Production of galactan phthalates derivatives extracted from Gracilaria birdie: Characterization, cytotoxic and antioxidant profile.

The present work explores the esterification reaction in the polysaccharide extracted from the seaweed Gracilaria birdiae and investigates its antioxidant potential. The reaction process was conducted with phthalic anhydride at different reaction times (10, 20 and 30 min), using a molar ratio of 1:2 (polymer: phthalic anhydride). Derivatives were characterized by FTIR, TGA, DSC and XRD. The biological properties of derivatives were investigated by assays of cytotoxicity and antioxidant activity (2,2-diphenyl-1-picrylhydroxyl - DPPH and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt - ABTS). The results obtained by FT-IR confirmed the chemical modification, there was a reduction related to the presence of carbonyl and hydroxyl groups when compared to the in nature polysaccharide spectrum. TGA analysis showed a change in the thermal behavior of the modified materials. X-ray diffraction, it was shown that the in nature polysaccharide appeared as an amorphous material, while the material obtained after the chemical modification process had increased crystallinity, due to the introduction of phthalate groups. For the biological assays, it was observed that the phthalate derivative was more selective than the unmodified material for the murine metastatic melanoma tumor cell line (B16F10), revealing a good antioxidant profile for DPPH and ABTS radicals.

Potential Wound Healing Effect of Gel Based on Chicha Gum, Chitosan, and Mauritia flexuosa Oil.

Wounds are considered a clinically critical issue, and effective treatment will decrease complications, prevent chronic wound formation, and allow rapid healing. The development of products based on naturally occurring materials is an efficient approach to wound healing. Natural polysaccharides can mimic the extracellular matrix and promote cell growth, thus making them attractive for wound healing. In this context, the aim of this work was to produce a gel based on chicha gum, chitosan, and Mauritia flexuosa oil (CGCHO) for wound treatment. TG and DTG analyzed the thermal behavior of the materials, and SEM investigated the surface roughness. The percentages of total phenolic compounds, flavonoids, and antioxidants were determined, presenting a value of 81.811 ± 7.257 µmol gallic acid/g Mauritia flexuosa oil, 57.915 ± 0.305 µmol quercetin/g Mauritia flexuosa oil, and 0.379 mg/mL, respectively. The anti-inflammatory was determined, presenting a value of 10.35 ± 1.46% chicha gum, 16.86 ± 1.00% Mauritia flexuosa oil, 10.17 ± 1.05% CGCHO, and 15.53 ± 0.65% chitosan, respectively. The materials were tested against Gram-negative (Klebsiella pneumoniae) and Gram-positive (Staphylococcus aureus) bacteria and a fungus (Candida albicans). The CGCHO formulation showed better antimicrobial activity against Gram-positive bacteria. In addition, an in vivo wound healing study was also performed. After 21 days of treatment, the epidermal re-epithelialization process was observed. CGCHO showed good thermal stability and roughness that can help in cell growth and promote the tissue healing process. In addition to the good results observed for the antimicrobial, antioxidant, anti-inflammatory activities and providing wound healing, they provided the necessary support for the healing process, thus representing a new approach to the wound healing process.

Nanoemulsion of cashew gum and clove essential oil (Ocimum gratissimum Linn) potentiating antioxidant and antimicrobial activity.

In this study, nanoemulsions of essential oil from Ocimumgratissimum (Linn) (EO) were produced using low and high energy techniques using cashew gum (CG) as a co-surfactant. The main constituents of the EO were determined by Gas Chromatography coupled with Mass Spectrometry (GC-MS), and their presence in the EO and in the formulations verified by Fourier Transform Infrared Spectroscopy (FTIR) and UV-visible spectrophotometry was observed the encapsulation efficiency (EE%), with colloidal stability. Nuclear magnetic resonance (NMR) was used to study cashew gum. Dynamic light scattering analysis (DLS) determined the nanoemulsion Z means, polydispersity index and the Zeta potential value, nanoparticle tracking analysis (NTA) were determined. The nanostructured EO showed better antibacterial action against the pathogenic gastroenteritis species Staphylococcus aureus, Escherichia coli and Salmonella enterica when compared to free EO. Atomic Force Microscopy (AFM) was used for morphological analysis of the nanoparticle and study of the action of the nanoemulsion through images of the cellular morphology of S. enterica. The antioxidant activity was evaluated against the ABTS radical (2,2'-azino-bis diazonium salt (3-ethylbenzothiazoline-6-sulfonic acid)). The encapsulation of EO in a nanostructured system improved its antibacterial and antioxidant activity, the low energy synthesis showed greater storage stability, remaining stable for 37 days.

Synthesis of Eudragit® L100-coated chitosan-based nanoparticles for oral enoxaparin delivery.

Enoxaparin is an effective biological molecule for prevention and treatment of coagulation disorders. However, it is poorly absorbed in the gastrointestinal tract. In this study, we developed an Eudragit® L100 coated chitosan core shell nanoparticles for enoxaparin oral delivery (Eud/CS/Enox NPs) through a completely eco-friendly method without employing any high-energy homogenizer technique and any organic solvents. Spherical nanocarriers were successfully prepared with particle size lower than 300 nm, polydispersity index about 0.12 and zeta potential higher than +25 mV, entrapment efficiency greater than 95% and the in vitro release behavior confirms the good colloidal stability and the successful Eudragit® L100 coating process demonstrated by negligible cumulative enoxaparin release (<10%) when the particles are submitted to simulated gastric fluid conditions. Finally, we demonstrated that the core-shell structure of the particle influenced the drug release mechanism of the formulations, indicating the presence of the Eudragit® L100 on the surface of the particles. These results suggested that enteric-coating approach and drug delivery nanotechnology can be successfully explored as potential tools for oral delivery of enoxaparin.

Acetylated cashew gum and fucan for incorporation of lycopene rich extract from red guava (Psidium guajava L.) in nanostructured systems: Antioxidant and antitumor capacity.

Industrial application of lycopene is limited due to its chemical instability and low bioavailability. This study proposes the development of fucan-coated acetylated cashew gum nanoparticles (NFGa) and acetylated cashew gum nanoparticles (NGa) for incorporation of the lycopene-rich extract from red guava (LEG). Size, polydispersity, zeta potential, nanoparticles concentration, encapsulation efficiency, transmission electron microscopy (TEM) and atomic force microscopy (AFM) were used to characterize nanoparticles. The antioxidant activity was determinated and cell viability was evaluated in the human breast cancer cells (MCF-7) and human keratinocytes (HaCaT) by MTT assay. The toxic effect was evaluated by hemolysis test and by Galleria mellonella model. NFGa showed higher stability than NGa, having a size of 162.10 ± 3.21 nm, polydispersity of 0.348 ± 0.019, zeta potential -30.70 ± 0.53 mV, concentration of 6.4 × 109 nanoparticles/mL and 60% LEG encapsulation. Microscopic analysis revealed a spherical and smooth shape of NFGa. NFGa showed antioxidant capacity by ABTS method and ORAC assay. The NFGa presented significant cytotoxicity against MCF-7 from the lowest concentration tested (6.25-200 µg/mL) and did not affect the cell viability of the HaCaT. NFGa showed non-toxic effect in the in vitro and in vivo models. Therefore, NFGa may have a promising application in LEG stabilization for antioxidant and antitumor purposes.

Alendronate sodium-polymeric nanoparticles display low toxicity in gastric mucosal of rats and Ofcol II cells.

The use of bisphosphonates constitutes the gold-standard therapy for the control and treatment of bone diseases. However, its long-term use may lead to gastric problems, which limits the treatment. Thus, this study aimed to formulate a nanostructured system with biodegradable polymers for the controlled release of alendronate sodium. The nanoparticles were characterized, and its gastric toxicity was investigated in rats. The synthesis process proved to be effective for encapsulating alendronate sodium, exhibiting nanoparticles with an average size of 51.02 nm and 98.5% of alendronate sodium incorporation. The release tests demonstrated a controlled release of the drug in 420 min, while the morphological analyzes showed spherical shapes and no apparent roughness. The biological tests demonstrated that the alendronate sodium nanoformulation reversed the gastric lesions, maintaining the normal levels of malondialdehyde and myeloperoxidase. Also, the encapsulated alendronate sodium showed no toxicity in murine osteoblastic cells, even at high concentrations.

Structural characterization, antifungal and cytotoxic profiles of quaternized heteropolysaccharide from Anadenanthera colubrina.

In the present work, we investigated the minimal inhibitory concentration (MIC) against fungal strains (Fonsecaea pedrosoi, Microsporum canis, Candida albicans, Cryptococcus neoformans), and cytotoxicity to normal cell lines for modified red angico gum (AG) with eterifying agent N-chloride (3-chloro-2-hydroxypropyl) trimethylammonium (CHPTAC). Quaternized ammonium groups were linked to AG backbone using N-(3-chloro-2-hydroxypropyl) trimethylammonium chloride. The chemical features of the quaternized gum derivatives (QAG) were analyzed by: FTIR, elemental analysis, Zeta potential and gel permeation chromatography. The angico quaternizated gum presented a degree of substitution (DS) of 0.22 and Zeta potential of +36.43. For the antifungal test, it was observed that unmodified gum did not inhibit fungal growth. While, QAG inhibited the growth of most fungi used in this study. By AFM technique QAG interacted with the fungal surface, altering wall roughness significantly. The probable affinity of fragments of the QAG structure for the fungal enzyme 5I33 (Adenylosuccinate synthetase) has been shown by molecular docking. Low cytotoxicity was observed for polymers (unmodified gum and QAG). The results demonstrate that the quaternized polymer of AG presented in this study is a quite promising biomaterial for biotechnological applications.

In Situ Synthesis of Silver Nanoparticles in a Hydrogel of Carboxymethyl Cellulose with Phthalated-Cashew Gum as a Promising Antibacterial and Healing Agent.

Silver nanoparticles have been shown to possess considerable antibacterial activity, but in vivo applications have been limited due to the inherent, but low, toxicity of silver. On the other hand, silver nanoparticles could provide cutaneous protection against infection, due to their ability to liberate silver ions via a slow release mechanism, and their broad-spectrum antimicrobial action. Thus, in this work, we describe the development of a carboxymethyl cellulose-based hydrogel containing silver nanoparticles. The nanoparticles were prepared in the hydrogel in situ, utilizing two variants of cashew gum as a capping agent, and sodium borohydride as the reducing agent. This gum is non-toxic and comes from a renewable natural source. The particles and gel were thoroughly characterized through using rheological measurements, UV-vis spectroscopy, nanoparticles tracking analysis, and transmission electron microscopy analysis (TEM). Antibacterial tests were carried out, confirming antimicrobial action of the silver nanoparticle-loaded gels. Furthermore, rat wound-healing models were used and demonstrated that the gels exhibited improved wound healing when compared to the base hydrogel as a control. Thus, these gels are proposed as excellent candidates for use as wound-healing treatments.