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An endophytic Streptomyces sp. (AC-2) was isolated from the root of Cistanches deserticola Y.C.Ma.. Chemical investigations of the culture broth of AC-2 afforded fifteen compounds including K1115 A (1), tyrosol (2), phenylethylamine derivatives (3, 4), cyclic dipeptides (5-8), nucleosides and their aglycones (9-13), N-acetyltryptamine (14), and pyrrole-2-carboxylic acid (15). Only tyrosol can promote an increase of intracellular cAMP special on GPR12 transfected cells, such as CHO and HEK293, which means it may be a possible ligand for GPR12.

Two new compounds, 2, 3, 5-trimethyl-6-(3-oxobutan-2-yl)-4H-pyran-4-one (1) and (2R)-2, 3- dihydro-7-hydroxy-6, 8-dimethyl-2-[(E)-prop-1-enyl] chromen-4-one (2), together with six known compounds (3-8), were isolated from a deep-sea fungus, identified as Aspergillus sydowi, by a bioassay-guided method. Their structures were elucidated by spectroscopic methods and the cytotoxicities were evaluated by SRB method.

Two isocoumarin derivatives, stoloniferol A (1) and B (2), a known 5alpha, 8alpha-epidioxy-23-methyl-(22E, 24R)-ergosta-6, 22-dien-3beta-ol (3), and a known dihydrocitrinone (4) were isolated from the ethyl acetate extract of the sea squirt-derived fungus, Penicillium stoloniferum QY2-10, and a halophilic fungus, Penicillium notatum B-52, respectively. Their structures were elucidated by spectroscopic methods and optical rotation. The stereochemistry of 2 was determined on the basis of different NOE experiments and chemical transformation. Compound 3 showed cytotoxicity against P388 cells, with an IC50 value of 4.07 microM.

Four known butenolides were isolated from the ethyl acetate extracts of the culture broth of the marine-derived bacterium, Streptoverticillium luteoverticillatum, by bioassay-guided fractionation. The structures were identified on the basis of spectral data. The absolute configuration of compound (1) was determined by CD spectrum for the first time. Compounds 1-4 showed in vitro cytotoxicity against the murine lymphoma P388 and human leukemia K562 cell lines. This is the first report on the isolation of butenolides from the marine bacterium, Streptoverticillium luteoverticillatum, and their cytotoxic activities.