Five sesquiterpene-based meroterpenoids with three kinds of new skeletons [1, 2, 3, (+)-4, and (-)-4] were isolated from the leaves of Myrtus communis. Compound 1 featured a new carbon skeleton with an unprecedented octahydrospiro[bicyclo[7.2.0]undecane-2,2'-chromene] tetracyclic ring system, which possessed two preferred conformations detected by variable-temperature NMR spectroscopy experiments. In addition, the structure of reported myrtucommulone K was revised to be compound 3. The plausible biosynthetic pathways of these meroterpenoids and their cytotoxicities are discussed.
Catalytic hydrogenation of 21-deoxyajmalal-A3 and 2-hydroxyvincamedine under acidic conditions proceeded from the a side of the compounds to yield 2-epi series of ajmaline type compounds [J.
Four new Amaryllidaceae alkaloids, named lycoranines C-F (1-4), together with seven known ones (5-11) were isolated from the bulbs of Lycoris radiata. Their structures with absolute configurations were elucidated by nuclear magnetic resonance, high-resolution electrospray ionization mass spectrometry, circular dichroism spectra, modified Mosher's method, and molecular modeling calculation. Compounds 6, 7, 10, and 11 exhibited a potent inhibitory effect on A549 and LoVo cells with IC50 values ranging from 3.97 ± 0.36 to 17.37 ± 1.57 µM.
Six rearranged sesquiterpenoid dimers and monomers with four kinds of new skeletons, meso-eugenunilone A (meso-1), (+)- and (-)-eugenunilones B-F [(+)-and (-)-2-6], along with two new biogenetically related members (+)- and...
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