Cherry Extract from Prunus avium L. to Improve the Resistance of Endothelial Cells to Oxidative Stress: Mucoadhesive Chitosan vs. Poly(lactic-co-glycolic acid) Nanoparticles.

Polyphenolic compounds contained in cherry extract (CE) are well known for their antioxidant and anti-inflammatory properties. Unfortunately, most of these natural compounds have low oral bioavailability, reducing their widespread use. Here, different concentrations of polyphenol-rich CE from Tuscany (Italy), encapsulated in poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs), were compared with those encapsulated in two NP types, different from each other in terms of mucoadhesivity, obtained with chitosan derivatives (Ch-der), regarding CE gastrointestinal (GI) permeability and protective effect on oxidative stress. Different NP systems were physico-chemically characterized, and the antioxidant GI permeability was evaluated in a triple-cell co-culture model (Caco-2/HT29-MTX/Raji B), resembling the intestine. PLGA NPs efficiently entrapped CE (up to 840 µg gallic acid equivalent (GAE)/mL) without altering size (210 nm), polydispersity index (0.05), or zeta potential (-10.7 mV). Such NPs promoted permeation of encapsulated CE at a CE polyphenolic concentration of at least 2 µg GAE/mL. More mucoadhesive NPs from Ch-der, coded quaternary ammonium S-protected thiolated chitosan (QA-Ch-S-pro) NP, promoted CE GI permeation of 0.5 µg GAE/mL. At higher concentrations of Ch-der polymers, the resulting NPs containing CE were toxic toward Caco-2 and HT29-MTX cells. CE protected human umbilical vein endothelial cells (HUVECs) from oxidative stress and maintained its activity when entrapped in PLGA NPs. CE encapsulated in QA-Ch-S-pro NP protected HUVECs from oxidative stress, even more effectively than non-encapsulated CE. Furthermore, mucoadhesive NPs from Ch-der were more effective antioxidant protectors than PLGA NPs, but less cytotoxic PLGA NPs could be more useful when comparatively high therapeutic antioxidant doses are needed.

Chitosan-Based Nanoparticles Containing Cherry Extract from Prunus avium L. to Improve the Resistance of Endothelial Cells to Oxidative Stress.

Cherries are known for their nutraceutical properties, in particular for their antioxidant ability due to their polyphenol content, which causes a reduction of cardiovascular disease (CVD) risk factors. However, once ingested these molecules are degraded in the Gastrointestinal (GI) tract before reaching the blood, which is the action site. The object of the present work is to evaluate the ability of cherry extract (CE), encapsulated in nanoparticles (NPs) based on different chitosan (Ch) derivatives, to promote a protective effect of human umbilical vein endothelial cells (HUVECs) involved in vascular dysfunction against oxidative stress. CE-loaded NPs based on quaternary ammonium chitosan (NP1) and an S-protected thiolated derivative thereof (NP2) were prepared. The mean particle size (NP1 344.9 ± 17.8, NP2 339.9 ± 68.2 nm), the polydispersity index, the encapsulation efficiency (NP1 78.4 ± 4.5, NP2 79.8 ± 0.6%), and the zeta potential (NP1 14.8 ± 0.3, NP2 15.8 ± 0.5 mV) did not appear to be significantly different. Both NP types improved the CE apparent permeation parameters with respect to the control. Conversely, CE-loaded NP2 protected HUVECs from oxidative stress and reduced reactive oxygen species (ROS) production more than CE-loaded NP1 and free CE. In addition to promoting HUVEC resistance, NP2 could be a useful tool to overcome the problem of cherry seasonality.

Ex Vivo and in Vivo Study of Sucrosomial® Iron Intestinal Absorption and Bioavailability.

The present study aimed to demonstrate that Sideral® RM (SRM, Sucrosomial® Raw Material Iron) is transported across the excised intestine via a biological mechanism, and to investigate the effect that this transport route may produce on oral iron absorption, which is expected to reduce the gastrointestinal (GI) side effects caused by the bioavailability of non-absorbed iron. Excised rat intestine was exposed to fluorescein isothiocyanate (FITC)-labeled SRM in Ussing chambers followed by confocal laser scanning microscopy to look for the presence of fluorescein-tagged vesicles of the FITC-labeled SRM. To identify FITC-labeled SRM internalizing cells, an immunofluorescence analysis for macrophages and M cells was performed using specific antibodies. Microscopy analysis revealed the presence of fluorescein positive particulate structures in tissues treated with FITC-labeled SRM. These structures do not disintegrate during transit, and concentrate in macrophage cells. Iron bioavailability was assessed by determining the time-course of Fe3+ plasma levels. As references, iron contents in liver, spleen, and bone marrow were determined in healthy rats treated by gavage with SRM or ferric pyrophosphate salt (FP). SRM significantly increased both area under the curve (AUC) and clearance maxima (Cmax) compared to FP, thus increasing iron bioavailability (AUCrel = 1.8). This led to increased iron availability in the bone marrow at 5 h after single dose gavage.

Sucrosomial® iron absorption studied by in vitro and ex-vivo models.

This paper presents a comparative evaluation of different oral ferric iron formulations for ability to retain Fe3+ in simulated gastric fluid (SGF), be internalized by cells lining intestinal epithelium, and cross it to reach the bloodstream. In all formulations iron was ferric pyrophosphate, the excipients were different types and fractions of lecithin plus sucrose esters of fatty acids matrix (Sideral® RM; PRT1; PRT2) or lecithin without sucrester (SUN). Dissolution kinetics of formulations in SGF was studied by USP method. The ability of the formulations to promote iron intestinal absorption was evaluated by the Caco-2 cell model, measuring cellular ferritin content, and by the excised rat intestine model, yielding apparent permeability parameters (Papp). All formulations limited iron release in SGF to ≤10%. Sideral® RM was by far the most absorbed by Caco-2, as ferritin content was in the order: Sideral® RM≫PRT2>PRT1>SUN>control. The Fe3+ crossing the intestinal barrier was in part reduced to Fe2+ by epithelial enzymes, in part it was carried by formulation rearrangement into nano-structures able to protect it from reduction and apt for internalization by epithelium cells. Papp parameters were in the order: Sideral® RM≫PRT1>PRT2>SUN=control. Relevance of transepithelial Fe2+carrier, DMT-1, to Fe3+ transport was ruled out using a DMT-1 inhibitor. In conclusion, Sideral® RM retains iron in SGF, and is the most suitable for Fe3+ internalization by Caco-2 cells, Fe3+ protection from enzymatic reduction and promotion of Fe3+ absorption across intestinal epithelium, non-mediated by DMT-1.

Delivery of natural polyphenols by polymeric nanoparticles improves the resistance of endothelial progenitor cells to oxidative stress.

PURPOSE: Bone marrow-derived endothelial progenitor cells (EPCs) circulate into peripheral blood and significantly contribute to neo-vascularisation and re-endothelialisation as part of the process of vascular repair. Several studies have reported decreased EPC number in the presence of oxidative stress. Aim of this study was to evaluate the validity of mucoadhesive polymeric nanoparticles as a delivery system of natural products able to protect EPCs from oxidative stress. METHODS: The total polyphenol content and antioxidant capacity of red grape seed extract (GSE) either pre-veraison (p-GSE) or ripe (r-GSE) were measured. Cell viability was evaluated by WST-1 assay. Nanoparticles were prepared by ionotropic crosslinking of two structurally different thiolated quaternary ammonium-chitosan conjugates. A hyaluronic acid solution, containing p-GSE or r-GSE, was added to a stirred solution of each of the two chitosan derivatives to obtain p- or r-GSE loaded nanoparticles (NP) of two types. RESULTS: Both GSE types demonstrated strong antioxidant capacity. p-GSE showed a higher content in total polyphenols compared to r-GSE. NP size was in the 310-340 nm range, with 24 h stability, and nearly 100% encapsulation efficiency for both GSE types. NP were internalized by cells to an extent related directly with their surface charge intensity. GSE-NP uptake significantly improved cell viability and resistance to oxidation. CONCLUSIONS: Nanotechnology has a great potential in nutraceutical delivery. The present results suggest that NP is a highly promising polyphenol carrier system particularly useful to protect EPCs from oxidative stress, thus improving their survival.