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Three novel cytotoxic linear peptides obtained from the Didemnid ascidian Diplosoma virens, which incorporate thiazole moieties, are structurally characterized by one and two dimensional nuclear magnetic spectroscopy. The structures are then verified through high performance liquid chromatography following acid hydrolysis and derivatization using 1-fluoro-2,4-dinitrophen-5-yl-L-alanine under Marfey's conditions. Virenamides A-C have molecular formulas of C31H46N4O2S, C30H38N4O2S and C34H38N4O2S, respectively.

Research has been conducted on cyclodepsipeptides isolated from New Zealand Cladobotryum sp. The structures of these cyclodepsipeptides have been elucidated from NMR and HRESIMS experiments, and their stereochemistry has been analyxed vir the use of X-ray crystallography and chemical degradation.

Parkinson's disease (PD) is an incurable neurodegenerative disorder with a high prevalence rate worldwide. The fact that there are currently no proven disease-modifying treatments for PD underscores the urgency for a more comprehensive understanding of the underlying disease mechanism. Chemical probes have been proven to be powerful tools for studying biological processes. Traditional Chinese medicine (TCM) contains a huge reservoir of bioactive small molecules as potential chemical probes that may hold the key to unlocking the mystery of PD biology. The TCM-sourced chemical approach to PD biology can be advanced through the use of an emerging cytological profiling (CP) technique that allows unbiased characterization of small molecules and their cellular responses. This comprehensive technique, applied to chemical probe identification from TCM and used for studying the molecular mechanisms underlying PD, may inform future therapeutic target selection and provide a new perspective to PD drug discovery.

Bioassay-guided fractionation of a CH2Cl2/MeOH extract of the sponge Suberea clavata using the serine protease factor XIa to detect antithrombotic activity led to the isolation of the new marine natural products, clavatadines A and B. Clavatadines A and B inhibited factor XIa with IC50's of 1.3 and 27 microM, respectively. A crystal structure of protein-inhibitor (clavatadine A) complex was obtained and revealed interesting selective binding and irreversible inhibition of factor XIa. The cocrystal structure provides guidance for the design and synthesis of future factor XIa inhibitors as antithrombotic agents.

[reaction: see text] HA 23, a novel cyclodepsipeptide (1) of mixed peptide-polyketide origins, was isolated from a fungal isolate of a Fusarium sp. The structure was determined from 1D and 2D NMR and mass spectral data.

Three new linear cytotoxic tripeptides, virenamides A-C have been isolated from extracts of the Didemnid ascidian Diplosoma virens collected on the Great Barrier Reef, Australia. Their structures were deduced from 1D and 2D NMR spectral data and confirmed by HPLC analysis of the constituent amino acids after hydrolysis of the peptides and derivatization with 1-fluoro-2,4-dinitrophen-5-yl-L-alanine amide using Marfey's procedure.