A rhodamine‐triazole fluorescent chemodosimeter for Cu2+ detection and its application in bioimaging

A rhodamine‐based fluorescent chemodosimeter rhodamine hydrazide‐triazole (RHT) tethered with a triazole moiety was developed for Cu²⁺ detection. In aqueous medium, the RHT probe exhibited high selectivity and sensitivity toward Cu²⁺ among other metal ions. The addition of Cu²⁺ triggered a fluorescence emission of RHT by 384‐fold (Φ = 0.33) based on a ring‐opening process and a subsequent hydrolysis reaction. Moreover, RHT also showed a selective colorimetric response toward Cu²⁺ from colorless solution to pink, readily observed with the naked eye. The limit of detection of RHT for Cu²⁺ was calculated to be 1 nM (0.06 ppb). RHT was successfully demonstrated to detect Cu²⁺ in Chang liver cells by confocal fluorescence microscopy.     

Antiplasmodial and antimycobacterial cyclopeptide alkaloids from the root of Ziziphus mauritiana

Investigation of the MeOH extract obtained from the root of the Ziziphus mauritiana grown in Thailand resulted in the isolation of two 14- and 13-membered cyclic alkaloids, mauritine L (1) and mauritine M (2), and three known cyclopeptide alkaloids, nummularines H (3), B (4) and hemsine A (5). Their structures were elucidated on the basis of extensive NMR spectroscopic analysis. The first single crystal X-ray diffraction study of the 13-membered ring cyclopeptide, nummularine B methiodide (4′), revealed all S configurations on the amino acid residues. The isolated alkaloids exhibited potent antiplasmodial activity against the parasite Plasmodium falciparum with the inhibitory concentration (IC₅₀) ranging from 3.7 to 10.3 μM. Compounds 2 and 3 also demonstrated antimycobacterial activity against Mycobacterium tuberculosis with the MIC of 72.8 and 4.5 μM, respectively.     

Novel spiro-sesquiterpene from the mushroom Anthracophyllum sp. BCC18695

A novel spiro-sesquiterpene, anthracophyllic acid (1), and a new aristolane sesquiterpene, anthracophyllone (2), were isolated from the mushroom Anthracophyllum sp. BCC18695, together with seven known compounds including aurisins A (3), G (4), K (5), nambinones A, C, axinysones A, and B. The relative configuration of 1 and the hitherto unknown absolute stereochemistry of 3 were determined based on X-ray spectroscopic data. Biological activities including antimalarial activity against Plasmodium falciparum K1 strain, antibacterial property against Bacillus cereus, and cytotoxicity against MCF-7, KB, NCI-H187, and Vero cells of the isolated compounds were also evaluated