Low energy nanoemulsions as carriers of thyme and lemon balm essential oils

Unveiling the Molecular Dynamics, Anticancer Activity, and Stability of Spearmint Oil Nanoemulsions with Triglycerides

Although spearmint oil (SMO) has various pharmacological properties, especially for cancer treatment, its low water solubility results in poor bioavailability. This limits its application as a medicine. One possible solution is to the use of SMO in the form of nanoemulsion, which has already been shown to have anticancer effects. However, the mechanism of SMO nanoemulsion formation remains unclear. The objective of this study was to use molecular dynamics (MD) for clarifying the formation of SMO nanoemulsion with triglycerides (trilaurin, tripalmitin, and triolein) and Cremophor RH40 (PCO40). Nanoemulsions with different SMO:triglyceride ratios and triglyceride types were prepared and analyzed for anticancer activity, droplet size, droplet morphology, and stability. Despite switching the type of carrier oil, SMO nanoemulsions retained strong anticancer effects. A ratio of 80SMO:20triglycerides produced the smallest droplets (<100 nm) and exhibited excellent physical stability after a temperature cycling test. MD simulations showed that polyoxyethylenes of PCO40 are located at the water interface, stabilizing the emulsion structure in an egglike layer. Droplet size correlated with triglyceride concentration, which was consistent with the experimental findings. Decreasing triglyceride content, except for the 90SMO:10triglyceride ratio, led to a decrease in droplet sizes. Hydrogen bond analysis identified interactions between triglyceride-PCO40 and carvone-PCO40. Geometry analysis showed PCO40 had an "L-like" shape, which maximizes the hydrophilic interfaces. These findings highlight the value of MD simulations in understanding the formation mechanism of SMO and triglyceride nanoemulsions. In addition, it might also be beneficial to use MD simulations before the experiment to select the potential composition for nanoemulsions, especially essential oil nanoemulsions.

Nanoemulsion-Based System as a Novel and Promising Approach for Enhancing the Antimicrobial and Antitumoral Activity of Thymus vulgaris (L.) Oil in Human Hepatocellular Carcinoma Cells

The utilisation of medicinal plants and their essential oils is receiving more attention due to the ineffectiveness of current therapeutic methods in the treatment of various cancers and the rising incidence of bacterial antibiotic resistance. Thymol, an active ingredient of Thymus vulgaris, is known to have hepatoprotective, antibacterial, and antioxidant properties. To overcome major obstacles to their usage, such as quick oxidation and high volatility, plant essential oils must be administered through a system to improve the delivery of their active pharmaceutical ingredient. The bioavailability of active substances may be enhanced by the colloidal dispersion nanoemulsion. Therefore, this study aims to derive a comparative evaluation of the thyme oil nanoemulsion formulation and the characterisation of its antibacterial and antitumorigenic activities. A nanoemulsion (NE) with a droplet size of 122.2 ± 1.079 nm was discovered to be stable and mono-dispersed for 4 months and inhibited the growth of B. subtilis, E. coli, P. aeruginosa, and S. aureus. It also displayed antitumorigenic capabilities in HepG2 cells by arresting the cell cycle in the G2/M phase and upregulating the gene expression levels of Bcl-2-associated X protein (Bax), Caspase 3, 8, and 9, as well as a concomitant concentration-dependent decrease in B-cell leukaemia/lymphoma 2 protein (BCL2). Along with an increase in inducible nitric oxide synthase (iNOS) levels, upregulation of the expression levels of the reactive oxygen species (ROS), mitogen-activated protein kinase (MAPK), and endoplasmic reticulum (ER) stress pathways was also seen, indicating of ROS formation in the cancer cells.

Citrus essential oils - Based nano-emulsions: Functional properties and potential applications

Citrus essential oils are natural products with various bioactive properties (e.g., antimicrobial, antioxidant, and antimutagenic activities), that are generally recognized as safe (GRAS) by Food and Drug Administration (FDA) to be used as flavorings and food additives. Nonetheless, due to their high volatility, low solubility in water, low thermal stability, susceptibility to oxidation, and strong flavor, their applications in the food industry are limited. Nanotechnology allows the incorporation of citrus essential oils into nano-emulsion systems, thus protecting them from the deterioration caused by external factors and maintaining or even improving their functional properties. This study aims to summarize the antioxidant, antimicrobial, and antimutagenic effects of the nano-emulsions based on essential oils from citrus peels with emphasis on their mechanisms of action and potential applications in, e.g., foods, pharmaceuticals, and cosmetics.

Carvacrol Microemulsion vs. Nanoemulsion as Novel Pork Minced Meat Active Coatings

Carvacrol is well documented for its antibacterial and antioxidant effects. However, its high volatility has directed researchers toward nanoencapsulation technology according to bioeconomy and sustainability trends. This study examined and compared free carvacrol (FC), carvacrol microemulsion (MC), carvacrol microemulsion busted with chitosan (MMC), and carvacrol nanoemulsions (NC) as active coatings on extending minced pork meat shelf life at 4 ± 1 °C for 9 days, focusing on microbiological, physiochemical, and sensory characteristics. The research involved pre-characterizing droplet sizes, evaluating antioxidants, and determining antibacterial efficacy. The results demonstrated that NC with a 21 nm droplet size exhibited the highest antioxidant and antibacterial activity. All coatings succeeded in extending the preservation of fresh minced pork meat in comparison to the free carvacrol sample (FC). The NC coating showed the highest extension of minced pork meat preservation and maintained meat freshness for 9 days, with a lower TBARs of 0.736 mg MDA/Kg, and effectively reduced mesophilic, lactic acid, and psychotrophic bacterial counts more significantly by 1.2, 2, and 1.3 log, respectively, as compared to FC. Sensory assessments confirmed the acceptability of NC and MCC coatings. Overall, the carvacrol-based nanoemulsion can be considered a novel antioxidant and antimicrobial active coating due to its demonstrated higher efficacy in all the examined tests performed.

Melissa officinalisessential oil loaded polycaprolactone membranes: evaluation of antimicrobial activities and cytocompatibility for tissue engineering applications

Antimicrobial biomaterials play important role in tissue engineering applications to protect damaged tissue from infections. The aim of this study is producing antimicrobial polycaprolactone (PCL) membranes by using a plant based antimicrobial agent. Therefore,Melissa officinalisessential oil (MEO) was investigated against ten types of microorganisms and remarkable antimicrobial activity was demonstrated. PCL:MEO membranes were prepared by solvent casting method by mixing MEO into PCL in various ratios (PCL:0M, PCL:0.25M, PCL:0.5M, and PCL:1M w/w). Water contact angle measurements showed that hydrophilicity of the membranes increased with increasing concentrations of MEO from 103.44° to 83.36° for PCL:0M and PCL:1M, respectively. It was determined that there was an inverse relationship between the MEO concentration and the mechanical properties. Notable antioxidant activity of PCL/MEO membranes was exhibited by the inhibition percent of 2,2-diphenyl-1-picrylhydrazyl (DPPH) which was increased from 24.74% to 44.79% for PCL:0M and PCL:1M, respectively. The antimicrobial activity of MEO was also highly maintained in PCL membranes. For PCL/MEO membranes, at least 99.9% of microorganisms were inhibited. Cytocompatibility of the membranes were investigated by resazurin assay, scanning electron microscopy analysis and 4',6-diamidino-2-phenylindole (DAPI) staining. PCL:0.25M and PCL:0.5M membranes supported the viability of L929 cells more than 87% when compared to PCL:0M membranes on day 6. However, the viability of L929 cells on PCL:1M membranes was about 43% indicating significant decrease on cellular activity. In conclusion, PCL:0.25M and PCL:0.5M membranes with their high antimicrobial activity, acceptable mechanical properties and cytocompatible properties, they can be considered as an alternative biomaterial for tissue engineering applications.

Production and characterization of sage seed gum bioactive film containing Zataria multiflora essential oil nanoemulsion

A bioactive film with two concentrations of sage seed gum (SSG) (1 % and 1.5 %) incorporating 2 % and 4 % Zataria multiflora essential oil (ZMEO) nanoemulsion was developed. Microbiological evaluation, including disc diffusion and time-kill tests, as well as mechanical and chemical characteristics namely film thickness, water-solubility, water vapor permeability, tensile strength and elongation at break, scanning electron microscopy (SEM), Fourier transform-infrared (FT-IR) analysis, antioxidant activity, and color analysis, were examined. Results showed that the antimicrobial properties of SSG films incorporating ZMEO nanoemulsion increased significantly (P < 0.05) by the multiplication of essential oil concentration. The films with 1 % SSG-4 % ZMEO showed acceptable antioxidant properties (∼65 %), and improved physical properties (508 % thickness increase, 56.63 % water solubility decrease, and 36.85 % water vapor permeability decrease), whereas tensile strength decreased only 29.8 %, and elongation increased 115 %. According to the results, SSG-ZMEO film may have positive potential impacts on increasing the shelf-life of foodstuffs.

Biotechnological Applications of Nanoencapsulated Essential Oils: A Review

Essential oils (EOs) are complex mixtures of volatile and semi-volatile organic compounds that originate from different plant tissues, including flowers, buds, leaves and bark. According to their chemical composition, EOs have a characteristic aroma and present a wide spectrum of applications, namely in the food, agricultural, environmental, cosmetic and pharmaceutical sectors. These applications are mainly due to their biological properties. However, EOs are unstable and easily degradable if not protected from external factors such as oxidation, heat and light. Therefore, there is growing interest in the encapsulation of EOs, since polymeric nanocarriers serve as a barrier between the oil and the environment. In this context, nanoencapsulation seems to be an interesting approach as it not only prevents the exposure and degradation of EOs and their bioactive constituents by creating a physical barrier, but it also facilitates their controlled release, thus resulting in greater bioavailability and efficiency. In this review, we focused on selecting recent articles whose objective concerned the nanoencapsulation of essential oils from different plant species and highlighted their chemical constituents and their potential biotechnological applications. We also present the fundamentals of the most commonly used encapsulation methods, and the biopolymer carriers that are suitable for encapsulating EOs.

Impact of Fixed Oil on Ostwald Ripening of Anti-Oral Cancer Nanoemulsions Loaded with Amomum kravanh Essential Oil

Recently, essential oil from Amomum kravanh (AMO) was reported to exert anti-oral cancer effects. Although it was more effective after being loaded into nanoemulsions, AMO without an Ostwald ripening inhibitor was unable to form stable nanoemulsions because of the Ostwald ripening phenomenon. In this study, we examined the influence of Ostwald ripening inhibitors, such as fixed oils and polyethylene glycol 4000 (PEG 4000), on nanoemulsion properties prepared by a phase inversion temperature method. Several fixed oils, including virgin coconut oil (VCO), palm oil (PMO), olive oil (OLO), and PEG 4000, were evaluated, and their Ostwald ripening inhibitory effects were compared. The results suggest that the type and ratio of AMO:fixed oils influence the formation and characteristics of nanoemulsions. PEG 4000 was unable to produce nanoemulsions; however, stable nanoemulsions with small droplet sizes were observed in preparations containing OLO and VCO at an AMO:fixed oil ratio of 80:20, which may be the result of specific molecular interactions among the components. Using an MTT assay, we demonstrated that the AMO:OLO (80:20) nanoemulsion produced the most significant cytotoxic effect on oral cancer cells with a percentage of 99.68 ± 0.56%. Furthermore, the AMO:OLO 80:20 nanoemulsion inhibits metastasis and induces oral cancer cell death through the intrinsic apoptosis pathway. In conclusion, AMO nanoemulsion with anti-oral cancer activity was successfully produced by varying the amount and type of fixed oils. In the future, this discovery may lead to the development of stable nanoemulsions employing additional volatile oils.