Bioconversion of steroid compounds due to interaction of the bark extract of <i>Michelia champaca</i> with fungi <i>Curvularia verruculosa</i>

Functional groups bioconversion of steroid compounds was observed in the interaction of secondary metabolites of Michelia champaca with Curvularia verruculosa fungal. In an inhibited mechanism, this extract can lyse the cell walls of the fungus. This research aims to determine changes in secondary metabolite compounds involved in the inhibition process of M. champaca bark extract on the growth of the fungus C. verruculosa.The interaction of secondary metabolites of M. champaca with C. verruculosa fungi was observed by biomass test method and bioconversion analysis of steroid compounds was observed by gas chromatography-mass spectroscopy (GC-MS). Based on the biomass test of M. champaca bark extract with 1% concentration can inhibit the biomass formation of C. verruculosa fungal with inhibiting power is 74.73% and at 2% concentration has been able to inhibit completely the biomass formation of C. verruculosa fungal (100%) for a-8 days period of incubation. The bioconversion of the functional groups in steroid compounds was observed by changing allopregnane-7α, 11α-diol-3,20-dione compounds to pregnane-3,20-dione; pregnane-3,11-diol-20-one; and pregnenolone, as well as the bioconversion of β-sitosterol compounds to pseudosarsapogenin-5,20-dien; (3β, 24S)-stigmastane-5-en-3-ol; and (3β, 22E)-stigmastane-5,22-dien- 3-ol.