Metabolites of the Mangrove Fungus Xylaria sp. BL321 from the South China Sea

Abstract

Two new lactones, 1 and 2, together with five known compounds, 3–7, were isolated from the marine mangrove fungus Xylaria sp. BL321. Their structures were determined by comprehensive analysis of their MS and NMR spectroscopic data. The absolute configurations of 1 and 2 were established on the basis of electronic circular dichroism calculations. It was found that the exocyclic double bond of 1 rearranged into a cyclic double bond to form a new crystal compound (1a) in diluted NaOH solution. Compound 3 was isolated for the first time as a natural product; its absolute configuration was determined by single-crystal X-ray crystallography. Compounds 4–7 displayed cytotoxicity against human breast cancer cell lines MCF-7 and MDA-MB-435, while compounds 1–3 were inactive (IC₅₀ > 50 µM).

Key words

Xylaria sp. - Acanthus ilicifolius L. - Acanthaceae - mangrove fungus - lactone - electronic circular dichroism

References

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