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At least 271 records · Page 15Linked to original sources
PubMed2003

Tuber storage proteins.

A wide range of plants are grown for their edible tubers, but five species together account for almost 90 % of the total world production. These are potato (Solanum tuberosum), cassava (Manihot esculenta), sweet potato (Ipomoea batatus), yams (Dioscorea spp.) and taro (Colocasia, Cyrtosperma and Xanthosoma spp.). All of these, except cassava, contain groups of storage proteins, but these differ in the biological properties and evolutionary relationships. Thus, patatin from potato exhibits activity as an acylhydrolase and esterase, sporamin from sweet potato is an inhibitor of trypsin, and dioscorin from yam is a carbonic anhydrase. Both sporamin and dioscorin also exhibit antioxidant and radical scavenging activity. Taro differs from the other three crops in that it contains two major types of storage protein: a trypsin inhibitor related to sporamin and a mannose-binding lectin. These characteristics indicate that tuber storage proteins have evolved independently in different species, which contrasts with the highly conserved families of storage proteins present in seeds. Furthermore, all exhibit biological activities which could contribute to resistance to pests, pathogens or abiotic stresses, indicating that they may have dual roles in the tubers.

Amino Acid Sequence↗
PubMed2006

Farmers' use of wild relative and sexual reproduction in a vegetatively propagated crop. The case of yam in Benin.

The impact of traditional farmers' management on genetic diversity of vegetatively propagated crops is poorly documented. In this study, we analysed the impact of ennoblement of spontaneous yams, an original traditional farmers' practice, on the genetic diversity of yam (Dioscorea sp.) in Benin. We used 11 microsatellite markers on yam tubers from a small village in northern Benin and demonstrated that wild x cultivated hybrids are spontaneously formed. Many of the spontaneous yams collected by farmers from surrounding savannah areas for ennoblement were shown to be of wild and hybrid genotypes. Moreover, we demonstrated that some yam varieties have a wild or hybrid signature. Lastly, we performed a broader ranging genetic analysis on yam material from throughout Benin and showed that this practice is used in different ecological and ethno-linguistic regions. Through this practice, farmers create new varieties with new genetic combinations via sexual reproduction of wild and cultivated yams. This system, whereby a sexual cycle and asexual propagation are mixed, ensures potential large-scale cultivation of the best genotypes while preserving the potential for future adaptation.

Benin↗
PubMed2003

Plant chitinase as a possible biocontrol agent for use instead of chemical fungicides.

We investigated whether a plant chitinase can be used as a biocontrol agent instead of chemical fungicides by spraying chitinase E (family 19; class IV) from a yam (Dioscorea opposita Thunb) alone or together with beta-1,3-glucanase directly onto the surface of a powdery mildew infecting strawberry berries and leaves. Results were observed by eye and with a scanning electron microscope. The powdery mildew infecting the strawberries was degraded, mainly by the chitinase, and the disease did not appear again for more than 2 weeks. These results indicated that this kind of plant chitinase might be safe and biodegradable biocontrol agent for use instead of conventional fungicides.

Chitinases↗
PubMed2004

Molecular cloning of a genomic DNA encoding yam class IV chitinase.

Genomic DNA for a class IV chitinase was cloned from yam (Dioscorea opposita Thunb) leaves and sequenced. The deduced amino acid sequence shows 50 to 59% identity to class IV chitinases from other plants. The yam chitinase, however, has an additional sequence of 8 amino acids (a C-terminal extension) following the cysteine that was reported as the last amino acid for other class IV chitinases; this extension is perhaps involved in subcellular localization. A homology model based on the structure of a class II chitinase from barley was used as an aid to interpreting the available data. The analysis suggests that the class IV enzyme recognizes an even shorter segment of the substrate than class I or II enzymes. This observation might help to explain why class IV enzymes are better suited to attack against pathogen cell walls.

Amino Acid Sequence↗
PubMed2004

Intracellular localization of a class IV chitinase from yam.

Genomic DNA encoding a class IV chitinase was cloned from yam (Dioscorea opposita Thunb) leaves in previous research (Biosci. Biotechnol. Biochem., 68, 1508-1517 (2004)). But this chitinase had an additional sequence composed of eight amino acids (a C-terminal extension) at the C-terminal, compared with class IV chitianses from other plants. In order to clarify the role of this C-terminal extension in cellular localization, plants and suspension-cultured cells of Nicotiana tabacum were transformed with either the cloned yam class IV chitinase gene carrying the C-terminal extension or its truncated gene by the Agrobacterium-mediated method, and then their localization was investigated. The results suggest that the C-terminal extension of yam class IV chitinase plays a role as a targeting signal for plant vacuoles. This is the first report presenting the existence of vacuolar type class IV chitinase.

Chitinases↗
PubMed2002

[Kooroo color: 90-day dietary toxicity study in F344 rats].

A subchronic toxicity study on kooroo color was conducted using F344 rats of both genders. Kooroo color is an extract of yam root, Dioscorea matudai Hayata, of which the major components are known to be flavonoid pigments. Use of kooroo as a food color is permitted by the Food Sanitation Law in Japan, but the chronic toxicity has not been evaluated in the literature. Rats were fed the product of kooroo color (PKC) at doses of 0.5%, 1.50%, and 5.0% in basal powder diet, while control groups received PKC-free basal diet, for ninety days. A vehicle control given propylene glycol (PG) alone, at the same dosage that the 5.0% group received, was included, because PKC used in this study contained ca. 80 percent PG, used as an extractant during the manufacturing processes. Daily observation of general behavior, and weekly measurement of body weight as well as food consumption were performed. Hematological, serum biochemical and anatomopathological examinations were conducted at the end of administration. No abnormalities ascribable to the treatment with PKC or PG were noted in any examination in this study. Hence, dietary intake of 5.0% of PKC, i.e., 2,993 mg/kg/day for males, and 3,376 mg/kg/day for females, as a mean daily intake for 90 days, had no observable adverse effect in F344 rats. Therefore, kooroo color has no significant general toxicity, and its toxicity, if any, is of a very low order.

Animals↗
PubMedDate not supplied

The cytotoxicity of methyl protoneodioscin (NSC-698791) against human cancer cell lines in vitro.

Methyl protoneodioscin (NSC-698791) is a furostanol saponin isolated from the rhizome of Dioscorea collettii var. hypoglauca (Dioscoreaceae), a Chinese herbal remedy for the treatment of cervical carcinoma, carcinoma of the urinary bladder and renal tumor for centuries. In order to systematically evaluate its potential anticancer activity, methyl protoneodioscin cytotoxicity was tested in vitro against 60 human cancer cell lines in the NCI's (National Cancer Institute, USA) anticancer drug screen. As a result, methyl protoneodioscin was cytotoxic against all the test cell lines from leukemia and solid tumors in the NCI's human cancer panel, especially selectively against one non-small cell lung cancer (NSCLC) line (A549/ATCC), one colon cancer line (HCT-116), two central nenous system (CNS) cancer lines (SF-539 and SNB-75), one melanoma line (M14), one renal cancer line (CAKI-1), one prostate cancer (DU-145) and two breast cancer lines (HS 578T and MDA-MB-435) with GI50 < or = 2.0 microM. The selectivity between these nine most sensitive lines and the least sensitive line (TK-10) was from 22- to 30- fold. In the same cancer subpanel, a selectivity at GI50 level of more than 15-fold was observed between A549/ATCC and EKVX (NSCLC), between CAKI-1 and TK-10, A498 (renal cancer), respectively. In general the CNS cancer was the most sensitive subpanel, while renal cancer was the least sensitive subpanel. Based on an analysis of COMPARE computer program with methyl protoneodioscin as a seed compound, no compounds in the NCIs anticancer drug screen database have similar cytotoxicity patterns (mean graphs) to that of methyl protoneodioscin, indicating a potential novel mechanism of anticancer action involved.

Antineoplastic Agents, Phytogenic↗
PubMed2002

Effects of "Chinese yam" on hepato-nephrotoxicity of acetaminophen in rats.

AIM: To study the effect of yam in Taiwan, which is a commonly used Chinese medicine, on hepato-nephro-toxicity in rats. METHODS: Crude water extract of yam (Dioscorea alata L), was used to treat rats with an acute toxicity induced by acetaminophen (APAP) challenge. RESULTS: The pharmacological and biochemical studies showed the extract of yam had the effect of kidney secureness and liver fortification (P < 0.01). The pathologic sections showed good improvements in renal tubular degranulation changes, necrosis and disintegration. The extract of yam also possessed a good protection against the inflammation of central vein and necrosis of liver tissue. CONCLUSION: The liver and kidneys are originated from the same source. Pathologically, deficiency of the life essence in the kidney may lead to the blood deficiency in the liver. The results showed that the yam could prevent the damages of the liver and kidneys, thus preserving their functions. This could b e the reason why the yam was commonly used in traditional Chinese medicine, as seen in Liuwei Dihuang Wan be used in the case of deficiency of liver-yin and kidney-yin.

Acetaminophen↗
PubMed2002

[Intestinal bacteria metabolism of TSDP and characterization of metabolites in rats].

OBJECTIVE: To study the rat intestinal bacteria metabolism of total saponins of Dioscorea pathaica (TSDP) in vitro, and characterize the metabolites in serum and urine of rats after oral administration of TSDP 900 mg.kg-1. METHOD: TSDP metabolites were detected with thin-layer chromatography (TLC) and combination of electrospray ionization mass spectrometry (ESI-MS) and sequential tandem mass spectrometry (MSn). RESULT: In vitro, TSDP was decomposed easily by rat intestinal bacteria, and metabolites DP-1, DP-2, DP-4, DP-5 and diosgenin (Dio) were observed with prolongation of incubation time by ESI-MS2. In vivo, in the full-scan positive mass spectrum of the rat urine sample, the ion peak at m/z 415 (M-H) and its characteristic fragmentations at m/z 397 and m/z 271 in the MS/MS spectrum were identified with that of metabolite Dio, therefore metabolite Dio was deduced to exist in the rat urine, and metablite Dio was allso detected in the rat serum sample. CONCLUSION: TSDP is decomposed easily by rat intestinal bacteria and metabolite diosgenin is absorbed into blood after oral administration of TSDP.

Animals↗
PubMed2003

[Study on the production condition of extraction in combination hydrolysis in situ for isolating diosgenin].

OBJECTIVE: To study the production technology of extraction in combination hydrolysis in situ for isolating diosgenin from Dioscorea nipponica by orthogonal design. METHOD: The 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. RESULT: Extraction 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. CONCLUSION: This production technology can get higher recovery of diosgenin, and it is simple, time and money saving.

Dioscorea↗
PubMed2004

[Nutritional characterization of carbohydrates and proximal composition of cooked tropical roots and tubers produced in Costa Rica].

Tropical roots and tubers (TRT) are important staple foods in the tropics. TRT are produced by small farmers and have received only limited attention. The objective of this paper was to evaluate nutritionally important carbohydrate fractions and proximal composition of cooked cassava (Manihot esculenta), cocoyam- or tannia- (Xantosoma sp) and yam (Dioscorea alata) grown in Costa Rica. Twenty boiled samples of each TRT were analyzed for proximal composition, following AOAC protocols. Carbohydrate fractions (dietary fiber, available and resistant starch) and alpha-amylolysis rate were assessed by enzymatic methods. All TRT analyzed consisted mainly of water and carbohydrates, representing moderate dietary fiber and energy sources. They show a low protein level and contain no fat. Moisture, protein, ashes and dietary fiber contents vary significantly (p<0.01) among the three species. In terms of their proximal composition, these locally grown TRT differ from TRTs cultivated in the South Pacific area, but appear similar to other Latin American varieties. In all samples most of the dietary fiber (84-88%) is insoluble; available starch ranges between 74 and 84% of the dry matter, whereas resistant starch content varied between 0.7 and 1.7%. Amylolysis rate was similar for cassava and cocoyam, whereas a significantly slower digestion (p<0.01) was recorded for yam. Compared to values reported in the literature for other starchy foods and to gelatinized potato starch, used as reference sample, the studied TRT showed intermediate amylolysis rates. It is concluded that consumption of these TRT may be promoted in Costa Rica and other countries with a similar nutritional situation.

Consumer Behavior↗
PubMedDate not supplied

Cryopreservation of yams using vitrification modified by including droplet method: effects of cold acclimation and sucrose.

Cryopreservation of yams (Dioscorea spp.) is important for the preservation of valuable genotypes for food, medicine and breeding purposes. This study on four species of yams was conducted to evaluate the influence of cold acclimation in an alternating 5 degree C and 28 degree C, 12 h thermo-photo-period and of two sucrose concentrations in the preculture medium using a modified droplet method. Acclimation of a 3-week period provided the best preconditioning treatment averaged over four genotypes. Effect of sucrose concentration in the preculture medium depended on the genotype (significant genotype x sucrose interaction; P = 0.036). High survival (67 to 70%) with 30% to 50% shoot recovery was obtained for D. bulbifera, D. polystachya and D. cayenensis, compared to 20 percent survival without shoot recovery for D. alata.

Acclimatization↗
PubMed2006

[Manaca, sweet potato and yam: possible substitutes of wheat in foods for two ethnic population in Venezuelan Amazon].

In this study, flours from manaca or acai (Euterpe oleracea Mart), sweet potato (Ipomea batatas), and yam (Dioscorea spp.), species grown in the Venezuelan Amazon, were obtained. The proximal composition, water activity (a(w)), Fe, Ca, Zn, Mg, Cu, Na and K content were determined for the flours of manaca, sweet potato and yam. These flours were used as ingredients of products for the inhabitants of the indigenous populations of the Venezuelan Amazon (Piaroa and Hiwi). Two types of products that traditionally contain wheat flour in their formulation (ingredient they know by transculturation) were formulated; an attempt to substitute it totally or partially by the manaca, sweet potato and/or yam flours was made. For the selection of the products to be formulated, the preferences and eating habits of the indigenous communities and ease and simplicity of the preparations to be developed, were considered. The two products formulated were cookies and "small cakes". To decide on the formulation(s) of the final product(s), sensorial evaluations were made in the laboratory and in the indigenous communities Piaroa and Hiwi. High fat content (16%), dietetic fiber (59.7%) and iron (25 mg / 100 g) in manaca or acai flour were remarkable. Two types of cookies and two of "small cakes" were equally accepted by the indigenous communities. Cookies supply a high iron amount (about 24%). The feasibility of substituting the wheat flour by manaca, sweet potato and yam flour in products accepted by two ethnic populations of the Venezuelan Amazon was demonstrated.

Arecaceae↗
PubMed2000

The ameliorating effects of the cognitive-enhancing Chinese herbs on scopolamine-induced amnesia in rats.

Ameliorating effects were investigated of the cognitive-enhancing Chinese herbs administered orally for 1 week-Panax ginseng (PG), Panax notoginseng (PNG), Dioscorea opposita (DO), Gastrodia elata (GE), Salvia miltiorrhiza (SM), Acorus gramineus (AG), Coptis chinensis (CC), Polygonum multiflorum (PM), Cyperus rotundus (CR) and Psoralea corylifolia (PC)-on the scopolamine (SCOP)-induced amnesia by using a passive avoidance task in rats. Of ten Chinese herbs, only PG, PNG, GE and CC prolonged the SCOP-shortened STL. These results revealed that PG, PNG GE and CC administered orally for 1 week improved the SCOP-induced learning and memory deficit in rats.

Administration, Oral↗
PubMed1983

Production of oxalic acid by some fungi infected tubers.

Oxalic acid (as oxalate) was detected in four tubers commonly used for food in Nigeria-Dioscorea rotundata (White yam), Solanum tuberosum (Irish potato), Ipomoea batatas (Sweet potato), and Manihot esculenta (cassava). Whereas healthy I. batata had the highest oxalic acid content, healthy M. esculenta contained the lowest. When all tubers were artifically inoculated with four fungi-Penicillium oxalicum CURIE and THOM, Aspergillus niger VAN TIEGH, A. flavus and A. tamarii KITA, there was an increase in oxalate content/g of tuber tissue. The greatest amount of oxalate was produced by P. oxalicum in D. rotundata tuber. Consistently higher amounts of oxalate were produced by the four fungi in infected sweet potato tuber than in any other tuber and consistently lower amounts of oxalate were produced by the four fungi in Irish potato tuber. Differences in the carbohydrate type present in the tubers and in the biosynthesis pathway are thought to be responsible for variation in the production of oxalate in the different tubers by the four fungi used.

Fungi↗
PubMed2004

Attenuating effect of a traditional korean formulation, Paeng-Jo-Yeon-Nyeon-Baek-Ja-In-Hwan (PJBH), on hydrogen peroxide-induced injury in PC12 cells.

The Paeng-Jo-Yeon-Nyeon-Baek-Ja-In-Hwan (PJBH) prescription is a dried decoctum consisting of a mixture of 18 medicinal herbs that include Semen Biotae, Fructus Torilis seu cnidii, Fructus Rubi, Herba Dendrobii, Radix Morindae officinalis, Cortex Eucommiae, Radix Aspragi, Radix Polygalae, Radix Dipsaci, Ramulus Cinnamomi, Rhizoma Acori graminei, Rhizoma Alismatis, Rhizoma Dioscoreae, Radix Ginseng, Radix Rehmanniae preparata, Fructus corni, Fructus Schisandrae and Herba Cistanches. The effect of PJBH extracts on H2O2-induced toxicity in the rat pheochromocytoma line PC12 was examined by measurements of cell lesion, level of lipid peroxidation and antioxidant enzyme activities, since free radicals are involved in neurodegeneration in Alzheimer's disease (AD). After a 30 min exposure of the cells to H2O2 (150 microM), a marked decrease in cell survival, activities of glutathione peroxidase and catalase as well as an increased production of malondialdehyde (MDA) were found. Pretreatment of the cells with PJBH (0.5-10 microg/ml) prior to H2O2 exposure significantly elevated cell survival, antioxidant enzyme activities and resulted in a decrease in the level of MDA. The effects of the PJBH on hydrogen peroxide-induced injury in PC12 cells were also examined. PJBH had a remarkable elevating effect on catalase and GSH-Px activities as well as cell survival, suggesting that cytoprotective effects of the PJBH are involved in stimulation against intermediate concentrations of H2O2-induced PC12 cell injury. The above-mentioned neuroprotective effects were also compared with the effect of tacrine. The results suggest that PJBH has potential for use as a novel neuronal therapeutic agent.

Alzheimer Disease↗
PubMed2002

Evaluation of the antimicrobial potential of medicinal plants from the Ivory Coast.

A total of 148 crude ethanol extracts from 115 plant species were tested in vitro against Gram-negative strains (Escherichia coli, Pseudomonas aeruginosa) and the Gram-positive Staphylococcus aureus and Enterococcus faecalis. Moreover, they were submitted to antifungal assays against Candida albicans and Cladosporium cucumerinum, a human and a plant pathogenic microorganism, respectively, known to be good indicators of antifungal activity. No activity was detected against the Gram-negative bacteria, while 14.8% and 10.8% of the extracts showed Gram-positive bactericidal or bacteriostatic effects on S. aureus and E. faecalis, respectively. An antifungal activity was observed with 15 extracts (10.1%). Two species were particularly active against the fungi: Dioscorea minutiflora and Erythrina vogelii. The young tubers of D. minutiflora contain metabolites with a specific effect on fungi and were not active against the bacteria. On the other hand, E. vogelii was highly effective against the Gram-positive bacteria and the fungi.

Anti-Bacterial Agents↗
PubMed1996

The evolution of angiosperm seed proteins: a methionine-rich legumin subfamily present in lower angiosperm clades.

Analysis of legumin-encoding cDNAs from Dioscorea caucasica Lipsky (Dioscoreaceae) and from Asarum europaeum L. (Aristolochiaceae) shows that there is an especially methionine-rich legumin subfamily present in the lower angiosperm clades including the Monocotyledoneae. It is characterized by a methionine content of 3-4 mol% which is roughly triple the methionine proportion of most other legumins. These "MetR" legumins, if present, still have to be detected in the higher angiosperms including the important seed crops. Evolutionary analysis suggests that the MetR legumins are the result of a gene duplication allowing the differentiation of legumin genes according to their sulfur content. The duplication event must have taken place before the split into mono- and dicotyledonous plants but probably after the separation of angiosperms and gymnosperms.

Amino Acid Sequence↗