Charge neutralization and ß-elimination cleavage mechanism of family 42 L-rhamnose-α-1,4-D-glucuronate lyase revealed using neutron crystallography.

Gum arabic (GA) is widely used as an emulsion stabilizer and edible coating and consists of a complex carbohydrate moiety with a rhamnosyl-glucuronate group capping the non-reducing ends. Enzymes that can specifically cleave the glycosidic chains of GA and modify their properties are valuable for structural analysis and industrial application. Cryogenic X-ray crystal structure of GA-specific L-rhamnose-α-1,4-D-glucuronate lyase from Fusarium oxysporum (FoRham1), belonging to the polysaccharide lyase (PL) family 42, has been previously reported. To determine the specific reaction mechanism based on its hydrogen-containing enzyme structure, we performed joint X-ray/neutron crystallography of FoRham1. Large crystals were grown in the presence of L-rhamnose (a reaction product), and neutron and X-ray diffraction datasets were collected at room temperature at 1.80 and 1.25 Å resolutions, respectively. The active site contained L-rhamnose and acetate, the latter being a partial analog of glucuronate. Incomplete H/D exchange between Arg166 and acetate suggested that a strong salt-bridge interaction was maintained. Doubly deuterated His105 and deuterated Tyr150 supported the interaction between Arg166 and the acetate. The unique hydrogen-rich environment functions as a charge neutralizer for glucuronate and stabilizes the oxyanion intermediate. The NE2 atom of His85 was deprotonated and formed a hydrogen bond with the deuterated O1 hydroxy of L-rhamnose, indicating the function of His85 as the base/acid catalyst for bond cleavage via ß-elimination. Asp83 functions as a pivot between the two catalytic histidine residues by bridging them. This His-His-Asp structural motif is conserved in the PL 24, 25, and 42 families.

PTZ-kindled rat model; evaluation of seizure, hippocampal EGR-1, and Rev-erbα gene regulation, behavioral analysis, and antioxidant capacity of Gum Arabic.

BACKGROUND: Epilepsy is a neurological disease characterized by recurrent seizures, hyperexcitable neurons and various behavioral comorbidities. The electrical charge during seizures depletes the antioxidant defense mechanism in the epileptic brain and increases the oxidative burden. Natural antioxidant compounds are potential therapeutics in the treatment of two major pathologies of epilepsy with their anticonvulsant and anxiolytic effects and can modulate these targets. Gum Arabic is one of the natural plant polysaccharides that is non-toxic and biodegradable. METHODS AND RESULTS: A total of 30 Wistar albino male rats (8-12 weeks, 350-500 g), were randomly divided into 5 groups with 6 animals in each group: 1-Control, 2-Sham (Phosphate buffer saline (PBS)), 3-PTZ, 4-Gum Arabic, 5-PTZ + Gum Arabic. PTZ was administered i.p at 35 mg/kg/day for 11 days. After 48 h, the injection was completed with 75 mg/kg PTZ. Locomotor activity, immobilization, rearing, grooming, eating, and drinking behaviors were recorded with the LABORAS behavior system for 30 min after kindling. Animals were treated with Gum Arabic (2 mg/kg/day, oral gavage) for 10 days. At the end of the period, animal behavior was recorded again. Then the hippocampus tissues were removed. Oxidative parameters (TAS and TOS), early growth response 1 (EGR1) and nuclear receptor subfamily 1 group D member 1 (Rev-erbα) gene expressions and behaviors were analyzed. CONCLUSION: Gum Arabic increased TAS levels (P = 0.000), decreased TOS levels (P = 0.000), and thus exhibited antioxidant properties by reducing oxidative stress burden. EGR1, which was upregulated in the seizure group, was downregulated after treatment (P = 0.000), and Rev-erbα was downregulated in seizure and upregulated after treatment (P = 0.000). Gum arabic may be an antiepileptic and anxiolytic therapeutic in improving epileptic seizures by reducing oxidative stress burden through EGR1 and Rev-erbα.0.

Gamma-Irradiated Gum Arabic Grafted with 2-Hydroxyethyl Methacrylate: A Novel Superabsorbent Polymer for Controlled Folic Acid Release.

This study explores the synthesis and characterization of superabsorbent hydrogels derived from chemically modified gum Arabic, designed for controlled folic acid release. The synthesis involves a two-step process: carboxymethylation followed by grafting with 2-hydroxyethyl methacrylate via gamma irradiation. The resulting hydrogels exhibit enhanced mechanical strength and controlled diffusivity, essential for nutrient delivery systems. Key factors such as copolymer composition and irradiation dose are investigated, affecting the synthesis process. Systematic studies of swelling behaviors reveal that the hydrogel achieves a maximum swelling of 888.1% at 40 °C. The hydrogels are loaded with folic acid, and in vitro, sustained release profiles are examined under various pH conditions. The maximum release of 83.3% is observed after 24 h at pH 7.0, following a Korsmeyer-Peppas release mechanism. Different characterization techniques, confirm the successful synthesis and unique properties of the superabsorbent hydrogels. Rheological behavior analysis, scanning electron microscopy, and biocompatibility assessments provide a comprehensive understanding of the hydrogel structures. Gamma irradiation ensures a homogeneous network structure, crucial for optimal swelling behavior and mechanical properties. This research highlights the potential of eco-friendly biopolymer hydrogels in precise drug delivery applications, leveraging the safety and process control benefits of gamma irradiation.

Selenized lactic acid bacteria microencapsulated by spray drying: A promising strategy for beef cattle feed supplementation.

This study aimed to assess the technical feasibility of incorporating selenized Lactobacillus spp. microencapsulated via spray drying into cattle feed. Gum Arabic and maltodextrin were used as encapsulating agents. The encapsulation process was carried out with a drying air flow rate of 1.75 m3/min, inlet air temperature of 90°C, and outlet air temperature of 75°C. The viability of the encapsulated microorganisms and the technological characteristics of the obtained microparticles were evaluated. Microorganisms were incorporated into beef cattle feed to supplement their diet with up to 0.3 mg of Se per kilogram of feed. The encapsulated particles, consisting of a 50/50 ratio of gum Arabic/maltodextrin at a 1:20 proportion of selenized biomass to encapsulant mixture, exhibited superior technical viability for application in beef cattle feed. Supplemented feeds displayed suitable moisture, water activity, and hygroscopicity values, ensuring the preservation of viable microorganisms for up to 5 months of storage, with an approximate count of 4.5 log CFU/g. Therefore, supplementing beef cattle feed with selenized and microencapsulated lactic acid bacteria represents a viable technological alternative, contributing to increased animal protein productivity through proper nutrition.

Gum acacia dietary fiber: Significance in immunomodulation, inflammatory diseases, and cancer.

Gum arabic/acacia (GA), derived from Acacia trees, is a versatile natural product offering a broad spectrum of applications. Its rich content of soluble dietary fibers, coupled with a low caloric profile, renders GA a valuable dietary component associated with numerous health benefits. Furthermore, its fermentation by gut microbiota yields short-chain fatty acids, renowned for their positive impact on health. Immunomodulation, a crucially regulated mechanism in the body, serves to fend off pathogenic infections by releasing pro-inflammatory cytokines. However, prolonged synthesis of these cytokines can lead to chronic inflammation, tissue damage, and potentially contribute to the development of autoimmune diseases and cancer. Hence, there is an urgent need to identify plant-based biomolecules that can effectively reduce inflammation and inhibit inflammation-induced complications or disorders. In this context, edible biomolecules like GA are gaining prominence for their noteworthy immunomodulatory properties. Therefore, in the present review we have explored the role of GA in immunomodulation, inflammation, and inflammation-associated metabolic diseases, and cancer.

Improving Water-Based Drilling Mud Performance Using Biopolymer Gum: Integrating Experimental and Machine Learning Techniques.

Drilling through shale formations can be expensive and time-consuming due to the instability of the wellbore. Further, there is a need to develop inhibitors that are environmentally friendly. Our study discovered a cost-effective solution to this problem using Gum Arabic (ArG). We evaluated the inhibition potential of an ArG clay swelling inhibitor and fluid loss controller in water-based mud (WBM) by conducting a linear swelling test, capillary suction timer test, and zeta potential, fluid loss, and rheology tests. Our results displayed a significant reduction in linear swelling of bentonite clay (Na-Ben) by up to 36.1% at a concentration of 1.0 wt. % ArG. The capillary suction timer (CST) showed that capillary suction time also increased with the increase in the concentration of ArG, which indicates the fluid-loss-controlling potential of ArG. Adding ArG to the drilling mud prominently decreased fluid loss by up to 50%. Further, ArG reduced the shear stresses of the base mud, showing its inhibition and friction-reducing effect. These findings suggest that ArG is a strong candidate for an alternate green swelling inhibitor and fluid loss controller in WBM. Introducing this new green additive could significantly reduce non-productive time and costs associated with wellbore instability while drilling. Further, a dynamic linear swelling model, based on machine learning (ML), was created to forecast the linear swelling capacity of clay samples treated with ArG. The ML model proposed demonstrates exceptional accuracy (R2 score = 0.998 on testing) in predicting the swelling properties of ArG in drilling mud.

Effect of coating material on microencapsulated phenolic compounds extracted from agroindustrial ciriguela peel residue.

BACKGROUND: Extract of ciriguela residue was microencapsulated by spray-drying and freeze-drying using maltodextrin (M), gum arabic (GA) and their mixture (50% M; 50% GA on dry basis) as encapsulating agents. Total phenolic compounds (TPC), antioxidant activity, physicochemical properties, profile of phenolic compounds by HPLC with diode-array detection and storage stability were evaluated. RESULTS: TPC content of powders ranged from 306.9 to 451.2 mg gallic acid equivalent g-1 dry powder. The spray-dried powder prepared using GA as encapsulating agent had higher TPC content and antioxidant activity, whereas the freeze-dried powder had lower moisture and water activity. Spray-dried microcapsules had spherical shape, whereas freeze-dried products had irregular structures. The profile of phenolic compounds identified in samples was similar, with rutin (342.59 and 72.92 µg g-1 ) and quercetin (181.02 and 43.24 µg g-1 ) being the major compounds in liquid and freeze-dried extracts, respectively, whereas myricetin (97.41 µg g-1 ) was predominant in spray-dried ones. Storage stability tests carried out for 45 days at 7 or 25 °C revealed no statistically significant difference in TPC. CONCLUSION: Ciriguela residue can be considered a source of TPC and used as ingredient with good antioxidant activity in the food industry. © 2023 Society of Chemical Industry.

Effect of cevimeline and different concentration of gum arabic on parotid salivary gland function in methotrexate-induced xerostomia: a comparative study.

OBJECTIVE: This study assessed the effect of cevimeline and different concentrations of gum arabic on the parotid gland of rats being given xerostomia-inducing methotrexate. METHODS: One hundred twenty-five rats were divided into five equal groups of twenty-five each. The rats in Group I received basic diets, while those in Groups II, III, IV, and V received 20 mg/kg MTX as a single intraperitoneal dose on day one. Group III received 10 mg/kg CVM dissolved in saline orally and daily, and the other two groups received a 10% W/V aqueous suspension of GA. Therefore, Group IV received 2 ml/kg suspension orally and daily, while Group V received 3 ml/kg suspension orally and daily. After 9 days, the parotid glands were dissected carefully and prepared for hematoxylin and eosin (H&E) staining as a routine histological stain and caspase-3 and Ki67 immunohistochemical staining. Quantitative data from α-Caspase-3 staining and Ki67 staining were statistically analysed using one-way ANOVA followed by Tukey's multiple comparisons post hoc test. RESULTS: Regarding caspase-3 and Ki67 immunohistochemical staining, one-way ANOVA revealed a significant difference among the five groups. For Caspase-3, the highest mean value was for group II (54.21 ± 6.90), and the lowest mean value was for group I (15.75 ± 3.67). The other three groups had mean values of 31.09 ± 5.90, 30.76 ± 5.82, and 20.65 ± 3.47 for groups III, IV, and V, respectively. For Ki67, the highest mean value was for group I (61.70 ± 6.58), and the lowest value was for group II (18.14a ± 5.16). The other three groups had mean values of 34.4 ± 9.27, 48.03 ± 8.40, and 50.63 ± 8.27 for groups III, IV, and V, respectively. CONCLUSION: GA, rather than the normally used drug CVM, had a desirable effect on the salivary glands of patients with xerostomia.

Antibacterial biofilm efficacy of calcium hydroxide loaded on Gum Arabic nanocarrier: an in-vitro study.

BACKGROUND: An innovative intracanal medication formulation was introduced in the current study to improve the calcium hydroxide (Ca(OH)2) therapeutic capability against resistant Enterococcus faecalis (E. faecalis) biofilm. This in-vitro study aimed to prepare, characterize, and evaluate the antibacterial efficiency of Ca(OH)2 loaded on Gum Arabic (GA) nanocarrier (Ca(OH)2-GA NPs) and to compare this efficiency with conventional Ca(OH)2, Ca(OH)2 nanoparticles (NPs), GA, and GA NPs. MATERIALS AND METHODS: The prepared nanoparticle formulations for the tested medications were characterized using Transmission Electron Microscope (TEM) and Fourier-Transform Infrared Spectroscopy (FTIR). 141 human mandibular premolars were selected, and their root canals were prepared. Twenty-one roots were then sectioned into 42 tooth slices. All prepared root canals (n = 120) and teeth slices (n = 42) were divided into six groups according to the intracanal medication used. E. faecalis was inoculated in the samples for 21 days to form biofilms, and then the corresponding medications were applied for 7 days. After medication application, the residual E. faecalis bacteria were assessed using CFU, Q-PCR, and SEM. Additionally, the effect of Ca(OH)2-GA NPs on E. faecalis biofilm genes (agg, ace, and efaA) was investigated using RT-PCR. Data were statistically analyzed at a 0.05 level of significance. RESULTS: The synthesis of NPs was confirmed using TEM. The results of the FTIR proved that the Ca(OH)2 was successfully encapsulated in the GA NPs. Ca(OH)2-GA NPs caused a significant reduction in the E. faecalis biofilm gene expression when compared to the control (p < 0.001). There were significant differences in the E. faecalis CFU mean count and CT mean values between the tested groups (p < 0.001) except between the Ca(OH)2 and GA CFU mean count. Ca(OH)2-GA NPs showed the least statistical E. faecalis mean count among other groups. SEM observation showed that E. faecalis biofilm was diminished in all treatment groups, especially in the Ca(OH)2-GA NPS group when compared to the control group. CONCLUSIONS: Ca(OH)2 and GA nanoparticles demonstrate superior anti-E. faecalis activity when compared to their conventional counterparts. Ca(OH)2-GA NPs showed the best antibacterial efficacy in treating E. faecalis biofilm. The tested NP formulations could be considered as promising intracanal medications.

Physicochemical and biological properties of encapsulated Boesenbergia rotunda extract with different wall materials in enhancing antioxidant, mineralogenic and osteogenic activities of MC3T3-E1 cells.

Boesenbergia rotunda (L.) comprises bioactive compounds with biological and pharmacological properties, especially flavonoid compounds with osteoblastogenesis-stimulating potential. However, the application of B. rotunda in the food and pharmaceutical industry is restricted by its low solubility and stability. Encapsulation becomes an alternative to overcome these restrictions. The purpose study was to encapsulate B. rotunda extract by freeze-drying and to investigate the effects of different wall materials (maltodextrin (MD), gum arabic (GA), and their combination (MDGA)) and extract contents on the physicochemical, bioactive properties and in vitro enhancement of osteogenesis of MC3T3-E1 cells of the obtained encapsulates. The results revealed that encapsulated B. rotunda can reduce cytotoxicity, enhance biological activity, and maintain the stability of bioactive compounds. The MD was a good wall material for yield percentage. However, the values of moisture content Aw, and solubility among all the encapsulated powders were no significant differences, with all encapsulated powders having similar structures based on scanning electron microscopy. Fourier transform infrared spectroscopy confirmed the extract was encapsulated by the selected wall materials. Combining the MD and GA encapsulation agents afforded the best protection of the bioactive compounds, increasing EE (MDGA-7 > MDGA-5), pinostrobin content, TPC, and antioxidant activities (MDGA-5 > MDGA-7). The MDGA-5 and MDGA-7 at 10-50 µg/mL were not toxic to cells and promoted MC3T3-E1 cell viability, while also enhancing the Alkaline phosphatase activity, and promoting matrix mineralization of pre-osteoblast MC3T3-E1 cells after 21 and 28 days. This result showed that MDGA was a suitable wall material for B. rotunda encapsulations and a potential source of bioactive ingredients that could applied in food or pharmaceutical products for osteoporosis prevention.

Green synthesis of CaCO3 nanoparticles for photocatalysis and cytotoxicity.

In this study, Gum Arabic natural polymer was used to green synthesize calcium carbonate nanoparticles (CaCO3-NPs). Synthesized CaCO3-NPs were identified using various analyses such as FTIR, XRD, FESEM, EDX, and UV-Vis. The UV spectrum of nanoparticles showed an absorption band at a wavelength of 320 nm. FTIR analysis also confirmed the synthesis of nanoparticles. XRD studies showed that CaCO3-NPs have a rhombohedral crystalline structure with space group R-3c and an average size of about 42 nm. FESEM images showed that CaCO3-NPs have cubic morphology and EDX results confirmed the presence of carbon, calcium, and oxygen elements. The synthesized CaCO3-NPs showed good photocatalytic activity to methylene blue (MB) dye degradation, which percentage degradation was 93% after 120 min. Also, the cytotoxicity of CaCO3-NPs has been examined on the normal L929 and cancer CT26 cell lines and the IC50 value was about 250 µg/mL for cancer cells.

[Proposal for Guidelines on the Notation and Investigation of Scientific Names for the Source of Natural Food Additives in Japanese Standards].

The official specifications for food additives from natural sources list the species according to their scientific and Japanese names, thereby providing a unique identifier for the species. This helps to prevent the use of nonprescribed species, which might cause unexpected or unintended health hazards. However, there are cases in which the names of the source species listed in the official specifications differ from the accepted scientific names based on the latest taxonomic research. In this paper, we argue that it is more important to define scientific and Japanese names with an emphasis on traceability in order to control the range of food additive ingredients in a rational and sustainable manner. Therefore, we proposed a method for ensuring traceability as well as a specific notation procedure for scientific and Japanese names. Using this method, we examined the source species for three food additives. In some cases, the range of sources species expanded with the change in scientific names. Ensuring traceability is extremely important, but it is also necessary to confirm whether unexpected species are included when names are changed.

Effect of Gum Arabic powder on the mechanical properties of denture base acrylic.

Objective: This study aimed to improve the mechanical properties of denture base material using various concentrations of natural biopolymer, i.e., Gum Arabic (GA). Methods: This experimental study was conducted at the Dental Health Department of the College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia from May 2022 to July 2022. After obtaining exemption from the institutional review board, the powdered GA was added in ratios of weight 5, 10, and 20% to PMMA heat-cured acrylic powder to produce bar-shaped samples (65 × 10 × 30 mm3 in dimensions). While the control group was prepared as such. Micro hardness (n=10/group) and fracture toughness (n=10/group) were evaluated. One-way analysis of variance method was used to statistically analyze the results (p<0.05) using SPSS version 23. Results: Significant differences were observed for micro hardness (p<0.001) and fracture toughness (p=0.007) between the means of the different study groups. The control group exhibited the highest micro hardness (22.5±0.6 VHN) and fracture toughness (1.25±0.11 MPa.m1/2) value among the study groups. While 20 wt. % GA and 10 wt. % GA groups showed the lowest micro hardness and fracture toughness values, respectively. Conclusions: GA powder might not be an appropriate reinforcing material for denture base or the higher filler loading of GA in denture base acrylic might be detrimental to the mechanical properties.

Surface, mechanical and chemical properties of modified denture resin using natural biopolymer.

Objective: This laboratory study determined the surface, mechanical and chemical properties of polymethyl methacrylate (PMMA) denture resin reinforced with micron-sized Gum Arabic (GA) powder in different weight ratios. Methods: This laboratory study was conducted at the Dental Health Department of the College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia from November 2022 to February 2023. Three experimental denture resins were prepared by incorporating GA powder in heat-polymerized PMMA powder using different wt.% (5, 10, and 20 wt.%). While pristine PMMA served as the control group. A total of ten bar-shaped specimens with dimensions of 65 mm × 10 mm × 3.5 mm were prepared for each study group. The surface properties (micro CT and SEM evaluation), mechanical properties (Nanohardness, elastic modulus and flexural strength) and chemical properties (FTIR) were conducted. The data were statistically analyzed using the one-way analysis of variance and Tukey's post hoc tests (p<0.05). Results: The surface and bulk properties of experimental GA-reinforced PMMA resin materials deteriorated while the mechanical properties were also negatively altered using GA-based PMMA denture resin. A linear correlation was observed between weak mechanical properties and increasing wt.% of GA in denture resin. Conclusions: The incorporation of GA powder in denture resin might not be a viable option. The surface and mechanical properties of experimental PMMA composites were adversely affected compared to the control group.

Structural and functional analysis of gum arabic l-rhamnose-α-1,4-d-glucuronate lyase establishes a novel polysaccharide lyase family.

Gum arabic (GA) is widely used as an emulsion stabilizer and coating in several industrial applications, such as foods and pharmaceuticals. GA contains a complex carbohydrate moiety, and the nonreducing ends of the side chains are often capped with l-rhamnose; thus, enzymes that can remove these caps are promising tools for the structural analysis of the carbohydrates comprising GA. In this study, GA-specific l-rhamnose-α-1,4-d-glucuronate lyase from the fungus Fusarium oxysporum 12S (FoRham1) was cloned and characterized. FoRham1 showed the highest amino acid sequence similarity with enzymes belonging to the glycoside hydrolase family 145; however, the catalytic residue on the posterior pocket of the ß-propeller fold protein was not conserved. The catalytic residues of FoRham1 were instead conserved with ulvan lyases belonging to polysaccharide lyase family 24. Kinetic analysis showed that FoRham1 has the highest catalytic efficiency for the substrate α-l-rhamnose-(1→4)-d-glucuronic acid. The crystal structures of ligand-free and α-l-rhamnose-(1→4)-d-glucuronic acid -bound FoRham1 were determined, and the active site was identified on the anterior side of the ß-propeller. The three-dimensional structure of the active site and mutagenesis analysis revealed the detailed catalytic mechanism of FoRham1. Our findings offer a new enzymatic tool for the further analysis of the GA carbohydrate structure and for elucidating its physiological functions in plants. Based on these results, we renamed glycoside hydrolase family 145 as a new polysaccharide lyase family 42, in which FoRham1 is included.

Mechanism of Cooperative Degradation of Gum Arabic Arabinogalactan Protein by Bifidobacterium longum Surface Enzymes.

Gum arabic is an arabinogalactan protein (AGP) that is effective as a prebiotic for the growth of bifidobacteria in the human intestine. We recently identified a key enzyme in the glycoside hydrolase (GH) family 39, 3-O-α-d-galactosyl-α-l-arabinofuranosidase (GAfase), for the assimilation of gum arabic AGP in Bifidobacterium longum subsp. longum. The enzyme released α-d-Galp-(1→3)-l-Ara and ß-l-Arap-(1→3)-l-Ara from gum arabic AGP and facilitated the action of other enzymes for degrading the AGP backbone and modified sugar. In this study, we identified an α-l-arabinofuranosidase (BlArafE; encoded by BLLJ_1850), a multidomain enzyme with both GH43_22 and GH43_34 catalytic domains, as a critical enzyme for the degradation of modified α-l-arabinofuranosides in gum arabic AGP. Site-directed mutagenesis approaches revealed that the α1,3/α1,4-Araf double-substituted gum arabic AGP side chain was initially degraded by the GH43_22 domain and subsequently cleaved by the GH43_34 domain to release α1,3-Araf and α1,4-Araf residues, respectively. Furthermore, we revealed that a tetrasaccharide, α-l-Rhap-(1→4)-ß-d-GlcpA-(1→6)-ß-d-Galp-(1→6)-d-Gal, was a limited degradative oligosaccharide in the gum arabic AGP fermentation of B. longum subsp. longum JCM7052. The oligosaccharide was produced from gum arabic AGP by the cooperative action of the three cell surface-anchoring enzymes, GAfase, exo-ß1,3-galactanase (Bl1,3Gal), and BlArafE, on B. longum subsp. longum JCM7052. Furthermore, the tetrasaccharide was utilized by the commensal bacteria. IMPORTANCE Terminal galactose residues of the side chain of gum arabic arabinogalactan protein (AGP) are mainly substituted by α1,3/α1,4-linked Araf and ß1,6-linked α-l-Rhap-(1→4)-ß-d-GlcpA residues. This study found a multidomain BlArafE with GH43_22 and GH43_34 catalytic domains showing cooperative action for degrading α1,3/α1,4-linked Araf of the side chain of gum arabic AGP. In particular, the GH43_34 domain of BlArafE was a novel α-l-arabinofuranosidase for cleaving the α1,4-Araf linkage of terminal galactose. α-l-Rhap-(1→4)-ß-d-GlcpA-(1→6)-ß-d-Galp-(1→6)-d-Gal tetrasaccharide was released from gum arabic AGP by the cooperative action of GAfase, GH43_24 exo-ß-1,3-galactanase (Bl1,3Gal), and BlArafE and remained after B. longum subsp. longum JCM7052 culture. Furthermore, in vitro assimilation test of the remaining oligosaccharide using Bacteroides species revealed that cross-feeding may occur from bifidobacteria to other taxonomic groups in the gut.

Protein-polysaccharide interactions for the fabrication of bioactive-loaded nanocarriers: Chemical conjugates and physical complexes.

As unique biopolymeric architectures, covalently and electrostatically protein-polysaccharide (PRO-POL) systems can be utilized for bioactive delivery by virtue of their featured structures and unique physicochemical attributes. PRO-POL systems (i. e, microscopic /nano-dimensional multipolymer particles, molecularly conjugated vehicles, hydrogels/nanogels/oleogels/emulgels, biofunctional films, multilayer emulsion-based delivery systems, particles for Pickering emulsions, and multilayer coated liposomal nanocarriers) possess a number of outstanding attributes, like biocompatibility, biodegradability, and bioavailability with low toxicity that qualify them as powerful agents for the delivery of different bioactive ingredients. To take benefits from these systems, an in-depth understanding of the chemical conjugates and physical complexes of the PRO-POL systems is crucial. In this review, we offer a comprehensive study concerning the unique properties of covalently/electrostatically PRO-POL systems and introduce emerging platforms to fabricate relevant nanocarriers for encapsulation of bioactive components along with a subsequent sustained/controlled release.

A review of sugar beet pectin-stabilized emulsion: extraction, structure, interfacial self-assembly and emulsion stability.

In recent years, sugar beet pectin as a natural emulsifier has shown great potential in food and pharmaceutical fields. However, the emulsification performance depends on the molecular structure of sugar beet pectin, and the molecular structure is closely related to the extraction method. This review summarizes the extraction methods of pectin, structure characterization methods and the current research status of sugar beet pectin-stabilized emulsions. The structural characteristics of sugar beet pectin (such as degree of methylation, degree of acetylation, degree of blockiness, molecular weight, ferulic acid content, protein content, neutral sugar side chains, etc.) are of great significance to the emulsifying activity and stability of sugar beet pectin. Compared with traditional hot acid extraction method, ultrasonic-assisted extraction, microwave-assisted extraction, subcritical water-assisted extraction, induced electric field-assisted extraction and enzyme-assisted extraction can improve the yield of sugar beet pectin. At the same time, compared with harsh extraction conditions (too high temperature, too strong acidity, too long extraction time, etc.), mild extraction conditions can better preserve these emulsifying groups in sugar beet pectin molecules, which are beneficial to improve the emulsifying properties of sugar beet pectin. In addition, the interfacial self-assembly behavior of sugar beet pectin induced by the molecular structure is crucial to the long-term stability of the emulsion. This review provides a direction for extracting or modifying sugar beet pectin with specific structure and function, which is instructive for finding alternatives to gum arabic.

Broad Spectrum Anti-Bacterial Activity and Non-Selective Toxicity of Gum Arabic Silver Nanoparticles.

Silver nanoparticles (AgNPs) are the most commercialized nanomaterials and presumed to be biocompatible based on the biological effects of the bulk material. However, their physico-chemical properties differ significantly to the bulk materials and are associated with unique biological properties. The study investigated the antimicrobial and cytotoxicity effects of AgNPs synthesized using gum arabic (GA), sodium borohydride (NaBH4), and their combination as reducing agents. The AgNPs were characterized using ultraviolet-visible spectrophotometry (UV-Vis), dynamic light scattering (DLS), transmission electron microscopy (TEM), and Fourier-transform infrared spectroscopy (FT-IR). The anti-bacterial activity was assessed using agar well diffusion and microdilution assays, and the cytotoxicity effects on Caco-2, HT-29 and KMST-6 cells using MTT assay. The GA-synthesized AgNPs (GA-AgNPs) demonstrated higher bactericidal activity against all bacteria, and non-selective cytotoxicity towards normal and cancer cells. AgNPs reduced by NaBH4 (C-AgNPs) and the combination of GA and NaBH4 (GAC-AgNPs) had insignificant anti-bacterial activity and cytotoxicity at ≥50 µg/mL. The study showed that despite the notion that AgNPs are safe and biocompatible, their toxicity cannot be overruled and that their toxicity can be channeled by using biocompatible polymers, thereby providing a therapeutic window at concentrations that are least harmful to mammalian cells but toxic to bacteria.

A Review on the Main Phytoconstituents, Traditional Uses, Inventions, and Patent Literature of Gum Arabic Emphasizing Acacia seyal.

Acacia seyal is an important source of gum Arabic. The availability, traditional, medicinal, pharmaceutical, nutritional, and cosmetic applications of gum acacia have pronounced its high economic value and attracted global attention. In addition to summarizing the inventions/patents applications related to gum A. seyal, the present review highlights recent updates regarding its phytoconstituents. Traditional, cosmetic, pharmaceutical, and medicinal uses with the possible mechanism of actions have been also reviewed. The patent search revealed the identification of 30 patents/patent applications of A. seyal. The first patent related to A. seyal was published in 1892, which was related to its use in the prophylaxis/treatment of kidney and bladder affections. The use of A. seyal to treat cancer and osteoporosis has also been patented. Some inventions provided compositions and formulations containing A. seyal or its ingredients for pharmaceutical and medical applications. The inventions related to agricultural applications, food industry, cosmetics, quality control of gum Arabic, and isolation of some chemical constituents (L-rhamnose and arabinose) from A. seyal have also been summarized. The identification of only 30 patents/patent applications from 1892 to 15 November 2021 indicates a steadily growing interest and encourages developing more inventions related to A. seyal. The authors recommend exploring these opportunities for the benefit of society.