Microbial conversion of major ginsenoside Rb1 to minor ginsenoside Rd by Indian fermented food bacteria

Abstract

Ginsenoside Rb1 is the predominant secondary metabolite (saponin) in Panax ginseng. Hydrolysis of the sugar residues in Rb1 yields more pharmaceutically active ginsenosides like Rd, Rg3, F2, Rh2 and
C-K. Among them, the minor ginsenoside Rd enhances the differentiation of neural stem cells, protects neurons from neurotoxic chemicals, decreases urea nitrogen and creatinine in kidney. It also protects the kidney from apoptosis and DNA fragmentation caused by cancer and chemical drugs and is more useful therapeutically than the major ginsenoside Rb1. Bacteria showing b-glucosidase activity were isolated from fermented Indian food using esculin-MRS agar. Bacteria from Amla in sugar syrup and Boiled Amla in jaggery syrup converted ginsenoside Rb1 to minor ginsenoside Rd. TLC and HPLC analysis showed that with increase in incubation time the conversion of Rb1 to Rd also increased. The 16s rDNA sequence was determined and the bacteria showed 93% sequence similarity to Brumimicrobium mesophilum.