Tag Archives: propolis

Novel Formulation Based on Chitosan-Arabic Gum Nanoparticles Entrapping Propolis Extract: Production, physico-chemical and structural characterization

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By Simona Cavalu et al.

UV-Vis spectra of propolis extract and chitosan/Arabic gum
nanoparticles loaded with propolis. Copyright Simona Cavalu et al.
DLS analyses of colloidal chitosan/Arabic gum/propolis
mixture: a) Particle size distribution; b) Zeta potential. Copyright Simona Cavalu et al.
AFM images of chitosan/Arabic gum nanoparticles
entrapping propolis extract; a) 2D view; b) 3D topography; c)
Surface profile. Copyright Simona Cavalu et al.
AFM images of chitosan/Arabic gum nanoparticles
entrapping propolis extract; a) 2D view; b) 3D topography; c)
Surface profile. Copyright Simona Cavalu et al.
ATR FTIR spectra: a) raw propolis and powder chitosan/Arabic gum/propolis nanoparticles; b) powder chitosan and Arabic gum. Copyright Simona Cavalu et al.

Due to the limitation of chitosan in drug delivery systems, because of its hydrophilicity and solubility, chemical modification was performed in our study by combining with a second natural polymer, Arabic gum, in order to
improve the stability of nanoparticles. Copyright Simona Cavalu et al.

Morphological and structural characterization, using AFM, operating in tapping mode, along with the surface profile. Although the lateral dimensions are influenced by the shape of the probe, the height measurements can provide the height of nanoparticles with a high degree of accuracy and precision. However, larger particles are formed due to the aggregation during storage time. Copyright Simona Cavalu et al.

Structural characterization of polymeric powder
nanoparticles entrapping propolis was performed by ATR
FTIR spectroscopy, and compared with recorded spectrum of raw propolis, chitosan powder and Arabic gum as reference. In the same time, the
marker bands of propolis are well preserved in the polymeric mixture, indicating that the bioactive compounds are stable upon the encapsulation procedure. Copyright Simona Cavalu et al.

In this study we succeeded to prepare and characterize natural polymeric nanoparticles based on chitosan/Arabic gum, entrapping propolis extract. The physico-chemical properties of nanoparticles were assessed by UV-visible and FTIR spectroscopy, along with Dynamic Light Scattering, revealing that particle size obtained from highly dispersed mixture was in the range of 50-400 nm, with large Gaussian distribution, the maximum percentage of size distribution being at around 120 nm. In the same time,
an efficient encapsulation procedure was described using glutaraldehyde as cross-linking agent. The morpholological features of nanoparticles were emphasized by AFM microscopy, demonstrating a good correlation between
the results obtained by DLS technique. The FTIR analysis demonstrated that the marker bands of propolis are well preserved in the polymeric mixture, indicating that the bioactive compounds are stable upon the encapsulation
procedure. In our formulation, we consider that a balanced crosslinking toward electrostatic interaction was established. Propolis release from polymeric matrix was monitored in both simulated gastric acid and simulated intestinal fluids, concluding that our proposed formulation
is suitable for controlled release and pharmaceutical applications. Our results may provide a novel drug design, with improved bioavailability, stability and nutritional value of propolis bioactive compounds during processing and storage, with possible applications in food and nutraceutical industries. Copyright Simona Cavalu et al.

Full text at https://revistadechimie.ro/Articles.asp?ID=6836

The influence of propolis nanoparticles on dermal fibroblasts migration: premises for development of propolis-based collagen dermal patches

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By P. M. Pasca and Simona Cavalu

https://chalcogen.ro/929_PascaPM.pdf

Knowing the biological and pharmacological properties of propolis, the first goal of our study was to prepare and characterize a propolis nano-formulation (NPs) in order to be used for wound healing applications. The ability of propolis NPs to stimulate the migration of dermal fibroblasts in vitro was assessed by scratch test assay. The concentration of 200 μg/mL propolis NPs was found to have similar effect as the positive control. The second goal was to prepare a propolis-collagen membrane and to investigate the morphological and nanoindentation properties by AFM. The ultrastructure network of collagen fibrils was not affected by incorporation of propolis NPs, showing a nano-porous structure, favorable for soft tissue regeneration applications. Enzymatic degradation assay indicated a reduced degradation rate upon incorporation of propolis NPs in collagen matrix.

Ionotropic gelation method was applied for the preparation of propolis NPS. The nanoparticles were formed spontaneously due to ionic interaction between the protonated amine groups in chitosan and the negatively charged counter-ion TPP, being stabilized by Tween 80.

TEM image of propolis NPs; b) size distribution and c) EDX corresponding spectrum.
Copyright Simona Cavalu
Spontaneous evolution of human fibroblasts in cell culture medium, monitored at different time intervals (6, 12, 24, 48, 96 and 110 hours) until the confluence was achieved (Phase contrast image, scale bar 50 μm). Copyright Simona Cavalu
Fibroblasts migration monitored after different time intervals and wound closure under the treatment with propolis NPs at two different concentrations, compared to the positive and negative control. The initial area of the scratch (t=o) is represented by the red rectangle (Phase contrast image, scale bar 100 μm). Copyright Simona Cavalu.
The percent of restored fibroblasts monolayer upon migration of the cells into the free area, monitored during 48 h (Statistical relevance p<0.05). Copyright Simona Cavalu.
AFM images of neat collagen membrane (a,b) and collagen membrane with propolis NPs incorporated (c, d), in 3D and 2D configurations.

The tridimensional network of collagen fibrils is visible in both specimens (with or without propolis NPs incorporated) emphasizing the details of repetitive structure of the D-bands pattern of a single collagen fibril, with periodic gaps and grooves, in concordance with some previous published work [32, 33]. The periodicity of D-bands is less visible after propolis NPs incorporation. Moreover, after propolis NPs incorporation and freeze drying procedure, an obvious porous ultrastructure formation was noticed, as a result of fibers self-assembly.

Collagenase degradation test of neat collagen membrane and collagen-propolis NPs membrane (statistical relevance p<0.05). Copyright Simona Cavalu.

A collagen-based membrane was prepared and investigated by AFM in terms of morphological features and nanoindentation. The network of collagen fibrils was not affected by propolis NPs, showing a nano-porous structure, favorable for soft tissue regeneration applications. Enzymatic degradation assay indicated a reduced degradation rate upon incorporation of propolis NPs in collagen matrix. Corroborating the above mentioned results, we consider that modified-collagen membrane by adding propolis NPs in a controlled concentration, might represent a promising natural alternative to synthetic bandages for wound healing applications. Of course, further in vitro and in vivo tests are necessary to evaluate the biological performances of collagen-modified membranes, in terms of tissue adaptation and integration. (Simona Cavalu, PM Pasca, Digest Journal of Nanomaterials and Biostructures, Volume 16, Issue 3, Pages 929 – 938July-September 2021).