Study on the preparation of rare ginsenoside F1 by enzymatic biotransformation of ginsenoside Rg1

Rare ginsenoside F1, a bioactive component of ginseng, possesses notable anti-tumour, anti-aging, and antioxidant properties; however, its low natural abundance and the difficulty of large-scale preparation limit its practical application. In this study, ginsenoside Rg1 was converted into rare ginsenoside F1 using a recombinant β-glucosidase (BgpA), BaBgl1A, and the products were analysed by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). The results demonstrated that BaBgl1A selectively hydrolysed the glucose moiety at the C-6 position of Rg1. The biotransformation conditions were optimised to pH 5.0, 45 °C, a substrate concentration of 2 mg/mL, and an enzyme loading of 2.0 U/mg. Under these conditions, the biotransformation was completed within 12 h with a biotransformation conversion of 98%, and the product structure was confirmed by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS). Molecular docking analysis revealed that hydrogen bonding was the dominant interaction between Rg1 and BaBgl1A, with an optimal binding energy of −7.9 kcal/mol. Rg1 bound to the active site of BaBgl1A through three key amino acid residues (ALA-178, SER-43, and SER-354), which facilitated the hydrolysis of the outer Glc residue at the C-6 position. These findings provide a novel strategy for the efficient large-scale preparation of rare ginsenoside F1.