Unexpected Noremestrin with a Sulfur-Bearing 15-Membered Macrocyclic Lactone from Emericella sp. 1454

Abstract

Two previous unreported epipolythiodioxopiperazines of the emestrin family, namely, noremestrin A (1) and secoemestrin E (2), were successfully isolated from the fungal source Emericella sp. 1454. Employing comprehensive spectroscopic techniques, such as high-resolution electrospray ionization mass spectrometry, infrared, and nuclear magnetic resonance (NMR), along with NMR and electronic circular dichroism calculations, the chemical structures of compounds 1 and 2 were elucidated. Particularly noteworthy is the distinctive nature of noremestrin A, representing the inaugural instance of a noremestrin variant incorporating a sulfur-bearing 15-membered macrocyclic lactone moiety. Compounds 1 and 2 exhibited weak cytotoxic activities against the human chronic myelocytic leukemia cell lines MEG-01 and K562.

Purification, characterization and study of blue fluorescent substance in caffeine

“…The MS data showed that there was [M + H] + ion at m/z 253.0894. The 13 C NMR, 1 H NMR, homonuclrar correlation spectroscopy (COSY), nuclear overhauser effect spectroscopy (NOESY),heteronuclear single‐quantum correlation (HSQC) and heteronuclear multiple‐bond correlation (HMBC) 34 of the blue fluorescent substance are shown in Figs 6–11, respectively, and the obtained data are shown in Table 4.…”

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“…1454, has an unusual sulfur-bearing 15-membered macrocylic lactone. 8 The structure of asperinamide A 8 , from Aspergillus sp. TE-65L, was confirmed by X-ray analysis.…”