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Nanoformulations of encapsulating Essential Oil in polymeric nanocarriers with antioxidant and antibacterial properties
Abstract
Chitosan (CS) nano-carrier was used as an encapsulating agent for Peppermint Essential Oil (PO) by using two-steps method starting with emulsification and followed by ionic cross-linking method. The PO loaded chitosan colloidal nanoparticles were characterized by different techniques; Dynamic light scattering (DLS), Fourier transform infrared (FT-IR) spectroscopy, Thermogravimetric analysis (TGA), and powder X-ray diffraction (XRD). The morphology and size of CS/PO NPs were detected by Transmission electron microscopy (TEM) that showed spherical shape of the nanoparticles with an average size range below 100 nm. The EE % and LC % of CS/PO NPs reached 82% and 22%, respectively. Moreover, the PO nano-encapsulation improved the PO antioxidant activity by about 2 folds and showed superior antibacterial activity of CS/PO NPs against Staphylococcus aureus and Escherichia coli by about 99.9% and 97.5%, respectively. The results obtained will enhance the usage of nano-encapsulated PO in the Food and Pharmaceutical sectors.
... Source, drain and gate are made up of n-type doped silicon, whereas the island is made up of aluminium. The design compatibility allows SET to be fabricated with MOS on same silicon footprint with the CMOS processes [27]. is Tunneling junction capacitances on source as well as drain side are C T D = C T S = C J , control gate capacitance is C G , tunnel junction resistances are R T D = R T S = R T = 1M . ...
... Actual dimensions will depend on the fabrication facility. The dimensions are calculated using parallel plate capacitance [7,13,27] and considering SiO 2 as tunnel barriers and as gate dielectric. The SET MIB model is Written in Verilog-A language and it contains the behaviour of SET drain current with respect to design parameters and temperature [9]. ...
A novel hybrid silicon Single Electron Transistor Metal Oxide Semiconductor (SETMOS) logic is evaluated for its functionality and usability. Emphasis is given on obtaining functionality at ambient temperature with low power consumption and significant drive. Performance is evaluated with respect to 22 nm Complementary Metal Oxide Semiconductor (CMOS) technology and other popular hybrid SETMOS topologies. The results produced here not only comprehend performance of various SET-CMOS based logic architectures, but they are also closer to real values as they consider effect of parasitic in respective topologies. Proposed work is power efficient, scalable, accurate and process compatible logic design, which uses less hardware and operates at room temperature. It relies on CMOS compatible fabrication of Silicon SET and P-Type Metal Oxide Semiconductor (PMOS) on same chip footprint. When compared with contemporary SETMOS hybrid circuits, it offers 90.29 % power improvement at the cost of 16.53 % reduction in speed.
Essential oils are aromatic and volatile liquids extracted from plants. The chemicals in essential oils are secondary metabolites, which play an important role in plant defense as they often possess antimicrobial properties. The interest in essential oils and their application in food preservation has been amplified in recent years by an increasingly negative consumer perception of synthetic preservatives. Furthermore, food-borne diseases are a growing public health problem worldwide, calling for more effective preservation strategies. The antibacterial properties of essential oils and their constituents have been documented extensively. Pioneering work has also elucidated the mode of action of a few essential oil constituents, but detailed knowledge about most of the compounds' mode of action is still lacking. This knowledge is particularly important to predict their effect on different microorganisms, how they interact with food matrix components, and how they work in combination with other antimicrobial compounds. The main obstacle for using essential oil constituents as food preservatives is that they are most often not potent enough as single components, and they cause negative organoleptic effects when added in sufficient amounts to provide an antimicrobial effect. Exploiting synergies between several compounds has been suggested as a solution to this problem. However, little is known about which interactions lead to synergistic, additive, or antagonistic effects. Such knowledge could contribute to design of new and more potent antimicrobial blends, and to understand the interplay between the constituents of crude essential oils. The purpose of this review is to provide an overview of current knowledge about the antibacterial properties and antibacterial mode of action of essential oils and their constituents, and to identify research avenues that can facilitate implementation of essential oils as natural preservatives in foods.
In this study the composition and antimicrobial properties of essential oils obtained from Origanum onites, Mentha piperita, Juniperus exalsa, Chrysanthemum indicum, Lavandula hybrida, Rosa damascena, Echinophora tenuifolia, Foeniculum vulgare were examined. To evaluate the in vitro antibacterial activities of these eight aromatic extracts; their in vitro antimicrobial activities were determined by disk diffusion testing, according to the NCCLS criteria. Escherichia coli (ATTC 25922), Staphylococcus aureus (ATCC 25923) and Pseudomonas aeruginosa (ATTC 27853 were used as standard test bacterial strains. Origanum onites recorded antimicrobial activity against all test bacteria, and was strongest against Staphylococcus aureus. For Rosa damascena, Mentha piperita and Lavandula hybrida antimicrobial activity was recorded only to Staphylococcus aureus. Juniperus exalsa, and Chrysanthemum indicum exhibited antibacterial activities against both Staphylococcus aureus and Escherichia coli. We also examined the in vitro antimicrobial activities of some components of the essential oils and found some components with antimicrobial activity.
In the present investigation, essential oil (EO) and methanolic extract of Tunisian Mentha spicata leaves were tested for their chemical composition and biological activities. Results showed that EO was characterized by the predominance of oxygenated monoterpenes (92.18%), followed by monoterpene hydrocarbons and sesquiterpenes whose respective amounts were 2.74 and 3.1% of the whole EO. The main volatile compound of M. spicata EO was L-menthone, accounting for 32.74% of the total volatiles, followed by pulegone (26.67%). The phenolic composition of methanolic extracts was determined by reversed-phase high-performance liquid chromatography. The major flavonoid component was apigenin with a mean concentration of 38.4 mg/100 g dry weight. M. spicata leave extract tested for their antioxidant and antibacterial activities showed a significant antiradical and superoxide anion scavenging capacity in addition to the great potential for antimicrobial activities against the bacteria tested.
In this study, oregano essential oil (OEO) has been encapsulated in chitosan nanoparticles by a two-step method, i.e., oil-in-water emulsion and ionic gelation of chitosan with sodium tripolyphosphate (TPP). The success of OEO encapsulation was confirmed by Fourier transform infrared (FT-IR) spectroscopy, UV-vis spectrophotometry, thermogravimetric analysis (TGA) and X-ray diffraction (XRD) techniques. The obtained nanoparticles exhibited a regular distribution and spherical shape with size range of 40-80nm as observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). As determined by TGA technique, the encapsulation efficiency (EE) and loading capacity (LC) of OEO-loaded chitosan nanoparticles were about 21-47% and 3-8%, respectively, when the initial OEO content was 0.1-0.8g/g chitosan. In vitro release studies showed an initial burst effect and followed by a slow drug release.
The aims of this work were to study the antimicrobial activity of nine monoterpenes and the synergistic or antagonistic associations between them, and to relate water solubility, H-bonding and pKa values with antimicrobial activity. The minimum inhibitory concentrations (MICs) and minimum bactericidal concentration (MBCs) were determined. The MIC of carvacrol against S. aureus was 3.2 g/l and of thymol was 7.5 g/l. E. coli was resistant. Carvacrol and thymol were bactericidal. The associations geraniol/menthol against S. aureus and B. cereus and thymol/menthol against B. cereus were totally synergistic. Eugenol/geraniol displayed partial synergism against B. cereus. The other groups did not show any synergistic effect. Eugenol had the lowest pKa, followed by thymol and carvacrol. Eugenol had the highest total area and polar area and intermolecular and intramolecular hydrogen-bonding capacity, while carvacrol and thymol only had intermolecular hydrogen-bonding capacity. The terpenes alone and in combination were effective against microorganisms. Phenolic compounds were the most active terpenes. Associations between terpenes were related to the chemical structure. Studies on the antimicrobial activity of associations of terpenes will advance the search for new alternatives for food preservation. Copyright © 2009 John Wiley & Sons, Ltd.
The fabrication of carvacrol-loaded chitosan nanoparticles was achieved by a two-step method, i.e., oil-in-water emulsion and ionic gelation of chitosan with pentasodium tripolyphosphate. The obtained particles possessed encapsulation efficiency (EE) and loading capacity (LC) in the ranges of 14-31% and 3-21%, respectively, when the initial carvacrol content was 0.25-1.25 g/g of chitosan. The individual particles exhibited a spherical shape with an average diameter of 40-80 nm, and a positively charged surface with a zeta potential value of 25-29 mV. The increment of initial carvacrol content caused a reduction of surface charge. Carvacrol-loaded chitosan nanoparticles showed antimicrobial activity against Staphylococcus aureus, Bacillus cereus and Escherichia coli with an MIC of 0.257 mg/mL. The release of carvacrol from chitosan nanoparticles reached plateau level on day 30, with release amounts of 53% in acetate buffer solution with pH of 3, and 23% and 33% in phosphate buffer solutions with pH of 7 and 11, respectively. The release mechanism followed a Fickian behavior. The release rate was superior in an acidic medium to either alkaline or neutral media, respectively.
Supercritical fluid extraction of essential oils is one of the most widely discussed applications inthe supercritical fluid literature. Peppermint leaf oil was isolated by a supercritical fluidextraction using CO2 in which the extraction was followed by a two-stage fractional separation.Chemical analysis revealed that oils extracted under different supercritical fluid extractionconditions possessed a widely different percentage composition. Oil obtained byhydrodistillation was also compared with the extracted oils. Although practically the samecompounds were present in the hydrodistilled oil, its composition was similar to supercriticalfluid extraction oil extracted under non-optimised conditions. The oil obtained at optimumsupercritical fluid extraction conditions (p = 90 bar, T = 40 C) had a fragrance that betterresembled that of the peppermint leaves used for the extraction of the oils.
Essential oils are known to possess antimicrobial and antioxidant activity while chitosan is a biocompatible polymer with antibacterial activity against a broad spectrum of bacteria. In this work, nanoparticles with both antioxidant and antibacterial properties were prepared by grafting eugenol and carvacrol (two components of essential oils) on chitosan nanoparticles. Aldehyde groups were first introduced in eugenol and carvacrol, and the grafting of these oils to chitosan nanoparticles was carried out via the Schiff base reaction. The surface concentration of the grafted essential oil components was determined by X-ray photoelectron spectroscopy (XPS). The antioxidant activities of the carvacrol-grafted chitosan nanoparticles (CHCA NPs) and the eugenol-grafted chitosan nanoparticles (CHEU NPs) were assayed with diphenylpicrylhydrazyl (DPPH). Antibacterial assays were carried out with a representative gram-negative bacterium, Escherichia coli (E. coli) and a gram-positive bacterium, Staphylococcus aureus (S. aureus). The grafted eugenol and carvacrol conferred antioxidant activity to the chitosan nanoparticles, and the essential oil component-grafted chitosan nanoparticles achieved an antibacterial activity equivalent to or better than that of the unmodified chitosan nanoparticles. Cytotoxicity assays using 3T3 mouse fibroblast showed that the cytotoxicity of CHEU NPs and CHCA NPs were significant lower than those of the pure essential oils.
Preparation and antibacterial activity of chitosan nanoparticles
- L Qi
- Z Xu
- X Jiang
- C Hu
- X Zou
L. Qi, Z. Xu, X. Jiang, C. Hu, and X. Zou, "Preparation and antibacterial activity of chitosan
nanoparticles," Carbohydr. Res., vol. 339, no. 16, pp. 2693-2700, 2004.
In vitro release and biological activities of Carum copticum essential oil (CEO) loaded chitosan nanoparticles
- A Esmaeili
- A Asgari
A. Esmaeili and A. Asgari, "In vitro release and biological activities of Carum copticum essential oil
(CEO) loaded chitosan nanoparticles," Int. J. Biol. Macromol., vol. 81, pp. 283-290, Nov. 2015.
Proceedings of the Nanotech France 2018 International Conference (Nanotech France 2018)
Paris, France, June 27 -29, 2018
DOI: https://doi.org/10.26799/cp-nanotechfrance2018
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