Fermentation-induced changes in Bupleurum: A study on flavonoids, polyphenols, antioxidant capacity, and metabolomic...

Previous studies have indicated that the process of herbal fermentation can enhance the bioactive components of the plant. Bupleurum, a traditional Chinese herb, is used to treat conditions such as colds and inflammation. This study used Bacillus velezensis PV810342 (with strong enzyme production) to ferment Bupleurum aqueous decoction for 48 h at 0%, 2%, 4%, 6%, 8%, and 10% inoculation rates. A comparative analysis of the Bupleurum aqueous decoction before and after fermentation revealed that the optimal levels of flavonoids (an increase of 62.7%) and polyphenols (an increase of 21.5%) were achieved with a 4% inoculation rate. There was also a 26.6% improvement in hydroxyl radical scavenging capacity and a 42.07% improvement in ferric reducing antioxidant power. However, there was a significant decrease in DPPH radical scavenging capacity. Metabolomic analysis revealed that B. velezensis PV810342 has been observed to modulate glyoxylate and dicarboxylate metabolism, phenylalanine metabolism, and tyrosine metabolism through co-metabolism, thereby influencing the contents of flavonoids, polyphenols, saponins, fatty acids, terpenoids, and alkaloids. Collectively, these findings suggest that Bacillus velezensis-fermented Bupleurum possesses elevated active components and antioxidant activity, suggesting its potential for further development in managing oxidative stress-related conditions.