Innovative Approach to the Accumulation of Rubrosterone by Fermentation of Asparagus filicinus with Fusarium oxysporum.

Rubrosterone, possessing various remarkable bioactivities, is an insect-molting C19-steroid. However, only very small amounts are available for biological tests due to its limited content from plant sources. Fungi of genus Fusarium have been reported to have the ability to convert C27-steroids into C19-steroids. In this study, Asparagus filicinus, containing a high content of 20-hydroxyecdysone, was utilized to accumulate rubrosterone through solid fermentation by Fusarium oxysporum. The results showed that F. oxysporum had the ability to facilitate the complete biotransformation of 20-hydroxyecdysone to rubrosterone by solid-state fermentation. The present method could be an innovative and efficient approach to accumulate rubrosterone with an outstanding conversion ratio.