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Song, Dahae,Bae, Jinhee,Ji, Hoon,Kim, Min-Bum,Bae, Youn-Sang,Park, Kyo Sung,Moon, Dohyun,Jeong, Nak Cheon American Chemical Society 2019 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.141 No.19
<P>Enhancement of hydrolytic stability of metal-organic frameworks (MOFs) is a challenging issue in MOF chemistry because most MOFs have shown limitations in their applications under a humid environment. Meanwhile, inner sphere electron transfer has constituted one of the most intensively studied subjects in contemporary chemistry. In this report, we show, for the first time, a new conceptual <I>coordinative reduction</I> of Cu<SUP>2+</SUP> ion, which is realized in a paddlewheel MOF, HKUST-1, with a postsynthetic manner via inner sphere “single” electron transfer from hydroquinone (H<SUB>2</SUB>Q) to Cu<SUP>2+</SUP> through its coordination bond. H<SUB>2</SUB>Q treatment of HKUST-1 under anhydrous conditions leads to the single charge (1+) reduction of approximately 30% of Cu<SUP>2+</SUP> ions. Thus, this coordinative reduction is an excellent reduction process to be self-controlled in both oxidation state and quantity. As described below, once Cu<SUP>2+</SUP> ions are reduced to Cu<SUP>+</SUP>, the reduction reaction does not proceed further, in terms of their oxidation state as well as their amount. Also, we demonstrate that a half of the Cu<SUP>+</SUP> ions (about 15%) remains in paddlewheel framework with pseudo square planar geometry and the other half of the Cu<SUP>+</SUP> ions (about 15%) forms [Cu(MeCN)<SUB>4</SUB>]<SUP>+</SUP> complex in a small cage in the fashion of a ship-in-a-bottle after dissociation from the framework. Furthermore, we show that the coordinative reduction results in substantial enhancement of the hydrolytic stability of HKUST-1 to the extent that its structure remains intact even after exposure to humid air for two years.</P> [FIG OMISSION]</BR>
Neuroprotective Compound from an Endophytic Fungus, <i>Colletotrichum</i> sp. JS-0367
Song, Ji Hoon,Lee, Changyeol,Lee, Dahae,Kim, Soonok,Bang, Sunghee,Shin, Myoung-Sook,Lee, Jun,Kang, Ki Sung,Shim, Sang Hee American Chemical Society and American Society of 2018 Journal of natural products Vol.81 No.6
<P><I>Colletotrichum</I> sp. JS-0367 was isolated from <I>Morus alba</I> (mulberry), identified, and cultured on a large scale for chemical investigation. One new anthraquinone (<B>1</B>) and three known anthraquinones (<B>2</B>-<B>4</B>) were isolated and identified using spectroscopic methods including 1D/2D-NMR and HRESIMS. Although the neuroprotective effects of some anthraquinones have been reported, the biological activities of the four anthraquinones isolated in this study have not been reported. Therefore, the neuroprotective effects of these compounds were determined against murine hippocampal HT22 cell death induced by glutamate. Compound <B>4</B>, evariquinone, showed strong protective effects against HT22 cell death induced by glutamate by the inhibition of intracellular ROS accumulation and Ca<SUP>2+</SUP> influx triggered by glutamate. Immunoblot analysis revealed that compound <B>4</B> reduced the phosphorylation of MAPKs (JNK, ERK1/2, and p38) induced by glutamate. Furthermore, compound <B>4</B> strongly attenuated glutamate-mediated apoptotic cell death.</P> [FIG OMISSION]</BR>
Bang, Sunghee,Song, Ji Hoon,Lee, Dahae,Lee, Changyeol,Kim, Soonok,Kang, Ki Sung,Lee, Jong Hun,Shim, Sang Hee American Chemical Society 2019 Journal of agricultural and food chemistry Vol.67 No.7
<P>Roots of <I>Glehnia littoralis</I> have been used to heal stroke as a traditional medicine. Even though many studies on this plant have been conducted, the secondary metabolites produced by its endophytes and their bioactivities have not been investigated thus far. Therefore, a new meroditerpenoid named sartorypyrone E (<B>1</B>) and eight known compounds (<B>2</B>-<B>9</B>) were isolated from extracts of cultured <I>Neosartorya fischeri</I> JS0553, an endophyte of <I>G. littoralis</I>. The isolated metabolites were identified using spectroscopic methods and chemical reaction, based on a comparison to literature data. Relative and absolute stereochemistries of compound <B>1</B> were also elucidated. To identify the protective effects of isolated compounds (<B>1</B>-<B>9</B>) in HT22 cells against glutamate-induced cytotoxicity, we assessed inhibition of cell death, intracellular reactive oxygen species (ROS) accumulation, and calcium ion (Ca<SUP>2+</SUP>) influx. Among the isolates, compound <B>8</B>, identified as fischerin, showed significant neuroprotective activity on glutamate-mediated HT22 cell death through inhibition of ROS, Ca<SUP>2+</SUP> influx, and phosphorylation of mitogen-activated protein kinase, including c-Jun N-terminal kinase, extracellular signal-regulated kinase, and p38. The results suggested that the metabolites produced by the endophyte <I>N. fischeri</I> JS0553 might be related to the neuroprotective activity of its host plant, <I>G. littoralis</I>.</P> [FIG OMISSION]</BR>