Bioconversion of Ginsenoside Rf into Its Hydrated Derivative with Elevated Anti-inflammatory Effect by a Highly...

The presence of 25-OH moiety has been proved to enhance the bioactivity of dammarane saponins in many cases. However, such modification by previous strategies had compromised yield and purity of target products. Herein ginsenoside Rf was specifically transformed into 25-OH-(20S)-Rf with a conversion rate of 88.03 % by a Cordyceps Sinensis-mediated biocatalytic system. The formulation of 25-OH-(20S)-Rf was calculated by HRMS, whilst its structure was validated by ¹ H-NMR, ¹³ C-NMR, HSQC, and HMBC analysis. Time-course experiments unveiled straightforward hydration of the double bond on Rf with undetectable side reactions and maximum production of 25-OH-(20S)-Rf on the 6^th day, which collectively suggested the suitable timing of harvesting this target compound. In vitro bioassay of (20S)-Rf and 25-OH-(20S)-Rf against lipopolysaccharide-induced macrophages indicated a significant boost of anti-inflammatory effects after the C24-C25 double bond was hydrated. Therefore, the biocatalytic system in this article could be leveraged to deal with macrophage-mediated inflammation under defined circumstances.