New findings on green sweet pepper (Capsicum annum) pectins: Rhamnogalacturonan and type I and II arabinogalactans

Insoluble dietary fibers from Hancornia speciosa alleviates chronic constipation on experimental loperamide-induced model

Constipation is one of the most prevalent intestinal disorders and is characterized by the presence of hard and dry stools, excessive effort, infrequent bowel movements, abdominal distension and pain, and others. Low fiber consumption may be one of the nutritional factors that greatly influence the development of constipation. Previous studies have observed the laxative effect of Hancornia speciosa fruit pulp. So, this study aims to extract and characterize the dietary fibers from H. speciosa fruit pulp and evaluate the laxative effect of both soluble (SDF) and insoluble (IDF) fractions on an experimental model of loperamide-induced chronic constipation. Monosaccharide and NMR analyses showed that SDF and IDF fractions were mainly composed of arabinose, indicating the presence of pectic arabinans. No changes on food and water intake and weight gain were observed. IDF fraction induced a threefold increase in number, weight and water content of fecal pellets and doubled small intestine transit rate. Similar results were obtained for SDF in a smaller intensity. Both fractions decreased the number of leukocytes in small and large intestines, suggesting a potential anti-inflammatory effect. Thus, the dietary fiber fractions from H. speciosa were effective in improving fecal parameters and alleviating constipation symptoms in the evaluated model.

Structural insights and therapeutic potential of plant-based pectin as novel therapeutic for type 2 diabetes mellitus: A review

Type 2 diabetes mellitus (T2DM) is a global health challenge with limited efficacy of current treatments, necessitating alternative therapies. Plant-derived pectin, composed of galacturonic acid and structural domains such as homogalacturonan, has shown promise as an anti-diabetic agent. Pectin exerts its therapeutic effects through multiple mechanisms, including enhancing β-cell function, regulating glucose metabolism, improving insulin sensitivity, inhibiting digestive enzymes, and restoring gut microbiota balance. Its bioactivity is influenced by physicochemical properties like molecular weight, degree of methylation, and structural complexity. This review explores the anti-diabetic potential of pectin, its structure-activity relationships, and mechanisms of action, providing insights for its development as a novel therapeutic agent in T2DM management.

Bioaccessibility of bioactive compounds and associated compounds to the indigestible fraction after in vitro digestion of three dry Capsicum annuum varieties

Mexico has a wide variety of dry chilies used in Mexican food preparation because they are spicy, a property related to the bioactive compound named capsaicin. Apart from capsaicin, dry chilies have compounds such as phenolic compounds and tocopherols. Except for phenolic compounds, capsaicin and tocopherol have not been totally assessed to measure their release from the food matrix (bioaccessibility) after in vitro digestion. Therefore, this study is aimed at analyzing the bioaccessibility of phenolic compounds, tocopherols and capsaicinoids after in vitro digestion process of three dry chilies, namely, chiltepin, Colorado, and de Arbol, as well as the bioactive compounds associated with the indigestible fraction (IF). Results indicated that the bioaccessibility values of capsaicinoids were above 80% for all the three chili varieties without showing significant differences. Although these chilies showed high capsaicinoid bioaccessibility values, there were still compounds associated with the IF that could reach the colon and exhibit bioactivity. Regarding phenolic compounds, no differences in the bioaccessibility values were observed; however, there was a major concentration of flavonoids in the IF of the Colorado and de Arbol chilies, which could have a regulatory effect on the colonic microbiome. Regarding the bioaccessibility of α-tocopherol, there was a significant difference between de Arbol and the other two varieties (above 60%). The IF of Colorado chili was a source of α-tocopherol in the colon because it had the lowest bioaccessibility percentage. The overall results demonstrate that dry chilies are a source of bioactive compounds with bioaccessibility values favorable to human health.

Water-soluble polysaccharides from Torreya grandis nuts: Structural characterization and anti-inflammatory activity

Torreya grandis (T. grandis) nuts are widely consumed as a functional food in China. In this study, we investigated the structural characteristics of T. grandis nuts polysaccharides and evaluated their potential biological functions with anti-inflammatory activities. Polysaccharides (TGP) were extracted from T. grandis nuts using water extraction and alcohol precipitation methods. Through a series of purification steps, three heteropolysaccharides (TGP-0a, TGP-2a, and TGP-3a) with distinct molecular weights, monosaccharide compositions, and surface morphologies were isolated. Their anti-inflammatory activities were screened, and TGP-0a was shown to be the most effective component. By combining NMR and methylation studies, TGP-0a was predominantly composed of linear α-1,4-glucan region and linear β-1,4-(gluco)mannan region. In cellular anti-inflammatory assays, TGP-0a significantly diminished the release of pro-inflammatory cytokines. Furthermore, by lowering the levels of iNOS and COX-2, TGP-0a decreased the release of inflammatory mediators (NO and ROS), thereby reducing oxidative stress and inflammatory response. In conclusion, T. grandis nut polysaccharides, particularly TGP-0a, show strong potential as natural anti-inflammatory agents for functional foods and pharmaceutical applications.

Associating structural characteristics to immunomodulating properties of carrot rhamnogalacturonan-I fractions

Carrot rhamnogalacturonan-I (cRG-I) is a polydisperse polysaccharide with molecular weights of 7-250 kDa. Using size exclusion chromatography cRG-I was fractionated and pooled in fractions (PF1-6). All fractions contained the same RG-I monosaccharides and similar glycosidic linkages although in varying relative amounts. The main differences were in rhamnose substitution, arabinan- and galactan side chain length and in levels of acetylation and methyl esterification. Atomic force microscopy showed either spheric or elongated structures for cRG-I and its derived fractions. To gain insight in the structure-function relationship of cRG-I, the immunomodulatory effect of the six fractions and their saponified derivatives was assessed in vitro. All fractions, except PF2, dose-dependently stimulated TNFα, IL-6, IL-1β, IL-8 and IL-10 production in peripheral blood mononuclear cells (PBMCs) of three healthy donors. Cytokine levels were largely influenced by the Mw and degree of esterification of the individual fractions. Notably, the highest Mw fraction (100 kDa) displayed the most potent activity, which was strongly reduced after the removal of ester residues by saponification. In contrast, the 75 kDa Mw population (PF2) proved inactive while its saponified counterpart exhibited substantial immunomodulatory activity. This confirmed the role of ester residues on the immune profile of RG-I subpopulations.

Emulsifying and ethanol-induced gelling properties of capsicum pectin: The impact of capsicum variety and deproteinization using the Sevag method

This study investigated the emulsifying and ethanol-induced gelling properties of capsicum pectins from bell pepper and chili pepper, and also examined the effect of deproteinization (using the Sevag method). The research revealed that bell pepper pectin (BPP) formed smaller aggregates (337 nm at pH 2) with a higher hydrophobicity in solution due to its lower molecular weight (2.02 × 105 g/mol) and higher degree of esterification (82.15 %) compared to chili pepper pectin (CPP) (3.29 × 105 g/mol, 78.33 %). Consequently, BPP exhibited superior interfacial tension reduction ability, resulting in emulsion with smaller droplet size (483 nm at pH 2). Conversely, CPP showed superior ethanol-induced gelling property in comparison to BPP, as its lower degree of esterification and higher molecular weight facilitated hydrogen bonding interactions and crosslinking during gelation. Deproteinization with the Sevag method reduced protein content, molecular weight and esterification degree of BPP and CPP, but its impact on their emulsifying properties differed significantly. Interestingly, deproteinization notably improved the ethanol-induced gelling property of both pectins, since the increased carboxyl groups in the deproteinized products promoted hydrogen bonding during gelation. This study could facilitate the comprehensive utilization of capsicum and also advance our understanding of the impact of the Sevag method.

Structural characterization of an arabinogalactan rich fraction from Bauhinia forficata Link leaves and evaluation of its effect on THP-1 macrophages

Bauhinia forficata is a medicinal plant known as cow's paw, used for many purposes. Although there are studies that aimed to elucidate compounds from the plant leaves, there is no information about its polysaccharides. This study intended to obtain a polysaccharide rich fraction from its leaves, structurally characterize the water-soluble polysaccharides, as well as evaluate their effect on THP-1 cells. From the aqueous extract, followed by purification processes, a polysaccharide fraction (TCA-S) was obtained, constituted mainly of arabinose and galactose. Bidimensional NMR (13C/1H, HSQC) and methylation analyses identified type I and type II arabinogalactans, arabinan and starch as the major polysaccharides of the fraction. TCA-S was then submitted to starch removal process and renamed as TCA-Sα. TCA-Sα (2 to 500 μg/mL) was not cytotoxic to THP-1-cells and exhibited an immunostimulatory effect by increasing the secretion of nitric oxide and both pro-inflammatory cytokine IL-1β and anti-inflammatory cytokine IL-10. Immunomodulatory effect on IL-6 secretion was observed when macrophages were treated with TCA-Sα at 500 μg/mL. Additionally, the ratio between the concentrations of pro and anti-inflammatory cytokines produced by LPS-treated cells was higher than that produced by LPS plus TCA-Sα treated ones, suggesting that the polysaccharide fraction could modulate the LPS inflammation effects.

Structural analysis and in vitro fermentation characteristics of an Avicennia marina fruit RG-I pectin as a potential prebiotic

Avicennia marina (Forssk.) Vierh. is a highly salt-tolerant mangrove, and its fruit has been traditionally used for treating constipation and dysentery. In this study, a pectin (AMFPs-0-1) was extracted and isolated from this fruit for the first time, its structure was analyzed, and the effects on the human gut microbiota were investigated. The results indicated that AMFPs-0-1 with a molecular weight of 798 kDa had a backbone consisting of alternating →2)-α-L-Rhap-(1→ and →4)-α-D-GalpA-(1→ residues and side chains composed of →3-α-L-Araf-(1→-linked arabinan with a terminal β-L-Araf, →5-α-L-Araf-(1→-linked arabinan, and →4)-β-D-Galp-(1→-linked galactan that linked to the C-4 positions of all α-L-Rhap residues in the backbone. It belongs to a type I rhamnogalacturonan (RG-I) pectin but has no arabinogalactosyl chains. AMFPs-0-1 could be consumed by human gut microbiota and increase the abundance of some beneficial bacteria, such as Bifidobacterium, Mitsuokella, and Megasphaera, which could help fight digestive disorders. These findings provide a structural basis for the potential application of A. marina fruit RG-I pectic polysaccharides in improving human intestinal health.

Heat-sealable, transparent, and degradable arabinogalactan/polyvinyl alcohol films with UV-shielding, antibacterial, and antioxidant properties

Petroleum-based packaging materials are nondegradable and unsustainable and thus are harmful to the environment. Renewable packaging films prepared from bio-based raw materials are promising alternatives to petroleum-based packaging materials. In this study, colorless and transparent bio-based films were successfully cast using a solution containing a mixture of arabinogalactan (AG) and poly (vinyl alcohol) (PVA). Vanillin was incorporated into the mixture to endow the films with UV-shielding, antioxidant, and antibacterial properties. The morphological, physical, antioxidant, and antibacterial properties of the blend films were then characterized. At an AG:PVA weight ratio of 1:3, and the vanillin content was 0.15 %, the tensile strength of the AG/PVA/Vanillin (APV) films reached ~28 MPa, while their elongation at break reached ~475 %. The addition of vanillin significantly affected the antioxidant and antibacterial properties of the blend films, which exhibited superb UV barrier capacity. The APV films exhibited extremely low oxygen transmittance, delaying the onset of mold/rot in strawberries and reducing their weight loss. Because of the heat sealability of the blend films, they can be used for encapsulating various substances, such as concentrated laundry liquid. Moreover, the blend films were recyclable and biodegradable. Thus, these films have great potential for applications that require sustainable packaging.

Structural elucidation and immunomodulatory activities in vitro of type I and II arabinogalactans from different origins of Astragalus membranaceus

Astragalus membranaceus polysaccharide (APS) possesses excellent immunomodulatory activity. However, there are several studies on the structural characterization of APS. Here, we aimed to elucidate the repeating units of polysaccharides (APS1, 106.5 kDa; APS2, 114.5 kDa) obtained from different Astragalus membranaceus origins and further investigated their immunomodulatory activities. Based on structural analysis, types of the two polysaccharides were identified as arabinogalactan-I (AG-I) and arabinogalactan-II (AG-II), and co-elution of arabinogalactans (AGs) and α-glucan was observed. The backbone of AG-I was 1,4-linked β-Galp occasionally substituted by α-Araf at O-2 and/or O-3. AG-II was a highly branched polysaccharide with long branches of α-Araf, which were attached to the O-3 of 1,6-linked β-Galp of the backbone. The presence of AGs in A. membranaceus was confirmed for the first time. The two polysaccharides could promote the expression of IL-6, IL-1β and TNF-α in RAW264.7 cells via MAPKs and NF-κB signaling pathways. The constants for APS1 and APS2 binding to Toll-like receptor 4 (TLR4) were 1.83 × 10-5 and 2.08 × 10-6, respectively. Notably, APS2 showed better immunomodulatory activity than APS1, possibly because APS2 contained more AGs. Hence, the results suggested that AGs were the vital components of APS in the immunomodulatory effect.

Phyllostachys nigra (Lodd. ex Lindl.) derived polysaccharide with enhanced glycolipid metabolism regulation and mice gut microbiome

This study focuses on the characterization and regulation of glycolipid metabolism of polysaccharides derived from biomass of Phyllostachys nigra (Lodd. ex Lindl.) root (PNr). The extracts from dilute hydrochloric acid, hot water, and 2 % sodium hydroxide solution were characterized through molecular weight, gel permeation chromatography, monosaccharides, Fourier transform infrared, and nuclear magnetic resonance spectroscopy analyses. Polysaccharide from alkali extraction and molecular sieve purification (named as: PNS2A) exhibited optimal inhibitory of 3T3-L1 cellular differentiation and lowered insulin resistance. The PNS2A is made of a hemicellulose-like main chain of →4)-β-D-Xylp-(1→ that was connected by branches of 4-O-Me-α-GlcAp-(1→, T-α-D-Galp-(1→, T-α-L-Araf-(1→, →2)-α-L-Araf-(1→, as well as β-D-Glcp-(1→4-β-D-Glcp-(1→ fragments. Oral delivery of PNS2A in diabetes mice brought down blood glucose and cholesterol levels and regulated glucose and lipid metabolism. PNS2A alleviated diabetes symptoms and body weight and protected liver and kidney function in model animals by altering the gut microbiome. Polysaccharides can be a new approach to develop bamboo resources.

A neutral heteropolysaccharide from Halenia elliptica D. Don: Extraction, structural characterization, antioxidant and antiaging activities

Halenia elliptica D. Don (H. elliptica), which is also known as "heijicao" and "luanehuamao" in China, is recognised as a valuable Tibetan medicinal plant with polysaccharides as the main active ingredient. However, studies on the polysaccharides isolated from H. elliptica are few. A polysaccharide (HEPN-1) with a molecular weight of 10.80 kDa was mainly composed of Gal, Ara, Man, Glc, Rha and Fuc in a molar ratio of 25.56:24.52:4.58:3.37:2.62:1.00. Structural analysis showed that HEPN-1 had a backbone mainly consisting of 4-β-Galp, 3,6-β-Galp and 3,4,6-β-Galp and branched chains that contained two arabinan (R1 and R2) and two heteropolysaccharide (R3 and R4) side chains. The branching degree of HEPN-1 was 0.52. Within the range of doses (75-300 μg/mL), HEPN-1 increased the enzyme activity of SOD, CAT and GSH-Px and decreased the MDA level in H2O2-induced RAW 264.7 cells in a dose-dependent manner. After 6 weeks of intragastric administration, 300 mg/kg HEPN-1 considerably improved the learning and memory deficits in mice and the antioxidant enzyme system. Moreover, the MDA formation in D-gal-induced aging mice was inhibited, possibly partly via the activation of the PI3K/Akt and Nrf2/HO-1 signalling pathways. Therefore, HEPN-1 could serve as a potential natural antioxidant to prevent aging.

Polysaccharides and Phenolic Compounds Recovered from Red Bell Pepper, Tomato and Basil By-Products Using a Green Extraction by Extractor Timatic®

Fruits and vegetables processing produces significant amounts of by-products rich in valuable bioactive compounds such as polyphenols and dietary fiber. Food by-product re-use promotes the eco-sustainability of several crops. This study aimed to apply green extractions of bioactive compounds from by-products of basil, tomato, and red bell pepper production. Tests were performed by applying extraction procedures both at laboratory scale and using the Timatic® extractor. Water and ethanol 10% and 20% were used for extraction of red bell pepper and tomato, testing different temperatures (30, 50, and 90 °C; water at 90 °C and ethanol 20% were applied for basil. The obtained phenolic extracts were analyzed by HPLC-DAD-MS. Polysaccharides of tomato and red bell pepper were extracted at laboratory scale and chemically characterized using 1H-NMR to define the methylation and acylation degree, and DLS to estimate the hydrodynamic volume. Laboratory extraction tests allowed efficient scaling-up of the process on the Timatic® extractor. Phenolic content in the dried extracts (DE) ranged 8.0-11.2 mg/g for tomato and red bell pepper and reached 240 mg/g for basil extracts. Polysaccharide yields (w/w on DM) reached 6.0 and 10.4% for dried tomato and red bell pepper, respectively. Dry extracts obtained using the Timatic® extractor and water can be useful sources of bioactive phenols. The study provided new data on tomato and red bell pepper polysaccharides that may be useful for future applications.

Influence of Ultrasonic and Chemical Pretreatments on Quality Attributes of Dried Pepper (Capsicum annuum)

This study investigates the effects of ultrasound, in combination with chemical pretreatments, on the quality attributes (total phenolic and carotenoid content, antioxidant activity (2,2-Diphenyl-1-picrylhydrazyl assay (DPPH)), ferric-reducing ability (FRAP), CIE L* a* b* color, non-enzymatic browning, rehydration ratio, textural and morphological properties) of red pepper subjected to drying (hot air drying or freeze drying). The fractional factorial design was used to assess the impact of factors. The global Derringer desirability function was used to determine the optimal conditions for the best quality attributes of dried pepper. The drying method influenced total phenolic content, a* (redness), and initial rehydration ratio; pretreatment time significantly affected FRAP antiradical activity, a*, chroma and non-browning index, while pH-value had a significant effect on the texture of dried pepper. Non-enzymatic browning was reduced to 72.6%, while the DPPH antioxidant capacity of freeze-dried peppers was enhanced from 4.2% to 71.9%. Ultrasonic pretreatment led to changes in the pepper morphology, while potassium metabisulfite (KMS) was a more effective additive than citric acid.

Plant type II arabinogalactan: Structural features and modification to increase functionality

Type II arabinogalactans (AGs) are a highly diverse class of plant polysaccharides generally encountered as the carbohydrate moieties of certain extracellular proteoglycans, the so-called arabinogalactan-proteins (AGPs), which are found on plasma membranes and in cell walls. The basic structure of type II AG is a 1,3-β-D-galactan main chain with 1,6-β-D-galactan side chains. The side chains are further decorated with other sugars such as α-l-arabinose and β-d-glucuronic acid. In addition, AGs with 1,6-β-D-galactan as the main chain, which are designated as 'type II related AG' in this review, can also be found in several plants. Due to their diverse and heterogenous features, the determination of carbohydrate structures of type II and type II related AGs is not easy. On the other hand, these complex AGs are scientifically and commercially attractive materials whose structures can be modified by chemical and biochemical approaches for specific purposes. In the current review, what is known about the chemical structures of type II and type II related AGs from different plant sources is outlined. After that, structural analysis techniques are considered and compared. Finally, structural modifications that enhance or alter functionality are highlighted.

Cold shock precooling improves the firmness of chili pepper during postharvest storage and the molecular mechanisms related to pectin

This research was conducted to explore the influence of cold shock on the firmness, a quality marker in chili pepper during 0-21 d storage and determine mechanism by cold shock impacted pectin. Chili peppers were exposed to cold shock precooling (0 ± 2 °C water/ice mixture) for 0-, 30-, 90- and 150-min, respectively. Results showed that cold shock alleviated loss of firmness throughout storage. Firmness was positively associated with sodium carbonate-soluble pectin content (r = 0.44), methylation degree of CDTA-soluble pectin (r = 0.82) and water-soluble pectin (WSP, r = 0.87), but negatively associated with WSP content (r = -0.76), and the activities of β-galactosidase (r = -0.72) and pectinlyase (r = -0.74). Cold shock for 90 min was determined to be optimal. This study confirms the applicability of cold shock precooling to maintain firmness and thereby to extend the shelf life of chili pepper.

A pectic polysaccharide from fresh okra (Abelmoschus esculentus L.) beneficially ameliorates CCl4-induced acute liver injury in mice by antioxidation, inhibition of inflammation and modulation of gut microbiota

Okra [Abelmoschus esculentus (Linn.) Moench], as a well-known medicinal and food plant, has important physiological activities and health benefits, and polysaccharide is its main bioactive component. In this study, a pectic polysaccharide (OPS-50) prepared from fresh okra pods by three-phase partitioning and gradient (NH4)2SO4 precipitation at a saturation of 50% was employed in carbon tetrachloride (CCl4)-caused acute liver damage in mice to evaluate the hepatoprotective potential. Results indicated that OPS-50 was mainly composed of a limited linear homogalacturonan backbone and abundant rhamnogalacturonan-I domains as side chains. OPS-50 exerted positively protective effects on acute liver damage induced by CCl4 in mice through relieving weight reduction and organ damage, ameliorating liver function and dyslipidemia, alleviating oxidative stress, suppressing pro-inflammatory cytokines, modulating gut microbiota, and promoting short-chain fatty acid secretion. Moreover, liver histopathology demonstrated the protective benefit of OPS-50 on CCl4-caused acute liver damage in mice. Therefore, our data suggested that the pectic OPS-50, as a dietary supplement, have great potential in preventing and treating chemical liver damages.

Comparative study of water-soluble polysaccharides isolated from leaves and roots of Isatis indigotica Fort

Water-soluble polysaccharides were isolated from the leaves and roots of Isatis indigotica Fort., and their structural features were studied and compared. One neutral polysaccharide fraction (WFIP-N) and three pectin fractions (WFIP-A-A, WFIP-A-B and WFIP-A-C) were obtained from the leaves, and one neutral polysaccharide fraction (WRIP-N) and two pectin fractions (WRIP-A-A and WRIP-A-B) were obtained from the roots. WFIP-A-B (Mw = 34.6 kDa) and WRIP-A-B (Mw = 29.9 kDa) were the major pectic polysaccharides. Monosaccharide composition, FT-IR, enzymatic hydrolysis, NMR and methylation analysis indicated that both WFIP-A-B and WRIP-A-B are composed of rhamnogalacturonan I (RG-I), rhamnogalacturonan II (RG-II) and homogalacturonan (HG) domains with mass ratios of 1.5:1.0:0.4 and 0.3:1.0:1.7, respectively. WFIP-A-B and WRIP-A-B were found to be rich in RG-I and HG domains, respectively, and mainly contained type II arabinogalactan (AG-II) and α-L-1,5-arabinan side chains, but those in WRIP-A-B were more numerous and longer. Our results provide structural features and differences between these polysaccharides which will help to elucidate their functional differences.

Polyphenolic-protein-polysaccharide conjugates from Spica of Prunella vulgaris: Chemical profile and anti-herpes simplex virus activities

Previous studies showed that the water extract (PVW) from Spica of Prunella vulgaris Linn. (Labiatae) exerts anti-herpes simplex virus (HSV) activity. Evaluation the antiviral activity of the graded ethanol precipitations indicated that 30% ethanol precipitate (PVE30) was the active principle of water extract (PVW). Further activity-oriented separation of PVE30 through salting-out method revealed that the anti-HSV activity of P. vulgaris glycoconjugates (PVG) was more potent than PVE30 and PVW, 2-fold and 4-fold, respectively. UPLC-QTOF-MS/MS, FT-IR and NMR techniques identified PVG as a type of polyphenolic-protein-polysaccharides (PPPs) with an average molecular weight of 41.69 kDa. PVG was composed of dibenzylbutyrolactone lignan units, and rich in galacturonic acid, xylose, rhamnose, rhamnose, arabinose, glucose monosaccharide units, glutamic acid and aspartic acid. Further in vitro antiviral testing confirmed that PVG substantially and stably inhibited acyclovir (ACV) resistant HSV strains; its inhibitory action was even better than the positive control ACV. Overall, our findings support PVG as a potential drug resource for anti-HSV therapy.

Effect of hydrothermal-calcium chloride treatment on pectin characteristics and related quality in green peppers during storage

Effects of hydrothermal (HT)-calcium chloride (CaCl₂) treatment on pectin characteristics and related quality in green peppers during storage were assessed. The results showed that the changes of physicochemical quality in all green peppers were similar during storage. Weight loss percentage increased, firmness, the content of free water and bound water decreased during storage. Water-soluble pectin (WSP) notably increased, but sodium carbonate-soluble pectin (SSP) and chelate-soluble pectin (CSP) decreased. Galacturonic acid (GalUA), rhamnose (Rha), galactose (Gal), and arabinose (Ara) were the crucial compositions in the backbone and branched chains of pectin in green peppers. Rha and Gal increased, but Ara decreased in pectin after storage. The changes in the ratio of Rha/GalUA, Ara/Gal, and (Gal + Ara)/Rha represented that the backbone and branched chains of pectin in green peppers depolymerized to some extent after storage. Comparing with other green peppers, HT-CaCl₂ treated green peppers posed lower weight loss percentage and WSP content, higher firmness, the content of free water, bound water, SSP, and CSP during storage. Otherwise, most pectin compositions in HT-CaCl₂ treated green peppers showed high molar ratio after storage. Hence, HT-CaCl₂ treatment was an effective way to retain pectin characteristics and related quality of green peppers, and further inhibited the softening of green peppers during storage.

Parkinson's disease patients' short chain fatty acids production capacity after in vitro fecal fiber fermentation

Animal models indicate that butyrate might reduce motor symptoms in Parkinson's disease. Some dietary fibers are butyrogenic, but in Parkinson's disease patients their butyrate stimulating capacity is unknown. Therefore, we investigated different fiber supplements' effects on short-chain fatty acid production, along with potential underlying mechanisms, in Parkinson's patients and age-matched healthy controls. Finally, it was investigated if this butyrate production could be confirmed by using fiber-rich vegetables. Different fibers (n = 40) were evaluated by in vitro fermentation experiments with fecal samples of Parkinson's patients (n = 24) and age-matched healthy volunteers (n = 39). Short-chain fatty acid production was analyzed by headspace solid-phase micro-extraction gas chromatography-mass spectrometry. Clostridium coccoides and C. leptum were quantified through 16S-rRNA gene-targeted group-specific qPCR. Factors influencing short-chain fatty acid production were investigated using linear mixed models. After fiber fermentation, butyrate concentration varied between 25.6 ± 16.5 µmol/g and 203.8 ± 91.9 µmol/g for Parkinson's patients and between 52.7 ± 13.0 µmol/g and 229.5 ± 42.8 µmol/g for controls. Inulin had the largest effect, while xanthan gum had the lowest production. Similar to fiber supplements, inulin-rich vegetables, but also fungal β-glucans, stimulated butyrate production most of all vegetable fibers. Parkinson's disease diagnosis limited short-chain fatty acid production and was negatively associated with butyrate producers. Butyrate kinetics during 48 h fermentation demonstrated a time lag effect in Parkinson's patients, especially in fructo-oligosaccharide fermentation. Butyrate production can be stimulated in Parkinson's patients, however, remains reduced compared to healthy controls. This is a first step in investigating dietary fiber's potential to increase short-chain fatty acids in Parkinson's disease.

Pectic polysaccharides from Radix Sophorae Tonkinensis exhibit significant antioxidant effects

Two pectic polysaccharides (WRSP-A2b and WRSP-A3a) have been obtained from Radix Sophorae Tonkinensis and comparatively investigated in terms of their physical properties and antioxidant activities. Monosaccharide composition, FT-IR, NMR and enzymatic analyses indicate that both WRSP-A2b (13.6 kDa) and WRSP-A3a (44.6 kDa) consist of homogalacturonan (HG), rhamnogalacturonan I (RG-I) and rhamnogalacturonan II (RG-II) domains, with mass ratios of 0.9:1.8:1 and 2.3:2.9:1, respectively. The RG-I domains were further purified and characterized. Results show that WRSP-A2b contains a highly branched RG-I domain, primarily substituted with α-(1→5)-linked arabinans, whereas WRSP-A3a contains a small branched RG-I domain mainly composed of β-(1→4)-linked galactan side chains. WRSP-A3a exhibits stronger antioxidant activity in scavenging different radicals than WRSP-A2b, a finding that may be due to its higher content of GalA residues and HG domains. Our results provide useful information for screening natural polysaccharide-based antioxidants from Radix Sophorae Tonkinensis.

Isolation, purification and structural characterization of two pectin-type polysaccharides from Coreopsis tinctoria Nutt. and their proliferation activities on RAW264.7 cells

Coreopsis tinctoria Nutt. (C.tinctoria) is an annual herb of the Compositae family with many health benefits, such as clearing heat, antioxidant and anticancer activity. In this paper, two polysaccharides were isolated from C.tinctoria, named CTAP-1 and CTAP-2, respectively. Structure of CTAP-1and CTAP-2 were elucidated by high-performance gel permeation chromatography, chemical derivative analyses, GC-MS and NMR techniques. Results reveal that they both CTAP-1 and CTAP-2 consisted of predominant amounts of galacturonic acid residues along with small amounts of arabinose, rhamnose and galactose.Both them contain homogalacturonan and rhammnogalcturan I regions in different ratio, suggesting their pectin-type features. The proliferation activities of CTAP-1 and CTAP-2 on RAW264.7 cells in vitro were detected. Results show both them have the significant proliferation effect on RAW264.7 cells when the concentration from 40 to 200 µg/mL. Given their structural characteristics and proliferation activities, the pectins are expected to be potential natural immune modulators, which need further study.

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.

Polysaccharide fractions from Handroanthus heptaphyllus and Handroanthus albus barks: Structural characterization and cytotoxic activity

Barks of trees of the genus Handroanthus are known for their antitumor activity, which is attributed to naphthoquinones. Another class of molecules that has shown antitumor activity are the polysaccharides, however those from Handroanthus barks have never been studied. Accordingly, the aim of this study was to extract polysaccharides from H. heptaphyllus and H. albus barks, to characterize them structurally and to evaluate their cytotoxic effects on the human colon and human breast cancer cell lines, Caco-2 and MCF-7, respectively. The polysaccharides were extracted with boiling water and fractionated by freeze-thawing process. The soluble polysaccharide fractions HHBSF and HABSF were characterized by monosaccharide composition, methylation and NMR analyses, and their effects on proliferation of Caco-2 and MCF-7 cells were evaluated using MTT cell viability assay. HHBSF and HABSF were mainly constituted of galactoglucomannan, type II arabinogalactan (AGII) and type I rhamnogalacturonan (RGI), however, only HABSF significantly inhibited the growth of MCF-7 (CC50 = 327 μg/mL) and Caco-2 (CC50 = 2258 μg/mL) cells. Differences in the fine structure and proportion of their polysaccharides, and maybe in the composition of associated phenolic compounds could explain the different effects of HHBSF and HABSF.

Chamomile tea: Source of a glucuronoxylan with antinociceptive, sedative and anxiolytic-like effects

Chamomile is one of the most ancient medicinal herbs known to mankind and among its traditional uses are the calming effects. However, few studies explored its effects on the central nervous system (CNS). In this study we further proceed with structural elucidation of polysaccharides from chamomile tea. A highly substituted 4-O-methyl-glucuronoxylan (fraction SN-50R) was purified and chemically characterized, presenting Xyl:GlcA ratio of 1.7:1, M_w of 500 kDa and total sugar content of 98%. Its bioactivity on pain and on CNS was explored. Animals treated with SN-50R presented antinociceptive effect and a dose-dependent decrease in the number of crossings in the activity chamber and in the open field test, as well as a significant reduction in the number of marbles buried when compared to control. These results suggest that SN-50R presented sedative and anxiolytic-like effects and may be contributing for the calming effects obtained by chamomile tea ingestion.

Isolation, purification, and structural characterization of polysaccharides from Atractylodis Macrocephalae Rhizoma and their immunostimulatory activity in RAW264.7 cells

Three water-soluble polysaccharides (AMAP-1, AMAP-2 and AMAP-3) were isolated and purified from Atractylodis Macrocephalae Rhizoma by using the combination of ion-exchange chromatography and gel permeation chromatography. The structures of the polysaccharides were characterized by chemical derivatization, HPGC, GC-MS, FT-IR, and NMR techniques. Structural analyses show that the three polysaccharides are pectin-type macromolecules consisting of homogalacturonan (HG) and rhamnogalacturonan type I (RG-I) regions in different ratios. Immunostimulatory assay highlighted that the RG-I-rich AMAP-1 and AMAP-2 with high molecular weights can stimulate RAW264.7 macrophages to release nitric oxide, but HG-rich AMAP-3 with a low molecular weight cannot. This finding suggests that the immune activity may be related to the side chains of the RG-I region, which provides a certain theoretical guidance for further exploring the structure-activity relationship. Meanwhile, AMAP-1 and AMAP-2, especially AMAP-2, from Atractylodis Macrocephalae Rhizoma show potential as immune adjuvants.

Polysaccharides from green sweet pepper increase the antineoplastic effect of methotrexate on mammary tumor cells

This study investigated the antineoplastic effects and toxicity of long-term treatment with polysaccharides from sweet green pepper (Capsicum annuum [CAP]), and concomitant treatment with CAP + methotrexate (MTX) on mammary tumor cells in vivo and in vitro. Ehrlich tumor cells were subcutaneously inoculated in female Swiss mice. The long-term treatment (31 days) with CAP (100 mg kg-1, p.o.) reduced the tumor growth and did not induce toxicity. The combined treatment protocol of 100 mg kg-1 CAP (p.o.) + 1 mg kg-1 MTX (i.p.) for 21 days inhibited the tumor growth in 95%, higher than the inhibition induced by MTX alone (1.0 or 2.5 mg kg-1, i.p.). In tumors, both CAP and CAP + MTX decreased the gene expression of Vegf, vessel area, and IL-4 and IL-10 levels, and increased IL-6 levels and the degree of necrosis. Treatment with CAP + MTX also increased TNF-α levels in tumors. Additionally, CAP + MTX treatment reduced the viability of human MDA-MB-231 and MDA-MB-436 mammary tumor cells in culture. In fact, CAP exerted antineoplastic effects in vivo and in vitro against mammary tumor cells, possibly by modulating inflammation and angiogenesis. CAP may be a promising adjunct chemotherapy with lower toxicity.

Dietary fibres from guavira pomace, a co-product from fruit pulp industry: Characterization and cellular antioxidant activity

Exotic fruits and their co-products may be valuable sources of antioxidant dietary fibres (DF) which are useful for food industry and human health. In this study, we aimed to characterize DF obtained from guavira fruit pomace and investigate its antioxidant potential employing TEAC assay as well as a cell model. The DF were chemically characterized as containing arabinan, highly-methoxylated homogalacturonan and arabinogalactan. The DF-containing fraction (CPW) presented ABTS free radical scavenger activity. MTT and DCFH-DA assay were performed to assess, respectively, changes in cell viability and the potential intracellular antioxidant activity against H₂O₂-induced oxidative stress in murine NIH 3T3 fibroblast. CPW exhibited no effects on cell viability, moreover, when administered 48 h prior the induction of H₂O₂ toxic effects, it protected the cells, significantly increasing the cell viability compared to control. This protection may be related to the observed reduction of reactive oxygen species levels. Thus, the pre-treatment of cells with guavira DF for 48 h remarkably induced a cytoprotection against pro-oxidant conditions, and may be a valuable functional compound recovered from an unexploited agroindutrial waste.

Cytotoxic effect of crude and purified pectins from Campomanesia xanthocarpa Berg on human glioblastoma cells

A new source of pectin with a cytotoxic effect on glioblastoma cells is presented. A homogeneous GWP-FP-S fraction (M_w of 29,170 g mol^-1) was obtained by fractionating the crude pectin extract (GW) from Campomanesia xanthocarpa pulp. According to the monosaccharide composition, the GWP-FP-S was composed of galacturonic acid (58.8%), arabinose (28.5%), galactose (11.3%) and rhamnose (1.1%), comprising 57.7% of homogalacturonans (HG) and 42.0% of type I rhamnogalacturonans (RG-I). These structures were characterized by chromatographic and spectroscopic methods; GW and GWP-FP-S fractions were evaluated by MTT and crystal violet assays for their cytotoxic effects. Both fractions induced cytotoxicity (15.55-37.65%) with concomitant increase in the cellular ROS levels in human glioblastoma cells at 25-400 μg mL^-1, after 48 h of treatment, whereas no cytotoxicity was observed for normal NIH 3T3 cells. This is the first report of in vitro bioactivity and the first investigation of the antitumor potential of gabiroba pectins.

Utilization of Complex Pectic Polysaccharides from New Zealand Plants (Tetragonia tetragonioides and Corynocarpus laevigatus) by Gut Bacteroides Species

Pectic polysaccharides from New Zealand (NZ) spinach (Tetragonia tetragonioides) and karaka berries (Corynocarpus laevigatus) were extracted and analyzed. NZ spinach polysaccharides comprised mostly homogalacturonan (64.4%) and rhamnogalacturonan I (5.8%), with side chains of arabinan (8.1%), galactan (2.2%), and type II arabinogalactan (7.1%); karaka berry polysaccharides comprised homogalacturonan (21.8%) and rhamnogalacturonan I (10.0%), with greater proportions of side chains (arabinan, 15.6%; galactan, 23.8%; and type II arabinogalactan, 19.3%). Screening of gut commensal Bacteroides showed that six were able to grow on the NZ spinach extract, while five were able to grow on the karaka berry extract. Analysis of the polysaccharides remaining after fermentation, by size-exclusion chromatography and constituent sugar analysis, showed that the Bacteroides species that grew on these two substrates showed preferences for the different pectic polysaccharide types. Our data suggest that, to completely degrade and utilize the complex pectin structures found in plants, members of Bacteroides and other bowel bacteria work as metabolic consortia.

Antineoplastic effect of pectic polysaccharides from green sweet pepper (Capsicum annuum) on mammary tumor cells in vivo and in vitro

The present study investigated the antineoplastic effects of pectic polysaccharides that were extracted from green sweet pepper (Capsicum annuum [CAP]) in the Ehrlich carcinoma in mice and in human mammary tumor lineages. After the subcutaneous inoculation of 2 × 10⁶ Ehrlich tumor cells, Female Swiss mice received 50, 100, or 150 mg/kg CAP or vehicle orally once daily or methotrexate (2.5 mg/kg, i.p., every 5 days) for 21 days. CAP dose-dependently reduced Ehrlich tumor growth. It also reduced the viability of MCF-7, MDA-MB-231, and MDA-MB-436 human mammary cell lineages. Treatment with CAP reduced the gene expression of vascular endothelial growth factor in vivo and in vitro, reduced vessel areas of the tumors, and induced necrosis in Ehrlich solid tumors. CAP treatment significantly increased Interleukin-6 in tumors. The antineoplastic effect of CAP appears to depend on the regulation of inflammation and angiogenesis. Further studies are encouraged to better understand the CAP potential for the treatment of breast tumors.

Structural and rheological properties of pectic polysaccharide extracted from Ulmus davidiana esterified by succinic acid

The present study was carried out to investigate the physicochemical and structural properties of pectic polysaccharide extracted from Ulmus davidiana (UDP) and to determine the physicochemical, structural, and rheological properties of esterified UDP with succinic acid (ES-UDP). The results indicated that UDP had high amounts of galacturonic acids and various neutral sugars, such as galactose, rhamnose, and glucose. UDP was identified as a low methoxyl pectin, consisting of 1,4-linked α-d-GalpA (the main backbone chain), supported by the results of Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction, and 1D Nuclear magnetic resonance (NMR) spectroscopy. In the FT-IR and XRD, no difference was detected between UPD and ES-UDPs. However, ¹H and ¹³C NMR spectra revealed that the new ester bonds were formed between a hydroxyl group of UDP and a carboxyl group of succinic acid during esterification. In the steady shear rheological analysis, the consistency index (K) of ES-UDP was significantly higher than that of UDP and increased significantly with increasing concentration of succinic acid. In the dynamic rheological analysis, the tan δ values of all ES-UDP solutions were significantly lower than those of the UDP solution.

Structural characterization of alkali-soluble polysaccharides from Panax ginseng C. A. Meyer

Panax ginseng C. A. Meyer (ginseng) has been widely used as a herb and functional food in the world. Polysaccharides are the main active components of ginseng. In this paper, the polysaccharides were sequentially extracted by 50 mM Na₂CO₃, 1 M KOH and 4 M KOH from ginseng roots treated sequentially with hot water, α-amylase and ethylenediaminetetraacetic acid extraction. Na₂CO₃-soluble ginseng polysaccharide (NGP) was fractionated into one neutral and three acidic fractions by anion exchange and gel permeation chromatography. Fourier transform infrared, NMR and methylation analysis indicated acidic fractions in NGP were highly branched rhamnogalacturonan-I domains, with  → 4)-α-GalpA-(1 → 2)-α-Rhap-(1 → disaccharide repeating units as backbone and β-1,4-galactan, α-1,5/1,3,5-arabinan and type II arabinogalactan as side chains. 1-KGP (1 M KOH-soluble ginseng polysaccharide) and 4-KGP (4 M KOH-soluble ginseng polysaccharide) were mainly composed of hemicellulose besides starch-like polysaccharides and minor pectin. Antibody detection, enzymic hydrolysis, high performance anion exchange chromatography and methylation analysis demonstrated xylan was the major component in 1-KGP, while xyloglucan was predominant in 4-KGP. Comparing the polysaccharides obtained by different solvent extractions, we have a comprehensive understanding about total ginseng polysaccharides.