A review on colloidal delivery vehicles using carvacrol as a model bioactive compound

Carvacrol and Thymol Hybrids: Potential Anticancer and Antibacterial Therapeutics

Cancer is ranked among lethal diseases globally, and the increasing number of cancer cases and deaths results from limited access to effective therapeutics. The use of plant-based medicine has been gaining interest from several researchers. Carvacrol and its isomeric compound, thymol, are plant-based extracts that possess several biological activities, such as antimalarial, anticancer, antifungal, and antibacterial. However, their efficacy is compromised by their poor bioavailability. Thus, medicinal scientists have explored the synthesis of hybrid compounds containing their pharmacophores to enhance their therapeutic efficacy and improve their bioavailability. Hence, this review is a comprehensive report on hybrid compounds containing carvacrol and its isomer, thymol, with potent anticancer and antibacterial agents reported between 2020 and 2024. Furthermore, their structural activity relationship (SAR) and recommended future strategies to further enhance their therapeutic effects will be discussed.

An ecofriendly coaxial antibacterial and anticorrosion nanofiber pullulan-ethyl cellulose embedded with carvacrol coating for protection against marine corrosion

Coaxial electrospun coatings with antibacterial and anticorrosion properties have a marked potential to protect against corrosion in marine environments. Ethyl cellulose is a promising biopolymer for corrosion caused by microorganisms owing to its high mechanical strength, nontoxicity, and biodegradability. In this study, a coaxial electrospun coating loaded with antibacterial carvacrol (CV) in the core and anticorrosion pullulan (Pu) and ethyl cellulose (EC) as a shell layer was successfully fabricated. The formation of core-shell structure was confirmed using transmission electron microscopy. Pu-EC@CV coaxial nanofiber had small diameters, uniform distribution, smooth surface, strong hydrophobicity, and no fractures. Electrochemical impedance spectroscopy was used to analyze corrosion of the electrospun coating surface in a medium containing bacterial solution. The results indicated significant corrosion resistance of the coating surface. In addition, the antibacterial activity and mechanism of coaxial electrospun were studied. The Pu-EC@CV nanofiber coating exhibited excellent antibacterial properties by effectively increasing the permeability of cell membranes and killing bacteria, as determined by plate counts, scanning electron microscopy, cell membrane permeability, and the activity of alkaline phosphatase. In summary, the coaxial electrospun pullulan-ethyl cellulose embedded with CV coating can be used as antibacterial and anticorrosion materials and may have potential applications in the field of marine corrosion.

Sophorolipid-based microemulsion delivery system: Multifaceted enhancement of physicochemical properties of xanthohumol

Xanthohumol (XN) has numerous compelling physiological activities, but the poor solubility and stability severely limit its utilization. Therefore, a microemulsion (ME) delivery system based on biosurfactant sophorolipids (SLs) was established and its improvement on physicochemical properties of XN was investigated. The results showed that the systems increased the solubility of XN by about 4000 times, and its half-life during storage was extended to over 150 days. Partial replacement of Tween 80 with SL did not greatly affect their ability to form O/W subregions (in the high aqueous phase), but further improved the solubilization efficiency, storage stability, and antioxidant properties of XN. In vitro models revealed the release profile of XN from the systems followed non-Fickian diffusion, and the ME structure markedly strengthened its digestive stability and bioaccessibility. These results indicated that SL-based ME systems had great potential as a green solubilization and delivery method for XN and other hydrophobic drugs.

Carvacrol-loaded nanoemulsions produced with a natural emulsifier for lettuce sanitization

Carvacrol is an antimicrobial agent that shows potential for eliminating microorganisms in vegetables, increasing food safety. However, intense odor and low water solubility of carvacrol are limiting factors for its application for fresh vegetables sanitization, which can be overcome by nanotechnology. Two different nanoemulsions containing carvacrol (11 mg/mL) were developed by probe sonication: carvacrol-saponin nanoemulsion (CNS) and carvacrol-polysorbate 80 nanoemulsion (CNP). Formulations presented appropriate droplet sizes (from 74.7 nm to 168.2 nm) and high carvacrol encapsulation efficiency (EE) (from 89.5 % to 91.5 %). CNS showed adequate droplet size distribution (PDI < 0.22) and high zeta potential values (around -30 mV) compared to CNP, with saponin chosen for the following experiments. Carvacrol nanoemulsions presented Bacterial Inactivation Concentration (BIC) against the Salmonella cocktail from 5.51 to 0.69 mg/mL and for the E. coli cocktail from 1.84 to 0.69 mg/mL. Among all tested nanoemulsions, CNS1 presented the lowest BIC (0.69 mg/mL) against both bacterial cocktails. Damage to bacterial cells in lettuce treated with nanoemulsion was confirmed by scanning electron microscopy. For lettuce sanitization, CNS1 showed a similar effect to unencapsulated carvacrol, with a high bacterial reduction (>3 log CFU/g) after lettuce immersion for 15 min at 2 × BIC. Using the same immersion time, the CNS1 (2 × BIC) demonstrated equal or better efficacy in reducing both tested bacterial cocktails (>3 log CFU/g) when compared to acetic acid (6.25 mg/mL), citric acid (25 mg/mL), and sodium hypochlorite solution (150 ppm). Lettuce immersed in CNS1 at both concentrations (BIC and 2 × BIC) did not change the color and texture of leaves, while the unencapsulated carvacrol at 2 × BIC darkened them and reduced their firmness. Consequently, carvacrol-saponin nanoemulsion (CNS1) proved to be a potential sanitizer for lettuce.

Study of nanoemulsions using carvacrol/MCT-(Oleic acid-potassium oleate)/ Tween 80 ®- water system by low energy method

Carvacrol is studied in different fields due to its microbial and antioxidant properties. Its use is limited because of the water insolubility and its strong taste. To overcome these problems, carvacrol has been successfully loaded into nanoemulsions. The low-energy emulsification method Phase Inversion Composition (PIC) is used to prepare oil-in-water nanoemulsions in the carvacrol/medium chain triglycerides (MCT)-(oleic acid-potassium oleate/Tween 80 ®)-water system. Oleic acid acts as a co-surfactant when it is neutralized with KOH along the emulsification path changing the spontaneous curvature of the interface when increasing the HLB number from 1 for the oleic acid to 20 for the potassium oleate and, therefore, changing the HLB number of the surfactant mixture. The phases diagrams are studied in order to understand the behaviour of the system and to establish the composition range where nanoemulsions can be obtained. Nanoemulsions are formed when the emulsification path crosses a region of direct or planar structure without excess of oil. Experimental design is performed in order to study the influence of composition variables as carvacrol/MCT ratio and (oleic-oleate)/Tween 80 ® ratio (OL-OT/T80 ratio) on the diameter of the nanoemulsions and their stability. It has been observed the importance of the HLB number of the surfactants mixture in order to obtain small-sized stable nanoemulsions. Surface response graphic shows that (OL-OT)/T80 ratio is a significant parameter in the mean diameter of the nanoemulsions. A minimum diameter is obtained for a (OL-OT)/T80 ratio 45/55 due to the fact that ratio is near the preferred HLB of the oil mixture and the emulsification path contains a wide liquid crystal monophasic region with all the oil incorporated in the structure. Diameters of 19 nm for carvacrol/MCT ratio of 30/70 or diameters of 30 nm for ratios of 45/55 with high stability values presented a good potential to be incorporated into edible films in the future. Regarding nanoemulsions stability an optimum value is also observed for a carvacrol/MCT ratio. The addition of another carrier oil as olive oil instead of MCT showed an improvement of the nanoemulsions stability against Ostwald ripening, probably due to the smaller solubility of olive oil. The use of olive oil does not significantly change the diameter of the nanoemulsion.

Carvacrol-A Natural Phenolic Compound with Antimicrobial Properties

The main purpose of this article is to present the latest research related to selected biological properties of carvacrol, such as antimicrobial, anti-inflammatory, and antioxidant activity. As a monoterpenoid phenol, carvacrol is a component of many essential oils and is usually found in plants together with its isomer, thymol. Carvacrol, either alone or in combination with other compounds, has a strong antimicrobial effect on many different strains of bacteria and fungi that are dangerous to humans or can cause significant losses in the economy. Carvacrol also exerts strong anti-inflammatory properties by preventing the peroxidation of polyunsaturated fatty acids by inducing SOD, GPx, GR, and CAT, as well as reducing the level of pro-inflammatory cytokines in the body. It also affects the body's immune response generated by LPS. Carvacrol is considered a safe compound despite the limited amount of data on its metabolism in humans. This review also discusses the biotransformations of carvacrol, because the knowledge of the possible degradation pathways of this compound may help to minimize the risk of environmental contamination with phenolic compounds.

Therapeutic application of carvacrol: A comprehensive review

Carvacrol is a major natural constituent and is significantly present as an essential oil in aromatic plants and is well known for its numerous biological activities. Therapeutic properties of carvacrol have been demonstrated as anti-oxidant, anticancer, diabetes prevention, cardioprotective, anti-obesity, hepatoprotective and reproductive role, antiaging, antimicrobial, and immunomodulatory properties. The carvacrol biosynthesis has been mediated through mevalonate pathway. Carvacrol has the anticancer ability against malignant cells via decreasing the expressions of matrix metalloprotease 2 and 9, inducing apoptosis, enhancing the expression of pro-apoptotic proteins, disrupting mitochondrial membrane, suppressing extracellular signal-regulated kinase 1/2 mitogen-activated protein kinase signal transduction, and also decreasing the phosphoinositide 3-kinase/protein kinase B. It also decreased the concentrations of alanine aminotransferase, alkaline phosphatase and aspartate aminotransferase, and gamma-glutamyl transpeptidase as well as also restored liver function, insulin level, and plasma glucose level. Carvacrol also has been found to exert antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Coagulase-negative staphylococcus, Salmonella spp., Enterococcus sp. Shigella, and Escherichia coli. The current review article summarizes the health-promoting perspectives of carvacrol through various pathways.

Microencapsulation of Carvacrol by Complex Coacervation of Walnut Meal Protein Isolate and Gum Arabic: Preparation, Characterization and Bio-Functional Activity

As a natural phenolic compound, carvacrol has attracted much attention due to its excellent antibacterial and antioxidant activities. However, its application is limited due to its instability, such as easy volatilization, easy oxidation, etc. Protein-polysaccharide interactions provide strategies for improving their stability issues. In this study, the plant-based carvacrol microcapsules via complex coacervation between walnut meal protein isolate (WMPI) and gum Arabic (GA) has been fabricated and characterized. The formation conditions of WMPI-GA coacervates were determined by some parameters, such as pH, zeta-potential, and turbidity. The optimum preparation conditions were achieved at pH 4.0 with a WMPI-to-GA ratio of 6:1 (w/w). The mean particle size, loading capacity (LC), and encapsulation efficiency (EE) of the microcapsules were 43.21 μm, 26.37%, and 89.87%, respectively. Fourier transform infrared spectroscopy (FT-IR) and fluorescence microscopy further confirmed the successful microencapsulation of carvacrol. The microencapsulation of carvacrol improved the thermal stability of the free carvacrol. The swelling capacity results indicated that it could resist gastric acid, and facilitate its intestinal absorption. Meanwhile, the carvacrol molecules trapped within the microcapsules could be continuously released in a concentration-dependent manner. Furthermore, the microcapsules presented good antioxidant activity and antibacterial activity against the Gram-negative (E. coli) and the Gram-positive (S. aureus) bacteria. These results indicated that the obtained carvacrol microcapsules have a potential application value as a food preservative in the food industry.

Surface Morphology-Enhanced Delivery of Bioinspired Eco-Friendly Microcapsules

We report the development of novel mineralized protein microcapsules to address critical challenges in the environmental impact and performance of consumer, pharmaceutical, agrochemical, cosmetic, and paint products. We designed environment-friendly capsules composed of proteins and biominerals as an alternative to solid microplastic particles or core-shell capsules made of nonbiodegradable synthetic polymeric resins. We synthesized mineralized capsule surface morphologies to mimic the features of natural pollens, which dramatically improved the deposition of high value-added fragrance chemicals on target substrates in realistic application conditions. A mechanistic model accurately captures the observed enhanced deposition behavior and shows how surface features generate an adhesive torque that resists shear detachment. Mineralized protein capsule performance is shown to depend both on material selection that determines van der Waals attraction and on capsule-substrate energy landscapes as parameterized by a geometric taxonomy for surface morphologies. These findings have broad implications for engineering multifunctional environmentally friendly delivery systems.

Preparation and characterization of chitosan/pullulan film loading carvacrol for targeted antibacterial packaging of chilled meat

In this research, the common microorganisms in chilled meat were used as the targeted antibacterial objects. Chitosan, pullulan, and carvacrol were chosen to prepare the edible antibacterial film. The effects of different concentrations of carvacrol on the microstructure, physical properties and antibacterial properties of the films were investigated. The results showed that the antibacterial activity of chitosan/pullulan film (CS/PU) was unsatisfactory, when carvacrol was added, the antibacterial activity of the chitosan/pullulan/carvacrol film (CS/PU/CAR) improved significantly (p < 0.05), and the water vapor permeability (WVP) of the CS/PU/CAR decreased significantly (p < 0.05). When the carvacrol concentration was higher than 1.25% (w/v), the tensile strength and percentage elongation at break of the CS/PU/CAR increased significantly (p < 0.05), and the CS/PU/CAR exhibited satisfying antibacterial activity against the common bacteria in chilled meat such as Pseudomonas fluorescens, Listeria monocytogenes, Escherichia coli, Pseudomonas putida, Enterobacter cloacae, and Staphylococcus aureus. Finally, the CS/PU/CAR film was applied to the preservation of chilled goat meat and extended the shelf life of goat meat to more than 15 days. These results suggested that the targeted CS/PU/CAR film can be used as biodegradable films for the active packaging of chilled meat.

Valorization of Spent Coffee Grounds as a Natural Source of Bioactive Compounds for Several Industrial Applications-A Volatilomic Approach

Coffee is one of the most popular beverages worldwide, whose production and consumption result in large amounts of waste, namely spent coffee grounds, constituting an important source of compounds for several industrial applications. This work focused on the establishment of the volatile fingerprint of five spent coffee grounds from different geographical origins using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME/GC-MS), as a strategy to identify volatile organic metabolites (VOMs) with potential application in the food industry as antioxidant, anti-inflammatory, and antiproliferative agents. One hundred eleven VOMs belonging to different chemical families were identified, of which 60 were found in all spent coffee grounds analyzed. Furanic compounds (34%), nitrogen compounds (30%), and esters (19%) contributed significant to the total volatile fingerprint. The data obtained suggest that spent coffee grounds have great potential to be used as raw material for different approaches in the food industry towards the development of new food ingredients or products for human consumption, in addition to pharmaceutical and cosmetic applications, namely as antioxidant (e.g., limonene, carvacrol), antimicrobial (e.g., pyrrole-2-carboxaldehyde, β-myrcene) and anti-inflammatory (e.g., furfural, 2-furanmethanol) agents, promoting their integral valorization within the circular bioeconomy concept.

Nanocarriers for Sustainable Active Packaging: An Overview during and Post COVID-19

Lockdown has been installed due to the fast spread of COVID-19, and several challenges have occurred. Active packaging was considered a sustainable option for mitigating risks to food systems during COVID-19. Biopolymeric-based active packaging incorporating the release of active compounds with antimicrobial and antioxidant activity represents an innovative solution for increasing shelf life and maintaining food quality during transportation from producers to consumers. However, food packaging requires certain physical, chemical, and mechanical performances, which biopolymers such as proteins, polysaccharides, and lipids have not satisfied. In addition, active compounds have low stability and can easily burst when added directly into biopolymeric materials. Due to these drawbacks, encapsulation into lipid-based, polymeric-based, and nanoclay-based nanocarriers has currently captured increased interest. Nanocarriers can protect and control the release of active compounds and can enhance the performance of biopolymeric matrices. The aim of this manuscript is to provide an overview regarding the benefits of released active compound-loaded nanocarriers in developing sustainable biopolymeric-based active packaging with antimicrobial and antioxidant properties. Nanocarriers improve physical, chemical, and mechanical properties of the biopolymeric matrix and increase the bioactivity of released active compounds. Furthermore, challenges during the COVID-19 pandemic and a brief post-COVID-19 scenario were also mentioned.