New Triterpenoid from Novel Triterpenoid 15-

Area of Science:

• Microbiology
• Biochemistry
• Natural Products Chemistry

Background:

• Triterpenoids, such as Ganoderic acid A (GAA) from Ganoderma lucidum, possess medicinal properties but require biotransformation for enhanced bioavailability.
• The diverse microflora in animal intestines represents a potential source of microorganisms capable of biotransforming complex natural products.

Purpose of the Study:

• To investigate the microbial biotransformation of Ganoderic acid A (GAA) using bacteria isolated from zebrafish intestines.
• To identify novel biotransformation pathways and compounds derived from GAA.

Main Methods:

• Isolation and screening of intestinal bacteria from zebrafish excreta for their ability to biotransform GAA.
• Identification of a positive bacterial strain (GA A07) using 16S rRNA gene sequencing (Bacillus sp.).
• Purification and structural elucidation of the biotransformed metabolite using preparative HPLC, mass spectrometry, and NMR spectroscopy.

Main Results:

• A Bacillus sp. strain (GA A07) was identified as capable of biotransforming GAA.
• The major biotransformed metabolite was purified and identified as GAA-15-O-β-glucoside.
• This study reports the first instance of Ganoderma triterpenoid glycosylation and a novel 15-O-glycosylation microbial biotransformation pathway.

Conclusions:

• Gut microflora harbors bacteria with the potential to biotransform fungal triterpenoids.
• The discovery of GAA-15-O-β-glucoside represents a new compound and a novel microbial biotransformation pathway (15-O-glycosylation) for triterpenoids.
• This finding opens avenues for exploring microbial glycosylation in natural product modification.