Chemical Composition and Antioxidant Activity of the Essential Oils of Citral-Rich Chemotype Cinnamomum camphora and Cinnamomum bodinieri

Identification of key genes controlling monoterpene biosynthesis of Citral-type Cinnamomum bodinieri Levl. Based on transcriptome and metabolite profiling

The citral-type is the most common chemotype in Cinnamomum bodinieri Levl (C. bodinieri), which has been widely used in the daily necessities, cosmetics, biomedicine, and aromatic areas due to their high citral content. Despite of this economic prospect, the possible gene-regulatory roles of citral biosynthesis in the same geographic environment remains unknown. In this study, the essential oils (EOs) of three citral type (B1, B2, B3) and one non-citral type (B0) varieties of C. bodinieri were identified by GC-MS after hydrodistillation extraction in July. 43 components more than 0.10% were identified in the EOs, mainly composed of monoterpenes (75.8-91.84%), and high content citral (80.63-86.33%) were identified in citral-type. Combined transcriptome and metabolite profiling analysis, plant-pathogen interaction(ko04626), MAPK signaling pathway-plant(ko04016), starch and sucrose metabolism(ko00500), plant hormone signal transduction(ko04075), terpenoid backbone biosynthesis (ko00900) and monoterpenoid biosynthesis (ko00902) pathways were enriched significantly. The gene expression of differential genes were linked to the monoterpene content, and the geraniol synthase (CbGES), alcohol dehydrogenase (CbADH), geraniol 8-hydroxylase-like (CbCYP76B6-like) and 8-hydroxygeraniol dehydrogenase (Cb10HGO) were upregulated in the citral-type, indicating that they were associated with high content of geraniol and citral. The activities of CbGES and CbADH in citral type were higher than in non-citral type, which was corroborated by enzyme-linked immunosorbent assay (ELISA). This study on the accumulation mechanism of citral provides a theoretical basis for the development of essential oil of C. bodinieri.

Influence of Curcuma Longa extract in citral addition on functional properties of thin films with triple-layer structure based on furcellaran and gelatin

In this study, we obtained triple-layer films based on furcellaran and gelatin, in which the middle layer was enriched with extract of Curcuma longa in citral. This newly developed material underwent a comprehensive characterisation process to identify significant improvements in its functional properties. Both SEM, XRD and FTIR analyzes indicated the formation of interactions not only between the components but also between the film layers. Notably, the incorporation of the natural extract led to a significant reduction in solubility, decreasing it from 74.79 % to 57.25 %, while enhancing thermal stability expressed as a melting point elevating it from 147.10 °C in the control film to 158.80 °C in the film with the highest concentration of the active ingredient. Simultaneously, the addition of this active ingredient resulted in decreased water contact angle (WCA) values, rendering the film more hydrophilic. The produced films exhibit great promise as packaging materials, particularly within the food industry, and the conducted research is marked by its forward-looking and developmental approach.

Design of three-component essential oil extract mixture from Cymbopogon flexuosus, Carum carvi, and Acorus calamus with enhanced antioxidant activity

The development of novel antioxidant compounds with high efficacy and low toxicity is of utmost importance in the medicine and food industries. Moreover, with increasing concerns about the safety of synthetic components, scientists are beginning to search for natural sources of antioxidants, especially essential oils (EOs). The combination of EOs may produce a higher scavenging profile than a single oil due to better chemical diversity in the mixture. Therefore, this exploratory study aims to assess the antioxidant activity of three EOs extracted from Cymbopogon flexuosus, Carum carvi, and Acorus calamus in individual and combined forms using the augmented-simplex design methodology. The in vitro antioxidant assays were performed using DPPH and ABTS radical scavenging approaches. The results of the Chromatography Gas-Mass spectrometry (CG-MS) characterization showed that citral (29.62%) and niral (27.32%) are the main components for C. flexuosus, while D-carvone (62.09%) and D-limonene (29.58%) are the most dominant substances in C. carvi. By contrast, β-asarone (69.11%) was identified as the principal component of A. calamus (30.2%). The individual EO exhibits variable scavenging activities against ABTS and DPPH radicals. These effects were enhanced through the mixture of the three EOs. The optimal antioxidant formulation consisted of 20% C. flexuosus, 53% C. carvi, and 27% A. calamus for DPPHIC50. Whereas 17% C. flexuosus, 43% C. carvi, and 40% A. calamus is the best combination leading to the highest scavenging activity against ABTS radical. These findings suggest a new research avenue for EOs combinations to be developed as novel natural formulations useful in food and biopharmaceutical products.

In Vitro Antioxidant and In Vivo Antigenotoxic Features of a Series of 61 Essential Oils and Quantitative Composition-Activity Relationships Modeled through Machine Learning Algorithms

The antioxidant activity of essential oils (EOs) is an important and frequently studied property, yet it is not sufficiently understood in terms of the contribution of EOs mixtures' constituents and biological properties. In this study, a series of 61 commercial EOs were first evaluated as antioxidants in vitro, following as closely as possible the cellular pathways of reactive oxygen species (ROS) generation. Hence, EOs were assessed for the ability either to chelate metal ions, thus interfering with ROS generation within the respiratory chain, or to neutralize 2,2-diphenyl-1-picrylhydrazyl (DPPH•) and lipid peroxide radicals (LOO•), thereby halting lipid peroxidation, as well as to neutralize 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid cation radicals (ABTS•+) and hydroxyl radicals (OH•), thereby preventing the ROS species from damaging DNA nucleotides. Showing noteworthy potencies to neutralize all of the radicals at the ng/mL level, the active EOs were also characterized as protectors of DNA double strands from damage induced by peroxyl radicals (ROO•), emerging from 2,2'-azobis-2-methyl-propanimidamide (AAPH) as a source, and OH•, indicating some genome protectivity and antigenotoxicity effectiveness in vitro. The chemical compositions of the EOs associated with the obtained activities were then analyzed by means of machine learning (ML) classification algorithms to generate quantitative composition-activity relationships (QCARs) models (models published in the AI4EssOil database available online). The QCARs models enabled us to highlight the key features (EOSs' chemical compounds) for exerting the redox potencies and to define the partial dependencies of the features, viz. percentages in the mixture required to exert a given potency. The ML-based models explained either the positive or negative contribution of the most important chemical components: limonene, linalool, carvacrol, eucalyptol, α-pinene, thymol, caryophyllene, p-cymene, eugenol, and chrysanthone. Finally, the most potent EOs in vitro, Ylang-ylang (Cananga odorata (Lam.)) and Ceylon cinnamon peel (Cinnamomum verum J. Presl), were promptly administered in vivo to evaluate the rescue ability against redox damage caused by CCl4, thereby verifying their antioxidant and antigenotoxic properties either in the liver or in the kidney.

Comparative Chemical Composition and Acetylcholinesterase (AChE) Inhibitory Potential of Cinnamomum camphora and Cinnamomum tamala

Cinnamomum species have applications in the pharmaceutical and fragrance industry for wide biological and pharmaceutical activities. The present study investigates the chemical composition of the essential oils extracted from two species of Cinnamomum namely C. tamala and C. camphora. Chemical analysis showed E-cinnamyl acetate (56.14 %), E-cinnamaldehyde (20.15 %), and linalool (11.77 %) contributed as the major compounds of the 95.22 % of C. tamala leaves essential oil found rich in phenylpropanoids (76.96 %). C. camphora essential oil accounting for 93.57 % of the total oil composition was rich in 1,8-cineole (55.84 %), sabinene (14.37 %), and α-terpineol (10.49 %) making the oil abundant in oxygenated monoterpenes (70.63 %). Furthermore, the acetylcholinesterase inhibitory activity for both the essential oils was carried out using Ellman's colorimetric method. The acetylcholinesterase inhibitory potential at highest studied concentration of 1 mg/mL was observed to be 46.12±1.52 % for C. tamala and 53.61±2.66 % for C. camphora compared to the standard drug physostigmine (97.53±0.63 %) at 100 ng/ml. These multiple natural aromatic and fragrant characteristics with distinct chemical compositions offered by Cinnamon species provide varied benefits in the development of formulations that could be advantageous for the flavor and fragrance industry.

Thymus richardii subsp. nitidus (Guss.) Jalas Essential Oil: An Ally against Oral Pathogens and Mouth Health

The genus Thymus L., belonging to the Lamiaceae family, contains about 220 species with a distribution that mainly extends in Europe, northwest Africa, Ethiopia, Asia, and southern Greenland. Due to their excellent biological properties, fresh and/or dried leaves and aerial parts of several Thymus ssp. have been utilized in the traditional medicine of many countries. To evaluate not only the chemical aspects but also the biological properties, the essential oils (EOs), obtained from the pre-flowering and flowering aerial parts of Thymus richardii subsp. nitidus (Guss.) Jalas, endemic to Marettimo Island (Sicily, Italy), were investigated. The chemical composition of the EOs, obtained by classical hydrodistillation and GC-MS and GC-FID analyses, showed the occurrence of similar amounts of monoterpene hydrocarbons, oxygenated monoterpenes, and sesquiterpene hydrocarbons. The main constituents of the pre-flowering oil were β-bisabolene (28.54%), p-cymene (24.45%), and thymol methyl ether (15.90%). The EO obtained from the flowering aerial parts showed as principal metabolites β-bisabolene (17.91%), thymol (16.26%), and limonene (15.59%). The EO of the flowering aerial parts, and its main pure constituents, β-bisabolene, thymol, limonene, p-cymene, and thymol methyl ether were investigated for their antimicrobial activity against oral pathogens and for their antibiofilm and antioxidant properties.

Variations in Essential Oils from the Leaves of Cinnamomum bodinieri in China

Cinnamomum plants are rich in natural essential oils, which are widely used as materials in the fragrance, insecticidal, antibacterial agent, pharmaceutical, and food industries; however, few studies have investigated the essential oil components of Cinnamomum bodinieri. Therefore, this study investigated the diversity of essential oils from the leaves of 885 individual C. bodinieri plants across 32 populations in five provinces. Essential oils were extracted by hydrodistillation, and then qualitative and quantitative analyses of the compounds were performed by GC-MS and GC-FID. A total of 87 chemical constituents were identified in the essential oils, including 33 monoterpenes, 48 sesquiterpenes, and six other compounds. The average oil yield was 0.75%, and individual oil yields ranged from 0.01% to 4.28%. A total of 16 chemotypes were classified according to variations in the essential oil chemical constituents of C. bodinieri, among which the camphor-type, citral-type, and eucalyptol-type were dominant. Moreover, the borneol-type, cymol-type, elemol-type, methylisoeugenol-type, and selina-6-en-4-ol-type were reported in C. bodinieri for the first time. The yield and principal components of the essential oils were mainly affected by altitude, temperature, and sunshine duration, among which altitude had the most significant effect; thus, low-altitude areas are more suitable for the synthesis and accumulation of essential oils. Based on the different characteristics of the essential oils in the leaves of C. bodinieri, several excellent populations and individuals were identified in this study. Moreover, the findings provide a foundation for breeding superior varieties and studying essential oil biosynthesis mechanisms in the future.

Hybrid Microcapsules for Encapsulation and Controlled Release of Rosemary Essential Oil

The foremost objective of this work is to assess the microcapsules composition (polymer-based and polymer/clay-based) effect, on the release of rosemary essential oil into w/o medium and evaluate their antioxidant activity. Calcium alginate (CA) and calcium alginate/montmorillonite hybrid (CA-MTN) microcapsules were developed following an ionotropic crosslinking gelation and were used as host materials for the encapsulation of rosemary essential oil. The unloaded/loaded CA and hybrid CA-MTN microcapsules were characterized by Fourier transform infra-red (FT-ATR) spectroscopy, thermal analysis (TGA), scanning electron microscopy (SEM) and DPPH assay. The evaluation of the microcapsule's physicochemical properties has shown that the clay filling with montmorillonite improved the microcapsule's properties. The encapsulation efficiency improved significantly in hybrid CA-MTN microcapsules and exhibited higher values ranging from 81 for CA to 83% for hybrid CA-MTN and a loading capacity of 71 for CA and 73% for hybrid CA-MTN, owing to the large adsorption capacity of the sodic clay. Moreover, the hybrid CA-MTN microcapsules showed a time-extended release of rosemary essential oil compared to CA microcapsules. Finally, the DPPH assay displayed a higher reduction of free radicals in hybrid CA-MNT-REO (12.8%) than CA-REO (10%) loaded microcapsules. These results proved that the clay-alginate combination provides microcapsules with enhanced properties compared to the polymer-based microcapsules.