Structural characterization and hypoglycemic effects of arabinogalactan-protein from the tuberous cortex of the white-skinned sweet potato (Ipomoea batatas L.)

Determination of starch digestibility in white sweet potato after acid hydrolysis and heat-moisture treatment using terahertz spectroscopy

Acid hydrolysis and heat-moisture treatment (HMT) have been used to alter digestibility of starch in white sweet potato, providing health benefits. The potential of terahertz spectroscopy for rapid and non-destructive determination of starch digestibility in white sweet potato treated with acetic acid and citric acid, followed by HMT, was investigated. An in vitro starch digestibility assay was employed to measure the contents of rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS). The intensities of the peaks attributed to covalent vibrational modes at 9.0, 10.5, and 13.1 THz showed a strong correlation with RDS content (R2 > 0.95). Moreover, the intensities of the peaks sensitive to non-covalent forces within and between double helices of starch, around 5.0 and 7.9 THz, were correlated with RS content (R2 > 0.65). These results indicate, after acid hydrolysis and HMT, the starch digestibility of white sweet potato can be determined using THz peaks.

Structural characteristics and anti-tumor activities of a novel polysaccharide from Klebsiella sp. SXW12

The purpose of this study is to elucidate the structure and biological properties of an extracellular polysaccharide (EPS), named EPS12, produced by Klebsiella sp. SXW12, a strain isolated from pond sludge. The maximum EPS12 yield of 15 g/L was obtained after optimizing the fermentation conditions by single-factor effects. EPS12 was an acidic homogeneous polysaccharide, and the molecular weight was measured to be 9.39 × 104 Da. Monosaccharide composition, methylation analysis, and NMR showed that EPS12 backbone was →3)-β-D-Glcp-(1 → 4)-β-D-GlcpA-(1 → 4) -α-L-Fucp-(1→, and terminal-β-D-Glcp was connected to the O-4 of →3)-β-D-Glcp-(1→. Network pharmacology analysis suggested that EPS12 may have anti-cancer effects. The anti-tumor effect of EPS12 on LLC-LUC tumor mice was studied. The results indicated that EPS12 exhibited excellent anti-tumor activity in mice at low doses (1, 2, and 4 mg/kg body weight). In vivo, EPS12 increased spleen index, promoted lymphocyte proliferation, and reduced spleen cell apoptosis through the Bcl-2-Bax/Bak-Caspase-3 apoptotic signaling pathway, and exhibited good biosafety. In addition, EPS12 could partially regulate the metabolic profiles of splenocytes. These properties make EPS12 a potential efficient and cost-effective anti-tumor agent or health product.

Unveiling the Antiobesity Mechanism of Sweet Potato Extract by Microbiome, Transcriptome, and Metabolome Analyses in Mice

This study aimed to elucidate the antiobesity mechanisms of sweet potato extract (SPE) through biochemical, gut microbiome, liver transcriptome, and metabolome analyses. Administration of SPE to high-fat-diet-fed mice significantly reduced body weight gain, serum low-density lipoprotein cholesterol, hepatic lipid accumulation, and adipocyte hypertrophy, which were closely linked to gut microbiome composition. SPE notably increased the abundance of Eubacterium_coprostanoligenes_group_unclassified and decreased that of Kineothrix, both of which were strongly associated with short-chain fatty acid (SCFA) production. LC-QTOF-MS analysis identified resin glycoside compounds from SPE with reduced levels in mouse feces, suggesting their utilization in vivo. SPE also promoted dietary fat excretion. Liver transcriptomic and metabolomic profiling revealed that SPE may exert antiobesity effects by modulating the bile-sphingolipid metabolism, which was closely correlated with the reshaped gut microbiomes and SCFAs. These findings provide new insights into the antiobesity effects and mechanisms of SPE.

Advance in Cistanche deserticola Y. C. Ma. polysaccharides: Isolation, structural characterization, bioactivities and application: A review

Cistanche deserticola Y. C. Ma (CD), is mainly distributed in the regions of China (Xinjiang, Inner Mongolia, Gansu), Mongolia, Iran and India. Cistanche deserticola polysaccharide (CDPs), as one of the main components and a crucial bioactive substance of CD, has a variety of pharmacological activities, including immunomodulatory, anti-aging, anti-oxidant, hepatoprotective, anti-osteoporotic, anti-inflammatory, intestinal flora regulatory effects. Many polysaccharides have been successfully obtained in the last three decades from CD. However, there is currently no comprehensive review available concerning CDPs. Considering the importance of CDPs for biological study and drug discovery, the present review aims to systematically summarize the recent major studies on extraction and purification methods of polysaccharides from CD, as well as the characterization of their chemical structure, biological activity, structure-activity relationship, and the application of CDPs in pharmaceutical field. Meanwhile, the shortcomings of CDPs research are further discussed in detail, and new valuable insights for future CDPs research as therapeutic agents and functional foods are proposed.

Recent insights into the physicochemical properties, bioactivities and their relationship of tea polysaccharides

Tea polysaccharides (TPS) is receiving global concern in past years due to their therapeutic effects in many diseases such as obesity and diabetes. Many publications imply that the unique physicochemical properties and bioactivities of TPS are prerequisites for its use as a biofilm, drug carrier and emulsifier. Despite numerous healthy benefits, studies on the in-deep structure-activity relationship of TPS still not well explored and explained yet. The main reasons for the research limitation are attributed mainly to the unbreakable advanced structural research technology and the formation of TPS conjugates. The present review also summarizes some similar parameters in primary structure of TPS with better bioactivities, discusses the relationships between their physicochemical properties and bioactivities, and suggests that function-specific TPS would be obtained in the future if the links between preparation methods, physicochemical properties and bioactivities of TPS could be well understood and established.

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.

White-skinned sweet potato (Ipomoea batatas L.) acutely suppresses postprandial blood glucose elevation by improving insulin sensitivity in normal rats

Long-term administration of Ipomoea batatas L. (white-skinned sweet potato, WSSP) has been reported to help manage type 2 diabetes mellitus (T2DM) in humans and animals; however, the mechanisms of blood glucose regulation by WSSP remain unclear. Therefore, we aimed to investigate the acute effects of WSSP on blood glucose homeostasis under normal conditions and the underlying mechanisms. Three fractions of WSSP (≤10, 10-50, and >50 kDa) were obtained via ultracentrifugation. Rats were subjected to an oral glucose tolerance test (OGTT) after a single administration of WSSP. The insulin tolerance test (ITT) and pyruvate tolerance test (PTT) were performed to evaluate insulin sensitivity and gluconeogenesis, respectively. Single WSSP administration markedly reduced blood glucose levels as revealed by the OGTT. Serum insulin levels were not increased by WSSP treatment. Blood glucose levels during ITT were significantly reduced due to WSSP treatment. WSSP treatment activated the phosphorylation of Akt, thereby activating insulin signaling in the skeletal muscles and liver. The ≤10 kDa fraction considerably reduced blood glucose levels per the OGTT and ITT. In contrast, gluconeogenesis in PTT and the expression of key enzymes in hepatocytes were suppressed by the >50 kDa fraction. This study demonstrated that WSSP acutely reduced postprandial blood glucose levels by improving insulin sensitivity in skeletal muscles in normal rats, which was attributed to constituents with a molecular weight of ≤10 kDa. Moreover, WSSP treatment suppressed gluconeogenesis in the liver, for which constituents of >50 kDa were responsible. Thus, WSSP can acutely regulate blood glucose homeostasis via multiple mechanisms. Since postprandial hyperglycemia leads to the onset of T2DM, WSSP, as a functional food, may possess potential active compounds that prevent T2DM.

Interaction between four galactans with different structural characteristics and gut microbiota

Human gut microbiota played a key role in maintaining and regulating host health. Gut microbiota composition could be altered by daily diet and related nutrients. Diet polysaccharide, an important dietary nutrient, was one kind of biological macromolecules linked by the glycosidic bonds. Galactans were widely used in foods due to their gelling, thickening and stabilizing properties. Recently, effects of different galactans on gut microbiota have attracted much attention. This review described the structural characteristics of 4 kinds of galactans, including porphyran, agarose, carrageenan, and arabinogalactan, along with the effects of different galactans on gut microbiota and production of short-chain fatty acids. The ability of gut microbiota to utilize galactans with different structural characteristics and related degradation mechanism were also summarized. All these four galactans could be used by gut Bacteroides. Besides, the porphyran could be utilized by Lactobacillus and Bifidobacterium, while the arabinogalactan could be utilized by Lactobacillus, Bifidobacterium and Roseburia. Four galactans with significant difference in molecular weight/degree of polymerization, glycosidic linkage, esterification, branching and monosaccharide composition required gut microbes which could utilize them have corresponding genes encoding the corresponding enzymes for decomposition. This review could help to understand the relationship between galactans with different structural characteristics and gut microbiota, and provide information for potential use of galactans as functional foods.

Plants arabinogalactans: From structures to physico-chemical and biological properties

Arabinogalactans (AGs) are plant heteropolysaccharides with complex structures occasionally attached to proteins (AGPs). AGs in cell matrix of different parts of plant are freely available or chemically bound to pectin rhamnogalactan. Type I with predominantly β-d-(1 → 4)-galactan and type II with β-d-(1 → 3) and/or (1 → 6)-galactan structural backbones construct the two main groups of AGs. In the current review, the chemical structure of AGs is firstly discussed focusing on non-traditional plant sources and not including well known industrial gums. After that, processes for their extraction and purification are considered and finally their techno-functional and biological properties are highlighted. The role of AG structure and function on health advantages such as anti-tumor, antioxidant, anti-ulcer- anti-diabetic and other activites and also the immunomodulatory effects on in-vivo model systems are overviewed.

A review on the hypoglycemic properties of selected non-leafy vegetables in Malaysia

Purpose

Non-communicable diseases such as type 2 diabetes, hypertension, cancers and cardiovascular diseases have become a major health concern globally. As literature claims that frequent consumption of fruits and vegetables can delay the onset of type 2 diabetes and its complications, this paper aims to evaluate the potential hypoglycemic properties in five types of non-leafy vegetables (pumpkin, sweet potato, bitter gourd, onion and lady’s finger), which are commonly available in Malaysia.

Design/methodology/approach

Articles were identified through several main search engines, including Pubmed, Google Scholar, Taylor and Francis Online, EDS, Wiley, ScienceDirect and Scopus. The search was limited to selected keywords to refine the outcome.

Findings

All the five types of non-leafy vegetables demonstrate hypoglycemic properties to some extent. Emerging findings indicate that there are several phytonutrients in the non-leafy vegetables contributing to the hypoglycemic effects. To date, the underlying mechanism of action remains to be elucidated, although a number of potential mechanisms of action have been proposed in the literature.

Originality/value

This review provides some insights into the hypoglycemic properties in non-leafy vegetables. In addition, phytonutrients that are responsible for the hypoglycemic effects and their mechanism of action are also highlighted.

Evaluation of white sweet potato tube-feeding formula in elderly diabetic patients: a randomized controlled trial

BACKGROUND

Elderly people with type 2 diabetes mellitus (T2DM) have an increased risk of diabetes-related microvascular and macrovascular complications, thus diabetic patients with a functioning gastrointestinal tract but without sufficient oral intake require enteral nutrition (EN) formulas to control blood glucose. White sweet potato (WSP) was a kind of sweet potato could provide a healthy carbohydrate source to EN formula. The aim of this study was to examine at risk of malnutrition T2DM patients whether a WSP-EN would attenuate glucose response and elevate nutritional index compared to a standard polymeric formulas.

METHODS

In this randomized, parallel, placebo-controlled, pilot clinical trial to investigate the effects of EN with WSP on aged residents with T2DM in long-term care institutions. In total, 54 eligible participants were randomly assigned to either the non-WSP-EN or WSP-EN group. For 60 days, the WSP-EN group received a WSP formula through nasogastric tube via a stoma with a large-bore syringe. The participants received EN of standard polymeric formulas without WSP in the non-WSP-EN group.

RESULTS

The body weight, body mass index, Mini Nutritional Assessment score, and Geriatric Nutritional Risk Index were significantly higher in the WSP-EN group (p < 0.05). Moreover, the WSP-EN intervention reduced glycated hemoglobin levels (6.73% ± 1.47% vs. 6.40% ± 1.16%), but increased transferrin (223.06 ± 38.85 vs. 245.85 ± 46.08 mg/dL), high-density lipoprotein cholesterol (42.13 ± 10.56 vs. 44.25 ± 8.43 mg/dL), and vitamin A (2.45 ± 0.77 vs 2.74 ± 0.93 μM) levels (p < 0.05). In addition, there was no important side effects including gastrointestinal intolerance with prescribed doses in our WSP-EN treated patients when compared with control ones.

CONCLUSIONS

The results suggest WSP incorporated into enteral formulas can improve nutrition status and glycemic control in elderly diabetic patients.

TRIAL REGISTRATION

NCT02711839, registered 27 May 2015.

Degradation of plant arabinogalactan proteins by intestinal bacteria: characteristics and functions of the enzymes involved

Arabinogalactan proteins (AGPs) are complex plant proteoglycans that function as dietary fiber utilized by human intestinal bacteria such as Bifidobacterium and Bacteroides species. However, the degradative mechanism is unknown because of the complexity of sugar chains of AGPs as well as variation among plant species and organs. Recently, AGP degradative enzymes have been characterized in Bifidobacterium and Bacteroides species. In this review, we summarize the characteristics and functions of AGP degradative enzymes in human intestinal bacteria.

White Sweet Potato as Meal Replacement for Overweight White-Collar Workers: A Randomized Controlled Trial

Overweight and obesity are a global concern. Meal replacements (MRs) are portion- and calorie-controlled meals, which make the food environment part of an individual's weight loss regimen. White sweet potato (WSP; Ipomoea batatas L.), used in traditional medicine in Brazil, Japan, and Taiwan, is a healthy carbohydrate source. In this randomized controlled trial, we assessed the effects of a WSP formula on body weight management in 58 white-collar workers through MR to elucidate the effects of this WSP-MR on factors leading to overweight. The participants consumed either two packs a day for a total of 132 g of WSP (WSP-MR group) or a normal diet daily (non-WSP group) for eight weeks. After eight weeks, body weight, body fat, body mass index, wrist circumference, thigh circumference, calf circumference, mid-arm circumference, and triceps skinfolds decreased significantly in both the groups. Moreover, the WSP-MR group demonstrated a 5% decrease in body weight, body fat, body mass index, and mid-arm circumference and a 3.5% decrease in glycated hemoglobin levels (p < 0.05). The treatment was well tolerated, without side effects or adverse events. Thus, our WSP formula as an MR can facilitate individual weight loss and thus has commercial application in the food industry.

Degradative enzymes for type II arabinogalactan side chains in Bifidobacterium longum subsp. longum

Type II arabinogalactan (AG) is a soluble prebiotic fiber stimulating the proliferation of bifidobacteria in the human gut. Larch AG, which is comprised of type II AG, is known to be utilized as an energy source for Bifidobacterium longum subsp. longum (B. longum). We have previously characterized GH43_24 exo-β-1,3-galactanase (Bl1,3Gal) for the degradation of type II AG main chains in B. longum JCM1217. In this study, we characterized GH30_5 exo-β-1,6-galactobiohydrolase (Bl1,6Gal) and GH43_22 α-L-arabinofuranosidase (BlArafA), which are degradative enzymes for type II AG side chains in cooperation with exo-β-1,3-galactanase. The recombinant exo-β-1,6-galactobiohydrolase specifically released β-1,6-galactobiose (β-1,6-Gal₂) from the nonreducing terminal of β-1,6-galactooligosaccharides, and the recombinant α-L-arabinofuranosidase released arabinofuranose (Araf) from α-1,3-Araf-substituted β-1,6-galactooligosaccharides. β-1,6-Gal₂ was additively released from larch AG by the combined use of type II AG degradative enzymes, including Bl1,3Gal, Bl1,6Gal, and BlArafA. The gene cluster encoding the type II AG degradative enzymes is conserved in all B. longum strains, but not in other bifidobacterial species. The degradative enzymes for type II AG side chains are thought to be important for the acquisition of type II AG in B. longum.

Comparison Study on Polysaccharide Fractions from Laminaria japonica: Structural Characterization and Bile Acid Binding Capacity

Our previous study has suggested that the crude polysaccharide obtained from Laminaria japonica by acid assisted extraction (LP-A) have significant bile acid-binding capacity, which probably ascribed to its specific structure characterization. The relationship between structure characterization and bile acid-binding capacity of the purified LP-A fractions are still unknown. This paper conducted a comparison study on the structure characterization and bile acid-binding capacity of three LP-A fractions (LP-A4, LP-A6, and LP-A8). The results indicated that LP-A4, LP-A6, and LP-A8, characterized as mannoglucan, fucomannoglucan, and fucogalactan, had significantly different structure characterization. Furthermore, the bile acid-binding capacity of LP-A8 was obviously higher than the other fractions, which may be attributed to its highly branched structure, abundant sulfate, fucose, and galactose in chemical composition and denser interconnected macromolecule network in molecular morphology. This study provides scientific evidence for the potential utilization of LP-A8 as an attractive functional food supplement candidate for the hyperlipidemia population.

A novel α-galactosidase from Fusarium oxysporum and its application in determining the structure of the gum arabic side chain

We previously reported that Fusarium oxysporum 12S produces two bifunctional proteins, FoAP1 and FoAP2, with α-d-galactopyranosidase (GPase) and β-l-arabinopyranosidase (APase) activities. The aim of this paper was to purify a third GPase, FoGP1, from culture supernatant of F. oxysporum 12S, to characterize it, and to determine its mode of action towards gum arabic. A cDNA encoding FoGP1 was cloned and the protein was overexpressed in Escherichia coli. Module sequence analysis revealed the presence of a GH27 domain in FoGP1. The recombinant enzyme (rFoGP1) showed a GPase/APase activity ratio of 330, which was quite different from that of FoAP1 (1.7) and FoAP2 (0.2). Among the natural substrates tested, rFoGP1 showed the highest activity towards gum arabic. In contrast to other well-characterized GPases, rFoGP1 released a small amount of galactose from α-galactosyl oligosaccharides such as raffinose and exhibited no activity toward galactomannans, which are highly substituted with α-galactosyl side chains. This indicated that FoGP1 is an unusual type of GPase. rFoGP1 released 30% of the total galactose from gum arabic, suggesting the existence of a large number of α-galactosyl residues at the non-reducing ends of gum arabic side chains. Together, rFoGP1 and α-l-arabinofuranosidase released four times more arabinose than α-l-arabinofuranosidase acting alone. This suggested that a large number of α-l-arabinofuranosyl residues is capped by α-galactosyl residues. ¹H NMR experiments revealed that rFoGP1 hydrolyzed the α-1,3-galactosidic linkage within the side chain structure of [α-d-Galp-(1→3)-α-l-Araf-(1→] in gum arabic. In conclusion, rFoGP1 is highly active toward α-1,3-galactosyl linkages but negligibly or not active toward α-1,6-galactosyl linkages. The novel FoGP1 might be used to modify the physical properties of gum arabic, which is an industrially important polysaccharide used as an emulsion stabilizer and coating agent.

Hypolipidemic effects of crude green tea polysaccharide on rats, and structural features of tea polysaccharides isolated from the crude polysaccharide

Crude tea polysaccharide (crude TPS) was prepared from instant green tea by ethanol precipitation followed by ultrafiltration membrane treatment and its effects on blood lipid, liver lipid, and fecal lipid levels were examined with Sprague-Dawley rats fed a high-fat diet. Although crude TPS showed no effects on the serum lipid levels, it suppressed the liver lipid accumulation and increased the fecal excretion of dietary fat. Then, the structural features of crude TPS were investigated. After separation of crude TPS by DEAE-cellulose and gel-filtration column chromatography, two kinds of neutral tea polysaccharides (NTPS-LP and NTPS-HH) and an acidic polysaccharide (ATPS-MH) were obtained. According to monosaccharide composition, methylation, and NMR analyses, NTPS-LP, NPTS-HH, and ATPS-MH were presumed to be starch, arabinogalactan with β-1,3-linked galactosyl backbone blanched at position 6 and with 1,5-linked arabinofuranosyl residues, and α-1,4-linked galacturonic acid backbone with arabinogalactan region, respectively.

Chemical constituents and health effects of sweet potato

Sweet potatoes are becoming a research focus in recent years due to their unique nutritional and functional properties. Bioactive carbohydrates, proteins, lipids, carotenoids, anthocyanins, conjugated phenolic acids, and minerals represent versatile nutrients in different parts (tubers, leaves, stems, and stalks) of sweet potato. The unique composition of sweet potato contributes to their various health benefits, such as antioxidative, hepatoprotective, antiinflammatory, antitumor, antidiabetic, antimicrobial, antiobesity, antiaging effects. Factors affecting the nutritional composition and bio-functions of sweet potato include the varieties, plant parts, extraction time and solvents, postharvest storage, and processing. The assays for bio-function evaluation also contribute to the variations among different studies. This review summarizes the current knowledge of the chemical composition of sweet potato, and their bio-functions studied in vitro and in vivo. Leaves, stems, and stalks of sweet potato remain much underutilized on commercial levels. Sweet potato can be further developed as a sustainable crop for diverse nutritionally enhanced and value-added food products to promote human health.

Polysaccharides from Moringa oleifera gum: structural elements, interaction with β-lactoglobulin and antioxidative activity

Structural highlights of an antioxidative arabinogalactan from Moringa oleifera gum that interacts with β-lactoglobulin.

Isolation and structural elements of a water-soluble free radical scavenger from Nyctanthes arbor-tristis leaves

The leaves of Nyctanthes arbor-tristis L. (Oleaceae) are used in Ayurvedic medicine for the management of a range of diseases, but reports on its phytochemicals and pharmacological properties are inadequate. Herein, we report purification of an antioxidative polysaccharide (F2) extracted from its leaves by water. The presence of a highly branched polysaccharide (75 kDa) containing esterified phenolic acids was revealed by chemical, chromatographic and spectroscopic analyses. Particularly, ESMS analysis of per acetylated oligomeric fragments derived by Smith degradation provides important structural information on a spectrum of glycerol tagged oligosaccharides. This polysaccharide showed dose dependent free radical scavenging capacity as evidenced by DPPH and Ferric reducing power assay. This pharmacologically active compound (F2) formed a water soluble complex with bovine serum albumin over pH 4.0-7.4. Accordingly, traditional aqueous extraction method provides a molecular entity that induces a pharmacological effect: this could epitomize a smart approach in phytotherapeutic management.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: an update for 2009-2010

This review is the sixth update of the original article published in 1999 on the application of MALDI mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2010. General aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, arrays and fragmentation are covered in the first part of the review and applications to various structural typed constitutes the remainder. The main groups of compound that are discussed in this section are oligo and polysaccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals. Many of these applications are presented in tabular form. Also discussed are medical and industrial applications of the technique, studies of enzyme reactions and applications to chemical synthesis.

Immune activity of sweet potato (Ipomoea batatas L.) glycoprotein after enzymatic and chemical modifications

Immune activity of SPG-1 after its protein or carbohydrate portions modified by enzymatic or chemical treatments. Note: a and b: P < 0.01 and 0.05 compared with NC group, respectivily; c and d: P < 0.01 and 0.05 compared with untreated group, respectivily.

In vivo antitussive activity of a pectic arabinogalactan isolated from Solanum virginianum L. in Guinea pigs

ETHNOPHARMACOLOGICAL RELEVANCE

Solanum virginianum L. is used for the management of fever, bronchial asthma and cough for thousands of years. While the link to a particular indication has been established in human, the active principle of the formulation remains unknown. Herein, we have investigated a polysaccharide isolated from its leaves.

MATERIALS AND METHODS

Utilizing traditional aqueous extraction protocol and using chemical, chromatographic, spectroscopic and biological methods we have analysed an antitussive pectic arabinogalactan isolated from its leaves.

RESULTS

The water extracted polymer (WEP) is a highly branched arabinogalactan containing, inter alia, (1,3)-, (1,6)- and (1,3,6)-linked β-Galp residues, terminal-, (1,5)- and (1,3,5)-linked units of α-Araf together with (1,2)- and (1,2,4)-linked Rhap. In vivo investigation on the citric-acid induced cough efforts in guinea pigs shows that the antitussive activity of the orally administered pectic arabinogalactan is greater than codeine phosphate. Remarkably, this macromolecule neither altered specific airway smooth muscle reactivity significantly nor it induced considerable change on levels of NO in expiratory flow in guinea pigs.

CONCLUSIONS

Thus, traditional aqueous extraction method provides a molecular entity, which induces antitussive activity without addiction: this could represent an attractive approach in phytotherapeutic management.

Structure Characterization and Adhesive Ability of a Polysaccharide from Tendrils of Parthenocissus heterophylla

In order to reveal the structure of the polysaccharide and its contribution to the biological adhesion system of Parthenocissus heterophylla, a water-soluble polysaccharide (PT-A) was isolated from tendrils using DEAE-cellulose and Sephadex G-100 columns. PT-A mainly consisted of a backbone of (1→3)-linked-β-D-Galp residues and substituted at O-6 with side chains of (1→5)-linked-α-L-Ara f residues and glucomannopyranosyl residues. Individual polysaccharide chains of PT-A with the approximately height of 0.75 nm were observed by AFM. The analysis of force curves indicated that PT-A was a kind of elastic polysaccharide with a maximum adhesion force of 279.98 nN, which could be applied as a potential bio-adhesive.

Antitussive Activity of the Water-Extracted Carbohydrate Polymer from Terminalia chebula on Citric Acid-Induced Cough

Terminalia chebula, a medicinal plant, is widely used in the management of various diseases. As the water extract of its dried ripe fruit is a frequently used preparation, we decided to look for bioactive polysaccharide in this extract. We demonstrate that the obtained polysaccharide fraction, CP, contained a highly branched arabinogalactan protein having a (1 → 3)-, (1 → 6)- and (1 → 3, 6)-linked β-D-Galp together with (1 → 5)- and (1 → 3)-linked α-L-Araf and nonreducing end units of α-L-Araf. This polymer possesses strong antitussive property. Our results showed that the number of citric acid-induced cough efforts decreased significantly after the oral application of polysaccharide fraction in a dose of 50 mg kg⁻¹ body weight. Its antitussive efficacy was higher than cough suppressive effect of standard drug codeine. Therefore, traditional aqueous extraction method provides a major polysaccharide, which induces a pharmacological effect: this could represent an attractive approach in phytotherapeutic managements.

The effects of an arabinogalactan-protein from the white-skinned sweet potato (Ipomoea batatas L.) on blood glucose in spontaneous diabetic mice

We examined the effects of an arabinogalactanprotein (WSSP-AGP) from Ipomoea batatas L. on hyperglycemia in db/db mice. An oral glucose tolerance test indicated significantly decreased plasma glucose levels by WSSP-AGP. Additionally, an insulin tolerance test found improvement in insulin sensitivity due to treatment with WSSP-AGP. This suggests that amelioration of insulin resistance by WSSP-AGP causes to lead its hypoglycemic effects.