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Induction of glutathione synthesis in human keratinocytes by Ginkgo biloba extract (EGb761)
Author(s) -
Rimbach Gerald,
Gohil Kishorchandra,
Matsugo Seiichi,
Moini Hadi,
Virgili Claude Saliou, Fabio,
Weber Packer Stefan U. , Lester
Publication year - 2001
Publication title -
biofactors
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.204
H-Index - 94
eISSN - 1872-8081
pISSN - 0951-6433
DOI - 10.1002/biof.5520150104
Subject(s) - ginkgo biloba , glutathione , biochemistry , western blot , flavonoid , kaempferol , cell culture , chemistry , quercetin , microbiology and biotechnology , biology , enzyme , pharmacology , antioxidant , genetics , gene
Abstract The objective of the present study was to characterize the action of Ginkgo biloba extract (EGb761) and its sub‐fractions on glutathione homeostasis in a human keratinocyte cell culture model. Cells were incubated with EGb761, its purified flavonoid (quercetin, kaempferol, rutin) or terpenoids (gingkolides A, B, C, J, bilobalide) constituents or the vehicle for up to 72 hours. Incubation of keratinocytes with the purified flavonoids or terpenoids did not affect cellular GSH levels. However, EGb761 treatment (up to 200 μg/ml) resulted in a dose‐dependent increase of cellular GSH. Western blot analysis of extracts from cells treated with EGb761 revealed increased levels of the catalytic subunit of γ glutamylcysteinyl synthetase ( γ GCS), the rate‐limiting enzyme in GSH synthesis. The abundance of mRNA for the catalytic subunit (assayed by RT‐PCR) was also increased by the treatment with EGb761. Increased levels of cellular GSH by EGb761 were also observed in other cell lines including those from human bladder and liver as well as in murine macrophages indicating that the induction of γ GCS mRNA, protein and GSH may be an ubiquitous effect of EGb761 in mammalian cells.