Isolation and structure characterization of glucuronoxylans from Dolichos lablab L. hull

Botany, traditional uses, phytochemistry, pharmacology, edible uses, and quality control of Lablab Semen Album: A systematic review

ETHNOPHARMACOLOGICAL RELEVANCE

Lablab Semen Album (lablab), the white and dried mature fruit of Lablab purpureus in the Lablab genus of the Fabaceae family, is a renowned traditional medicinal herb with a long history of use in China. In Chinese medicine, lablab is often combined with other drugs to treat conditions such as weak spleen and stomach, loss of appetite, loose stools, excessive leucorrhoea, summer dampness and diarrhea, chest tightness, and abdominal distension.

MATERIALS AND METHODS

Comprehensive information on lablab was gathered from databases including Web of Science, Science Direct, Google Scholar, Springer, PubMed, CNKI, Wanfang, and ancient materia medica.

RESULTS

Lablab, a member of the lentil family, thrives in warm and humid climates, and is distributed across tropical and subtropical regions worldwide. Traditionally, lablab is used to treat various ailments, such as spleen and stomach weakness, loss of appetite, and diarrhea. Phytochemical analyses reveal that lablab is a rich source of triterpenoid saponins, glucosides, volatile oils, polysaccharides, and amino acids. Lablab extracts exhibit diverse biological activities, including hypolipidemic, hypoglycemic, immunomodulatory, antioxidant, hepatoprotective, antitumoral, antiviral properties, and more. Besides its medicinal applications, lablab is extensively used in the food industry due to its high nutrient content. Additionally, the quality of lablab can be regulated by determining the levels of key chemical components pivotal to its medicinal effects, ensuring the herb's overall quality.

CONCLUSION

Lablab is a promising medicinal and edible plant ingredient with diverse pharmacological effects, making it a valuable ingredient for food, pharmaceuticals, and animal husbandry. However, it has inherent toxicity if not properly prepared. Additionally, some traditional uses and pharmacological activities lack scientific validation due to incomplete methods, unclear results, and insufficient clinical data. Thus, further in vivo and in vitro studies on its pharmacology, pharmacokinetics, and toxicology, along with clinical efficacy evaluations, are needed to ensure lablab's safety and effectiveness. As an important traditional Chinese medicine, lablab deserves more attention.

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

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

A novel substitution pattern in glucuronoarabinoxylans from woody bamboos

(1 → 4)-β-D-Xylans are the second most abundant plant biopolymers on Earth after cellulose. Although their structures have been extensively studied, and industrial applications have been found for them and their derivatives, they are still investigated due to the diversity of their structures and uses. In this work, hemicellulose fractions obtained previously with 1 M KOH from two species of woody bamboos, Phyllostachys aurea and Guadua chacoensis, were purified, and the structures of the glucuronoarabinoxylans (GAX) were studied by chemical and spectroscopic methods. In both cases, major amounts of α-L-arabinofuranose residues were linked to C3 of the xylose units of the backbone, and also α-D-glucuronic acid residues and their 4-O-methyl-derivatives were detected in minor quantities, linked to C2 of some xylose residues. Methylation analysis of the carboxyl-reduced derivative from GAX from P. aurea indicated the presence of terminal and 5-linked arabinofuranose units. NMR spectroscopy showed the presence of disaccharidic side chains of 5-O-α-l-arabinofuranosyl-L-arabinofuranose for the GAX from P. aurea, while for those of G. chacoensis, only single side chains were found. To the best of our knowledge, this disaccharide was not found before as side chain of xylans.

Purification, characterization and bioactivities of a 4-O-methylglucuronoxylan from Aralia echinocaulis

The discovery of active constituents from food plants is an important area of research in pharmaceutical sciences. Aralia echinocaulis is a medicinal food plant that is mainly used to prevent or treat rheumatoid arthritis in China. This paper reported the isolation, purification and bioactivity of a polysaccharide (HSM-1-1) from A. echinocaulis. Its structural features were analyzed according to the molecular weight distribution, monosaccharide composition, gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance spectra. The results indicated that HSM-1-1 was a new 4-O-methylglucuronoxylan mainly composed of xylan and 4-O-methyl glucuronic acid with the molecular weight of 1.6 × 10⁴ Da. Furthermore, the antitumor and anti-inflammatory activities of HSM-1-1 in vitro were investigated, and the results showed that HSM-1-1 had potent proliferation inhibition activity on colon cancer cell SW480 with an inhibition rate of 17.57 ± 1.03 % at a concentration of 600 μg/mL, as measured via MTS methods. To our knowledge, this is the first report of a polysaccharide structure obtained from A. echinocaulis and its bioactivities, and its potential as an adjuvant natural product with antitumor effects is shown.

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 characteristics of three pectins isolated from white kidney bean

Three water-soluble pectic polysaccharides (WKBP-P2, P3 and P4) were isolated from white kidney bean by ion exchange combined with size-exclusion methods. The structural features were characterized by GC-MS, NMR spectroscopy and HPSEC-MALLS-RI. It was found that three pectic polysaccharides were the major water-extracted polysaccharides in white kidney bean. All the WKBP-P2, P3 and P4 were probably composed of various structural regions including homogalacturonan (HG), xylogalacturonan (XGA), rhamnogalacturonan I (RG-I) regions in backbone, and arabinan region mainly as side chain. However, these pectic polysaccharides were significantly different in molar ratios of these structural regions and molecular size. WKBP-P2 was HG-predominant pectin (partially methyl-esterified) with weight-average molecular weight (M_w) of 1.2 × 10⁴ g/mol, and contained minor RG-I, arabinan and probable XGA regions. WKBP-P3 (M_w of 4.0 × 10⁴ g/mol) primarily embraced XGA, HG, arabinan regions and minor RG-I region. WKBP-4 with highest M_w (4.5 × 10⁵ g/mol) had the most arabinan region (51.3%), which was probably the side chain linked to the backbone composed of RG-I, HG and slight XGA regions. These findings provided a structural basis for study on polysaccharides from white kidney bean, which was benefit for development of functional food.