title: Fungal sensitivity to and enzymatic deglycosylation of ginsenosides.
abstract: A ginseng pathogen, Cylindrocarpon destructans, and five nonpathogens were tested for their sensitivity to a total ginsenoside fraction (T-GF), a protopanaxadiol-type ginsenoside fraction (PPD-GF) and a protopanaxatriol-type ginsenoside fraction (PPT-GF) from the roots of Panax ginseng C.A. Meyer. The results showed that T-GF inhibited growth of the five ginseng nonpathogens, while it promoted growth of the ginseng pathogen C. destructans. PPT-GF and PPD-GF both inhibited the growth of the five ginseng nonpathogens, although the activity of PPT-GF was higher than that of PPD-GF. PPT-GF and PPD-GF exhibited different activities on C. destructans: PPT-GF inhibited its growth, whereas PPD-GF significantly enhanced its growth. The subsequent analysis of enzymatic degradation of ginsenosides by the test fungi showed that C. destructans can consecutively hydrolyze the terminal monosaccharide units from the sugar chains attached at C3 and C20 in PPD-type ginsenosides by extracellular glycosidase activity to yield four major products, gypenoside XVII (G-XVII), compound O, compound Mb and the ginsenoside F(2). By contrast, the ginseng nonpathogens Aspergillus nidulans and Cladosporium fulvum have no extracellular glycosidase activity toward sugar chains attached to C3 in PPD-type ginsenosides. These results indicated that ginsenosides might act as host chemical defenses, while the ginseng root pathogenic fungi might counter their toxicity by converting PPD-type ginsenosides into growth or host recognition factors. The ability of ginseng root pathogens to deglycosylate PPD-type ginsenosides may be a pathogenicity factor.
authors.affiliation: School of Life Sciences, Northeast Normal University, Changchun 130024, PR China.
authors.forename: Xuesong
authors.initials: X
authors.lastname: Zhao
authors.forename: Juan
authors.initials: J
authors.lastname: Gao
authors.forename: Chengcheng
authors.initials: C
authors.lastname: Song
authors.forename: Qiang
authors.initials: Q
authors.lastname: Fang
authors.forename: Nan
authors.initials: N
authors.lastname: Wang
authors.forename: Tianjiao
authors.initials: T
authors.lastname: Zhao
authors.forename: Dongbo
authors.initials: D
authors.lastname: Liu
authors.forename: Yifa
authors.initials: Y
authors.lastname: Zhou
mesh_terms: D000935:Antifungal Agents / Q000032:analysis / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D036145:Ginsenosides / Q000032:analysis / Q000737:chemistry / Q000494:pharmacology*; D015394:Molecular Structure; D005894:Panax / Q000737:chemistry* / Q000382:microbiology; D018517:Plant Roots / Q000737:chemistry; D012502:Sapogenins / Q000737:chemistry
chemical_list: D000935:Antifungal Agents; D036145:Ginsenosides; D012502:Sapogenins; C081552:protopanaxatriol; C062916:protopanaxadiol