Encapsulation of the natural antioxidant aureusidin in biodegradable PLA nanoparticles

Development of a Polymeric Membrane Impregnated with Poly-Lactic Acid (PLA) Nanoparticles Loaded with Red Propolis (RP)

The main objectives of this study were to develop and characterize hydrophilic polymeric membranes impregnated with poly-lactic acid (PLA) nanoparticles (NPs) combined with red propolis (RP). Ultrasonic-assisted extraction was used to obtain 30% (w/v) red propolis hydroalcoholic extract (RPE). The NPs (75,000 g mol-1) alone and incorporated with RP (NPRP) were obtained using the solvent emulsification and diffusion technique. Biopolymeric hydrogel membranes (MNPRP) were obtained using carboxymethylcellulose (CMC) and NPRP. Their characterization was performed using thermal analysis, Fourier transform infrared (FTIR), total phenols (TPC) and flavonoids contents (TFC), and antioxidant activity through the radical scavenging assay with 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and Ferric reducing antioxidant power (FRAP). The identification and quantification of significant RP markers were performed through UPLC-DAD. The NPs were evaluated for particle size, polydispersity index, and zeta potential. The TPC for RPE, NPRP, and MNPRP was 240.3 ± 3.4, 191.7 ± 0.3, and 183.4 ± 2.1 mg EGA g-1, while for TFC, the value was 37.8 ± 0.9, 35 ± 3.9, and 26.8 ± 1.9 mg EQ g-1, respectively. Relevant antioxidant activity was also observed by FRAP, with 1400.2 (RPE), 1294.2 (NPRP), and 696.2 µmol Fe2+ g-1 (MNPRP). The primary markers of RP were liquiritigenin, isoliquiritigenin, and formononetin. The particle sizes were 194.1 (NPs) and 361.2 nm (NPRP), with an encapsulation efficiency of 85.4%. Thermal analysis revealed high thermal stability for the PLA, nanoparticles, and membranes. The DSC revealed no interaction between the components. FTIR allowed for characterizing the RPE encapsulation in NPRP and CMC for the MNPRP. The membrane loaded with NPRP, fully characterized, has antioxidant capacity and may have application in the treatment of skin wounds.

A comparative study of optimized naringenin nanoformulations using nano-carriers (PLA/PVA and zein/pectin) for improvement of bioavailability

Naringenin, a lipophilic flavanone of citrus fruits, was encapsulated for enhanced bioavailability using biodegradable polymers of polylactic acid/polyvinyl alcohol (PLA/PVA) as well as zein/pectin as P/P-Nar-NPs and Z/P-Nar-NPs, respectively. The formulation variables were optimized using response surface methodology to achieve smaller particle size with higher surface charge and encapsulation efficiencies. The optimized formulations were physically characterized by SEM, FTIR, TGA and XRD techniques. Compared to Z/P-Nar-NPs, the P/P-Nar-NPs had better encapsulation efficiency and sustained release of naringenin under simulated gastrointestinal conditions. Furthermore, the oral administration of single dose of free and nanoforms of naringenin in rats (90 mg/kg b.wt) showed higher efficacy of PLA/PVA in improving the relative bioavailability of naringenin (4.7-fold) as compared to the zein/pectin polymer (1.9-fold). Overall, the present study provides insights into the formulation performance of the encapsulated bioactive compound under different polymeric matrices.

Synthesis of Polyamide-Based Microcapsules via Interfacial Polymerization: Effect of Key Process Parameters

Polyamide microcapsules have gathered significant research interest during the past years due to their good barrier properties; however, the potential of their application is limited due to the fragility of the polymeric membrane. Fully aliphatic polyamide microcapsules (PA MCs) were herein prepared from ethylene diamine and sebacoyl chloride via interfacial polymerization, and the effect of key encapsulation parameters, i.e., monomers ratio, core solvent, stirring rate and time during the polymerization step, were examined concerning attainable process yield and microcapsule properties (shell molecular weight and thermal properties, MC size and morphology). The process yield was found to be mainly influenced by the nature of the organic solvent, which was correlated to the diffusion potential of the diamine from the aqueous phase to the organic core through the polyamide membrane. Thus, spherical microcapsules with a size between 14 and 90 μm and a yield of 33% were prepared by using toluene as core solvent. Milder stirring during the polymerization step led to an improved microcapsule morphology; yet, the substantial improvement of mechanical properties remains a challenge.

Antioxidant Activity of Encapsulated Extracts and Bioactives from Natural Sources

The low water solubility and low bioavailability of natural bioactive substances such as polyphenols and flavonoids, either in pure form or extracts, are a major concern in the pharmaceutical field and even on the food development sector. Although encapsulation has demonstrated success in addressing these drawbacks, it is important to evaluate the antioxidant activity of the encapsulated compounds. This article reviews the encapsulation of bioactive compounds from natural sources focusing their antioxidant activity after encapsulation. Attention is given to the methods and wall materials used, and the antioxidant activity methodologies (classical in vitro techniques such as DPPH, ORAC, FRAP and others, as well as in vivo/ex vivo tests to evaluate endogenous antioxidant enzymes or oxidative stress) applied to assess the antioxidant capacity are also comprehensively summarized.

Ketoconazole-loaded poly-(lactic acid) nanoparticles: Characterization and improvement of antifungal efficacy in vitro against Candida and dermatophytes

OBJECTIVE

In order to improve the effect of ketoconazole, poly-lactic acid (PLA) nanoparticles containing ketoconazole were prepared, characterized and tested against dermatophytes and Candida spp planktonic and biofilm cells.

METHODS

The ketoconazole-PLA nanoparticles obtained by nanoprecipitation were characterized using dynamic light scattering, scanning electron microscopy, transmission electron microscopy, and differential scanning calorimetry. In addition, quantification of encapsulated ketoconazole and the in vitro release profile were determined. Antifungal susceptibility tests against dermatophytes Trichophyton rubrum, Trichophyton mentagrophytes, and Microsporum gypseum and yeasts Candida albicans, C. dubliniensis, C. krusei, C. parapsilosis, and C. tropicalis were performed.

RESULTS

Spherical nanoparticles, with a mean diameter of 188.5nm and an encapsulation efficiency of 45% ketoconazole, were obtained. The nanoparticles containing ketoconazole had superior antifungal activity against all tested fungi strains than free ketoconazole. Inhibition of yeast biofilm formation was also achieved.

CONCLUSION

Ketoconazole-PLA nanoparticles resulted in better antifungal activity of ketoconazole nanoparticles than free drug against dermatophytes and Candida species, indicating a promising tool for the development of therapeutic strategies.

Nanoantioxidants: Recent Trends in Antioxidant Delivery Applications

Antioxidants interact with free radicals, terminating the adverse chain reactions and converting them to harmless products. Antioxidants thus minimize the oxidative stress and play a crucial role in the treatment of free radicals-induced diseases. However, the effectiveness of natural and/or synthetic antioxidants is limited due to their poor absorption, difficulties to cross the cell membranes, and degradation during delivery, hence contributing to their limited bioavailability. To address these issues, antioxidants covalently linked with nanoparticles, entrapped in nanogel, hollow particles, or encapsulated into nanoparticles of diverse origin have been used to provide better stability, gradual and sustained release, biocompatibility, and targeted delivery of the antioxidants with superior antioxidant profiles. This review aims to critically evaluate the recent scientific evaluations of nanoparticles as the antioxidant delivery vehicles, as well as their contribution in efficient and enhanced antioxidant activities.

Anti-inflammatory effects of Aureusidin in LPS-stimulated RAW264.7 macrophages via suppressing NF-κB and activating ROS- and MAPKs-dependent Nrf2/HO-1 signaling pathways

Aureusidin, a naturally-occurring flavonoid, is found in various plants of Cyperaceae such as Heleocharis dulcis (Burm. f.) Trin., but its pharmacological effect and active mechanism are rarely reported. This study aimed to investigate the anti-inflammatory effect and action mechanism of Aureusidin in LPS-induced mouse macrophage RAW264.7 cells. The results suggested that lipopolysaccharide (LPS)-induced nitric oxide (NO), tumor necrosis factor-α (TNF-α) and prostaglandin E2 (PGE2) production were obviously inhibited by Aureusidin. Moreover, Aureusidin also significantly decreased the mRNA expression of various inflammatory factors in LPS-stimulated RAW264.7 cells. Furthermore, mechanistic studies showed that Aureusidin significantly inhibited nuclear transfer of nuclear factor-κB (NF-κB), while increasing the nuclear translocation of nuclear factor E2-related factor 2 (Nrf2) as well as expression of Nrf2 target genes such as heme oxygenase (HO-1) and NAD(P)H:quinone oxidoreductase 1 (NQO1), but the addition of the HO-1 inhibitor Sn-protoporphyrin (Snpp) significantly abolished the anti-inflammatory effect of Aureusidin in LPS-stimulated RAW264.7 cells, confirming the view that HO-1 was involved in the anti-inflammatory effect. In addition, Aureusidin increased the levels of reactive oxygen species (ROS) and mitogen-activated protein kinase (MAPK) phosphorylation in RAW264.7 cells. Antioxidant N-acetylcysteine (NAC) or three MAPK inhibitors blocked the nuclear translocation of Nrf2 and HO-1 expression induced by Aureusidin, indicating that Aureusidin activated the Nrf2/HO-1 signaling pathway through ROS and MAPKs pathways. At the same time, co-treatment with the NAC blocked the phosphorylation of MAPKs. Results from molecular docking indicated that Aureusidin inhibited the NF-κB pathway by covalently binding to NF-κB. Thus, Aureusidin exerted the anti-inflammatory activity through blocking the NF-κB signaling pathways and activating the MAPKs and Nrf2/HO-1 signaling pathways. Based on the above results, Aureusidin may be an attractive therapeutic candidate for the inflammation-related diseases.

Encapsulation of Mentha pulegium Essential Oil in Yeast Cell Microcarriers: An Approach to Environmentally Friendly Pesticides

A green approach for the encapsulation of Mentha pulegium essential oil in commercial baker's yeast and its evaluation as a pesticide against the insect pest Myzus persicae are presented. Upon treating aqueous yeast cell dispersion with the essential oil, the formation of essential-oil-loaded microparticles of about 9 μm is observed, with a loading capacity ranging from 29 to 36%, depending upon the encapsulation conditions. The thermal properties of the microparticles were characterized using differential scanning calorimetry and thermogravimetric analysis, confirming the protection of the essential oil from the cells. Encapsulation prolonged the insecticidal activity of the essential oil by 3 days.

Unintended effects of drug carriers: Big issues of small particles

Humoral and cellular host defense mechanisms including diverse phagocytes, leukocytes, and immune cells have evolved over millions of years to protect the body from microbes and other external and internal threats. These policing forces recognize engineered sub-micron drug delivery systems (DDS) as such a threat, and react accordingly. This leads to impediment of the therapeutic action, extensively studied and discussed in the literature. Here, we focus on side effects of DDS interactions with host defenses. We argue that for nanomedicine to reach its clinical potential, the field must redouble its efforts in understanding the interaction between drug delivery systems and the host defenses, so that we can engineer safer interventions with the greatest potential for clinical success.

Encapsulation of Antifouling Organic Biocides in Poly(lactic acid) Nanoparticles

The scope of the current research was to assess the feasibility of encapsulating three commercial antifouling compounds, Irgarol 1051, Econea and Zinc pyrithione, in biodegradable poly(lactic acid) (PLA) nanoparticles. The emulsification–solvent evaporation technique was herein utilized to manufacture nanoparticles with a biocide:polymer ratio of 40%. The loaded nanoparticles were analyzed for their size and size distribution, zeta potential, encapsulation efficiency and thermal properties, while the relevant physicochemical characteristics were correlated to biocide–polymer system. In addition, the encapsulation process was scaled up and the prepared nanoparticles were dispersed in a water-based antifouling paint in order to examine the viability of incorporating nanoparticles in such coatings. Metallic specimens were coated with the nanoparticles-containing paint and examined regarding surface morphology.

Encapsulation of Olive Leaves Extracts in Biodegradable PLA Nanoparticles for Use in Cosmetic Formulation

The aim of the current work was to encapsulate olive leaves extract in biodegradable poly(lactic acid) nanoparticles, characterize the nanoparticles and define the experimental parameters that affect the encapsulation procedure. Moreover, the loaded nanoparticles were incorporated in a cosmetic formulation and the stability of the formulation was studied for a three-month period of study. Poly(lactic acid) nanoparticles were prepared by the nanoprecipitation method. Characterization of the nanoparticles was performed using a variety of techniques: size, polydispersity index and ζ-potential were measured by Dynamic Light Scattering; morphology was studied using Scanning Electron Microscopy; thermal properties were investigated using Differential Scanning Calorimetry; whereas FT-IR spectroscopy provided a better insight on the encapsulation of the extract. Encapsulation Efficiency was determined indirectly, using UV-Vis spectroscopy. The loaded nanoparticles exhibited anionic ζ-potential, a mean particle size of 246.3 ± 5.3 nm (Pdi: 0.21 ± 0.01) and equal to 49.2%, while olive leaves extract release from the nanoparticles was found to present a burst effect at the first 2 hours. Furthermore, the stability studies of the loaded nanoparticles’ cosmetic formulation showed increased stability compared to the pure extract, in respect to viscosity, pH, organoleptic characteristics, emulsions phases and grid.

Encapsulation of Oregano (Origanum onites L.) Essential Oil in β-Cyclodextrin (β-CD): Synthesis and Characterization of the Inclusion Complexes

The aim of the present work was to study the encapsulation of Origanum onites L. essential oil (oregano EO) in β-cyclodextrin (β-CD) inclusion complexes (ICs), using the co-precipitation method. The formed β-CD-oregano EO ICs were characterized by diverse methods, such as Dynamic Light Scattering (DLS), FT-IR spectroscopy, Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), Nuclear Magnetic Resonance (NMR) spectroscopy and Scanning Electron Microscopy (SEM). UV-Vis spectroscopy was used for the determination of the inclusion efficacy and the study of the encapsulated oregano EO release profile. The interactions between host (β-CD) and guest (oregano EO) in the formed ICs were proven by the FT-IR, DSC, TG and NMR analyses. The ICs, which derived from different batches, presented nanoscale size (531.8 ± 7.7 nm and 450.3 ± 11.5 nm, respectively), good size dispersion (0.308 ± 0.062 and 0.484 ± 0.029, respectively) and satisfactory stability in suspension (ζ-potential = -21.5 ± 1.2 mV and -30.7 ± 1.8 mV). Inclusion efficiency reached up to 26%, whereas the oregano EO release from the ICs followed a continuous delivery profile for up to 11 days, based on in vitro experiments. The formed ICs can find diverse applications, such as in the preparation of films for active packaging of food products, in personal care products for the improvement of their properties (e.g., antioxidant, antimicrobial, etc.), as well as in insect repellent products.

Systems Pharmacological Approach of Pulsatillae Radix on Treating Crohn's Disease

In East Asian traditional medicine, Pulsatillae Radix (PR) is widely used to treat amoebic dysentery and renowned for its anti-inflammatory effects. This study aimed to confirm evidence regarding the potential therapeutic effect of PR on Crohn's disease using a system network level based in silico approach. Study results showed that the compounds in PR are highly connected to Crohn's disease related pathways, biological processes, and organs, and these findings were confirmed by compound-target network, target-pathway network, and gene ontology analysis. Most compounds in PR have been reported to possess anti-inflammatory, anticancer, and antioxidant effects, and we found that these compounds interact with multiple targets in a synergetic way. Furthermore, the mRNA expressions of genes targeted by PR are elevated significantly in immunity-related organ tissues, small intestine, and colon. Our results suggest that the anti-inflammatory and repair and immune system enhancing effects of PR might have therapeutic impact on Crohn's disease.

Antimicrobial activity of a new synthetic peptide loaded in polylactic acid or poly(lactic-co-glycolic) acid nanoparticles against Pseudomonas aeruginosa, Escherichia coli O157:H7 and methicillin resistant Staphylococcus aureus (MRSA)

Nanocarrier systems are currently being developed for peptide, protein and gene delivery to protect them in the blood circulation and in the gastrointestinal tract. Polylactic acid (PLA) and poly(lactic-co-glycolic) acid (PLGA) nanoparticles loaded with a new antimicrobial GIBIM-P5S9K peptide were obtained by the double emulsion solvent extraction/evaporation method. PLA- and PLGA-NPs were spherical with sizes between 300 and 400 nm for PLA and 200 and 300 nm for PLGA and <0.3 polydispersity index as determined by dynamic light scattering and scanning electron microscopy), having the zeta potential of >20 mV. The peptide-loading efficiency of PLA-NP and PLGA-NPs was 75% and 55%, respectively. PLA- and PLGA-NPs released around 50% of this peptide over 8 h. In 10% human sera the size of peptide loaded PLA- and PLGA-NPs increased between 25.2% and 39.3%, the PDI changed from 3.2 to 5.1 and the surface charge from -7.15 to 14.6 mV. Both peptide loaded PLA- and PLGA-NPs at 0.5 μM peptide concentration inhibited the growth of Escherichia coli O157:H7 (E. coli O157:H7), methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas. aeruginosa (P. aeruginosa). In contrast, free peptide inhibited at 10 μM but did not inhibit at 0.5 and 1 μM. These PLA- and PLGA-NPs presented <10% hemolysis indicating that they are hemocompatible and promising for delivery and protection system of GIBIM-P5S9K peptide.

Development and characterisation of HPMC films containing PLA nanoparticles loaded with green tea extract for food packaging applications

A novel active film material based on hydroxypropyl-methylcellulose (HPMC) containing poly(lactic acid) (PLA) nanoparticles (NPs) loaded with antioxidant (AO) green tea extract (GTE) was successfully developed. The PLA NPs were fabricated using an emulsification-solvent evaporation technique and the sizes were varied to enable a controlled release of the AO from the HPMC matrix. A statistical experimental design was used to optimise the synthesis of the NPs in order to obtain different sizes of nanoparticles and the loading of these into the HPMC matrix was also varied. The physico-chemical properties of the composite films were investigated and the release of the AO was confirmed by migration studies in 50% v/v ethanol/water food simulant. The AO capacity of the GTE released from the active films was studied using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical method and the results suggest that the material could potentially be used for extending the shelf-life of food products with high fat content.