Influence of Nanoencapsulation Using High-Pressure Homogenization on the Volatile Constituents and Anticancer and Antioxidant Activities of Algerian Saccocalyx satureioides Coss. et Durieu

Effect of Microfluidization on the Volatiles and Antibacterial, Antifungal, and Cytotoxic Activities of Algerian Satureja hortensis L. Oil-Loaded Nanoemulsions: In Vitro and In Silico Study

This study aimed to increase the stability and solubility of the Algerian Satureja hortensis L. (ASHO) essential oil through nanoencapsulation. Nanoemulsions of ASHO (MF-ASHEO) were developed to evaluate their antioxidant and antimicrobial potential, stability, and cytotoxicity using microfluidization at 150 MPa for five cycles. MF-ASHO showed 8 compounds (99.56%) vs ASHEO's 26 compounds (95.46%). Carvacrol increased to 94.51%, replacing γ-terpinene, which decreased to 0.43%. The MF-ASHEO nanoemulsion had a mean particle size of 41.72 nm, a monomodal size distribution pattern, a mean ζ-potential of -39.4 mV, and a polydispersity index (PDI) mean value of 0.291. Micrographs showed spherical nanoparticles with varying diameters in nm. ASHEO was more toxic than MF-ASHEO against HepG2, Vero, and WI-38, according to the MTT and WST-1 assays. ASHEO demonstrated antiradical and antibacterial activity and inhibited biofilm formation. It also had an enhanced antifungal effect and reduced mycotoxin production. The MF-ASHEO sample showed no activity except in reducing mycotoxin production, where it performed better than ASHEO. In silico and ADME results confirmed the inhibitory action of carvacrol on the key enzymes of the aflatoxin biosynthetic mechanism and the target proteins associated with bactericidal/bacteriostatic effects. The microfluidization process dramatically affects not only the oil's volatile content but also its biological activity.

Analytical Method for Quantifying Monoterpenoids (p-Cymene and Myrcene) in Nanoemulsions Using High-Performance Liquid Chromatography

BACKGROUND

Myrcene and cymene, aromatic monoterpenes found in plants and essential oils, possess distinctive aromatic qualities. However, their volatility and limited solubility pose challenges in precise handling and formulation. Meanwhile, nanoemulsions emerge as promising drug delivery systems, improving the bioavailability and stability of these active ingredients.

OBJECTIVE

This article aimed to develop an HPLC method for the quantification of two monoterpenoids, p-cymene and myrcene, in nanoemulsions.

METHOD

The method used a Phenomenex® Synergi™ Fusion-RP column (150 mm × 4.6 mm id, 4 μm particle size) on an HPLC system with isocratic elution. The mobile phase was composed of acetonitrile and water (60:40, v/v) and was validated in terms of specificity, linearity, accuracy, precision, robustness, and selectivity.

RESULTS

The method provided accurate and precise results with a correlation coefficient of 0.999 and RSD values of less than 2%. The method can be used for quality control of nanoemulsions containing these monoterpenoids and as a reference for future studies on their efficacy and stability.

CONCLUSIONS

The study demonstrates the feasibility of using HPLC for the quantification of monoterpenoids in nanoemulsions and its potential as a quality control tool for nanoemulsion-based drug delivery systems.

HIGHLIGHTS

The method's accuracy, precision, and reliability, as evidenced by high correlation coefficients and low RSD values, underscore its suitability for ensuring the consistent formulation of these monoterpenoid-containing nanoemulsions, while also serving as a reference point for future research endeavors in this field.

Microfluidizing Technique Application for Algerian Cymbopogon citratus (DC.) Stapf Effects Enhanced Volatile Content, Antimicrobial, and Anti-Mycotoxigenic Properties

Medicinal plant extracts are a promising source of bioactive minor contents. The present study aimed to evaluate the distinguished volatile content of Algerian Cymbopogon citratus (DC.) Stapf before and after the microfluidization process and their related antimicrobial and anti-mycotoxigenic impacts and changes. The GC-MS apparatus was utilized for a comparative examination of Algerian lemongrass essential oil (LGEO) with its microfluidization nanoemulsion (MF-LGEO) volatile content. The MF-LGEO was characterized using Zetasizer and an electron microscope. Cytotoxicity, antibacterial, and antifungal activities were determined for the LGEO and MF-LGEO. The result reflected changes in the content of volatiles for the MF-LGEO. The microfluidizing process enhanced the presence of compounds known for their exceptional antifungal and antibacterial properties in MF-LGEO, namely, neral, geranial, and carvacrol. However, certain terpenes, such as camphor and citronellal, were absent, while decanal, not found in the raw LGEO, was detected. The droplet diameter was 20.76 ± 0.36 nm, and the polydispersity index (PDI) was 0.179 ± 0.03. In cytotoxicity studies, LGEO showed higher activity against the HepG2 cell line than MF-LGEO. Antibacterial LGEO activity against Gram-positive bacteria recorded an inhibitory zone from 41.82 ± 2.84 mm to 58.74 ± 2.64 mm, while the zone ranged from 12.71 ± 1.38 mm to 16.54 ± 1.42 mm for Gram-negative bacteria. Antibacterial activity was enhanced to be up to 71.43 ± 2.54 nm and 31.54 ± 1.01 nm for MF-LGEO impact against Gram-positive and Gram-negative pathogens. The antifungal effect was considerable, particularly against Fusarium fungi. It reached 17.56 ± 1.01 mm and 13.04 ± 1.37 mm for LGEO and MF-LGEO application of a well-diffusion assay, respectively. The MF-LGEO was more promising in reducing mycotoxin production in simulated fungal growth media due to the changes linked to essential compounds content. The reduction ratio was 54.3% and 74.57% for total aflatoxins (AFs) and ochratoxin A (OCA) contents, respectively. These results reflect the microfluidizing improvement impact regarding the LGEO antibacterial, antifungal and anti-mycotoxigenic properties.

Advances and trends in encapsulation of essential oils

There is a huge concern regarding the potential carcinogenic and mutagenic risks associated with the usage of synthetic chemicals as preservatives in various consumer products such as food and pharmaceutical formulations. In this aspect, there is a need for the development of alternative natural preservatives to replace these synthetic chemicals. More recently, naturally occurring essential oils have emerged as popular ingredients owing to their unique characteristics like antioxidant and antimicrobial activity, to enrich and enhance the functional properties of consumer products. However, due to their high volatility and hydrophobicity, their functionality is lost and their incorporation in aqueous products is challenging. One of the promising strategies to overcome this challenge is encapsulation which involves the entrapment of the essential oil inside a biocompatible material for its controlled release and increased bioavailability. Also, the choice of encapsulation method depends on the component to be encapsulated and the shell material. In this review, encapsulation in various colloidal systems that facilitate the potential delivery of essential oils is discussed. The focus is on encapsulation techniques along with their advantages and disadvantages, encapsulation efficiency, and in vitro release studies.

Anticancer Applications of Essential Oils Formulated into Lipid-Based Delivery Nanosystems

The use of natural compounds is becoming increasingly popular among patients, and there is a renewed interest among scientists in nature-based bioactive agents. Traditionally, herbal drugs can be taken directly in the form of teas/decoctions/infusions or as standardized extracts. However, the disadvantages of natural compounds, especially essential oils, are their instability, limited bioavailability, volatility, and often irritant/allergenic potential. However, these active substances can be stabilized by encapsulation and administered in the form of nanoparticles. This brief overview summarizes the latest results of the application of nanoemulsions, liposomes, solid lipid nanoparticles, and nanostructured lipid carriers used as drug delivery systems of herbal essential oils or used directly for their individual secondary metabolites applicable in cancer therapy. Although the discussed bioactive agents are not typical compounds used as anticancer agents, after inclusion into the aforesaid formulations improving their stability and bioavailability and/or therapeutic profile, they indicated anti-tumor activity and became interesting agents with cancer treatment potential. In addition, co-encapsulation of essential oils with synthetic anticancer drugs into nanoformulations with the aim to achieve synergistic effect in chemotherapy is discussed.

In Silico Study for Algerian Essential Oils as Antimicrobial Agents against Multidrug-Resistant Bacteria Isolated from Pus Samples

In the context of the globally growing problem of resistance to most used antibacterial agents, essential oils offer promising solutions against multidrug-resistant (MDR) bacterial pathogens. The present study aimed to evaluate the prevalence, etiology, and antibiotic-resistance profiles of bacteria responsible for pyogenic infections in Regional Military University Hospital of Constantine. Disc diffusion and broth microdilution (MIC) methods were used to evaluate the antimicrobial activity of essential oils from five Algerian aromatic plants growing wild in the north of Algeria-Salvia officinalis (Sage), Thymus vulgaris (Thyme), Mentha pulegium L. (Mentha), Rosmarinus officinalis (Rosemary), and Pelargonium roseum (Geranium)-against reference and MDR strains. During three months of the prospective study, 112 isolates out of 431 pus samples were identified. Staphylococcus aureus was the most predominant species (25%), followed by Klebsiella pneumoniae (21.42%), Pseudomonas aeruginosa (21%), and Escherichia coli (17.95%). Among pus isolates, 65 were MDR (58.03%). The radial streak-line assay showed that R. officinalis and M. pulegium L. had weak activity against the tested strains, whereas P. roseum showed no activity at all. Meanwhile, T. vulgaris was the most potent, with an inhibition zone of 12-26 mm and an MIC value ranging between 0.25 and 1.25%, followed by S. officinalis with an inhibition zone of 8-12 mm and an MIC value ranging between 0.62 and 2.5%. Generally, A. baumannii and S. aureus ATCC6538P were the most sensitive strains, whereas P. aeruginosa ATCC27853 was the most resistant strain to the oils. Gas chromatography-mass spectrometry analysis of chemical composition revealed the presence of borneol (76.42%) and thymol (17.69%) as predominant in thyme, whereas camphor (36.92%) and α- thujone (34.91%) were the major volatiles in sage. The in-silico study revealed that sesquiterpenes and thymol had the highest binding free energies against the vital enzymes involved in biosynthesis and repair of cell walls, proteins, and nucleic acids compared to monoterpenes. The results demonstrated that T. vulgaris and S. officinalis are ideal candidates for developing future potentially active remedies against MDR strains.

Prevention of Aflatoxin Occurrence Using Nuts-Edible Coating of Ginger Oil Nanoemulsions and Investigate the Molecular Docking Strategy

The modern utilization of essential oils such as ginger oil (GO) as an anti-aflatoxin represents a potential target for food preservation and safety; however, the mechanism of action is still unclear. Nanoemulsions, through an edible coating, can enhance the oil’s bioactivity, increase its hydrophilicity, and extend the final product’s shelf-life. In the present study, two edible films for the GO nanoemulsion were prepared by ultrasonication using carboxymethyl cellulose (FB1-GO) and sodium alginate (FB2-GO). The droplet size of FB2-GO was finer (126.54 nm) compared to FB1-GO (289.77 nm). Meanwhile, both had high stability proved by z-potential; +31.54 mV (FB1-GO) and +46.25 mV (FB2-GO) with low PDI values (<0.4). Using gas chromatography-mass spectrometry, the hydrodistilled GO showed 25 compounds, representing 99.17% of the total oil, with α-zingiberene (29.8%), geranial (10.87%), β-bisabolene (8.19%), and ar-curcumene (5.96%) as the predominant. A dramatic increase in α-zingiberene, α-bisabolene and ar-curcumene was due to the homogenization conditions in both FB1-GO and FB2-GO compared to the GO. The FB1-GO exhibited superior antibacterial activity against the examined strains of bacterial pathogens, while FB2-GO was more effective as an antifungal agent on the tested Aspergillus fungi strains. In a simulated liquid media, FB2-GO inhibited the total growth of fungi by 84.87−92.51% and showed the highest reduction in the aflatoxin amount produced. The in silico study presented that, among the GO volatile constituents, sesquiterpenes had the highest binding free energies against the enzymes responsible for aflatoxin production compared to monoterpenes. α-Bisabolene showed the highest affinity toward polyketide synthase (−7.5 Kcal/mol), while ar-curcumene was the most potent against cytochrome P450 monooxygenase (−8.3 Kcal/mol). The above findings clarify the reasons for aflatoxin reduction in simulated media during incubation with FB1-GO and FB2-GO.

Effect of Nanoencapsulation on the Antimicrobial and Antibiofilm Activities of Algerian Origanum glandulosum Desf. against Multidrug-Resistant Clinical Isolates

The emergence of multidrug-resistant (MDR) bacteria is a danger to public health and exposes patients to high risk, increasing morbidity and mortality worldwide. For this purpose, three months of evaluation of MDR’s prevalence and antimicrobial susceptibility patterns in the military regional university hospital of Constantine from different services and samples was carried out. Among a total of 196 isolates, 35.2% were MDR. The use of essential oils such as Origanum glandulosum Desf. as an alternative to antibiotics is attractive due to their rich content of bioactive compounds conferring many biological activities. Also, to overcome the drawbacks of using oils as the hydrophobicity and negative interaction with the environmental conditions, in addition to increasing their activity, encapsulation for the oil was performed using high-speed homogenization (HSH) into nanocapsules and high-pressure homogenization (HPH) into nanoemulsion. Nine volatile constituents were determined using gas chromatography-mass spectrometry analysis (GC-MS) in hydrodistilled oil with thymol, carvacrol, p-cymene, and γ-terpinene as dominants. A dramatic decrease in the major volatile components was observed due to the use of HSH and HPH but generated the same oil profile. The mean particle size of the nanoemulsion was 54.24 nm, while that of nanocapsules was 120.60 nm. The antibacterial activity of the oil and its nanoparticles was estimated on MDR isolates using the disk diffusion, aromatogram, and broth microdilution methods. Consistent with the differences in volatile constituents, the oil exhibited a higher antibacterial activity compared to its nanoforms with the diameters of the inhibition zone against E. coli (20 mm), S. aureus (35 mm), and A. baumannii (40 mm). Both formulations have shown relatively significant activity against the biofilm state at sub-inhibitory concentrations, where nanoemulsion was more potent than nanocapsules. The results obtained suggested that nanoformulations of essential oils are strongly recommended for therapeutic application as alternatives to antibiotics.

Preparation, Characterization, and Antioxidant Activity of Nanoemulsions Incorporating Lemon Essential Oil

Lemon essential oil (LEO) is a kind of citrus essential oil with antioxidant, anti-inflammatory, and antimicrobial activities, but low water solubility and biological instability hinder its industrial application. In this study, LEO was nanoemulsified to solve these problems. The preparation procedure of lemon essential oil nanoemulsions (LEO-NEs) was optimized, and the physicochemical characterization and antioxidant activities were explored. Single-factor experiments (SFEs) and response surface methodology (RSM) were conducted for the effects on the mean droplet size of LEO-NEs. Five factors of SFE which may influence the droplet size were identified: HLB value, concentration of essential oil, concentration of surfactant, ultrasonic power, and ultrasonic time. On the basis of the SFE, the RSM approach was used to optimize the preparation procedure to obtain LEO-NEs with the smallest droplet size. LEO-NEs exhibited good antioxidant activity when the HLB value was 13, content of surfactant was 0.157 g/mL, ultrasonic time was 23.50 min, and ultrasonic power was 761.65 W. In conclusion, these results can provide a good theoretical basis for the industrial application of lemon essential oil.

Spent Coffee Grounds Valorization as Bioactive Phenolic Source Acquired Antifungal, Anti-Mycotoxigenic, and Anti-Cytotoxic Activities

Spent coffee grounds (SCGs), which constitute 75% of original coffee beans, represent an integral part of sustainability. Contamination by toxigenic fungi and their mycotoxins is a hazard that threatens food production. This investigation aimed to examine SCGs extract as antimycotic and anti-ochratoxigenic material. The SCGs were extracted in an eco-friendly way using isopropanol. Bioactive molecules of the extract were determined using the UPLC apparatus. The cytotoxicity on liver cancer cells (Hep-G2) showed moderate activity with selectivity compared with human healthy oral epithelial (OEC) cell lines but still lower than the positive control (Cisplatin). The antibacterial properties were examined against pathogenic strains, and the antifungal was examined against toxigenic fungi using two diffusion assays. Extract potency was investigated by two simulated models, a liquid medium and a food model. The results of the extract showed 15 phenolic acids and 8 flavonoids. Rosmarinic and syringic acids were the most abundant phenolic acids, while apigenin-7-glucoside, naringin, epicatechin, and catechin were the predominant flavonoids in the SCGs extract. The results reflected the degradation efficiency of the extract against the growth of Aspergillus strains. The SCGs recorded detoxification in liquid media for aflatoxins (AFs) and ochratoxin A (OCA). The incubation time of the extract within dough spiked with OCA was affected up to 2 h, where cooking was not affected. Therefore, SCGs in food products could be applied to reduce the mycotoxin contamination of raw materials to the acceptable regulated limits.

[Rose-scented geranium essential oil from Algeria (Pelargonium graveolens L'Hérit.): Assessment of antioxidant, anti-inflammatory and anticancer properties against different metastatic cancer cell lines]

INTRODUCTION

The study of natural products is one of the strategies implemented for the discovery of new compounds that can be used in cancer therapy. Aromatic herbs and medicinal plants found in Algeria and their anti-angiogenesis and cytotoxic potentials against cancer have not been much explored.

OBJECTIVES

Our work aimed to evaluate the antioxidant, anti-inflammatory and anticancer properties of the essential oil (EO) extracted from rose-scented geranium (Pelargonium graveolens) and its major (citronellol) and characteristic (linalool) constituents.

RESULTS

The chemical composition of EO was determined with chromatographic analysis and revealed the presence of citronellol as the major compound (25.84%). A strong chelating power of terpene alcohols (IC50 = 1.58 ± 0.23 mg/mL for citronellol) was found, with a significant difference (p < 0.05) compared with the standard antioxidants used (L-ascorbic acid and butylated hydroxyanisole). The EO is distinguished by an interesting anti-inflammatory effect with the lowest IC₅₀ (4.63 ± 0.3 mg/mL), and it constitutes a good stabilizer of the erythrocyte membrane. Citronellol also exhibited the best anti-inflammatory effect (IC50 = 0.74 ± 0.09 mg/mL). We also assessed the anticancer effect of EO on two main pathways involved in cancer development, angiogenesis and cell proliferation, using in ovo bioassays with a chorio-allantoic membrane (CAM) of chicken eggs and in vitro assays of its cytotoxicity on different metastatic breast cancer (MDA-MB-231), gastric (AGS) and melanoma (MV3) cell lines. In the CAM model, the density of micro-vessels is 75 ± 10 in the group supplemented with EO compared to 140 ± 9 for the control group (b-FGF). In addition, the EO significantly reduced the number of newly formed vessels. The cytotoxicity was evaluated using the cell proliferation inhibition method and cell viability was measured using the MTT test. Results revealed that the treatment of cancer lines with different concentrations of EO reduces the rate of cell viability in a dose-dependent manner. EO showed the greatest cytotoxicity on the AGS line with an inhibition rate of 92.87 ± 0.13% at the highest dose (4 µL/mL), followed by the MV3 line (88.76 ± 0.96%). Conclusion and Prospects: Data demonstrated that rose-scented geranium EO has an anti-tumor potential on metastatic cancer cell lines. It is distinguished by its anti-proliferative, anti-angiogenic, and anti-inflammatory activities. Medicinal plants might contain new molecules, with new structures, which could become lead candidate among future anticancer drugs.

Development, Characterization, and Immunomodulatory Evaluation of Carvacrol-loaded Nanoemulsion

Carvacrol (CV) is an essential oil with numerous therapeutic properties, including immunomodulatory activity. However, this effect has not been studied in nanoemulsion systems. The objective of this study was to develop an innovative carvacrol-loaded nanoemulsion (CVNE) for immunomodulatory action. The developed CVNE comprised of 5% w/w oily phase (medium chain triglycerides + CV), 2% w/w surfactants (Tween 80^®/Span 80^®), and 93% w/w water, and was produced by ultrasonication. Dynamic light scattering over 90 days was used to characterize CVNE. Cytotoxic activity and quantification of cytokines were evaluated in peripheral blood mononuclear cell (PBMC) culture supernatants. CVNE achieved a drug loading of 4.29 mg/mL, droplet size of 165.70 ± 0.46 nm, polydispersity index of 0.14 ± 0.03, zeta potential of −10.25 ± 0.52 mV, and good stability for 90 days. CVNE showed no cytotoxicity at concentrations up to 200 µM in PBMCs. CV diminished the production of IL-2 in the PBMC supernatant. However, CVNE reduced the levels of the pro-inflammatory cytokines IL-2, IL-17, and IFN-γ at 50 µM. In conclusion, a stable CVNE was produced, which improved the CV immunomodulatory activity in PBMCs.

Polymeric Carriers Designed for Encapsulation of Essential Oils with Biological Activity

The article reviews the possibilities of encapsulating essential oils EOs, due to their multiple benefits, controlled release, and in order to protect them from environmental conditions. Thus, we present the natural polymers and the synthetic macromolecular chains that are commonly used as networks for embedding EOs, owing to their biodegradability and biocompatibility, interdependent encapsulation methods, and potential applicability of bioactive blend structures. The possibilities of using artificial intelligence to evaluate the bioactivity of EOs—in direct correlation with their chemical constitutions and structures, in order to avoid complex laboratory analyses, to save money and time, and to enhance the final consistency of the products—are also presented.