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

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

Making textual research on Bencao and documents, this article inquires to the origin and development of genuine medicinal herbs of Shanyao (Rhizoma Dioscoreae) on the points of change of the growing areas and the development of cultivating and processing techniques and clinical uses. The study indicates that the medicinal use of Dioscorea oposita went through several periods: the period of the use of wild D. oposita before Tang dynasty, the period of the mixed use of wild and cultivating D. oposita from Song to the middle of Qing dynasty, and the period of the main use of cultivating D. oposita after the latter stage of Qing dynasty (18th century). It considers that the growing area of genuine medicinal herbs of Shanyao appeared in Ming dynasty and finally formed "Huaishanyao" on the early of 20th century. The acknowledgement of Huaishanyao as genuine medicinal herbs is related closely to its cultivating and processing techniques and clinical uses. The development of cultivating techniques provided the resource of Shanyao, the invention of processing techniques improved its appearance and quality, and the clinical uses and practices by modern and contemporary famous medical men played an important role to the social approval and development of Huaishanyao.
Dioscorea ; growth & development ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Phytotherapy ; methods

OBJECTIVETo study the production technology of extraction in combination hydrolysis in situ for isolating diosgenin from Dioscorea nipponica by orthogonal design.

METHODThe optimum production conditions were investigated with the recovery of diosgenin as an index by extraction in combination hydrolysis in situ, and were compared with the traditional method.

RESULTExtraction in combination hydrolysis in situ conducted in 1.5 mol x L(-1) sulfuric acid of water containing 75% isopropanol at 100 degrees C for 4.5 h could get higher recovery of diosgenin than traditional methods.

CONCLUSIONThis production technology can get higher recovery of diosgenin, and it is simple, time and money saving.

Dioscorea ; chemistry ; Diosgenin ; isolation & purification ; Hydrolysis ; Pressure ; Sulfuric Acids ; Technology, Pharmaceutical ; methods ; Temperature ; Time Factors

OBJECTIVETo perfect the current standard of Rhizoma Diosoreae and Rhizoma Diosoreae stir-baked with bran by improving quality standards of the two processed pieces.

METHODThe quality standards were established according to 9 batches of processed pieces, separately. The standards contains items of identification, water, total ash, acid-insoluble ash, extractives, heavy metals limit, organochlorine limit, microbial limit and assay.

RESULTThe TLC of the two pieces was characteristed. The contents of acid-insoluble ash in the two pieces were increased, not more than 0.5%, 0.3%, respectively. The content limits of five kinds of heavy metals and harmful elements, two kinds of residual organochlorine pesticides and three microbial limits were increased. There were no more than 2 x 10(-7) of lead, 2 x 10(-7) of cadmium, 1 x 10(-5) of copper, 3 x 10(-7) of arsenic, 1 x 10(-7) of mercury, 1 x 10(-7) of hexachlorocyclohexane (BHC) and 1 x 10(-7) of chlorophenothane (DDT) in the two processed pieces, respectively. There were no more than 2 000 and 600 cfu x mL(-1) in the two pieces, respectively and no more than 30 MPN x 100 g(-1) and fungi can not be tested in the two pieces. The contents of allantoin in the two pieces were no more than 0.15%.

CONCLUSIONThis method is simple and suitable for the quality control of the two processed pieces.

Chemistry, Pharmaceutical ; methods ; standards ; Chromatography, Thin Layer ; Dioscorea ; chemistry ; Quality Control ; Rhizome ; chemistry

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

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