Search Results (7)

Earth plasters have several advantages. Nevertheless, they are vulnerable when in contact with liquid water. For that reason, they have low durability when applied as an outdoor coating or in indoor areas with potential contact with water. In this study, the influence of six different surface treatments (traditional and innovative, based on raw materials and on waste) applied on a pre-mixed earth plaster, applied by a roller (r) or as a spray (s), was assessed. The treatments were: limewash (L), beeswax (BW), linseed oil (LO), graphene oxide dispersion (GO), water from paper immersion (WP) and water from gypsum plasterboard paper immersion (WPG). The application of L, BW and LO, despite the color change, improved the water resistance and the surface performance of the earth plaster (less than 80%–86%, 93%–98% and 97%–99% of mass loss from surface cohesion, from water erosion by dripping action and from dry abrasion, respectively, compared to the reference untreated plaster). However, the application of BW and LO had a negative effect on the hygroscopic capacity of the plaster (less than 28%–38% of water vapor adsorbed after 24 h and the MBV decreased 29%–50% compared to the reference plaster). Finally, the application of the remaining surface treatments did not significantly improve the characteristics of the plaster, having even worsened it in certain cases (more than 42%–149% of mass loss from water erosion, compared to the reference plaster). These results demonstrated that, among the treatments analyzed, the L, BW and LO treatments are the best options to apply on an earth plaster. In particular, the application of BW and LO are recommended in situations where it is necessary to improve water resistance and surface performance, and the hygroscopic capacity is not a conditioning characteristic, such as outdoor applications. Full article

With the increasing shortage of petroleum resources and the growing seriousness of environmental pollution, the exploitation and application of bio-based coatings derived from renewable resources have become increasingly important for the woodworking industry. Wood wax oil (WWO) is a new type of bio-based natural coating material that offers an eco-friendly solution for wood protection. This paper focused on the utilization of tung oil and beeswax as the primary raw materials for the preparation of wood wax oil. The WWO was based on the oxidation polymerization of tung oil, which served as the foundation for the preparation process. The effects of the photoinitiator TPO-L on the curing performance of the WWO were investigated, and the curing mechanism of the WWO system induced by photoinitiators was analyzed and characterized by infrared spectroscopy. Through ultraviolet irradiation experiments and coating quality tests, the effects of incremental photoinitiators on the properties of the surface drying time, gloss, color, hydrophobicity, and solution resistance of the treated ash wood were studied. The results indicated that the addition of photoinitiators was beneficial for the rapid polymerization of wood wax oil. A UV light intensity of 30 w was found to be sufficient to initiate the curing process. Specifically, when using TPO-L as the initiator at a concentration of 3 wt%, the surface could be surface-dried within 10 min under UV exposure. Under these curing conditions, wood wax oil coatings based on tung oil with comprehensive curing properties can be obtained. Additionally, adding 6% beeswax to the tung oil can effectively enhance the hydrophobicity of pure tung-oil-based wood protective coatings. Full article

Bee propolis has been touted as a natural antimicrobial agent with the potential to replace antibiotics. Numerous reports and reviews have highlighted the functionalities and applications of the natural compound. Despite much clamor for the downstream application of propolis, there remain many grounds to cover, especially in the upstream production, and factors affecting the quality of the propolis. Moreover, geopropolis and cerumen, akin to propolis, hold promise for diverse human applications, yet their benefits and intricate manufacturing processes remain subjects of intensive research. Specialized cement bees are pivotal in gathering and transporting plant resins from suitable sources to their nests. Contrary to common belief, these resins are directly applied within the hive, smoothed out by cement bees, and blended with beeswax and trace components to create raw propolis. Beekeepers subsequently harvest and perform the extraction of the raw propolis to form the final propolis extract that is sold on the market. As a result of the production process, intrinsic and extrinsic factors, such as botanical origins, bee species, and the extraction process, have a direct impact on the quality of the final propolis extract. Towards the end of this paper, a section is dedicated to highlighting the antimicrobial potency of propolis extract. Full article

Propolis or “bee glue” is a resinous waxy substance that is produced by honeybees (Apis mellifera) by mixing the exudates collected from plants, namely tree buds, sap flows, leaves, branches and barks with their saliva and beeswax. Propolis composition is very complex. Its main constituents are resins and volatiles originating from plants and wax added by the bee. The biological activity of propolis is assigned to these plant-derived substances. The main three types of propolis are European propolis, called poplar type propolis; Green Brazilian propolis (derived mainly from the leaf resin of Baccharis dracunculifolia) and Red Cuban propolis (from the floral resin of Clusia rosea). The plant’s source gives it a specific composition and properties for the propolis types that are coming from different regions of the world. For this reason, studies on the chemical composition of propolis as well as its botanical sources resulting in its geographically conditioned diversity, were a very good theme for the present Special Issue (SI) of Plants journal. The present SI contains nine original contributions addressing propolis plant sources, their chemical composition and different bioactive properties derived from this origin. The chemical composition of propolis that is made by the bees was also discussed, as well as the different medical activities of propolis extract. The papers cover a wide range of subjects, including (i) the plant species used by the bees as raw material for propolis production, (ii) the biological activities of plant extracts related to propolis, (iii) the chemical composition of different types of propolis, (iv) the biological activity of propolis, (v) propolis and human health, and (vi) synergism between plants and propolis in human health. The studies have been carried out in both in vitro and in vivo surveys and a wide range of geographic regions are covered in the sample collection. Full article

Atopic dermatitis (AD) is a chronic inflammatory skin disease that is difficult to treat. Traditional cold cream, a water-in-oil emulsion made from beeswax, is used to alleviate AD symptoms in clinical practice, although its effectiveness has not been scientifically proven. The addition of propolis has the potential to impart anti-inflammatory properties to cold cream. However, in high concentrations, propolis can trigger allergic reactions. Thus, the objective of this work was to develop a cold cream formulation based on purified beeswax containing the same amount of green propolis present in raw beeswax. The impact of adding this low propolis concentration to cold cream on AD control was evaluated in patients compared to cold cream without added propolis (CBlank). Raw beeswax was chemically characterized to define the propolis concentration added to the propolis-loaded cold cream (CPropolis). The creams were characterized as to their physicochemical, mechanical, and rheological characteristics. The effect of CPropolis and CBlank on the quality of life, disease severity, and skin hydration of patients with AD was evaluated in a triple-blind randomized preclinical study. Concentrations of 34 to 120 ng/mL of green propolis extract reduced TNF-α levels in LPS-stimulated macrophage culture. The addition of propolis to cold cream did not change the cream’s rheological, mechanical, or bioadhesive properties. The preclinical study suggested that both creams improved the patient’s quality of life. Furthermore, the use of CPropolis decreased the disease severity compared to CBlank. Full article

The use of lipid nanoparticles as drug delivery systems has been growing over recent decades. Their biodegradable and biocompatible profile, capacity to prevent chemical degradation of loaded drugs/actives and controlled release for several administration routes are some of their advantages. Lipid nanoparticles are of particular interest for the loading of lipophilic compounds, as happens with essential oils. Several interesting properties, e.g., anti-microbial, antitumoral and antioxidant activities, are attributed to carvacrol, a monoterpenoid phenol present in the composition of essential oils of several species, including Origanum vulgare, Thymus vulgaris, Nigellasativa and Origanum majorana. As these essential oils have been proposed as the liquid lipid in the composition of nanostructured lipid carriers (NLCs), we aimed at evaluating the influence of carvacrol on the crystallinity profile of solid lipids commonly in use in the production of NLCs. Different ratios of solid lipid (stearic acid, beeswax or carnauba wax) and carvacrol were prepared, which were then subjected to thermal treatment to mimic the production of NLCs. The obtained binary mixtures were then characterized by thermogravimetry (TG), differential scanning calorimetry (DSC), small angle X-ray scattering (SAXS) and polarized light microscopy (PLM). The increased concentration of monoterpenoid in the mixtures resulted in an increase in the mass loss recorded by TG, together with a shift of the melting point recorded by DSC to lower temperatures, and the decrease in the enthalpy in comparison to the bulk solid lipids. The miscibility of carvacrol with the melted solid lipids was also confirmed by DSC in the tested concentration range. The increase in carvacrol content in the mixtures resulted in a decrease in the crystallinity of the solid bulks, as shown by SAXS and PLM. The decrease in the crystallinity of lipid matrices is postulated as an advantage to increase the loading capacity of these carriers. Carvacrol may thus be further exploited as liquid lipid in the composition of green NLCs for a range of pharmaceutical applications. Full article

Lemon essential oil (LEO) is known for having excellent antioxidant properties with applications in the pharmaceutical, food and cosmetic sectors. However, its deficient stability to light and temperature compromise this activity. In this study, waxy emulsifiers, such as beewax, candelilla wax, carnauba wax, and ozokerite wax, were employed in order to create lipidic matrixes with LEO as a continuous phase by heating to 80 °C under homogenization, followed by rapid cooling to 25 °C. The thermal, microstructural, rheological, and antioxidant tests were then conducted on such matrixes. The difference in melting, crystallization, and gelling temperatures was explained by the diverse chemical composition (long-chain wax esters in carnauba wax having a high melting point, and short-chain fatty acids and hydrocarbons in beewax and ozokerite wax, respectively). Crystal habits of these matrix systems varied from grainy, oval, to fiber-like shape, whereas there was a prevalent orthorhombic allomorph. The alignment and reorganization of carnauba and candelilla wax crystals led to an increase in the matrix strength as compared to those of beeswax and ozokerite matrixes, which showed a weak texture and poor crystallization behavior. The last two matrix systems showed the best flow and extensibility. These lipidic matrixes showed potential use for topical applications having good oil retention capacity and better antioxidant properties as compared to the raw essential oil. Full article