Acer Okamotoanum Research Articles

Insect fauna of Seonginbong in Ulleungdo, Korea

Seonginbong primeval forest (984 m) located in the center of Ulleungdo, an island of Korea, is designated as forest genetic resource reserve by the Korea Forest Service, and as Natural Monument No. 189. Approximately 40 species of endemic plants that are native to Ulleungdo are found at Seonginbong. In addition, there are colonies of Fagus engleriana , Acer okamotoanum, and Tilia insularis , which are rare on the Korean Peninsula. The distribution of insects inhabiting plants is expected to differ when compared to the inland distribution, and therefore, this study investigated the insect fauna of Seonginbong on Ulleungdo by altitude. The survey was conducted four times in 2020 using four collection methods (light trap, pit-fall trap, molasses trap, and sweeping). Seonginbong was divided into lowland (300–500 m), midland (500–800 m), and highland (800–980 m) sections, and each section was subdivided into five collection points. A total of 11 orders and 113 families were collected. Further investigation with identification at the species level is required to determine the diversity of the insect fauna at Seonginbong.

Neuroprotective effects of three flavonoids from Acer okamotoanum against neurotoxicity induced by amyloid beta in SH-SY5Y cells

Neuroprotective effects of three flavonoids from Acer okamotoanum against neurotoxicity induced by amyloid beta in SH-SY5Y cells

The Protective Effects of Acer okamotoanum and Isoquercitrin on Obesity and Amyloidosis in a Mouse Model.

Obesity increases risk of Alzheimer’s Disease (AD). A high fat diet (HFD) can lead to amyloidosis and amyloid beta (Aβ) accumulation, which are hallmarks of AD. In this study, protective effects of the ethyl acetate fraction of Acer okamotoanum (EAO) and isoquercitrin were evaluated on obesity and amyloidosis in the HFD- and Aβ-induced mouse model. To induce obesity and AD by HFD and Aβ, mice were provided with HFD for 10 weeks and were intracerebroventricularly injected with Aβ25–35. For four weeks, 100 and 10 mg/kg/day of EAO and isoquercitrin, respectively, were administered orally. Administration of EAO and isoquercitrin significantly decreased body weight in HFD and Aβ-injected mice. Additionally, EAO- and isoquercitrin-administered groups attenuated abnormal adipokines release via a decrease in leptin and an increase in adiponectin levels compared with the control group. Furthermore, HFD and Aβ-injected mice had damaged liver tissues, but EAO- and isoquercitrin-administered groups attenuated liver damage. Moreover, administration of EAO and isoquercitrin groups down-regulated amyloidosis-related proteins in the brain such as β-secretase, presenilin (PS)-1 and PS-2 compared with HFD and Aβ-injected mice. This study indicated that EAO and isoquercitrin attenuated HFD and Aβ-induced obesity and amyloidosis, suggesting that they could be effective in preventing and treating both obesity and AD.

Flavonoids from Acer okamotoanum Inhibit Adipocyte Differentiation and Promote Lipolysis in the 3T3-L1 Cells.

Flavonoids, quercitrin, isoquercitrin (IQ), and afzelin, were isolated from ethyl acetate fraction of Acer okamotoanum. We investigated anti-obesity effects and mechanisms of three flavonoids from A. okamotoanum in the differentiated 3T3-L1 cells. The differentiated 3T3-L1 cells increased triglyceride (TG) contents, compared with non-differentiated normal group. However, treatments of three flavonoids from A. okamotoanum decreased TG contents without cytotoxicity. In addition, they showed significant down-regulation of several adipogenic transcription factors, such as γ-cytidine-cytidine-adenosine-adenosine-thymidine/enhancer binding protein -α, -β, and peroxisome proliferator-activated receptor-γ, compared with non-treated control group. Furthermore, treatment of the flavonoids inhibited expressions of lipogenesis-related proteins including fatty acid synthase, adipocyte protein 2, and glucose transporter 4. Moreover, IQ-treated group showed significant up-regulation of lipolysis-related proteins such as adipose triglyceride lipase and hormone-sensitive lipase. In addition, flavonoids significantly activated 5′-adenosine monophosphate-activated protein kinase (AMPK) compared to control group. In particular, IQ showed higher inhibition of TG accumulation by regulation of pathways related with both adipogenesis and lipolysis, than other flavonoids. The present results indicated that three flavonoids of A. okamotoanum showed anti-obesity activity by regulation of adipocyte differentiation, lipolysis, and AMPK signaling, suggesting as an anti-obesity functional agents.

Analysis of Sap Production and Composition of Acer okamotoanum from Artificial Stands in Different Tapping Time in Jin-ju Region in Korea

This study was conducted to analyze the sap flow and composition by tapping date in Acer akamotoanum from an artificial forest in the City of Jinju. The sap was collected from five saplings (diameter at breast height10-20 cm) in two phases with an interval of a month. During phase 1 (January 10, 2019 – February 9, 2019) with daily mean temperature of 1.16±2.15°C, 60.59 liters of sap was collected over 32 days. Phase 2 (February 12, 2019 – February 22, 2019) with daily mean temperature of 2.55±1.30°C yielded 13.38 liters of sap over 11 days, which was a reduction to 22% of the total sap flow in phase 1. The analysis of sugar composition in the collected sap from phase 1 and 2 showed that sucrose concentration was 2.5% at its highest during the earlier days of collection and decreased to 0.8% at the end. Glucose and fructose concentrations were measured near 0, and were lower than sucrose concentration. The most prominent inorganic elements in the collected sap were potassium (41.69 - 89.75 mg/kg), calcium (24.66 - 48.14 mg/kg) and magnesium (10.18 - 27.25 mg/kg). The contents of sucrose and inorganic components between the samples collected from phase 1 and 2 did not show significant differences. The sap flow amounts of A. okamotoanum from different tapping periods showed a notable variation, but there were no significant differences in the contents of sugar or inorganic elements.

Acer okamotoanum inhibits adipocyte differentiation by theregulation of adipogenesis and lipolysis in 3T3‑L1 cells.

Acer okamotoanum is reported to have various antioxidant, anti‑inflammatory and beneficial immune system effects. The anti‑adipocyte differentiation effects and mechanisms of the ethyl acetate (EtOAc) fraction of an A.okamotoanum extraction was investigated in 3T3‑L1 adipocyte cells. Treatment with differentiation inducers increased the level of triglycerides (TGs) in 3T3‑L1 adipocyte cells compared with an untreated control. However, the EtOAc fraction of A.okamotoanum significantly decreased TGs. Treatment with 1, 2.5 and 5µg/ml showed weak activity, but TG production was inhibited at 10µg/ml compared with the control. In addition, A.okamotoanum caused a significant downregulation of proteins related to adipogenesis, such as γ‑cytidine‑cytidine‑adenosine‑adenosine‑thymidine/enhancer binding protein‑α, ‑β and peroxisome proliferator‑activated receptor‑γ, compared with the untreated control. Furthermore, A.okamotoanum significantly upregulated lipolysis related protein, hormone‑sensitive lipase and the phosphorylation of adenosine monophosphate‑activated protein kinase (AMPK). Therefore, these results indicate that A.okamotoanum suppressed adipogenesis and increased lipolysis and the activation of AMPK, suggesting a protective role in adipocyte differentiation.

Attenuation of hydrogen peroxide-induced oxidative stress in SH-SY5Y cells by three flavonoids from Acer okamotoanum

The flavonoids quercitrin, isoquercitrin, and afzelin were isolated from the ethyl acetate fraction of Acer okamotoanum. The effectiveness of these flavonoids in protecting human cells was investigated using SH-SY5Y neuronal cells. Oxidative stress was induced by hydrogen peroxide (H2O2) and cells treated with flavonoids had an increased viability as compared with untreated cells. The flavonoid-treated cells showed significantly less reactive oxygen species production and lactase dehydrogenase release than the untreated cells. Especially, quercitrin and isoquercitrin showed the strongest protective effects against oxidative stress among several tested flavonoids as determined by the results for cell viability, reactive oxygen species (ROS) production, and lactate dehydrogenase release. Furthermore, we measured the expression of inflammation- and apoptosis-related proteins. These flavonoids attenuated inflammation by downregulating the expression of cyclooxygenase-2, inducible nitric oxide synthase, and apoptotic signaling via inhibiting caspase activation. The present results suggest that three flavonoids of A. okamotoanum protect against cellular oxidative stress possibly through regulating inflammation, apoptosis, and ROS-scavenging.

Acer okamotoanum Nakai Leaf Extract Inhibits Adipogenesis Via Suppressing Expression of PPAR γ and C/EBP α in 3T3-L1 Cells.

The genus Acer contains several species with various bioactivities including antioxidant, antitumor and anti-inflammatory properties. However, Acer okamotoanum Nakai, one species within this genus has not been fully studied yet. Therefore, in this study, we investigated the anti-adipogenic activities of leaf extract from A. okamotoanum Nakai (LEAO) on 3T3-L1 preadipocytes. Adipogenesis is one of the cell differentiation processes, which converts preadipocytes into mature adipocytes. Nowadays, inhibition of adipogenesis is considered as an effective strategy in the field of anti-obesity research. In this study, we observed that LEAO decreased the accumulation of lipid droplets during adipogenesis and down-regulated the expression of key adipogenic transcription factors such as peroxisome proliferator-activated receptor γ (PPAR γ) and CCAAT/enhancer binding protein α (C/EBP α). In addition, LEAO inactivated PI3K/Akt signaling and its downstream factors that promote adipogenesis by inducing the expression of PPAR γ. LEAO also activated β-catenin signaling, which prevents the adipogenic program by suppressing the expression of PPAR γ. Therefore, we found that treatment with LEAO is effective for attenuating adipogenesis in 3T3-L1 cells. Consequently, these findings suggest that LEAO has the potential to be used as a therapeutic agent for preventing obesity.

Acer okamotoanum protects SH-SY5Y neuronal cells against hydrogen peroxide-induced oxidative stress.

Oxidative stress by over-production of reactive oxygen species (ROS) in brain is widely known as a cause of neurodegenerative disease. We investigated protective effects of Acer okamotoanum against oxidative stress by hydrogen peroxide (H2O2) in SH-SY5Y neuronal cells. Acer okamotoanum reduced ROS production and lactate dehydrogenase release in H2O2-induced SH-SY5Y cells, resulting in elevation of cell viability. To elucidate protective mechanisms, we measured inflammation and apoptosis-associated protein expressions. Treatment with A. okamotoanum dose-dependently decreased pro-inflammatory proteins such as inducible nitric oxide synthase and cyclooxygenase-2. Treatment with A. okamotoanum showed down-regulation of pro-apoptosis genes such as cleaved caspase-3, cleaved caspase-9, and Bax, and up-regulation of anti-apoptosis protein including Bcl-2, in H2O2-induced SH-SY5Y cells. We demonstrated potential anti-inflammatory and anti-apoptotic effect of A. okamotoanum in H2O2-induced SH-SY5Y cells. These results suggest that A. okamotoanum may possess neuroprotective potential, but further study is necessary to elucidate its pharmacological effects in neurodegenerative diseases.

Determination of flavonoids in Acer okamotoanum and their aldose reductase inhibitory activities

Plants in the genus Acer include medicinal plants and deciduous tree species in which several bioactive compounds have been isolated. In this study, flavonoids were isolated from the aerial parts of Acer okamotoanum by open column chromatography and identified by spectroscopic analysis as afzelin, quercitrin, and isoquercitrin. Among these flavonoids, quercitrin and isoquercitrin exhibited potent aldose reductase inhibitory activity (IC50 value of 0.40 and 0.63 μM, respectively). Almost all studied tissues of Acer spp. contained high amounts of quercitrin. The leaf of A. mono had the highest amount of quercitrin (61.90 μg g−1). Our results demonstrated that Acer species contain high concentrations of flavonoids with promising aldose reductase inhibitory activity that could be utilized to develop novel therapeutics for diabetic disorders.

Paenibacillus aceris sp. nov., isolated from the rhizosphere of Acer okamotoanum, a plant native to Ulleungdo Island, Republic of Korea.

Strain KUDC4121T was isolated from the rhizosphere of Acer okamotoanum, a plant native to the Korean island of Ulleungdo. The strain was a Gram-stain-positive, non-spore-forming, non-motile, rod-shaped bacterium that can grow at 18-37 °C and pH 6.0-7.5, with optimum growth at 30 °C and pH 7.0. It grew on tryptic soy agar containing less than 0.5 % (w/v) NaCl and in R2A broth. Cell length ranged from 2.0 to 2.5 µm. Strain KUDC4121T was oxidase- and catalase-positive and did not hydrolyse starch or casein. The genomic G+C content was 48.8 mol%. The major fatty acids were anteiso-C15 : 0 and iso-C16 : 0. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain KUDC4121T belongs to the genus Paenibacillus. The closest type strain was Paenibacillus chondroitinus DSM 5051T, with 97.8 % similarity, followed by Paenibacillus alginolyticus DSM 5050T (97.6 %), Paenibacillus ferrarius CY1T (97.5 %), Paenibacillus pocheonensis Gsoil 1138T (97.5 %), Paenibacillus frigoriresistens YIM 016T (97.5 %), Paenibacillus pectinilyticus RCB-08T (97.2 %) and Paenibacillus aestuarii CJ25T (96.9 %). Based on its phenotypic properties and phylogenetic and genetic data, strain KUDC4121T should be considered to represent a novel species of the genus Paenibacillus, for which the name Paenibacillus aceris sp. nov. is proposed. The type strain is KUDC4121T (=KCTC 13870T=DSM 24950T).

Acer okamotoanum improves cognition and memory function in Aβ25–35-induced Alzheimer’s mice model

We studied the effect of ethyl acetate (EA) fraction from Acer okamotoanum on cognitive improvement and protective abilities in amyloid beta (Aβ)25–35 peptide-injected Alzheimer’s disease (AD) mice. EA was oral administration at 100 and 200 mg/kg/day during the 14 days. We studied the protective effect of EA against AD on the basis of behavioral tests including T-maze test, Novel object recognition test, and Morris water maze test. Control group injected with Aβ25–35 showed significant impairments in memory function. But the oral administration of EA (EA 100 and EA 200 groups) improved the cognition and memory function. In addition, EA against Aβ25–35 peptide has been shown to inhibit lipid peroxidation levels and nitric oxide production in tissues. Acetylcholinesterase (AChE) was elevated in the brain by Aβ25–35 peptide, whereas administration of EA (EA 100 and EA 200 groups) significantly decreased AChE level. Our results indicated that EA improves learning and long-term memory against Aβ25–35 peptide–caused deficit through attenuation of oxidative stress.

Effects of Acer okamotoanum sap on the function of polymorphonuclear neutrophilic leukocytes in vitro and in vivo

Sap is a plant fluid that primarily consists of water and small amounts of mineral elements, sugars, hormones and other nutrients. Acer mono (A. mono) is an endemic Korean mono maple which was recently suggested to have health benefits due to its abundant calcium and magnesium ion content. In the present study, we examined the effects of sap from Acer okamotoanum (A. okamotoanum) on the phagocytic response of mouse neutrophils in vivo and rat and canine neutrophils in vitro. We tested the regulation of phagocytic activity, oxidative burst activity (OBA) and the levels of filamentous polymeric actin (F-actin) in the absence and presence of dexamethasone (DEX) in vitro and in vivo. Our results showed that DEX primarily reduced OBA in the mouse neutrophils, and that this was reversed in the presence of the sap. By contrast, the phagocytic activity of the mouse cells was not regulated by either DEX or the sap. Rat and canine polymorphonuclear neutrophilic leukocytes (PMNs) responded in vitro to the sap in a similar manner by increasing OBA. However, regulation of phagocytic activity by the sap was different between the species. In canine PMNs, phagocytic activity was enhanced by the sap at a high dose, while it did not significantly modulate this activity in rat PMNs. These findings suggest that the sap of A. okamotoanum stimulates neutrophil activity in the mouse, rat and canine by increasing OBA in vivo and in vitro, and thus may have a potential antimicrobial effect in the PMNs of patients with infections.

Genetic consequences of anagenetic speciation in Acer okamotoanum (Sapindaceae) on Ullung Island, Korea

Anagenesis (also known as phyletic speciation) is an important process of speciation in endemic species of oceanic islands. We investigated genetic variation in Acer okamotoanum, an anagenetically derived species endemic to Ullung Island, South Korea, to infer genetic consequences of anagenesis in comparison with other groups that have undergone cladogenesis (and adaptive radiation). We examined genetic variation based on eight polymorphic microsatellite markers from 145 individuals of A. okamotoanum and 134 individuals of its putative progenitor A. mono. We employed standard population genetic analyses, clustering analyses, Bayesian clustering analyses in STRUCTURE and bottleneck analyses. Based on both the Neighbor-Joining tree and Bayesian clustering analyses, clear genetic distinctions were found between the two species. Genetic diversity in terms of allelic richness and heterozygosity shows slightly lower levels in A. okamotoanum in comparison with A. mono. Bayesian clustering analyses showed a relatively high F-value in the cluster of A. okamotoanum, suggesting a strong episode of genetic drift during colonization and speciation. There was no clear evidence of a bottleneck based on allelic frequency distribution and excess of observed heterozygotes, but the M-ratio indicated a historical bottleneck in several populations of A. okamotoanum. No geographical genetic structure within the island was found, and the genetic variation among populations of A. okamotoanum was quite low. We hypothesized that genetic consequences of oceanic-endemic plants derived via anagenesis would be quite different from those derived via cladogenesis. Populations of A. okamotoanum form a cluster and are clearly differentiated from A. mono, which suggests a single origin for the anagenetically derived island endemic. No pattern of geographical differentiation of populations occurs in A. okamotoanum, which supports the concept of initial founder populations diverging through time by accumulation of mutations in a relatively uniform environment without further specific differentiation.

Beneficial effects of Acer okamotoanum sap on L-NAME-induced hypertension-like symptoms in a rat model

The sap of Acer okamotoanum has been termed 'bone-benefit-water' in Korea owing to its mineral and sugar content. In particular, the calcium (Ca) and potassium (K) concentrations of the sap of Acer okamotoanum are 40- and 20-times higher, respectively, than commercial spring water. In the present study, we examined whether Acer okamotoanum sap improves or prevents hypertension-like symptoms in a rat model. Male Sprague-Dawley rats (8-weeks-old) were provided commercial spring water supplemented with 25, 50 or 100% Acer okamotoanum sap, 3% potassium ions (K+) or captopril, and treated daily for 2 weeks with NG-nitro-L-arginine methyl ester (L-NAME; 100 mg/kg/day) by subcutaneous injection, in order to induce hypertensive symptoms. Rats were euthanized 6 h following the final injection. To assess the effect of the sap on hypertension-like symptoms, we examined the mean blood pressure (BP), protein levels and localization of endothelial nitric oxide synthase (eNOS) in the descending aorta of the rats. BP levels were significantly lower in hypertensive rats received 25, 50 and 100% sap compared with rats who were administered only commercial spring water. Protein levels of eNOS were repressed in L-NAME-only-treated rats, but were elevated in the descending aorta of rats administered captopril, K+ water and Acer okamotoanum sap (25, 50 and 100%) up to the level of the sham group provided commercial spring water, and then injected with dimethyl sulfoxide for the same period of time. Localized eNOS protein was abundantly expressed in the perivascular descending aorta adipose tissue of the rats. Taken together, these results demonstrated that the sap of Acer okamotoanum ameliorated high BP induced by L-NAME treatment in a rat model.

The sap of Acer okamotoanum decreases serum alcohol levels after acute ethanol ingestion in rats

In the present study, we examined whether Acer okamotoanum (A. okamotoanum) sap decreased the serum alcohol and acetaldehyde levels after acute ethanol treatment in a rat model. Male rats were orally administered 25, 50 or 100% A. okamotoanum sap 30 min prior to oral challenge with 3 ml of ethanol (15 ml/kg of a 20% ethanol solution in water), and the blood concentrations of alcohol and acetaldehyde were analyzed up to 7 h after the treatment. Pre-treatment with the sap significantly decreased the blood ethanol and acetaldehyde concentrations after 5 h when compared with ethanol treatment alone (a negative control). The expression levels of liver alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) mRNA were increased significantly in animals pre-treated with A. okamotoanum sap when compared with negative and positive controls. The data suggest that sap pre-treatment enhanced the alcohol metabolism rate in the rat liver. To investigate the involvement of mitochondrial regulation in the ethanol-induced hepatocyte apoptosis, we carried out an immunohistochemical analysis of Bax and Bcl-2. Pre-treatment with sap significantly decreased Bax expression and increased Bcl-2 expression 7 h after ethanol administration when compared with the negative control. The data suggest that A. okamotoanum sap pre-treatment may reduce the alcohol-induced oxidative stress in the rat liver.

울릉도 나리분지 주변 산림의 임분구조 및 동태

울릉도의 성인봉을 중심으로 나리분지와 주변 산림에 대한 지속가능한 보전을 위한 생태적 기초 자료를 제공하고자 나리분지 내 산림과 외륜의 동, 서, 북사면의 산림에 대하여 군락생태학적 방법으로 임분 구조 및 종 조성 특성을 조사 분석 하였다. 조사 대상 산림 내 임분의 층위 별 중요치를 산출하여 비교 분석한 결과, 나리분지 외륜산림 방위 및 고저 별 대부분의 임분에서는 너도밤나무와 고로쇠나무가 대체로 우점하는 경향이었으며, 임분간 식물 종의 조성에서도 큰 차이를 보이지 않았다. 그러나 나리분지내의 산림에서는 너도밤나무림, 두메오리나무림, 소나무림, 낙엽활엽수림의 다양한 임분이 형성되어 있었고, 임분에 따라 종 조성도 큰 차이를 보였다. 그리고 임분의 성숙도와 안정도 등 간접적인 군락의 속성을 파악하기 위하여 종 다양도를 비교 분석한 결과 임분의 각 층위에서 모두 나리분지 내 산림이 외륜의 산림에 비해 높은 종 다양도를 보였으며, 나리분지 내 산림에서는 소나무림과 낙엽활엽수림이 너도밤나무와 두메오리나무림에 비해 각 층위에서 대체로 높은 종 다양도를 보였다. 또한 산림의 방위 및 고저 별 임분에 대한 유사성을 추정하기 위해서 S<TEX>$\O$</TEX>rensen의 유사도계수(Cs)를 비교 분석한 결과 동, 서 북사면과 나리분지 내 산림간 유사도 지수는 0.68~0.69의 범위로서 차이가 거의 없었고, 능선부와 산복부, 산록부, 평탄지간 유사도 지수는 0.85~0.95의 범위로서 거의 동일한 임분형을 보였으며, 나리분지 내 네 임분 간 유사도 지수도 0.66~0.88의 범위로 높은 유사도를 보였다. 나리분지 외륜의 능선부와 산복부, 산록부, 평탄지에 대한 산림의 천이의 진행에 따라 임분구조 및 개체군의 동태를 예측하기 위하여 주요 구성종의 직경급 분포도를 작성한 결과 다소의 형태적 차이는 있었지만 대체로 정규분포형에 가까운 종형(Bell-shape)을 이루고 있었으며, 이들 산림 내 임분은 대체로 안정적으로 유지될 것으로 판단되었다. 따라서 성인봉을 포함한 나리분지와 외륜 산림의 임분들은 지형적 특성에도 불구하고 대체로 구조와 종조성에 있어서 높은 유사도를 보였으며, 기후변화에 의한 임분의 단순화가 지속될 것으로 판단되어, 산림 내 생물 종 및 생태계 다양성에 대한 보전과 관리 대책이 필요하다. For the sustainable conservation of forests within and around the somma of Nari basin in Ulleung Island, the stand structure and dynamics with the aspect, altitude and stand types were estimated by using analyses of importance value, plant species diversity, S<TEX>$\o$</TEX>rensen's similarity index and distributions of diameter classes. Results of the importance value analysis with vegetation stories on each stand showed that Fagus engleriana and Acer okamotoanum were dominant in most stands regardless of the aspect and altitude of the forest around the somma of Nari basin and the plant species composition among stands was not significantly different. The forest within Nari basin was composed of pine, beech, alder and deciduous-mixed stand. Moreover, the species composition was greatly different among the four stands. The diversity of plant species within stand was in general higher within Nari basin than around the somma, and among stands within Nari basin, the plant species diversity of pine and deciduous-mixed stand showed higher values than that of beech and alder stands. The similarity index among stands with aspect and altitude showed that the index among stands of eastern, western and northern slope in forest around the somma and forest within the basin ranged from 0.68 to 0.69, and the similarity among four stands with altitude was very high having index range from 0.85 to 0.95. The patterns of diameter class distribution of the major dominant species from four altitude classes followed an almost normal bell-shaped distribution. The results were interpreted as an indication that these forests will in general maintain a stable stand structure. Therefore, despite diverse topographic features around Nari basin, the stand structure and plant species composition among stands were not diversified as expected. For the conservation of diversity of forest plant species and of forest ecosystems, a promising and intensive program should be considered.

Antioxidant activity of cleomiscosins A and C isolated fromAcer okamotoanum

Phytochemical investigation of Acer okamotoanum leaf and twig led to the isolation of two coumarinolignans, cleomiscosin A (1) and cleomiscosin C (2). Here, we found that 2 dose-dependently inhibits LDL oxidation mediated by either catalytic copper ions (Cu2+) or free radicals generated with the azo compound 2,2'-azobis-(2-amidinopropane)dihydro-chloride (AAPH) with IC50s of 29.5 and 11.9 microM, respectively. By electrophoretic analysis, we also observed that 2 protects apolipoprotein B-100 (apoB-100) against Cu2+-induced fragmentation (65.3% inhibition at 5 microM). Furthermore, fluorescence analyses clearly indicated that both 1 and 2 protect against the oxidative modification of apoB-100 induced by either Cu2+ or HOCl (1, IC50s of 13.4 and 8.1 microM, respectively; 2, IC50s of 23.6 and 3.9 microM, respectively). These findings suggest that 1 and 2 could be beneficial in preventing LDL oxidation in atherosclerotic lesions.

Isolation of constituents and anti-complement activity fromAcer okamotoanum

A novel acylated sterol glucoside (1) along with four known compounds, beta-amyrin acetate (2), 3beta,24-dihydroxytaraxer-14-ene (3), cleomiscosin A (4), and cleomiscosin C (5), were isolated from the leaf and twig of Acer okamotoanum Nakai (Aceraceae). The structure of the new compound was determined to be beta-sitosterol glucoside-3'-O-hexacosanoicate based on chemical and spectroscopic analyses. In addition, the novel compound was found to exhibit a significant inhibitory effect (IC50 value of 0.2 microM) on the complement system activated by the classical pathway.

울릉도 산림식생의 공간분포 및 환경과의 상관관계 분석

본 연구는 Z-M학파의 식물사회학적 방법으로 울릉도 산림식생의 유형을 분류하고 그 공간적 분포 양상을 지도화하는데 있다. 이 지역 산림식생은 크게 우산고로쇠나무군락군의 산지 식생형과 해국군락군의 해안 저지식생형으로 양분되었으며, 군락 수준에서의 식생단위는 6개 군락, 16개 군,그리고7개 소군 등 3개 범주역에서 모두 22개 유형으로 구분되었다. 식생도 작성 면적은 5,544.9 ha이며, 이 중 너도밤나무군락이 35.2%인 1,951 ha로 가장 넓은 분포역을 나타내었으며 다음으로 송악군락 1,196 ha (21.6%), 동백나무군락 1,104 ha (19.9%), 말오줌나무군락 612.0 ha (11.0%), 해국군락 506 ha (9.1%), 솔송나무-섬 잣나무군락 174.0 ha (3.1%) 등의 순으로 나타났다. CCA 분석에 의한 식생단위와 토양인자와의 상관관계를 보면, 해안식생형에서는 <TEX>$Mg^{2+}$</TEX>, pH, <TEX>$Ca^{2+}$</TEX>등이 양의 관계, 그리고 산지식생유형에서는 전질소, 탄소, C/N율의 유기물 함량과 양이온 치환 용량 등은 높은 상관을 나타내었다. 입지환경과 종 다양성의 상관관계를 보면 해발과 사면 방향은 일정한 경향을 보이지 않지만 지형과 경사도 그리고 우점하고 있는 식생에 따라 많은 영향을 받고 있음을 알 수 있었다. This study was carried out to classify all forest vegetation types in Ulleung Island, Korea using the methodology of the Z.-M. school's phytosociology, and map out the spatial distribution patterns of those vegetation types. The forest vegetation was classified into the mountain forest type (Acer okamotoanum community group) and maritime forest type (Artemisia scoparia community group). Vegetation units at the community level were divided into three categories; six communities, sixteen groups, and seven subgroups, giving a total of 22 communities. Total area for mapping was 5,544.9 ha, of which Fagus engleriana community accounted for 1,952 ha (35.2%), Hedera rhambea community ror 1,196 ha (21.6%), Camellia japonica community for 1,104 ha (19.9%), Sambucus sieboldiana var. pendula community for 612 ha (11.0%), Aster spathulifolius community for 506 ha (9.1%), and Tsuga sieboldii - Pinus parviflora community for 174 ha (3.1%). According to canonical correspondence analysis (CCA), variables such as <TEX>$Mg^{2+}$</TEX>, pH, <TEX>$Ca^{2+}$</TEX> were positively correlated in maritime vegetation types, and variables such as total nitrogen, carbon content, C/N ratio and ration exchange capacity (CEC) were highly correlated in mountain vegetation types, respectively. The sea level and the slope direction were not showing regular trend as a factor to decide on species diversity, evenness and richness in this research area. But it seems to be affected by topography, slope degree and dominance vegetation.