Chemical examination of two marine Streptomycetes has resulted in the isolation of four new butenolides, namely 4,10-dihydroxy-10-methyl-dodec-2-en-1,4-olide (1), two diastereomeric 4,11-dihydroxy-10-methyldodec-2-en-1,4-olides (2/3), and 4-hydroxy-10-methyl-11-oxo-dodec-2-en-1,4-olide (4). The structures were identified by interpretation of the 2D NMR and mass spectral data.Butenolides, a family of R, -unsaturated lactones, are often encountered among fungi, 2 bacteria, 3 and gorgonians, 4 to name a few. Their saturated analogues act as signaling substances in bacteria 5 and enhance spore formation of Streptomycetes or induce metabolite production. 6 In a continuing search for bioactive constituents from marine microorganisms, we found that extracts from the Streptomycete strains B 5632 and B 3497 from marine sediments formed several new butenolides.The isolate B 5632 was fermented in a 20-L scale on YMG medium with artificial seawater for 3 days. The fermentation broth was filtered over Celite and exhaustively extracted with ethyl acetate. This extract was partitioned between methanol and cyclohexane for defatting, and the methanol layer, after concentration, was chromatographed on a flash column. Bioassay-guided fractionation led to the localization of the activity from which four known antimycins and three new butenolides (1-3) were obtained. In a similar way, strain B 3497 delivered a new keto butenolide (4) in addition to antimycin A. The antimycins were responsible for the strong antifungal activity of the extracts against Mucor miehei (Tü 284).Analytical HPLC indicated that the butenolide fraction (localized by a strong blue-violet color on spraying with anisaldehyde) contained two related compounds. Compound 1 was obtained as an oil by preparative HPLC. Under EIMS conditions, no molecular ion was visible; however, its molecular mass was fixed as 226 Da by pseudomolecular ions at m/z 244 [M + + NH 4 ] and 226 [M + + NH 4 -H 2 O] on CIMS. An APT spectrum showed that the compound contained two methyl, six methylene, three methine, and two quaternary carbons, according to a formula C 13 H 22 O 3 , in agreement with chemical shifts. The proton signals at δ 7.44 and 6.11 and a carbon signal at δ 173.2 indicated that the compound had an R, -unsaturated lactone, ester, or acid moiety. The molecular formula demands three double-bond equivalents. As two are accounted for by an ester or lactone carbonyl and a double bond, the molecule must be monocyclic. The H-H COSY spectrum showed couplings between the two olefinic protons and a multiplet at δ 5.01, indicating an oxygenated carbon next to the double bond. This methine showed further coupling to two methylene protons, which, in turn, were coupled to another methylene group. An HMQC spectrum correlated the proton signal at δ 5.01 to a methine signal at δ 83.4. This sequence resulted in fragment a.Additionally, the 1 H NMR spectrum showed a clear quartet and a triplet, indicating the presence of an isolated ethyl group in the molecule. A signal for an isolated me...

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Three new sesquiterpene quinols (1, 2, and 5) and two known ones (3 and 4) were isolated along with halistanol sulfate (6) from a marine sponge of the genus Aka collected from Yap Island, Federated States of Micronesia. Their structures were determined from spectral data, and the structure of siphonodictyal C (3) was revised. Sulfates 3 and 6 inhibit CDK4/cyclin D1 complexation, whereas 1 and 4 do not.