ones able to inhibiting GST activity by more than 50%. Respecting CAT inhibition, 7 EOs caused and inhibition greater than 50%, highlighting those from Lavandula angustifolia, C. sempervirens and Eucalyptus sp. These results show that the EOs evaluated in this study seems to be a promising bio-controller of T. castaneum since have high fumigant toxicity and exert different mechanisms of action.

Pharmacology of Natural Volatiles and Essential Oils in Food, Therapy, and Disease Prophylaxis

This commentary critically examines the modern paradigm of natural volatiles in 'medical aromatherapy', first by explaining the semantics of natural volatiles in health, then by addressing chemophenetic challenges to authenticity or reproducibility, and finally by elaborating on pharmacokinetic and pharmacodynamic processes in food, therapy, and disease prophylaxis. Research over the last 50 years has generated substantial knowledge of the chemical diversity of volatiles, and their strengths and weaknesses as antimicrobial agents. However, due to modest in vitro outcomes, the emphasis has shifted toward the ability to synergise or potentiate non-volatile natural or pharmaceutical drugs, and to modulate gene expression by binding to the lipophilic domain of mammalian cell receptors. Because essential oils and natural volatiles are small and lipophilic, they demonstrate high skin penetrating abilities when suitably encapsulated, or if derived from a dietary item they bioaccumulate in fatty tissues in the body. In the skin or body, they may synergise or drive de novo therapeutic outcomes that range from anti-inflammatory effects through to insulin sensitisation, dermal rejuvenation, keratinocyte migration, upregulation of hair follicle bulb stem cells or complementation of anti-cancer therapies. Taking all this into consideration, volatile organic compounds should be examined as candidates for prophylaxis of cardiovascular disease. Considering the modern understanding of biology, the science of natural volatiles may need to be revisited in the context of health and nutrition.

Human absorption of monoterpenes after a 2-h forest exposure: A field experiment in a Mediterranean holm oak forest

The current body of literature points monoterpenes as one of the determinant factors of the interaction between forests and human health. The present study aims at analyzing the monoterpene absorption by humans during a 2 -hs forest exposure in a Mediterranean holm oak forest focusing on the four most abundant monoterpene compounds: alpha-pinene, beta-pinene, alpha-phellandrene and limonene. Participants' blood samples were collected before and after exposure to forest or urban environment (control). We conducted air and blood sampling using cartridges and head space method and determined the monoterpene compounds through CGMS. We identified the four compounds in forest air during the experimental study being alpha-pinene the monoterpene with the greatest concentration. Results show no significant changes in monoterpene blood concentrations for the forest and control group. However, a negative significant relationship between absorption and baseline blood concentration of the most abundant forest air monoterpenes, alpha-pinene and beta-pinene, was found in individuals visiting the forest, i.e. higher absorption was found the lower the baseline blood concentration was. Although no significant lineal correlation could be spotted between the vital variables and the monoterpene absorption, we found significant correlations between the absorption of the monoterpene compounds. This attempt, first in a Mediterranean holm oak forest, can serve as a starting point and constitute a valuable contribution for further research in regard to experimental design and laboratory analysis.

Insecticidal Activity of Commiphora erythraea Essential Oil and Its Emulsions Against Larvae of Three Mosquito Species

The use of essential oils as ecofriendly tools for vector management is one of the mainstreams for biopesticide research. We evaluated the larvicidal properties of Commiphora erythraea (opoponax) essential oil and its fractions against Culex restuans Theobald, Culex pipiens L., and Aedes aegypti L. The use of bio-based amylose-N-1-hexadecylammonium chloride inclusion complex (Hex-Am) and amylose-sodium palmitate inclusion complex (Na-Palm) as emulsifiers for C. erythraea essential oil was also investigated. Bisabolene was the most abundant chemical constituent in the whole essential oil (33.9%), fraction 2 (62.5%), and fraction 4 (23.8%) while curzerene (32.6%) and α-santalene (30.1%) were the dominant chemical constituents in fractions 1 and 3, respectively. LC50 values for the whole essential oil were 19.05 ppm for Cx. restuans, 22.61 ppm for Cx. pipiens, and 29.83 ppm for Ae. aegypti and differed significantly. None of the four C. erythraea essential oil fractions were active against mosquito larvae. Two CYP450 genes (CYP6M11 and CYP6N12) and one GST gene (GST-2) were significantly upregulated in Ae. aegypti larvae exposed to C. erythraea essential oil suggesting their potential involvement in metabolic pathways for C. erythraea essential oil. Essential oil emulsions produced with Hex-Am were more toxic than the whole essential oil while those produced with Na-Palm had similar toxicity as the whole essential oil. These findings demonstrate that C. erythraea essential oil is a promising source of mosquito larvicide and that the use of Hex-Am as an emulsifier can enhance the insecticidal properties of C. erythraea essential oil.

One Hundred Faces of Geraniol

Geraniol is a monoterpenic alcohol with a pleasant rose-like aroma, known as an important ingredient in many essential oils, and is used commercially as a fragrance compound in cosmetic and household products. However, geraniol has a number of biological activities, such as antioxidant and anti-inflammatory properties. In addition, numerous in vitro and in vivo studies have shown the activity of geraniol against prostate, bowel, liver, kidney and skin cancer. It can induce apoptosis and increase the expression of proapoptotic proteins. The synergy of this with other drugs may further increase the range of chemotherapeutic agents. The antibacterial activity of this compound was also observed on respiratory pathogens, skin and food-derived strains. This review discusses some of the most important uses of geraniol.

Effects of maternal T-2 toxin exposure on the hepatic glycolipid metabolism in young mice

T-2 toxin is a kind of group A trichothecenes mycotoxins, frequently detected in various foods and feeds, having high toxic effects on both humans and animals. The present study aims to investigate the toxic effects of T-2 toxin exposure to ICR mice during pregnancy and lactation on liver glycolipid metabolism of young mice. The pregnant mice were given 0, 0.005 and 0.05 mg of T-2 toxin/kg bw daily through oral gavage from late gestation (GD 14) to the lactation (LD 21). Liver and serum samples of the young mice were collected on postnatal day 21 (PND 21), PND 28 and PND 56. The results showed that T-2 toxin increased the contents of triglycerides (TG), total cholesterol (T-CHO) and glucose in serum of young mice on PND 21 and PND 28. In addition, obvious lipid droplets of liver in T-2 toxin treatment groups were observed, especially in 0.05 mg group of PND 21and PND 28. Compared with the control group, T-2 treatment also increased the expressions of genes associated with liver glycolipid metabolism, such as PEPCK, Glut2, Fas, Acox1, Hmgcr, PPARα, Srebp1 and CD36. These results demonstrated T-2 toxin exposure to pregnant mice could cause liver glycolipid metabolism disruption in the young mice and the toxic effects weakened on PND 56.