Bioactive polysaccharides from the stems of the Thai medicinal plant Acanthus ebracteatus: their chemical and physical features

Evaluation of lupine seeds (Lupinus albus L.) neutral extract as a texture improver in low-fat yogurt production

Aqueous lupine seeds (Lupinus albus L.) extracts were evaluated as a natural fat substitute in low-fat yogurt production. Thus, the chemical composition, particle size, molecular weight, total phenolic (TPC), and total flavonoids (TFC) of the selected extract were estimated. Also, the antimicrobial activity and antioxidant capacity of selected extract were investigated. Yogurt with neutral lupine extract (NeLP) had the highest all sensorial attributes compared to other extracts. Also, the incorporation of NeLP during low-fat yogurt processing increased the solid content, and viscosity, as well as improved the textural profile and sensorial attributes without any negative effect on the yogurt's color. SEM micrographs of NeLP-yogurt microstructure showed a matrix characterized by large fused casein micelles clusters with comparatively lower porosity compared to control yogurt (without NeLP). The chemical composition of NeLP indicated that the major sugar constituents are glucose and galactose with different molar fractions. The molecular weight of NeLP is 460.5 kDa with a particle size of 1519.9 nm. Also, IC50 of NeLP is 0.589 mg/ml, while TPC and TFC are 7.17, and 0.0137 g/100 g sample, respectively. Hence, lupine neutral extract (0.25%) could be used as a fat replacer or texture improver ingredient in such low-fat yogurt which led to improved its characteristics without any negative defect during 7 days at 5 °C.

The cell walls of different Chara species are characterized by branched galactans rich in 3-O-methylgalactose and absence of AGPs

Streptophyte algae are the closest relatives to land plants; their latest common ancestor performed the most drastic adaptation in plant evolution around 500 million years ago: the conquest of land. Besides other adaptations, this step required changes in cell wall composition. Current knowledge on the cell walls of streptophyte algae and especially on the presence of arabinogalactan-proteins (AGPs), important signalling molecules in all land plants, is limited. To get deeper insights into the cell walls of streptophyte algae, especially in Charophyceae, we performed sequential cell wall extractions of four Chara species. The three species Chara globularis, Chara subspinosa and Chara tomentosa revealed comparable cell wall compositions, with pectins, xylans and xyloglucans, whereas Chara aspera stood out with higher amounts of uronic acids in the pectic fractions and lack of reactivity with antibodies binding to xylan- and xyloglucan epitopes. Search for AGPs in the four Chara species and in Nitellopsis obtusa revealed the presence of galactans with pyranosidic galactose in 1,3-, 1,6- and 1,3,6-linkage, which are typical galactan motifs in land plant AGPs. A unique feature of these branched galactans was high portions of 3-O-methylgalactose. Only Nitellopsis contained substantial amounts of arabinose A bioinformatic search for prolyl-4-hydroxylases, involved in the biosynthesis of AGPs, revealed one possible functional sequence in the genome of Chara braunii, but no hydroxyproline could be detected in the four Chara species or in Nitellopsis obtusa. We conclude that AGPs that is typical for land plants are absent, at least in these members of the Charophyceae.

Effects of some medicinal plant extracts on dermal papilla cells

INTRODUCTION

Miniaturization of the hair follicles is evident on the balding scalp. Approved medications, topical minoxidil, and oral finasteride for the treatment of alopecia sometimes come with undesirable adverse effects. The study was to examine the bioactivity of medicinal plants for finding the promising source of anti-hair loss application.

METHODS

Ten ethanolic extracts were prepared from Acacia concina (Willd.) DC., Acanthus ebracteatus Vahl, Bridelia ovata Decne, Cleome viscosa L., Cocos nucifera L., Hibiscus subdariffla L., Oryza sativa L., Terminalia chebula Retz., Tinospora crispa (L.) Hook. f. & Thomson and cytotoxic tested on dermal papilla cells using MTT assay. The effect of the extracts on cell cycle was also determined using flow cytometry technique. Anti-inflammatory activity was examined by determining IL-1β inhibition in RAW 257.4 cells. In vitro study of androgenic and 5α-reductase inhibitory activities were also determined using MTT assay and enzymatic reaction couple with liquid chromatography-mass spectrometry (LC-MS), respectively.

RESULTS

Our results revealed that only A. ebracteatus promoted dermal papilla cell proliferation and the S and G2/M phases in cell cycle. A. ebracteatus also showed inhibitory activity against 5α-reductase and testosterone in reducing cell viability of the dermal papilla. Moreover, A. ebracteatus extract strongly inhibited LPS-stimulating IL-1β production in RAW 264.7 cells in a dose-dependent manner.

CONCLUSION

Our finding indicated that the ethanolic extract of A. ebracteatus is a promising candidate for anti-hair loss treatment.

A review of the ethnomedicinal uses, chemistry, and pharmacological properties of the genus Acanthus (Acanthaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

The Acanthus genus belongs to the Acanthaceae family, and its species are distributed in all continents, mainly in tropical and subtropical regions. Several traditional applications are referred to, but few scientific studies validate them. Despite this, studies in animal models corroborate some of its uses in folk medicine, such as anticancer, antidiabetic, anti-inflammatory, and antinociceptive, which encourages the research on plants of this genus.

AIM OF THE REVIEW

To our knowledge, this document is the first comprehensive review study that provides information on the geographic distribution, botanical characteristics, ethnomedicinal uses, phytochemicals, and pharmacological activities of some Acanthus species to understand the correlation between traditional uses, phytochemical, and pharmacological activities, providing perspectives for future studies.

RESULTS

In traditional medicine, Acanthus species are mainly used for diseases of respiratory, nervous and reproductive system, gastrointestinal and urinary tract, and skin illness. The most used species are A. montanus, A. ilicifolius, and A. ebracteatus. Chemical compounds (125) from different chemical classes were isolated and identified in seven species, mainly from A. ilicifolius, about 80, followed by A. ebracteatus and A. montanus, appearing with a slightly lower number with fewer phytochemical profile studies. Isolated phytoconstituents have been mainly alkaloids, phenylpropanoid glycosides, and phenylethanoids. In addition, aliphatic glycosides, flavonoids, lignan glycosides, megastigmane derivatives, triterpenoids, steroids, fatty acids, alcohols, hydroxybenzoic acids, simple phenols were also cited. Scientific studies from Acanthus species extracts and their phytoconstituents support their ethnomedical uses. Antimicrobial activity that is the most studied, followed by the antioxidant, anti-inflammatory, and anticancer properties, underlie many Acanthus species activities. A. dioscoridis, A. ebracteatus, A. hirsutus, A. ilicifolius, A. mollis, A. montanus, and A. polystachyus have studies on these activities, A. ilicifolius being the one with the most publications. Most studies were essentially performed in vitro. However, the anticancer, antidiabetic, anti-inflammatory and antinociceptive properties have been studied in vivo.

CONCLUSION

Acanthus species have remarkable phytoconstituents with different biological activities, such as antioxidant, antimicrobial, anti-inflammatory, antinociceptive, hepatoprotective, and leishmanicidal, supporting traditional uses of some species. However, many others remain unexplored. Future studies should focus on these species, especially pharmacological properties, toxicity, and action mechanisms. This review provides a comprehensive report on Acanthus genus plants, evidencing their therapeutic potential and prospects for discovering new safe and effective drugs from Acanthus species.

Structural Characterization of Polysaccharides in Waste Liquor Produced by Wet Decortication of Sesame Seeds

The wet decortication of sesame seeds produces wastewater containing diverse minerals and organic pollutants that could be valuable resources for the food industry. This investigation aimed to reclaim, purify, and characterize the polysaccharides contained in the waste liquor from the sesame decortication industry. The purified polysaccharide fractions were characterized using monosaccharide analysis, GPC (high-performance gel permeation chromatography), FT-IR (Fourier-transform infrared) spectroscopy, methylation analysis, 1D and 2D Nucleai Magnetic Resonance (NMR) analysis, and thermal analysis. Four fractions were found (SSP-1,-2,-3, -4), of which SSP-2 was proportionately the largest and most interesting. The backbone of SSP-2 is mainly composed of (1→2,4)-β-_D-Xylp residues with side chains connected to the O-4 position, with many T-β-_D-Galp and (1→5)-α-_L-Araf residues, and fewer (1→4)-α-_D-Glcp, (1→2)-α-_L-Rhap, T-α-_L-Araf, and (1→2)-β-_D-GlcpA residues. An efficient method for removing the polysaccharides would simplify wastewater treatment while finding a use for them would benefit the sesame, food, and pharmaceutical industries.

Structural Characterization and Anticoagulant Activity of a 3-O-Methylated Heteroglycan From Fruiting Bodies of Pleurotus placentodes

Pleurotus placentodes, a fungus, belongs to the Pleurotaceae family. The aim of the present study was to characterize the structure of a novel polysaccharide from fruiting bodies of P. placentodes (PPp-W) and evaluate its anticoagulant activity in vitro. The high-performance liquid chromatography and GC–MS analysis indicated that PPp-W with a molecular weight of 27.4 kDa was mainly composed of mannose (17.56%), glucose (6.37%), galactose (44.89%), and fucose (1.22%) with a certain amount of 3-O-methyled galactose. SEM, XRD, and AFM combined with Congo red test revealed that PPp-W was an irregular curly sheet with triple-helix conformation. The FT-IR, methylation, and nuclear magnetic resonance analysis indicated that PPp-W contained→6)-α-D-Galp-(1→, →6)-3-O-Me-α-D-Galp-(1→and →2, 6)-α-D-Galp-(1→ as main chain, partially substituted at O-2 and O-6 by non-reducing ends of β-D-Manp-(1→ and β-L-Fucp-(1→ with a small amount of α-1,3-linked-Glcp in backbone. PPp-W could significantly prolong APTT (12.9 ± 0.42 s, p < 0.001) and thrombin time (39.9 ± 0.28 s, p < 0.01) compared with the control group (11.45 ± 0.071 s and 38.05 ± 0.21 s), which showed that PPp-W had anticoagulant activity. These studies suggested that PPp-W was a 3-O-methylated heteroglycan and might be suitable for functional foods and natural drugs as an anticoagulant ingredient, which provided a basis for the application of polysaccharides from P. placentodes.

Separation, characterization and hypoglycemic activity in vitro evaluation of a low molecular weight heteropolysaccharide from the fruiting body of Phellinus pini

Edible mushrooms have potential in anti-diabetic phytotherapy. They are rich in natural compounds such as polysaccharides, which have been known to have antihyperlipidemic effects since ancient times. A polysaccharide fraction of PP80 and a contained low molecular-weight (Mw), water-soluble polysaccharide (PPW-1, Mw: 3.2 kDa) were isolated from the fruiting body of Phellinus pini. Both PP80 and PPW-1 possess α-glucosidase inhibition and glucose consumption amelioration in an insulin-resistant HepG2 cell model. The α-glucosidase inhibitory activity of PPW-1 (IC50 = 2.2 ± 0.1 mg mL-1) is significantly (P < 0.01) higher than those of PP80 (IC50 = 13.1 ± 0.5 mg mL-1) and acarbose (IC50 = 4.3 ± 0.2 mg mL-1), behaving in a non-competitive inhibition manner. The structural characterization results indicated that PPW-1 is a homogeneous heteropolysaccharide composed of d-glucose, d-mannose, d-galactose and l-rhamnose. The major backbone of PPW-1 is primarily comprised of 1,6-linked glucopyranose, every third residue of which is branched at the O-3 position by a side chain consisting of 1,3-linked and terminal glucopyranose. In addition, small amounts of 1,2-linked-α-d-Manp, 1,6-linked-3-O-Me-α-d-Galp and rhamnose exist in PPW-1. In summary, PPW-1 is a novel heteropolysaccharide with potent in vitro hypoglycemic activity, and it may be a potential dietary component for improving glucose homeostasis.

Isolation, Identification, and Anti-Inflammatory Activity of Polysaccharides of Typha angustifolia

The present study aimed to purify, structurally characterize, and evaluate the anti-inflammatory activity of the polysaccharide extracted from Typha angustifolia. Two purified polysaccharides (PTA-1 and PTA-2) were obtained via DEAE-52 cellulose chromatography. Their structural characterizations and antioxidant activity were in vitro analyzed. To evaluate the anti-inflammatory activity of PTA-2, the levels of inflammatory cytokines, intracellular ROS production, and the inhibitory effects of the transcriptional activation of the nuclear factor kappa B (NF-κB) signaling pathway were determined. PTA-1 comprises glucose (100%) with α-(1 → 3) glycosidic bonds, and PTA-2 comprises glucose (66.7%) and rhamnose (33.3%) formed by β-(1 → 3) glycosidic bonds. PTA-1 and PTA-2 showed strong antioxidant activity in vitro. Moreover, PTA-2 intervention (50, 100, and 200 μg/mL) suppressed the production of inflammatory cytokines, the activation of NF-κB signaling, and reactive oxygen species production significantly. The results identified PTA-2 as a natural product that could be applied in anti-inflammatory drugs.

Macromolecular Model of the Pectic Polysaccharides Isolated from the Bark of Norway Spruce (Picea abies)

The bark of Norway spruce (Picea abies) contains up to 13% pectins that can be extracted by pressurized hot water, which constitute a valuable renewable resource in second-generation lignocellulosic biorefineries. This article proposes, for the first time, structural molecular models for the pectins present in spruce bark. Pectin fractions of tailored molar masses were obtained by fractionation of the pressurized hot water extract of the inner bark using preparative size-exclusion chromatography. The monosaccharide composition, average molar mass distribution, and the glycosidic linkage patterns were analyzed for each fraction. The pectin fraction with high molecular weight (M_w of 59,000 Da) contained a highly branched RG-I domain, which accounted for 80% of the fraction and was mainly substituted with arabinan and arabinogalactan (type I and II) side chains. On the other hand, the fractions with lower molar masses (M_w = 15,000 and 9000 Da) were enriched with linear homogalacturonan domains, and also branched arabinan populations. The integration of the analytical information from the macromolecular size distributions, domain composition, and branch lengths of each pectin fraction, results in a comprehensive understanding of the macromolecular architecture of the pectins extracted from the bark of Norway spruce. This paves the way for the valorization of spruce bark pectic polymers in targeted applications based on their distinct polymeric structures and properties.

Sulfated modification, characterization and bioactivities of an acidic polysaccharide fraction from an edible mushroom Pleurotus eous (Berk.) Sacc

The acidic fraction (P3a) of Pleurotus eous was successfully sulfated by sulphur trioxide-pyridine complex method. The effect of sulfate modification (SP3a) on the structure, physicochemical properties and in vitro biological activity of P3 was studied. The structural characteristics were established by UV absorption, FT-IR, HPGPC and GC-MS. Biological studies were carried out, such as in vitro antioxidant, anticoagulant, anti-tumour and antibacterial activities. The sulfation process changed its physicochemical and biological characteristics. Compared with P3a, the molecular weight of SP3a is reduced. P3a and SP3a are composed of galactose, xylose, arabinose with different molar percentages. Sulfated derivatives have strong antioxidant and anticoagulant properties. Compared with P3a, SP3a showed obvious cytotoxicity to Jurkat and HeLa cells. SP3a showed a higher inhibition zone for Gram-positive and Gram-negative bacteria. This article demonstrates that sulfation is an effective way to enhance biological activity, especially SP3a is a promising candidate for bioactive macromolecules and has great potential for industrial and biomedical applications.

The anti-inflammatory properties of Acanthus Ebracteatus, Barleria Lupulina and Clinacanthus Nutans: a systematic review

This appraisal is comprised of the inflammatory studies that have been conducted on Clinacanthus nutans, Acanthus ebracteatus, and Barleria lupulina. The review aims to provide a comprehensive evaluation of the supporting and contradictory evidence on each plants' anti-inflammatory properties, whilst addressing the gaps in the current literature. The databases used to obtain relevant studies were Google Scholar, ResearchGate, PubMed and Nusearch (University of Nottingham). A total of 13 articles were selected for this review. A. ebracteatus was found to suppress neutrophil migration and weakly inhibits chronic inflammatory cytokines. Furthermore, B. lupulina and C. nutans were shown to possess very similar anti-inflammatory properties. The studies on C. nutans indicated that its anti-inflammatory effect is strongly related to the inhibition of toll-like receptor 4 (TLR4). Moreover, several phytoconstituents isolated from B. lupulina were shown to activate the anti-inflammatory Nrf2 pathway. Overall, all the studies have provided evidence to support the use of these plants as anti-inflammatory herbal remedies. However, their exact mechanism of action and the responsible phytoconstituents are yet to be established.

Validation of a Rapid GC-MS Procedure for Quantitative Distinction between 3-O-Methyl- and 4-O-Methyl-Hexoses and Its Application to a Complex Carbohydrate Sample

Methylation of one hydroxyl group of monosaccharides occurs in some bacteria, fungi, worms, molluscs, and also in plants. Although knowledge on the exact functions of this process is missing, methylation is an option to modulate glycan structures thereby leading to new biological activities. In plants, methylated monosaccharides are often present in minor amounts and, therefore, overseen in analytical investigations. A special difficulty is the distinction between 3-O-methyl- and 4-O-methyl-hexoses, due to similar fragmentation patterns of methylated alditol acetates in gas-chromatography with mass spectrometric detection and, in the case of galactose, identical retention times due to symmetry. We, therefore, developed and validated an easy method for the quantitative distinction between 3-O-methyl- and 4-O-methyl-hexoses and showed its functionality by quantification of 3-O-methyl galactose in a high molecular weight polysaccharide mixture from the charophyte Spirogyra. A systematic search for methylated monosaccharides in different plant lineages may offer new insights in plant cell wall evolution.

Physiochemical, kinetic and thermodynamic studies on Aspergillus wewitschiae MN056175 inulinase with extraction of prebiotic and antioxidant Cynara scolymus leaves fructo-oligosaccharides

Utilization of agricultural wastes as cheap natural resources for production of bioactive products is currently attracting global attention. For this purpose, this study focused on isolation of Aspergillus wewitschiae MN056175 as promising producer of inulinase, then investigating physiochemical, kinetics and thermodynamics of the obtained inulinase, and its ability to extract bioactive fructo-oligosaccharides (FOS) from Cynara scolymus leaves (artichoke leaves, AL). A. wewitschiae MN056175 inulinase gave the maximum activity at temperature 60 °C and inulin concentration 1%. The kinetics including K_m and V_max were determined to be 105.26 mg·ml^-1 and 83.33 μmol·ml^-1·min^-1, respectively. The thermodynamics including, E_a (activation energy) and E_d (activation energy for denaturation) were determined to be 21.82 and 73.21 kJ·mol^-1, K_d, T_1/2, D-value, ΔH°, ΔG° and ΔS° at 40, 50 and 60 °C which indicated the stability of A. wewitschiae MN056175 inulinase. Moreover, this inulinase was capable of hydrolyzing Cynara scolymus leaves into reducing sugar and 15 FOS with different DP, total carbohydrate, and protein content under different conditions designed by central composite design (CCD). The 15 AL FOS showed different high antioxidant and prebiotic activities. Central FOS with probiotic bacteria exhibited significant antimicrobial activity against tested gram positive bacteria in a way higher than those recorded against gram negative bacteria.

Two Novel Polysaccharides in Psoralea corylifolia L and anti-A549 Lung Cancer Cells Activity In Vitro

Two novel water soluble heteroglycan (PCp-I and PCp-II) with anti-A549 lung cancer cells activity were isolated from Psoralea corylifolia L. Their average molecular weights were 2.721 × 104 and 2.850 × 104. PCp-I and PCp-II had the same monosaccharide composition, but their molar ratios were different. Based on methylation and NMR spectroscopy, the part structure of PCp-I was identified. The results of scanning electron microscope (SEM) showed that PCp-I had an irregular porous structure and PCp-II was flaky and irregularly curved. The results of thermogravimetry-differential scanning calorimetry (TG-DSC) showed that PCp-I and PCp-II had good thermal stability. Furthermore, PCp-I and PCp-II exhibited significant anti-A549 lung cancer cells activity (IC50 = 64.84 and 126.30 μM) in vitro.

In vitro evaluation of anti-epidermoid cancer activity of Acanthus ebracteatus protein hydrolysate and their effects on apoptosis and cellular proteins

Acanthus ebracteatus Vahl. is commonly consumed with the aim of curing cancer, inflammatory conditions and skin diseases in traditional Thai medicine. It is known to contain various phytochemicals; however, very little is known about the effects of A. ebracteatus protein hydrolysate on cancer cells, including its molecular mechanisms. The present study therefore investigated the anti-cancer activity of A. ebracteatus protein hydrolysates against epidermoid cancer of the skin cell line A431. Their effects on the apoptosis pathway and expression of proteins involved in the regulation of apoptosis, cell proliferation or cell cycle were also investigated. Crude extract of protein hydrolysate, partially purified peptides and purified peptides extracted from the aerial part of A. ebracteatus were administered to the A431 cells. The cytotoxicity effects were then determined using an MTT assay. As a result, A. ebracteatus protein hydrolysate significantly inhibited A431 cells with half inhibitory concentration equals to 425.9 ng protein/ml. By performing Annexin V assay, the partially purified peptides of A. ebracteatus were demonstrated to enhance the apoptosis pathway. Furthermore, western blot analysis revealed that the partially purified peptides of A. ebracteatus increased protein expression levels of RelA (p65) and Cyclin D1 proteins. However, A. ebracteatus did not increase the expression levels of p53-serine 15 phosphorylation (Ser15P).

Neutral Polysaccharide from the Leaves of Pseuderanthemum carruthersii: Presence of 3-O-Methyl Galactose and Anti-Inflammatory Activity in LPS-Stimulated RAW 264.7 Cells

Pseuderanthemum carruthersii (Seem.) Guillaumin is a native tree in Vietnam. The water extract of the leaves from this tree gives a highly viscous product that has been used to heal wounds and treat inflammations. Our previous studies showed that the leaves of P. carruthersii have a high content of polysaccharides. In this study, the structure and influence of the neutral polysaccharide from Pseuderanthemum carruthersii (PCA1) on lipopolysaccharide (LPS)-stimulated RAW264.7 cells were investigated. The PCA1 isolated from P. carruthersii is a galactan-type polysaccharide, containing galactose (77.0%), 3-O-methyl galactose (20.0%), and arabinose (3.0%). Linkage analysis of PCA1 showed that both the 3-O-methyl galactose and galactose were 1,4-linked. The presence of 3-O-methyl galactose units as part of the polysaccharide is important and can be used as a chemotaxonomic marker. The molecular weight of the PCA1 was 170 kDa. A PCA1 concentration of 30–40 μg/mL strongly inhibited TNFα, IL-1β, and IL-6 inflammatory cytokine production, and reactive oxygen species (ROS) release. PCA1 had inhibitory activities on pro-inflammatory cytokine and ROS release in LPS-stimulated mouse macrophages in vitro through MAPK signaling.

From waste to high-value product: Jackfruit peel derived pectin/apatite bionanocomposites for bone healing applications

Public requirements encouraged by the current asset framework drive industry to expand its general effectiveness by enhancing existing procedures or finding new uses for waste. Thus, the aim of this study was the isolation, fabrication, and characterization of pectin derived from jackfruit (Artocarpus heterophyllus) peels and the generation of hybrid of pectin (P)/apatite (HA) (P/HA) bionanocomposites. In this process, the natural pectin polymer derived from the peel of jackfruits was used in different concentrations for the fabrication of HA bionanocomposites. Characterization of the isolated pectin and bionanocomposites samples was performed with ¹H NMR and ¹³C NMR, FTIR, XRD, SEM-EDX, and HR-TEM. Cytocompatibility, ALP, fibroblast stem cells, anti-inflammatory and cell adhesion testing of the fabricated bionanocomposites was showed good biocompatibility. Our results signify that the fabricated bionanocomposites might be applicable as bone graft materials.

Southeast Asian Medicinal Plants as a Potential Source of Antituberculosis Agent

Despite all of the control strategies, tuberculosis (TB) is still a major cause of death globally and one-third of the world's population is infected with TB. The drugs used for TB treatment have drawbacks of causing adverse side effects and emergence of resistance strains. Plant-derived medicines have since been used in traditional medical system for the treatment of numerous ailments worldwide. There were nine major review publications on antimycobacteria from plants in the last 17 years. However, none is focused on Southeast Asian medicinal plants. Hence, this review is aimed at highlighting the medicinal plants of Southeast Asian origin evaluated for anti-TB. This review is based on literatures published in various electronic database. A total of 132 plants species representing 45 families and 107 genera were reviewed; 27 species representing 20.5% exhibited most significant in vitro anti-TB activity (crude extracts and/or bioactive compounds 0–<10 µg/ml). The findings may motivate various scientists to undertake the project that may result in the development of crude extract that will be consumed as complementary or alternative TB drug or as potential bioactive compounds for the development of novel anti-TB drug.

Sugar composition of the pectic polysaccharides of charophytes, the closest algal relatives of land-plants: presence of 3-O-methyl-D-galactose residues

BACKGROUND AND AIMS

During evolution, plants have acquired and/or lost diverse sugar residues as cell-wall constituents. Of particular interest are primordial cell-wall features that existed, and in some cases abruptly changed, during the momentous step whereby land-plants arose from charophytic algal ancestors.

METHODS

Polysaccharides were extracted from four charophyte orders [Chlorokybales (Chlorokybus atmophyticus), Klebsormidiales (Klebsormidium fluitans, K. subtile), Charales (Chara vulgaris, Nitella flexilis), Coleochaetales (Coleochaete scutata)] and an early-diverging land-plant (Anthoceros agrestis). 'Pectins' and 'hemicelluloses', operationally defined as extractable in oxalate (100 °C) and 6 m NaOH (37 °C), respectively, were acid- or Driselase-hydrolysed, and the monosaccharides analysed chromatographically. One unusual monosaccharide, 'U', was characterized by (1)H/(13)C-nuclear magnetic resonance spectroscopy and also enzymically.

KEY RESULTS

'U' was identified as 3-O-methyl-D-galactose (3-MeGal). All pectins, except in Klebsormidium, contained acid- and Driselase-releasable galacturonate, suggesting homogalacturonan. All pectins, without exception, released rhamnose and galactose on acid hydrolysis; however, only in 'higher' charophytes (Charales, Coleochaetales) and Anthoceros were these sugars also efficiently released by Driselase, suggesting rhamnogalacturonan-I. Pectins of 'higher' charophytes, especially Chara, contained little arabinose, instead possessing 3-MeGal. Anthoceros hemicelluloses were rich in glucose, xylose, galactose and arabinose (suggesting xyloglucan and arabinoxylan), none of which was consistently present in charophyte hemicelluloses.

CONCLUSIONS

Homogalacturonan is an ancient streptophyte feature, albeit secondarily lost in Klebsormidium. When conquering the land, the first embryophytes already possessed rhamnogalacturonan-I. In contrast, charophyte and land-plant hemicelluloses differ substantially, indicating major changes during terrestrialization. The presence of 3-MeGal in charophytes and lycophytes but not in the 'intervening' bryophytes confirms that cell-wall chemistry changed drastically between major phylogenetic grades.

Purification and Structural Identification of Polysaccharides from Bamboo Shoots (Dendrocalamus latiflorus)

Three kinds of polysaccharides, namely, BSP1A, BSP2A, and BSP3B, were isolated from raw bamboo shoot (Dendrocalamus latiflorus) after purification and classification by DEAE cellulose-52 (ion-exchange chromatography) and Sephadex G-50. The molecular weights of BSP1A, BSP2A, and BSP3B were 10.2, 17.0 and 20.0 kDa, respectively, which were measured through GPC (gel performance chromatography) methods. BSP1A contained arabinose, glucose, and galactose in a molar ratio of 1.0:40.6:8.7. BSP2A and BSP3B contained arabinose, xylose, glucose, and galactose in molar ratios of 6.6:1.0:5.2:10.4 and 8.5:1.0:5.1:11.1, respectively. The existence of the O-glycopeptide bond in BSP1A, BSP2A, and BSP3B was demonstrated by β-elimination reaction. FTIR spectra of the three polysaccharides showed that both BSP2A and BSP3B contained β-D-pyranose sugar rings. However, BSP1A exhibited both β-D-pyranose and α-D-pyranose sugar rings. Congo red test indicated that BSP1A and BSP2A displayed triple helix structures, but BSP3B did not. NMR spectroscopy revealed that BSP1A may exhibit a β-1,6-Glucan pyran type as the main link, and few 1,6-glycosidic galactose pyranose and arabinose bonds were connected; BSP2A mainly demonstrated → 5)β-Ara(1 → and → 3)β-Gal(1 → connection. Furthermore, BSP3B mainly presented → 3)β-Glu(1 → and → 3)β-Gal(1 → connection and may also contain few other glycosidic bonds.

Novel banana peel pectin mediated green route for the synthesis of hydroxyapatite nanoparticles and their spectral characterization

Hydroxyapatite [HAP, Ca10(PO4)6(OH)2] is the main inorganic component of natural bone and is widely used in various biomedical applications. In this paper, we have reported the synthesis of HAP nanoparticles by banana peel pectin mediated green template method. The pectin extracted from the peels of banana and its various concentrations were exploited in our study to achieve a controlled crystallinity, particle size as well as uniform morphology of HAP. The extracted pectin was characterized by spectral techniques like Fourier transform infrared spectroscopy (FTIR) for the functional group analysis, proton-1 nuclear magnetic resonance spectroscopy ((1)H NMR) and carbon-13 nuclear magnetic resonance spectroscopy ((13)C NMR) for the identification of H and C atoms in the extracted pectin, respectively. The HAP nanoparticles were synthesized using different concentrations of the as-extracted pectin. The purity, crystallinity and morphology of the as-synthesized HAP nanoparticles were evaluated by FTIR, X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDAX) and transmission electron microscopy (TEM), respectively. Moreover the antibacterial activity of HAP nanoparticles was evaluated against the gram positive and negative bacteria like Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), respectively. The experimental results revealed that the HAP nanoparticles synthesized in the presence of an optimized concentration of pectin are pure, low crystalline, spherical and discrete particles with reduced size. Also, the HAP sample derived in the presence of pectin showed an enhanced antibacterial activity than that of the HAP synthesized in the absence of pectin. Hence, the HAP nanoparticles synthesized using pectin as a green template can act as a good biomaterial for biomedical applications.

Methylation--an uncommon modification of glycans

A methyl (Me) group on a sugar residue is a rarely reported event. Until now, this type of modification has been found in the animal kingdom only in worms and molluscs, whereas it is more frequently present in some species of bacteria, fungi, algae and plants, but not in mammals. The monosaccharides involved as well as the positions of the Me groups on the sugar vary with species. Methylation appears to play a role in some recognition events, but details are still unknown. This review summarises the current knowledge on methylation of sugars in all types of organism.

Acanthus ebracteatus Vahl. ethanol extract enhancement of the efficacy of the collagen scaffold in wound closure: a study in a full-thickness-wound mouse model

Acanthus ebracteatus Vahl. is a Thai herb that is effective in wound healing. We sought to quantitatively determine whether or not the combined application of Acanthus ebracteatus Vahl. and a collagen scaffold will increase wound closure and angiogenesis. Balb/c mice (body weight: 22-25 g) were anesthetized with sodium thiopental. The dorsal skin incision measuring 1.5 × 1.5 cm was made and then deepened using scissors to produce a full-thickness incision down to the level of the panniculus carnosus. The size of the wound was approximately 10% of the total body surface area. The collagen sheet was implanted onto the wound. Animals were divided into 4 major groups as follows: wound with normal saline (W-NSS), wound treated with 0.3 g/kg BW of Acanthus ebracteatus Vahl. extract (W-AE (0.3 g/kg.bw)), wound implanted with collagen scaffold (W-Coll), and wound implanted with collagen scaffold and treated with 0.3 g/kg BW of Acanthus ebracteatus Vahl. (W-Coll-AE combination). On day 14, the W-Coll-AE group showed decreased wound areas and increased capillary vascularity (CV) when compared to the other 3 groups, W-NSS, W-AE0.3, and W-Coll. In the present study, the combination of AE0.3 with collagen showed the best effect on skin angiogenesis and promoted wound closure with less neutrophil infiltration.

Effects of Acanthus ebracteatus Vahl on tumor angiogenesis and on tumor growth in nude mice implanted with cervical cancer

Purpose

The aim of this study was to examine the effects of the crude extract of Acanthus ebracteatus Vahl (AE) on tumor growth and angiogenesis by utilizing a tumor model in which nude mice were implanted with cervical cancer cells containing human papillomavirus 16 DNA (HPV-16 DNA).

Materials and methods

The growth-inhibitory effect of AE was investigated in four different cell types: CaSki (HPV-16 positive), HeLa (HPV-18 positive), hepatocellular carcinoma cells (HepG2), and human dermal fibroblast cells (HDFs). The cell viabilities and IC₅₀ values of AE were determined in cells incubated with AE for different lengths of time. To conduct studies in vivo, female BALB/c nude mice (aged 6–7 weeks, weighing 20–25 g) were used. A cervical cancer-derived cell line (CaSki) with integrated HPV-16 DNA was injected subcutaneously (1 × 10⁷ cells/200 μL) in the middle dorsum of each animal (HPV group). One week after injection, mice were fed orally with AE crude extract at either 300 or 3000 mg/kg body weight/day for 14 or 28 days (HPV-AE groups). Tumor microvasculature and capillary vascularity were determined using laser scanning confocal microscopy. Tumor tissue was collected from each mouse to evaluate tumor histology and vascular endothelial growth factor (VEGF) immunostaining.

Results

The time-response curves of AE and the dose-dependent effect of AE on growth inhibition were determined. After a 48-hour incubation period, the IC₅₀ of AE in CaSki was discovered to be significantly different from that of HDFs (P < 0.05). A microvascular network was observed around the tumor area in the HPV group on days 21 and 35. Tumor capillary vascularity in the HPV group was significantly increased compared with the control group (P < 0.001). High-dose treatment of AE extract (HPV-3000AE group) significantly attenuated the increase in VEGF expression and tumor angiogenesis in mice that received either the 14- or 28-day treatment period (P < 0.001).

Conclusion

Our novel findings demonstrated that AE crude extract could inhibit cervical cancer growth, VEGF expression, and angiogenesis in a CaSki-cell transplant model in mice.

Prebiotic activity of polysaccharides extracted from Gigantochloa levis (Buluh beting) shoots

Bamboo shoot crude polysaccharides (BSCP) extracted from the shoots of Gigantochloa levis gave about 3.27 ± 0.18% on dry basis and a very minute percentage of protein (0.02 ± 0.01%). The molecular weight of BSCP estimated by gel chromatography was found to be around 7.49 × 10³ Da, while the molecular weights of purified fractions (F1 to F5) were around 1550.96, 1471.63, 1685.78, 1691.61 and 1551.67 Da, respectively. The FTIR spectrum of BSCP revealed the possibility that the extract contains β-glucan, which can be considered a valuable compound for the medical and food industries. These relate to the resistance of BSCP towards artificial human gastric juice which is more than 99%. Prebiotic activity tested using BSCP as a carbon source showed significant increase in the growth of B. animalis ATCC 1053, B. longum BB 536 and L. acidophilus ATCC 4356 as compared to the use of FOS. Survivality of S. choleraesuis JCM 6977 was found to be slower in both BSCP and FOS. Study conducted reflects a good sign for the BSCP to be exploited as a promising prebiotic.

Natural products from semi-mangrove flora: source, chemistry and bioactivities

This review covers the source, chemistry and bioactivities of natural products from semi-mangrove species worldwide. The chemotaxonomy of semi-mangrove plants and total synthesis of heritol analogues, which are potential biocompatible pesticides, are discussed.1 Introduction, 2 Acanthaceae, 2.1 Acanthus, 2.1.1 Aliphatic glycosides, 2.1.2 Alkaloids, 2.1.3 Flavonoids, 2.1.4 Lignan glycosides, 2.1.5 Megastigmane and phenolic glycosides, 2.1.6 Phenylethanol glycosides, 2.1.7 Triterpenoids, 2.1.8 Miscellaneous, 2.1.9 Bioactivities, 3 Euphorbiaceae, 3.1 Excoecaria, 3.1.1 Diterpenoids, 3.1.2 Miscellaneous, 3.1.3 Bioactivities, 4 Lythraceae, 4.1 Pemphis acidula, 5 Sterculiaceae, 5.1 Heritiera littoralis, 5.1.1 Flavones, 5.1.2 Triterpenoids, 5.1.3 Benzene derivatives, 5.1.4 Sesquiterpenes, 5.1.5 Steroids, 6 Total syntheses of heritol and its analogues, 7 Chemotaxonomy and concluding remarks, 8 Acknowledgements 9 References.

Pectic polysaccharides from Biophytum petersianum Klotzsch, and their activation of macrophages and dendritic cells

The Malian medicinal plant Biophytum petersianum Klotzsch (Oxalidaceae) is used as a treatment against various types of illnesses related to the immune system, such as joint pains, inflammations, fever, malaria, and wounds. A pectic polysaccharide obtained from a hot water extract of the aerial parts of B. petersianum has previously been reported to consist of arabinogalactans types I and II (AG-I and AG-II), probably linked to a rhamnogalacturonan backbone. We describe here further structural characteristics of the main polysaccharide fraction (BP1002) and fractions obtained by enzymatic degradations using endo-alpha-d-(1-->4)-polygalacturonase (BP1002-I to IV). The results indicate that in addition to previously reported structures, rhamnogalacturan type II and xylogalacturonan areas appear to be present in the pectic polymer isolated from the plant. Atomic force microscopy confirmed the presence of branched structures, as well as a polydisperse nature. We further tested whether the BP1002 main fraction or the enzymatically degraded products could induce immunomodulating activity through stimulation of subsets of leukocytes. We found that macrophages and dendritic cells were activated by BP1002 fractions, while there was little response of T cells, B cells, and NK cells. The enzymatic treatment of the BP1002 main fraction gave important information on the structure-activity relations. It seems that the presence of rhamnogalacturonan type I is important for the bioactivity, as the bioactivity decreases with the decreased amounts of rhamnose, galactose, and arabinose. The demonstration of bioactivity by the plant extracts might indicate the mechanisms behind the traditional medical use of the plant.

The system of xylogalactans from the red seaweed Jania rubens (Corallinales, Rhodophyta)

The main acidic polysaccharides from the red seaweed Jania rubens share the general characteristics of corallinans (agar-like xylogalactans). After fractionation by ion-exchange chromatography, ten fractions were separated and characterized by sugar composition, other components, methylation, ethylation, desulfation-methylation, and NMR analyses. The main group of fractions carry the agaran disaccharidic repeating unit [-->3)-beta-D-Gal-(1-->4)-alpha-L-Gal-(1-->] substituted mainly on O-6 of the beta-D-Gal unit by beta-xylosyl side stubs, and less with sulfate or methoxyl groups, and also on O-2 of the alpha-l-Gal unit with methoxyl or sulfate, or less on O-3 of the same unit with methoxyl groups. These features are somehow common to the four members of the order already studied. However, a sugar uncommon to the order appears in moderate proportions for all the fractions: it is 3,6-anhydro-l-galactose (partly sulfated or methoxylated on O-2) replacing the L-Gal unit. Besides, several other structural features never found in the order (and uncommon in any polysaccharide) appear in some minor fractions: the presence of side stubs of 2,3-di- and 3-O-methyl-D-galactose, and also part of the 3-O-methyl-L-galactose acting as side stubs. These results show that, although the main features of the corallinean xylogalactans are common to all the species studied, each one has minor characteristics of its own.

Unconventional Methyl Galactan Synthesized via the Thexyldimethylsilyl Intermediate: Preparation, Characterization, and Properties

Reaction of a beta-(1 --> 4) linked galactan with TDMS chloride followed by methylation and desilylation yields methyl galactans with unconventional functionalization patterns. The products were characterized via FTIR and NMR of the intact polymer and by CE after controlled depolymerization. A TDMS-derivatized methyl galactan contains differently methylated secondary hydroxyl groups. SEC and analytical ultracentrifugation showed a consistent decrease in the molecular weight after the consecutive reaction steps. Biological studies revealed that the methyl galactans are less active in complement fixation assays as compared with a 3-O-methyl galactan-enriched polysaccharide fraction isolated from Acanthus ebracteatus.

Purification and Partial Characterization of an Acidic Polysaccharide with Complement Fixing Ability from the Stems of Avicennia Marina

An acidic polysaccharide fraction that had high anticomplementary activity was isolated from the stems of Grey Mangrove in 0.15% yield. The final fractions was designated HAM-3-IIb-II. The polysaccharide fraction appeared to be homogenous by high performance size exclusion chromatography with an estimated molecular weight of 105 kDa. The isolated polysaccharide is more effective than polysaccharide K (PSK) in its anticomplementary activity at 58 microg/ml of PSK and 23 microg/ml of HAM-3-IIb-II that inhibit 50% of complement activity in the complement fixation assay. Structural studies indicated that HAM-3-IIb-II was rich in galacturonic acid along with arabinose, galactose and rhamnose, characterizing a pectin-type polysaccharide, which was also confirmed by FT-IR spectrum. The presence of rich neutral sugar side chains of arabinogalactans may have contributed to the expression of high activity. Traditionally, this mangrove plant is used for medicinal purposes and it appears to have some scientific applications.

Polysaccharide biological response modifiers

Biological response modifiers (BRMs) are substances which augment immune response. BRMs can be cytokines which are produced endogenously in our body by immune cells or derivatives of bacteria, fungi, brown algae, Aloe vera and photosynthetic plants. Such exogeneous derivatives (exogeneous BRMs) can be nucleic acid (CpG), lipid (lipotechoic acid), protein or polysaccharide in nature. The receptors for these exogeneous BRMs are pattern recognition receptors. The binding of exogeneous BRMs to pattern recognition receptors triggers immune response. Exogenous BRMs have been reported to have anti-viral, anti-bacterial, anti-fungal, anti-parasitic, and anti-tumor activities. Among different exogeneous BRMs, polysaccharide BRMs have the widest occurrence in nature. Some polysaccharide BRMs have been tested for their therapeutic properties in human clinical trials. An overview of current understandings of polysaccharide BRMs is summarized in this review.

A complement fixing polysaccharide from Biophytum petersianum Klotzsch, a medicinal plant from Mali, West Africa

Biophytum petersianum Klotzsch (syn. Biophytum sensitivum (L.) DC) is a medicinal plant having a traditional use, among others, as a wound healing remedy in Mali and other countries. As a water extract of the aerial parts of the plant is a frequently used preparation, we decided to look for a bioactive polysaccharide in this extract. One of the obtained polysaccharide fractions, BP100 III, isolated from a 100 degrees C water extract from the aerial parts of B. petersianum and having a monosaccharide composition typical for pectic substances, was shown to exhibit potent dose-dependent complement fixating activity. The BP100 III fraction was subjected to degradation by endo-alpha-d-(1-->4)-polygalacturonase, and three fractions were obtained by gel filtration. The highest molecular weight fraction, BP100 III.1, had a more potent activity in the complement test system than the native polymer, while the two lower molecular weight fractions were less active than the native polymer. The major part of BP100 III.1 consists of galacturonic acid and rhamnose, with branches being present on both the rhamnose and galacturonic acid residues. Arabinogalactan type II is also present in the polymer, indicating that BP100 III.1 has a structure typical of the hairy region of pectins. The major part of the two other fractions is a galacturonan, containing a strikingly high number of branch points, some to which xylose is attached. These results indicate that the pectic substance in B. petersianum contains both rhamnogalacturonan and xylogalacturonan regions.