Phthalic anhydride esterified chicha gum: characterization and antibacterial activity

Study of the antibacterial and cytotoxic activity of chitosan and its derivatives chemically modified with phthalic anhydride and ethylenediamine

The insertion of hydrophobic and hydrophilic chains in the chitosan molecule can improve its antibacterial activity, expanding its range of application in several areas of medical-pharmaceutical sciences. Thus, this work aimed to increase the antibacterial activity of chitosan through the modification reaction with phthalic anhydride (QF) and subsequent reaction with ethylenediamine (QFE). The chitosan and derivatives obtained were characterized by elemental analysis, 13C Nuclear Magnetic Resonance (13C NMR), X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetric Analysis (TG), where it was possible to prove the chemical modification. Both materials showed a greater antibacterial inhibitory effect against Gram-positive bacteria, Staphylococcus aureus, emphasizing antibacterial activity against Gram-negative bacteria, Escherichia coli, with values above 70 % of the inhibitory effect, which is a promising result. Assays with human fibroblast cells by the [3-(4,5-dimethylthiazolyl)-2,5-diphenyl tetrazolium (MTT)] bromide reduction test did not indicate toxicity in the materials. Thus, the derived materials showed promise for biomedical applications since they combined excellent antibacterial activity against gram-positive and gram-negative strains and did not show cytotoxicity.

Green hydrophobic maltodextrin nanosponges for magnetic solid-phase extraction of hypothalamic peptides from plasma samples

In this work, for the first time, magnetic-phthalated maltodextrin nanosponges (M-PAMDNSs) were synthetized and introduced as efficient and green sorbents. The integration of phthaloyl groups as hydrophobic moieties into networks of maltodextrin nanosponges provided good enrichment for hypothalamic-related peptides (HRPs). The synthesized materials were characterized by 1H nuclear magnetic resonance spectroscopy, water contact angle, attenuated total reflection-Fourier transform infrared spectroscopy, dynamic light scattering, zeta potential, pH point of zero charge, acid-base titration, field-emission scanning electron microscopy, Brunauer-Emmett-Teller, and vibrating sample magnetometer. Under the optimized conditions (sorbent amount: 5.0 mg, desorption solvent volume and type: 300 µL of methanol: H2O: trifluoroacetic acid, extraction time: 15 min, and desorption time: 10 min), the developed magnetic solid-phase extraction (MSPE) method in combination with HPLC-UV was used as a novel and sensitive analytical method for the determination of HRPs in plasma samples. The proposed MSPE-HPLC-UV method provided good linearity (1.5-500 ng mL-1 R2 ≥ 0.9988), low limits of detection (0.1-0.2 ng mL-1) and quantification (0.4-0.8 ng mL-1), desirable precision (RSD ≤ 8.8%, n ₌ 5), satisfactory enrichment factor (EFs ≥ 66.0), and well relative recoveries (92.8-108.8%). Overall, the established method effectively expanded the analytical potential of MSPE approach for the quantification of HRPs in biological samples.

Phthalic anhydride (PA): a valuable substrate in organic transformations

This review has been centralized on applications of phthalic anhydride (PA) as a valuable and significant heterocyclic substrate in two- and multicomponent organic reactions. The article has been subdivided into the following parts: (i) PA introduction by focusing on its characterization, synthesizing procedure, and multiple-aspect applications. In addition, the previous review articles based on PA have also been indicated; (ii) the applications of PA as a substrate have been subdivided into parts with a glance on the reaction components numbers; (iii) the applications of PA in esterification reactions; and (iv) some examples of PA in multistep synthesis. The review covers the corresponding literature up to the end of 2022. According to the abovementioned classifications, PA is a potent substrate to design a wide range of heterocyclic compounds that possess various kinds of properties and applications in chemistry, industry, and pharmaceuticals.

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.

Modification of chicha gum: Antibacterial activity, ex vivo mucoadhesion, antioxidant activity and cellular viability

The aim of the present work was to modify the exuded gum of Sterculia striata tree by an amination reaction. The viscosity and zero potential of the chicha gum varied as a function of pH. The modification was confirmed by X-ray diffraction (XRD), infrared spectroscopy (FTIR), size exclusion chromatography (SEC), zeta potential, thermogravimetric analysis (TG), and differential scanning calorimetry (DSC). Furthermore, the chemical modification changed the molar mass and surface charge of the chicha gum. In addition, the gums were used in tests for ex vivo mucoadhesion strength, antibacterial activity against the standard strain of Staphylococcus aureus (ATCC 25923), inhibitory activity of α-glucosidase, antioxidant capacity, and viability of Caco-2 cells. Through these tests, it was found that amination caused an increase in the mucoadhesive and inhibitory activity of chicha gum against the bacterium Staphylococcus aureus. In addition, the gums (pure and modified) showed antioxidant capacity and an inhibitory effect against the α-glucosidase enzyme and did not show cytotoxic potential.

Recent Advances and Prospects for Plant Gum-Based Drug Delivery Systems: A Comprehensive Review

This work is an effort to first introduce plant-based gums and discussing their drug delivery applications. The composition of these plant gums and their major characteristics, which make them suitable as pharmaceutical excipients are also described in detail. The various modifications methods such as physical and chemical modifications of gums and polysaccharides have been discussed along with their applications in different fields. Consequently, plant-based gums modification such as etherification and grafting is attracting much scientific attention to satisfy industrial demand. The evaluation tests to characterize gum-based drug delivery systems have been summarized. The release behavior of drug from plant-gum-based drug delivery is being discussed. Thus, this review is an attempt to critically summarize different aspect of plant-gum-based polysaccharides to be utilized in drug delivery systems having potential industrial applications.

Silva-Filho E, Estevinho LM. Antibacterial and Healing Effect of Chicha Gum Hydrogel (Sterculia striata) with Nerolidol

Chicha gum is a natural polymer obtained from the Sterculia striata plant. The hydroxyl groups of its structure have a chemical affinity to form hydrogels, which favors the association with biologically active molecules, such as nerolidol. This association improves the biological properties and allows the material to be used in drug delivery systems. Chicha gum hydrogels associated with nerolidol were produced at two concentrations: 0.01 and 0.02 g mL-1. Then, the hydrogels were characterized by thermogravimetry (TG), Fourier Transform Infrared spectroscopy (FTIR), and rheological analysis. The antibacterial activity was tested against Staphylococcus aureus and Escherichia coli. The cytotoxicity was evaluated against Artemia salina. Finally, an in vivo healing assay was carried out. The infrared characterization indicated that interactions were formed during the gel reticulation. This implies the presence of nerolidol in the regions at 3100-3550 cm-1. The rheological properties changed with an increasing concentration of nerolidol, which resulted in less viscous materials. An antibacterial 83.6% growth inhibition effect was observed using the hydrogel with 0.02 g mL-1 nerolidol. The in vivo healing assay showed the practical activity of the hydrogels in the wound treatment, as the materials promoted efficient re-epithelialization. Therefore, it was concluded that the chicha hydrogels have the potential to be used as wound-healing products.

Composition, Properties, and Utilization of Fumaric Acid Sludge By-Produced from Industrial Phthalic Anhydride Wastewater Treatment

To understand fumaric acid sludge (FAS) systematically and comprehensively and find out how to utilize it, we conducted a series of characterization analyses on FAS. Fourier transform infrared (FT-IR) Spectra shows that the main component of FAS is fumaric acids and also contains a small amount of silicate. The nuclear magnetic resonance hydrogen (¹H-NMR) spectrum also shows that fumaric acid accounted for a large proportion of FAS. The X-ray diffraction (XRD) shows that the main phase in FAS is fumaric acid, and there is also a small amount of Kaliophilite. After gas chromatography and mass spectrometry (GC-MS) and pyrolysis gas chromatography and mass spectrometry (Py-GC-MS) analysis, it indicates that the possible volatiles and pyrolysis products in FAS are fumaric acid, maleic acid, maleic anhydride, phthalic acid, etc. In the test of Liquid chromatography and mass spectrometry (LC-MS), we determined the contents of phthalic acid, fumaric acid, and maleic acid in FAS. The detailed mass content of each component in FAS is as follows: phthalic acid is about 0.10-0.15%; maleic anhydride is about 0.40-0.80%; maleic acid is about 18.40-19.0%; fumaric acid is about 55.00-56.90%; succinic anhydride is about 0.06-0.08%; acrylic acid is about 0.06-0.08%; malic acid is about 0.90-1.00%; acetic acid is about 0.10-0.20%; silicate is about 0.25-0.30%; phthalic anhydride is about 0.20-0.30%; water is about 24.30-24.80%. The filtrate loss reducer (PAAF) used in oilwell drilling fluids synthesized by FAS not only has excellent temperature and complex saline resistance, the API filtration loss (FL) was only 13.2 mL/30 min in the complex saline based mud, but is also cost-effective.

Reactivity of 4,5-Dichlorophthalic Anhydride towards Thiosemicarbazide and Amines: Synthesis, Spectroscopic Analysis, and DFT Study

The cyclic anhydrides are broadly employed in several fields, such as the chemical, plastic, agrochemical, and pharmaceutical industries. This study describes the chemical reactivity of 4,5-dichlorophthalic anhydride towards several nucleophiles, including thiosemicarbazide and different amines, to produce the carboxylic acid derivatives resulting from anhydride’s opening, namely, phthalimide and dicarboxylic acid (1–12) products. Their chemical structures are confirmed by NMR, IR and MS spectra analyses. Density–functional theory (DFT) studies are performed using (DFT/B3LYP) with the 6-311G(d, p) basis sets to recognize different chemical and physical features of the target compounds.

Recent advances of Sterculia gums uses in drug delivery systems

Trees of the genus Sterculia produce polysaccharide-rich exudates, such as karaya gum (Sterculia urens), chicha gum (Sterculia striata), and Sterculia foetida gum. These anionic biomaterials are biodegradable, with high viscosity, low toxicity, and gelling properties in aqueous media. According to these properties, they show promising applications as a polymer matrix for use in drug delivery systems. For this application, both the chemically modified and the unmodified polysaccharide are used. This review focuses on analyzing the state of the art of recent studies on the use of Sterculia gums in a variety of pharmaceutical forms, such as tablets, hydrogels, micro/nanoparticles, and mucoadhesive films. Sterculia gums-based delivery systems have potential to be explored for new drug delivery systems.

Eco-friendly synthesis of phthalate angico gum towards nanoparticles engineering using Quality by Design (QbD) approach

We developed a new hydrophobic polymer based on angico gum (AG), and we produced new nanoparticles to expand the applications of natural polysaccharides in nanomedicine. Phthalate angico gum (PAG) was characterized by ¹H NMR, FTIR, elementary analysis, solubility, XRD, and TG. PAG was a hydrophobic and semi-crystalline material, a relevant characteristic for drug delivery system applications. As a proof of concept, nevirapine (NVP) was selected for nanoparticles development. Plackett-Burman's experimental design was used to understand the influence of several factors in nanoparticles production. PAG proved to be a versatile material for producing nanoparticles with different characteristics. Optimized nanoparticles were produced using desirability parameters. NVP-loaded PAG nanoparticles formulation showed 202.1 nm of particle size, 0.23 of PDI, -17.1 of zeta potential, 69.8 of encapsulation efficiency, and promoted modified drug release for 8 h. Here we show that PAG presents as a promising biopolymer for drug delivery systems.