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PubMed1997

[A comparative study on chemical constituents in different processed products of Dioscorea opposita].

The quantitative comparisons of Water-soluble extract, alcohol-soluble extract and allantoin in crude and three processed products of Dioscorea opposita is carried out by the method recorded in Pharmacopoeia and TLCS respectively. As a result, the changes of water-soluble extract and alcohol-soluble extract during the four samples are similar. It is the hightest in the processed product stir-fried with soil and lowest in the crude. But for allantoin, it is the highest in the processed product stir-fried with wheat bran and lowest in that stir-fried with no material. It is suggested that the contents between water-soluble extract, alcohol-soluble extract and allantoin are not interrelated. It shall be considered to increase the content of allantoin as a quality control index to control the quality of the processed products.

Allantoin↗
PubMed2002

[Study on the quality of Rhizome of Dioscorea persimilis].

OBJECTIVE: To evaluate the quality of Rhizome of D. persimilis Prain et Burk. METHODS: Determined the contents of 6 qualitative indexes in samples of Rhizome of D. persimilis Prain et Burk that were cultivated in Yongning, Bobai, Beiliu, Guiping and Rongxian of Guangxi and in sample of Rhizome of Dioscorea opposita Thunb, that was cultivated in Wenxian, Henan province. RESULTS: The contents of water in them (%): 15.39, 18.52, 15.41, 13.96, 15.48, 15.74; the contents of protein in them (%): 7.06, 8.45, 9.20, 9.67, 8.63, 9.79; the contents of starch in them (%): 84.51, 86.51, 82.72, 83.65, 84.19, 79.13; the contents of water extracts in them (%): 6.19, 6.98, 8.95, 7.41, 6.70, 9.40; 90% EtOH extracts in them (%): 2.00, 2.04, 2.68, 2.20, 2.11, 3.53; the contents of 18 kinds of amino acids in them (%): 5.23, 6.31, 6.22, 6.78, 6.59, 6.83. CONCLUSION: The quality of Rhizome of D. persimilis Prain et Burk cultivated in Guiping or Beiliu is beter than that of Rhizome of D. persimilis Prain et Burk cultivated in Yongning. The quality of Rhizome of D. persimilis Prain et Burk cultivated in Rongxian or Bobai are between those of Rhizome of D. persimilis Prain et Burk cultivated in Guiping or Beiliu and Rhizome of D. persimilis Prain et Burk cultivated in Yonging. The qualities of Rhizome of D. persimilis Prain et Burk cultivated in Guiping or Beiliu are similar to that of Yam.

Amino Acids↗
PubMed2003

Two new non-steroidal constituents from Dioscorea futschauensis R. Kunth.

Dioscorone A (1) and a new isocoumarin derivative (2) were isolated from the rhizome of Dioscorea futschauensis R. Kunth. The structures of 1 and 2 were elucidated on the basis of detailed analysis of NMR spectra. Their anti-fungal activity against Pyricularia oryzae and cytotoxic activity on K562 and HCT-15 cell lines were evaluated in vitro.

Antifungal Agents↗
PubMed2002

[Comparative study on anti-hypercholesterolemia activity of diosgenin and total saponin of Dioscorea panthaica].

OBJECTIVE: To compare the anti-hypercholesterolemic and cholesterol absorption inhibitory activities between total saponin of Dioscorea panthaica (TSDP) and diosgenin (Dio). METHOD: TSDP and Dio were given ig or i.p. to mice or rats treated with cholesterol feed to evaluate their preventive and therapeutic effect on hypercholesterolemia. TSDP or Dio and cholesterol were mixed with pig bile to form the micelle, then the freeing cholesterol was detected to evaluate inhibitory effect of the both compounds on cholesterol absorption. RESULT: Dio (80 and 160 mg.kg-1) showed significantly therapeutic and preventive effect on hypercholesterolemia in mice, while TSDP showed a certain preventive activity only at a big dose (400 mg.kg-1). The intraperitoneal injection of Dio (20 and 40 mg.kg-1) to mice suffered from hypercholesterolemia was effective, but TSDP showed no effective. The serum total cholesterol level was decreased when rats were pre-treated with TSDP (200 and 400 mg.kg-1, ig) and Dio (200 and 100 mg.kg-1, ig). However, the hypercholesterolemia-preventing activity of Dio was stronger than that of TSDP. In addition, inhibitory effect of Dio on cholesterol micelle formation was still stronger than that of TSDP. CONCLUSION: The preventive and therapeutic activity of Dio against hypercholesterolemia indused by cholesterol in mice or rats is stronger than that of TSDP. The anti-hypercholesterolemia mechanism of Dio is probably related with its cholesterol absorption inhibitory activity.

Animals↗
PubMedDate not supplied

Genetic stability assessment of plants regenerated from cryopreserved embryogenic tissues of Dioscorea bulbifera l. Using RAPD, biochemical and morphological analysis.

Embryogenic tissues of Dioscorea bulbifera were cryopreserved using the encapsulation-dehydration technique. Genetic stability of plants regenerated from cryopreserved embryogenic tissues was assessed using molecular, biochemical and morphological analysis. The random amplified polymorphic DNA (RAPD) analysis of 60 cryopreserved-derived and 20 in vitro grown (control) plantlets showed that 10 primers produced 62 clear reproducible DNA fragment profiles. The amplification products were monomorphic for all the plantlets except one. A total of 4960 DNA fragments were obtained from this study showing no variation in RAPD profiles. The diosgenin content of cryopreserved-derived plants, analyzed using HPLC, was similar to that of control plants. Morphology and the ability to form microtuber were also found to be unaltered in cryopreserved embryo-derived plantlets. Thus, the D. bulbifera plants regenerated from cryopreserved embryogenic tissues were genetically stable at the molecular, biochemical and morphological levels.

Chromatography, High Pressure Liquid↗
PubMed2004

Steroidal saponins from Dioscorea panthaica and their cytotoxic activity.

A new steroidal saponin, dioscoreside E (1), and a known compound, protodioscin (2), were isolated from an ethanol extract of the rhizomes of Dioscorea panthaica. The structure of 1 was established as 3-O-[bis-alpha-L-rhamnopyranosyl-(1 --> 2 and 1 --> 4)-beta-D-glucopyranosyl]-26-O-beta-D-glucopyranosyl-20(R)-methoxy-25(R)-furosta-5,22(23)-diene-3beta,26-diol, on the basis of spectral and chemical evidence. Compounds 1 and 2 showed cytotoxic activity against a panel of tumor cell lines.

Animals↗
PubMed2003

[Studies on liver-toxicity in rhigoma of Dioscorea bulbifera].

OBJECTIVE: To explore the liver-toxic fraction in Rhigoma of Dioscorea bulbifera. METHOD: The rats were randomized into four groups: control group (20% PVP-water), T001(10% total methanol extraction), F002(5% chloroform fraction) and F003(5% methanol fraction). Direct bilirubin (DBil) and Glutamic-pyruvic transaminase (GPT) were examined, and liver index was measured. The histological and morphological observations were performed with optical and electrical microscope. RESULT: T001 and F002 showed significant liver toxicity. CONCLUSION: The chloroform fraction was the liver-toxic fraction of D. bulbifera.

Alanine Transaminase↗
PubMed2004

[Studies on the dynamic trends of diosgenin content in vegetative organs of Dioscorea zingiberensis].

Diosgenin was determined by HPLC to study dynamic trend of diosgenin content in vegetative organs especially the rhizome, and the differences of diosgenin content between strains and between male and female rhizomes of Dioscorea zingiberensis C. H. Wright. The results are as follows: Diosgenin content of biennial seedling rhizome is higher than that of annual seedling rhizome; Diosgenin content of biennial rhizome derived from vegetative propagation is higher than that of annual rhizome derived from vegetative propagation; In piebald leaf strain is higher than in green leaf strain; In male is higher than in female. Diosgenin was not detected in twining stem nor in leaf. Diosgenin content of annual rhizome from vegetative propagation increased slowly at early stage, and it increased comparatively quickly at later stage; Diosgenin content of biennial rhizome at the stage of blossom is the highest, and it is the lowest at the later stage of bloom, afterwards it increases gradually. So cultivated variety of higher output and higher fastness should be chosen from the piebald leaf strain. The right time to collect rhizome should be at the stage of twining stem withering.

Chromatography, High Pressure Liquid↗
PubMed2004

[Studies on plantlet regeneration from the mature leaves of Dioscorea zingiberensis].

OBJECTIVE: To establish a protocol of rapid clonal propagation of Dioscorea zingiberensis using mature leaves as explants. METHOD: Out the optimal hormone combinations for callus induction, adventitious bud initiation, adventitious bud multiplication and rooting were found out by using MS medium with the macroelements at half strength as basal medium and studying the effects of BA, NAA and IBA on the processes. RESULT AND CONCLUSION: More than 80% of leaf explants formed callus when they were cultured on the media containing 1.0 - 5.0 mg x L(-1) BA and 1.0 - 2.0 mg x L(-1) NAA for 60 days; more than 60% of calli initiated adventitious buds within 50 days after they were transferred to the media containing 2.0 - 5.0 mg x L(-1) BA and 0.2 - 0.5 mg L(-1) NAA; all the adventitious buds rooted well after they were planted on the medium with 2.0 mg x L(-1) IBA for 20 days; the regenerated plantlets grew vigorously after they were transplanted and the survival rate was up to 80%.

Culture Media↗
PubMedDate not supplied

[Adaptogenic effects of furostanol glycosides of Dioscorea deltoidea wall on oxidative processes in tomato plants in biotic stress].

The effect of furostanol glycosides of cell culture of Dioscorea deltoidea Wall on oxidative processes in tomato plants subjected to invasion with the gall nematode Meloidogyne incognita Kofoid et White was studied. We showed that furostanol glycosides induce a nonspecific defensive response in plants. Exposure of cell membranes to furostanol glycosides cause rearrangements in fatty acids resulting in the formation of conjugated dienes, which makes molecules thermodynamically more stable under stress conditions. The study of changes in the activity of peroxidases of intact plants and plants affected with the nematode, which were treated with furostanol glycosides, showed that the protective effect of the guaiacol-dependent peroxidase is more long-term than the effect of the benzidine-dependent peroxidase.

Adaptation, Physiological↗
PubMed2005

[Genetic diversity of yam (Dioscorea opposita Thunb) detected by ISSR markers].

Genetic diversity of 28 cultivars of yam (Dioscorea opposita Thunb) was assessed by means of Inter-simple sequence repeat (ISSR) markers. The results showed that seven proper primers, with rich polymorphism, could be selected from a total of forty four ISSR ones; distinct differences appeared among 28 cultivars amplified bands, and the rate of polymorphic bands was 83.01%; Shannon's Information index was 0.3191; a Jaccard's genetic similarity matrix and a dendrogram for these cultivars were formed, in which they could be divided into four groups: Group 1 was composed of D. opposita. cv. Ribenbai, D. opposita. cv. Huashanyao and D. opposita. cv. Ribenyuan; Group2 contained D. opposita. cv. Xiaoye; Group 3 contained D. opposita. cv. No.1 Songye; other 23 cultivars were put into Group4. PCA(Principal component analysis) was employed to evaluate the resolving power of the markers to differentiate among them. This laid the foundation of the identification of yam cultivars and the efficient use of its germplasm resources.

DNA, Plant↗
PubMed2005

[Study on model of heat and mass transfer in Dioscorea opposita with microwave drying technique].

A new mathematical model, aimed at investigating the behaviors of microwave drying of traditional chinese medicine was established. It based on mass-energy consersvation law. Dioscorea opposita Thunb. was used as sample and its drying efficiency have been developed at different levels of microwave power and sample thickness. The results shown that the levels of them have a strong influence on drying process. The experimental values were approximately in accord with the calculated values by mathematical model. It explained successfully the behaviors of microwave drying of Diosorea opposita Thunb. slices.

Algorithms↗
PubMed2005

[Progress and prospect of botancial research in Dioscorea zingiberensis].

This paper is a summary of the progress of botanical research in Dioscorea zingiberensis. It contains biological characteristic, genetic diversity, growth circumstance, breeding, cultivating, tissue and cell culture of D. zingiberensis. According to the fact of market demanding and resources protection, the writers propose that some work, including establishing gene bank, resources appraise, employing advanced technology to utlize the resources and making the cultivated standard, should be taken into consideration.

Cell Culture Techniques↗
PubMed2006

[Effect of potassium level on output and diosgenin content of Dioscorea zingiberensisg].

OBJECTIVE: To study the effect of potassium level on physiological characteristics and diosgenin content of Dioscorea zingiberensisg and provide experimental basis for proper use of potassium fertilizer. METHODS: Field experiment including four potassium levels was carried out. The physiological characteristics of leaves were determined at different growth stages and the diosgenin content in bulk root was assayed after harvest. RESULTS: Within the arrange of 0-180 kg K2SO4/hm2, the content of chlorophyll and amino acid, Fv/Fo, Fv/Fm, and phiPs II were increased with the increase in potassium level. Meanwhile, the ability to defense the damage caused by active oxygen was obviously enhanced. Further increase in potassium level resulted in the decrease in efficiency of potassium fertilizer. CONCLUSION: It indicats that higher yield and diosgenin content can be obtained when the potassium level is 180 kg K2/hm2.

Amino Acids↗
PubMed2000

Effects of selected process parameters in extrusion of yam flour (Dioscorea rotundata) on physicochemical properties of the extrudates.

Raw yam (Dioscorea rotundata) flour was cooked and extruded in a Brabender single-screw laboratory scale extruder. Response surface methodology using an incomplete factorial design was applied with various combinations of barrel temperature [100, 125, 150 degrees C], feed moisture content [18, 22, 26%] and screw speed [100, 150, 200 rpm]. Initial viscosity at 30 degrees C, water solubility index, expansion and hardness were determined. The highest values of initial viscosity were at the highest barrel temperatures and the highest moisture contents. At high feed moisture content and high barrel temperatures the yam extrudate flour showed the greatest values of water solubility index. The physical properties of the extruded product showed that at high temperature the lower the moisture content the greater the expansion index. Hardness was influenced directly by moisture content and inversely by extrusion temperature. The extrusion of yam flour led to the production of snacks and pre-gelatinized flours of diverse properties. Also extruded yam flour can be successfully used in the preparation of 'futu' (pre-cooked compact dough), a yam-based food, popular in Western Africa.

Chemical Phenomena↗
PubMed1995

Isolation and characterisation of cDNA clones representing the genes encoding the major tuber storage protein (dioscorin) of yam (Dioscorea cayenensis Lam.).

cDNA clones encoding dioscorins, the major tuber storage proteins (M(r) 32,000) of yam (Dioscorea cayenesis) have been isolated. Two classes of clone (A and B, based on hybrid release translation product sizes and nucleotide sequence differences) which are 84.1% similar in their protein coding regions, were identified. The protein encoded by the open reading frame of the class A cDNA insert is of M(r) 30,015. The difference in observed and calculated molecular mass might be attributed to glycosylation. Nucleotide sequencing and in vitro transcription/translation suggest that the class A dioscorin proteins are synthesised with signal peptides of 18 amino acid residues which are cleaved from the mature peptide. The class A and class B proteins are 69.6% similar with respect to each other, but show no sequence identity with other plant proteins or with the major tuber storage proteins of potato (patatin) or sweet potato (sporamin). Storage protein gene expression was restricted to developing tubers and was not induced by growth conditions known to induce expression of tuber storage protein genes in other plant species. The codon usage of the dioscorin genes suggests that the Dioscoreaceae are more closely related to dicotyledonous than to monocotyledonous plants.

Amino Acid Sequence↗
PubMed1994

Nutritional assessment of yam (Dioscorea alata) tubers.

The nutrient and antinutrient components of tubers from seven cultivars of Dioscorea alata were determined. The average crude protein content of D. alata tubers was 7.4%. Starch (75.6-84.3%) was the predominant fraction of the tuber dry matter. Significant differences in crude protein and starch contents were observed among cultivars. Vitamin C content of the yam tubers ranged from 13.0 to 24.7 mg/100 g fresh weight. The results showed yams to be reasonably good sources of minerals. Phytic acid contents of the yams were low, with values ranging from 58.6 to 198.0 mg/100 g dry matter. Total oxalate levels in yam tubers were found to be in the range of 486-781 mg/100 g dry matter, but may not constitute a nutritional concern since 50-75% of the oxalates were in the water-soluble form. The overall results are suggestive of the nutritional superiority of yams compared to other tropical root crops.

Minerals↗