DISTINCT ROLE OF BILOBALIDE AND GINKGOLIDE A IN THE MODULATION OF RAT CYP2B1 AND CYP3A23 GENE EXPRESSION BY GINKGO BILOBA EXTRACT IN CULTURED HEPATOCYTES

2005 ◽  
Vol 34 (2) ◽  
pp. 234-242 ◽  
Author(s):  
Thomas K. H. Chang ◽  
Jie Chen ◽  
Xiao Wei Teng
Keyword(s):  
Gene Expression ◽  
Ginkgo Biloba ◽  
Ginkgo Biloba Extract ◽  
Cultured Hepatocytes ◽  
Ginkgolide A ◽  
Distinct Role

Quantitative GC-FID and UHPLC-DAD Evaluation of Bioactive Compounds Extracted from Ginkgo biloba

2020 ◽  
Vol 16 (7) ◽  
pp. 893-904
Author(s):  
Alessandra von Ahn ◽  
João Henrique Z. dos Santos
Keyword(s):  
Ginkgo Biloba ◽  
Extraction Efficiency ◽  
Extraction Methods ◽  
Ginkgo Biloba Extract ◽  
Previous Method ◽  
Array Detector ◽  
Ginkgolide B ◽  
Detection Techniques ◽  
Ginkgolide A ◽  
Terpene Trilactones

Background: The official compendium of the quantification of ginkgo flavonoids from Ginkgo biloba extract has been proposed using HPLC. The drawbacks of this technique appear to be due to the restricted efficiency in terms of the recovery results and suitability of the system for the quantification of these compounds. This study investigated the potential advantages and limitations of the development of efficient extraction methods for the recovery of flavonol glycosides (quercetin, kaempferol and isorhamnetin) and terpene trilactones (bilobalide, ginkgolide A, ginkgolide B and ginkgolide C) using extraction, quantification and detection techniques, namely, GC-FID and UHPLC-DAD, which are alternatives to those techniques available in the literature. Methods: Two different extraction methodologies have been developed for the determination of flavonoids (quercetin, kaempferol and isorhamnetin) and terpene trilactones (bilobalide, ginkgolide A, ginkgolide B and ginkgolide C) using ultra-high-pressure liquid chromatography coupled to a diode array detector and gas chromatography coupled to a flame ionization detector. Results: In this study, the Ginkgo biloba extract mass, hydrolysis preparation method (with or without reflux), and volume of the extraction solution seemed to affect the ginkgo flavonoid recovery. The UHPLC-based method exhibited higher extraction efficiency for ginkgo flavonoid quantification compared to the pharmacopoeial method. The developed method exhibited higher extraction efficiency for terpene quantification compared to the previous method that used extractive solution without pH adjustment, with less time of extraction and less amount of the sample and organic solvent aliquots. Conclusion: The UHPLC and GC analysis methods established in this study are both effective and efficient. These methods may improve the quality control procedures for ginkgo extract and commercial products available in today´s natural health product market. The results indicate that redeveloped extraction methods can be a viable alternative to traditional extraction methods.

Effect of Ginkgo biloba extract on rat hepatic microsomal CYP1A activity: role of ginkgolides, bilobalide, and flavonols

2004 ◽  
Vol 82 (1) ◽  
pp. 57-64 ◽  
Author(s):  
I fan Kuo ◽  
Jie Chen ◽  
Thomas K.H Chang
Keyword(s):  
Ginkgo Biloba ◽  
Ginkgo Biloba Extract ◽  
Inhibitory Potency ◽  
Hepatic Microsomes ◽  
Cyp1a Activity ◽  
Ginkgo Biloba Extracts ◽  
The Individual ◽  
Vitro Effect

The present study investigated the in vitro effect of Ginkgo biloba extracts and some of the individual constituents (ginkgolides, bilobalide, and flavonols such as kaempferol, quercetin, isorhamnetin, and their glycosides) on CYP1A-mediated 7-ethoxyresorufin O-dealkylation in hepatic microsomes isolated from rats induced with β-naphthoflavone. G. biloba extract competitively inhibited CYP1A activity, with an apparent Ki value of 1.6 ± 0.4 µg/mL (mean ± SE). At the concentrations present in the G. biloba extracts, ginkgolides A, B, C, and J and bilobalide did not affect CYP1A activity, whereas kaempferol (IC50 = 0.006 ± 0.001 µg/mL, mean ± SE), isorhamnetin (0.007 ± 0.001 µg/mL), and quercetin (0.050 ± 0.003 µg/mL) decreased this activity. The monoglycosides (1 and 10 µg/mL) and diglycosides (10 µg/mL) of kaempferol and quercetin but not those of isorhamnetin also inhibited CYP1A activity. The order of inhibitory potency was kaempferol ~ isorhamnetin > quercetin, and for each of these flavonols the order of potency was aglycone >> monoglycoside > diglycoside. In summary, G. biloba extract competitively inhibited rat hepatic microsomal CYP1A activity, but the effect was not due to ginkgolides A, B, C, or J, bilobalide, kaempferol, quercetin, isorhamnetin, or the respective flavonol monoglycosides or diglycosides.Key words: bilobalide, CYP1A, cytochrome P450, Ginkgo biloba, ginkgolide, flavonol.

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