Design and Synthesis of Novel Lamellarin D Analogues Targeting Topoisomerase I

ナノダイナミクス国際シンポジウム 平成22年1月21日(木) 於長崎大学Nagasaki Symposium on Nano-Dynamics 2010 (NSND2010), January 21, 2010, Nagasaki University, Nagasaki, Japan, Invited Lectur

Efficient Total Syntheses of Heterocyclic Marine Alkaloids, Lamellarins

Nagasaki Symposium on Nano-Dynamics 2008 (NSND2008) 平成20年1月29日(火)於長崎大学 Poster Presentatio

A formal total synthesis of the telomerase inhibitor dictyodendrin B

A formal synthesis of the telomerase inhibitory marine pyrrolocarbazole alkaloid dictyodendrin B is described. The key features are consecutive palladium-catalyzed cross-coupling reactions and intramolecular reductive coupling reaction to construct the pyrrolo[2,3-c]carbazole framework

Total synthesis of the marine natural products lukianols A and B

Total synthesis of the pyrrolic marine natural products lukianols A (1) and B (2) has been achieved using N-benzenesulfonyl-3,4-dibromopyrrole (3) as a common starting material. The key synthetic strategy developed is the combined bromine-directed lithiation and palladium-catalyzed cross-coupling of 3 to produce 3,4-diarylpyrrol-2-carboxylates. Regioselective iodination of the phenolic intermediate 24 was thoroughly investigated for the synthesis of lukianol B

Dynamic Trend of Myocardial Edema in Takotsubo Syndrome: A Serial Cardiac Magnetic Resonance Study

BACKGROUND The wall motion abnormalities of the left ventricle (LV) in takotsubo syndrome (TTS) are known to be transient and completely recover within a few weeks. However, there is little information about the relationship between functional recovery and tissue characteristics. The aim of this study was to investigate the recovery process of TTS using cardiovascular magnetic resonance (CMR). METHODS Consecutive patients with TTS were prospectively enrolled. We performed serial CMR in the acute phase (<72 h after admission), the subacute phase (7-10 days after admission) and the chronic phase (3 months later). To assess the degree of myocardial edema quantitatively, we evaluated the signal intensity of myocardium on T2-weighted images and calculated the signal intensity ratio compared with the skeletal muscle. RESULTS Fifteen patients with TTS were enrolled. CMR demonstrated reduced LV ejection fraction in the acute phase, and it recovered almost completely by the subacute phase. On the other hand, severe myocardial edema was still observed in the subacute phase, associated with increased LV mass. The highest signal intensity ratio in the subacute phase was correlated with the maximum voltage of negative T wave on electrocardiogram (r = 0.57, p = 0.03). CONCLUSIONS In patients with TTS, myocardial edema associated with increased LV mass still remained in the subacute phase despite functional recovery of the LV. Electrocardiogram may be useful to assess the degree of myocardial edema in the subacute phase. Our study suggests that myocardial ischemia might have a central role in developing TTS

Intermolecular cycloaddition of ethyl glyoxylate O-tert- butyldimethylsilyloxime with alkenes

金沢大学大学院自然科学研究科生理活性物質科学金沢大学薬学部Ethyl glyoxylate O-tert-butyldimethylsilyloxime, on treatment with various alkenes in the presence of BF3·OEt2, generated a C-ethoxycarbonyl N-boranonitrone intermediate, which underwent intermolecular cycloaddition to afford 3-(ethoxycarbonyl)isoxazolidines in moderate to high yields. © Georg Thieme Verlag Stuttgart

Unique Mode of Antiviral Action of a Marine Alkaloid against Ebola Virus and SARS-CoV-2

Lamellarin α20-sulfate is a cell-impenetrable marine alkaloid that can suppress infection that is mediated by the envelope glycoprotein of human immunodeficiency virus type 1. We explored the antiviral action and mechanisms of this alkaloid against emerging enveloped RNA viruses that use endocytosis for infection. The alkaloid inhibited the infection of retroviral vectors that had been pseudotyped with the envelope glycoprotein of Ebola virus and SARS-CoV-2. The antiviral effects of lamellarin were independent of the retrovirus Gag-Pol proteins. Interestingly, although heparin and dextran sulfate suppressed the cell attachment of vector particles, lamellarin did not. In silico structural analyses of the trimeric glycoprotein of the Ebola virus disclosed that the principal lamellarin-binding site is confined to a previously unappreciated cavity near the NPC1-binding site and fusion loop, whereas those for heparin and dextran sulfate were dispersed across the attachment and fusion subunits of the glycoproteins. Notably, lamellarin binding to this cavity was augmented under conditions where the pH was 5.0. These results suggest that the final action of the alkaloid against Ebola virus is specific to events following endocytosis, possibly during conformational glycoprotein changes in the acidic environment of endosomes. Our findings highlight the unique biological and physicochemical features of lamellarin α20-sulfate and should lead to the further use of broadly reactive antivirals to explore the structural mechanisms of virus replication