One new neolignan, racelactone A (1), together with seven known compounds (2−8) were isolated from the methanolic extract of the leaves and twigs of Lumnitzera racemosa. The structure of racelactone A (1) was determined on the basis of the mass and NMR spectroscopic data interpretation. With respect to bioactivity, compound 1 displayed an anti-angiogenic effect by suppressing tube formation. Furthermore, compounds 1, 4, and 5 showed significant anti-inflammatory effects with IC50 values of 4.95 ± 0.89, 1.95 ± 0.40, and 2.57 ± 0.23 μM, respectively. The plausible biosynthesis pathway of racelactone A (1) was proposed.
Three new compounds, tuberazines A–C (1–3), and eleven known compounds (4–14) were obtained from the ethanolic extract of Taiwanese zoanthid Palythoa tuberculosa. Compounds 1–4 are rare marine natural products with a pyrazine moiety, and compound 5 is a tricyclic tryptamine derivative isolated from nature for the first time. The structures of all isolated metabolites were determined by analyzing their IR, Mass, NMR, and UV spectrometric data. The absolute configuration of 1 was confirmed by comparing the trend of experimental electronic circular dichroism (ECD) with calculated ECD spectra. The anti-lymphangiogenic activities of new compounds were evaluated in human lymphatic endothelial cells (LECs). Of these, new compound 3 displayed the most potent anti-lymphangiogenesis property by suppressing cell growth and tube formation of LECs.
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