Optimal bioconversion for compound K production from red ginseng root (C.A. Mayer) by sequential enzymatic hydrolysis and its characteristics

Compound K (CK; 20-O-β-(d-glucopyranosyl)-20(S)-protopanaxadiol) is one of the metabolites of ginsenosides contained in red ginseng (RG) and is known to have high bioavailability. This study aimed to establish the optimal conditions for enzyme treatment to convert ginsenosides from RG extract to CK, and to prove the characteristics of bioconverted red ginseng (BRG) extract. CK was not detected in unenzyme-treated RG extract, and in the single-step enzyme treatment, it was produced at less than 4.58 mg/g only in treatment group with Pyr-flo or Sumizyme AC (at 50 °C for 48 h). The highest yield of CK (14.32 mg/g) was obtained by Ultimase MFC treatment at 50 °C for 48 h after treatment with a mixture of Pyr-flo and Rapidase at 50 °C for 24 h. Total polyphenol, 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)) (ABTS) radical scavenging activity were higher in BRG than in RG (p < 0.5). High-fat diet (HD) rat fed 1% BRG had significantly lower body weight, heart weight, fat pads (periosteal fat, epididymal fat), serum glucose levels, and hepatic triglyceride levels than those HD rat fed 1% RG (p < 0.05). In conclusion, the sequential enzymatic bioconversion was produces higher CK in RG root extract than single-step enzyme treatment.