일반적으로 지황[Rehmannia glutinosa (Gaertn.) Libosch ex Steud.]은 플러그 묘를 사용하지 않고 노지에 파종한다. 플 러그 묘는 발아 촉진과 이식이 편리한 장점이 있다. 그러나 지 황의 플러그 육묘를 이용한 번식에 관한 연구는 미흡한 실정 이다. 본 연구는 공정육묘 방법 확립을 위한 지황의 최적 종근 길이, 굵기 및 파종 방향을 조사하기 위해 수행되었다. 종근의 길이는 1, 2, 3cm로 구분하였고, 굵기는 각각 0.3－0.5, 0.6－ 1.0, 1.1－1.5cm로 구분하였다. 그리고 종근은 수직 및 수평 방향으로 파종하였다. 종근 길이 1cm 처리에서 생존율이 유 의적으로 낮았다. 엽장, 엽폭, 엽수, SPAD, 엽면적, 지상부와 지하부의 생체중 및 건물중은 3cm 길이에서 가장 높았다. 지 황의 종근 굵기가 감소할수록 묘의 생육이 증가하는 경향을 보였다. 지황의 종근을 수평 방향으로 파종하였을 때 엽장, 엽 폭, 엽수, 엽면적은 수직 방향보다 유의하게 높았다. 결론적으 로 지황 종근을 플러그 트레이 파종할 때, 길이 3cm로 절단한 뒤 굵기 1.0cm 이하의 종근을 수평 방향으로 파종하는 것이 적절한 방법으로 판단된다.

The aging treatment was applied to Rehmannia glutinosa rhizome (RGR) to improve the digestibility by the enzymatic hydrolysis of undigestible sugars. However, RGR spoils easily during the aging treatment. Thus, the purpose of this study was to investigate the influence of ethanol addition as preservatives on sugars and microbial growth of aged RGR. The RGR was treated with the addition of ethanol (0~10%) at 55℃ for eight days. Reducing, free sugars, and total bacterial counts of RGR with ethanol concentrations were analyzed during the aging periods. The aged RGR with 0-2% ethanol appeared spoiled in appearance, and total bacterial counts of these samples increased from 1.1×105 to 2.2×107 CFU and then decreased again. When treated with 4~10% ethanol, the total bacterial counts of aged RGR decreased by more than 99.9% at eight days. In all samples, reducing and digestible sugars increased, and stachyose decreased by the aging treatment. Sucrose content was highest in the 6% ethanol sample (18.2% at six days). These results indicate that the ethanol addition can be applied to the aging treatment of the RGR for improving qualities (sweetness, digestibility, and microbial growth), and can be considered for the stable production of high quality aged RGR.

지황은 현삼과(Scrophulariaceae)에 속하는 다년생 초본식물 Rehmannia glutinosa(Gaertn.) DC.로 서 한의학에서는 뿌리를 지황(地黃)이라는 한약재로 이용하고 있다. 지황은 선지황(鮮地黃), 생지황(生 地黃), 숙지황(熟地黃) 등으로 널리 사용되고 있지만 종자파종에 의한 재배보다 종근을 이용한 영양번식 으로 재배하고 있다. 종근을 이용한 재배법은 뿌리 썩음병으로 인해 종근의 관리와 생산성이 높은 고품 질의 지황 생산이 어려운 실정이다. 본 연구에서는 형태적 특징과 유전자 분석을 통해 기원이 검증된 지황 기원식물을 이용하여 정확한 기원의 무균 배양묘와 종근 생산을 위한 최적 조건을 확립하고자 하 였다. 기내배양묘 생산에 필요한 최적의 생장율과 다개체 형성율, 그리고 뿌리 형성율 및 비대조건을 탐색한 결과, WPM 배지와 1.0mg/L의 IAA와 0.5mg/L의 IBA 옥신계 생장조절제가 첨가된 배지(WPM + IAA 1.0mg/L + IBA 0.5mg/L)에서 최적 생장율과 뿌리다개체 형성율을 나타내었으며, 0.1mg/L의 NAA가 첨가된 WPM 배지(WPM + NAA 0.1mg/L)에서 가장 많은 수의 뿌리가 형성되었고 비대율도 높 게 나타났다. 이러한 최적조건에서 생산한 기내식물체는 토양 순화 후 정식하였을 경우에도 높은 뿌리 형성율과 지속적인 비대 효과를 보였다. 이상의 결과는 지황의 무균 배양묘 생산과 배양묘기반 종근 생 산을 통해 지황 대량 생산에 필요한 배양묘와 종근 생산에 유용하게 활용될 수 있을 것으로 판단되며, 고품질 지황 생산량에기여할 것으로 사료된다.

This study was conducted to investigate the preventing effects of OPB (Rehmannia glutinosa Libosch and Eleutherococcus senticosus Max extracts) and combined OPB/Calcium therapy on bone loss in ovariectomized rats. Sixty Sprague Dawley rats of 12-week-old were divided into eight groups: OVX (ovariectomized), OPBL (OPB 50 mg/kg), OPBM (OPB100 mg/kg), OPBH (OPB 200 mg/kg), OPBL/CAL(OPBL+CAL), OPBM/CAL (OPBM+CAL), OPBH/CAL (OPBH+CAL) and CAL (Calcium citrate 88.33 mg/kg+1, 25-dihydroxy-vitamin D₃33.33 IU/kg). Bone mineral density (BMD), bone mineral content (BMC), bone strength indices and cortical thickness were analyzed by peripheral quantitative computerized tomography (pQCT). pQCT scanning showed that OVX induced a significant decrease in trabecular bone mineral density and bone mineral content in the proximal tibia (-36.4 ±24%, -21.8±12.7%).These decreases were significantly prevented by the administration of OPBM and OPBM/CAL. Cortical BMD and BMC of tibia were slightly enhanced by OPB and OPB/CAL. However there was no significant difference between OVX and OPB, OPB/CAL treated group. Bone strength indices and cortical thickness were not significantly different. Our results suggest that OPB and combined OPB/Calcium therapy are effective in preventing the development of bone loss induced by ovariectomy in rats.

We performed the present study to investigate whether Rehmannia glutinosa Libosch (RG) extracts (RGX) and Eleutherococcus senticosus Max (ES) extracts (ESX) play any roles in bone metabolism. We examined cellular activities of bone cells by measurement of osteoblastic cell viability, osteoprotegerin (OPG) secretion from osteoblasts, osteoclastogenesis, and osteoclastic activity. There is no cytotoxicity from osteoblasts after treatment with RGX and ESX. The secretion of OPG from the osteoblasts showed marked increases after treatment with RGX and ESX. In addition, RGX and ESX treatment decreased the number of tartrate-resistant acid phosphatase-positive multinucleated cells and the resorption areas. RGX and ESX, when mixed at optimal ratios, induced synergic effects, in vitro. OPB, which showed synergic effects, is the extract of natural ingredients RG and ES mixed at a raw material weight ratio of 4 : 1. It can be suspected that extracts of RG and ES mixtures contains active ingredients involved in bone tissue metabolism and may be effective in improving osteoporosis.

지황(地黃)의 주(主) 약효성분(藥效成分)으로 알려져 있는 catalpol의 iridoid골격(骨格)과 glycosidic bond를 형성(形成)하는 유리당류(遊離糖類)를 확인(確認)하기 위하여 생육시기(生有時期)에 따른 무기성분(無記性分), 유리당류(遊離糖類), 회분(灰分), 엑기스 및 catalpol의 함량(含量)을 조사(調査)하였다. 수확기(收穫期)가 가까워질수록 P, K, Ca, Mg, Cu 및 회분(灰分)의 함량(含量)은 감소(減少)하였으나, Fe 및 엑기스의 함량(含量)은 증가(增加)하였다. 수확기(收穫期)가 가까워질수록 전당(全糖), sucrose 및 galactose의 함량(含量)은 감소(減少)하였으나, fructose 및 catalpol의 함량(含量)은 증가(增加)하였다.

본 연구는 지황의 플러그 육묘 재배가 생산량을 증가시킬 수 있는지 평가하고, 강원도 남부지역에 플러그 육묘를 이용한 지황 재배 시 중부지역의 직파재배만큼 생산량을 늘릴 수 있는지 알아보기 위해 수행하였다. 수량의 경우 음성 육묘재배(1,376 ㎏/10a)가 가장 높았고, 그 다음으로 평창 육묘재배(1,256 ㎏ /10a), 음성 직파재배(1,253 ㎏/10a), 평창 직파재배(923 ㎏ /10a) 순으로 나타나, 강원도에서 육묘재배시에 중부지역 직파 재배만큼 생산량을 늘릴 수 있는 것으로 나타났다. 또한, 지황은 근경 굵기가 8-12 ㎜가 중품(中品), 그 이상이 상품(上品)의 등급으로 팔리는데, 재배실험지역과 재배방법에 상관없이 모두 14 ㎜가 넘어 상품성(商品性)에도 문제가 없었다. 그러므로 생산량과 품질 조건을 고려해 볼 때, 플러그 육묘 재배를 통해 생산량을 늘릴 수 있었으며, 강원도에서 플러그 육묘를 이용한 지황 재배 시 중부지방의 직파재배와 비슷한 생산이 가능할 것으로 생각된다. 그러나 본 연구결과를 적용하기에는 늘어나는 생산비와 증가되는 수익을 고려한 경제성 분석이 더 필요할 것으로 생각된다.

본 연구는 지황이 강원도 남부지역에서 재배가 가능한 대체 작목인지 평가하기 위해 수행하였다. 수량의 경우 음성 1,848 ㎏/10a, 정선 1,571 ㎏/10a, 평창 1,485 ㎏/10a로, 2015년부터 2017년 지황 평균 단수인 838 ㎏/10a보다 높게 나타났다. 또한, 지황은 근경 굵기가 15 ㎜ 전후가 되면 상품(上品)의 등급으로 팔리는데, 강원도 재배지역 모두 15 ㎜가 넘어 상품성(商品性) 에도 문제가 없었다. 그러므로 생산량과 품질 조건을 고려해 볼 때, 현재 강원도에서 지황 재배는 가능할 것으로 생각된다. 그러나 본 연구결과를 적용하기에는 강원도의 여러 제반 사항을 고려한 경제성 분석이 더 필요할 것으로 생각된다.

Background: This study was carried out to determine the physicochemical components of Rehmannia glutinosa (RG) fermented with Rhizopus delemar. Methods and Results: Physicochemical components such as changes in moisture content, pH value, total acidity, amount of reducing sugars as well as quantity of free sugars, free amino acids, and catalpol were investigated. Result showed that, the moisture content ranged from 64.26 to 65.51%. The pH and total acidity of the fermented RG decreased significantly during fermentation. The reducing sugar content ranged from 0.10 to 1.34%. The most abundant main free sugars were identified as raffinose, xylose, glucose, fructose, and sucrose. The sucrose content in 80% ethanol and in water extracts increased during RG fermentation. In total, 26 free amino acids were detected, including seven essential amino acids. In addition, the quantity of free amino acids decreased significantly during fermentation. Finally, the catalpol content of the fermented RG was highest on the 2nd day of fermentation at 2,028.67㎎/ 100 g. Conclusions: These results indicated that fermentation of Rhizopus delemar could be used to enhance biological activity, and that fermented RG could be used as a functional material and as an edible resource in food and functional materials industries.

Background : Rehmannia glutinosa root has been commonly used as traditional medicine in Korea. This root including prepared rehmannia that is the steamed root of rehmannia can be also used as food. This study was performed to analyze the quality properties of the root and the tea with different steaming conditions to evaluate the potential as a tea. Methods and Results : For this study, we used ‘Dagang’, new variety of R. glutinosa, developed by NIHHS. The root was dried and steamed for 9 times. Every steaming, powder and extract were used for pH, antioxidant activity analysis (total phenolic acid and total flavonoid content) and sensory evaluation. As steaming repeated, pH was decreased. The total phenolic acid and total flavonoid content was increased during steaming process. In the sensory evaluation for the tea, 56% of respondents (A group) recognized the difference between 6th and 9th steaming tea correctly but 44% (B group) didn’t. The sensory scores showed that 6th and 7th steaming tea had higher overall preference scores than other samples. This tendency was more clear in the A group. Depending on the age group, there were significant different tendency among 3 age groups (20 – 30 s, 40 – 50 s, over 60 s). The youngest group was preferred 6th than 9th steaming tea. On the other hands, 9th steaming tea had more priority than 6th steaming tea in older age group. Conclusion : This study showed a potential of R. root as a tea material. The quality properties of the R. root are affected by steaming conditions and the preference tendency of tea was different depending on the age group. These data can be used to develop tea material suitable for consumer age and establish optimal steaming conditions in industrial use.

Background : In the process of developing new disease-resistant cultivar of Rehmannia glutinosa, it is essential to screen plants based on resistance to their disease. But until now, we have relied on visual inspection for selection of disease-resistant cultivar. Therefore, this experiment was carried out to establish an efficient and reliable screening system and test the resistance to leaf spot disease in R. glutinosa cultivars developed until now. Methods and Results : We have tested 11 R. glutinosa cultivars developed so far. Rootstock of R. glutinosa were sown in 20 × 20 ㎝ plastic square port and grown in green house at 25 ± 5℃ for four months and then cutting leaves were inoculated with Phoma sp. HCRD 17103 by spraying spore suspention of fungus at concentration of 1 × 107 spore/㎖. The inoculated leaves were incubated in a dew chamber at 25℃ for 48h and then transferred to glass house (25 ± 5℃, RH 80% ≥ ). After 3 - 5 days when the most susceptible cultivar had lesion area over 40%, disease severity of the cultivars was investigated on a scale of 0 - 9 (0 = healthy, 1 = 0 - 1%, 3 = 1.1 - 10%, 5 = 10.1 - 20%, 7 = 20.1 - 40%, 9 = 40.1% over). The degree of resistance was determined according to the disease index (0 and 1 = resistant, 3 = moderately resistant, 5, 7 and 9 = susceptible). As a result of experiments according to the above criteria, the disease index of cultivar Gogang, Dagang, Segang, Yeongang, Wongang, and Dahwang was 1, cultivar Togang, Daegyung, Jiwhang 1 and Goryeo was 3, cultivar Hwanggang was 9, respectively. Conclusion : From the above results, six cultivars such as Gogang, Dagang, Segang, Yeongang, Wongang, and Dahwang were resistant, four cultivar such as Togang, Daegyung, Jiwhang 1 and Goryeo were moderately resistant, and only one cultivar Hwanggang was susceptible to the leaf spot disease by Phoma sp. This experiment used only leaves and we plan to use whole plants in the future to see more accurate resistance response.

Background : Rehmannia glutinosa (RG) has been utilized as a traditional medicine in Asia. However, the development of varieties is limited and the climate is changing gradually. Therefore, it is required to develop a superior lineage suitable for this. So we have secured several species, and it is necessary to confirm the cytotoxicity of various kinds of cells for its safety and to secure safety for further utilization. Methods and Results : 11 cultivars and 21 lineages of RG were collected from Rural Development Administration (RDA) at Eumseong of Chungcheongbuk-do and national farmhouse. They were cultivated in test-research farm in RDA and used as materials. Human (THP-1 cell, human leukemia monocytic cell line) and rodent-derived immune cells (RAW264.7, murine monocyte/macrophage cell line) and hepatocytes (HepG2, human liver cell line) were used to assess cytotoxicity. Cytotoxicity was determined by using MTT assay. As a result of evaluation of cytoxicity, 11 cultivars and 21 lineages of RG were not shown cytotoxicity range from 250 - 1,000 ㎍/㎖ concentration in THP-1 cell, RAW264.7 cell and HepG2 cell. Conclusion : Development of RG with superior lineage suitable for changing climate is required. We selected a good lineage (21 ea), and result of the cytotoxicity evaluation from low to high concentrations in immune- and liver-derived cells, there was no toxicity at all. Therefore, if these excellent lineages are distributed to farmers, they can help farmers. And it can help research on immunity and liver function in the future.

Background : Rehmannia glutinosa is a perennial herb belonging to family Scrophulariaceae. This study was breeding of R. glutinosa cultivar with insect tolerance and high-yielding. Methods and Results : ‘Chunggang’ is developed by the medicinal crop breeding team of National Institute of Horticulture and Herbal Science (NIHHS), Rural Development Administration (RDA), during the period from 2005 to 2017. The reproduction of Rehmannia glutinosa has been accomplished mainly by vegetative propagation with its seedlings. This cultivar was selected from seedling of RG10. The plant type of Chungang is some rising from ground. Regional yield trials conducted at three site from 2016 to 2017. The root yield of ‘Chunggang’ was 22.3 ton per hectare, which was increased 11% compared with ‘Jihwang 1’ (check variety). Also, ‘Chunggang’ has higher insect tolerance compared with ‘Jihwang 1’. Conclusion : ‘Chunggang’ is a insect tolerance and high-yielding Rehmannia glutinosa cultivar.

Background : The cultivation area of Rehmannia glutinosa Liboschitz is 156 ㏊ ('16), which is one of my representative medicinal crops. However, since it grows by roots, the damage of the repeated cultivation and the degeneration of the seedstock are increasing. To solve these problems, we are developing new varieties every year by testing the regional adaptability of high quality system. In recent years, as the quality and quantity of new varieties have been proven to increase, the need for continuous development of excellent varieties is increasing. Methods and Results : The test material used a jihwang-1 as standard variety, the system was planted in 3-year (RGES 20), 2-year (RGES 21, 22, 23) and 3-year (RGES 24, 25). The root lengths were cut at intervals of about 2 to 3 ㎝ and immersed for 20 minutes in a fludioxonil suspension concentrate (1,000-fold dilution) and shaded for 1 day. Sowing was planted on April 30th, and planting interval was 30 ㎝ × 15 ㎝. Growth investigation was carried out on the overground growing (plant length, leaf length, leaf number, plant type, etc) and degree of generation of pests. As a result of the growth investigation, the third year RGES 20, the second year RGES 22, and the first year RGES 25 were excellent. RGES 20 was upright type and superior in overground growing, RGES 22 had strong pest resistance. RGES 25 was characterized by strong at high temperature, but growth is not as good as other high quality system. Conclusion : Recently, the difficulty of cultivation of zucchini has been increasing due to abnormal weather. Especially in this year, high temperature of 35℃ or more continued for about 30 days, and the need to cultivate varieties resistant to high temperatures is increasing. Therefore, it is expected that RGES 25 can be registered as a promising strain that is resistant to high temperature if the yield is corrected.

Background : Rehmannia glutinosa L. that is a perennial plant belonging to the family Scrophulariaceae is one of the most popular local income crops. Recently, the cultivation area of Chungnam (2017) accounts for 50.5% (106 ha) of the whole country. In July and August, which is the off-season at the highest price of R, glutinosa L. This experiment was carried out to develop early harvest cultivation technology for the improve farm income. Methods and Results : In order to investigate the growth characteristic and yield of R, glutinosa L. by using the rhizome of 'Tokang' were transplanted four times at intervals of 10 days from mid-March to mid-April 2017 and 2018. Growth characteristics of the above and under ground part were investigated by 3 repetitions for 10 ea harvested in mid-July. Regression analysis was performed on the relationship between the planting time and fresh root weight. The highest emergence rate was 88.7% in the mid-March, and the highest above ground part growth was observed in the plant height, leaf number, leaf length, leaf width, and fresh leaves weight. The number of days to flowering tended to be shortened to 60, 53, 52, and 49 days from the mid-March to the mid-April. The growth of underground part was also highest in mid-March and the total root weight per 10 a was also 1,127.4 ㎏ in mid-March. The faster the planting time, the higher the yield. The results of the linear regression on the roots weight according to the planting time showed that there was a negative correlation relation between the planting time, the marketable roots weight, rhizome weight and total roots weight. Conclusion : The total roots weight improved by 80% in the mid-March than mid-April. Therefore, mid-March is considered optimal planting time for off-season production of R. glutinosa L.

Background : Rehmannia glutinosa is a perennial herb belonging to family Scrophulariaceae. This study was conducted to evaluate the appropriateness through seedling cultivation of R. glutinosa. Methods and Results : The root of R. glutinosa cultivar (Jihwang 1) was harvested in the middle of March. Seed rhizomes were seedling after air curing for three days. And seed rhizomes were plug seedlings for 30 days (30D), 45 days (45D) and 60 days (60D) then planted in the test field. Mat formation rate in 30D, 45D and 60D was 81.3, 100 and 100% respectively. Flowering occurred only in 45D and 60D except 30D. Flowering rate of 45D and 60D were 7.3 ± 3.06 and 13.3 ± 1.15%. Agronomic characteristics were evaluated in comparison with ND (directly seeded group). As a results, aerial parts of 30D in plant height, leaf length and leaf width were better than other treatment group but the number of leaf per plant was statistically the same. Also, root shape was similar when comparing ND and seedling groups. Conclusion : Taken together, it is thought that the cultivation of R. glutinosa. seedlings is possible. However, further evaluation of the economic aspect is needed.

The use of Rehmannia glutinosa of the family Scrophulariaceae, in traditional medicine is well known. This study was conducted to elucidate the effect of air curing of the seed rhizome of R. glutinosa on its storability and yield. Methods and Results: The root of the R. glutinosa cultivar (Dagang) was harvested in at the end of November. The seed rhizomes were air cured for one to seven days. They were subsequently wrapped with newspaper and further stored in a plastic container at 1℃. It was observed that the weight loss and decay rates were significantly lower in the air cured seeds than in the untreated ones. Moreover, the decay rate of the control was approximately 50%, 120 days after storage. However. the decay rate of all the air cured treatment groups was less than 1%. Additionally, air curing led to an increase in the germination rate of the seeds and the root yield when compared with the untreated groups. Taken together, the ideal treatment period for air curing was found to be 3 days. Under these conditions, the germination rate and yield were 88.7% and 2,185 ㎏/10a, respectively. Conclusions: This study successfully demonstrated that the air curing of seed rhizomes can lead to a considerable increase in the storability and yield of R. glutinosa.

Background : Rehmannia glutinosa Libosch. is a perennial herb belonging to family Scrophulariaceae. It is also considered as a valuable medicinal plant in Asia including Korea, China and Japan because of its anti-anemic, anti-pyretic, anti-inflammatory and anti-senescence effects. Unfortunately it is difficult to propagate seeds due to poor seed viability and low propagation rate. Therefore, this plant is propagated vegetatively, but its vegetative propagation increases the incidence of virus infections in commercial fields, which can induce the production loss critically. So we have tried to compare the efficacy of virus elimination from R. glutinosa by thermotherapy, chemotherapy and shoot tip culture to find an optimal micropropagation for healthy and virus-free plant production. Methods and Results : For virus elimination, thermotherapy (heat treatment at 37℃ for 4 weeks), chemotherapy (addition into medium with antiviral agent) and shoot tip culture (meristem culture) were accomplished. After treatments, RT-PCR and ELISA methods were used for detection of three viruses including tobacco mosaic virus (TMV), cucumber mosaic virus (CMV), broad bean wilt virus (BBWV). Conclusion : Efficiency of virus elimination was enhanced up to 59% in shoot tip culture, however, lowest at 5 - 10% after chemotherapy using antiviral agent (ribavirin). Most samples were verified to have multiple virus infection. From these results, we can suggest that combination treatment of shoot tip culture and thermotherapy may be more effective for the elimination of major viruses from R. glutinosa.

Background : Rehmannia glutinosa root (R. root) has been used as traditional medicine, and is important resource for natural medicines and functional foods. In Korea, various varieties of Rehmannia glutinosa have been developed, and these have various characteristics depending on the variety. Therefore, this study was performed to compare the antioxidant and anti-aging activities of R. root extracts with various varieties (Jihwang 1ho, Goryeo, Daegyeong, Gogang, Togang, Dagang, Wongang, Yeongang, Hwanggang, and Segang). Methods and Results : R. roots were extracted by reflux extraction method with 70% ethanol-water solution at 40℃, and their extracts were used for total phenolic contents, antioxidant and anti-aging activities. The total phenolic content, ABTS and DPPH radical scavenging activities were highest in Yeongang, and these values were 11.50 ㎎/g, 9.37 ㎍/g TEAC, and 7.13 ㎍/g TEAC, respectively. However, the anti-aging activity on human dermal fibroblast cells treated with doxorubicin was higher in Segang, Dagang, and Goryeo than other varieties, and their senescence ratios were measured at 50.66, 57.16, and 61.36% when treated at 200 ㎍/㎖, respectively. The total phenolic content and DPPH radical scavenging activity were negatively correlated with anti-aging activity. Conclusion : These results indicated that the antioxidant and anti-aging activities of R. root extracts were differed according to variety of Rehmannia glutinosa, and positive correlation between anti-oxidant activities and anti-aging activity was not shown.

Background : Rehmannia glutinosa root (R. root) has been used as traditional medicine, and is important resource for natural medicines and functional foods. However, R. root have catalpol which have bitterness, and undigested sugars, including stachyose, raffinose, and verbascose as main compounds, and these compounds can cause diarrhea and abdominal pain. Therefore, this study was performed to determine the changes in reducing sugar producted from undigested sugars and catalpol contents as a bitter taste compound in R. root with aging treatment conditions. Methods and Results : R. root was treated at 10 - 70℃ for 0 - 48 h, and extracted with 50% ethanol solution. Their catalpol content was analyzed using HPLC-UVD, reducing sugar content generated from undigested sugars was measured by the Nelson-Somogyi methods, and these reaction rates were calculated from their variation according to aging time and temperature. During aging treatment, reducing sugar content increased and catalpol content decreased. Their formation and degradation rates were highest at 50℃ and 30 - 40℃, and their rates were 1.89 ㎎/g·h and 23.09 - 23.33%/h, respectively. Conclusion : These results indicated that aging treatment can positively affect the sweetness and digestibility of R. root slurry. Therefore, aging treatment could be considered for improving the sensory qualities and digestibility of R. root.