Biological Activity and Pharmacological Application of Pectic Polysaccharides: A Review

Anti-melanogenesis effect from Wampee fruit pectin via α-MSH/TRY pathway in A375 cells

Background

Polysaccharides from wampee have been reported to process various biological activities, while the relationship between structure and bioactivities has been barely addressed. Pectin, an abundant water-soluble polysaccharide in wampee, showed significant antioxidant activity, which was associated with the anti-melanogenic activity. Therefore, this study investigated the physicochemical characteristics and the anti-melanogenesis effect of pectin extracted from wampee fruit in A375 cells.

Methods

The physicochemical characterization of pectin from wampee fruit was investigated by gel chromatography (GCP), FT-IR spectroscopy, and NMR spectroscopy methods. The anti-melanogenesis effects and mechanism were evaluated by mushroom tyrosine enzyme and human melanin cell model in vitro.

Results

The results showed that a molecular weight of 5.271 × 10⁵ Da wampee fruit pectin (WFP) were mainly composed of mannose (Man), ribose (Rib), rhamnose (Rha), glucuronic acid (Glc A), glucose (Glc), galacturonic acid (Gal A), galactose (Gal), and arabinose (Ara), which linked with →4)-β-D-Galp-(1 → units. The current study revealed that WFP could significantly suppress mushroom TRY activity in vitro. Furtherly, WFP significantly reduced intracellular and extracellular melanin formation in A375 melanoma cells depending on the presence of alpha-melanocyte stimulating hormone (α-MSH). TRY activity was only inhibited in α-MSH treated A375 cells. Western blot analysis demonstrated that WFP reverse α-MSH induced melanogenesis in A375 melanoma cells, including in down-regulated TRY, TYRP-1, TYRP-2, MITF and CREB expressions.

Conclusion

These results indicated that WFP could inhibit α-MSH induced melanogenesis in A375 melanoma cells via α-MSH/TRY pathway. In conclusion, these data provided a new perspective to annotate WFP anti-melanogenesis activity mechanism.

Effect of Cross-Linking Cations on In Vitro Biocompatibility of Apple Pectin Gel Beads

The study aimed to compare the in vitro biocompatibility of pectin gels formed by different cross-linking cations. Hydrogel beads named CaPG, ZnPG, FePG, and AlPG were prepared from 4% solutions of apple pectin using ionotropic gelling with CaCl2, ZnCl2, FeCl3, and AlCl3, respectively. Cations influenced the gel strength of the wet gel beads in the following order (least strong) Ca2+ < Zn2+ < Fe3+~Al3+ (most strong). The swelling degree of the CaPG beads after 24 h of incubation in the RPMI-1640 medium was 104%, whereas the ZnPG, FePG, and AlPG beads swelled by 76, 108, and 134%, respectively. The strength of the pectin gel decreased significantly after incubation in the RPMI-1640 medium for 24 h, regardless of the cross-linking cation, although the FePG beads remained the strongest. All the pectin beads adsorbed serum proteins to a low degree, however the serum protein adsorption by the ZnPG and FePG beads (1.46 ± 0.87 and 1.35 ± 0.19 µg/mm2) was more than the CaPG and AlPG beads (0.31 ± 0.36 and 0.44 ± 0.25 µg/mm2). All the pectin beads reduced the production of TNF-α and IL-10 by hPBMCs in response to LPS stimulation. The IL-1β response of cells to LPS was significantly reduced by the CaPG, ZnPG, and FePG beads, whereas the AlPG beads enhanced it twofold. The CaPG, FePG, and AlPG beads had no cytotoxicity. The viability of hPBMCs and human fibroblasts incubated with ZnPG beads was 5.3 and 7.2%, respectively. Thus, the use of different cross-linking cations changed the properties of the pectin gel, which is important for biocompatibility.

Polysaccharides of Salsola passerina: Extraction, Structural Characterization and Antioxidant Activity

The above-ground part of the Salsola passerine was found to contain ~13% (w/w) of polysaccharides extractable with water and aqueous solutions of ammonium oxalate and sodium carbonate. The fractions extracted with aqueous sodium carbonate solutions had the highest yield. The polysaccharides of majority fractions are characterized by similar monosaccharide composition; namely, galacturonic acid and arabinose residues are the principal components of their carbohydrate chains. The present study focused on the determination of antioxidant activity of the extracted polysaccharide fractions and elucidation of the structure of polysaccharides using nuclear magnetic resonance (NMR) spectroscopy. Homogalacturonan (HG), consisting of 1,4-linked residues of α-D-galactopyranosyluronic acid (GalpA), rhamnogalacturonan-I (RG-I), which contains a diglycosyl repeating unit with a strictly alternating sequence of 1,4-linked D-GalpA and 1,2-linked L-rhamnopyranose (Rhap) residues in the backbone, and arabinan, were identified as the structural units of the obtained polysaccharides. HMBC spectra showed that arabinan consisted of alternating regions formed by 3,5-substituted and 1,5-linked arabinofuranose residues, but there was no alternation of these residues in the arabinan structure. Polysaccharide fractions scavenged the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical at 0.2-1.8 mg/mL. The correlation analysis showed that the DPPH scavenging activity of polysaccharide fractions was associated with the content of phenolic compounds (PCs).

New findings on acid-extractable pectins from soy hull

Soy hull has been considered a potential source of commercial pectin. The aim of the present study was to investigate its real potential as a source of pectin. Soy hull (sample 1) was extracted with 0.1 M HCl, for 45 min, at 90 °C (fraction A), conditions previously reported to result in yields and GalA in the range of commercial pectins. The extraction resulted in low uronic acid content (UA 39 %) and lower yield. Similar values were obtained using harsher conditions (boiling 0.14 M HNO₃ for 30 min and 60 min - Fractions B and C, respectively). HSQC-NMR confirmed the coextraction of galactomannans. Considering the unexpected results, three other soy hull samples (2, 3 and 4) were used for extraction. The yields and UA were in the range of 10-13 % and 26-48 %, respectively, also below published data. Prior removal of galactomannan by water extraction increased the UA content to 62 % and gave rise to a pectin with a degree of methyl-esterification (DM) of 29 %. The pectin had remarkable amount of rhamnogalacturonan I and xylogalacturonan and did not form gel with calcium. The findings using four different commercial samples did not support previously published data and demonstrated that soy hull is not suitable as a raw material for production of food grade pectins by conventional extraction.

Potential of pectin for biomedical applications: a comprehensive review

Pectin is a polysaccharide extracted from various plants, such as apples, oranges, lemons, and it possesses some beneficial effects on human health, including being hypoglycemic and hypocholesterolemic. Therefore, pectin is used in various pharmaceutical and biomedical applications. Meanwhile, its low mechanical strength and fast degradation rate limit its usage as drug delivery devices and tissue engineering scaffolds. To enhance these properties, it can be modified or combined with other organic molecules or polymers and/or inorganic compounds. These materials can be prepared as nano sized drug carriers in the form of spheres, capsules, hydrogels, self assamled micelles, etc., for treatment purposes (mostly cancer). Different composites or blends of pectin can also be produced as membranes, sponges, hydrogels, or 3D printed matrices for tissue regeneration applications. This review is concentrated on the properties of pectin based materials and focus especially on the utilization of these materials as drug carriers and tissue engineering scaffolds, including 3D printed and 3D bioprinted systems covering the studies in the last decade and especially in the last 5 years.

Influence of glycosyl composition on the immunological activity of pectin and pectin-derived oligosaccharide

Factors causing differences in immune activities between pectin and pectin-derived oligosaccharides have not been fully studied. In this article, four samples with different molecular weights and monosaccharide compositions, including polygalacturonic acid (poly-GA) and its oligosaccharide (oligo-GA), navel orange peel pectin (NP) and its oligosaccharide (oligo-NP), were used to compare their immunomodulatory properties on RAW264.7 cells. All samples had nontoxic effect on cells, oligo-GA and oligo-NP could increase the production of nitric oxide and cytokines to a much higher level than poly-GA and NP. The findings revealed that reducing the molecular weight and preserving the branched regions of pectin-derived samples could improve their immune-enhancing effects on macrophages. Interestingly, the addition of TAK-242 (TLR4 inhibitor) also demonstrated that the tested pectin oligosaccharides could stimulate the activation of macrophages through TLR4 signaling pathway. These results confirmed the potential value of pectin oligosaccharides, and provided theoretical support for their application in the pharmaceutical industry.

Investigation of bioactivity of unsaturated oligo‑galacturonic acids produced from apple waste by Alcaligenes faecalis AGS3 and Paenibacillus polymyxa S4 Pectinases

Pectin is one of the main structural components in fruits and an indigestible fiber made of D-galacturonic acid units with α (1-4) linkage. This study investigates the microbial degradation of pectin in apple waste and the production of bioactive compounds. Firstly, pectin-degrading bacteria were isolated and identified, then pectinolytic activity was assessed by DNS. The products were evaluated by TLC and LC-MS-ESI. The antioxidative effects were investigated using DPPH and anti-cancer effects and cytotoxicity were analyzed by MTT and flow cytometry. In this study two new bacterial isolates, Alcaligenes faecalis AGS3 and Paenibacillus polymyxa S4 with the pectinolytic enzyme were introduced. Structure analysis showed that the products of enzymatic degradation include unsaturated mono, di, tri, and penta galacturonic acids with 74% and 69% RSA at 40 mg/mL for A. faecalis and P. polymyxa S4, respectively. The results of anti-tumor properties on MCF-7 cells by MTT assay, for products of AGS3 and S4 at 40 mg/mL after 48 h, showed 7% and 9% survival, respectively. In the flow cytometric assessment, the compounds of AGS3 at 40 mg/mL were 100% lethal in 48 h and regarding S4 isolate caused 98% death. Cytotoxicity evaluation on L-929 cells showed no significant toxicity on living cells.

The comparison of preliminary structure and intestinal anti-inflammatory and anti-oxidative activities of polysaccharides from different root parts of Angelica sinensis (Oliv.) Diels

ETHNOPHARMACOLOGICAL RELEVANCE

The root of Angelica sinensis, has been commonly used in gynecology for centuries, and is normally applied divided into different parts in various clinical applications. At present, the majority of existing studies focus on the volatile oil and ferulic acid extracted from different parts of A. sinensis, but there is a dearth of scientific information on its water-soluble polysaccharides.

AIM OF THE STUDY

The structures of polysaccharides from plants, have been reported contributing to multiple pharmacological activities such as anti-oxidative, anti-inflammatory, anti-tumor and liver protection. Therefore, the focus of this study was on its anti-oxidative and anti-inflammatory activities in vitro, which would be based on the various polysaccharides with distinct structures obtained from different parts of the A. sinensis root.

MATERIALS AND METHODS

Four parts of A. sinensis root were separated according to the Chinese Pharmacopoeia: head, body, tail and whole body. Crude polysaccharides were obtained by water extraction and ethanol precipitation method, and were further fractionated by DEAE Sepharose chromatographic column and gel filtration. The comparison of ASPs from different root parts were performed, including chemical compositions determined by colorimetric analysis, monosaccharide compositions measured by high performance liquid chromatography (HPLC), glycosidic linkage units determined by methylation and gas chromatography-mass spectrometry (GC-MS), organic functional groups determined by FT-IR, molecular weight (Mw) demarcated by gel permeation chromatography, and the viscosities and solubilities were measured according to method published in the previous report with minor modification. In vitro biological activities of APSs were compared on lipopolysaccharide (LPS)-induced inflammatory and oxidative stress models on IPEC-J2 cells.

RESULTS

Four purified polysaccharides, ASP-H-AP, ASP-B-AP, ASP-T-AP and ASP-Hb-AP from the root of A. sinensis, were obtained, and consisted of various contents of protein and the polyphenol. They were possibly pectic polysaccharides with a long homogalacturonan region as the main backbone and ramified with rhamnogalacturonan I region, but they were differed by subregions and the relative contents of glycosidic units. The Mw of four pectic polysaccharides were ranged from 67.9-267.7 kDa. The infrared spectrum also showed that the four polysaccharide fractions contained the characteristic peaks of polysaccharides. Their distinct primary structure could lead to a variety of biological activities. In vitro biological assays suggested that four polysaccharide fractions can protect IPEC-J2 cells against the LPS-induced inflammation by down-regulating inflammation factors and related genes on IPEC-J2 cells. These polysaccharides also could alleviate oxidative stress on IPEC-J2 cells by up-regulating the gene and protein expressions of antioxidant enzymes. It was concluded that ASP-H-AP possessed better anti-inflammatory and anti-oxidative effects, while those of ASP-T-AP was relatively poor among the four polysaccharide fractions.

CONCLUSION

All results indicated that the structure of pectic polysaccharides from different root parts of A. sinensis differed, which lead to their distinct anti-inflammatory and anti-oxidative activities. This may also be one of the factors why different parts of A. sinensis showed various pharmacological activities and applied independently in traditional use. In addition, it would be valuable for further studies on structure-activity relationship of polysaccharides obtained by different root parts of A. sinensis.

Structure and bioactivity of apple pectin isolated with arabinanase and mannanase

It was assumed that, high purity endo-arabinanase and endo-mannanase could be useful in the isolation of pectin of enhanced health-promoting potential. Extraction was carried out with 50 U of enzymes per gram of apple pomace at 40 °C, obtaining up to 22% increase in effectiveness, as compared to the acid extraction. The pectins, despite their high M_w, were homogeneous and contained more galacturonic acid, rhamnose, galactose, fucose, and ferulic acid than the conventional product, thanks to which they quenched free radicals up to five times more efficiently. Compared with pectin with recognised anticancer and prebiotic activity, they had a significantly greater ability to inhibit proliferation and migration of HT-29 and B16F10 cells. They were also more effective in preventing the adhesion of E. coli and S. typhimurium to enterocytes. Endo-arabinanase- and endo-mannanase-assisted extraction is an effective method of obtaining pectins with enhanced antiradical, anticancer and prebiotic potential.

Pharmaceutical and drug delivery applications of pectin and its modified nanocomposites

Due to their natural availability, biocompatibility, biodegradability, nontoxicity, flexibility, as well as improved structural and functional characteristics, pectin and pectin-based nanocomposites have become an interesting area of numerous researchers. Pectin is a polysaccharide that comes from plants and is used in a variety of products. The significance of pectin polysaccharide and its modified nanocomposites in a number of applications has been shown in numerous reviews. On their uses in pharmaceutical and medication delivery, there are, however, few review publications. The majority of papers on pectin polysaccharide do not structure their explanations of drug distribution and medicinal application. The biological application of pectin nanocomposite is also explained in this review, along with a recent publication. As a result, the goal of this review was in-depth analysis to summarize biological application of pectin and its modified nanocomposites. Due to their exceptional physicochemical and biological characteristics, pectin and its nanocomposites are remarkable materials for medicinal applications. In addition to enhancing the immune system, controlling blood cholesterol, and other things, they have been shown to have anticancer, antidiabetic, antioxidant, anti-inflammatory, immunomodulatory, and antibacterial properties. Because of their biocompatibility and properties that allow for regulated release, they have also received a lot of interest as drug carriers in targeted drug delivery systems. They have been used to administer medications to treat cancer, inflammation, pain, Alzheimer's, bacteria, and relax muscles. This review found that pectin and its derivatives have better drug delivery efficiency and are viable candidates for a wide range of medicinal applications. It has been advised to conduct further research on the subject of toxicity in order to produce commercial formulations that can serve as both therapeutic agents and drug carriers.

Biological activity of pectic polysaccharides investigated through biomembrane models formed at the air-water interface

Pectin, a polysaccharide with potential bioactivity, was inserted in the aqueous subphase of monolayers of the selected lipids DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) and DPPE (1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine), representing mammalian and bacterial membranes, respectively. Pectin condensed both monolayers but made the DPPC monolayer more fluid, while for DPPE, it made its monolayer more rigid, as detected with dynamic interfacial rheology. Complementary data using surface potential, infrared spectroscopy, and Brewster angle microscopy also showed distinctive effects of pectin on DPPE and DPPC. We believe these data can be correlated with the action of this polysaccharide with biological lipidic surfaces with different polar heads, which may be relevant, generally speaking, to understanding the molecular mechanism of this bioactive compound for pharmaceutical purposes.

Investigation of Hydrogel Sheets Based on Highly Esterified Pectin

The report describes the features of physical and mechanical properties and absorption capacity of hydrogels based on highly esterified pectin. Experimental data showed the correlation between these values. Also, an attempt is made to explain the obtained dependencies via the hydrogel morphology and the mechanism of its formation.

The Use of Endo-Cellulase and Endo-Xylanase for the Extraction of Apple Pectins as Factors Modifying Their Anticancer Properties and Affecting Their Synergy with the Active Form of Irinotecan

Pectin constitutes an essential component of dietary fiber. Modified pectins from various sources possess potent anticancer and immunomodulatory activities. In this study, two pectins isolated from apple pomace by Trichoderma enzyme treatment, PX (with endo-xylanase) and PCX (with both endo-cellulase and endo-xylanase), were studied in colon cancer cell lines (HCT 116, Caco-2, and HT-29). Both pectins reduced colon cancer cell viability, induced apoptosis, and increased intracellular amounts of reactive oxygen species. Additionally, synergy between pectin and an active form of irinotecan, SN-38, in all aspects mentioned above, was discovered. This drug is a common component of cytotoxic combinations recommended as treatment for colon cancer patients. PX and PCX demonstrated significant anti-inflammatory activity in lipopolysaccharide-stimulated cells. Interaction of apple pectins with galectin-3 and Toll-like Receptor 4 (TLR4) was suggested to be responsible for their anticancer and anti-inflammatory effect. Since PCX was more active than PX in almost all experiments, the role of the enzyme used to obtain the pectin for its biological activity was discussed. It was concluded that co-operation between both enzymes was needed to obtain the molecule of the most beneficial properties. The low molecular mass of PCX together with a high proportion of rhamnogalacturonan I (RG I) regions seemed to be crucial for its superior activity.

Optical and Mechanical Properties of Self-Repairing Pectin Biopolymers

Pectin’s unique physicochemical properties have been linked to a variety of reparative and regenerative processes in nature. To investigate the effect of water on pectin repair, we used a 5 mm stainless-steel uniaxial load to fracture glass phase pectin films. The fractured gel phase films were placed on a 1.5–1.8 mm thick layer of water and incubated for 8 h at room temperature and ambient humidity. There was no immersion or agitation. The repaired pectin film was subsequently assessed for its optical and mechanical properties. Light microscopy demonstrated repair of the detectable fracture area and restoration of the films’ optical properties. The burst strength of the repaired film declined to 55% of the original film. However, its resilience was restored to 87% of the original film. Finally, a comparison of the initial and post-repair fracture patterns demonstrated no recurrent fissures in the repaired glass phase films. The water-induced repair of the pectin film was superior to the optical and mechanical properties of the repaired films composed of nanocellulose fibers, sodium hyaluronate, and oxidized cellulose. We conclude that the unique physicochemical properties of pectin facilitate the water-induced self-repair of fractured pectin films.

Swelling, Protein Adsorption, and Biocompatibility In Vitro of Gel Beads Prepared from Pectin of Hogweed Heracleum sosnówskyi Manden in Comparison with Gel Beads from Apple Pectin

The study aims to develop gel beads with improved functional properties and biocompatibility from hogweed (HS) pectin. HS4 and AP4 gel beads were prepared from the HS pectin and apple pectin (AP) using gelling with calcium ions. HS4 and AP4 gel beads swelled in PBS in dependence on pH. The swelling degree of HS4 and AP4 gel beads was 191 and 136%, respectively, in PBS at pH 7.4. The hardness of HS4 and AP4 gel beads reduced 8.2 and 60 times, respectively, compared with the initial value after 24 h incubation. Both pectin gel beads swelled less in Hanks’ solution than in PBS and swelled less in Hanks’ solution containing peritoneal macrophages than in cell-free Hanks’ solution. Serum protein adsorption by HS4 and AP4 gel beads was 118 ± 44 and 196 ± 68 μg/cm² after 24 h of incubation. Both pectin gel beads demonstrated low rates of hemolysis and complement activation. However, HS4 gel beads inhibited the LPS-stimulated secretion of TNF-α and the expression of TLR4 and NF-κB by macrophages, whereas AP4 gel beads stimulated the inflammatory response of macrophages. HS4 gel beads adsorbed 1.3 times more LPS and adhered to 1.6 times more macrophages than AP4 gel beads. Thus, HS pectin gel has advantages over AP gel concerning swelling behavior, protein adsorption, and biocompatibility.

Progress in valorisation of agriculture, aquaculture and shellfish biomass into biochemicals and biomaterials towards sustainable bioeconomy

The recurrent environmental and economic issues associated with the diminution of fossil fuels are the main impetus towards the conversion of agriculture, aquaculture and shellfish biomass and the wastes into alternative commodities in a sustainable approach. In this review, the recent progress on recovering and processing these biomass and waste feedstocks to produce a variety of value-added products via various valorisation technologies, including hydrolysis, extraction, pyrolysis, and chemical modifications are presented, analysed, and discussed. These technologies have gained widespread attention among researchers, industrialists and decision makers alike to provide markets with bio-based chemicals and materials at viable prices, leading to less emissions of CO₂ and sustainable management of these resources. In order to echo the thriving research, development and innovation, bioresources and biomass from various origins were reviewed including agro-industrial, herbaceous, aquaculture, shellfish bioresources and microorganisms that possess a high content of starch, cellulose, lignin, lipid and chitin. Additionally, a variety of technologies and processes enabling the conversion of such highly available bioresources is thoroughly analysed, with a special focus on recent studies on designing, optimising and even innovating new processes to produce biochemicals and biomaterials. Despite all these efforts, there is still a need to determine the more cost-effective and efficient technologies to produce bio-based commodities.

Resveratrol-loaded chitosan-pectin core-shell nanoparticles as novel drug delivery vehicle for sustained release and improved antioxidant activities

Resveratrol, chemically known as 3,5,4'-trihydroxy-trans-stilbene, is a natural polyphenol with promising multi-targeted health benefits. The optimal therapeutic uses of resveratrol are limited due to its poor solubility, rapid metabolism and low bioavailability. To address the issues, we have encapsulated resveratrol inside the nanosized core made of chitosan and coated this core with pectin-shell in order to fabricate a drug delivery vehicle which can entrap resveratrol for a longer period of time. The core-shell nanoparticles fabricated in this way were characterized with the help of Fourier transform infrared spectrometer, field-emission scanning electron microscope, field-emission transmission electron microscopy/selected area electron diffraction, high-resolution transmission electron microscope, dynamic light scattering and zeta potential measurements. In vitro drug release study showed the ability of the core-shell nanoparticles to provide sustained release of resveratrol for almost 30 h. The release efficiency of the drug was found to be pH dependent, and a sequential control over drug release can be obtained by varying the shell thickness. The resveratrol encapsulated in a nanocarrier was found to have a better in vitro antioxidant activity than free resveratrol as determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method. This work finally offers a novel nano-based drug delivery system.

Characterization and Biocompatibility Properties In Vitro of Gel Beads Based on the Pectin and κ-Carrageenan

This study aimed to investigate the influence of kappa (κ)-carrageenan on the initial stages of the foreign body response against pectin gel. Pectin-carrageenan (P-Car) gel beads were prepared from the apple pectin and κ-carrageenan using gelling with calcium ions. The inclusion of 0.5% κ-carrageenan (Car0.5) in the 1.5 (P1.5) and 2% pectin (P2) gel formulations decreased the gel strength by 2.5 times. Car0.5 was found to increase the swelling of P2 gel beads in the cell culture medium. P2 gel beads adsorbed 30–42 mg/g of bovine serum albumin (BSA) depending on pH. P2-Car0.2, P2-Car0.5, and P1.5-Car0.5 beads reduced BSA adsorption by 3.1, 5.2, and 4.0 times compared to P2 beads, respectively, at pH 7. The P1.5-Car0.5 beads activated complement and induced the haemolysis less than gel beads of pure pectin. Moreover, P1.5-Car0.5 gel beads allowed less adhesion of mouse peritoneal macrophages, TNF-α production, and NF-κB activation than the pure pectin gel beads. There were no differences in TLR4 and ICAM-1 levels in macrophages treated with P and P-Car gel beads. P2-Car0.5 hydrogel demonstrated lower adhesion to serous membrane than P2 hydrogel. Thus, the data obtained indicate that the inclusion of κ-carrageenan in the apple pectin gel improves its biocompatibility.

Green synthesis of metallic nanoparticles using pectin as a reducing agent: a systematic review of the biological activities

CONTEXT

Pectin is a plant heteropolysaccharide that is biocompatible and biodegradable, enabling it to be an excellent reducing agent (green synthesis) for metallic nanoparticles (MNPs). Nevertheless, in the biological industry, pectin has been left behind in synthesising MNPs, for no known reason.

OBJECTIVE

To systematically review the biological activities of pectin synthesised MNPs (Pe-MNPs).

METHODS

The databases Springer Link, Scopus, ScienceDirect, Google Scholar, PubMed, Mendeley, and ResearchGate were systematically searched from the date of their inception until 10^th February 2020. Pectin, green synthesis, metallic nanoparticles, reducing agent and biological activities were among the key terms searched. The data extraction was focussed on the biological activities of Pe-MNPs and reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations for systematic reviews.

RESULTS

A total of 15 studies outlined 7 biological activities of Pe-MNPs in the only three metals that have been explored, namely silver (Ag), gold (Au) and cerium oxide (CeO₂). The activities reported from the in vitro and in vivo studies were antimicrobial (9 studies), anticancer (2 studies), drug carrier (3 studies), non-toxic (4 studies), antioxidant (2 studies), wound healing (1 study) and anti-inflammation (1 study).

CONCLUSIONS

This systematic review demonstrates the current state of the art of Pe-MNPs biological activities, suggesting that Ag and Au have potent antibacterial and anticancer/chemotherapeutic drug carrier activity, respectively. Further in vitro, in vivo, and clinical research is crucial for a better understanding of the pharmacological potential of pectin synthesised MNPs.

Isolation, Chemical Characterization and Antioxidant Activity of Pectic Polysaccharides of Fireweed (Epilobium angustifolium L.)

The aim of this study was to isolate pectins with antioxidant activity from the leaves of Epilobium angustifolium L. Two pectins, EA-4.0 and EA-0.8, with galacturonic acid contents of 88 and 91% were isolated from the leaves of E. angustifolium L. by the treatment of plant raw materials with aqueous hydrochloric acid at pH 4.0 and 0.8, respectively. EA-4.0 and EA-0.8 were found to scavenge the DPPH radical in a concentration-dependent manner at 17–133 μg/mL, whereas commercial apple pectin scavenged at 0.5–2 mg/mL. The antioxidant activity of EA-4.0 was the highest and exceeded the activity of EA-0.8 and a commercial apple pectin by 2 and 39 times (IC₅₀—0.050, 0.109 and 1.961 mg/mL), respectively. Pectins EA-4.0 and EA-0.8 were found to possess superoxide radical scavenging activity, with IC₅₀s equal to 0.27 and 0.97 mg/mL, respectively. Correlation analysis of the composition and activity of 32 polysaccharide fractions obtained by enzyme hydrolysis and anionic exchange chromatography revealed that the antioxidant capacity of fireweed pectins is mainly due to phenolics and is partially associated with xylogalacturonan chains. The data obtained demonstrate that pectic polysaccharides appeared to be bioactive components of fireweed leaves with high antioxidant activity, which depend on pH at their extraction.

Advanced approaches for improving bioavailability and controlled release of anthocyanins

Anthocyanins are a group of phytochemicals responsible for the purple or red color of plants. Additionally, they are recognized to have health promoting functions including anti-cardiovascular, anti-thrombotic, anti-diabetic, antimicrobial, neuroprotective, and visual protective effect as well as anti-cancer activities. Thus, consumption of anthocyanin supplement or anthocyanin-rich foods has been recommended to prevent the risk of development of chronic diseases. However, the low stability and bioavailability of anthocyanins limit the efficacy and distribution of anthocyanins in human body. Thus, strategies to achieve target site-local delivery with good bioavailability and controlled release rate are necessary. This review introduced and discussed the latest advanced techniques of designing lipid-based, polysaccharide-based and protein-based complexes, nano-encapsulation and exosome to overcome the limitation of anthocyanins. The improved bioavailability and controlled release of anthocyanins have great significance for gastrointestinal tract absorption, transepithelial transportation and cellular uptake. The techniques of applying different biocompatible materials and modifying the solubility of anthocyanins complex could achieve target site-local delivery with negligible degradation and good bioavailability in human body.

Recent advances in utilization of pectins in biomedical applications: a review focusing on molecular structure-directing health-promoting properties

The numerous health benefits of pectins justify their inclusion in human diets and biomedical products. This review provides an overview of pectin extraction and modification methods, their physico-chemical characteristics, health-promoting properties, and pharmaceutical/biomedical applications. Pectins, as readily available and versatile biomolecules, can be tailored to possess specific functionalities for food, pharmaceutical and biomedical applications, through judicious selection of appropriate extraction and modification technologies/processes based on green chemistry principles. Pectin's structural and physicochemical characteristics dictate their effects on digestion and bioavailability of nutrients, as well as health-promoting properties including anticancer, immunomodulatory, anti-inflammatory, intestinal microflora-regulating, immune barrier-strengthening, hypercholesterolemia-/arteriosclerosis-preventing, anti-diabetic, anti-obesity, antitussive, analgesic, anticoagulant, and wound healing effects. HG, RG-I, RG-II, molecular weight, side chain pattern, and degrees of methylation, acetylation, amidation and branching are critical structural elements responsible for optimizing these health benefits. The physicochemical characteristics, health functionalities, biocompatibility and biodegradability of pectins enable the construction of pectin-based composites with distinct properties for targeted applications in bioactive/drug delivery, edible films/coatings, nano-/micro-encapsulation, wound dressings and biological tissue engineering. Achieving beneficial synergies among the green extraction and modification processes during pectin production, and between pectin and other composite components in biomedical products, should be key foci for future research.

The Dietary Fiber Pectin: Health Benefits and Potential for the Treatment of Allergies by Modulation of Gut Microbiota

Purpose of Review

The incidence of allergies is increasing and has been associated with several environmental factors including westernized diets. Changes in environment and nutrition can result in dysbiosis of the skin, gut, and lung microbiota altering the production of microbial metabolites, which may in turn generate epigenetic modifications. The present review addresses studies on pectin-mediated effects on allergies, including the immune modulating mechanisms by bacterial metabolites.

Recent Findings

Recently, microbiota have gained attention as target for allergy intervention, especially with prebiotics, that are able to stimulate the growth and activity of certain microorganisms. Dietary fibers, which cannot be digested in the gastrointestinal tract, can alter the gut microbiota and lead to increased local and systemic concentrations of gut microbiota-derived short chain fatty acids (SCFAs). These can promote the generation of peripheral regulatory T cells (T_reg) by epigenetic modulation and suppress the inflammatory function of dendritic cells (DCs) by transcriptional modulation.

The dietary fiber pectin (a plant-derived polysaccharide commonly used as gelling agent and dietary supplement) can alter the ratio of Firmicutes to Bacteroidetes in gut and lung microbiota, increasing the concentrations of SCFAs in feces and sera, and reducing the development of airway inflammation by suppressing DC function.

Summary

Pectin has shown immunomodulatory effects on allergies, although the underlying mechanisms still need to be elucidated. It has been suggested that the different types of pectin may exert direct and/or indirect immunomodulatory effects through different mechanisms. However, little is known about the relation of certain pectin structures to allergies.

Newly Obtained Apple Pectin as an Adjunct to Irinotecan Therapy of Colorectal Cancer Reducing E. coli Adherence and β-Glucuronidase Activity

Colorectal cancer (CRC) is the second cause of cancer death worldwide. The composition and enzymatic activity of colonic microbiota can significantly affect the effectiveness of CRC chemotherapy. Irinotecan is a drug widely used to treat colon cancer. However, the transformation of a drug-glucuronide (SN-38G) back to its active form (SN-38) by bacterial β-glucuronidase (GUS) constitutes the primary reason for the observed intestinal toxicity of irinotecan. It was demonstrated that novel enzymatically extracted apple pectin (PC) might be a promising candidate for an adjunct to irinotecan therapy. PC itself reduced the viability of HCT 116 and Caco-2 colorectal cancer cells, induced apoptosis, and increased intracellular reactive oxygen species production. Moreover, PC enhanced the cytotoxic and proapoptotic effect of irinotecan (at concentrations below its IC₅₀), i.e., synergistic effect was recorded. Additionally, PC exhibited potent anti-inflammatory properties and prevented adhesion of prototype adherent-invasive E. coli (AIEC) LF82 strain and laboratory K-12_C600 strain to colon cancer cells. PC was also identified to be an effective inhibitor of bacterial GUS activity. Altogether, novel apple pectin was identified as a promising candidate for a supplement to irinotecan therapy that might alleviate its side-effects via inhibition of bacterial GUS and thus increasing its therapeutic efficacy.

Delineating the inherent functional descriptors and biofunctionalities of pectic polysaccharides

Pectin is a plant-based heteropolysaccharide macromolecule predominantly found in the cell wall of plants. Pectin is commercially extracted from apple pomace, citrus peels and sugar beet pulp and is widely used in the food industry as a stabilizer, emulsifier, encapsulant, and gelling agent. This review highlights various parameters considered important for describing the inherent properties and biofunctionalities of pectins in food systems. These inherent descriptors include monosaccharide composition, galacturonic acid content, degree of esterification, molecular weight, structural morphology, functional group analysis, and functional properties, such as water and oil holding capacity, emulsification, foaming capacity, foam stability, and viscosity. In this study, we also delineate their potential as a nutraceutical, prebiotic, and carrier for bioactive compounds. The biofunctionalities of pectin as an anticancer, antioxidant, lipid-lowering, and antidiabetic agent are also conceptually elaborated in the current review. The multidimensional characteristics of pectin make it a potential candidate for use in food and biomedical science.

Structural characterization and mechanisms of macrophage immunomodulatory activity of a pectic polysaccharide from Cucurbita moschata Duch

A pectic polysaccharide (named CMDP-4b) with a molecular weight of 31.97 kDa was extracted from Cucurbita moschata Duch and purified by column chromatography. On the basis of methylation, Fourier-transform infrared, monosaccharide composition, and one- and two-dimensional nuclear magnetic resonance spectroscopy analyses, the structure of CMDP-4b was determined to be composed of an α-1,4-linked homogalacturonan backbone, which was slightly acetylated and highly methyl-esterified, and branched at the O-3 position of the →4)-α-D-GalpA-6-OMe-(1→. Immunomodulatory assays showed that CMDP-4b not only induced the secretion of nitrous oxide and cytokines (i.e. IL-1β, TNF-α, and IL-6) but also promoted pinocytic and phagocytic activities of macrophages, suggesting that CMDP-4b possessed immunomodulatory activity. Moreover, toll-like receptor 4 and complement receptor 3 may play a critical role in CMDP-4b-induced macrophage activation through the NF-κB and the MAPKs signaling pathways. Our study provides the molecular basis for the potential use of CMDP-4b as a natural immunostimulant.

Unsaturated and thiolated derivatives of polysaccharides as functional matrixes for tissue engineering and pharmacology: A review

This review examines investigations into the functionalization of polysaccharides by substituents containing multiple (CC) bonds and thiol (SH) groups that are prone to (co)polymerization in the presence of thermal, redox and photoinitiators or Michael addition reactions. A comparative analysis of the approaches to grafting the mentioned substituents onto the polysaccharide macromolecules was conducted. The use of the modified polysaccharides for the design of the 3D structures, including for the development of the pore bearing matrixes of cells or scaffolds utilized in regenerative medicine was examined. These modified polymers were also examined toward the design of excipient matrixes in pharmacological compositions, including with controllable release of active pharmaceuticals, as wel as of antibacterial and antifungal agents and others. In addition, a few examples of the use of modified derivatives in other areas are given.

Enzymatically Extracted Apple Pectin Possesses Antioxidant and Antitumor Activity

The biological activity of apple pectin extracted conventionally or enzymatically using endo-xylanase and endo-cellulase, was tested in vitro. The analyses were performerd in tetraplicates and the statistical significance of the differences were assessed using ANOVA, Tukey post hoc and LSD (the least significant difference) tests. Multivariate regression analysis was applied to determine the structural components that have a crucial importance for antioxidant and antitumor properties of pectins. The pectins extracted by enzymes contained up to four times more ferulic acid and showed twice as great ability to neutralize free radicals and Fe(III) reduction. The antiradical potential positively correlated with phenols, fucose and rhamnose content. In the assays performed on HT-29 human adenocarcinoma and B16F10 melanoma cell cultures, the “green” pectins, contrary to acid isolated ones, exhibited remarkable anti-neoplastic potential while being nontoxic to nontransformed L929 cell line. The pectins in the dose of 1 mg/mL were capable of inhibiting adhesion (max 23.1%), proliferation (max 40.4%), invasion (max 76.9%) and anchorage-independent growth (max 90%) of HT-29 cells (significance level p < 0.001). These pectin preparations were slightly less active towards B16F10 cells. The enzyme-isolated apple pectins may be useful as a functional food additive and an ingredient of the ointment formulas for post-surgical melanoma treatment.

A review on orally disintegrating films (ODFs) made from natural polymers such as pullulan, maltodextrin, starch, and others

In recent years, orally disintegrating films (ODFs) have been studied as alternative ways for drug administration. They can easily be applied into the mouth and quickly disintegrate, releasing the drug with no need of water ingestion and enabling absorption through the oral mucosa. The ODFs matrices are typically composed of hydrophilic polymers, in which the natural polymers are highlighted since they are polymers extracted from natural sources, non-toxic, biocompatible, biodegradable, and have favorable properties for this application. Besides that, natural polymers such as polysaccharides and proteins can be applied either alone or blended with other synthetic, semi-synthetic, or natural polymers to achieve better mechanical and mucoadhesive properties and fast disintegration. In this review, we analyzed ODFs developed using natural polymers or blends involving natural polymers, such as maltodextrin, pullulan, starch, gelatin, collagen, alginate, chitosan, pectin, and others, to overview the recent publications and discuss how natural polymers can influence ODFs properties.

Structure analysis of a non-esterified homogalacturonan isolated from Portulaca oleracea L. and its adjuvant effect in OVA-immunized mice

We isolated and purified a pectin from Portulaca oleracea L. (P. oleracea), and analysed its structure by high-performance size exclusion chromatography (HPSEC), high-performance liquid chromatography (HPLC), gas chromatograph-mass spectrometer (GC-MS), fourier transform infrared spectroscopy (FT-IR), and ¹H, ¹³C nuclear magnetic resonance spectroscopy (NMR). The data indicated that this pectin (designated as POPW-HG) was a linear non-esterified homogalacturonan, which is unique in plants; its molecular weight was around 41.2 kDa. Meanwhile, POPW-HG as an adjuvant was evaluated in the mice immunized with OVA subcutaneously. OVA-specific antibody titres from the sera of immunized mice were tested by ELISA. It showed that POPW-HG significantly enhanced OVA-specific antibody titres (IgG, IgG1, and IgG2b) (p < 0.05) in a dose-dependent manner in the OVA-immunized mice, preliminarily indicating POPW-HG could increase an antibody response, Th1 and Th2 immune response. In addition, the ratio of IgG1/IgG2b suggested POPW-HG induced a Th2-biased response in the OVA-immunized mice. The results demonstrated POPW-HG could be a potential adjuvant candidate in vaccines.

Pectic polysaccharides from edible halophytes: Insight on extraction processes, structural characterizations and immunomodulatory potentials

The preparation, chemical properties and bio-activities of polysaccharides derived from halophytes have gained an increasing interest in the past few years. Phytochemical and pharmacological reports have shown that carbohydrates are important biologically active compounds of halophytes with numerous biological potentials. It is believed that the mechanisms involved in these bio-activities are due to the modulation of immune system. The main objective of this summary is to appraise available literature of a comparative study on the extraction, structural characterizations and biological potentials, particularly immunomodulatory effects, of carbohydrates isolated from halophytes (10 families). This review also attempts to discuss on bioactivities of polysaccharides related with their structure-activity relationship. Data indicated that the highest polysaccharides yield of around 35% was obtained under microwave irradiation. Structurally, results revealed that the most of extracted carbohydrates are pectic polysaccharides which mainly composed of arabinose (from 0.9 to 72%), accompanied by other monosaccharides (galactose, glucose, rhamnose, mannose and xylose), significant amounts of uronic acids (from 18.9 to 90.1%) and some proportions of fucose (from 0.2 to 8.3%). The molecular mass of these pectic polysaccharides was varied from 10 to 2650 kDa. Hence, the evaluation of these polysaccharides offers a great opportunity to discover novel therapeutic agents that presented especially beneficial immunomodulatory properties. Moreover, reports indicated that uronic acids, molecular weights, as well as the presence of sulfate and unmethylated acidic groups may play a significant role in biological activities of carbohydrates from halophyte species.

Alginate-based hydrogels for cancer therapy and research

Cancer is a major health issue concerning to all of us. Current treatment options are still limited due to not-selective action. Encapsulation is contemplated as an innovative approach to address systemic toxicity and tumor resistance caused by traditional therapies, while increasing encapsulated compounds bioavailability. The coating material of capsules strongly determines the success of the system. Since alginate has been proved non-toxic, biocompatible and biodegradable, it is considered a potential vehicle for therapeutic factors encapsulation. Besides, it has the particular ability to form hydrogels, which hold a high-water content and greatly resemble to natural soft tissues. The present review exposes the state-of-the-art and the most sophisticated alginate-based systems for cancer therapy and research. It begins with an overview of alginate hydrogels and the qualities that make them especially suitable for biomedical applications. In the following section, the application of alginate hydrogels as pioneering strategies for cancer treatment is described. Several examples of alginate-based delivery systems of therapeutic drugs, proteins and nucleic acids are provided. Significant emphasis is placed in both oral delivery systems and colorectal cancer therapy. Moreover, the role of alginate 3-D scaffolds for both cell culture and delivery is explained. Lastly, other applications of alginate-based hydrogels such as tumor biomarkers immunosensing and fluorescent surgical marker are included.

Characterization, biological evaluation and molecular docking of mulberry fruit pectin

Contemplating the exemplary benefits of pectin on human health, we precisely characterized and evaluated the antibacterial and anticancer activities from purified Mulberry Fruit Pectins (MFP). Here, we tested BR-2 and S-13 varieties of mulberry fruit pectins against six bacterial strains and two human cancer cell lines (HT-29 and Hep G-2), using MIC and an in vitro cell-based assay respectively. The BR-2 mulberry fruit pectin performs superior to S-13 by inhibiting strong bacterial growth (MIC = 500–1000 μg/mL) against tested bacterial strains and cytotoxic activities at the lowest concentration (10 µg/ml) against the Hep G-2 cell line. However, both tested drugs failed to exhibit cytotoxicity on the human colon cancer cell line (HT-29). Based on molecular interaction through docking, pectin binds effectively with the receptors (1e3g, 3t0c, 5czz, 6j7l, 6v40, 5ibs, 5zsy, and 6ggb) and proven to be a promising antimicrobial and anti-cancer agents. The pursuit of unexploited drugs from mulberry fruit pectin will potentially combat against bacterial and cancer diseases. Finally, future perspectives of MFP for the treatment of many chronic diseases will help immensely due to their therapeutic properties.