@article {Chang234, author = {Thomas K. H. Chang and Jie Chen and Xiao Wei Teng}, title = {DISTINCT ROLE OF BILOBALIDE AND GINKGOLIDE A IN THE MODULATION OF RAT CYP2B1 AND CYP3A23 GENE EXPRESSION BY GINKGO BILOBA EXTRACT IN CULTURED HEPATOCYTES}, volume = {34}, number = {2}, pages = {234--242}, year = {2006}, doi = {10.1124/dmd.105.005751}, publisher = {American Society for Pharmacology and Experimental Therapeutics}, abstract = {In the present study, primary cultures of rat hepatocytes were treated for 48 h with one of several extracts of Ginkgo biloba (10, 100, or 1000 μg/ml). Maximal increase in CYP2B1 and CYP3A23 mRNA levels was obtained at 100 μg/ml. This concentration of G. biloba extract also increased CYP3A2 and CYP3A18 mRNA expression in addition to CYP2B-mediated 7-benzyloxyresorufin O-dealkylation (BROD) and CYP3A-mediated testosterone 6β-hydroxylation. In other experiments, cultured hepatocytes were treated for 48 h with bilobalide, ginkgolide A, ginkgolide B, ginkgolide C, ginkgolide J, kaempferol, quercetin, isorhamnetin, or a flavonol diglycoside at a concentration that represented the level present in a 100 μg/ml concentration of an extract. Only bilobalide (2.8 μg/ml) increased CYP2B1 mRNA expression, and the -fold increase (7.9 {\textpm} 0.5; mean {\textpm} S.E.M.) was similar to that (8.3 {\textpm} 1.7) by the extract. By comparison, only ginkgolide A (1.1 μg/ml) increased CYP3A23 mRNA expression, but the extent (2.6 {\textpm} 0.5-fold) was less than the 5.3 {\textpm} 1.7-fold increase by the extract. A greater concentration (5 μg/ml) of ginkgolide A was required to elevate CYP3A2 and CYP3A18 mRNA expression. Over the range of 1 to 5 μg/ml, bilobalide increased CYP2B1 mRNA and BROD, but not CYP3A23 mRNA or testosterone 6β-hydroxylation, whereas ginkgolide A increased CYP3A23 mRNA and testosterone 6β-hydroxylation, but not CYP2B1 mRNA or BROD. Overall, our novel results indicate a distinct role of bilobalide and ginkgolide A in the modulation of CYP2B1 and CYP3A23 gene expression and enzyme activities by G. biloba extract in primary cultures of rat hepatocytes. The American Society for Pharmacology and Experimental Therapeutics}, issn = {0090-9556}, URL = {https://dmd.aspetjournals.org/content/34/2/234}, eprint = {https://dmd.aspetjournals.org/content/34/2/234.full.pdf}, journal = {Drug Metabolism and Disposition} }