• Food Science and Preservation
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• v.17 no.3
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• pp.391-397
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• 2010

Yams (Dioscorea spp.) have been used as medicinal and edible resources worldwide. In the present study, methanol extracts were prepared from various kinds of yam, including D. batatas (Gyeongbuk No. 1 and No. 4), D. alata L. (Gyeongbuk No. 5 and No. 6), and D. bulbifera and D. nipponica, and the antioxidant, antithrombin, and antimicrobial activities of these extracts were evaluated. The water content of the various yams was 54.7~83.2% (D. batatas> D. alata L.>D. nipponica>D. bulbifera) and the methanol extracts contained 0.59-1.59% (w/v) solid matter (D. alata L.>D. batatas >D. nipponica>D. bulbifera). The mean concentrations of total polyphenols, total flavonoids, and total sugars in the different types of yam were 49.82 mg/g, 9.79 mg/g, and 173.81 mg/g, respectively. Analysis of DPPH radical-scavenging activity showed that D. alata L. Gyeongbuk No. 6 had a strong antioxidant capacity (IC50=$142.30{\mu}g/mL$), whereas the other yams showed reduced levels of activity (IC50=371-$486{\mu}g/mL$). D. alata L. Gyeongbuk No. 6 showed a strong antithrombin activity against human thrombin. Upon treatment with a D. alata methanol extract (1.5 mg/mL), thrombin time was increased 7.35-fold compared with that when methanol alone was used. In an antimicrobial activity assay, the D. nipponica extract showed moderate antibacterial activity against Bacillus subtilis, Staphylococcus aureus, Proteus vulgaris, and Salmonella typhimurium. Our results indicate that different varieties of Dioscorea spp., including D. batatas, have useful biochemical attributes, including antioxidant, antithrombin, and antibacterial activities.

• Journal of Life Science
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• v.21 no.8
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• pp.1142-1148
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• 2011

This study was conducted to investigate antioxidative and physiological activities of ethanol extracts concentration from Monascus-Fermented Chinese Yam (MFCY). The ethanol extracts from MFCY were measured to examine pigment, monacolin K content, total polyphenol content, DPPH radical scavenging activity and angiotensin converting enzyme inhibitory effects. In this study, the results show that Monascus sp. MK2, with Dioscorea batatas Dence. as the substrate, can produce pigments (red, orange, and yellow), monacolin K content, total polyphenol content and DPPH radical scavenging activity at 13.48 (red), 11.66 (orange), 12.77 (yellow), 462.78 (mg/kg), 658.8 (mg/kg) and 92.8% in EtOH extract, respectively. In addition, ACE inhibitory activity was shown to be 74.55% in EtOH extract. Therefore, it can be concluded that Dioscorea batatas Dence is the best fermentative substrate for Monascus species to produce secondary metabolites as biomedicinal substances.

• Journal of Microbiology and Biotechnology
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• v.32 no.8
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• pp.976-981
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• 2022

Phenanthrenes are bioactive phenolic compounds found in genus Dioscorea, in which they are distributed more in peel than in flesh. Recent studies on phenanthrenes from Dioscorea sp. peels have revealed the potential for valuable biomaterials. Herein, an analytical method using high-performance liquid chromatography (HPLC) for quantitation of bioactive phenanthrenes was developed and validated. The calibration curves were obtained using the phenanthrenes (1-3) previously isolated from Dioscorea batatas concentrations in the range of 0.625-20.00 ㎍/ml with a satisfactory coefficient of determination (R²) of 0.999. The limit of detection (LOD) and the limit of quantification (LOQ) values of the isolated phenanthrenes ranged from 0.78-0.89 and 2.38-2.71 ㎍/ml, respectively. The intraday and interday precision ranged from 0.25-7.58%. The recoveries of the isolated phenanthrenes were from 95 to 100% at concentrations of 1.25, 2.5, and 5.0 ㎍/ml. Additionally, phenanthrenes (1-3) were found in all investigated peel extracts. Hence, the developed method was encouraging for the quantitative analysis of phenanthrenes in genus Dioscorea.

• 한국약용작물학회:학술대회논문집
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• 2007.05a
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• pp.181-182
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• 2007

• Journal of Physiology & Pathology in Korean Medicine
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• v.27 no.2
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• pp.183-188
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• 2013

Ultraviolet (UV) B irradiation induces the production of matrix metalloproteinases (MMPs), which are responsible for the degradation or synthesis inhibition of collagenous extracellular matrix in connective tissues, causing skin photoaging. In this study, we examined the inhibitory effect of MMP-1 expression of yam extract in tumor necrosis factor-alpha (TNF-${\alpha}$)-stimulated human dermal fibroblast neonatal (HDFn) cell and preventive effect of UVB-induced damage in hairless mice skin. The synthesis of procollagen and the release of MMP-1 in HDFn cells were measured by EIA kit and MMP-1 assay kit, respectively. UVB radiation was applied to the backs of the mice three times a week for 8 weeks. Mice were randomly divided into three groups, and were topical application with the Dioscorea batatas (DB, 6%) or vehicle. Reduction of TNF-${\alpha}$-induced procollagen synthesis was increased by DB (50 ug/ml), which was higher than positive control group (TGF-${\beta}$). Also, pre-treatment of HDFn cells with DB inhibited TNF-${\alpha}$-induced release of MMP-1. In vivo study, we found that preventive effect of DB against UV-induced epidermal thickness. DB suppressed the expression of MMP-3 and MMP-13 induced by UVB irradiation. Our results show that DB have preventive effect of UV-induced skin damage in hairless mice.

• Journal of the East Asian Society of Dietary Life
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• v.22 no.2
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• pp.231-238
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• 2012

$Dioscorea$ $batatas$ Decne is a type of yam that eaten raw and used as a traditional oriental medicine in Asian countries. In this study, we evaluated the functional effects of yam water extracts on body weight levels and serum lipid concentrations in mice fed high fat diet. Mice were divided into four groups: normal diet control (ND), high fat diet control (HFD), HFD+yam extract 100 mg/kg (HFD-Y100), and HFD+yam extract 200 mg/kg (HFD-Y200). Yam extract was administrated orally to mice fed a high fat diet for 5 weeks. Treatment with yam extract significantly reduced body weight levels and energy efficiency in a dose-dependent manner in HFD-fed mice. Yam extract also attenuated serum levels of triglyceride, total cholesterol, and LDL-cholesterol, as well as organ weights of liver and abdominal adipose tissue in mice fed a high fat diet. Moreover, blood levels of glucose, insulin, and leptin significantly decreased in a dose-dependent manner upon administration of yam extract. Blood activities of GPT, GOT, and LDH were lower in the yam extract-treated groups compared to the HFD group. These results indicate that yam water extract may reduce elevated body weight and serum lipid concentrations in mice fed a high fat diet, suggesting its usefulness as a functional food for reducing body fat and hyperlipidemia.

• Korean Journal of Food Science and Technology
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• v.50 no.2
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• pp.191-197
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• 2018

This study investigated the influence of starch extraction (ST-EX) solutions on the extraction yield and characteristics of Chinese yam (CY) starches from domestic Dioscorea batatas. Ascorbic acid (VitC), $Na_2S_2O_3$, $NaHCO_3$, and $Na_2CO_3$ were used as ST-EX solutions (0.4%, w/v). The extracted CY starches were examined for ST-EX yield, chemical composition, size distribution, X-ray diffraction, solubility, swelling power, gelatinization, and pasting viscosity. The highest ST-EX yield was obtained from $NaHCO_3$, followed by VitC. Lower protein content, relative crystallinity, and gelatinization enthalpy were found in CY starches from alkaline ST-EX solutions ($NaHCO_3$ and $Na_2CO_3$). Size distribution and gelatinization temperature did not generally differ for CY starches from the different ST-EX solutions. Pasting viscosities increased in the order from $Na_2CO_3$ > $Na_2S_2O_3$ > $NaHCO_3$ > VitC ST-EX solutions. Thus, VitC may be most appropriate to extract CY starch from Dioscorea rhizomes, considering its ST-EX yield, total starch content, and variation in pasting viscosity.

• Korean Journal of Medicinal Crop Science
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• v.6 no.3
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• pp.170-175
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• 1998

This study was conducted to determine the effect of seminal sections of tuber and staking methods on growth and yield of a chinese yam (Dioscorea batatas Decne). Tuber was divided into top head, head, median and tail which were used as seminal sections of tuber. The emergence of shoots was delayed in median and tail sections by 15 days as compared with top head and head sections. Sections from head and tail exhibited yield increase as high as 16 and 15%, respectively, compared to top head sections. Although flowering and bubil setting occurred almost at the same time in all staking methods, fresh weight of stem and leaves was higher in ${\wedge}-$, I-type stake supporting net than in the conventional stake. In the cultivar, 'Dan-ma', tuber yield didn't show a meaningful increase statistically by all staking methods. But ${\wedge}-$ and I-type stake supporting net increased the yield of the cultivar, 'Jang-ma', as high as 11 and 8%, respectively, compared to conventional stake. Also I-type stake was ideal supportor of net, considering the cost of management.

• Archives of Pharmacal Research
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• v.29 no.5
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• pp.348-353
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• 2006

In this study, a 40% ethanol extract of Chinese yam flour (Dioscoreae rhizoma), containing $177{\pm}58{\mu}g/mL$ of dioscin, was tested in order to evaluate its pharmacological effects on the gastrointestinal tracts of Sprague-Dawley rats. Via the ingestion of the Chinese yam extract, the secretion of gastric acid was suppressed in the rats, and gastrointestinal motility increased by as much as 10%. The fecal quantity of rats fed on the Chinese yam extract also increased, by more than 40% as compared with that of the controls. The Chinese yam extract was found not to affect the growth of normal intestinal bacteria. However, a great deal of lactose-fermenting bacteria was observed in the fecal samples of rats fed for 6 weeks on 2% Chinese yam extract. This finding would appear to suggest that Chinese yam extract not only induces an improvement in digestive capability, but also affects the conversion of some intestinal flora to helpful bacteria. Our serochemical analyses indicated that serum glucose, neutral lipid, and total cholesterol levels were reduced to some degree by long-term feeding on Chinese yam extract. This finding bolsters the notion that Chinese yam extract may prove helpful as a digestion-aiding agent for patients suffering from hyperglycemia or hyperlipidemia.

• Korean Journal of Food Science and Technology
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• v.39 no.6
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• pp.708-714
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• 2007

In this study, the 163 edible plants that are permitted as foods by the Korea Food and Drug Administration, were extracted in methanol. Following extration, their macrophage immunostimulating effects (MIE) were examined using a macrophage from BALB/C mice at four different concentrations of plant extract, such as $10\;{\mu}g/mL$, $100\;{\mu}g/mL$, $500\;{\mu}g/mL$, and $1,000\;{\mu}g/mL$, in vivo. Forty-two samples significantly showed MIEs. Among them, 20 samples had increased MIEs at higher than 10%, as compared to the negative control group. Nineteen samples had increased MIEs at two of the plant extract concentrations, and 3 samples [Allium schoenoprasmum (chive), Aralia elata (fatsia), Capsosiphon fulvescens (seaweed fulvescens)] had increased MIEs at three of the concentration conditions. In particular, Dioscorea batatas (yam) showed MIEs at all concentrations, as well as slightly higher MIEs as compared to the positive control group. Therefore, Dioscorea batatas was evaluated to be an excellent MIE.