Ginseng fermented by mycotoxin non-producing Aspergillus niger: ginsenoside analysis and anti-proliferative effects

Korean ginseng was fermented using Aspergillus niger (A. niger) FMB S494 and mycotoxins such as ochratoxin and fumonisin were not detected in the fermented ginseng. Protopanaxadiol-type ginsenosides such as glycosylated forms of Rb1, Rb2, Rc, and Rd decreased to 0 while compound K (cK) increased from 0 to 9 × 10⁴ ppm in the extract of fermented ginseng. Protopanaxtriol-type ginsenosides such as Re and Rg1 decreased from 7.1 × 10⁴ to 3.0 × 10⁴ ppm and 6.8 × 10⁴ to 4.6 × 10⁴ ppm, respectively. Rg2 and Rh1 increased from 0 to 1.9 × 10⁴ ppm and 0 to 2.7 × 10⁴ ppm, respectively. We can demonstrate that A. niger was more inclined to transform protopanaxadiol-type ginsenosides. Moreover, fermented ginseng extract showed a dramatically enhanced anti-proliferative effect on human HT-29 cell line with a minimum effective concentration of about 1 µg/mL, which might be attributed to the high degree of biotransformation of ginsenosides, especially the high output of ginsenoside cK.