Assessment of a pharmacokinetic and pharmacodynamic interaction between simvastatin and Ginkgo biloba extracts in healthy subjects.

1. Ginkgo biloba extract (GBE) is one of the most commonly used herbal remedies worldwide. It is usually concomitantly administrated with statins to treat diseases in geriatric patients. We aim to determine the influence of GBE on the pharmacokinetics (PK) and pharmacodynamics of simvastatin, which is currently unknown. 2. An open-label, randomized, two-period, two-treatment, balanced, crossover study was performed in 14 healthy volunteers. Subjects received simvastatin 40 mg once daily, co-treated with placebo or GBE 120 mg twice daily. Each treatment was administered for 14 d, separated by a wash-out period of 1 month. Simvastatin, simvastatin acid and lipoprotein concentrations were assessed. 3. GBE administration reduced mean simvastatin area under the curve (AUC)0-24, AUC0-∞ and Cmax by 39% (p = 0.000), 36%(p = 0.001) and 32% (p = 0.002), respectively, but did not cause significant differences in simvastatin acid PK or its cholesterol-lowering efficacy. 4. GBE consumption decreased simvastatin system exposure, but did not affect simvastatin acid PK. However, we cannot rule out the possibility for a pharmacodynamic interaction between GBE and simvastatin in vivo.

Effects of Ginkgo biloba extracts on pharmacokinetics and efficacy of atorvastatin based on plasma indices.

Ginkgo biloba extract (GBE) is one of the most widely used herbal medicines in the world. It is often administered in combination with statins to treat diseases, especially some nervous system disorders. We aimed to investigate the influences of GBE on pharmacokinetics and efficacy of atorvastatin, which are currently unclear. Sixteen volunteers received a single oral dose of 40 mg atorvastatin, followed by a wash-out period of at least 5 days. Then the volunteers took 360 mg GBE daily for 14 days, followed by a single dose of 40 mg atorvastatin. Serial blood samples obtained over a period of 48 h after atorvastatin ingestion were subjected to determination of atorvastatin plasma concentrations and markers of cholesterol synthesis (lathosterol) and cholesterol absorption (sitosterol). With GBE administration, AUC0₋48, AUC(0-∞) and C(max) of atorvastatin were reduced by 14.27% (p = 0.005), 10.00% (p = 0.03) and 28.93% (p = 0.002), respectively; Vd/F and CL/F of atorvastatin were increased by 31.95% (p = 0.017) and 6.48% (p = 0.044). After 14 days of treatment, GBE has no significant effects on cholesterol-lowering efficacy of atorvastatin. This study suggests that GBE slightly decreases the plasma atorvastatin concentrations, but has no meaningful effect on the cholesterol-lowering efficacy of atorvastatin.

Antiproliferative activity of the total saponin of Solanum lyratum Thunb in Hela cells by inducing apoptosis.

Total saponin of Solanum lyratum Thunb (TSSLT), a species of natural biologically active substances isolated from Solanum lyratum Thunb, possesses various bioactivities. It has been proposed that the induction of apoptosis may be the basis of its antitumor activity. However, the molecular mechanism underlying the total saponin-induced apoptotic process remains unknown. In the present study, we describe the anti-proliferative effect of TSSLT on human cervical cancer cells (Hela). The TSSLT induced apoptosis of Hela in a time-dependent manner with an IC50 for cell viability of 6 microg/ml. The TSSLT-induced cell death was characterized by changes in cell morphology, DNA fragmentation, activation of caspase-like activities, poly (ADP-ribose) polymerase (PARP) cleavage and release of cytochrome c (cyt c) into cytosol. TSSLT activated various caspases such as caspase-3, -8, and -9 (like) activities but not caspase-1 like activity. The cell death was completely prevented by the pan caspase inhibitor benzyloxy carbonyl-Val-Ala-Asp- fluoromethyl-ketone (Z-VAD-FMK). More than 80% cell survival was observed in the presence of a caspase-3 inhibitor. In addition, treatment with TSSLT induced the increase of Bax:Bcl-2 ratio in Hela cells. These results suggest that the induction of apoptosis by TSSLT involves multiple pathways antigen including death receptor and mitochondrial pathway and strongly suggest that the mitochondrial pathway was mediated by low expression of Bcl-2 and upregulation of Bax, release of cyt c and subsequent activation of caspase-3 followed by down stream events leading to apoptotic cell death.