Extraction, purification and structural characterization of a galactoglucomannan from the gabiroba fruit (Campomanesia xanthocarpa Berg), Myrtaceae family

Impact of particle size on the functionality of corn-derived dietary fiber-phenolic acid complexes

Milling and sieving were applied to modify corn-derived cell wall dietary fiber-phenolic acid complexes (CWDFPC) to enhance their functionality and gut fermentability. The physicochemical properties of three modified CWDFPCs (CWDFPC-M1, CWDFPC-M2, and CWDFPC-M3) were characterized, showing changes in particle size (430-73.55 μm) and bulk density (0.29-0.57 g/mL). Sieving altered the composition, with CWDFPC-M1 and CWDFPC-M3 exhibiting higher bound phenolic contents than CWDFPC-M2. Increased water holding capacity indicated improved functionalities. Modified CWDFPCs exhibited a 4-fold increase in glucose adsorption capacity, higher phenolic acid release during gastrointestinal digestion in vitro, and a greater proportion of short-chain fatty acids in fecal fermentation in vitro. Hemicellulose from CWDFPC-M3 was primarily composed of →4)-β-Xylp-(1→ and →3)-β-Xylp-(1→, and →3,4)-β-Xylp-(1→, with branches possibly including →5)-α-Araf-(1→ and →3)-α-Araf-(1→ units. These modifications highlight the potential of milling and sieving to convert CWDFPCs into valuable functional food ingredients.

The amazing native Brazilian fruits

A number of native Brazilian plant species are under exploited by the scientific community, despite the country's precious biodiversity. The vast majority of native Brazilian fruits (NBF) is source of compounds that provide many health benefits and can potentially be used to prevent diseases and formulate high-added value products. This review covers the scientific research over the last decade (2012-2022) on eight NBF, and focuses on information about the production and market panorama, physical description, physicochemical characterization, nutritional composition, their functional value of bioactive compounds and health benefits, as well as the potential for utilizations for each. The studies herein compiled reveal the outstanding nutritional value of these NBF. They are sources of vitamins, fibers, minerals and bioactive compounds that exhibit antioxidant activity, and they contain phytochemicals with anti-inflammatory action, anti-obesity and other functions that bring many health benefits to consumers. NBF can be also used as raw material for multiple products such as nectars, juices, jams, frozen pulps, liquor, among others. The dissemination of knowledge about NBF has fundamental implications worldwide.

Understanding the dynamic evolution of hemicellulose during Pinus taeda L. growth

Pinus taeda L. is a fast-growing softwood with significant commercial value. Understanding structural changes in hemicellulose during growth is essential to understanding the biosynthesis processes occurring in the cell walls of this tree. In this study, alkaline extraction is applied to isolate hemicellulose from Pinus taeda L. stem segments of different ages (1, 2, 3, and 4 years old). The results show that the extracted hemicellulose is mainly comprised of O-acetylgalactoglucomannan (GGM) and 4-O-methylglucuronoarabinoxylan (GAX), with the molecular weights and ratios (i.e., GGM:GAX) of GGM and GAX increasing alongside Pinus taeda L. age. Mature Pinus taeda L. hemicellulose is mainly composed of GGM, and the ratio of (mannose:glucose) in the GGM main chain gradually increases from 2.45 to 3.60 with growth, while the galactose substitution of GGM decreases gradually from 21.36% to 14.65%. The acetylation of GGM gradually increases from 0.33 to 0.45 with the acetyl groups mainly substituting into the O-3 position in the mannan. Furthermore, the contents of arabinose and glucuronic acid in GAX gradually decrease with growth. This study can provide useful information to the research in genetic breeding and high-value utilization of Pinus taeda L.

Structural characterization and in vitro anti-colon cancer activity of a homogeneous polysaccharide from Agaricus bisporus

Colon cancer is the third most prevalent cancer and the second most deadly cancer in the world. Anti-colon cancer activity of Agaricus bisporus polysaccharides has not been studied. In this paper, Agaricus bisporus polysaccharides were sequentially extracted by room temperature water, hot water, high pressure hot water, dilute alkaline solution and concentrated alkaline solution. A homogeneous polysaccharide (WAAP-1) was obtained using DEAE Cellulose-52 column. Physicochemical properties, structural characterization and anti-colon cancer activity of WAAP-1 were investigated. The results showed that WAAP-1 was a neutral polysaccharide with molecular weight of 10.1 kDa. The monosaccharide composition was glucose, mannose and galactose with a molar ratio of 84.95:8.97:4.50. The main chain was mainly composed of (1,4)-α-D-Glcp and (1,6)-β-D-Manp. In vitro anti-colon cancer results showed that WAAP-1 could significantly inhibit proliferation of colon cancer cell HT-29. It promoted apoptosis and inhibited epithelial mesenchymal transition of HT-29 by up-regulating the expression of Caspase-3, Bax and E-cadherin proteins and down-regulating the expression of Bcl-2 and Vimentin proteins. The results provided new potential possibilities for the development of novel functional foods or antitumor drugs.

Characterization of hemicellulose in Cunninghamia lanceolata stem during xylogenesis

In this study, hemicellulose was isolated from the apical, middle and basal segments of C. lanceolata stem to investigate the dynamic change of its structure during xylogenesis. Results showed that the C. lanceolata hemicellulose is mainly consisted of O-acetylgalactoglucomannan (GGM) which backbone is alternately linked by β-d-mannopyranosyl (Manp) and β-d-glucopyranosyl (Glcp) via (1 → 4)-glycosidic bond, while the side chains are α-d-galactopyranosyl (Galp) and acetyl. In addition, 4-O-methylglucuronoarabinoxylan (GAX) is another dominant structure of C. lanceolata hemicellulose which contains a linear backbone of (1 → 4)-β-d-xylopyranosyl (Xylp) and side chains of 4-O-Me-α-d-glucuronic acid (MeGlcpA) and α-L-arabinofuranose (Araf). The thickness of the cell wall, the ratio of GGM/GAX and the molecular weight of hemicellulose were increased as the extension of growth time. The degree of glycosyl substitutions of xylan and mannan was decreased from 10.34 % (apical) to 8.38 % (basal) and from 15.63 % (apical) to 10.49 % (basal), respectively. However, the total degree of acetylation was enhanced from 0.28 (apical) to 0.37 (basal). Transcriptome analysis showed that genes (CSLA9, IRX9H1, IRX10L, IRX15L, GMGT1, TBL19, TBL25, GUX2, GUX3, GXM1, F8H1 and F8H2) related to hemicellulose biosynthesis are mainly expressed in mature part. This study is of great significance for genetic breeding and high-value utilization of C. lanceolata.

Purification, structural characterization and antioxidant activities of two neutral polysaccharides from persimmon peel

Two neutral polysaccharides (PPP1-1 and PPP1-2) were purified from persimmon peel. PPP1-1 (21.84 kDa) was mainly composed of arabinose (22.92 %), galactose (21.09 %), glucose (35.13 %), and xylose (19.09 %), while PPP1-2 (10.42 kDa) mainly contained arabinose (32.98 %), galactose (20.81 %), glucose (26.86 %), xylose (10.46 %), and mannose (7.63 %). Methylation and NMR spectra analysis demonstrated that the backbone of PPP1-1 appeared to be →6)-α-D-Glcp-(1→, →2,6)-α-D-Glcp-(1→, →5)-α-L-Araf-(1→, and →3,5)-α-L-Araf-(1 → residues with branches consisting of →3)-α-L-Araf-(1→, →4)-α-D-Glcp-(1→, →3)-β-D-Galp-(1→, →4)-β-D-Galp-(1→, →4)-β-D-Xylp-(1→, →6)-β-D-Galp-(1→, →4)-β-D-Manp-(1→, and α-L-Araf-(1 → residues. The main chain of PPP1-2 was composed of →6)-α-D-Glcp-(1→, →5)-α-L-Araf-(1→, and →3,5)-α-L-Araf-(1 → residues with branches consisting of →3)-α-L-Araf-(1→, →1,2)-α-D-Glcp-(6→, →4)-α-D-Glcp-(1→, →3)-β-D-Galp-(1→, →4)-β-D-Galp-(1→, →6)-β-D-Galp-(1→, →4)-β-D-Xylp-(1→, →4,6)-α-D-Glcp-(1→, and →4)-β-D-Manp-(1 → residues and terminal of α-L-Araf-(1 → residue. PPP1-2 exhibited stronger antioxidant activities and better thermal stability than PPP1-1. Our results provided the foundation for further investigating the structure and biological activities of persimmon peel polysaccharides and highlighted their potential to become potential antioxidants in functional food.

Effect of Loblolly Pine (Pinus taeda L.) Hemicellulose Structure on the Properties of Hemicellulose-Polyvinyl Alcohol Composite Film

Hemicellulose is the second most abundant natural polysaccharide and a promising feedstock for biomaterial synthesis. In the present study, the hemicellulose of loblolly pine was obtained by the alkali extraction-graded ethanol precipitation technique, and the hemicellulose-polyvinyl alcohol (hemicellulose-PVA) composite film was prepared by film casting from water. Results showed that hemicellulose with a low degree of substitution is prone to self-aggregation during film formation, while hemicellulose with high branching has better compatibility with PVA and is easier to form a homogeneous composite film. In addition, the higher molecular weight of hemicellulose facilitates the preparation of hemicellulose-PVA composite film with better mechanical properties. More residual lignin in hemicellulose results in the better UV shielding ability of the composite film. This study provides essential support for the efficient and rational utilization of hemicellulose.

Structural characterization and immunoregulatory activity of a neutral polysaccharide from the roots of Apocynum venetum L

The structural characteristics and immunoregulatory activities of neutral heteropolysaccharide (AVRP-N) separated from the roots of Apocynum venetum L. were extensively investigated. The results showed that the weight average molecular mass (Mw) of AVRP-N was 6.430 × 10³ Da. Moreover, the backbone is composed of natural acetylated (1 → 4)-β-D-Man and (1 → 5)-α-L-Ara domains. The mannan is composed of →4)-β-D-Manp-(1→, →4)-β-D-Glcp-(1→, and the terminal group α-D-Galp-(1→ attached to →4,6)-β-D-Manp-(1→ at O-6. Araban is composed of →5)-α-L-Araf-(1→; the terminal group α-L-Araf-(1→attached to→2,3,5)-α-L-Araf-(1→ at O-2, O-3 and →3,5)-α-L-Araf-(1→ at O-3. In addition, the senior structure shows that AVRP-N has a triple-helix conformation. Furthermore, AVRP-N exhibited immunomodulatory effects, which could significantly regulate the proliferation of mouse splenic lymphocytes by enhancing the secretion of the cytokines (IFN-γ, IL-2, IL-4, and IL-10). Our results provide new structural and immunoregulatory information for natural polysaccharides derived from Apocynum venetum L.

Isolation, NMR characterization and bioactivity of a (4-O-methyl-α-D-glucurono)-β-D-xylan from Campomanesia xanthocarpa Berg fruits

Hemicellulose-type polysaccharides were isolated from Campomanesia xanthocarpa fruits by alkaline extraction and submitted to fractionation processes giving rise to eluted (GE-300) and retained (GR-300) fractions. GE-300 presented a mixture of galactoglucomannans (GGM) and glucuronoxylans (MGX), while the GR-300 fraction is composed only of MGX. In this way, the chemical structure of MGX, investigated by 1D ¹H, ¹³C and 2D ¹H-¹³C HSQC, ¹H-¹H COSY and ¹H-¹³C HMBC NMR spectroscopy, revealed that the chemical structure of polysaccharide is a (4-O-methyl-α-D-glucurono)-D-xylan. Deep and precise NMR chemical shift determination of clean and specific ¹H NMR glycosyl units were developed by 1D TOCSY and 1D NOESY analysis. This approach demonstrated unequivocally that 4-O-methyl-α-D-glucopyranosyl uronic acid group is linked to O-2 of a (1 → 4)-β-D-xylan in the main chain. Furthermore, MGX scavenged DPPH radical (0.5 to 1.0 mg mL^-1) and was not cytotoxic to human dermal fibroblasts at concentrations up to 1.0 mg mL^-1, as demonstrated by neutral red and crystal violet assays, evidencing in vitro biocompatibility. The structure elucidation of GR-300 together with its bioactivity assessment contributed to better understand the chemical characteristics of C. xanthocarpa hemicelluloses and may provide structural basis for future structure-property studies.

Structural characterization and intestinal protection activity of polysaccharides from Sea buckthorn (Hippophae rhamnoides L.) berries

The sea buckthorn (Hippophae rhamnoides L.) berries are rich in various bioactive components and widely used as fruit and traditional medicine. In this study, a novel heteropolysaccharide fraction (SP0.1-1) was isolated from Sea buckthorn berries. SP0.1-1 is composed of mannose, glucose, galactose, and arabinose in the molar ratio of 1:2.3:1.9:11.2 with a core structure containing 1,4-linked-α-d-Glcp, 1,4,6-linked-α-d-Glcp and 1,4-linked-α-d-Manp residues as the backbone. And the side-chains comprised of 1,3,5-linked-α-l-Araf, 1,5-linked-α-l-Araf, terminal α-Araf and 1,4-linked-β-d-Galp. Furthermore, a diet supplemented with SP0.1-1 extended the mean lifespan, enhanced antioxidant enzyme (superoxide dismutase, SOD; glutathione peroxidase, GSH-Px; and catalase, CAT) activities, and decreased the malondialdehyde (MDA) level and hydrogen peroxide (H₂O₂)-induced mortality rate in fruit flies (Drosophila melanogaster). To summarize, the study's findings will provide evidence for the development of sea buckthorn polysaccharide products.

Cellulose-hemicellulose interactions - A nanoscale view

In this work, we study interactions of five different hemicellulose models, i.e. Galactoglucomannan, O-Acetyl-Galactoglucomannan, Fuco-Galacto-Xyloglucan, 4-O-Methylglucuronoxylan, and 4-O-Methylglucuronoarabinoxylan, and their respective binding strength to cellulose nanocrystals by molecular dynamics simulations. Glucuronoarabinoxylan showed the highest free energy of binding, whereas Xyloglucan had the lowest interaction energies amongst the five models. We further performed simulated shear tests and concluded that failure mostly happens at the inter-molecular interaction level within the hemicellulose fraction, rather than at the interface with cellulose. The presence of water molecules seems to have a weakening effect on the interactions of hemicellulose and cellulose, taking up the available hydroxyl groups on the surface of the cellulose for hydrogen bonding. We believe that these studies can shed light on better understanding of plant cell walls, as well as providing evidence on variability of the structures of different plant sources for extractions, purification, and operation of biorefineries.

Macromolecular and thermokinetic properties of a galactomannan from Sophora alopecuroides L. seeds: A study of molecular aggregation

The molecular aggregation of a galactomannan (NSAP-25) from Sophora alopecuroides L. seeds was investigated, where three polydisperse systems were confirmed during particle size analysis, indicating existence of different aggregates composed of random coil chains revealed by circular dichroism. Morphologically, NSAP-25 aggregate of various sizes (200-1200 nm) was possibly multi-stranded and formed by ellipsoid-like particles (20-60 nm) composed of compact coil chain, exhibiting extended amorphous structure with chain-like branches intertwined. Hence, NSAP-25 aggregation was inevitable, which exerted an unignorable effect on augmenting flexibility (β↓, γ↓, α↓ and L_p/M_L↓) and compactness (ρ↓, d_f↑ and C_∞↓) of branched random coil chain based on macromolecular analysis, especially when concentration increased. Moreover, it could be relevant to thermokinetic behavior of random nucleation and subsequent growth (A² model and negative ΔS*) as well as good thermal stability (IPDT, ITS, t_0.05, T_m and T_p), thus conferring potential applications for NSAP-25 in food and pharmaceutical industries.

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.

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.

Antibacterial and antibiofilm activity of acetone leaf extracts of nine under-investigated south African Eugenia and Syzygium (Myrtaceae) species and their selectivity indices

BACKGROUND

Antimicrobial resistance (AMR) remains an important global health issue but the gap between AMR and development of new antimicrobials is increasing. Plant extracts may have good activity per se or may be sources of effective antimicrobial compounds which can act against planktonic and/or biofilms of pathogens. We determined the antimicrobial efficacy and cytotoxicity of some under-investigated plants from the Myrtaceae family endemic to South Africa. The ability of the plant extracts to inhibit or destroy pre-formed bacterial biofilms was also determined.

METHODS

Based on previous preliminary in vitro screening and on chemotaxonomy, nine species from the Myrtaceae family were selected. The antimicrobial activity of the crude acetone leaf extracts was determined against six common nosocomial pathogens, namely: Gram-positive bacteria (Bacillus cereus, Enterococcus faecalis, Staphylococcus aureus), Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Salmonella Typhimurium) using a two-fold serial microdilution assay with p-iodonitrotetrazolium violet as growth indicator. The number of antimicrobial compounds present in extracts was determined by bioautography. Cytotoxicity of extracts was determined against Vero kidney cells using a colorimetric tetrazolium-based assay. The total antibacterial activity (TAA) in ml/g and selectivity index (LC50/MIC) of the plant extracts were calculated. A modified crystal violet assay was used to determine the antibiofilm activity of the extracts.

RESULTS

Syzygium legatii, Syzygium masukuense, and Syzygium species A had the best activities against Gram-negative and Gram-positive bacteria (MIC) values ranging from 0.04-0.08 mg/ml. Eugenia erythrophylla had the best MIC (0.02 mg/ml) against Bacillus cereus. Many extracts had relatively low cytotoxicity (LC50 > 20 μg/ml) leading to reasonable selectivity indices. Three leaf extracts (Syzygium masukuense, Syzygium species A, and Eugenia natalitia) were moderately cytotoxic (20 μg/ml < LC50 < 100 μg/ml). The plant extracts had a good capacity to reduce biofilm formation and good to poor potential to destroy pre-formed biofilms.

CONCLUSIONS

The plant species examined in this study had varying degrees of antibacterial activity against bacterial planktonic and biofilm forms with some having good activity against both forms. Several of these selected species may be potential candidates for further investigation to isolate antimicrobial compounds and to determine the mechanism of activity.

Characterization of Polysaccharides from Feijoa Fruits ( Acca sellowiana Berg.) and Their Utilization as Growth Substrates by Gut Commensal Bacteroides Species

Polysaccharides from feijoa fruit were extracted and analyzed; the composition of these polysaccharides conforms to those typically found in the primary cell walls of eudicotyledons. The two major polysaccharide extracts consisted of mainly pectic polysaccharides and hemicellulosic polysaccharides [xyloglucan (77%) and arabinoxylan (16%)]. A collection of commensal Bacteroides species was screened for growth in culture using these polysaccharide preparations and placed into five categories based on their preference for each substrate. Most of the species tested could utilize the pectic polysaccharides, but growth on the hemicellulose was more limited. Constituent sugar and glycosyl linkage analysis showed that species that grew on the hemicellulose fraction showed differences in their preference for the two polysaccharides in this preparation. Our data demonstrate that the members of the genus Bacteroides show differential hydrolysis of pectic polysaccharides, xyloglucan, and arabinoxylan, which might influence the structure and metabolic activities of the microbiota in the human gut.