In vitro immune-depression and anti-inflammatory activities of cantharidin on gilthead seabream (Sparus aurata) leucocytes activated by λ-carrageenan

Cantharidin is a natural compound with known therapeutic applications in humans. The aim of this study was to investigate the in vitro effects of cantharidin on gilthead seabream (Sparus aurata) head kidney leucocytes (HKL) stimulated with λ-carrageenan. HKLs were incubated for 24 h with cantharidin (0, 2.5 and 5 μg mL-1) and λ-carrageenan (0 and 1000 μg mL-1). The results showed that HKL viability only decreased by 15.2% after incubated with 5 μg mL-1 of cantharidin and λ-carrageenan. Cantharidin increased the peroxidase activity of HKLs only when incubated in combination with λ-carrageenan. Besides this, cantharidin inhibited the respiratory burst and phagocytic activities. Furthermore, cantharidin induced morphological changes in HKLs (apoptotic and vacuolization signs) that were enhanced when incubated with λ-carrageenan. Considering the analysis of the selected gene expression studied in HKLs [NF-κB subunits (rela, relb, crel, nfkb1, nfkb2), proinflammatory cytokines (il1b, tnfa), anti-inflammatory cytokines (il10, tgfb) and caspases (casp1, casp3, casp8, casp9)], although λ-carrageenan up-regulated the expression of the proinflammatory gene il1b, λ-carrageenan and cantharidin down-regulated its expression in HKLs. In addition, cantharidin up-regulated casp3 and casp9 expression. The casp3 and casp9 gene expression was down-regulated while casp1 gene expression was up-regulated in HKLs incubated with both cantharidin and λ-carrageenan. All the effects of cantharidin are related to its inhibitory effect on protein phosphatases, which induce apoptosis at long exposure times, and minimize the effects of λ-carrageenan. The present results provide detailed insight into the immune-depressive and anti-inflammatory properties of cantharidin on immune cells, which could be of interest to the aquaculture sector.

Investigation of the anti-inflammatory effects of caffeic acid phenethyl ester in a model of λ-Carrageenan-induced paw edema in rats

In the present study, it is aimed to evaluate the effects of caffeic acid phenethyl ester (CAPE) against acute paw inflammation induced by carragenan (Carr) at macro and micro levels. Therefore, in this study, 1 hour after administering intraperitoneal of indomethacin (Ind) or CAPE (10 and 30 mg/kg body weight) to Sprague Dawley rats, Carr was injected intraplantarly into their right paws. The paw volumes of the rats were measured with a plethysmometer until the 4th hour. Also, X-ray and thermal camera images were taken to determine edema and temperature changes. At the end of the study, after the paw tissues and serums were taken, oxidative stress and inflammation status were determined using biochemical, molecular, and western blot techniques. In addition, lipid and protein profiles in paw tissue were determined using HPTLC and electrophoresis methods. The results depicted that a high dose of CAPE against Carr-induced inflammation may be almost as effective as Ind used as reference.

Effect of linear charge density of polysaccharides on interactions with α-amylase: Self-Assembling behavior and application in enzyme immobilization

The co-existence of polysaccharides and enzymes in the food matrix could form complexes that directly influence the catalytic efficacy of enzymes. This work investigated the self-assembly behaviors of α-amylase and charged polysaccharides and fabricated the α-amylase/polysaccharides complex coacervates. The results showed that the linear charge density of polysaccharides had a critical impact on the complex formation, structure, and enzyme protection under acidic conditions. At low pH, α-amylase formed compact and tight coacervates with the λ-carrageenan. However, α-amylase/pectin coacervates dissociated when the pH was lower than 3.0. The optimized binding ratio of α-amylase/λ-carrageenan was 12:1, and α-amylase/pectin was 4:1. Finally, the α-amylase/λ-carrageenan complex coacervates effectively immobilized the enzyme and almost 70% of enzyme activity remained in coacervates after exposure to pH3.0 for 1 h. This study demonstrates that the change in the linear charge density of polysaccharides could regulate the enzyme-catalyzed process in food processing by a simple and fine-controlled method.

Anti-inflammatory effect and potential mechanism of betulinic acid on λ-carrageenan-induced paw edema in mice

λ-Carrageenan (Carr), a seaweed polysaccharide, is used as a proinflammatory agent in research. Betulinic acid (BA), a naturally occurring pentacyclic triterpenoid, exerts immunomodulatory, antioxidant, anti-inflammatory, antitumor, anti-malarial and anti-HIV effects. The aim of this study was to investigate whether BA exerts anti-inflammatory effect against Carr-induced paw edema in mice, and how BA could mediate the expression of inflammation-associated MAPK-COX-2-PGE₂ signal pathway. BA pretreatment significantly reduced the inflammatory response to Carr-induced paw edema, especially at 4 h after injection. BA reduced the serum levels of pro-inflammatory cytokines, such as IL-1α, IL-1β, IL-5, IL-6, GM-CSF, KC, MCP-1 and PGE₂ in Carr-treated mice, and increased those of anti-inflammatory cytokines, such as IL-12. It also increased SOD, CAT and GSH-Px activities, and GSH content, and reduced MDA content in the liver of Carr-treated mice. Besides, BA reduced neutrophil infiltration in the basal and subcutaneous layers of the paw of Carr-treated mice, decreased the expression of COX-2 protein, and reduced the phosphorylation of JNK, p38 and ERK1/2. These results indicated that the protective effect of BA on Carr-induced paw edema might be due to its alleviation of inflammatory response and inhibition of oxidative stress, possibly by inhibiting MAPK-COX-2-PGE₂ signaling pathway activation.

Preparation and stability of nano-scaled gel beads of λ-carrageenan bound with ferric ions

Iron-deficiency anemia (IDA) is a major global public health problem, and the iron fortifiers in diet are clearly needed in the prevention and improvement of IDA for humans. A novel nano-scaled gel beads of λ-carrageenan (λ-car) specifically binding with ferric ions was developed to be a promising iron fortifier with no adverse organoleptic changes on food. Turbidity measurement, thermogravimetric analysis and Fourier transform infrared spectroscopy confirmed the successful chelating. The gel beads of λ-car-Fe³⁺ complex showed good dispersibility and solvent stability. The in vitro cell viability of HepG2 cells treated with λ-car-Fe³⁺ was over 75% at 5 mg/mL of ferric ions, indicating a significant cytotoxicity reduction of ferric ions. The stability of λ-car-Fe³⁺ complex powder was obviously increased against browning during 60 d storage with zein coating, which was attributed to the prevention of moisture permeation. Zein coated gel beads also performed a slow release of ferric ions in simulated gastrointestinal juices, resulting from the compact and hydrophobic zein surface delaying the dissociation of λ-car-Fe³⁺ in acidic environment. This λ-car-Fe³⁺ complex would have a great potential as a safe iron fortifier and facilitate iron supplementary with the advantage to relieve the side effects of iron ions.

Assessment of Heparanase-Mediated Angiogenesis Using Microvascular Endothelial Cells: Identification of λ-Carrageenan Derivative as a Potent Anti Angiogenic Agent

Heparanase is overexpressed by tumor cells and degrades the extracellular matrix proteoglycans through cleavage of heparan sulfates (HS), allowing pro-angiogenic factor release and thus playing a key role in tumor angiogenesis and metastasis. Here we propose new HS analogs as potent heparanase inhibitors: Heparin as a positive control, Dextran Sulfate, λ-Carrageenan, and modified forms of them obtained by depolymerization associated to glycol splitting (RD-GS). After heparanase activity assessment, 11 kDa RD-GS-λ-Carrageenan emerged as the most effective heparanase inhibitor with an IC₅₀ of 7.32 ng/mL compared to 10.7 ng/mL for the 16 kDa unfractionated heparin. The fractionated polysaccharides were then tested in a heparanase-rich medium-based in vitro model, mimicking tumor microenvironment, to determine their effect on microvascular endothelial cells (HSkMEC) angiogenesis. As a preliminary study, we identified that under hypoxic and nutrient poor conditions, MCF-7 cancer cells released much more mature heparanase in their supernatant than in normal conditions. Then a Matrigel^TM assay using HSkMEC cultured under hypoxic conditions in the presence (or not) of this heparanase-rich supernatant was realized. Adding heparanase-rich media strongly enhanced angiogenic network formation with a production of twice more pseudo-vessels than with the control. When sulfated polysaccharides were tested in this angiogenesis assay, RD-GS-λ-Carrageenan was identified as a promising anti-angiogenic agent.

Anti-Proliferative Activity of λ-Carrageenan Through the Induction of Apoptosis in Human Breast Cancer Cells

Background

Sulfated Polysaccharides (SPs) possess spectrum of pharmacological and therapeutic properties that could attributed to their origins variation, chemical structures and biological activities. Various studies have shown the impact of SPs on proliferation in different cancer cell lines.

Objectives

In this study, we have evaluated the biological effects of λ-carrageenan, a highly SP, extracted from the red seaweed Laurencia papillosa, on MDA-MB-231 cancer cell line.

Materials and Methods

MDA-MB-231 cells have treated with λ-carrageenan, the viability and apoptosis have assessed by the appropriate florescent probes on flow cytometer. The expression levels of mRNA of apoptotic genes have detected by real-time PCR analysis.

Results

Our results have indicated that the signaling pathway of λ-carrageenan inhibited the proliferation of MDA-MB-231 cells by up-regulating the pro-apoptotic genes caspase-8, caspase-9, caspase-3 which have been resulting the increased levels of active caspase-3 protein. Furthermore, This SP had that capacity to disrupt the mitochondrial function by altering the bax/bcl-2 ratio of expression which has considered an important element in apoptosis induction.

Conclusions

The presented results have signposted that λ-carrageenan was a promising bioactive polymer which could be a potential candidate in preventing or treating breast cancer.