Biomedical subjects
Publications and source records attributed to D B Stierle.
Aspergillus parasiticus, a fungal isolate from a coast redwood tree (Sequoia sempervirens), has been shown to produce four new compounds, sequoiatones C-F (1-4). The structures of these compounds, all of which are cytotoxic to brine shrimp, were deduced by spectral analysis.
Botrytis sp., isolated from the inner bark of the Pacific yew, Taxus brevifolia, was shown to produce ramulosin (1), 6-hydroxyramulosin (2), and the new compound 8-dihydroramulosin (3). The structure of dihydroramulosin was deduced from the NMR spectra and confirmed by chemical conversion from ramulosin.
Investigation of the bioactive compounds from a Penicillium sp. isolated from the inner bark of the Pacific yew, Taxus brevifolia, led to the isolation of the known furanone 1, and a series of phomopsolides. The phomopsolide fractions contained phomopsolides A and B, which have previously been described, and three new phomopsolides. The structures of the new phomopsolides were deduced by comparison of their NMR spectra to those of the known compounds.
Two antimicrobial fractions were obtained from the sponge Calyx podatypa from the Bahamas. The less polar fraction contained the known compounds xestamines A [1] and B [2] and three new metabolites called xestamines D [3], E [4], and F [5]. The more polar fraction consisted of a mixture of xestamines G [6] and H [7].