A split-plot experiment was conducted to study the optimum planting density of Nuomi yam in directional groove shallow cultivation. Nuomi yam was the main local cultivar of Dioscorea. The study of this paper may help to give valuable instructions of local production. Three different planting densities and shallow groove diameter were designed in the experiment. The results showed that the fresh weight of aerial part per plant, yield and planting benefit of Nuomi yam tuber were the highest when the planting density was 12 000 plants/hm~2 and the diameter of shallow growth groove was 11.0 cm, while they were the lowest when the planting density was 22 500 plants/hm~2 and the diameter of shallow growth groove was 7.5 cm. Along with the increase of planting density, the fresh weight of aerial part, tuber, fresh yield, benefit and commercial tuber rate of Nuomi yam also decreased. The commercial tuber rate of Nuomi yam of 11.0 cm diameter in shallow growing pot was the highest, while it was the lowest with no shallow growing pot. On the contrary, the content of amylopectin and mucin was the highest when there was no shallow groove, and was the lowest when the diameter of shallow groove was 7.5 cm, although there was no significant difference between the two treatments. Therefore, Nuomi yam with the directional cultivation combination of planting density of 12 000 plants/hm~2 and shallow groove diameter of 11.0 cm showed high yield, good appearance quality, high planting benefit and no obvious adverse effect on internal quality.
Dioscorea

Leaf spot symptoms were frequently observed on yam plants grown in the Yeoju area in Korea during a disease survey in 2008. A total of five isolates of Pseudophloeosporella sp. were obtained from the infected leaves of yam plants. All of the isolates were identified as Pseudophloeosporella dioscoreae based on their morphological and cultural characteristics. A phylogenetic tree derived from the internal transcribed spacer sequences of the fungal isolates showed that the fungus is distinctly separated from species in other related genera. P. dioscoreae isolates caused very tiny spots on leaves of yam plants two weeks after artificial inoculation which were similar to those observed in the field. This is the first report that Pseudophloeosporella dioscoreae causes leaf spot in yams in Korea.
Cultural Characteristics ; Dioscorea ; Fungi ; Korea

During 2007 survey of post-harvest diseases of yam performed in May and June, severe tuber loss caused by blue mold was observed in Iksan, Cheonbuk Province. Two species of Penicillium were isolated from the infected tubers. Based on beta-tubulin gene sequence analysis, and cultural and morphological characteristics, the isolates were identified as Penicillium sclerotigenum and P. polonicum. P. sclerotigenum, which is a novel to Korea, is presently described and illustrated.
Dioscorea ; Fungi ; Korea ; Penicillium ; Sequence Analysis ; Tubulin

Animals ; Diabetic Nephropathies ; drug therapy ; Dioscorea ; chemistry ; Polysaccharides ; pharmacology ; Rats

To study the chemical constituents of Dioscorea zingiberensis Wright, the EtOH extract of fresh rhizomes of D. zingiberensis was concentrated and partitioned further to produce petroleum ether-, ethylacetate-, n-butanol- and water-soluble fractions. The water-soluble fraction was subjected to column chromatography on macro resin AB-8, and the final products were obtained by repeated reversed-phase ODS and MCI gel CHP 20P column chromatography. Structures of compounds were elucidated by 1H NMR, 13C NMR, 135DEPT, HMQC, HMBC and TOCSY spectroscopic analyses. A new steroidal saponin was isolated, which was identified as (25R)-26-O-(beta-D-glucopyranosyl)-furost-5-en-3 beta, 16, 20, 26-tetraol-22-seco-3-O-beta-D-glucopyranosyl-(1--> 3)-beta-D-glucopyranosyl-(1--> 4)-[alpha-L-rhamnopyranosyl-(1-->2)]-beta-D-glucopyranoside. The compound is a novel skeletally steroidal saponin, named as zingiberenin F (1). It was reported for the first time from D. zingiberensis Wright.
Dioscorea ; chemistry ; Molecular Structure ; Plants, Medicinal ; chemistry ; Rhizome ; chemistry ; Saponins ; chemistry ; isolation & purification

Diosgenin is an important raw material in steroid hormone and widely used in pharmaceutical industry. The traditional method for diosgenin production is acidolysis, which causes serious pollution. In order to obtain a cleaner and more efficient approach of diosgenin production, a strain of Gibberella intermedia WX12 (the sexual stage of Fusarium proliferatum) was screened from the strains deposited in our laboratory. This strain converted saponins in Dioscorea zingiberensis C.H. Wright (DZW) into diosgenin. The conversion medium was optimized by statistical experimental design. The optimized conversion medium was as follows (g/L): glucose 20.6, yeast extract 5.0, NaCl 1, K2PO4 3, ZnSO4 x 7H2O 1.5 and saponins 3. Under the optimal conditions, the yield of diosgenin achieved to (31 +/- 0.3) mg/g DZW, which was 3 times higher than that of the original medium.
Biotransformation ; Culture Media ; Dioscorea ; chemistry ; Diosgenin ; metabolism ; Gibberella ; growth & development ; metabolism ; Saponins ; metabolism

Based on the results of the morphologic studies on genus Dioscorea, the paper summarized the entire chemical constituent that isolated from this genus and analyzed it with the methods of chemotaxonomy. The rules of the chemical constituent and pharmacodynamic effects were analyzed. Seventeen species which belong to Sect. Stenophora Uline of Dioscorea contain steroidal sapogenin. Other species with different main components such as polysaccharide and tannin have have different effects. This chemotaxonomic view point will conduce to establish a phylogeny of the genus Dioscorea.
Animals ; China ; Dioscorea ; chemistry ; classification ; genetics ; growth & development ; Humans ; Phylogeny ; Plant Extracts ; chemistry ; pharmacology

To establish a HPLC-ELSD fingerprint for total steroid saponins in herbs of Dioscorea zingiberensis. Welchrom C,8 (4. 6 mm x 250 mm,5 microm) chromatographic column was adopted and eluted with the mobile phase of acetonitrile (A)-water (B) at the flow rate of 1.0 mL min-1. The column temperature was room temperature. The ELSD conditions were as follows: the temperature of drift tube was 90.0 degreeC, the flow rate of carrier gas (N2) was 2. 8 L min-1, and the injection volume was 10 microL. After the detection of 10 batches of samples,the common mode of HPLC-ELSD fingerprint for total steroid saponins in herbs of D. zingiberensis was established for the first time,and 25 common peaks were determined. Among them, 10 peaks were identified by comparing with reference substances. The similarities of 10 batches of herbs were evaluated in the common mode. All of them were higher than 0. 80. This method is so accurate, reliable and highly repeatable that it can provide scientific basis for evaluating and controlling the quality of total steroid saponins in herbs of D. zingiberensis.
Chromatography, High Pressure Liquid ; methods ; Dioscorea ; chemistry ; classification ; cytology ; Saponins ; analysis

AIMTo investigate the water-soluble steroidal saponins in total saponin from Dioscorea nipponica Makino and look for new active compounds.

METHODSThe 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.

RESULTSThe 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).

CONCLUSIONCompound II is a new steroidal saponin and firstly isolated from Dioscorea nipponica Makino. It was named as dioscin Dc.

Dioscorea ; chemistry ; Molecular Conformation ; Molecular Structure ; Plants, Medicinal ; chemistry ; Rhizome ; chemistry ; Saponins ; chemistry ; isolation & purification

OBJECTIVETo study the chemical constituents of Dioscorea opposita.

METHODThe chemical constituents were isolated and purified by silica gel column chromatography, and the structures were elucidated by their spectroscopic data and physico-chemical properties.

RESULTTwelve compounds were obtained and identified as palmitic acid (1), beta-sitosterol (2), oleic acid (3), beta-sitosterol acetate (4), 5-(hydroxymethyl)furfural (5), nonanedioic acid (6), beta-daucosterol (7), cyclo-(Phe-Tyr) (8), cyclo-(Tyr-Tyr) (9), 6-methyl citrate (10), 1, 5-dimethyl citrate (11), trimethyl citrate (12).

CONCLUSIONCompounds 3-12 were isolated from this plant for the first time and cyclodipeptides were firstly isolated from the Dioscoreae family; Compound 9 was a new natural product.

Chromatography, Gel ; Dioscorea ; chemistry ; Drugs, Chinese Herbal ; chemistry ; Magnetic Resonance Spectroscopy ; Mass Spectrometry