• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.12a
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• pp.16-44
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• 2020

Cancer is the second leading cause of death in the world. According to the 2018 reports, one in six people worldwide is reported to die as a result of cancer. The discovery of anticancer drugs has been utilized extensively, but there has been no report on excellent selective activity in cancer cells. The discovery of bioactive substances from marine sponges has been the limelight in the pharmaceutical field over the past decade owing to the production of many bioactive compounds from the sponges to protect themselves against the environment. On top of that, marine sponges also produced cytotoxic compounds such as terpenoids, alkaloids, steroids, and peptides which suggests that marine sponges have high potential in the development of anticancer drugs. Thus, this study aimed to obtain new cytotoxic compounds from S. siphonella in Egypt and Arenoscelra sp. and Gelliodes sp. in Vietnam, and further investigation of the extract from these marine sponges led to isolation of ten new compounds and 21 known compounds. Chapter 1 will discuss about the isolation and structure elucidation of eight new polyacetylene derivatives from S. siphonella and their cytotoxic activities. The isolation and structural elucidation of one new polybrominated iododiphenyl ether from Arenosoclea sp. as well as cytotoxic activities of the isolated compounds will be reported in chapter 2. Finally, isolation and structure elucidation of new compounds from the marine sponge Gelliodes sp. and their cytotoxic activities will be discussed in chapter 3.

• Journal of Applied Biological Chemistry
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• v.42 no.4
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• pp.205-207
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• 1999

• Journal of Microbiology
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• v.44 no.4
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• pp.432-438
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• 2006

Twelve actinomycete strains were isolated from Egyptian soil. The isolated actinomycete strains were then screened with regard to their potential to generate antibiotics. The most potent of the producer strains was selected and identified. The cultural and physiological characteristics of the strain identified. the strain as a member of the genus Streptomyces. The nucleotide sequence of the 16S rRNA gene (1.5kb) of the most potent strain evidenced a 99% similarity with Streptomyces spp. and S. aureofaciens 16S rRNA genes, and the isolated strain was ultimately identified as Streptomyces sp. MAR01. The extraction of the fermentation broth of this strain resulted in the isolation of one major compound, which was active in vitro against gram-positive, gram-negative representatives and Candida albicans. The chemical structure of this bioactive compound was elucidated based on the spectroscopic data obtained from the application of MS, IR, UV, $^1H$ NMR, $^{13}C$ NMR, and elemental analysis techniques. Via comparison to the reference data in the relevant literature and in the database search, this antibiotic, which had a molecular formula of $C_{19}H_{29}NO_2$ and a molecular weight of 303.44, was determined to differ from those produced by this genus as well as the available known antibiotics. Therefore, this antibiotic was designated Meroparamycin.

• Korean Journal Plant Pathology
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• v.12 no.3
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• pp.302-306
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• 1996

항균물질을 생산하는 방선균 KGT-37를 인삼밭 토양에서 분리하여 배양액으로부터 항균물질을 분리하고 silica gel column chromatography, preparative TLC, HPLC로 정제하였다. \ulcornerH-\ulcornerH COSY, HMQC, HMBC등 NMR 분석결과 KGT-37이 생산하는 항균물질은 cyclic depsipeptide계의 항생물질인 echinomycin으로 동정되었으며 이 연구에서 지금까지 assign되지 않았던 \ulcornerH과\ulcornerC의 NMR signal이 완전히 assign되었다. 이 항균활성물질은 감자더뎅이병균인 Streptomyces scabies과 Corynebacterium lilium을 포함하는 그람 양성 세균에 특히 강한 항균활성을 보였으며, 도열병균 및 점무늬낙엽병균 등 병원곰팡이에도 항균활성을 나타내었다.

• Journal of the Korean Magnetic Resonance Society
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• v.28 no.3
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• pp.25-31
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• 2024

Toxins produced by marine toxigenic algae have garnered growing attention due to their detrimental impacts on marine ecosystem, aquaculture, and human health. Among these, diarrhetic shellfish poisoning (DSP) toxins, such as okadaic acid (OA), are of particular concern. In this study, we report the successful isolation and structural elucidation of three new derivatives of OA from the marine dinoflagellate Prorocentrum lima. These newly identified compounds, OA-2Me-C7, OA-2-Me-C8, and OA-1-Me-C8, were characterized through a comprehensive series of NMR experiments, combined with structural comparisons to the well-known OA. The identification of these derivatives contributes to the expanding knowledge of DSP toxin diversity and provides new insights into the structural variations of these harmful algal toxins.

• Proceedings of the Korean Biophysical Society Conference
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• 1998.06a
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• pp.21-21
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• 1998

Since the repair efficiency of non-Watson-Crick base pairs in DNA is affected by the mismatched base-pairs and their neighbor sequences, the structural studies are necessary for the elucidation of the repair efficiency. NMR and molecular modeling studies on the DNA duplexes including AA mismatches were performed.(omitted)

• YAKHAK HOEJI
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• v.30 no.4
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• pp.198-201
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• 1986

The successful elucidation of the opiate receptor and its natural ligands has generated speculation that other drugs might interact with cellular sites designed to accommodate endogenous mediators. The properties of binding sites for the cardiac glycosides(CG), together wit the potency and specificity of the digitalis drugs suggest that CG mimic an endogenous digitalis-like factor. Recenthy, several laboratories have reported the potency in mammalian tissues and fluids of unidentified materials that share certain specific propeties of the CG. Identification of body's own digitalis might yield a natural co pound whose synthetic analogs may provide safer and more effective drugs than can be achieved by structural edification of the CG of plant origin.

• The Korean Journal of Food And Nutrition
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• v.13 no.3
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• pp.269-272
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• 2000

Penaeus orientalis 껍질에서 6종류의 carotenoids가 분리정제되었다. $\beta$-carotene(3.1%), doradexanhinester(6.1%), astaxanthin diester(54.8%), zeaxan-thin monoester(7.9%), astaxanthin monoester(12.4%) 그리고 astaxanthin(5.7%)의 함량과 구조들은 UV/VIS.IR $^1$H0NMR. MS 스펙트라와 검화반응, 아세탈화반응, 알릴릭그룹,에폭시 반응 그리고 환원반응을이용하여 결정되었다. Carotenoids와 에스테르 결합된 지방산들은 주로 $C_{18:1}$, $C_{16:0}$, $C_{16:1}$ 이고 나머지 지방산들도 소량 함유되었다.되었다.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.52-55
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• 1998

During a survey of new antitumor substances from higher plants, we have found that the crude extract of Simaba cedron Planchon (Simaroubaceae) showed cytotoxic activity (IC$\sub$50/ 0.7 $\mu\textrm{g}$/mL) against P388 leukemia cells. Activity-guided chromatographic purification using P388 cells led to the isolation of five novel quassinoids, cedronolactones A-E (1-5) and nine known quassinoids, simalikalactone D (6), chaparrinon (7), chaparrin (8), glaucarubolone (9), glaucarubol (10), samaderine Z (11), guanepolide (12), ailanquassin A (13), and polyandrol (14). In this seminar, the structural elucidation of 1-5 and the cytotoxic activity of the isolated compounds are discussed.

• Proceedings of the Zoological Society Korea Conference
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• 2000.10a
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• pp.229.1-229
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• 2000

No Abstract, See Full Text