• Korean Journal of Weed Science
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• v.12 no.4
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• pp.374-379
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• 1992

Response of medicinal plants(58 species in 28 families) cultivated or naturally grown in Korea on paraquat (1,1'-dimethyl-4,4'-bipyridinium ion) was determined. All the plants, except for Jiwhang(Rehmannia glutinosa Liboch.) were killed by paraquat at 0. 8kg $ha^{-1}$. Jiwhang showed a great resistance to paraquat. The phytotoxic effect did not occur in Jiwhang with paraquat applied at 3.2kg $ha^{-1}$. Only 10% growth inhibition of Jiwhang was obtained at 4.8kg $ha^{-1}$. Normal growth of Jiwhang also occurred when at 0.8kg $ha^{-1}$ of paraquat different application dates from 2 leaf stage(LS) to 8 LS and/or five-repeated applications at 20-day intervals starting from 3 LS were employed. However, Jiwhang was completely killed by glyphosate[N-(phosphonomethyl) glycine], 2,4-D[2,4-dichlorophenoxy) acetic acid], and dicamba[3,6-dichloro-2-methoxy benzoic acid]+2, 4-D at the respective recommended rates.

• Journal of Life Science
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• v.18 no.4
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• pp.435-440
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• 2008

Random amplified polymorphic DNA (RAPD) markers were used to identify the genetic diversities among and within varieties and landraces of Rehmannia glutinosa. Polymorphic and reproducible bands were produced by 10 primers out of total 20 primers used in the experiment. In RAPD analysis of the 11 genotypes, 64 fragments out of 73 amplified genomic DNA fragments were polymorphic which represented an average 6.4 polymorphic fragments per primer. Number of amplified fragments with random primers ranged from 2 (OPA-1) to 13 (OPA-11) and varied in size from 200 bp to 1,400 bp. Especially, OPA-10, OPA-11 and OPA-19 primers showed specific bands for varieties of Korea Jiwhang and Jiwhang il ho, which could be useful for discriminating from other varieties and landraces of R. glutinosa. Percentage polymorphism ranged from a minimum of 50% (OPA-1) to a maximum of 100% (OPA-11), with an average of 87.7%. Similarity coefficients were higher in the genotypes of Korea Jiwhang and Jiwhang il ho than in other populations. In cluster analysis, genotypes of Korea Jiwhang, Jiwhang il ho, and Japanese accession were separated from those of other varieties and landraces. Average of genetic diversity within the population $(H_S)$ was 0.110, while average of total genetic diversity $(H_T)$ was 0.229. Across all RAPD makers the $G_{ST}$ value was 0.517, indicating that about 52% of the total genetic variation could be explained by RAPDs differences while the remaining 48% might be attributable to differences among samples. Consequently, RAPD analysis was useful method to discriminate different populations such as domestic varieties and other landraces. The results of the present study will be used to understand the population and evolutionary genetics of R. gllutinosa.

• Food Science and Biotechnology
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• v.18 no.1
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• pp.202-206
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• 2009

Drying characteristics of fresh Korean-type rehmannia (jiwhang) noodle was investigated to determine drying kinetic parameters under the experimental conditions of 5 temperatures (30, 40, 60, 80, and $90^{\circ}C$). Drying curve of the noodle showed a biphasic pattern of decrease in drying rate with initial rapid drying followed by slow dehydration as the progress in drying. In all drying conditions, only falling drying rate period was observed and the drying rate of the noodle was greatly influenced by the drying temperature. The effective diffusion coefficients ($D_{eff}$) were determined by the diffusion model and their temperature dependency was determined using an Arrhenius equation. The activation energy ($E_a$) values for the drying of the noodle were 19.94 and 21.09 kJ/mol at the initial and the latter stage of dehydration, which were comparable to those of pasta or Japanese udong dehydration.

• Korean Journal of Plant Tissue Culture
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• v.25 no.4
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• pp.273-276
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• 1998

Chinese foxglove (Rehmannia glutinosa) is receiving much attention as one of the principal medicinal crops and the crude drug damand expands rapidly. This study was conducted to obtain the basic breeding information of Chinese foxglove. Meristem culture was employed for virus free seedling production and miropropagation. Both Jiwhang 1 and domestic local were severely infected by potexvirus and TMV. Several growth regulators were used for the virus free stock production from Jiwhang 1 and Danyang local. Shoot formation and callus induction from the meristem culture seemed to be influenced by the content of various kinds of plant growth regulators. Kinetin supplement was the most effective on shoot formation and NAA addition was good on callus induction among the treatments. The acquired virus free stocks were confirmed using transmission electron microscope and indicate plants.

• 한국약용작물학회:학술대회논문집
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• 2010.10a
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• pp.201-202
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• 2010

• The Journal of Korean Medicine
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• v.25 no.4
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• pp.129-138
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• 2004

Objective : Treatments for patients with mental retardation and pervasive developmental disorders are not curative, and are designed to help those with disabilities adjust to their environments and daily demands. As clinicians, the present authors tried to find agents with potentially curative properties. Among the numerous herbal formulations available, we chose and assessed Gami-jiwhang-tang (GJT) in the hope that it would improve cognitive development of children. Methods : Subjects were typically-developing healthy, 7- to 8-year-old boys and girls living in Seoul, Korea. The experimental group took GJT for six weeks and was followed up six weeks after discontinuation of GJT. The control group was assessed at the same intervals but did not receive placebos. To measure the effects of GJT, neuropsychological tests and intelligence test were taken before commencing GJT and twelve weeks later. Resulets and Conclusion : For all of the ANOVAs, the treatment by time interaction terms was not significant. However, the experimental group showed the tendency to be progressed in most subscales compared with the control group, especially on performance intelligence, visual organization, and verbal fluency. Conclusion : Although GJT failed to reveal significant improvement in cognition, we remain hopeful about the compound and believe that it should be evaluated by a double-blind, placebo-controlled trial in the future.

• Korean Journal of Medicinal Crop Science
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• v.7 no.3
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• pp.213-217
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• 1999

Seed coating and pelleting techniques have been used in many crops to improve the germination vigor of tiny and light seeds. Cultivated Chinese-foxglove (Rehmannia glutlnosa) has been infected by various types of virus derived from vagetative propagation of rootstock. Seed characteristics and alginate-coated seed germination rate have been investigated to get basic information for healthy seedling production through seed propagation. Chinese-foxglove showed different numbers of seeds per pod from 61 in Seocheon local to 207 in Jiwhang 1 and 1,000grain weight also varied from 70mg of Seocheon local to 130mg of Jiwhang 1. Seeds of Chinese-foxglove has dormancy because that seed collected last year more stimulated than that of this year at germination test. Optimum alginate concentration for pellected seeds germination was 2%.

• Food Science and Biotechnology
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• v.18 no.6
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• pp.1464-1469
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• 2009

Jiwhang (Rehmannia glutinosa), one of the most widely used medicinal herbs, was dried with various methods such as sun drying, hot air drying, vacuum drying, and freeze drying methods, and their effects on the antioxidant capacity in relation with the content of total phenolic compounds were studied with a steamed-and-dried rehmannia (sookjiwhang) for comparison. Generally, total phenolic contents decreased significantly by all of the drying treatments except the steamed-and-dried rehmannia, in which total phenolic contents increased 2.4 fold compared with fresh rehmannia. Content of verbascoside, a functional phenolic compound, was the highest in the freeze-dried rehmannia ($177.97{\pm}0.02\;{\mu}g/g$ d.m.) followed by vacuum-dried ($105.55{\pm}0.07\;{\mu}g/g$ d.m.), hot air-dried ($23.01{\pm}0.02\;{\mu}g/g$ d.m.), and sun-dried ($4.89{\pm}0.13\;{\mu}g/g$ d.m.) ones comparable to the fresh rehmannia ($80.15{\pm}1.26\;{\mu}g/g$ d.m.). Antioxidant capacity determined by both 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis (3-ethyl-benzthiazoline-6-sulphonic acid) (ABTS) methods agreed with the result of total phenolic contents, that is, the antioxidant capacity was the highest in the steamed-and-dried rehmannia followed by fresh rehmannia, vacuum-dried, hot air-dried, sun-dried, and freeze-dried ones. Conclusively, the total phenolic contents and antioxidant capacity of rehmannia were greatly affected by the drying methods used.

• Food Science and Preservation
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• v.11 no.2
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• pp.282-285
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• 2004

This experiment was carried out to investigate the cost reduction of rhizome through the stable storage of Jiwhang #1(Rehmannia glutinosa Libosch). The growth characteristics of Jiwhang #1 are different from those of local Rehmannia glutinosa L. varieties in Korea. Various storage methods was introduced and analyzed for 120 days. Among storage methods, changes in mean daily temperature in storage location were the least from 7.2 to 13.8$^{\circ}C$ in underground storage, while those were wide in styrofoam box filled with soil, and changes in mean daily relative humidity were the highest 98.2% in underground storage. As the storage period increased, the rhizome brix and the rate of rhizome loss and spoiled rhizome increased. The brix and loss rate of rhizome were higher in net sack filled with hull and styrofoam box filled with hull, but the rate of spoiled rhizome was the greatest in underground storage among storage methods. As the storage period increased, the hardness of rhizome epidermis increased, while that of rhizome endodermis decreased.

• Food Science and Biotechnology
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• v.16 no.5
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• pp.771-777
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• 2007

Sliced and whole root of rehmannia were dehydrated in a laboratory dryer at 40, 60, 80, and $100^{\circ}C$ to evaluate the kinetic parameters for dehydration of rehmannia. The drying curves of both samples were characterized by a falling-rate drying period only. Sliced rehmannia dried 1.1 to 3.1 times faster than whole root of rehmannia depending on drying temperature. Equilibrium moisture content (EMC) of rehmannia samples at the drying temperature tested were 0.069-0.078 g water/g dry solid, which was coincided with the monolayer moisture content (0.06 and 0.07 g water/g dry solid) evaluated from desorption isotherms using GAB (Guggenheim-Anderson-de Boer) model. A logarithmic model for thin layer drying was applied to evaluate the drying time to reach EMC ($t_{EMC}$) and drying constant (k). The effect of temperature on $1/t_{EMC}$ and k was described by the Arrhenius model with activation energy values of 32.56 and 47.14 kJ/mol determined using the former parameter, and 34.27 and 38.26 kJ/mol determined using the latter parameter for sliced and whole root of rehmannia, respectively.