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Twonew heterodimeric sesquiterpenes, sterhirsutins A (1)and B (2), and two new sesquiterpenes, hirsutic acidsD–E (3and 4), were identified fromthe culture of Stereum hirsutum. The absolute configurationsin 1and 2were confirmed by single-crystalX-ray diffraction experiments and electronic circular dichroism (ECD)calculations. Compounds 1and 2are likelybiosynthesized from a hirsutane-type sesquiterpene and α-humuleneby a hetero-Diels–Alder cycloaddition. Compounds 1–4showed cytotoxicity against K562 and HCT116cell lines. [ABSTRACT FROM AUTHOR]

Four new ambuic acid derivatives (1-4), and four known derivatives (5-8), were isolated from the solid culture of a plant pathogenic fungus Pestalotiopsis neglecta. Their structures were elucidated by extensive NMR experiments. The absolute configuration of the C-16 secondary alcohol in 1 was deduced via the CD data of the in situ formed [Rh2(OCOCF3)4] complex with the acetonide derivative of 1. The absolute configuration in 3 was assigned by comparison of the experimental and simulated electronic circular dichroism (ECD) spectrum. The NMR data of compound 5 was reported for the first time. In the nitric oxide (NO) inhibition assay, compounds 4, 6 and 7 showed inhibitory activity against the NO production in the lipopolysaccharide (LPS)-induced macrophage with IC50 values of 88.66, 11.20, and 20.80 µM, respectively. [ABSTRACT FROM AUTHOR]

Coicenals A–C (1–3) possessing a previously undescribed 10-(sec-butyl)-6-hydroxy-1,7,9-trimethyl-1,6,7,8,9,9a-hexahydro-1,4-methanobenzo[d]oxepin-2(4H)-ylidene)acetaldehyde skeleton and coicenal D (4) with a new 2-(sec-butyl)-5-hydroxy-1,6,8-trimethyl-2,5,6,7,8,8a-hexahydro-1H-4a,1-(epoxymethano)naphthalen-10-ylidene)acetaldehyde skeleton were isolated from the solid culture of the plant pathogenic fungus Bipolaris coicis. The absolute configurations in 1and 4were assigned by electronic circular dichroism (ECD) calculations. Compounds 1and 2were transformed into 4and 5by treatment with acetyl chloride, respectively. Compounds 1–4showed moderate inhibitory activity against NO release with IC50values of 16.34 ± 1.12, 23.55 ± 1.37, 10.82 ± 0.83, and 54.20 ± 2.82 μM, respectively. [ABSTRACT FROM AUTHOR]