Dimeric tetrahydroxanthones from the lichen Usnea aciculifera
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Chemical Dimerization-Induced Protein Condensates on Telomeres
Published on: April 12, 2021
Truong L Tuong1, Thammarat Aree1, Lien T M Do2
1Center of Excellence in Natural Products Chemistry, Department of Chemistry, Faculty of Science, Chulalongkorn University, Phayathai Road, Patumwan, Bangkok 10330, Thailand.
Abstract:
Four unusual heterodimeric tetrahydroxanthones, usneaxanthones A-D (1-4) were isolated from lichen Usnea aciculifera Vain (Parmeliaceae). Their structures and absolute configurations, particularly the central and axial chiralities, were unambiguously demonstrated by a combination of spectroscopic data (1D, 2D NMR, HRESIMS), electronic circular dichroism (ECD) experiments, and single-crystal X-ray crystallographic analyses. Cytotoxic effects of isolated compounds (1, 2 and 4) were evaluated on HT-29 human colorectal cancer cells. Compound 4 showed potent cytotoxicity against HT-29 with IC50 values of 2.41 μM.
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