BIOTRANSFORMATION OF GINSENOSIDE Rb_1 INTO F-2 AND COMPOUND K BY BACTERIUM Sphingomonas sp. BG 25

摘要

Triterpenoid saponins and ginsenosides, the majority of which contain protopanaxadiol or protopanaxatriol as the aglycon, are important biologically active compounds of Panax ginseng C. A. Meyer. One of the principal ginsenosides, Rb_1 (1), has β-sophorose and β-gentiobiose residues in the C-3 and C-20 positions, respectively, of 20(S)-protopanaxadiol. The minor ginsenoside F-2 (2) with glucose residues on C-3 and C-20 and compound K (3) with only one glucose on C-20 have structures close to that of Rb_1 and are practically absent in ginseng roots [1]. Saponins 2 and 3 have broader spectra of biological activity than Rb_1. For example, compound K inhibits growth of cultivated melanoma B16-B6, hepatocellular carcinoma Hep-G2, and lung carcinoma 95-D cells whereas F-2 induces apoptosis of breast cancer stem cells [1, 2].