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PubMed2001

[Resources of medicinal plants from genus Dioscorea in Guizhou province].

OBJECTIVE: To gain a clear idea on the species and distribution of medicinal plants from Dioscorea in Guizhou province. METHOD: By consulting related specimens and date and carrying out identification study. RESULT: There are 17 species (including varieties) of medicinal plants from Dioscorea in Guizhou province. The distribution, growing environment and medicinal effect of these species have been clarified, and an identification index has been established. CONCLUSION: A scientific basis can be provided by this study for exploiting the medicinal plants from Dioscorea resources in Guizhou province.

China↗
PubMed2002

[Isolation and identification of steroidal saponins in total saponin from Dioscorea nipponica Makino].

AIM: To investigate the water-soluble steroidal saponins in total saponin from Dioscorea nipponica Makino and look for new active compounds. METHODS: The compounds were isolated with silica gel, PTLC and HPLC, and their structures were elucidated by acid hydrolysis, physical and chemical data and spectral analysis (IR, NMR, MS, HMQC, HMBC) as well as chemical correlations. RESULTS: The two steroidal saponins (water-insoluble saponin and water-soluble saponin) were isolated from the total saponin of Dioscorea nipponica Makino. The structures were elucidated as diosgenin 3-O-[alpha-L-rhamnopy ranosyl (1-->2)-[beta-D-glucopyranosyl(1-->3)]]-beta-D-glucopyranoside (I), diosgenin 3-O-[alpha-L-rhamnopyranosyl (1-->3)-alpha-L-rhamnopyranosyl (1-->4)-alpha-L-rhamnopyranosyl (1-->4)]-beta-D-glucopyranoside (II). CONCLUSION: Compound II is a new steroidal saponin and firstly isolated from Dioscorea nipponica Makino. It was named as dioscin Dc.

Dioscorea↗
PubMed2003

[Experimental pathological study of subacute intoxication by Dioscorea bulbifera L].

OBJECTIVE: To study the pathological change and the toxic mechanism of Dioscorea bulbifera L in mice. METHODS: Sixty ICR mice were randomly assigned to four groups poisoned respectively with 200% Dioscorea bulbifera L of 1/4 LD50, 1/10LD50, 1/30LD50 and a control group treated with distilled water by oral administration. All animals were pathologically examined with LM and some of them were examined with TEM when the mice died during the experiment or the survival mice were sacrificed after thirty days. RESULTS: The pathological changes showed fatty change and the increasing glycogen of liver cells; degeneration and necrosis of the epithelia of uriniferous tubules. The serum BUN and ALT of the experimental groups mice were higher than that of control group. Enzyme histochemical staining showed the decreasing activity of G-6-P and SDH in the liver cells in the experimental groups. CONCLUSION: The experiment suggests that the target organs were liver and kidney. The toxic mechanism of Dioscorea bublifera L was the damage of the mitochondrional and endoplasmic reticulum membrane directly. As a result, the activity of the SDH and G-6-P decreased, the metabolism was affected.

Animals↗
PubMed2006

[Study on steroidal saponins of Dioscorea septemloba thunb].

OBJECTIVE: To isolate and identify steroidal saponins from the rhizomes of Dioscorea septemloba Thunb. METHODS: The compounds were isolated by solvent extraction, column chromatography on silica gel and ODS, and their structures were elucidated on the base of chemical and spectral analyses. RESULTS: Three steroidal saponins were isolated from the rhizomes of Dioscorea septemloba Thunb, and their structures were detemined as dioscin (I), protodioscin (II), protogracillin (III). CONCLUSION: Compound II and III were obtained from the rhizomes of Dioscorea septemloba Thunb for the first time.

Dioscorea↗
PubMed2004

Protective effect of water yam (Dioscorea alata L.) extract on the copper-driven fenton reaction and X-ray induced DNA damage in vitro.

The rhizome extract of Dioscorea has been shown to possess radical scavenging activity. In this study, the protective effect of water yam (Dioscorea alata L.) rhizome extract on calf thymus DNA and plasmid DNA strand breakage by the copper-driven Fenton reaction and X-irradiation was examined. The protective activity in vitro of four lyophilized extracts obtained from yam rhizomes: (1) aqueous extract (YAE); (2) 30% ethanolic extract (YEE); (3) aqueous extract boiled for 30 min (BYAE); and (4) 30% ethanolic extract boiled for 30 min (BYEE) were evaluated by ethidium bromide binding assay and DNA nicking assay. The YAE, YEE, and BYEE effectively inhibited the copper-driven Fenton reaction-induced damage of calf thymus DNA, while inhibition was less pronounced in the case of X-ray induced strand breakage of plasmid DNA. While BYAE potently inhibited X-ray induced strand breaks in plasmid pGL3 DNA, it failed to inhibit, and even greatly enhanced copper-H(2)O(2) induced damage of calf thymus DNA. The present results demonstrate strong copper chelating and weak hydroxyl radical scavenging activities in yam rhizome extracts, and these activities may vary depending on the procedures used in preparing the extract.

Copper↗
PubMed2026

Characterization of endogenous pararetroviruses in yam (Dioscorea spp.) genomes revealed four pararetrovirus groups, including a dioscovirus-like lineage: implications for diagnostics and yam germplasm exchange.

Yams (Dioscorea spp.) are an important vegetatively propagated food security crop grown for their starchy tubers. Yams are susceptible to several viruses, and their genomes harbor a diverse array of endogenous pararetroviral sequences (EPRVs), which complicate diagnostics and germplasm exchange because of their similarity to episomal viruses. To better characterize EPRV diversity, we analyzed 86 publicly available whole-genome sequences from five Dioscorea species (D. rotundata, D. alata, D. praehensilis, D. abyssinica, and D. dumetorum). Assembled genomes were screened for endogenous pararetrovirus sequences (EPRVs) using the CAULIFINDER pipeline, targeting conserved RT/RNase H domains of the Caulimoviridae family. Our analyses revealed four major EPRV groups in D. rotundata: Yendovirus, Badnavirus, Yam Endovirus 1, and a Dioscovirus-like lineage. While most insertions were fragmented, we found full-length putative viral genomes corresponding to the Yam Badnavirus and Dioscovirus-like clades. These findings expand knowledge of yam EPRV diversity, contribute to the development of improved diagnostic tools to differentiate endogenous and episomal forms, and promote a science-based, risk-proportionate approach to yam phytosanitation that facilitates global germplasm exchange while maintaining biosecurity.

Dioscorea↗
PubMed2005

Proximate analysis and some antinutritional factor constituents in selected varieties of Jamaican yams (Dioscorea and Rajana spp.).

Two wild (Dioscorea polygonoides and Rajana cordata) and seven cultivated varieties of Jamaican yams (Dioscorea spp.) were analyzed for their proximate composition and the levels of antinutritional factors. The protein level range was 47.8 +/- 2.6 to 88.0 +/- 2.5 g/kg dry weight. The lowest level was seen in D. cayenensis. The range for the dietary fiber content in the tubers was 16.3 +/- 0.7 to 63.5 +/- 0.4 g/kg dry weight. The wild yam varieties recorded higher levels. Saponins level was <600 mg/kg dry weight in all the tubers analyzed except for bitter yam (2962.5 +/- 60.5 mg/kg dry weight). Total phenol content ranged from 1.3 +/- 0.1 to 79.3 +/- 6.1 g/kg while total condensed tannin content ranged from 0.1 +/- 0.0 to 26.7 +/- 3.8 g/kg dry weight. Samples that showed high levels of phenols also had high levels of condensed tannins. All the samples analyzed contained low levels of lectins and no alkaloids were detected. The levels of antinutritional factors did not clearly delineate the wild varieties from the edible varieties.

Dietary Fiber↗
PubMed2004

Tissue and subcellular localization of oligofurostanosides and their specific degrading beta-glucosidase in Dioscorea caucasica Lipsky.

The application of the histochemical technique using the Ehrlich reagent showed that the oligofurostanosides--the steroid glycosides of the furostan series--are localized in idioblasts (special cells--receptacles) of the epidermal layer of Dioscorea caucasica leaves. The activity of oligofurostanoside-specific beta-glucosidase was localized mainly in the membrane fraction of the thylakoides and was also found in the Dioscorea caucasica leaves. We have suggested, that the differential tissue, the subcellular localization of the oligofurostanosides and their degrading enzymes provide the maintenance of the furostanol structure of steroid glycosides which is necessary for their transport within the leaf and from the leaf to the rhizome.

Centrifugation, Density Gradient↗
PubMed2001

Antioxidant activities of dioscorin, the storage protein of yam (Dioscorea batatas Decne) tuber.

Dioscorin, the storage protein of yam (Dioscorea batatas Decne) tuber (which is different from dioscorine found in tubers of Dioscorea hirsuta), was purified to homogeneity after DE-52 ion exchange column according to the methods of Hou et al. (J. Agric. Food Chem. 1999, 47, 2168-2172). A single band of 32 kDa dioscorin was obtained on a sodium dodecyl sulfate-polyacrylamide gel electrophoresis gel with 2-mercaptoethanol treatment. This purified dioscorin was shown by spectrophotometric method to have scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical in a pH-dependent manner. There is a positive correlation between scavenging effects against DPPH (8-46%) and amounts of 32 kDa dioscorin (5.97-47.80 nmol) added in Tris-HCl buffer (pH 7.9), which are comparable to those of glutathione at the same concentrations. Using electron paramagnetic resonance (EPR) spectrometry for DPPH radical detection, it was found that the intensities of the EPR signal were decreased by 28.6 and 57 nmol of 32 kDa dioscorin in Tris-HCl buffer (pH 7.9) more than in distilled water compared to controls. EPR spectrometry was also used for hydroxyl radical detection. It was found that 32 kDa dioscorin could capture hydroxyl radical, and the intensities of the EPR signal were significantly decreased dose-dependently by 1.79-14.32 nmol of 32 kDa dioscorin (r = 0.975) compared to the control. It is suggested that 32 kDa dioscorin, the storage protein of yam tuber, may play a role as antioxidant in tubers and may be beneficial for health when people take it as a food additive or consume yam tubers.

Antioxidants↗
PubMed2005

Biochemical origin of browning during the processing of fresh Yam (Dioscorea spp.) into dried product.

This study was undertaken to follow the kinetics of polyphenoloxidase (PPO), peroxidase (POD), and phenolic compounds during yam blanching at different temperatures and after drying and to identify by high-performance liquid chromatography (HPLC) the main phenolic compounds present in yam products. PPO activity was 50% higher in nonprocessed freeze-dried Florido (Dioscorea alata) than in nonprocessed freeze-dried Deba (Dioscorea rotundata). It decreased progressively during blanching. Forty-five percent of PPO activity remained after 50 min of blanching at 60 or 65 degrees C, whereas the POD activity dropped sharply to less than 20% of the initial activity after 10 min of blanching, whatever the blanching temperature. No anthocyanidins could be detected by HPLC at 520 nm in nonprocessed freeze-dried yam. Flavanols with a maximum absorption wavelength (lambda(max)) at 280 nm and cinnamic acid compounds with 320 nm lambda(max) were detected. Catechin was identified as the major flavanol with concentrations ranging from 0.26 to 0.41 microM g(-)(1) depending on cultivar. One cinnamic compound, ferulic acid, was identified and assessed in both cultivars (0.03-0.04 microM g(-)(1)). Total phenol, flavanol, and cinnamic contents decreased during blanching independently of temperature whereas some unresolved peaks were detected by HPLC in dried product. The latter was probably due to the consumption of coloring precursors and the appearance of polymerized or complex colored products.

Catechol Oxidase↗
PubMed2003

Anti-obesity effect of Dioscorea nipponica Makino with lipase-inhibitory activity in rodents.

In the process of screening for pancreatic lipase inhibitors, which could be used as an anti-obesity measure, the methanol extract of Dioscorea nipponica Makino powder (DP) appeared to have potent inhibitory activity against porcine pancreatic lipase with an IC50 value of 5-10 microg/ml, where the enzyme activity was assayed by using 4-methylumbelliferyl oleate as a substrate. Further purification of active components present in the herb generated dioscin that belongs to the saponin family. Dioscin and its aglycone, diosgenin, both suppressed the time-dependent increase of blood triacylglycerol level when orally injected with corn oil to mice, suggesting their inhibitory potential against fat absorption. Sprague-Dawley rats fed on a high-fat diet containing 5% Dioscorea nipponica Makino and 40% beef tallow gained significantly less body weight and adipose tissue than control animals fed on a high-fat diet alone during an 8-week experimental period (P<0.05).

Adipose Tissue↗
PubMed2001

[Isolation and identification of steroidal saponins from Dioscorea panthaica Prain et Burkill].

AIM: To investigate the chemical constituents of the rhizomes of Dioscorea panthaica Prain et Burkill and look for new active compounds. METHODS: The compounds were isolated with silica gel and HPLC, and their structures were elucidated on the basis of chemical evidences and spectral analysis (IR, ESI-MS, 1HNMR, 13CNMR, DEPT, 1H-1H COSY, HMQC, HMBC, NOESY). RESULTS: Three steroidal saponins were isolated from the rhizomes of Dioscorea panthaica. They were elucidated as 26-O-beta-D-glucopyranosyl-3 beta, 26-diol-23(S)-methoxy-25(R)-delta 5,20(22)-diene-furosta-3-O-[alpha-L-rhamnopyranosyl-(1-->2)- O-alpha-L-rhamnopyranosyl-(1-->4)]-beta-D-glucopyranoside (I), pseudoprotodioscin (II), 26-O-beta-D-glucopyranosyl-3 beta, 26-diol-25 (R)-delta 5,20(22)-diene-furosta-3-O-alpha-L-rhamnopyranosyl- (1-->2)-O-beta-D-glucopyranoside (III). CONCLUSION: Compound I is a new steroidal saponin and was named as dioscoreside C. Compound II and III were obtained from this genus for the first time.

Dioscorea↗
PubMed2003

[FTIR and classification study on trueborn tuber dioscoreae samples].

To identify the origin of tuber dioscoreae, 45 samples were studied by soft independent modeling of class analogy (SIMCA) in this paper. The combination of Fourier transform infrared spectroscopy (FTIR) with mathematic method was used to classify the trueborn and non-trueborn samples. The samples were chosen randomly as modeling group and predicting group. The correctness of classification was 70%. This approach was proved to be a reliable and practicable method for trueborn quality analysis of tuber dioscoreae.

Dioscorea↗
PubMed2004

[Characterisation of Dioscorea bulbifera native starch].

A non conventional source of starch, bulbs of Dioscorea bulbifera, was evaluated. Giving a yield of 28.48 g/100 g on dry weight, chemical composition, physical, physico-chemical and morphological characteristics were assessed, as well as its rheological properties. Chemical analysis showed a amylose content of 29.37%. Micrographies showed that most of the starch granules were of irregular shape, similar to a pyramid with rounded vertices, and a smaller number were elongated with smooth surface. Dioscorea starch showed a gelatinization temperature of 70.8 degrees C and maximum viscosity at 88.6 degrees C of 435 Brabender units (BU). It presented a relatively stable consistency to the cooking process and a low tendency to retrogradation; which suggest the starch possible use in food products that need a fast viscosity and a gel with a stable consistency.

Dioscorea↗
PubMed2004

[Effect of N, P, K on rhizome yield and diosgenin content of Dioscorea zingiberensis].

OBJECTIVE: A field experiment was conducted to investigate the different effects of various applying ratios of nitrogen (N), potassium (K) and phosphate (P) on diosgenin content and Rhizoma yield of Dioscorea zingiberensis. METHOD: Experiment was conducted with both one factor and orthogonal design, and data was analyzed statistically on SPSS 11. 5. RESULTS: Compared with the control groups,the yield of rhizome was significantly increased by N (P < 0.01), K (P < 0.01) , P (P <0.05). The content of diosgenin has no obvious increase (P > 0.05) by individual application of N, P and K, while changed significantly (P < 0.05) by the combination of proper levels of N, P, K. CONCLUSION: The degree of effect on diosgenin content was ranged with N > K > P, while on output of dioscorea rhizome was K > N > P, and the combination of N, K, P2 was superior to others.

Dioscorea↗
PubMed2006

[Determination of nine trace elements in Dioscorea opposita thumb by flame atomic absorption spectrophotometry].

The contents of the potassium, calcium, sodium, magnesium, copper, zinc, iron, manganese, strontium and nickel in Dioscorea opposita thumb were determined. The relative standard deviation(RSD) of the first eight contents is 0.43%, 1.10%, 4.41%, 0.68%, 1.44%, 1.88%, 1.29% and 0.03% respectively, and the percentage recovery is 90.0%-111.0%. The method is convenient and accurate. It can be used to determine the trace elements simultaneousy in Dioscorea opposita thumb.

Dioscorea↗
PubMed2006

[Study on steroidal compounds from Dioscorea zingiberensis].

OBJECTIVE: To study the chemical constituents of Dioscorea zingiberensis. METHOD: Manifold chromatography methods were used to separate the chemical constituents, and the chemical stuctures were determined by spectral analyses. RESULT: 6 compounds were isolated from Dioscorea zingiberensis and identified as deltonin, protodeltonin, zingiberensis newsaponin, dioscin, 3-O-[beta-D-glucopyranosyl(1 --> 4)]-beta-D-glucopyranosyl-diosgenin, diosgenin. CONCLUSION: Deltonin and protodeltonin were isolated from this plant for the first time.

Dioscorea↗
PubMed2004

Simultaneous determination of allantoin, choline and L-arginine in Rhizoma Dioscoreae by capillary electrophoresis.

A rapid, easy and reproducible capillary electrophoresis (CE) method for the simultaneous determination of allantoin, choline and arginine in Rhizoma Dioscoreae was developed first time. Under the optimum condition, the three analytes could be well separated within 5 min in a 70 cm (60 cm effective length) x 75 microm i.d. capillary. The relative standard deviations for both migration time and peak height were less than 3.20%. The linear response range was 5.0-150, 0.9-100 and 1.0-200 microg/ml for arginine, choline and allantoin, respectively. The detection limit of three components was 2.0, 0.4 and 0.5 microg/ml for arginine, choline and allantoin, respectively. Contents of arginine, choline and allantoin in the crude drug of Rhizoma Dioscoreae could be easily determined by the proposed method with satisfactory results.

Allantoin↗