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Yongeui Choi - One of the best experts on this subject based on the ideXlab platform.

  • β amyrin synthase esbas and β amyrin 28 oxidase cyp716a244 in oleanane type triterpene saponin biosynthesis in Eleutherococcus senticosus
    Phytochemistry, 2017
    Co-Authors: Jung Yeon Han, Hwansu Hwang, Yongeui Choi
    Abstract:

    Siberian ginseng (Eleutherococcus senticosus) is a woody medical shrub belonging to the Araliaceae family. E. senticosus contains various types of saponins, including oleanane, noroleanane, lupane, and 3,4-secolupane types, depending on the aglycone structure. Oleanane-type triterpenes are the major saponin components in E. senticosus. Two enzymes (β-amyrin synthase and β-amyrin 28-oxidase) are essential for oleanane-type saponin biosynthesis from 2,3-oxidosqualene. In the present study, two full-length cDNAs encoding EsBAS and CYP716A244 were isolated based on transcriptomics analysis of plant leaves. Both β-amyrin synthase (EsBAS) and β-amyrin 28-oxidase (CYP716A244), isolated from E. senticosus, were functionally characterised. β-amyrin production was confirmed by heterologous expression of the EsBAS gene in yeast and tobacco. Oleanolic acid production was confirmed by co-expression of both EsBAS and CYP716A244 in engineered yeast and transgenic tobacco.

  • transcriptomic analysis of siberian ginseng Eleutherococcus senticosus to discover genes involved in saponin biosynthesis
    BMC Genomics, 2015
    Co-Authors: Hwansu Hwang, Hyoshin Lee, Yongeui Choi
    Abstract:

    Eleutherococcus senticosus, Siberian ginseng, is a highly valued woody medicinal plant belonging to the family Araliaceae. E. senticosus produces a rich variety of saponins such as oleanane-type, noroleanane-type, 29-hydroxyoleanan-type, and lupane-type saponins. Genomic or transcriptomic approaches have not been used to investigate the saponin biosynthetic pathway in this plant. In this study, de novo sequencing was performed to select candidate genes involved in the saponin biosynthetic pathway. A half-plate 454 pyrosequencing run produced 627,923 high-quality reads with an average sequence length of 422 bases. De novo assembly generated 72,811 unique sequences, including 15,217 contigs and 57,594 singletons. Approximately 48,300 (66.3%) unique sequences were annotated using BLAST similarity searches. All of the mevalonate pathway genes for saponin biosynthesis starting from acetyl-CoA were isolated. Moreover, 206 reads of cytochrome P450 (CYP) and 145 reads of uridine diphosphate glycosyltransferase (UGT) sequences were isolated. Based on methyl jasmonate (MeJA) treatment and real-time PCR (qPCR) analysis, 3 CYPs and 3 UGTs were finally selected as candidate genes involved in the saponin biosynthetic pathway. The identified sequences associated with saponin biosynthesis will facilitate the study of the functional genomics of saponin biosynthesis and genetic engineering of E. senticosus.

  • effects of led on growth morphogenesis and eleutheroside contents of in vitro cultured plantlets of Eleutherococcus senticosus maxim
    The Korean Journal of Medicinal Crop Science, 2009
    Co-Authors: Jaehun Jeong, Youngseon Kim, Heungkyu Moon, Sungjin Hwang, Yongeui Choi
    Abstract:

    The effects of red, blue, and far-red light by illumination of light emitting diodes (LEDs) on growth, morphogenesis and eleutheroside contents of in vitro plantlets of Eleutherococcus senticosus were examined. As a control, plantlets were grown under a broad spectrum white fluorescent lamp (16/8 h illumination). The length of plantlets grown under the red/blue LEDs was taller than those under fluorescent lamps. Leaf area, root length and fresh weight of plantlets were highest under blue light compared to other kinds of light sources. Chlorophyll contents in plantlets grown under fluorescent lamps were higher than those in plantlets grown under LED illumination. Production of eleuthroside B and E in plantlets was highest under blue LED. However, production of eleuthroside E1 was highest under fluorescent lamps. These results suggest that plant growth and eleuthroside accumulation can be controlled by wave length of light under LED illumination system.

  • cellular change and callose accumulation in zygotic embryos of Eleutherococcus senticosus caused by plasmolyzing pretreatment result in high frequency of single cell derived somatic embryogenesis
    Protoplasma, 2006
    Co-Authors: Xiangling You, Yongeui Choi
    Abstract:

    Eleutherococcus senticosus zygotic embryos were pretreated with 1.0 M mannitol or sucrose for 3–24 h. This pretreatment resulted in a high frequency of somatic-embryo formation on hormone-free medium. All the somatic embryos developed directly and independently from single epidermal cells on the surface of zygotic embryos after plasmolyzing pretreatment. Scanning electron microscopic observation revealed that the epidermal cells of hypocotyls rapidly became irregular and showed a random orientation before somatic-embryo development commenced. At the same time, the epidermal cells in the untreated control remained regular. Callose concentration determined by fluorometric analysis increased sharply in E. senticosus zygotic embryos after plasmolyzing pretreatment but remained low in the untreated control. Aniline blue fluorescent staining of callose showed that the plasmolyzing pretreatment of zygotic embryos resulted in heavy accumulation of callose between the plasma membrane and cell walls. On the basis of these results, we suggest that plasmolyzing pretreatment of zygotic embryos induces the accumulation of callose, and the interruption of cell-to-cell communication imposed by this might stimulate the reprogramming of epidermal cells into embryogenically competent cells and finally induce somatic-embryo development from single cells.

  • overexpression of squalene synthase in Eleutherococcus senticosus increases phytosterol and triterpene accumulation
    Phytochemistry, 2005
    Co-Authors: Jaehun Jeong, Chagyun Shin, Seogcho Lo, Kiwon Yu, Emiko Harada, Yongeui Choi
    Abstract:

    Abstract Squalene synthase (SS) catalyzes the first committed step in sterol and triterpenoid biosynthesis. Transgenic Eleutherococcus senticosus Rupr. and Maxim. plants were generated by introducing an SS-encoding gene derived from Panax ginseng (PgSS1) together with genes expressing hygromycin phosphotransferase and green fluorescent protein (GFP) through Agrobacterium-mediated transformation. Early globular embryo clusters developing from the embryogenic callus were used for Agrobacterium-mediated transformation. Transformants were selected on Murashige Skoog medium containing 25 mg/L hygromycin. Hygromycin-resistant somatic embryos developed into plants after the cotyledonary embryos were treated with 14.4 μM gibberellic acid. Transformation was confirmed by polymerase chain reaction, Southern, and GFP analyses. The SS enzyme activity of the transgenic plants was up to 3-fold higher than that of wild-type plants. In addition, GC-MS and HPLC analysis revealed that phytosterols (β-sitosterol and stigmasterol) as well as triterpene saponins (ciwujianosides B (1), C1 (2), C2 (3), C3 (4), C4 (5), D1 (6) and D2 (7)) levels in transgenic E. senticosus were increased by 2- to 2.5-fold. These results suggest that the metabolic engineering of E. senticosus to enhance production of phytosterols and triterpenoids by introducing the PgSS1 gene was successfully achieved by Agrobacterium-mediated genetic transformation.

Xiangling You - One of the best experts on this subject based on the ideXlab platform.

  • transcriptome profiling and digital gene expression by deep sequencing in early somatic embryogenesis of endangered medicinal Eleutherococcus senticosus maxim
    Gene, 2016
    Co-Authors: Lei Tao, Qiuyu Wang, Yue Zhao, Hongmei Yuan, Lijuan Zhao, Wendong Guo, Xiangling You
    Abstract:

    Somatic embryogenesis (SE) has been studied as a model system to understand molecular events in physiology, biochemistry, and cytology during plant embryo development. In particular, it is exceedingly difficult to access the morphological and early regulatory events in zygotic embryos. To understand the molecular mechanisms regulating early SE in Eleutherococcus senticosus Maxim., we used high-throughput RNA-Seq technology to investigate its transcriptome. We obtained 58,327,688 reads, which were assembled into 75,803 unique unigenes. To better understand their functions, the unigenes were annotated using the Clusters of Orthologous Groups, Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes databases. Digital gene expression libraries revealed differences in gene expression profiles at different developmental stages (embryogenic callus, yellow embryogenic callus, global embryo). We obtained a sequencing depth of >5.6 million tags per sample and identified many differentially expressed genes at various stages of SE. The initiation of SE affected gene expression in many KEGG pathways, but predominantly that in metabolic pathways, biosynthesis of secondary metabolites, and plant hormone signal transduction. This information on the changes in the multiple pathways related to SE induction in E. senticosus Maxim. embryogenic tissue will contribute to a more comprehensive understanding of the mechanisms involved in early SE. Additionally, the differentially expressed genes may act as molecular markers and could play very important roles in the early stage of SE. The results are a comprehensive molecular biology resource for investigating SE of E. senticosus Maxim.

  • callose deposition is required for somatic embryogenesis in plasmolyzed Eleutherococcus senticosus zygotic embryos
    International Journal of Molecular Sciences, 2012
    Co-Authors: Lei Tao, Yang Yang, Qiuyu Wang, Xiangling You
    Abstract:

    Dynamic changes in callose content, which is deposited as a plant defense response to physiological changes, were analyzed during somatic embryogenesis in Eleutherococcus senticosus zygotic embryos plasmolyzed in 1.0 M mannitol. During plasmolysis, callose deposition was clearly observed inside the plasma membrane of zygotic embryo epidermal cells using confocal laser scanning microscopy. The callose content of zygotic embryos gradually increased between 0 and 12 h plasmolysis and remained stable after 24 h plasmolysis. During eight weeks induction of somatic embryogenesis, the callose content of explants plasmolyzed for 12 h was slightly higher than explants plasmolyzed for 6 or 24 h, with the largest differences observed after 6 weeks culture, which coincided with the maximum callose content and highest number of globular somatic embryos. The highest frequency of somatic embryo formation was observed in explants plasmolyzed for 12 h. The somatic embryo induction rate and number of somatic embryos per explant were markedly different in zygotic embryos pretreated with plasmolysis alone (78.0%, 43 embryos per explant) and those pretreated with plasmolysis and the callose synthase inhibitor 2-deoxy-d-glucose (11.5%, 8 embryos per explant). This study indicates that callose production is required for somatic embryogenesis in plasmolyzed explants.

  • Callose Deposition Is Required for Somatic Embryogenesis in Plasmolyzed Eleutherococcus senticosus Zygotic Embryos
    2012
    Co-Authors: Lei Tao, Yang Yang, Qiuyu Wang, Xiangling You
    Abstract:

    Abstract: Dynamic changes in callose content, which is deposited as a plant defense response to physiological changes, were analyzed during somatic embryogenesis in Eleutherococcus senticosus zygotic embryos plasmolyzed in 1.0 M mannitol. During plasmolysis, callose deposition was clearly observed inside the plasma membrane of zygotic embryo epidermal cells using confocal laser scanning microscopy. The callose content of zygotic embryos gradually increased between 0 and 12 h plasmolysis and remained stable after 24 h plasmolysis. During eight weeks induction of somatic embryogenesis, the callose content of explants plasmolyzed for 12 h was slightly higher than explants plasmolyzed for 6 or 24 h, with the largest differences observed after 6 weeks culture, which coincided with the maximum callose content and highest number of globular somatic embryos. The highest frequency of somatic embryo formation was observed in explants plasmolyzed for 12 h. The somatic embryo induction rate and number of somatic embryos per explant were markedly different in zygotic embryos pretreated with plasmolysis alone (78.0%, 43 embryos per explant) and those pretreated with plasmolysis and the callose synthase inhibitor 2-deoxy-D-glucose (11.5%, 8 embryos per explant). This study indicates tha

  • plasmolysis treatment enhances the expression of callose synthase gene in zygotic embryos of Eleutherococcus senticosus
    Journal of Forestry Research, 2010
    Co-Authors: Hu Xilin, Dean Xia, Xiangling You
    Abstract:

    In previous study we reported that pretreatment with plasmolysis enhanced somatic embryo formation in hypocotyls of Eleutherococcus senticosus. In the present study, the expression level of callose synthase gene in embryos of E. senticosus in response to 2,4-D, sucrose and mannitol treatments was analyzed by RT-PCR. The results show that plasmolysis pretreatment using sucrose and mannitol significantly promoted the expression of callose synthase gene. Also, the thicker cell walls of explant plasmolyzed compared with controls were observed during the somatic embryogenesis. We suggest that the callose may make the cells in epidermis separate from neighboring cells and then develop into embryogenic potential cells.

  • cellular change and callose accumulation in zygotic embryos of Eleutherococcus senticosus caused by plasmolyzing pretreatment result in high frequency of single cell derived somatic embryogenesis
    Protoplasma, 2006
    Co-Authors: Xiangling You, Yongeui Choi
    Abstract:

    Eleutherococcus senticosus zygotic embryos were pretreated with 1.0 M mannitol or sucrose for 3–24 h. This pretreatment resulted in a high frequency of somatic-embryo formation on hormone-free medium. All the somatic embryos developed directly and independently from single epidermal cells on the surface of zygotic embryos after plasmolyzing pretreatment. Scanning electron microscopic observation revealed that the epidermal cells of hypocotyls rapidly became irregular and showed a random orientation before somatic-embryo development commenced. At the same time, the epidermal cells in the untreated control remained regular. Callose concentration determined by fluorometric analysis increased sharply in E. senticosus zygotic embryos after plasmolyzing pretreatment but remained low in the untreated control. Aniline blue fluorescent staining of callose showed that the plasmolyzing pretreatment of zygotic embryos resulted in heavy accumulation of callose between the plasma membrane and cell walls. On the basis of these results, we suggest that plasmolyzing pretreatment of zygotic embryos induces the accumulation of callose, and the interruption of cell-to-cell communication imposed by this might stimulate the reprogramming of epidermal cells into embryogenically competent cells and finally induce somatic-embryo development from single cells.

Katsuko Komatsu - One of the best experts on this subject based on the ideXlab platform.

  • memory enhancement by oral administration of extract of Eleutherococcus senticosus leaves and active compounds transferred in the brain
    Nutrients, 2019
    Co-Authors: Yui Yamauchi, Kayo Yoshimatsu, Katsuko Komatsu, Tomoharu Kuboyama, Ximeng Yang, Chihiro Tohda
    Abstract:

    The pharmacological properties of Eleutherococcus senticosus leaf have not been clarified although it is taken as a food item. In this study, the effects of water extract of Eleutherococcus senticosus leaves on memory function were investigated in normal mice. Oral administration of the extract for 17 days significantly enhanced object recognition memory. Compounds absorbed in blood and the brain after oral administration of the leaf extract were detected by LC-MS/MS analyses. Primarily detected compounds in plasma and the cerebral cortex were ciwujianoside C3, eleutheroside M, ciwujianoside B, and ciwujianoside A1. Pure compounds except for ciwujianoside A1 were administered orally for 17 days to normal mice. Ciwujianoside C3, eleutheroside M, and ciwujianoside B significantly enhanced object recognition memory. These results demonstrated that oral administration of the leaf extract of E. senticosus enhances memory function, and that active ingredients in the extract, such as ciwujianoside C3, eleutheroside M, and ciwujianoside B, were able to penetrate and work in the brain. Those three compounds as well as the leaf extract had dendrite extension activity against primary cultured cortical neurons. The effect might relate to memory enhancement.

  • ms ms similarity networking accelerated target profiling of triterpene saponins in Eleutherococcus senticosus leaves
    Food Chemistry, 2017
    Co-Authors: Shu Zhu, Kayo Yoshimatsu, Katsuko Komatsu
    Abstract:

    The targeted mass information of compounds accelerated their discovery in a large volume of untargeted MS data. An MS/MS similarity networking is advanced in clustering the structural analogues, which benefits the collection of mass information of similar compounds. The triterpene saponins extracted from Eleutherococcus senticosus leaves (ESL), a kind of functional tea, have shown promise in the relief of Alzheimer's disease. In this work, a target-precursor list (TPL) generated using MS/MS similarity networking was employed to rapidly trace 106 triterpene saponins from the aqueous extracts of ESL, of which 49 were tentatively identified as potentially new triterpene saponins. Moreover, a compound database of triterpene saponins was established and successfully applied to uncover their distribution features in ESL samples collected from different areas.

  • effects of oleanane type triterpene saponins from the leaves of Eleutherococcus senticosus in an axonal outgrowth assay
    Journal of Natural Products, 2016
    Co-Authors: Chihiro Tohda, Kayo Yoshimatsu, Shu Zhu, Katsuko Komatsu
    Abstract:

    An aqueous extract of Eleutherococcus senticosus leaves exerted a beneficial effect in restoring the neurite outgrowth from Aβ25–35-induced degeneration using an axonal density assay. Subsequent bioassay-guided fractionation afforded seven new oleanane-type triterpene saponins, ezoukoginosides A–G (1–7), along with nine known analogues. The structures of 1–7 were elucidated through chemical and spectroscopic approaches, and their effects on restoring the neurite outgrowth from Aβ25–35-induced degeneration were investigated. The results revealed that hydrophilic oleanane-type saponins substituted with a free carboxylic acid, hydroxy, or formyl group in the aglycone, especially when the oxidation occurred at C-29, not only restrained Aβ25–35-induced degeneration but also restored axonal outgrowth significantly. Compounds 2 (−COOH at C-29) and 3 (−CH2OH at C-29) showed the most potent bioactivity among the isolates.

  • Effects of Oleanane-Type Triterpene Saponins from the Leaves of Eleutherococcus senticosus in an Axonal Outgrowth Assay
    2016
    Co-Authors: Chihiro Tohda, Kayo Yoshimatsu, Shu Zhu, Katsuko Komatsu
    Abstract:

    An aqueous extract of Eleutherococcus senticosus leaves exerted a beneficial effect in restoring the neurite outgrowth from Aβ25–35-induced degeneration using an axonal density assay. Subsequent bioassay-guided fractionation afforded seven new oleanane-type triterpene saponins, ezoukoginosides A–G (1–7), along with nine known analogues. The structures of 1–7 were elucidated through chemical and spectroscopic approaches, and their effects on restoring the neurite outgrowth from Aβ25–35-induced degeneration were investigated. The results revealed that hydrophilic oleanane-type saponins substituted with a free carboxylic acid, hydroxy, or formyl group in the aglycone, especially when the oxidation occurred at C-29, not only restrained Aβ25–35-induced degeneration but also restored axonal outgrowth significantly. Compounds 2 (−COOH at C-29) and 3 (−CH2OH at C-29) showed the most potent bioactivity among the isolates

  • genetic and chemical diversity of Eleutherococcus senticosus and molecular identification of siberian ginseng by pcr rflp analysis based on chloroplast trnk intron sequence
    Food Chemistry, 2011
    Co-Authors: Shu Zhu, Katsuko Komatsu, Takuro Maruyama, Takeshi Kawasaki, Masao Fujita, Yukihiro Goda, Yanjing Bai, Mayuko Oya, Ken Tanaka, Toshiro Shibata
    Abstract:

    Abstract Siberian ginseng (SG), the rhizome and root of Eleutherococcus senticosus , has been used as a tonic and anti-fatigue agent in northeastern Asia from ancient time. In recent years, SG has been becoming fairly popular as dietary supplements and health foods worldwide. In order to establish a convenient and sensitive method for authentication, chloroplast trn K intron sequences of 6 Eleutherococcus species were determined and compared. Genetic polymorphism, representing by 14 types of trn K intron sequence, in E. senticosus was observed. However, characteristic nucleotide markers stable within this species enabled clear discrimination of it from other congeners. A PCR-RFLP method was further developed, which was demonstrated to be efficient for authentication of crude drugs as well as health foods. Quantitative evaluation of three main bioactive constituents indicated chemical diversity in E. senticosus collected from northeast China and the results suggested good producing areas of SG. The chemical data clearly revealed that E. sessliflorus was unsuitable to be used as SG.

A M Shohael - One of the best experts on this subject based on the ideXlab platform.

Keeyoeup Paek - One of the best experts on this subject based on the ideXlab platform.

  • a comprehensive in silico exploration of pharmacological properties bioactivities and cox 2 inhibitory potential of eleutheroside b from Eleutherococcus senticosus rupr maxim maxim
    Journal of Biomolecular Structure & Dynamics, 2020
    Co-Authors: Sium Ahmed, Dil Afroj Moni, Kailas Dashrath Sonawane, Keeyoeup Paek, A M Shohael
    Abstract:

    Eleutherococcus senticosus (Rupr. & Maxim.) Maxim., popularly known as ‘Siberian ginseng’, is an important medicinal plant. Pharmacologically active compounds of this plant are called eleutheroside...

  • pilot scale culture of somatic embryos of Eleutherococcus senticosus in airlift bioreactors for the production of eleutherosides
    Biotechnology Letters, 2014
    Co-Authors: A M Shohael, Hosakatte Niranjana Murthy, Keeyoeup Paek
    Abstract:

    Purpose of work To establish pilot scale bioreactor cultures of somatic embryos of Siberian ginseng for the production of biomass and eleutherosides. Somatic embryos of Eleutherococcus senticosus were cultured in airlift bioreactors using Murashige and Skoog medium with 30 g sucrose l−1 for the production of biomass and eleutherosides. Various parameters including the type of bioreactor, aeration volume, and inoculum density were optimized for 3 l capacity bioreactors. Balloon-type airlift bioreactors, utilizing a variable aeration volume of 0.1–0.3 vvm and an inoculum of 5 g l−1, were suitable for biomass and eleutheroside production. In 500 l balloon-type airlift bioreactors, 11.3 g dry biomass l−1, 220 µg eleutheroside B l−1, 413 µg eleutheroside E l−1, and 262 µg eleutheroside E1 l−1 were produced.

  • methyl jasmonate induced overproduction of eleutherosides in somatic embryos of Eleutherococcus senticosus cultured in bioreactors
    Electronic Journal of Biotechnology, 2007
    Co-Authors: A M Shohael, Hosakatte Niranjana Murthy, Eunjoo Hahn, Keeyoeup Paek
    Abstract:

    This study was concentrated on the production of eleutherosides and chlorogenic acid in embryogenic suspension cultures of Eleutherococcus senticosus by exposing them to different concentrations (50-400 µM) of methyl jasmonate (MJ) during the culture period. In the bioreactor cultures, eleutheroside content increased significantly by elicitation of MJ, however, the fresh weight, dry weight and growth ratio of embryos was strongly inhibited by increasing MJ concentrations. The highest total eleutheroside (7.3 fold increment) and chlorogenic acid (3.9 fold increment) yield was obtained with 200 µM MJ treatment. There was 1.4, 3.4 and 14.9 fold increase in the eleutheroside B, E, and E1 production respectively with such elicitation treatment. These results suggest that MJ elicitation is beneficial for eleutheroside accumulation in the embryogenic cell suspension cultures.

  • effect of light on oxidative stress secondary metabolites and induction of antioxidant enzymes in Eleutherococcus senticosus somatic embryos in bioreactor
    Process Biochemistry, 2006
    Co-Authors: A M Shohael, Eunjoo Hahn, Keewon Yu, R Islam, Keeyoeup Paek
    Abstract:

    Abstract Eleutherococcus senticosus somatic embryos were cultured in Murashiage and Skoog medium in balloon type bubble bioreactor (working volume 2-l) to investigate the effect of light on biomass, secondary metabolites, stress levels (lipid peroxidation and hydrogen peroxide (H2O2) and changes of antioxidant enzymes. Among the different light sources, biomass accumulation was found optimum under fluorescent (Fl) and mixed blue plus far-red (Bl + Fr) irradiation. Accumulation of eleutheroside E (51%) and E1 (21%) was highest at red light while fluorescent light produced highest amount of total phenolic (2.7%), total flavonoid (34%) and chlorogenic acid (14%) contents compared to dark (control) grown mature embryos. Higher H2O2 content, malondialdehyde (MDA) content and lipoxygenase (LOX) activities was observed at red light treated embryos compared to dark (control) grown embryos. Antioxidant enzymes, monodehydroascorbate reductase (MDHAR), catalase (CAT), glutathione S transferase (GST) and superoxide dismutase (SOD) which are playing important role for the detoxification of harmful substances were also induced in red light irradiated embryos. However, ascorbate peroxidase (APX) took a little part in detoxification of H2O2 due to its sensitivity to red light. Therefore, reduced APX activity in red light treated embryos was observed. While APX activity was maximum in fluorescent light treated embryos compared to other light sources. This reflects the sensitivity of the enzyme to the different light. The study concludes that embryo could grow under different light irradiation and protect themselves from toxicity of light sources by altering various phenolic compounds and antioxidant enzymes.

  • effect of temperature on secondary metabolites production and antioxidant enzyme activities in Eleutherococcus senticosus somatic embryos
    Plant Cell Tissue and Organ Culture, 2006
    Co-Authors: A M Shohael, Eunjoo Hahn, Keewon Yu, Keeyoeup Paek
    Abstract:

    Somatic embryos of Eleutherococcus senticosus were exposed at 12, 16, 24 and 30 °C for duration of 45 days in bioreactor. The effects of such treatments on the growth, eleutheroside B, E, E1, total phenolics, flavonoids, chlorogenic acid concentrations and antioxidant enzymes activities were investigated. The results revealed that low (12 and 18 °C) and high (30 °C) temperature caused significant decrease in fresh weight (FW), dry weight (DW), total phenolics, flavonoids and total eleutheroside accumulation, while low temperature increased eleutheroside E accumulation in somatic embryos. Low temperature significantly increased superoxide dismutase (SOD), catalase (CAT), dehydroascorbate reductase (DHAR) and glutathione reductase (GR) activities whereas a strong increase in ascorbate peroxidase (APX) and monodehydroascorbate reductase (MDHAR) activity was obtained at 12 °C grown somatic embryos. In contrast, high temperature significantly decreased antioxidant enzymes activities and even guaiacol peroxidase (G-POD) activity also decreased at low temperature in comparison to 24 °C grown embryos. These data suggest that low and high temperature treatment provoked an oxidative stress in E. senticosus embryos, as shown by the increase in lipid peroxidation. The increase in lipid peroxidation was paralleled by a rise in lipoxygenase (LOX) activity and hydrogen peroxide (H2O2) content. However, this stress was more prominent at high temperature than low temperature grown embryos. This result suggests that the reduced growth of embryo at 30 °C was concomitant with reduced efficiency of these protective enzymes. On the other hand, increases in antioxidant activities at 12 and 18 °C could also be a response to the cellular damage; however, this increase could not stop the deleterious effects of low temperature, but reduced stress severity thus allowing embryo growth to occur.