Encapsulation of Hemp (Cannabis sativa L.) Essential Oils into Nanoemulsions for Potential Therapeutic Applications: Assessment of Cytotoxicological Profiles.

Industrial hemp (Cannabis sativa L.), due to its bioactive compounds (terpenes and cannabinoids), has gained increasing interest in different fields, including for medical purposes. The evaluation of the safety profile of hemp essential oil (EO) and its encapsulated form (nanoemulsion, NE) is a relevant aspect for potential therapeutic applications. This study aimed to evaluate the toxicological effect of hemp EOs and NEs from cultivars Carmagnola CS and Uso 31 on three cell lines selected as models for topical and inhalant administration, by evaluating the cytotoxicity and the cytokine expression profiles. Results show that EOs and their NEs have comparable cytotoxicity, if considering the quantity of EO present in the NE. Moreover, cells treated with EOs and NEs showed, in most of the cases, lower levels of proinflammatory cytokines compared to Etoposide used as a positive control, and the basal level of inflammatory cytokines was not altered, suggesting a safety profile of hemp EOs and their NEs to support their use for medical applications.

Comprehensive Evaluation of the Antibacterial and Antifungal Activities of Carlina acaulis L. Essential Oil and Its Nanoemulsion.

Plants are considered to be an excellent source of new compounds with antibiotic activity. Carlina acaulis L. is a medicinal plant whose essential oil (EO) is mainly characterized by the polyacetylene carlina oxide, which has antimicrobial properties. The aim of this study was to evaluate the antimicrobial and antifungal activities of C. acaulis EO, carlina oxide, and nanoemulsion (NE) containing the EO. The EO was obtained through plant roots hydrodistillation, and carlina oxide was purified from it through silica gel column chromatography. The NE containing C. acaulis EO was prepared with the high-pressure homogenization method, and the minimum inhibitory concentration (MIC) was determined against several bacterial and fungal strains for all the C. acaulis-derived products. The latter resulted active versus all the screened Gram-positive bacterial strains and also on all the fungal strains with low MIC values. For yeast, the EO and carlina oxide showed good MIC values. The EO-NE demonstrated a better activity than the pure EO on all the tested bacterial and fungal strains. The results suggest that C. acaulis-derived products could be potential candidates for the development of natural antibacterial and antifungal agents.

Activity of essential oil-based microemulsions against Staphylococcus aureus biofilms developed on stainless steel surface in different culture media and growth conditions.

Food safety is a fundamental concern for both consumers and the food industry, especially as the numbers of reported cases of food-associated infections continue to increase. Industrial surfaces can provide a suitable substrate for the development and persistence of bacterial organized in biofilms that represent a potential source of food contamination. The negative consumer perception of chemical disinfectants has shifted the attention to natural substances, such as plant extracts. The aim of this study was to investigate the possibility of using the essential oils (EOs) in the fight against S. aureus biofilms. First, the Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), Minimum Biofilm Inhibitory Concentration (MBIC), Minimum Biofilm Eradication Concentration (MBEC) of eleven EOs against S. aureus were determined. Cinnamomum cassia and Salvia officinalis EOs showed the greatest antibacterial properties with 1.25% MIC and MBC, 1.25% MBIC and 2.5% MBEC respectively. Gas Chromatography/Mass Spectrometry analysis revealed cinnamaldehyde (82.66%) and methoxy cinnamaldehyde (10.12%) as the most abundant substances of C. cassia, while cis-thujone (23.90%), camphor (19.22%) and 1.8-cineole (10.62%) of S. officinalis. Three different microemulsions, formulated with C. cassia, S. officinalis or both, were finally tested against S. aureus biofilms in different culture media and growth conditions, causing a >3 logarithmic reductions in S. aureus 24h-old biofilms and desiccated biofilms, and up to 68% of biofilm removal after 90min of exposure. The obtained data suggest the potential use of EOs, alone or in combination, for the formulation of sanitizers as alternative or in support in the disinfection of contaminated surfaces.

Evaluation of thermosensitive poloxamer 407 gel systems for the sustained release of estradiol in a fish model.

The purpose of this study was to develop and evaluate a delivery system comprising a thermosensitive gel for the sustained release of steroidal hormones in fish, over an extended period of time after a single intramuscular (i.m.) injection and for the improved reproductive performance in fish. Controlled delivery systems based on thermosensitive gels are easy to prepare, low cost and high versatility dosage forms, which have been shown to be effective in several animal species for sustained release of hormones. In this work, a thermosensitive gel system based on poloxamer 407 in water:ethanol medium, able to work as a prolonged release carrier for 17ß-estradiol (E2), has been developed. Such a system was able to solubilize the lipophilic E2 and to gel at the required water temperature for fish rearing (20°C). Moreover, the system exhibited the best injection condition at temperatures below 15°C when the system behaved as a low viscosity Newtonian liquid. The thermosensitive gel system was tested in vivo in the fish model, Carassius auratus, and the results compared with a single i.m. injection of E2 dissolved in corn-oil and other relevant control systems not containing E2. The results were particularly interesting, since fish injected with the E2 thermosensitive gel formulation, showed significantly higher levels of the circulating hormone than corn oil-E2 treated animals at 72 and 96h after injection. In addition, the thermogel system was able to sustain the plasma level of E2 for about 11days. The increased plasma levels of E2 were also accompanied by maintained higher values of plasma vitellogenin (VTG), thus suggesting that the thermosensitive polymer based delivery system could prevent rapid hepatic clearance of E2, resulting in prolonged stimulation of estrogen receptor-mediated pathways in goldfish.

Rheological evaluation of silicon/carbopol hydrophilic gel systems as a vehicle for delivery of water insoluble drugs.

The present study analyzed the thickening properties of Carbopol 974 and 971 in a 50:50 mixture of water/Silsense A-21, a new cationic silicon miscible in any proportion with water. Samples were prepared by simply dispersing different Carbopol amounts (0.5-4%) at room temperature or at 70 degrees C without neutralizing. Temperature sweep and time sweep analysis did not reveal significant structural changes at increasing temperature in the samples prepared following the first procedure. On the other hand systems obtained at 70 degrees C possessed higher elastic character particularly at polymer concentration higher than 2% (w/v). Analysis of the G' and G'' vs frequency curves by using different fitting equations (linear fitting, power law) gave information about the viscoelastic properties of the systems. The fitting of the frequency spectra and the calculation of the relaxation times from the master curves outlined the structural differences within the samples prepared with the two different procedures, confirming stronger gel-like behaviour for the samples prepared by the heating procedure. High preparation temperature promoted the polymer-solvent interactions, aiding the solvation of Carbopol. Heating facilitated polymer-solvent and polymer-polymer interaction, giving rise to a better organised structure typical of gel-like systems. Furthermore this preparation method provided good stability properties as shown by the stress sweeps tests performed during the three months of storage. The interpretation of the rheological results was supported by statistical analysis. A design methodology (screening and optimisation) was also applied in order evaluate the influence on dynamic rheological moduli of several parameters (polymer type and concentration, preparation method, temperature of the tests). This last method showed the relevance of the interaction of two main factors: polymer concentration and preparation procedure. Thus, statistical analysis confirmed that temperature increased the polymer-solvent interaction and improved the viscoelastic properties of the systems, particularly when Carbopols were present in considerable amounts.