An approach to speed up the isolation of hydrophilic metabolites from natural sources at semipreparative level by using a hydrophilic-lipophilic balance/mixed-mode strong cation exchange-high-performance liquid chromatography/mass spectrometry system.

An approach to speed up the isolation of hydrophilic metabolites in complex natural matrixes by using a HLB/MCX-HPLC/MS system based on the retention properties of hydrophilic-lipophilic and cation exchange polymeric cartridges was developed. This methodology was successfully applied to the re-isolation of small water soluble compounds with completely different structures from two different natural extracts such as a dipeptide (vanchrobactin) from a bacterium culture broth and a pyrrolidine bearing a carboxylic acid moiety (clionapyrrolidine A) from a sponge. This method improved not only the efficiency of the isolation methodology but also the isolation time in relation to the existing methods.

Optimization strategies for the analysis and purification of drug discovery compounds by reversed-phase high-performance liquid chromatography with high-pH mobile phases.

Careful selection of both high-pH mobile phase as well as organic modifier, was performed in order to develop and optimize HPLC conditions for the separation of drug discovery compounds. High-pH mobile phases provide excellent chromatographic resolution and increased mass loading of basic compounds. The analytical methods so defined have been successfully transferred to preparative automated UV-directed purification, an important fact due to the increasing number of samples requiring purification. It should be noted that, the single prerequisite for this approach is an analytical LC-UV-MS run, therefore the system has the ability to collect only fractions likely to contain the target product. A cost-effective strategy for maximizing the purification of drug discovery compounds is proposed.

A new secosterol from the Indonesian octocoral Pachyclavularia violacea.

A new secosterol (1), along with pachyclavulariaenone B (3), was isolated from Pachyclavularia violacea. The structures of these compounds were established on the basis of the NMR and MS experiments.

New Xenia diterpenoids from the Indonesian soft coral Xenia sp.

Two new xeniolides, xeniolide-F (1) and 9-hydroxyxeniolide-F (2), along with isoxeniolide-A (3) and 7,8-oxido-isoxeniolide-A (4), have been isolated from Xenia sp. and their structures established on the basis of extensive NMR and MS studies.