Cyclosporin A affects the bioavailability of ginkgolic acids via inhibition of P-gp and BCRP

•GA (C15:1) and GA (C17:1) are substrates of P-gp and BCRP.•The bioavailability of GAs effluxed by both P-gp and BCRP is limited.•CsA increases bioavailability and brain concentration of GAs in vivo via inhibiting P-gp and BCRP.

Ginkgolic acids (GAs) in natural product Ginkgobiloba L. are the pharmacological active but also toxic components. Two compounds, GA (C15:1) and GA (C17:1) are the most abundant GAs. In this study, several in vitro and in vivo models were applied to investigate transport mechanism of GAs. A rapid and sensitive LC–MS/MS method for the simultaneous determination of GA (C15:1) and GA (C17:1) was applied to analyze the biological specimens. The Papp(AP→BL) values of GA (C15:1) and GA (C17:1) were 1.66–2.13 × 10−6 cm/s and 1.34–1.85 × 10−6 cm/s determined using MDCK and MDCK-MDR1 cell monolayers, respectively. The Papp(BL→AP) were remarkably greater in the MDCK-MDR1 cell line, which were 6.77–11.2 × 10−6 cm/s for GA (C15:1) and 4.73–5.15 × 10−6 cm/s for GA (C17:1). Similar results were obtained in LLC-PK1 and LLC-PK1-BCRP cell monolayers. The net efflux ratio of GA (C15:1) and GA (C17:1) in both cell models was greater than 2 and markedly reduced by the presence of Cyclosporin A (CsA) or GF120918, inhibitors of P-gp and BCRP, suggesting that GAs are P-gp and BCRP substrates. The results from a rat bioavailability study also showed that co-administrating CsA intravenously (20 mg/kg) could significantly increase GA (C15:1) and GA (C17:1) AUC0−t by 1.46-fold and 1.53-fold and brain concentration levels of 1.43-fold and 1.51-fold, respectively, due to the inhibition of P-gp and BCRP efflux transporters by CsA.

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