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Concept: Dioscorea

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Abstract Twenty-three phenolic compounds were isolated from Dioscorea opposita by bioactivity-guided method and their inhibitory effect against pancreatic lipase was evaluated. A total of 15 isolates reduced lipase activity at IC(50) values of less than 50 µM and 3,3',5-trihydroxy-2'-methoxybibenzyl showed the highest inhibition with an IC(50) value of 8.8 µM. This study is a first to reveal the pancreatic lipase inhibitory activity by both D. opposita and its isolated compounds.

Concepts: Enzyme, Tropical agriculture, Value, Lipase, Pancreatic lipase, Yam, Dioscorea, Dioscorea opposita

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The yam (Dioscorea opposita Thunb) is a well-known edible food and widely used as the traditional Chinese medicine. The present investigation was designed to evaluate the immunomodulatory activity of glycoprotein (DOT) from yam and explore its possible molecular mechanisms. Results showed that the DOT could improve the cell immunity, humoral immunity and phagocytic system function of the normal mice. The DOT could also increase the production of TNF-α, interleukin-6 and nitric oxide and enhance the pinocytosis function of macrophages. Furthermore, the DOT increased phosphor-p38, JNK, ERK1/2 and nuclear factor kappa B (NF-κB) p65 protein expression in peritoneal macrophages. Taken together, our data suggest that DOT could be used as a potential immunostimulant and exert its immunomodulatory activity via mitogen-activated protein kinases and NF-κB signal pathways. Copyright © 2017 John Wiley & Sons, Ltd.

Concepts: Immune system, Antibody, Signal transduction, Immunology, Humoral immunity, Yam, Dioscorea, Dioscorea opposita

0

Fifteen steroidal saponins 1-15, which include 4 furostanol glycosides 1-3 and 15, and 11 spirostanol glycosides 4-14, were isolated from the tubers and leaves of lesser yam (Dioscorea esculenta, Togedokoro). Their structures were identified by nuclear magnetic resonance and liquid chromatography mass spectroscopy. Four steroidal saponins 9, 11, 14, and 15 were found to be novel compounds.

Concepts: Spin, Nuclear magnetic resonance, Analytical chemistry, Yam, Dioscorea, Dioscorea esculenta

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Three new Chinese yam polysaccharides (namely HSY, huaishanyao in Chinese) were isolated using the methods of boiled water extraction and stepwise ethanolic precipitation, combined with the tangential flow ultrafiltration membrane system. Their molecular weights were determined by high performance gel permeation chromatography. Three type yam polysaccharides in different molecular weight were isolated: HSY-I (>50 kDa), HSY-II (10 to 50 kDa), HSY-III (<10 kDa). The monosaccharide and glycosidic bond links composition were analyzed with GC and Smith degradation. The structure characteristics were further discussed combined with infrared spectrophotometry. Dexamethasone-induced insulin resistance glucose/lipid metabolism diabetic mice model was established to evaluate the hypoglycemic effect of different concentration of HSY and different molecular weights polysaccharide HSY-I, HSY-II, and HSY-III. The results indicated that the HSY polysaccharide mixture, HSY-I and HSY-II had hypoglycemic effect.

Concepts: Water, Starch, Polysaccharide, Cellulose, Carbohydrate chemistry, Glycosidic bond, Dioscorea, Dioscorea opposita

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Numerous furanoids have been reported to be toxic, and many of them were found in herbal medicines. Toxicities of furanoids are suggested to result from the generation of cis-enedials via biotransformation. The detection of the electrophilic metabolic intermediates is a challenge. Earlier, we developed a selective approach to screen potential toxic furanoids, through which we found two major furanoids, diosbulbin B and 8-epidiosbulbin E acetate, in Dioscorea bulbifera L., a known furanoid-containing and hepatotoxic herbal medicine. In the present study, we improved the approach to analyze furanoids in D. bulbifera L., which allowed us to detect additional six potential furanoids, including diosbulbin A, diosbulbin D, diosbulbin E, diosbulbin F, diosbulbin M, and diosbulbin D glycoside. The achievements of this study enhanced the sensitivity to screen potential toxic furanoids through elevating S/N values by approximately 3 times. This will facilitate the understanding of mechanisms of toxic actions of D. bulbifera L. and other furanoid-containing toxic herbal medicines.

Concepts: Present, Time, Pharmacology, Medicine, Developed country, Toxicity, Dioscorea, Dioscorea bulbifera

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Dioscorea bulbifera or air potato has been used as a folk remedy to treat cancer. A mannose binding lectin from bulbils of Dioscorea bulbifera was purified in a single step by affinity chromatography on mucin coupled Sepharose 4B column, determined by its fine sugar specificity by glycan array analysis and studied for its clinical potential in cancer and HIV research. SDS-PAGE showed that lectin is a monomer of Mr 24kDa. DBL agglutinated only rabbit erythrocytes and was inhibited by mucin, asialomucin, fetuin, asialofetuin and transferrin but not by any monosaccharides. Glycan array analysis of DBL revealed its affinity towards high mannose N-linked glycans with enhanced affinity for terminal mannose including N-linked glycans of HIV envelope glycoprotein gp120 and has strong anti-reverse transcriptase activity. DBL showed strong binding to non metastatic human colon epithelial cancer HT 29, metastatic SW 620 and hepatocellular HepG2 cell lines. DBL showed dose and time dependent growth inhibitory effects on all the three cell lines HT 29, SW 620 and HepG2 with IC50 of 110μg, 9.8μg, 40μg respectively at 72h. Inhibitory effect of DBL was effectively blocked in presence of competing glycans like mucin. DBL has promising clinical potential both in cancer and HIV research.

Concepts: Immune system, Glycoproteins, Oncology, Carbohydrates, Glycoprotein, Yam, Dioscorea, Dioscorea bulbifera

0

Tropical starches from Dioscorea dumetorum (bitter) and Dioscorea oppositifolia (Chinese) yams were acetylated with acetic anhydride in pyridine medium and utilized as polymers for the delivery of repaglinide in microsphere formulations in comparison to ethyl cellulose. Acetylated starches of bitter and Chinese yams with degrees of substitution of 2.56 and 2.70 respectively were obtained. Acetylation was confirmed by FTIR, (1)H NMR spectroscopy. A 3(2) factorial experimental design was performed using polymer type and drug-polymer ratio as independent variables. Particle size, swelling, entrapment and time for 50% drug release (t50) were dependent variables. Contour plots showed the relationship between the independent factors and the response variables. All variables except swelling increased with drug: polymer ratio. Entrapment efficiency and was generally in the rank of Bitter yam>Ethyl cellulose>Chinese yam. Repaglinide microspheres had size 50±4.00 to 350 ±18.10μm, entrapment efficiency 75.30±3.03 to 93.10±2.75% and t50 3.20±0.42 to 7.20±0.55h. Bitter yam starch gave longer dissolution times than Chinese yam starch at all drug-polymer ratios. Drug release fitted Korsmeyer-Peppas and Hopfenberg models. Acetylated bitter and Chinese yam starches were found suitable as polymers to prolong release of repaglinide in microsphere formulations.

Concepts: Ethanol, Nuclear magnetic resonance, Starch, Hydrolysis, Acetic anhydride, Yam, Dioscorea, Dioscorea opposita

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The complete genome sequence of Chinese yam necrotic mosaic virus (ChYNMV) consisting of 8,213 nucleotides containing one open reading frame was determined by the transcriptome data generated from Discorea opposita This is the first report of the complete nucleotide sequence of ChYNMV from Dioscorea opposita in the Republic of Korea.

Concepts: DNA, Gene, Genetics, Genome, RNA, Yam, Dioscorea, Dioscorea opposita

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Rhizoma Dioscoreae Collettii, is known as Huang Dioscorea collettii, Rhizoma Coptidis Brevisepalae or yellow ginger. It is neutral in nature and bitter in taste which is described to Gan (Liver) meridian, Wei (Stomach) meridian and Pangguang (Bladder) meridian. It was often used in the treatment of chyloid stranguria, gonorrhea, leucorrhagia, rheumatism arthralgia pain, joints disable, and lumbar knee pain syndrome in clinical.

Concepts: Rheumatology, Osteoarthritis, Peritoneum, Yellow River, Dioscorea

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Context Dioscorea bulbifera L. (Dioscoreaceae) has been used in a traditional Thai longevity medicine preparation. Isolation of inhibitors from natural products is a potential source for continuous development of new HIV-1 integrase (IN) inhibitors. Objective The objective of this study is to isolate the compounds and evaluate their anti-HIV-1 IN activity, as well as to predict the potential interactions of the compounds with an IN. Materials and methods The ethyl acetate and water fractions (1-100 μg/mL) of Dioscorea bulbifera bulbils were isolated and tested for their anti-HIV-1 IN activity using the multiplate integration assay (MIA). The interactions of the active compounds with IN were investigated using a molecular docking method. Results and discussions The ethyl acetate and water fractions of Dioscorea bulbifera bulbils afforded seven compounds. Among these, allantoin (1), 2,4,3',5'-tetrahydroxybibenzyl (2), and 5,7,4'-trihydroxy-2-styrylchromone (5) were isolated for the first time from this plant. Myricetin (4) exhibited the most potent activity with an IC50 value of 3.15 μM, followed by 2,4,6,7-tetrahydroxy-9,10-dihydrophenanthrene (3, IC50 value= 14.20 μM), quercetin-3-O-β-d-glucopyranoside (6, IC50 value = 19.39 μM) and quercetin-3-O-β-d-galactopyranoside (7, IC50 value = 21.80 μM). Potential interactions of the active compounds (3, 4, 6, and 7) with the IN active site were additionally investigated. Compound 4 showed the best binding affinity to IN and formed strong interactions with various amino acid residues. These compounds interacted with Asp64, Thr66, His67, Glu92, Asp116, Gln148, Glu152, Asn155, and Lys159, which are involved in both the 3'-processing and strand transfer reactions of IN. In particular, galloyl, catechol, and sugar moieties were successful inhibitors for HIV-1 IN.

Concepts: Amino acid, Acid, Enzyme inhibitor, Chemical compound, Docking, Yam, Dioscorea, Dioscorea bulbifera