Quercus Gilva Research Articles

Comparative and phylogenetic analysis of chloroplast genomes from four species in Quercus section Cyclobalanopsis

The Quercus L. species is widely recognized as a significant group in the broad-leaved evergreen forests of tropical and subtropical East Asia. These plants hold immense economic value for their use as firewood, furniture, and street trees. However, the identification of Quercus species is considered challenging, and the relationships between these species remain unclear. In this study, we sequenced and assembled the chloroplast (cp.) genomes of four Quercus section Cyclobalanopsis species (Quercus disciformis, Quercus dinghuensis, Quercus blackei, and Quercus hui). Additionally, we retrieved six published cp. genome sequences of Cyclobalanopsis species (Quercus fleuryi, Quercus pachyloma, Quercus ningangensis, Quercus litseoides, Quercus gilva, and Quercus myrsinifolia). Our aim was to perform comparative genomics and phylogenetic analyses of the cp. whole genome sequences of ten Quercus section Cyclobalanopsis species. The results revealed that: (1) Quercus species exhibit a typical tetrad structure, with the cp. genome lengths of the newly sequenced species (Q. disciformis, Q. dinghuensis, Q. blakei, and Q. hui) being 160,805 bp, 160,801 bp, 160,787 bp, and 160,806 bp, respectively; (2) 469 SSRs were detected, among which A/T base repeats were the most common; (3) no rearrangements or inversions were detected within the chloroplast genomes. Genes with high nucleotide polymorphism, such as rps14-psaB, ndhJ-ndhK, rbcL-accD, and rps19-rpl2_2, provided potential reference loci for molecular identification within the Cyclobalanopsis section; (4) phylogenetic analysis showed that the four sections of Cyclobalanopsis were grouped into sister taxa, with Q. hui being the first to diverge from the evolutionary branch and Q. disciformis being the most closely related to Q. blackei. The results of this study form the basis for future studies on taxonomy and phylogenetics.

Predicting Quercus gilva distribution dynamics and its response to climate change induced by GHGs emission through MaxEnt modeling

Quercus gilva, an evergreen tree species in Quercus section Cyclobalanopsis, is an ecologically and economically valuable species in subtropical regions of East Asia. Predicting the impact of climate change on potential distribution of Q. gilva can provide a scientific basis for the conservation and utilization of its genetic resources, as well as for afforestation. In this study, 74 distribution records of Q. gilva and nine climate variables were obtained after data collection and processing. Current climate data downloaded from WorldClim and future climate data predicted by four future climate scenarios (2040s SSP1-2.6, 2040s SSP5-8.5, 2060s SSP1-2.6, and 2060s SSP5-8.5) mainly based on greenhouse gases emissions of distribution sites were used in MaxEnt model with optimized parameters to predict distribution dynamics of Q. gilva and its response to climate change. The results showed that the predicted current distribution was consistent with natural distribution of Q. gilva, which was mainly located in Hunan, Jiangxi, Zhejiang, Fujian, Guizhou, and Taiwan provinces of China, as well as Japan and Jeju Island of South Korea. Under current climate conditions, precipitation factors played a more significant role than temperature factors on distribution of Q. gilva, and precipitation of driest quarter (BIO17) is the most important restriction factor for its current distribution (contribution rate of 57.35%). Under future climate conditions, mean temperature of driest quarter (BIO9) was the essential climate factor affecting future change in potential distribution of Q. gilva. As the degree of climatic anomaly increased in the future, the total area of predicted distribution of Q. gilva showed a shrinking trend (decreased by 12.24%–45.21%) and Q. gilva would migrate to high altitudes and latitudes. The research results illustrated potential distribution range and suitable climate conditions of Q. gilva, which can provide essential theoretical references for the conservation, development, and utilization of Q. gilva and other related species.

Comparison of chloroplast genomes and phylogenetic analysis of four species in Quercus section Cyclobalanopsis

The identification in Quercus L. species was considered to be difficult all the time. The fundamental phylogenies of Quercus have already been discussed by morphological and molecular means. However, the morphological characteristics of some Quercus groups may not be consistent with the molecular results (such as the group Helferiana), which may lead to blurring of species relationships and prevent further evolutionary researches. To understand the interspecific relationships and phylogenetic positions, we sequenced and assembled the CPGs (160,715 bp-160842 bp) of four Quercus section Cyclobalanopsis species by Illumina pair-end sequencing. The genomic structure, GC content, and IR/SC boundaries exhibited significant conservatism. Six highly variable hotspots were detected in comparison analysis, among which rpoC1, clpP and ycf1 could be used as molecular markers. Besides, two genes (petA, ycf2) were detected to be under positive selection pressure. The phylogenetic analysis showed: Trigonobalanus genus and Fagus genus located at the base of the phylogeny tree; The Quercus genus species were distincted to two clades, including five sections. All Compound Trichome Base species clustered into a single branch, which was in accordance with the results of the morphological studies. But neither of group Gilva nor group Helferiana had formed a monophyly. Six Compound Trichome Base species gathered together in pairs to form three branch respectively (Quercus kerrii and Quercus chungii; Quercus austrocochinchinensis with Quercus gilva; Quercus helferiana and Quercus rex). Due to a low support rate (0.338) in the phylogeny tree, the interspecies relationship between the two branches differentiated by this node remained unclear. We believe that Q. helferiana and Q. kerrii can exist as independent species due to their distance in the phylogeny tree. Our study provided genetic information in Quercus genus, which could be applied to further studies in taxonomy and phylogenetics.

Population Survey Combined with Genomic-Wide Genetic Variation Unravels the Endangered Status of Quercus gilva

Since the Anthropocene, biodiversity loss owing to human activity and climate change has worsened. Quercus gilva is an evergreen oak species native to China, Japan, and South Korea and is threatened by a long history of human impact. The purpose of this study was to (1) reassess the threatened category of Q. gilva based on a detailed survey, and (2) identify the genetic structure and diversity of Q. gilva based on genomic data. First, we conducted a detailed survey of the populations in China. Second, we collated all the literature and information. Finally, genome-wide genetic variation was analyzed based on 65 individuals from 22 populations. We found that Q. gilva has suffered rapid population decline, and at present, most populations are very small. The evolutionary path of Q. gilva was from the southwest to east of China and then to Japan and South Korea. Quercus gilva showed no distinct genetic structure and had a relatively low genetic diversity. Among the 22 populations, most populations in southwestern China, South Korea, and Japan had high genetic diversity. The populations in Jingning (Zhejiang province; ZJN), Wuyuan (Jinaxi province; JWY), and Zherong (Fujian province; FZR) suffered a strong bottleneck. In conclusion, Q. gilva is an endangered species native to East Asia. Because of the very low genetic diversity of Q. gilva and most populations are small, we need to (1) strengthen the protection of this species, (2) conduct conservation actions with in-situ reinforcement populations, and (3) select populations with high genetic diversity as provenances for afforestation efforts. Finally, we suggest that in the future, genetic diversity should be considered as the sixth criterion for IUCN to evaluate the threatened category.

Antiacne and Anti-Inflammatory Effects of Phenolic Compounds from Quercus acutissima Carruth. Leaves.

Quercus plants are widely distributed in Korea and have been used for their antiallergic and anti-inflammatory properties to treat dermatitis. The phenolic compounds of Quercus acutissima Carruth (QA) are estimated to have antioxidant and anti-inflammatory activities, based on the results of previous studies with Quercus mongilica, Quercus stenophylla, Quercus gilva Blame., and Quercus acuta Thunb. We yield QA extract and the isolated phenolic compounds (hyperoside (1), astragalin (2), kaempferol 3-O-(6″- galloyl)-β-D-glucopyranoside (KGG) (3), quercetin 3-O-(6″-O-galloyl)-β-D-glucopyranoside (QGG) (4), pedunculagin (5), and casuarinin (6)) and were identified using NMR. Among them, KGG (3) and QGG (4) were isolated for the first time from QA. QA extract and the isolated phenolic compounds demonstrated antioxidative, anti-inflammatory, and antiacne activities in RAW 264.7 mouse macrophage cells in vitro. 3-6 demonstrated strong inhibitory activities in the DPPH scavenging and NO production assay and anti-inflammatory and antiacne activities through western blotting (NLRP3, IL-1β, and 5α-reductase). The most outstanding activity in all experiments was casuarinin (6). The study findings suggest potential therapeutic candidates for acne.

Seasonality of Photosynthetic Physiology and Leaf Anatomy in Three Different Quercus L. Section Cyclobalanopsis Seedlings of Quercus chungii, Quercus gilva, and Quercus glauca in the Subtropical Region of South China

The increasing demand for precious timber resources promotes immediate efforts to develop high-valuable hardwood resources in afforestation. However, the lack of valuable tree species seedlings for afforestation and their ecological adaptability must primarily be addressed. To explore a valuable tree species for precious timber resourcing in afforestation, a comparative analysis of the characteristics of photosynthetic physiology and leaf anatomy in three different Quercus L. Section Cyclobalanopsis seedlings of Quercus chungii, Quercus gilva, and Quercus glauca was performed during three growth stages (July, September, and November) in South China. The results showed that there are significant differences in photosynthetic physiological characteristic parameters, chlorophyll content, and leaf anatomical structure among the three seedlings in each growth stage (p < 0.05). The photosynthetic parameters, i.e., Pn, Gs, Tr, WUE and Ci in each tree species all had the same trend of increase from July to September and decrease from September to November, and with a pick point in September during the three stages. The Pn in Q. chungii was higher than that in the other two species in each stage, and the highest Pn with an average value of 8.26 μmol·m−2·s−1 was obtained in September in Q. chungii, which was 13.77% and 20.06% higher than that of in Q. gilva and Q. glauca at the same time, respectively. Significant differences were also detected in the chlorophyll fluorescence of Fo, Fm, Fv/Fm, Y, ETR, qP, and NPQ among three seedlings within each growth stage from July to November (p < 0.05). The thickness of the mature leaf was decreased in order as Q. chungii, Q. glauca, and Q. gilva. From July to September, more notable changes were observed in Q. chungii in September, with a drop of 3.49% in leaf thickness, and a drop of 3.34% and 10.06% in the volume of palisade tissue and sponge tissue, respectively. Consequently, increasing tightness and deducing looseness were observed in Q. chungii. The principal component analysis (PCA) on photosynthesis and leaf anatomy showed that Q. chungii displayed a stronger photosynthetic physiology with a positive coordination on water, air, light, and heat. These findings facilitate the evaluation of ecological adaptability among the three Quercus seedlings and provide compelling evidence for the application of Q. chungii for precious timber resources in afforestation.

A chromosome-scale genome assembly of Quercus gilva: Insights into the evolution of Quercus section Cyclobalanopsis (Fagaceae).

Quercus gilva is an ecologically and economically important species of Quercus section Cyclobalanopsis and is a dominant species in evergreen broad-leaved forests in subtropical regions of East Asia. In the present study, we reported a high-quality chromosome-scale genome assembly of Q. gilva, the first reference genome for section Cyclobalanopsis, using the combination of Illumina and PacBio sequencing with Hi-C technologies. The assembled genome size of Q. gilva was 889.71 Mb, with a contig number of 773 and a contig N50 of 28.32 Mb. Hi-C scaffolding anchored 859.07 Mb contigs (96.54% of the assembled genome) onto 12 pseudochromosomes, with a scaffold N50 of 70.35 Mb. A combination of de novo, homology-based, and transcript-based predictions predicted a final set of 36,442 protein-coding genes distributed on 12 pseudochromosomes, and 97.73% of them were functionally annotated. A total of 535.64 Mb (60.20%) of repetitive sequences were identified. Genome evolution analysis revealed that Q. gilva was most closely related to Q. suber and they diverged at 40.35 Ma, and Q. gilva did not experience species-specific whole-genome duplication in addition to the ancient gamma (γ) whole-genome triplication event shared by core eudicot plants. Q. gilva underwent considerable gene family expansion and contraction, with 598 expanded and 6,509 contracted gene families detected. The first chromosome-scale genome of Q. gilva will promote its germplasm conservation and genetic improvement and provide essential resources for better studying the evolution of Quercus section Cyclobalanopsis.

Antioxidative and Circadian Rhythm Regulation Effect of Quercus gilva Extract

Herein, water and ethanol extracts were obtained from the leaves, branches, kernels, and pericarp of Quercus gilva and subsequently analyzed for antioxidant activity and circadian rhythm regulation effects. Candidate components that may affect circadian rhythm and antioxidant activity were investigated to discover potential functional materials. Antioxidant activity was analyzed via 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity assays, showing that the hot water extract exhibited higher activity than that of the ethanol extract. In particular, the branch extract showed high antioxidant activity. By measuring total contents of polyphenols, flavonoids, and tannins, the hot water branch extract showed the highest concentrations, highlighting their significant contribution to the antioxidant activity. Examination of the circadian rhythm regulation of each extract showed that the ethanol extract exhibited greater impacts on the circadian rhythm amplitude compared to the water extract. The branch ethanol extract induced circadian rhythm amplitude changes via clock gene Bmal1 expression regulation. Determination of 12 phenolic compound concentrations showed that the branch ethanol extract contained many phenolic compounds, including catechin. This suggests that these compounds affected circadian rhythm regulation. In conclusion, the hot water branch extract has potential as an natural antioxidant material, while the corresponding ethanol extract has potential as a functional material for regulating circadian rhythm.

α-Glucosidase inhibitor and antioxidant activity of procyanidin, an isolated compound from Quercus gilva Blume leaves

α-Glucosidase inhibitor and antioxidant activity of procyanidin, an isolated compound from Quercus gilva Blume leaves

A Disjunctive Marginal Edge of Evergreen Broad-Leaved Oak (Quercus gilva) in East Asia: The High Genetic Distinctiveness and Unusual Diversity of Jeju Island Populations and Insight into a Massive, Independent Postglacial Colonization.

Jeju Island is located at a marginal edge of the distributional range of East Asian evergreen broad-leaved forests. The low genetic diversity of such edge populations is predicted to have resulted from genetic drift and reduced gene flow when compared to core populations. To test this hypothesis, we examined the levels of genetic diversity of marginal-edge populations of Quercus gilva, restricted to a few habitats on Jeju Island, and compared them with the southern Kyushu populations. We also evaluated their evolutionary potential and conservation value. The genetic diversity and structure were analyzed using 40 polymorphic microsatellite markers developed in this study. Ecological Niche Modeling (ENM) has been employed to develop our insights, which can be inferred from historical distribution changes. Contrary to our expectations, we detected a similar level of genetic diversity in the Jeju populations, comparable to that of the southern Kyushu populations, which have been regarded as long-term glacial refugia with a high genetic variability of East Asian evergreen trees. We found no signatures of recent bottlenecks in the Jeju populations. The results of STRUCTURE, neighbor-joining phylogeny, and Principal Coordinate Analysis (PCoA) with a significant barrier clearly demonstrated that the Jeju and Kyushu regions are genetically distinct. However, ENM showed that the probability value for the distribution of the trees on Jeju Island during the Last Glacial Maximum (LGM) converge was zero. In consideration of these results, we hypothesize that independent massive postglacial colonization from a separate large genetic source, other than Kyushu, could have led to the current genetic diversity of Jeju Island. Therefore, we suggest that the Jeju populations deserve to be separately managed and designated as a level of management unit (MU). These findings improve our understanding of the paleovegetation of East Asian evergreen forests, and the microevolution of oaks.

Heissiella donguri sp. nov. (Hemiptera: Heteroptera: Tingidae) feeding on Quercus gilva (Fagaceae): First representative of the genus from Japan.

The lace bug genus Heissiella Péricart, 1984 (Hemiptera: Heteroptera: Tingidae) is recorded from Japan for the first time, and a new species, which has been recorded as 'Tingis (Tropidocheila) sp.' or 'Tingis (Tropidocheila) shaowuana Drake Maa, 1953' (misidentification) by previous authors, is described under the name of H. donguri sp. nov. This new species was found on the leaves of Quercus gilva Blume (Fagaceae) in the laurilignosa ecosystem of Honshu and Kyushu, extending the known distribution range of the genus into the Palaearctic Region. The distribution range and the host plant relationship of the new species are discussed. A key to all described species of the genus and a photograph of a living individual for the new species are also presented.

Heterogony in Cycloneuroterus (Hymenoptera: Cynipidae: Cynipini) From Rearing Experiments and DNA Barcoding.

Heterogony was confirmed in the cynipid genus Cycloneuroterus Melika and Tang in rearing experiments with DNA barcoding. These experiments involved Cycloneuroterus gilvus Tang and Melika, which was previously only described from the sexual generation adult. The first rearing experiment was conducted using unidentified asexual generation females collected from Quercus gilva Blume, and gall formation by the sexual generation offspring was confirmed on folded or unfolded young leaves of Q. gilva. The second experiment was conducted using sexual generation males and females reared from the leaf galls collected from Q. gilva, and gall formation by the asexual generation offspring was observed on leaves of Q. gilva. Based on the morphological features of the sexual generation adults and galls, this species was identified as C. gilvus. The species identity of wasp specimens of sexual and asexual generations used in the rearing experiments was cross-checked using DNA barcoding with the partial sequences of the cytochrome c oxidase subunit I (COI) region (658 bp). The asexual generation adult and gall of C. gilvus are described based on these results. The importance of ‘closing the life cycle,’ in this case a demonstration of heterogony, in oak gall wasps (Cynipini) is discussed.

The complete chloroplast genome sequence of Quercus gilva（Fagaceae）

Quercus gilva is classified as the national second-class protective tree species in China and is widely distributed in Middle East Asia. We determined the complete chloroplast genome sequence for Q. gilva using Illumina sequencing data. The complete chloroplast sequence is 160,763 bp, including large single-copy (LSC) region of 90,292 bp, small single-copy (SSC) region of 18,831 bp, and a pair of invert repeats (IR) regions of 25,820 bp. Plastid genome contains 128 genes, 80 protein-coding genes, 40 tRNA genes, and 8 rRNA genes. Phylogenetic analysis based on 26 chloroplast genomes indicates that Q. gilva is closely related to Q. sichourensis in Fagaceae.

Effects of elevated CO2 concentration and increased temperature on leaf quality responses of rare and endangered plants

BackgroundIn the study, the effects of elevated CO2 and temperature on the nitrogen content, carbon content, and C:N ratio of seven rare and endangered species (Quercus gilva, Hibiscus hambo, Paliurus ramosissimus, Cicuta virosa, Bupleurum latissimum, Viola raddeana, and Iris dichotoma) were examined under control (ambient CO2 + ambient temperature) and treatment (elevated CO2 + elevated temperature) for 3 years (May 2008 and June 2011).ResultsElevated CO2 concentration and temperature result in a decline in leaf nitrogen content for three woody species in May 2009 and June 2011, while four herb species showed different responses to each other. The nitrogen content of B. latissimum and I. dichotoma decreased under treatment in either 2009 and 2011. The leaf nitrogen content of C. virosa and V. raddeana was not significantly affected by elevated CO2 and temperature in 2009, but that of C. virosa increased and that V. raddeana decreased under the treatment in 2011. In 2009, it was found that there was no difference in carbon content in the leaves of the six species except for that of P. ramosissimus. On the other hand, while there was no difference in carbon content in the leaves of Q. gilva in the control and treatment in 2011, carbon content in the leaves of the remaining six species increased due to the rise of CO2 concentration and temperature. The C:N ratio in the leaf of C. virosa grown in the treatment was lower in both 2009 and 2011 than that in the control. The C:N ratio in the leaf of V. raddeana decreased by 16.4% from the previous year, but increased by 28.9% in 2011. For the other five species, C:N ratios increased both in 2009 and 2011. In 2009 and 2011, chlorophyll contents in the leaves of Q. gilva and H. hamabo were higher in the treatment than those in the control. In the case of P. ramosissimus, the ratio was higher in the treatment than that in the control in 2009, but in 2011, the result was the opposite. Among four herb species, the chlorophyll contents in the leaves of C. virosa, V. raddeana, and I. dichotoma did not show any difference between gradients in 2009, but decreased due to the rise of CO2 concentration and temperature in 2011. Leaf nitrogen and carbon contents, C:N ratio, and chlorophyll contents in the leaves of seven rare and endangered species of plant were found to be influenced by the rise and duration of CO2 concentration and temperature, species, and interaction among those factors.ConclusionsThe findings above seem to show that long-term rise of CO2 concentration, and temperature causes changes in physiological responses of rare and endangered species of plant and the responses may be species-specific. In particular, woody species seem to be more sensitive to the rise of CO2 concentration and temperature than herb species.

Anti-Inflammatory and Anti-Urolithiasis Effects of Polyphenolic Compounds from Quercus gilva Blume.

Quercus gilva Bume (QGB, family Fagaceae) is a tall evergreen oak species tree that grows in warm temperate regions in Korea, Japan, China and Taiwan. Quercus plants have long been the basis of traditional medicines. Their clinical benefits according to traditional medicine include relief of urolithiasis, tremors and inflammation. In the present study, the anti-urolithiasis activity including anti-inflammatory and anti-oxidative activities, of some phenolic compounds isolated from QGB were described. Seven compounds were isolated and identified as picraquassioside D (1), quercussioside (2), (+)-lyoniresinol-9′α-O-β-d-xylopyranoside (3), (+)-catechin (4), (−)-epicatechin (5), procyanidin B-3 (6), and procyanidin B-4 (7). Compounds 5–7 showed potent anti-oxidative and anti-inflammatory activities. These compounds were further tested for their inhibition of the gene expression of the inflammatory cytokines. The three compounds 5–7 showed dose-dependent inhibitory activities on gene expression of COX-2 and IL-1β. In vivo, urolithiasis was induced more effectively in an animal model of acute urolithiasis by the administration of QGB extract. These results indicate the potential of compounds from QGB in the treatment of urolithiasis.

α-Glucosidase inhibitor produced by an endophytic fungus, Xylariaceae sp. QGS 01 from Quercus gilva Blume

Xylariaceae sp. QGS 01, an endophytic fungus isolated from the stem of Quercus gilva Blume showed high α-glucosidase inhibitory activity. α-Glucosidase inhibitor have the role as one of carbohydrate-hydrolyzing enzymes to postpone absorption of glucose in the digestive organs. The α-glucosidase inhibitor constituents were isolated from the ethyl acetate extract of the mycellium of endophytic fungi Xylariaceae sp. QGS 01 using a bioassay-guided fractionation technique. Further separation and purification of the active fraction led to the isolation of constituents with strong inhibitory activities against α-glucosidase: 8-hydroxy-6,7-dimethoxy-3-methylisocoumarine (1) with inhibitory concentration (IC50) values against α-glucosidase from Saccharomyces cerevisiae of 41.75μg/mL, while quercetin as the standard had an IC50 value of 4.80μg/mL. The results of the present study showed that the endophytic fungus Xylariaceae sp. QGS 01 is potentially a rich source of antidiabetic medicine.

Genetic structure of Quercus gilva Blume in Japan as revealed by chloroplast DNA sequences

Quercus gilva (Blume) is an evergreen oak species that is native to Japan, China, and Taiwan. Because of a long history of human impact, this species is threatened with extinction in several regions of Japan. The objective of this study was to identify the genetic structure of Q. gilva based on chloroplast DNA (cpDNA) sequencing analysis. We collected 123 samples from 25 populations in Japan, 8 samples from 1 population in China, and 46 samples from 5 populations in Taiwan. Approximately 1815 bp of cpDNA was sequenced for each of the 177 samples. Thirteen haplotypes were detected, with no cross-region distribution of haplotypes among the three geographically separated countries. There were large genetic differences among populations (GST = 0.824, [Formula: see text] = 0.937). Six haplotypes (haplotypes 1, 2, 3, 4a, 4b, and 5) were detected in Japan; haplotype 4a was the most common, detected from 20 populations, and the other rare haplotypes, except for haplotype 4b, occurred at the edge of the species’ distribution. In addition, four haplotypes (haplotypes 1, 2, 3, and 5) were quite different from the predominant haplotype (haplotype 4a), with more than four cpDNA mutations except for a mononucleotide repeat, suggesting that populations with these rare haplotypes should be conserved separately.

Determination of allelopathic potentials in plant species in Sino-Japanese floristic region by sandwich method and dish pack method

<p>The Sino-Japanese Floristic Region appears as one of the major centers of development of higher plants. This region have been relevant for the study of evolution and systematics of many flowering plants. The taxonomic richness of endemic plant species in this region have survived several years of extreme climate conditions. Endemic mountainous plant species that have survived extreme climate conditions are of allelopathic and medicinal interest. For this reason, 251 plant species collected from the Sino-Japanese Floristic Region were screened for allelopathic plant species. Sandwich method and dish pack method were respectively used to screen plant leaf leachates and volatile materials with lettuce (<em>Lactuca sativa</em> CV. Great Lakes 366) as receptor plant. Among the 84 species that showed inhibitory effect on lettuce radicle elongation in our sandwich bioassay, <em>Photinia glabra </em>showed complete inhibition of lettuce radicle elongation (0% radicle elongation). In the dish pack bioassay, <em>Photinia glabra</em>, <em>Liquidambar styraciflua</em>, and <em>Cinnamomum camphora</em> (90.6%, 61.4%, and 50.2% respectively) were among the nine species that were observed with strong inhibitory effect on lettuce radicle growth. On the other hand, nine other species promoted lettuce radicle growth when compared to the control. <em>Aesculus turbinata</em> and <em>Quercus gilva</em> were the species with the highest growth stimulatory effect (33.0% and 16.1% respectively). We hereby present <em>Photinia glabra </em>as an allelopathic candidate species for both leachate and volatile compounds.</p>

Antioxidant and α-glucosidase inhibitor activities of natural compounds isolated from Quercus gilva Blume leaves

ObjectiveTo isolate and investigate antioxidant and α-glucosidase inhibitor compounds in the leaves of Quercus gilva Blume (Q. gilva). MethodsDry leaves of Q. gilva were extracted with methanol and the methanolic extract was further separated by silica gel column chromatography using several solvents with increasing polarity. The antioxidant activities of the isolated compounds were evaluated using various in vitro assays: 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, hydrogen peroxide radical scavenging activity, β-carotene bleaching assay, and reducing power assay. The α-glucosidase inhibitory assay was conducted against α-glucosidase from Saccharomyces cerevisiae. ResultsThree compounds were isolated and their structures were identified as catechin (1), epicatechin (2), and tiliroside (3) using an instrumental analysis. Compound 2 had higher antioxidant activity with inhibitory concentrations (IC50) of (22.55 ± 2.23) μmol/L than that of quercetin, which was used as the standard, with an IC50 of (28.08 ± 2.39) μmol/L, followed by compound 1 with IC50 of (40.86 ± 3.45) μmol/L. On the other hand, compound 3 had the lowest antioxidant activity with an IC50 of (160.24 ± 8.15) μmol/L. However, compound 3 had the highest α-glucosidase inhibitory activity with an IC50 of (28.36 ± 0.11) μmol/L, followed by compounds 1 and 2 with (168.60 ± 5.15) and (920.60 ± 10.10) μmol/L, respectively. ConclusionsThe results obtained for the antioxidant activities and α-glucosidase inhibitory activities in a methanolic extract from the leaves of Q. gilva confirmed the potential of this plant as a source of natural antioxidants and antidiabetic medicine.

국내 개가시나무 개체군의 분포 및 동태

국내 개가시나무 개체군의 분포 및 동태