• Journal of Life Science
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• v.31 no.4
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• pp.377-384
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• 2021

Researching the soil fungal community is important to understand the interaction between fungi and living plants. However, too few studies have examined the soil fungal community and their interactions with plants. Rhododendron mucronulatum, commonly known as Korean rosebay, is an important forest resource that has aesthetic, ecological, and potential pharmacological values. We used a pyrosequencing method to analyze the characteristics of fungal communities from R. mucronulatum soil samples from Biseul mountain county park, which is one of the famous places for large R. mucronulatum colonies in South Korea. We collected soil core samples in February and August at three sites in the Biseul Mountain County Park, taking into consideration the regional and seasonal conditions. We obtained 454,157 validated reads after pyrosequencing all six samples. The fungal communities from the first observation spot in August had the richest species diversity among the samples. Basidiomycota, Ascomycota, and Mortierellomycota were major phyla in the samples. Agaricales_f, Mortierellaceae, and Clavariaceae were major families in the samples. The genus Mortierella was the most dominant in all six samples. Overall, 19 genera could be associated with R. mucronulatum. Sample 1 had 109 genera in sample 1, sample 2 had 111 genera, and sample 3 had 112 genera that were uniquely identified. The samples collected in August had 28 identified genera, that existed only in summer samples, indicating a weather effect. This study can be used as basic research to understand the relationship between soil fungi and plants.

• Korean Journal of Agricultural Science
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• v.39 no.1
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• pp.69-73
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• 2012

The purpose of this study was to evaluate the potential of naturally occurring aldose reductase (AR) inhibitors from white-color natural products (Aruncus dioicus var. kamtschaticus, Chionanthus retusa, Cosmos bipinnatus, Hibiscus syriacus, Hydrangea paniculata, Magnolia denudata, Prunus padus, Robinia pseudo-accacia, Rhododendron mucronulatum for. albiflorum, Spiraea blumei, and Spiraea prunifolia var. simpliciflora). The MeOH extract of white-color natural products were tested on rat lens AR inhibition in vitro. Among them, the MeOH extract of R. mucronulatum for. albiflorum showed highest inhibition on AR ($IC_{50}$ value, 1.07 ${\mu}g/ml$). These results suggested that R. mucronulatum for. albiflorum, a white-color natural product, could be a useful resource in the development of a novel AR inhibitory agent against diabetic complications.

• The Korean Journal of Mycology
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• v.45 no.2
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• pp.102-106
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• 2017

A fungal strain was isolated from surface-sterilized roots of Rhododendron mucronulatum, a plant species belonging to the Ericaceae family, collected from Mt. Minjujisan, Korea. This fungal strain was identified as Rhizodermea veluwensis based on its morphological characteristics and based on phylogenetic analysis of its internal transcribed spacer regions and large-subunit rDNA. R. veluwensis has not been previously reported in Korea, and for the first time, we report and describe it herein.

• Horticultural Science & Technology
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• v.16 no.1
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• pp.33-36
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• 1998

This study was carried out to examine the effects of cutting dates and rooting promoters on rooting of the Rhododendron mucronulatum Turcz. The rooting percentage in greenwood cutting was high in June and decreased after July 3, when reproductive growth began. The best rooting percentage(92.5%) occurred when cutting was completed on June 12. There was no difference in rooting potentials between the greenwood straight cutting and the greenwood heel cutting. Cuttings of R. mucronulatum for. albiflora showed high rooting percentage(85%) similar to the cuttings of R. mucronulatum. Dipping cuttings in NAA $2,000mg{\cdot}L^{-1}$ solution for 15 sec increased the rooting percentage up to 97.5%, and also promoted root growth.

• Food Science and Preservation
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• v.13 no.4
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• pp.501-505
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• 2006

This study was carried out to investigate the antioxidative activity and cytotoxicity on human KB cell of extract from Rhododendron mucronulatum flower, and also to determine the contents of total polyphenol and flavonoid. The methanol extract of Rhododendron mucronulatum flower was fractionated with various solvents such as hexane, chloroform, ethyl acetate, butanol and water. The DPPH radical scavenging activities of ethyl acetate fraction had stronger activity than other fractions. So, antioxidative substances of ethyl acetate fraction were crude purified by silica gel column chromatography. The DPPH radical scavenging activities of crude purified fraction 2 and 3 were more than 90% at 40 ppm. In the presence of $100{\mu}g/mL$, growth inhibition on human KB cell by WST-1 assay showed 81.2% in chloroform fraction and 74.6% in hexane fraction. The contents of total polyphenol and flavonoid of ethyl acetate traction were 32.70% and 20.30%, respectively, The antioxidative activity showed correlation with total polyphenol and flavonoid contents.

• Journal of the Korean Institute of Landscape Architecture
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• v.18 no.4
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• pp.73-85
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• 1991

Rhododendron mucronulatum for. albiflorum, native species is a shrub that has white flowers on May to June, and rare species endangered by people's rash digging or cutting. But its physiological ecological characteristics and propagation method are not being known at all. Therefore, this study was executed to utilize this species as the planting material for landscaping by analysing its habitat environment and growth form, and also experimenting its seed and vegetative propagation, and it field culture and utilization. The results are as follows; 1. The elevation, gradient and direction of this species were 295-1,350m, 10-36$^{\circ}$, northwest respectively. It was found that the species is shade-liking plant that grows under forest cover of average 51.33%. 2. The soil pH and water content of its habitat were 5.4, 25.41% respectively. The organic matter content was 6.29% that was higher than 3.2%, the average organic matter content of forest soil in Korea. 3. Representative plant community within which this species was living was Quercus mongolica community, and its main neighboring species were Lindea obtusiloba, Fraxinus sieboldiana, Rhus trichocarpa, Rhododendron Schlippenbachii, Rododendron mucronulatum. 4. The leaf length and width of this species were 39.18mm, 12.60mm respectively. This result showed that generally its leaf size was larger than that of R. micranthum, R. yedoense var. poukhanense and R. mucronulatum var. ciliatum and smaller than that of R. mucronulatum and R. schlippenbachii. 5. The whole size of its pollen was, as 59${\times}$61$\mu\textrm{m}$, the largest of plants of Rhododendron family including R. mucronulatum and R. mucronulatum var. ciliatum. 6. The result of seed germination experiment at intervals of 5$^{\circ}C$ from 15$^{\circ}C$ to 30$^{\circ}C$ presented the highest germination rate of 94.7% at 20$^{\circ}C$ numerically, but high percent germination at all temperature levels without significant difference. And the seed of this plant proved to be sun-liking seed at requiring dormancy in germination. 7. Through seed germination experiment by treatment of growth regulators such as GA. Thiourea and Kinetin under dark condition, it was found that the effect of GA treatment on germination increase and acceleration was the highest. 8. In greenwood cutting, rooted rate by treatment of various concentration of IBA and NAA on clay and vermiculite bed was not wholly high, but 100ppm plots of both IBA and NAA of clay bed showed relatively good rooted rate. 9. As result of field culture experiment for finding out optimum growth temperature and light intensity, growth conditions such as height, number of leaves, fresh weight and chlorophyll contents were the best at night/day temperature of 20/25$^{\circ}C$ and under 1/2sun. Also, the photosynthetic rate was the highest at 25$^{\circ}C$. Accordingly, it was found that optimum temperature and light intensity for growth of this plant are 25$^{\circ}C$ (day temperature), 50% of natural light respectively.

• The Journal of Internal Korean Medicine
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• v.43 no.1
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• pp.68-78
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• 2022

Objective: In this study, we investigated the protective effect of rhododendron mucronulatum extract (RME) on allergic reactions and inflammation. Methods: The effect of RME was determined using ELISA and RT-PCR in RBL-2H3 mast cells and RAW 264.7 macrophage cells. We determined cell viability, β-hexosaminidase release, and the synthesis of IL-4 and TNF-α in RBL-2H3 cells. In addition, we determined NO from RAW 264.7 and the gene expression of IL-1β, iNOS, IL-6, TNF-α, and IL-10. Results: RME inhibited β-hexosaminidase release and synthesis of IL-4 and TNF-α in RBL-2H3 by the anti-DNP IgE plus DNP-HSA stimulation. In addition, RME inhibited the production of NO and the gene expression of IL-1β, iNOS, IL-6, and TNF-α in LPS-stimulated RAW 264.7 cells. Conclusion: From these results, we concluded that RME possesses anti-allergic activity and anti-inflammatory activity due to the inhibition of mast cells and macrophage function.

• Korean Journal of Environment and Ecology
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• v.24 no.2
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• pp.194-201
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• 2010

This study was carried out to analyze vegetation and soil characteristic, and ordination of subalpine forest vegetation of Daecheongbong area, Mt. Seorak. Communities by characteristic in species composition of subalpine forest were classified into Rhododendron mucronulatum var. ciliatum - Betula ermani community group, Pinus pumila, Abies nephrolepis, Thuja koraiensis, and Rhododendron mucronulatum var. ciliatum - Betula ermanii typical community. The results of the correlation between forest communitie sand soil conditions of Daecheongbong area by DCCA ordination method are as follows: The Pinus pumila community and Thuja koraiensis community were mainly found in the high percentage area of total nitrogen, available phosphorous, organic matter in comparison with Abies nephrolepis community and Rhododendron mucronulatum var. ciliatum - Betula ermanii typical community. The Abies nephrolepis community and Rhododendron mucronulatum var. ciliatum - Betula ermanii typical community were mainly found in the high elevation area in comparison with Pinus pumila community and Thuja koraiensis community. The Pinus pumila community and Thuja koraiensis community were mainly found in the northern and northwestern direction, but Abies nephrolepis community and Rhododendron mucronulatum var. ciliatum - Betula ermanii typical community were mainly found in the southwestern direction.

• Journal of Life Science
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• v.26 no.11
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• pp.1245-1252
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• 2016

As a research of inflammation inhibitory activity using natural resource, the inflammation inhibitory activity by purified active compound from Rhododendron mucronulatum flower was experimented. Rhododendron mucronulatum flower components were purified and separated with Sephadex LH-20 and MCI gel CHP-20 column chromatography, Purified compound was confirmed as myricetin by $^1H-NMR$, $^{13}C-NMR$ and Fast atom bombardment (FAB)-Mass spectrum to have inhibition activity on inflammatory factors secreted by Raw 264.7 cells in response to lipopolysaccharide stimulation. Myricetin inhibited nitric oxide (NO) expression in a concentration dependent manner, approximately 40% inhibition was observed at a concentration of $50{\mu}M$. The inhibition effect of myricetin on inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 protein expression was 20% and 80%, respectively, at a concentration of $25{\mu}M$. Myricetin also inhibited expression of the inflammatory cytokines, tumor necrosis factor $(TNF)-{\alpha}$, interleukin $(IL)-1{\beta}$, IL-6 and prostaglandin $E_2(PGE_2)$ in a concentration dependent manner; a concentration of $50{\mu}M$, 70%, 80%, 80% and 95% inhibition was observed, respectively. Therefore myricetin isolated from Rhododendron mucronulatum flowers is expected to have an anti-inflammatory effect in Raw 264.7 cell induced by lipopolysaccharides. The results can be expected myricetin from Rhododendron mucronulatum flower to use as functional resource for anti-inflammatory activity.

• Journal of Life Science
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• v.19 no.8
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• pp.1125-1131
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• 2009

The antimicrobial activities of Helicobacter pylori as a functional food source with water and 60% ethanol extracts from Rododendron mucronulatum Turcz. flowers were examined. The total phenol content of 60% ethanol extracts (30.6${\pm}$0.14 mg/g) from Rododendron mucronulatum Turcz. flowers was higher than that of water extracts (23.2${\pm}$0.21 mg/g). The inhibitory activities of Rododendron mucronulatum Turcz. extracts on H. pylori was determined to clear zone of 15 mm in 80% ethanol extracts. Purification of inhibitory compounds was carried out in Sephadex LH-20 and MCI-gel CHP-20 column chromatography using a gradient procedure, with increasing ethanol(0${\rightarrow}$100%) in $H_2O$. The chemical structure of the purified inhibitory compounds of H. pylori was identified to be quercitrin (quercetin-3-O- rhamnopyranoside), myricitrin (myricetin-3-O-rhamnopyranoside), quercetin by FAB-MS, NMR and IR spectra.