• Korean Journal of Plant Taxonomy
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• v.38 no.3
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• pp.233-250
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• 2008

Morphological and molecular data from the nuclear ribosomal ITS regions were examined to reevaluate the taxonomic position of the Korean endemic species, Stewartia koreana Nakai ex Rehder (Theaceae). Comparing to its morphologically closely related S. pseudocamellia Maxim, S. koreana has diagnostic characters including a larger leaf blade (10 cm length and 5.5 cm wide) and a longer pedicel (2.5 cm length). In addition, S. koreana formed a different clade from S. pseudocamellia in the ITS trees. The morphological and ITS sequence data supported S. koreana as a Korean endemic species distinct from the closely related species, S. pseudocamellia.

• Journal of Korean Society of Forest Science
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• v.97 no.3
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• pp.296-304
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• 2008

This study was carried out to analyze vegetation and soil characteristic, and ordination of Stewartia koreana community. The Stewartia koreana community was classified into Acer mono subcommunity, Pinus densiflora subcommunity, Sapium japonicum subcommunity, and Stewartia koreana typical subcommunity. In the study sites, soil organic matter, nitrogen, available phosphorous, exchangeable K, exchangeable Ca, exchangeable Mg concentration, cation exchange capacity, and soil pH were ranged from 14.31~34.27%, 0.33~0.77%, 7.83~22.88(mg/kg), 0.23~1.07(me/100 g), 0.29~2.93(me/100 g), 0.33~1.49(me/100 g), 10.47~22.48(me/100 g), and 4.65~4.96, respectively. The area of the Acer mono subcommunity, found in highlands, showed that contained the highest organic substances, nitrogen, available phosphorous, and cation exchangeable capacity concentration among the communities. The low elevation regions where the Pinus densiflor subcommunity is formed, showed the lowest concentrations of exchangeable Ca, and Mg.

• Korean Journal of Agricultural Science
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• v.8 no.1
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• pp.11-17
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• 1981

The study was carried out to investigate the distribution and composition of community of Stewartia koreana in Temple Huibang and Mt. Sogri. The results obtained were as follows: 1. Within the forest floor cover species of the Temple Huibang forest, higher importance value were observed as Calamagrostis arundinacea. Sasa borealis. Lindera erythrocarpa and Lindera obtusiloba 2. In the forest floor cover species of Mt. Sogri forest, higher importance value were observed as Sasa borealis and Acer pseudo-sieboldianum var. koreanum 3. Within the floor cover species under Stewartia koreana forest, higher importance value were observed as Sasa borealis. Acer pseudo- sieboldianum var. koreanum and Calamagrostis arundinacea 4. Under shrub layer of Stewartia koreana stands, 73% of Sasa borealis and Calamagrostis arundinacea in Temple Huibang and 93% of Sasa borealis in Mt. Sogri were counted respectively as dominant species. Therefore, it might be necessary to control such dominant undergrowing species for natural reproduction of Stewartia koreana 5. In the Temple Huibang sites, by 700m Sasa borealis and 800m Calamagrostis arundinacea were grown as dominant species.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.436-446
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• 2023

Since Stewartia koreana leaves are registered with the Food and Drug Administration as edible herbal materials, they are used in the development of functional foods, cosmetics, and medicines. In this study, we established an analysis method that can simultaneously analyze two indicators, hyperoside (quercetin 3-O-galactoside) and isoquercitrin (quercetin 3-O-glucoside) contained in the leaves of S. koreana using HPLC-DAD. In accordance with the Ministry of Food and Drug Safety's health functional food guidelines, the analysis method was verified for specificity, accuracy, precision, limit of quantification, and linearity. The analysis method established in this study showed more than 0.9989 of the correlation coefficient values (r²) for the calibration. The total recovery rates of isoquercitrin and hyperoside were 100.55 and 98.87% with 0.14-0.78 and 0.47-0.67% of the relative standard deviation, respectively. Therefore, it was suggested that the new analytical method would be applied to standardize raw materials and high value-added products originated from the leaves of the S. koreana in the future.

• Biomolecules & Therapeutics
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• v.18 no.2
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• pp.191-196
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• 2010

In the course of screening for antioxidant compounds by measuring the radical scavenging effect on 1,1-diphenyl- 2-picrylhydrazyl (DPPH), a total extract of the twigs of Stewartia koreana (Theaceae) was found to show potent antioxidant activity. Subsequent activity-guided fractionation of the methanolic extract led to the isolation of six phenolic compounds, ampelopsin (1), catechin (2), proanthocyanidin-A2 (3), fraxin (4), (2R, 3R)-taxifolin-3-${\beta}$-D-glucopyranoside (5), and (2S, 3S)-taxifolin-3-${\beta}$-D-glucopyranoside (6), as active principles. Their structures were elucidated by spectroscopic studies. Compounds 1-6 were isolated for the first time from this plant. Among them, three compounds 1-3 showed the significant antioxidative effects on DPPH, and riboflavin originated superoxide quenching activity. In riboflavin-nitrobluetetrazolium (NBT)-light system, compound 1 showed better superoxide quenching activity than vitamin C.

• Molecules and Cells
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• v.23 no.3
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• pp.398-404
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• 2007

Cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) are involved in various pathophysiological processes such as inflammation and carcinogenesis. In a search for inhibitors of COX-2 and iNOS production we found that extracts of Stewartia koreana strongly inhibited NO and $PGE_2$ production in LPS-treated macrophage RAW 264.7 cells. We have now shown that the mRNA and protein levels of iNOS and COX-2 are reduced by the Stewartia koreana extract (SKE). SKE inhibited expression of an NF-${\kappa}B$ reporter gene in response to LPS, and gel mobility shift assays revealed that SKE reduced NF-${\kappa}B$ DNA-binding activity. The extract also inhibited LPS-induced phosphorylation of $I{\kappa}B-{\alpha}$ and nuclear translocation of p65. Administration of the extract reduced the symptoms of arthritis in a collagen-induced arthritic mouse model. These results indicate that Stewartia extracts contain potentially useful agents for preventing and treating inflammatory diseases.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2001.06a
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• pp.85-88
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• 2001

차나무과에 속하는 노각나무(Stewartia Koreana)는 내음성이 강하고 공해에 잘견디는 수종으로서 6월말부터 8월에 걸쳐 흰색의 동백꽃 모양의 꽃이 피고, 수피의 모양이 모과나무의 수피와 비슷한 홍황색의 광택이 나는 비단과 같은 얼룩무늬 수피를 가지고 있어 멀리서 보아도 눈에 띄일 정도로 아름다운 모습을 지녔으며, 가을에는 단풍의 아름다움도 커 조경 및 원예적 가치가 높은 수종이다.(중략)

• Horticultural Science & Technology
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• v.29 no.2
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• pp.116-122
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• 2011

In this study, we report the generation and analysis of 1,392 expressed sequence tags (ESTs) from Korean Stewartia (Stewartia koreana Nakai). A cDNA library was generated from the young leaf tissue and a total of 1,392 cDNA were partially sequenced. EST and unigene sequence quality were determined by computational filtering, manual review, and BLAST analyses. Finally, 1,301 ESTs were acquired after the removal of the vector sequence and filtering over a minimum length 100 nucleotides. A total of 893 unigene, consisting of 150 contigs and 743 singletons, was identified after assembling. Also, we identified 95 new microsatellite-containing sequences from the unigenes and classified the structure according to their repeat unit. According to homology search with BLASTX against the NCBI database, 65% of ESTs were homologous with known function and 11.6% of ESTs were matched with putative or unknown function. The remaining 23.2% of ESTs showed no significant similarity to any protein sequences found in the public database. Annotation based searches against multiple databases including wine grape and populus sequences helped to identify putative functions of ESTs and unigenes. Gene ontology (GO) classification showed that the most abundant GO terms were transport, nucleotide binding, plastid, in terms biological process, molecular function and cellular component, respectively. The sequence data will be used to characterize potential roles of new genes in Stewartia and provided for the useful tools as a genetic resource.

• Korean Journal of Pharmacognosy
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• v.42 no.3
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• pp.229-232
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• 2011

Three dihydrochalcone compounds were isolated from the twigs of Stewartia koreana (Theaceae) through repeated column chromatography. Their chemical structures were elucidated as phloridizin, 2',4,4'-trihydroxy-6'-methoxydihydrochalcone and confusoside, respectively, by spectroscopic analysis. These compounds were isolated for the first time from this plant.

• Korean Journal of Environment and Ecology
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• v.25 no.5
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• pp.725-735
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• 2011

This study was carried out to analyze the vegetation properties, soil characteristics, and ordination of Stewartia koreana community of Mt. Jirisan in Korea. The S. koreana community was classified into S. koreana-Quercus mongolica serrata community, S. koreana-Quercus mongolica community, and Typical community. In specific, S. koreana-Q. serrata community was classified into two subgroups such as Carpinus laxiflora subcommunity and typical subcommunity. The S. koreana community was found out to be located at an elevation of 409m to 1,604m. The Results of importance value on the S. koreana community consisted of the following in order: 75.47% of S. koreana, the highest, 21.83% of Q. serrata, 18.65% of Q. mongolica, 18.19% of Acer pseudosieboldianum, 10.56% of Rhododendron schlippenbachii, 10.36% of Styrax japonicus. In the targeted study sites, soil organic matter, total nitrogen, available phosphate, exchangeable potassium, soil moisture and soil pH were 3.15~39.1%, 0.37~11.7%, 0.9~45.4mg/kg, $0.09{\sim}1.48cmol^+/kg$, 19.28~55.47% and 4.08~5.65, respectively. The results of the correlation between communities and soil conditions of S. koreana community by DCCA ordination method are as follows: S. koreana-Q. serrata community was found in the highest elevation and followed in order S. koreana typical community, S. koreana-Q. serrata typical subcommunity, and C. laxiflora subcommunity.