The effect of Ginkgo biloba extract (EGb 761) on hepatic sinusoidal endothelial cells and hepatic microcirculation in CCl4 rats

Evaluation of whey protein sources on performance, liver antioxidants and immune responses of broiler chickens challenged with ethanol

To evaluate the effects of whey protein (WP) sources on performance, liver antioxidants and immune responses of broiler chickens, 300 one-d-old male Ross 308 chickens were randomly allocated into six treatments with five replications of 10 birds each. This study was conducted on the basis of a completely randomized design in a 3 × 2 factorial arrangement with dietary supplemental WP sources (no WP; 2% WP and 2% whey protein concentrate (WPC)) and ethanol (zero and 6%) into drinking water. Birds were challenged with ethanol 6% from 10 to 24 days of age. Growth performance, immune responses, intestinal morphology and antioxidant enzymes were assessed in both challenged and non-challenged groups. There was a significant interaction between ethanol and WP sources for growth performance, so that weight gain (WG), feed intake (FI) and feed conversion ratio (FCR) were significantly improved in broiler chickens challenged with ethanol and fed with WP (p < .05). Intestinal morphology, humoral responses and heterophil to lymphocyte ratio (H/L) were not affected by WP sources. Cellular immunity responses were significantly lower in control group and challenged birds fed with WP compared with other groups after 48 hr of phytohemagglutinin-P (PHA-P) injection. Ethanol challenge decreased liver antioxidant enzyme activities and increased levels of malondialdehyde (MDA) and alanine aminotransferase (ALT) activities. Dietary inclusion of WP and WPC increased levels of liver antioxidant enzymes and decreased MDA and ALT activities. It can be recommended to use WP for improving the growth performance and liver antioxidant enzymes in broiler chickens challenged with ethanol.

Pediatric cone beam CT on Varian Halcyon and TrueBeam radiotherapy systems: radiation dose and positioning accuracy evaluations

Medical exposure to ionizing irradiation has become a recognised carcinogenic risk. Balancing the concomitant imaging dose and positioning accuracy is critical in image-guided-radiotherapy (IGRT) especially for children, whose higher biological susceptibility and longer expected life make them more vulnerable to develop secondary cancer. This work aims to evaluate and benchmark the imaging dose and positioning accuracy of a new MV cone-beam-CT (CBCT)-guided IGRT system, Varian Halcyon, against conventional kV CBCT. Weighted-CT-dose-index (CTDI_w) were measured for Varian TrueBeam kV CBCT, and computed for Halcyon MV CBCT using Eclipse system as validated before. Simulating the IGRT workflow, the positioning accuracy of correcting a known shift was tested on various regions of 1-year, 5-year and adult anthropomorphic phantoms, respectively. Inter-scanner and inter-protocol comparisons of dose and accuracy were performed. kV CTDI_w for 'Head', 'Thorax', 'Pelvis' and 'Image Gently' (in CTDI_Φ16cm/CTDI_Φ32cm phantoms, respectively) protocols were measured as 4.5 mGy, 5.4 mGy, 19.3 mGy, and 1.1 mGy/0.5 mGy, respectively. Using 'High Quality' mode, MV CTDI_w in the CTDI_Φ16cm and CTDI _Φ32cm phantoms were computed as 84.5 mGy and 63.8 mGy (imaging length = 28 cm), 68.8 mGy and 55.5 mGy (imaging length = 16 cm), respectively, which were about twice of 'Low Dose' mode. The maximum positioning deviation observed on Halcyon was 0.51 mm ('Low Dose' adult thorax), which was lower than that of standard (0.58 mm, 'Pelvis' adult pelvis) and 'Image Gently' kV CBCT (1.57 mm, adult pelvis). Accuracy of 'Image Gently' kV CBCT head & neck and thoracic imaging were clinically acceptable for adults (maximum deviation = 0.54 mm, adult thorax). Complying with Image Gently campaign, dose-efficient protocols should be used for pediatric IGRT, achieving comparable positioning accuracy on the new Halcyon MV CBCT system relative to the conventional kV CBCT.

A new ginkgo fresh plant extract increases microcirculation and radical scavenging activity in elderly patients

INTRODUCTION

The authors investigated whether a new ginkgo biloba (ginkgo) fresh plant extract had a positive effect on microcirculation in the skin and liver of elderly individuals, and whether the extract had antioxidative properties in vivo.

METHODS

In a monocentric, controlled clinical trial with 32 elderly patients, 16 patients received three 90 mg ginkgo extract tablets twice daily for 30 days, and 16 patients acted as untreated controls. On days 0, 10, 20, and 30, microcirculatory parameters were measured using intravital microscopy in combination with reflection spectrometry, and the amount of reduced glutathione in the liver.

RESULTS

This new ginkgo fresh plant extract significantly increased the number of blood cell-perfused nodal points, the venular streaming flow, and the local hematocrit in treated participants compared to control participants and compared to values on day 0. The ginkgo preparation also increased microcirculation in the liver, and possessed antioxidative properties that resulted in significant increases in the amount of the radical scavenger glutathione in treated participants.

CONCLUSION

The new ginkgo fresh plant extract increased the microcirculation significantly, and at the same time improved the radical scavenging capacity in elderly patients and was very well tolerated. This extract is an interesting adjuvant treatment option for patients suffering from impaired microcirculation and improves mechanisms which inhibit an accelerated expression of atherosclerosis.

Effect of Ginkgo biloba extract (GbE-761) on the survival of fasciocutaneous flaps in rats

Cutaneous and fasciocutaneous flaps are used widely in the surgical reconstruction of various body segments, especially to cover exposed vital tissues. Partial or total necrosis of these flaps, secondary to insufficient tissue irrigation, is one possible complication. Therefore, investigations into antiplatelet aggregation, vasodilation and antioxidant properties are highly significant. The aim of the present study was to analyse the effect of GbE 761 on the survival of fasciocutaneous flaps in rats. For that purpose, GbE 761 was administered to 30 rats after the creation of 10 × 3 cm dorsal flaps on each animal. The rats were divided into three equal groups. GbE 761 was administered to Group A, starting immediately after surgery; Group B received it 24 h after the flap was cut; and Group C (controls) received 0.9% NaCl solution. The average area of necrosis was 29.53% in Group A, 26.25% in Group B and 46.12% in Group C. The difference between Groups B and C was statistically significant (p = 0.026). These initial findings suggest that GbE 761 administered on day 1 after surgery reduces the percentage of necrosis in fasciocutaneous flaps, relative to not giving GbE at all.

Involvement of P-glycoprotein in regulating cellular levels of Ginkgo flavonols: quercetin, kaempferol, and isorhamnetin

Quercetin, kaempferol, and isorhamnetin were the most important flavonoid constituents in extracts from Ginkgo biloba leaves. Transport studies of Ginkgo flavonols were performed in Caco-2 cell mono-layers. Their apparent permeability in absorptive and secretion directions was determined, and quercetin, kaempferol and isorhamnetin displayed polarized transport, with the Papp,B-A being higher than the Papp,A-B (P &lt; 0.01 for quercetin, P &lt; 0.001 for kaempferol and isorhamnetin, Student's t-test). Bcap37/MDR1 cells, which were transfected with a P-glycoprotein (P-gp) gene construct, were treated with quercetin, kaempferol or isorhamnetin. The concentrations of Ginkgo flavonol in Bcap37/MDR1 cells were lower than those in parent cells (P &lt; 0.05 for quercetin, P &lt; 0.01 for isorhamnetin, Mann-Whitney U test). The concentrations of the flavonol in transfected cells increased when incubated with the P-gp inhibitor verapamil (P &lt; 0.05 for kaempferol, Mann-Whitney U test). A colorometric assay for ATPase activity was applied to the detection of interaction of flavonol with P-gp. Quercetin and kaempferol inhibited the ATPase activity, and isorhamnetin stimulated the ATPase activity (P &lt; 0.05 for isorhamnetin, Mann Whitney U test). The results indicated that Ginkgo flavonols quercetin, kaempferol and isorhamnetin were substrates of P-gp. The P-gp type efflux pump might limit the bioavailability of Ginkgo flavonols.

Ginkgo Biloba Extract EGb 761 Alleviates Hepatic Fibrosis and Sinusoidal Microcirculation Disturbance in Patients with Chronic Hepatitis B

Background

Few clinical data are available regarding the effect of Ginkgo biloba extract (EGb 761) on liver microcirculation and fibrosis. This randomized, controlled trial is to investigate the effect of Ginko biloba extract EGb 761 on liver fibrosis and hepatic microcirculation in patients with chronic hepatitis B.

Methods

Sixty-four patients with chronic hepatitis B were randomized for intention-to-treat. Thirty-two patients were assigned to treated group receiving EGb 761 plus polyunsaturated phosphatidylcholine (Essentiale), 32 patients received Essentiale as controls. Blood samples were taken for measurement of transforming growth factor beta-1 (TGF-β1), platelet activate factor (PAF), endothelin 1 (ET-1). Twenty-six patients in treated group and 21 patients in control group underwent liver biopsies for histology before and after treatment. Ultrastructural study for sinusoidal microcirculation before and after treatment was carried out on 10 randomly selected patients in each group.

Results

In the treated group, after EGb 761 treatment, there was a significant reduction of blood TGF- β1, PAF and ET-1 (p<0.05), whereas this was not observed in the controls. After treatment in both groups, there were significant decrease of ALT, TBil and PT (p<0.05), and significant increase of ALB (p<0.05). Hepatic inflammation and fibrosis significantly alleviated in the treated group, but not in the controls. After EGb 761 treatment, electron microscopy showed red blood cell aggregates and microthrombosis disappeared or decreased in sinusoids; collagen deposits in sinusoidal lumen and Disse space reduced; sinusoidal capillarization alleviated.

Conclusions

EGb 761 can improve sinusoidal microcirculation, alleviate inflammation and inhibit fibrosis through multiple mechanisms, it is effective in the treatment of chronic liver diseases.

Ginkgo biloba extract improves coronary artery circulation in patients with coronary artery disease: contribution of plasma nitric oxide and endothelin-1

In patients with coronary artery disease (CAD), coronary blood flow is usually impaired due to imbalanced vasoactive substances such as nitric oxide (NO) and endothelin-1 (ET-1). The study was designed to test the effects of Ginkgo biloba extract (GBE) on the distal left anterior descending coronary artery (LAD) blood flow and plasma NO and ET-1 levels. Eighty CAD patients were randomly assigned to GBE (n = 42) and control (n = 38) groups. The LAD blood flow was assessed non-invasively using Doppler echocardiography at baseline and after 2 weeks. GBE treatment demonstrated a significant improvement in maximal diastolic peak velocity (MDPV), maximal systolic peak velocity (MSPV) and diastolic time velocity integral (DTVI) compared with controls (14.61 +/- 4.51% vs 0.67 +/- 2.66%, 9.03 +/- 4.81% vs 0.34 +/- 2.67% and 14.69 +/- 5.08% vs 0.68 +/- 3.00%, respectively, p < 0.01). NO was increased by 12.42% (p < 0.01), whereas ET-1 was decreased by 5.82% (p < 0.01). The NO/ET-1 ratio was increased by 19.47% (p < 0.01). A linear correlation was confirmed between the percentage change in LAD blood flow and in NO, ET-1 or NO/ET-1 ratio following GBE treatment. The results suggest that GBE treatment in CAD patients led to an increase of LAD blood flow, which might at least be related partly to the restoration of the delicate equilibrium between NO and ET-1.

Ginkgo biloba extract improves coronary blood flow in healthy elderly adults: role of endothelium-dependent vasodilation

Advancing age decreases endothelial function; accordingly, it alters the physiological regulation of coronary blood flow. Ginkgo biloba extract (GBE) has well-documented anti-ageing effects. However, little is yet known about the pharmacological actions of GBE on endothelial dysfunction and coronary blood flow in healthy elderly adults. We designed the study to test the effects of GBE on distal left anterior descending coronary artery (LAD) blood flow and endothelium-dependent brachial artery flow-mediated dilation (FMD) in healthy elderly adults. Sixty healthy elderly adults were randomly assigned to either GBE or control groups. LAD blood flow and brachial artery FMD were measured non-invasively using high-resolution ultrasound before and after intravenous administration of GBE or saline. GBE significantly increased LAD blood flow in maximal diastolic peak velocity (MDPV), maximal systolic peak velocity (MSPV) and diastolic time velocity integral (DTVI) compared with the placebo group (19.16+/-13.91% vs. 0.30+/-2.55%, 17.76+/-14.56% vs. 0.53+/-2.32%, and 21.73+/-16.13% vs. 0.81+/-2.33%, MDPV, MSPV, and DTVI improvement from baseline, respectively, p<0.01). Brachial artery FMD was also increased by 56.03% (from 7.21+/-2.52% to 11.28+/-3.95%, p<0.01). A linear correlation was found between the percentage change in MDPV, MSPV, or DTVI of LAD blood flow and the percentage change in brachial artery FMD following treatment with GBE (r=0.538, 0.366, or 0.573, respectively, p<0.01, p<0.05, or p<0.01). Our data demonstrate that GBE treatment in healthy elderly adults leads to the increase of LAD blood flow in MDPV, MSPV and DTVI, and the increased response might relate to the improved endothelium-dependent vasodilatory capacity. This study implies an important future therapeutic strategy of using GBE to counteract the detrimental effects of ageing.

Ginkgo biloba extract protects against mercury(II)-induced oxidative tissue damage in rats

Mercury(II) is a highly toxic metal which induces oxidative stress in the body. In this study we aimed to investigate the possible protective effect of Ginkgo biloba (EGb), an antioxidant agent, against experimental mercury toxicity in rat model. Following a single dose of 5mg/kg mercuric chloride (HgCl(2); Hg group) either saline or EGb (150mg/kg) was administered for 5days. After decapitation of the rats trunk blood was obtained and the tissue samples from the brain, lung, liver, and kidney were taken for the determination of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and collagen contents. Formation of reactive oxygen species in the tissue samples was monitored by chemiluminescence (CL) technique. BUN, creatinin, ALT, and AST levels and tumor necrosis factor-alpha (TNF-alpha) and lactate dehydrogenase (LDH) activity were assayed in serum samples. The results revealed that HgCl(2) induced oxidative damage caused significant decrease in GSH level, significant increase in MDA level, MPO activity and collagen content of the tissues. Treatment of rats with EGb significantly increased the GSH level and decreased the MDA level, MPO activity, and collagen contents. Similarly, serum ALT, AST and BUN levels, as well as LDH and TNF-alpha, were elevated in the Hg group as compared to control group. On the other hand, EGb treatment reversed all these biochemical indices. Our results implicate that mercury-induced oxidative damage in brain, lung, liver, and kidney tissues protected by G. biloba extract, with its antioxidant effects.

Protective effects of Gingko biloba on thioacetamide-induced fulminant hepatic failure in rats

Gingko biloba (GB) has antioxidant and platelet-activating factor (PAF) antagonistic effects. We investigated the protective effects of GB on thioacetamide (TAA)-induced fulminant hepatic failure in rats. Fulminant hepatic failure was induced in treatment groups by three intraperitoneal (ip) injections of TAA (350 mg/kg) at 24-hour intervals. Treatments with GB (100 mg/kg per day, orally) and N-acetylcysteine (20 mg/kg twice daily, sc) were initiated 48 hours prior to TAA administration. The liver was removed for histopathological examinations. Serum and liver thiobarbituric acid-reactive substance (TBARS) levels were measured for assessment of oxidative stress. Liver necrosis and inflammation scores and serum and liver TBARS levels were significantly higher in the TAA group compared to the control group (P < 0.001, < 0.001, 0.001, < 0.001, respectively). Liver necrosis and inflammation scores and liver TBARS levels were significantly lower in the GB group compared to the TAA group (P < 0.001, < 0.001 and 0.01, respectively). GB ameliorated hepatic damage in TAA-induced fulminant hepatic failure. This may be due to the free radical-scavenging effects of GB.

Roles of activin A and hepatocellular apoptosis in the anti-liver fibrosis process induced by Ginkgo biloba extract in rats

AIM: To investigate the effects of Ginkgo biloba extract (GBE) on CCl₄-induced liver fibrosis as well as the underlying mechanisms.

METHODS: Thirty adult male Sprague Dawley rats were randomized into 3 groups: control group (n = 10), model group (n = 10) and treatment group (n = 10). Except the rats in the control group, the others were intraperitoneally injected with 500 mL/L CCl₄ (1 mL/kg) to induce liver cirrhosis (twice a week, for 8 weeks). Moreover, the rats in treatment group were intragastrically administered with GBE (0.4 g/kg) for 8 weeks. At the end of the 8^th week, all the rats were sacrificed. Blood samples were collected for the determination of biochemical indicators. Tissue samples were used for histopathological examinations. The expression of activin A was determined by immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR). Hepatocellular apoptosis was determined by the method of terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) method.

RESULTS: The grade of liver fibrosis in treatment group was lower than that in the model group (P < 0.05). The serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and albumin (ALB) in treatment group were significantly improved as compared with those in the model group (ALT: 2806.9 ±576.1 nkat/L vs 4452.9 ± 709.5 nkat/L; AST: 5314.2 ± 1042 nkat/L vs 15 743.4 ± 625.8 nkat/L; ALB: 31.0 ± 2.1 g/L vs 21.7 ± 1.8 g/L; all P < 0.05). GBE treatment markedly reduced mRNA and protein levels of activin A (mRNA: 0.42 ± 0.09 vs 0.78 ± 0.15; protein: 4.2 ± 0.8 vs 11.4 ± 1.2; both P < 0.01). In comparison with that in the model group, the apoptosis index was decreased in treatment groups (7.56 ± 3.36 vs 16.06 ± 8.84, P < 0.01).

CONCLUSION: GBE can markedly attenuate the degrees of hepatic fibrosis, and the mechanism may be correlated with the expression of activin A and hepatocellular apoptosis.

Effects of extract from Ginkgo biloba on carbon tetrachloride-induced liver injury in rats

AIM: To study the effects of extract from Ginkgo biloba (EGb) containing 22% flavonoid and 5% terpenoid on chronic liver injury and liver fibrosis of rats induced by carbon tetrachloride (CCl₄).

METHODS: All rats were randomly divided into control group, CCl₄-treated group, colchicine-treated group and EGb-protected group. Chronic liver injury was induced in experimental groups by subcutaneous injection of CCl₄ and fed with chows premixed with 79.5% corn powder, 20% lard and 0.5% cholesterol (v/v). EGb-protected group was treated with EGb (0.5 g/kg body weight per day) for 7 wk. At the end of wk 8, all the rats were killed. Liver function, liver fibrosis, oxidative stress and expression of transforming growth factor β₁ (TGF-β₁), a-smooth muscle actin (α-SMA) and type I collagens in liver were determined. In addition, pathology changes of liver tissue were observed under light microscope.

RESULTS: The levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and albumin (Alb) in EGb-protected group were notably improved as compared with the CCL₄-treated group (P < 0.01). The contents of serum hyaluronic acid (HA), type III procollagen (PCIII), type IV collagen (CIV) and the expression of hepatic tissue TGF-β₁, α-SMA and type I collagen in EGb-protected group were significantly lower than those in CCL₄-treated groups (P < 0.05, P < 0.01). The degrees of liver fibrosis in EGb-protected groups were lower than those in CCL₄-treated groups (6.58 ± 1.25 vs 9.52 ± 2.06, P < 0.05). Compared to the CCL₄-treated group, the levels of plasma glutathoine peroxidase (Se-GSH-Px), superoxide dismutase (SOD) and malondialdehyde (MDA) were strikingly improved also in EGb-protected group (P < 0.05, P < 0.01).

CONCLUSION: EGb resists oxidative stress and thereby reduces chronic liver injury and liver fibrosis in rats with liver injury induced by CCl₄.

Protective effects of ginkgo biloba against acetaminophen-induced toxicity in mice

BACKGROUND

The analgesic acetaminophen (AAP) causes a potentially fatal, hepatic centrilobular necrosis when taken in overdose. It was reported that these toxic effects of AAP are due to oxidative reactions that take place during its metabolism.

OBJECTIVE

In this study, we aimed to investigate the possible beneficial effect of Ginkgo biloba (EGb), an antioxidant agent, against AAP toxicity in mice.

METHODS

Balb/c mice were injected i.p. with: (1) vehicle, control (C) group; (2) a single dose of 50 mg/kg Ginkgo biloba extract, EGb group; (3) a single dose of 900 mg/kg i.p. acetaminophen, AAP group, and (4) EGb, in a dose of 50 mg/kg after AAP injection, AAP + EGb group. Serum ALT, AST, and tumor necrosis factor-alpha (TNF-alpha) levels in blood and glutathione (GSH), malondialdehyde (MDA) levels, myeloperoxidase (MPO) activity, and collagen contents in liver tissues were measured. Formation of reactive oxygen species in hepatic tissue samples was monitored by using chemiluminescence (CL) technique with luminol and lusigenin probe. Tissues were also examined microscopically.

RESULTS

ALT, AST levels, and TNF-alpha were increased significantly (p < 0.001) after AAP treatment, and reduced with EGb. Acetaminophen caused a significant (p < 0.05-0.001) decrease in GSH levels while MDA levels and MPO activity were increased (p < 0.001) in liver tissues. These changes were reversed by EGb treatment. Furthermore, luminol and lusigenin CL levels in the AAP group increased dramatically compared to control and reduced by EGb treatment (p < 0.01).

CONCLUSION

Our results implicate that AAP causes oxidative damage in hepatic tissues and Ginkgo biloba extract, by its antioxidant effects protects the tissues. Therefore, its therapeutic role as a "tissue injury-limiting agent" must be further elucidated in drug-induced oxidative damage.

Ginkgo biloba extract reduces naphthalene-induced oxidative damage in mice

This investigation elucidated the role of free radicals in naphthalene-induced toxicity and protection by Ginkgo biloba extract (EGb). BALB-c mice of either sex were administered with naphthalene (100 mg/kg; i.p.) for 30 days, along with either saline or EGb (150 mg/kg, orally). At the end of the experiment, following decapitation, lung, liver and kidney tissue samples were taken for histological examination or determination of malondialdehyde (MDA), glutathione (GSH), myeloperoxidase (MPO) activity and collagen contents. In addition, proinflammatory cytokines (TNF-alpha and IL-beta) and total antioxidant capacity (AOC) were assayed in the plasma, while lactate dehydrogenase (LDH) activity was assayed in serum samples. The results revealed that naphthalene caused a significant decrease in GSH level, and significant increases in MDA level, MPO activity and collagen content of tissues. Similarly, plasma cytokines, as well as serum LDH activity, were elevated while AOC was decreased in the naphthalene group compared with the control group. On the other hand, EGb treatment reversed all these biochemical indices. The results demonstrate that EGb extract, by balancing the oxidant-antioxidant status and inhibiting the generation of proinflammatory cytokines and neutrophil infiltration, protects against naphthalene-induced oxidative organ injury.

Ginkgo biloba extract alleviates liver fibrosis induced by CCl in rats

AIMS

To investigate the protective effect of Ginkgo biloba extract (GbE) on liver fibrosis induced by carbon tetrachloride (CCl4) in rats and expressions of transforming growth factor beta1 (TGF-beta1) and collagen I during this period.

METHODS

The effect of GbE on liver fibrogenesis was detected by hematoxylin and eosin staining (H&E staining), Masson's trichrome staining, and electron microscope study. Blood samples were collected for measurement of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and albumin. Malondialdehyde (MDA) in liver tissue was detected by the thiobarbituric acid (TBA) method. Immunohistochemistry assay and RT-PCR were used to examine the protein expressions and mRNA levels of TGF-beta1 and collagen I, respectively.

RESULTS

H&E, Masson's trichrome stainings and electron microscope study showed liver fibrosis in rats was greatly alleviated when treated with GbE. Additionally, there was a remarkable improvement of serum ALT, AST, albumin and MDA in the GbE-treated group. Immunohistochemistry and RT-PCR results showed GbE intervention significantly inhibited TGF-beta1 and collagen I expressions in rat liver. No side effects of GbE were found during these experiments. But GbE could not reverse the pathological changes of liver fibrosis completely when compared with normal control.

CONCLUSION

GbE can partially protect rat liver from the fibrogenesis induced by CCl4. The mechanism may lie in its effect of inhibiting oxidative stress caused by liver injury and expressions of signal molecules such as TGF-beta1. GbE may thus be of potential help as a medicament or food additive for alleviation of liver fibrogenesis.

Simultaneous determination of quercetin, kaempferol and isorhamnetin accumulated human breast cancer cells, by high-performance liquid chromatography

Quercetin, kaempferol and isorhamnetin are the most important constituents in ginkgo flavonoids. A simple, rapid and sensitive high-performance liquid chromatography method was developed to simultaneously determine quercetin, kaempferol and isorhamnetin absorped by human breast cancer cells. Cells were treated with ginkgo flavonols and then lysed with Triton-X 100. The flavonols in the samples were measured by RP-HPLC with a C18 column after a simple extraction with a mixture of ether and acetone. The mobile phase contained phosphate buffer (pH 2.0; 10 mM) tetrahydrofuran, methanol and isopropanol (65:15:10:20, v/v/v/v). The ultraviolet detector was operated at 380 nm. The calibration curve was linear from 0.1 to 1.0 microM (r > 0.999) for each flavonol. The mean extraction efficiency was about 70%. The recovery of the assay was between 98.9 and 100.6%. The limit of detection was 0.01 microM for quercetin and kaempferol and 0.05 microM for isorhamnetin. The limit of quantitation was 0.1 microM (R.S.D.<10%) for each flavonol. The intra- and inter-day coefficients of variation were less than 10% (R.S.D.). The validated method was applied to quantify quercetin, kaempferol and isorhamnetin in human breast cancer Bcap37 and Bcap37/MDR1 cells.

5-Fluorouracil catabolism to 5-fluoro-5,6-dihydrouracil is reduced by acute liver impairment in mice

This study investigated the effect of acute liver damage on the inactivation of 5-fluorouracil (5-FU) to its main catabolite 5-fluoro-5,6-dihydrouracil (5-FUH2) in mice. Plasma pharmacokinetics of 5-FU and 5-FUH2 in mice receiving 5-FU (10, 30, and 90 mg/kg) were compared to those in mice pretreated with carbon tetrachloride and receiving the same 5-FU doses. Carbon tetrachloride-induced hepatic damage was histopathologically examined under light microscopy and serum transaminases and dihydropyrimidine dehydrogenase activities were also measured. Liver histopathology and elevated aminotransferase activity levels confirmed the presence of liver damage. 5-FU C(max) and AUC both increased up to 71% in mice with liver damage. This was reflected by decreased 5-FUH2 production, since 5-FUH2 C(max) and AUC levels decreased up to 47% and 61%, respectively. Metabolic ratios between 5-FUH2 and 5-FU AUCs were considerably decreased as well, further suggesting that liver damage caused a reduction in 5-FU catabolism. DPD activity was not altered in damaged livers. The present results indicate that 5-FU disposition in mice could be profoundly altered in the presence of severe liver impairment, potentially leading to enhanced anabolic activation of 5-FU. This effect seems to be ascribed to a reduction of viable hepatocytes, rather than to an inactivation of DPD activity.