• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.4
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• pp.297-300
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• 2002

Endogenous ABA and batatasins were first quantified in the stored tubers and bulbils of the Chinese yam, Dioscorea opposita Thunb. cv. 'Tsukune' by GC-MS with comparison of internal standard, and sugar content was also analyzed by HPLC with comparison of external standard. Endogenous ABA content in stored tubers and bulbils was rapidly decreased as storage period prolonged. ABA content of the bulbils was always higher than that of tuber during storage periods. All batatasins of stored tubers and bulbils at 30 days after storage decreased steadily compared to 120 days after storage. On the contrary, batatasin-Ⅲ of the stored tuber and bulbils was only decreased at 60 days after storage. In Dioscorea opposita Thunb. cv. 'Tsukune' like D. japonica, D. alata, and D. bulbifera, may be controlled by endogenous batatasins and ABA, In these compounds, batatasins rather than ABA might be closely related to dormancy-inducing compound during dormancy of the Chinese yam, Dioscorea opposita Thunb. cv. Tsukune.

• Journal of Life Science
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• v.34 no.3
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• pp.153-159
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• 2024

Dioscorea alata L, commonly known as "tropical yam" is the most widely consumed yam species among the 650 yam species belonging to the Dioscoreacea family. It is extensively cultivated in tropical and subtropical regions and is a major food source in Africa and India. Also, it is used for medicinal purposes, particularly in China and Taiwan, for its anti-inflammatory properties. In comparison to other yam varieties such as D. batatas or D. opposita, the tropical yam has gained popularity in Korea due to its higher yield per unit area. In this study, the nutritional characteristics and anti-thrombosis activity of the aerial bulbils of D. alata L. tropical yam were compared to those of D. opposita. The results showed that the aerial bulbils of tropical yam exhibited nutritional characteristics and potent anticoagulant activity compared to those of domestic yam varieties. The bulbils extract of tropical yam showed superior anticoagulant activities against thrombin, prothrombin and blood coagulation factors. Furthermore, the bulbils extract of tropical yam exhibited strong platelet aggregation inhibition at 0.25 mg/ml and showed no hemolytic activity up to a concentration of 2.5 mg/ml. These findings suggest the potential development of high-value anti-thrombosis agents utilizing the aerial bulbils of tropical yam.

• Korean Journal of Medicinal Crop Science
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• v.14 no.3
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• pp.163-167
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• 2006

The various cultural practices of bulbils were tested for seed tuber production in Chinese yam (Dioscorea batatas Decne.). To obtain amount of seed tuber, yam bulbils were sowed from early April to early May. The late sowing reduced average tuber weight, and consequently the amount of small tubers less than 20g increased highly. The optimum seeding rate of bulbils was 200 kg/10 a for production of seed-tubers. The average tuber weight was decreased according to increasing of seeding rate, so the amount of small tubers among total harvested tubers increased greatly at high seeding rate. Tuber size was affected by bulbil size. Seeding of the larger size bulbils result in increased sprouting rate, each tuber weight and tuber yield per unit area.

• Microbiology and Biotechnology Letters
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• v.37 no.3
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• pp.266-272
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• 2009

The annual productions of yam and its aerial bulbils are estimated to 5,000 and 2,500 ton, respectively. But the majority of bulbils had been discarded without specific use. In this study, methanol extract and its organic solvent fractions were prepared from bulbils of Dioscorea batatas Decne, and their antimicrobial, antithrombin, and antioxidant activities were evaluated, respectively. The methanol extract contained 58.98% of water-soluble materials as like yam's extract. But the bulbils's extract contained 12-folds of total polyphenol and 3.4-folds of total flavonoids compared than yam's extract, respectively. For antimicrobial activity the hexane and ethyl acetate fraction showed strong antibacterial activity at $500{\mu}g/disc$ concentration against gram-negative and gram-positive bacteria. Antifungal activity was not observed in any fractions. Strong antithrombin activity was found in the hexane fractions. At 4.8 mg/mL concentration thrombin time (TT) was over 300 sec, which is 4-folds extended than the TT of yam. In a while, the ethyl acetate fraction showed strong DPPH scavenging activity ($IC_{50}$ of $38.1{\mu}g/mL$), SOD-like activity and reducing power, which are comparable to vitamin C or BHT. Our results suggest that the bulbils of yam as yam tuber have useful bio-activities, such as antibacterial, antithrombosis, and antioxidant activity.

• Journal of Life Science
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• v.16 no.4
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• pp.647-652
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• 2006

Plants of the genus Dioscorea have long been used as oriental folk medicine, and Dioscorea batatas Decne has been cultivated for healthy food in Korea. Although the bulbils were produced 2,000 ton annually, there are few reports for bioactive compounds in bulbils. In this study, three phenanthrenes and two phenanthraquinones were isolated from the aerial bulbils of D. batatas Decne, and their structures were elucidated. Among them, compound 2 (6-hydroxy-2,7-dimethoxy-1,4-phenanthraquinone) has not been reported previously. Evaluation of antimicrobial activities based on disk-diffusion assay, MIC and MFC showed the compound 12 (6,7-dihydroxy-2,4-dimethoxyphenanthrene) has strong antimicrobial activity with $25\;{\mu}g/ml$ of MIC and MFC against Candida albicans. Our results suggested that compound 12 has a potent antifungal activity, and the antimicrobial activity and its spectrum are modulated by hydroxylation and methoxylation of phenanthrene ring moiety of the compound.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.3
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• pp.250-254
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• 2011

The study was carried out to evaluate the affect of proton beam radiation on production of bulbil and tuber including change of endogenous gibberellins, of Dioscorea opposita Thunb. The yield of bulbils and tubers from non- and irradiated D. opposita Thunb at doses of 5, 10, 15 and 20 Gy were determined. Endogenous gibberellins were also quantified by GC/MS analysis. D. opposita tubers irradiated at 15 Gy produced higher bulbil production than non-irradiated plants. Enlarged bulbil (above size diameter 4 mm) was significantly increased at 15 Gy. Bioactive endogenous $GA_4$ was dominant in bulbils and tubers irradiated with proton beam rather than $GA_1$. Major gibberellins biosynthetic pathways in bulbils and tubers of D. opposita plants were non C-13 hydroxylation route. From the results of this study, 15 Gy proton beam radiation was suggested as an optimal dose that can produce high amounts of bulbil for mass production of D. opposita plant.

• Korean Journal of Plant Resources
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• v.25 no.2
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• pp.200-208
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• 2012

The bulbil of the $Dioscorea$ $species$ is produced, the amount of which is 2,000 tons annually, but it has been discarded without specific use. In this study the antioxidant and antimutagenicity of bulbil of the $Dioscorea$, which compared to bulbil of Danma($Dioscorea$ $japonica$ Decaisne) and Jangma($Dioscorea$ $batatas$ Decaisne), a major domestic cultivation species. The study was done by extracting bulbil of the Dioscorea methanol and the methanol extracts was re-extracted with chloroform, ethyl acetate, $n$-butanol and water. In methanol extract of Danma and Jangma, polyphenolic compounds contained 2.2 and 3.9 mg/g extract, respectively. The ethyl acetate fraction of Danma and Jangma had higher polyphenolic contents of 33.9 and 39.1 mg/g, whereas water fractions were much lower at 2.4 and 5.8 mg/g. Determination of antioxidant activity showed that the ethylacetate fraction strong DPPH radical scavenging activity and ABTS radical scavenging activity. The inhibitory effects of methanol extracts and chloroform, ethylacetate, $n$-butanol, water fraction from bulbil of Danma and Jangma on the mutagenicity in 1-NP, $AFB_1$, Trp-P-1 were investigated using $S.$ $typhimurium$ TA98. Danma and Jangma cultivars decreased the reverse mutation induced by 1-NP, $AFB_1$, Trp-P-1 in $S.$ $typhimurium$ TA98. The fraction of chloroform and ethylacetate showed strong inhibitory effects, in a dose dependant manner against the mutagenicities induced by 1-NP, $AFB_1$, Trp-P-1 in $S.$ $typhimurium$ TA98.

• YAKHAK HOEJI
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• v.54 no.2
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• pp.106-111
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• 2010

The chemical structures of eight compounds purified from two plants (Polygala tenuifolia Willdenow and Dioscorea batatas Decene) were determined and their anti-microbial activity against three microbial strains (Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans) was tested. The three micro organisms were cultured in 96-well plates or Petri dishes without (control) or with the eight compounds added at concentrations of 100 to 0.01 ${\mu}M$ (wt/vol). The growth of the microorganisms in the medium was examined after a 24-h incubation. The inhibitory effect of each compound on the growth of the microorganisms was calculated from the optical density measured at 595 nm, turbidity, and size of the inhibition zone around the treated paper disc. The minimum inhiitory concentration (MIC) of compounds 4 to 7 against S. aureus was 0.08, 0.05, 1.3 and 0.02 ${\mu}M$, respectively, and 0.09, 0.1, 0.2 and 100 ${\mu}M$ against C. albicans. The $IC_{50}$ (50% inhibition) values of compounds 5 and 6 were 3.1 and 6.4 ${\mu}M$ against S. aureus, respectively, and 10 and 2.4 ${\mu}M$ against C. albicans. Therefore, compounds 4 to 6 were the most potent anti-microbial agents among the eight compounds tested.