The taccalonolides are microtubule stabilizers isolated from plants of the genus Tacca that show potent in vivo antitumor activity and the ability to overcome multiple mechanisms of drug resistance. The most potent taccalonolide identified to date, AJ, is a semisynthetic product generated from the major plant metabolite, taccalonolide A, in a two-step reaction. The first step involves hydrolysis of taccalonolide A to generate taccalonolide B and then this product is oxidized to generate an epoxide group at C22-23. To generate sufficient taccalonolide AJ for in vivo antitumor efficacy studies, the hydrolysis conditions for the conversion of taccalonolide A to B were optimized. During purification of the hydrolysis products, we identified the new taccalonolide, AO (1) along with taccalonolide I. When the same hydrolysis reaction was performed on a taccalonolide E-enriched fraction four new taccalonolides, assigned to AK, AL, AM, and AN (2–5), were obtained in addition to the expected product taccalonolide N. Biological assays were performed on each of the purified taccalonolides which allowed for increased refinement of the structure-activity relationship of this class of compounds.

Fusarium proliferatum was isolated as a major pathogen causing the Fusarium disease in harvested banana fruit. One of its major compounds, fusaric acid, was identified by high-performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS). Because the light intensity of the luminescent bacterium Vibrio qinghaiensis sp. Nov. Q67 can be inhibited by fusaric acid, the fusaric acid content of F. proliferatum was assessed and compared by both the HPLC and luminescent bacterium methods. Although both methods afforded almost similar values of fusaric acid, the latter indicated slightly lower content than the former. Czapek medium was more suitable for the growth of F. proliferatum and fusaric acid production than modified Richard medium, with an optimum pH of approximately 7.0. However, no significant (P < 0.05) correlation was obtained between the fusaric acid production and growth of mycelia of F. proliferatum. The study suggests that the bioevaluation by use of the luminescent bacterium was effective in monitoring fusaric acid production by F. proliferatum without expensive equipment.

No abstract

No abstract