Antioxidant Extract from Cleistocalyx nervosum var. paniala Pulp Ameliorates Acetaminophen-Induced Acute Hepatotoxicity in Rats

The indigenous purplish red fruit, Cleistocalyx nervosum var. paniala (CN), is grown in northern Thailand. The aqueous extract of CN pulp is known to exhibit antioxidant and anticarcinogenic properties. To search for an antioxidant fraction separated from CN, various hydroalcoholic extractions were performed. The acidified ethanolic extract of CN obtained from 0.5% (v/v) citric acid in 80% (v/v) ethanol yielded greater polyphenol content and DPPH radical scavenging activity when compared with other hydroethanolic extracts. Cyanidin-3-glucoside is a major anthocyanin present in the acidified ethanolic extract of CN (AECN). At a dose of 5000 mg/kg bw, an anthocyanin-rich extract was found to be safe when given to rats without any acute toxicity. To examine the hepatoprotective properties of AECN, an overdose of acetaminophen (APAP) was induced in a rat model, while silymarin was used as a standard reference. The administration of AECN at a dose of 300 mg/kg bw for 28 days improved hepatocyte architecture and modulated serum alanine aminotransferase levels in APAP-induced rats. Furthermore, it significantly decreased serum and hepatic malondialdehyde levels but increased hepatic glutathione content, as well as glutathione peroxidase and UDP-glucuronosyltransferase activities. In conclusion, AECN may effectively reduce oxidative stress induced acute hepatotoxicity in overdose APAP-treated rats through the suppression of oxidative stress and the enhancement of the antioxidant system in rat livers.

Twin drug design, synthesis and evaluation of diosgenin derivatives as multitargeted agents for the treatment of vascular dementia

A novel series of multitargeted molecules were designed and synthesized by combining the pharmacological role of cholinesterase inhibitor and antioxidant of steroid as potential ligands for the treatment of Vascular Dementia (VD). The oxygen-glucose deprivation (OGD) model was used to evaluate these molecules, among which the most potent compound ML5 showed the highest activity. Firstly, ML5 showed appropriate inhibition of cholinesterases (ChEs) at orally 15 mg/kg in vivo. The further test revealed that ML5 promoted the nuclear translocation of Nrf2. Furthermore, ML5 has significant neuroprotective effect in vivo model of bilateral common carotid artery occlusion (BCCAO), significantly increasing the expression of Nrf2 protein in the cerebral cortex. In the molecular docking research, we predicted the ML5 combined with hAChE and Keap1. Finally, compound ML5 displayed normal oral absorption and it was nontoxic at 500 mg/kg, po, dose. We can draw the conclusion that ML5 could be considered as a new potential compound for VD treatment.

A review of the processed Polygonum multiflorum (Thunb.) for hepatoprotection: Clinical use, pharmacology and toxicology

ETHNOPHARMACOLOGICAL RELEVANCE

Polygonum multiflorum (Thunb.) (PMT) is a member of Polygonaceae. Traditional Chinese medicine considers that the processed PMT can tonify liver, nourish blood and blacken hair. In recent years, the processed PMT and its active ingredients have significant therapeutic effects on nonalcoholic fatty liver disease, alcoholic fatty liver disease, viral hepatitis, liver fibrosis and liver cancer.

AIM OF THE STUDY

The main purpose of this review is to provide a critical appraisal of the existing knowledge on the clinical application, hepatoprotective pharmacology and hepatotoxicity, it provides a comprehensive evaluation of the liver function of the processed PMT.

MATERIALS AND METHODS

A detailed literature search was conducted using various online search engines, such as Pubmed, Google Scholar, Mendeley, Web of Science and China National Knowledge Infrastructure (CNKI) database. The main active components of the processed PMT and the important factors in the occurrence and development of liver diseases are used as key words to carry out detailed literature retrieval.

RESULTS

In animal and cell models, the processed PMT and active components can treat various liver diseases, such as fatty liver induced by high-fat diet, liver injury and fibrosis induced by drugs, viral transfected hepatitis, hepatocellular carcinoma, etc. They can protect liver by regulating lipid metabolism related enzymes, resisting insulin resistance, decreasing the expression of inflammatory cytokines, inhibiting the activation of hepatic stellate cells, reducing generation of extracellular matrix, promoting cancer cell apoptosis and controlling the growth of tumor cells, etc. However, improperly using of the processed PMT can cause liver injury, which is associated with the standardization of processing, the constitution of the patients, the characteristics of the disease, and the administration of dosage and time.

CONCLUSION

The processed PMT can treat various liver diseases via reasonably using, and the active compounds (2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside, emodin, physcion, etc.) are promising candidate drugs for developing new liver protective agents. However, some components have a "toxic-effective" bidirectional effect, which should be used cautiously.

A review of Penthorum chinense Pursh for hepatoprotection: Traditional use, phytochemistry, pharmacology, toxicology and clinical trials

ETHNOPHARMACOLOGICAL RELEVANCE

In China, Penthorum chinense Pursh (P. chinense) has been used for hundreds of years traditionally for alleviating symptoms by excessive intake of alcohol as well as in the treatment of traumatic injury, edema and liver diseases. Recently, P. chinense and its extract have been developed into tea, drinks or medicines for treatment of liver diseases, including hepatic virus infections, alcoholic liver disease (ALD), non-alcoholic fatty liver disease (NAFLD) and liver fibrosis.

AIM OF THE STUDY

The main purpose of this review is to provide a critical appraisal of the existing knowledge on the phytochemical data, quality control aspect, pharmacological, as well as toxicological and clinical studies performed on P. chinense, including the identification of scientific gaps.

MATERIALS AND METHODS

A detailed literature search was conducted using various online search engines, such as Pubmed, Scopus, Google Scholar, Mendeley, Web of Science as well as China National Knowledge Infrastructure (CNKI) database.

RESULTS

In the pharmacological studies, there clearly are links between local/traditional uses and the biomedical investigations. Most pharmacological studies indicated potential liver protective effects in experimental models of chemicals-induced liver injury, acute and chronic alcoholic liver injury, NAFLD, liver fibrosis and viral infection, potentially through antioxidant effects, balancing key liver enzyme levels, inhibition of hepatic virus DNA replication, inhibition of hepatic stellate cells activation and inflammation either in vitro or in vivo. In some models, the effects of P. chinense is comparable with the one of silymarin. Clinical studies have suggested that P. chinense is safe and effective in treating several liver diseases, although most of them are not double-blinded and placebo-controlled studies. Toxicology studies show that P. chinense has no obvious toxicity or side effects in animals or human. Flavonoids, lignans, coumarins, polyphenols and organic acids have been identified. However, only a few studies have investigated the active compounds (mainly flavonoids and lignans) and molecular mechanisms of P. chinense.

CONCLUSION

P. chinense seems to be safe and shows relevant liver protecting effects. Therefore, it might be a promising candidate for developing as new hepatoprotective agents. However, a lack of understanding of the active compounds and mechanisms of action needs further attention.

In vivo hepatoprotective and In vitro radical scavenging activities of Cucumis ficifolius A. rich root extract

ETHNOPHARMACOLOGICAL RELEVANCE

Cucumis ficifolius A. Rich is a perennial prostrate herb that stems up to 1 m long. Its root is widely used in traditional medicine to treat various diseases including liver diseases. Yet, scientific evidence is lacking to verify its ethno medicinal claims.

AIM OF THE STUDY

The present study was conducted to assess the hepatoprotective and radical scavenging activity of 80% methanol crude extract and different fractions of Cucumis ficifolius root.

MATERIALS AND METHODS

Radical scavenging activity was done applying the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay while hepatoprotective activity was assessed using pre- and post-treatment models of carbon tetrachloride (CCl₄)-induced liver injury in Swiss albino mice of either sex weighing 25-30 g. A single oral dose of 2000 mg/kg was used for acute toxicity study, doses of 125, 250, and 500 mg/kg were used in the pre-treatment model, and 500 mg/kg of extract and chloroform fraction were used in the post-treatment model. Biochemical markers and histopathological parameters were used to measure hepatoprotective activities.

RESULTS

C. ficifolius crude extract and its solvent fractions showed strong radical scavenging activity and the chloroform fraction had the highest activity. No sign of toxicity was shown in an acute toxicity test of the extract. Hepatoprotective activity evaluation on the crude extract by a pre-treatment model with 125, 250, and 500 mg/kg doses revealed a significant (p < 0.05) reduction of the serum level of CCl₄-induced liver enzyme markers at the highest tested dose (500 mg/kg). The chloroform fraction that had highest radical scavenging activity and the crude extract, both at 500 mg/kg, were again evaluated in a post-treatment model and the results revealed that both the extract and the chloroform fraction demonstrated significant (p < 0.05) hepatoprotective activities which support the results of the pre-treatment model.

CONCLUSION

The present study verified the hepatoprotective potentials of C. ficifolius extract and its chloroform fraction which might be, at least in part, through radical scavenging action.

Crocus sativus by-products as sources of bioactive extracts: Pharmacological and toxicological focus on anthers

Multiple studies revealed the potential application of high quality saffron byproducts as cheap sources of bioactive compounds endowed with antioxidant activity. In the present study, we analyzed the total fatty acids of the anthers, and explored the pharmacological and toxicological potential of anthers, by evaluating genotoxic and protective effects in multiple cell lines, brine shrimps and isolated rat tissues. The phytochemical analyses showed that anthers are rich in long chain fatty acids most of which are unsaturated (80.51%). Particularly, anther water extract revealed to be well tolerated by multiple cell lines, and able to modulate reactive oxygen species (ROS) levels, without exerting either genotoxic or cytotoxic effects. The same extract was also able to blunt lipopolysaccharide (LPS)-induced nitrite and malondialdehyde (MDA) in isolated rat tissues. On the other hand, considering the concomitant null effect on HCT116 cell migration, in wound healing experimental paradigm, our findings suggest the efficacy of water anther extract as protective agent without any direct reverting effects on lesioned tissues. Concluding, the promising results, deriving from the pharmacological and toxicological evaluations, support the valorization of saffron anthers as a strategy to optimize and develop the productive chain of Abruzzo saffron.

Effects of histatin-1 peptide on human corneal epithelial cells

Purpose

Ocular surface and corneal epithelial wounds are common and potentially debilitating problems. Ideal treatments for these injuries would promote epithelial healing without inflammation, infection and scarring. In addition the best treatments would be cost-efficient, effective, non-toxic and easily applied. Histatin-1 peptides have been shown to be safe and effective enhancers of epithelial wound healing in other model systems. We sought to determine whether histatin-1 peptides could enhance human corneal epithelial wound healing in vitro.

Methods

Histatin-1 peptides were applied to human corneal epithelial cells and compared over useful dose ranges in scratch assays using time-lapse microscopy. In addition, path finding analysis, cell spreading assays, toxicity and proliferation assays were performed to further characterize the effects of histatin-1 peptide on human corneal limbal epithelial (HCLE).

Results

Histatin-1 enhanced human corneal epithelial wound healing in typical wound healing models. There was minimal toxicity and no significant enhancement of proliferation of corneal epithelium in response to histatin-1 application. Corneal epithelial spreading and pathfinding appeared to be enhanced by the application of histatin-1 peptides.

Conclusions

Histatin -1 peptide may enhance migration of HCLE cells and wound healing in vitro. These peptides may have benefit in corneal epithelial wounds and need to be investigated further.

A low level of dietary selenium has both beneficial and toxic effects and is protective against Cd-toxicity in the least killifish Heterandria formosa

As an essential element, selenium (Se) is beneficial at low levels yet toxic at high levels. The present study assessed the effects of dietary exposure to Se in the least killifish Heterandria formosa, and investigated how this exposure influences the effects of a subsequent exposure to cadmium (Cd). The fish were pre-exposed to an environmentally relevant concentration (2 μg g(-1) dry wt) of dietary selenite (Se(4+)) or seleno-l-methionine (Se-Met) for 10 d. The same fish were then exposed to 0.5 mg L(-1) of Cd for 5 d. Both Se(IV) and Se-Met rapidly accumulated in H. formosa. Results for the two Se species were generally similar in this study. Fish exposed to Se had lower levels of lipid peroxidation (measured as levels of thiobarbituric acid reactive substances or TBARS) and a higher catalase (CAT) activity. In contrast, their Na(+)/K(+)-ATPase activity was reduced. The Cd exposure resulted in an increase in lipid peroxidation and decreases in the activities of catalase and Na(+)/K(+)-ATPase. The Cd-exposed H. formosa that were pre-exposed to Se had lower Cd body burdens, less lipid peroxidation, and higher catalase activity, than did fish not pre-exposed to Se. The Se exposure did not have a protective effect on the Cd-induced reduction in Na(+)/K(+)-ATPase activity. These results clearly demonstrate that a Se-enriched diet reduces some (but not all) forms of Cd-toxicity and that Se can simultaneously have beneficial and detrimental effects, making it difficult to predict the net outcome of changes in dietary Se levels for fish.

Gastroprotective effects and antimicrobial activity of Lithraea molleoides and isolated compounds against Helicobacter pylori

ETHNOPHARMACOLOGICAL RELEVANCE

Lithraea molleoides (Vell.) Engl. (Anacardiaceae) is a medicinal plant traditionally used in South America to treat various ailments, including diseases of the digestive system.

AIM OF THE STUDY

To evaluate the in vivo antiulcer and antimicrobial activities against Helicobacter pylori of L. molleoides and its isolated compounds.

MATERIALS AND METHODS

Methanolic extract 250 and 500 mg/kg, (LmE 250 and LmE 500, respectively) and infusions, 10 g and 20 g en 100mL (LmI 10 and LmI 20, respectively) of L. molleoides was evaluated for antiulcer activity against 0.6N HCl, 0.2N NaOH, 200mg/kg acetilsalicilic acid and absolute ethanol-induced gastric ulcers in rats. The degree of erosion in the glandular part of the stomach was assessed from a scoring system. Acute toxicity in mice was also evaluated. The antiulcer effect of the isolated compounds (catechol, mannitol, rutin, gallic acid, ferulic acid and caffeic acid, 100mg/kg) was evaluated against absolute ethanol-induced gastric ulcers in rats. The anti-Helicobacter pylori activity of L. molleoides and isolated compounds was performed using broth dilution methods.

RESULTS

The LmE 250, LmE 500, LmI 10 and LmI 20 produced significant inhibition on the ulcer index in 0.6N HCl, 0.2N NaOH, 200mg/kg acetilsalicilic acid and absolute ethanol- induced gastric ulcers in rats. The isolated compounds, catechol, mannitol, rutin, ferulic acid and caffeic acid were active in absolute ethanol- induced gastric ulcers in rats. L. molleoides and different compounds showed antimicrobial activity in all strains tested. The lowest MIC value (0. 5 μg/mL) was obtained with catechol in six of eleven strains assayed. No signs of toxicity were observed with doses up to 2g/kg in an acute toxicity assay.

CONCLUSION

These findings indicate that L. molleoides displays potential antiulcerogenic and antimicrobial activities and the identification of active principles could support the use of this plant for the treatment of digestive affections.

Protective effect of Terminalia muelleri against carbon tetrachloride-induced hepato and nephro-toxicity in mice and characterization of its bioactive constituents

CONTEXT

Terminalia is used in folk medicine for the treatment of various diseases.

OBJECTIVE

The objective of this study is to investigate the hepatonephro protective activity of a polyphenol-rich fraction (TMEF) obtained from Terminalia muelleri Benth. (Combretaceae) against CCl4-induced toxicity in mice.

MATERIALS AND METHODS

TMEF was administered (100, 200, and 400 mg/kg/d) for 5 d. CCl4 was administered at the end of the experiment. Hepatic and renal biomarkers were measured in the serum. Glutathione (GSH), superoxide dismutase (SOD), and malondialdehyde (MDA) were estimated in the liver and kidney tissues. The active constituents of TMEF were identified by HPLC-PDA-ESI/MS/MS.

RESULTS

TMEF is rich in ellagitannins, galloyl esters, phenolic acids, and flavone-C-glucosides. TMEF pretreatment significantly (p < 0.001) inhibited the CCl4-induced increase in ALT (17, 43, and 53%), AST (20, 46, and 58%), ALP (20, 48, and 56%), LDH (21, 47, and 58%), hepatic MDA (23, 49, and 54%), renal MDA (22, 35, and 52%), creatinine (48, 66, and 91%), uric acid (16, 34, and 59%), urea (22, 39, and 59%), and cholesterol (20, 27, and 46%). Furthermore, TMEF administration significantly (p < 0.001) increased hepatic GSH (15, 51, and 79%), renal GSH (23, 45, and 73%), hepatic SOD (9, 52, and 95%), renal SOD (39, 66, and 85%) and protein levels (17, 24, and 29%) at the tested doses of TMEF, respectively. Pretreatment with TMEF preserved the hepatic architecture and protected from ballooning degeneration, liver necrosis, renal inflammation, and degeneration of the kidney tubules.

CONCLUSION

TMEF has a marked hepato-nephro protective effect.

New insights into the effects of formulation type and compositional mixtures on the antioxidant and cytotoxic activities of dietary supplements based-on hepatoprotective plants

Artichoke (A), borututu (B) and milk thistle (M) are included in several supplements to provide beneficial effects. Different formulations (infusions, pills and syrups), with different proportions of A, B and M (1 : 1 : 1, 2 : 1 : 1, 1 : 2: 1, 1 : 1 : 2) within each formulation, were assayed to optimize the desired benefits. The antioxidant activity, anti-hepatocellular carcinoma activity, hepatotoxicity and bioactive compound contents were evaluated. Syrups tended to be the formulation with highest antioxidant activity and total phenolic and flavonoid content; otherwise, pills were the worst formulation. In what concerns A : B : M ratios, the results did not reveal so pronounced differences. None of the assayed mixtures resulted to be toxic (up to the maximum assayed dose) for liver primary cells (PLP2), but some samples, especially infusions, showed toxicity for the hepatocellular carcinoma cell line (HepG2). With no exception, the mixtures for all formulations showed synergistic effects on antioxidant activity, when compared to the activity of single plants.

Protective effects of ginseng total saponins against hepatic ischemia/reperfusion injury in experimental obstructive jaundice rats

CONTEXT

Ginseng, the root of Panax ginseng C.A. Meyer (Araliaceae), is one of the most extensively used herbs for stroke and chronic debilitating conditions in East Asian countries. Ginsenosides (GS) are the main bioactive compounds for ginseng's efficacy, but the mechanisms have not been fully clarified.

OBJECTIVE

To investigate hepatoprotective effects of GS against ischemia/reperfusion (IR) injury in the experimental obstructive jaundice rats.

MATERIALS AND METHODS

GS was fed to cholestatic rats with IR injury daily for 6 d at a dose of 1.10 g/kg. Levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), superoxide dismutase (SOD) and malondialdehyde (MDA) were determined by colorimetric method. Apoptosis was measured quantitatively by the terminal transferase UTP nick end-labeling method. Protein expression of Bax and Bcl-2 was detected by immunohistochemistry.

RESULTS AND DISCUSSION

After intervention of GS to cholestatic rats with IR injury, the levels of activating blood flow were significantly improved, and the levels of serum ALT were decreased 1.7-times, AST decreased 1.3-times, but SOD activities were increased 1.1-times compared with those of the model rats. It could also reverse histopathological changes and inhibit IR-induced apoptosis of hepatic tissues via decrease of Bax/Bcl-2 ratio (from 2.87 ± 0.57 to 1.65 ± 0.29). Oral administration of GS in a dosage of 26.4 g/kg did not lead to toxic effects in rats.

CONCLUSION

GS attenuated the IR injury in the presence of cholestasis and could be considered for the clinical treatment of cholestasis.

Effect of safeners on damage of human erythrocytes treated with chloroacetamide herbicides

Chloroacetamides are used as pre-emergent substances for growth control of annual grasses and weeds. Since they can be harmful for crop plants, protective compounds (safeners) are used along with herbicides. So far, their effects on human blood cells have not been evaluated, and this study is the very first one devoted to this subject. We examined the harmful effects of chloroacetamides, their metabolites and safeners, used alone or in combination with herbicides, on human erythrocytes measuring the extent of hemolysis, lipid peroxidation and catalase activity. Higher impact of herbicides than their metabolites on all of the investigated parameters was found. Safeners alone did not produce any damage to erythrocytes and did not elicit any changes in oxidative stress parameters. Combination of safener with herbicide did not attenuate hemolysis of erythrocytes compared to the herbicide alone. Safeners reduced lipid peroxidation induced by herbicides, which suggest the role of safeners as antioxidants.

Nephroprotective activity of Cocculus hirsutus leaf extract in 5/6 nephrectomized rat model

BACKGROUND

Cocculus hirsutus, commonly known as broom creeper, belongs to the family Menispermaceae. It is widely used in folk medicine to treat leprosy, skin diseases, dyspepsia, etc. Hence, an effort has been made to investigate the nephroprotective potential of C. hirsutus.

METHODS

The nephroprotective activity of ethanolic C. hirsutus leaf extract (ECHE) in the 5/6 nephrectomized rat model was investigated. Different parameters like postoperative survival rate, change in body weight and levels of red blood corpuscles (RBCs), hemoglobin (Hb), triglyceride, cholesterol, creatinine, urea and uric acid were estimated in experimental rats.

RESULTS

The findings revealed the postoperative survival rate of rats in the investigated novel method to be 100%. Change in the body weight of ECHE-treated groups I and II was found to be 32 and 30 g, respectively. These values suggested that ECHE treatment normalized the elevated body weight levels in experimental rats. Furthermore, ECHE treatment normalized the decreased RBC levels and the elevated Hb, triglyceride, cholesterol, creatinine, urea and uric acid levels in experimental rats.

CONCLUSIONS

The results indicate that C. hirsutus has strong nephroprotective activity. However, further scrutiny is essential for isolation and characterization of the active components that can be employed to allay various human maladies.

Brassica nigra plays a remedy role in hepatic and renal damage

CONTEXT

Black mustard [Brassica nigra (L.) Koch] of the Brassicaceae (Cruciferae) family is commonly used as a spice and a cheap source of antimicrobial agents for bacterial infections.

OBJECTIVES

The present investigation was to demonstrate the protective effect of the methanol extract of B. nigra leaves against D-galactosamine (D-GalN)-induced hepatic and nephrotoxicity in Wistar rats.

METHODS

Activity of the methanol extract of B. nigra at doses of 200 and 400 mg/kg b.wt. against D-GalN (500 mg/kg b.wt.) induced toxicity, with silymarin used as the standard. Histological damage, activities of serum marker enzyme, hematological changes, metabolites such as bilirubin, urea, uric acid, and creatinine levels, tissue thiobarbutric acid reactive substance, enzymic and non-enzymic antioxidants and inflammatory marker enzymes such as myeloperoxidase, cathepsin D, and acid phosphatase were assessed.

RESULTS

The D-GalN-induced toxicity was evident from a significant increase (p < 0.001) in the serum and tissue inflammatory markers in toxic rats, when compared with the control (saline alone treated animals). The B. nigra pretreated groups (200 and 400 mg/kg b.wt.) showed significant (p < 0.001) reduction in the D-GalN-induced toxicity as obvious from biochemical parameters. Histopathological observations confirm the protective effect of B. nigra leaf extract by reduction in hepatic and renal tissue damage. Experimentals extract showed a similar effect as the standard.

CONCLUSIONS

The crude methanol extract of B. nigra leaf lacks inherent toxicity and exhibits hepatic and nephroprotective effects against D-GalN-induced toxicity in Wistar rats.

Prevention of acute kidney injury by tauroursodeoxycholic acid in rat and cell culture models

BACKGROUND

Acute kidney injury (AKI) has grave short- and long-term consequences. Often the onset of AKI is predictable, such as following surgery that compromises blood flow to the kidney. Even in such situations, present therapies cannot prevent AKI. As apoptosis is a major form of cell death following AKI, we determined the efficacy and mechanisms of action of tauroursodeoxycholic acid (TUDCA), a molecule with potent anti-apoptotic and pro-survival properties, in prevention of AKI in rat and cell culture models. TUDCA is particularly attractive from a translational standpoint, as it has a proven safety record in animals and humans.

METHODOLOGY/PRINCIPAL FINDINGS

We chose an ischemia-reperfusion model in rats to simulate AKI in native kidneys, and a human kidney cell culture model to simulate AKI associated with cryopreservation in transplanted kidneys. TUDCA significantly ameliorated AKI in the test models due to inhibition of the mitochondrial pathway of apoptosis and upregulation of survival pathways.

CONCLUSIONS

This study sets the stage for testing TUDCA in future clinical trials for prevention of AKI, an area that needs urgent attention due to lack of effective therapies.

Antioxidant activity and hepatoprotective effect of a polysaccharide from Bei Chaihu (Bupleurum chinense DC)

Chinese medicine plays a pivotal role in hepatoprotective treatment. In the present study, a water-soluble polysaccharide fraction (WBCP) was fractioned from the roots of Bupleurum chinense and purified by DEAE-cellulose and Surperdex 200 HR chromatography. The physicochemical properties, antioxidative and hepatoprotective activities of WBCP were evaluated in a rat model of hepatic injury caused by d-galactosamine (GalN). Hepatoprotective effect was evaluated by measuring aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) activities in the plasma of mice. Antioxidant activity was evaluated by measuring biochemical parameters in the mouse liver homogenate, such as glutathione reductase (GR), γ-glutamylcysteine synthetase (GCS), glutathione S-transferase (GST) and superoxide dismutase (SOD) activities, as well as glutathione (GSH) and thiobarbituric acid reactive substances (TBARS) levels. The results showed the oral administration of WBCP could significantly reduce the activity of AST, ALT, ALP and LDH, indicating that WBCP possesses hepatoprotective activity. Furthermore, there was general a statistically significant increase in the activities of GSH, GR, GCS, GST and SOD, and a loss in TBARS in the liver of WBCP-treated group compared with the control group. In addition, the elevated levels of pro-inflammatory cytokine tumour necrosis factor-alpha (TNF-α) in the serum of the experimental animals was significantly returned by WBCP treatment at the dose of 400 mg/kg. These results clearly demonstrated that WBCP possess promising hepatoprotective effects against GalN-induced liver damage, which may be mediated through augmentation of antioxidant defenses.

Evaluation of the liver protection and toxicity of Da-Huang-Zhe-Chong pill in rats

CONTEXT

Da-Huang-Zhe-Chong pill (DHZCP), a classical traditional Chinese formula, consists of 12 crude drugs which have been widely used with significant therapeutic effects. Some drugs in this formula have toxicities that might result in some adverse effects of DHZCP.

OBJECTIVE

The liver protection and toxicity of DHZCP were first evaluated against chronic carbon tetrachloride (CCl(4))-induced liver injury in rats.

MATERIALS AND METHODS

The rats were treated by intraperitoneal injection of 10% CCl(4) for 12 weeks. At the end of week 4, DHZCP at doses of 44 g/kg (high-dose group) and 22 g/kg (low-dose group) was intragastrically administered to CCl(4)-treated rats, once a day for four weeks. At the end of weeks 8 and 12, the general status of the rats, histopathology of liver, serum alanine aminotransaminase (ALT), aspartate aminotransaminase (AST), alkaline phosphatase (ALP) and total bilirubin (TBIL) levels were observed or determined and recorded. By correspondence analysis (CA) on biochemical markers and liver histopathological score (HS), the "dose-time-response" relationship of DHZCP on the hepatic injury rats was evaluated.

RESULTS

The results showed that DHZCP exhibited a significant protective effect on liver injury by reversing the biochemical parameters and histopathological changes. However, this hepatoprotective effect may be weakened, or even be transferred to toxicity with the increase of the administration dose (44 g·kg(-1)·d(-1)) and time (more than 2 months) of this formula. These results were consistent with the histopathological observation and the serum levels.

DISCUSSION AND CONCLUSION

Administration of proper dose and time of DHZCP could well play its hepatoprotective effect and even treat hepatitis, but the safety on liver should be considered when large-dose (44 g·kg(-1)·d(-1)) DHZCP is used for long time (more than 2 months). We suggest that the administration dose and time of DHZCP in clinical use should not be increased and prolonged, and simultaneously liver function should be regularly monitored.

[Study on liver protection, cholagogic effect and hepatotoxicity of Gardeniae fructus]

Gardenia is widely used in clinical treatment to cure acute and chronic liver disease. But in recent two decades, hepatotoxicity has been reported from gardenia and major components. Based on literature research, the liver protection, cholagogic effect and hepatotoxicity have been discussed in-depth, with the purpose to provide a reference for rational usage in clinical and new drug development of gardenia.

Suspended C60 nanoparticles protect against short-term UV and fluoranthene photo-induced toxicity, but cause long-term cellular damage in Daphnia magna

The increased production of nanotechnology materials is a potential source of nano-sized particles (NSPs) in aquatic ecosystems. Meanwhile, polycyclic aromatic hydrocarbons (PAHs), in the presence of ecologically relevant levels of ultraviolet radiation (UV), can be acutely toxic to aquatic species including fish and invertebrates. Considering that suspended carbon-based NSPs (e.g., C60 fullerenes) may act in similar ways as dissolved organic matter (DOM) by altering the bioavailability of PAHs, the objective of this research was to determine the effect of suspended C60 on the photo-induced toxicity of fluoranthene. Transmission electron microscopy indicated that the presence of C60 protected cellular components (e.g., mitochondria, microvilli, and basal infoldings) in organisms exposed to UV and fluoranthene phototoxicity in short-term exposures. However, we found that long-term exposure (21d) of low-level C60 caused significant cellular damage in the Daphnia magna alimentary canal. This paper highlights the importance of examining the interactions between existing stressors and nanoparticles in the aquatic environment.

Gastroprotective and cytotoxic effect of semisynthetic ferruginol derivatives

The gastroprotective abietane diterpene ferruginol has been shown to present high cytotoxicity. In order to obtain active compounds with less cytotoxicity, 18 semisynthetic ferruginol derivatives and totarol were assessed for their gastroprotective effects in the HCl/ethanol-induced gastric lesion model in mice, as well as for cytotoxicity in human gastric epithelial cells (AGS) and human lung fibroblasts (MRC-5). At 20 mg kg−1, the greatest gastroprotective effects were provided by abieta-8,11,13-triene (1), abieta-8,11,13-trien-12-yl-2-chloropropanoate (8), abieta-8,11,13-trien-12-yl propenoate (9), 12-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyloxy)-abieta-8,11,13-triene (17) and 12-(β-D-galactopyranosyloxy)-abieta-8,11,13-triene (18), all of which were as active as the reference drug lansoprazole at 20 mg kg−1, reducing gastric lesions by 69, 76, 67, 72 and 61%, respectively. No relation was observed between lipophilicity and the gastroprotective effect. Compounds that showed the greatest cytotoxicity towards AGS cells were ferruginol (2), the corresponding formate (5), acetate (6), propionate (7), 8, 9, 12-(β-D-glucopyranosyloxy)-abieta-8,11,13-triene (16), 18 and totarol (20) (IC50 18–44 μM). Ferruginol and compounds 5–9, 16, 18 and 20 were the most toxic compounds against fibroblasts (IC50 19–56 μM), with a correlation to AGS cells. The derivative 19 was much more active against AGS cells than towards fibroblasts. The best activity/cytotoxicity ratio was found for compound 17, with a lesion index comparable with lansoprazole at 20 mg kg−1 and cytotoxicity &gt;1000 μM towards MRC-5 and AGS cells, respectively. In conclusion, some derivatives showed a better gastroprotective effect/cytotoxicity ratio than the parent compound ferruginol. A total of 13 new compounds are reported here for the first time.

Protective activity of Jiang-Zhi-Li-Gan against carbon tetrachloride-induced hepatic injury in mice

The administration of carbon tetrachloride (CCl(4)) to mice produced hepatotoxicity, showing a significant increase in the serum levels of alanine transaminase (ALT) and aspartate aminotransferase (AST). Mice pretreated with Jiang-Zhi-Li-Gan (JZLG, 100-900 mg/kg, p.o.), a domestic remedy for liver disease in Rui-Jin Hospital, showed a significant decrease in serum ALT and AST levels when compared to the group treated with CCl(4) alone. The standard drug, bifendate (200 mg/kg, p.o.), also exhibited similar results. In the acute toxicity study, JZLG did not show any mortality up to a dose of 32 g/kg body weight. Based on the results obtained, it can be concluded that JZLG seems to possess hepatoprotective activity in mice. These results support the use of this prescription against chemical hepatic injury.

Preventive role of exogenous testosterone on cisplatin-induced gonadal toxicity: an experimental placebo-controlled prospective trial

OBJECTIVE

To test the preventive role of exogenous T on spermatogenesis after cisplatin chemotherapy.

DESIGN

Placebo-controlled study.

SETTING

The animal laboratory of a medical university.

ANIMAL(S)

Eighty-eight male BALB/c mice were divided into three groups; each group was subdivided into four groups.

INTERVENTION(S)

Subgroups a received two or three cycles of cisplatin (2.5 mg/kg for 5 days + 16 days of recovery), subgroups b received the same chemotherapy regimen with adjuvant high-dose T enanthate (5 mg/100 g body weight) starting 1 week before chemotherapy and repeated every 21 days during chemotherapy, subgroups c received only high-dose T enanthate at the same dosage and intervals; subgroups d received a placebo.

MAIN OUTCOME MEASURE(S)

Testis spermatogenesis function was evaluated after 35 days (short term, group I) or 105 days (long term, groups II and III) of recovery, after the final dose of cisplatin, by histopathology and sperm count.

RESULT(S)

Testis tissue destruction and a significant dose-dependent decrease in spermatogenesis were identified in subgroups a. Both recovered partially during long-term recovery. Exogenous high-dose T caused damage to spermatogenesis, which was reversible (subgroups c). Adjuvant treatment with T had no additive long-term effect in animals treated with low-dose cisplatin (two cycles). However, a significant long-term preventive effect of T was seen in animals receiving high-dose cisplatin (three cycles).

CONCLUSION(S)

Hormonal intervention with exogenous T during chemotherapy had promising effects on spermatogenesis in mice receiving high-dose chemotherapy (regimens frequently used clinically). It had no additive long-term effects in animals receiving low-dose regimens.

Screening of hepatoprotective effect of a herbal mixture against CCl4 induced hepatotoxicity in Swiss albino mice

The hepatoprotective potential of a herbal mixture was evaluated against CCl4 induced liver injury in Swiss albino mice. Liv 52, a commercially available polyherbal hepatoprotective drug was evaluated for comparison. The potential toxicity of the above herbal hepatoprotective agents was also compared. It was observed that there was a reduction in the enzyme biomarkers (Aspartate and Alanine Transaminase) of liver injury in the herbal mixture treated groups, which was similar to the reduction initiated by Liv 52. An increase in glutathione was observed in the herbal mixture treated groups and it was assumed that the herbal mixture protects the liver by virtue of its antioxidant nature along with high regeneration initiation potential. From the study it is also concluded that the herbal mixture is safer than Liv 52.

Hepatoprotective activity of Leucas hirta against CCl4 induced hepatic damage in rats

Methanol and aqueous leaf extracts of L. hirta demonstrated hepatoprotective activity against carbon tetrachloride induced liver damage in rats. The parameters studied were serum total bilirubin, total protein, alanine transaminase, aspartate transaminase and alkaline phosphatase activities. The hepatoprotective activity was also supported by histopathological studies of liver tissue. Results of the biochemical studies of blood samples of CCl4 treated animals showed significant increase in the levels of serum markers and decrease in total protein level reflecting the liver injury caused by CCl4. Whereas blood samples from the animals treated with methanol and aqueous leaf extracts showed significant decrease in the levels of serum markers and increase in total protein indicating the protection of hepatic cells. The results revealed that methanol leaf extract followed by aqueous extract of L. hirta could afford significant protection against CCl4 induced hepatocellular injury.

Hepatoprotective and antibacterial effects of extracts from Trichilia emetica Vahl. (Meliaceae)

Trichilia emetica Vahl. (Meliaceae) is a tree widely distributed in Tropical Africa. It has been used in Mali folk medicine for the treatment of various illnesses. The aim of this work was to study the hepatoprotective and antibacterial effects of a crude aqueous extract from Trichilia emetica root. An ethyl ether fraction from the aqueous extract was also prepared and studied. We have examined the hepatoprotective activity of the extracts on CCl4-induced damage in rat hepatocytes, their toxicity using the brine shrimp bioassay and their antibacterial activity against clinical isolated bacterial strains, which are commonly responsible for respiratory infections. A preliminary phytochemical analysis showed a high polyphenolic content in the aqueous extract and the presence of limonoids in the ethyl ether fraction. These latter compounds may be considered responsible for the good activity against the bacterial strains tested. Trichilia emetica extracts exerted also a significant (P<0.05) hepatoprotective effect at a dose of 1000 microg/ml both on plasma membrane and mitochondrial function as compared to silymarin used as a positive control. These activities may be a result of the presence of either polyphenols or limonoids. Finally, both the aqueous extract and its ethyl ether fraction did not show toxicity (LC50>1000 microg/ml) in the brine shrimp bioassay.

Amifostine for children with medulloblastoma treated with cisplatin-based chemotherapy

In adult patients, amifostine appears to ameliorate cisplatin-related nephrotoxicity and ototoxicity. We assessed the safety and efficacy of amifostine in 11 children with newly diagnosed medulloblastoma/primitive neuroectodermal tumor treated with radiotherapy and vincristine, lomustine, and cisplatin. Amifostine was administered immediately prior to and 4 hr into the cisplatin infusion. Amifostine caused assymptomatic hypotension and hypocalcemia in 18 and 82% of patients, respectively. Despite amifostine use, 78% of patients developed significant ototoxicity. Although relatively well tolerated, amifostine does not appear to have a major impact on ameliorating the risk of developing significant nephro- and ototoxicity in children with medulloblastoma. Larger studies will help clarify these findings.

A randomized trial of amifostine as a cytoprotectant for patients receiving myeloablative therapy for allogeneic hematopoietic stem cell transplantation

We initiated a randomized study of amifostine (the organic thiophosphate formerly known as WR-2721) given to patients during myeloablative conditioning therapy for allogeneic bone marrow transplantation. Amifostine was given at a dose of 1000 mg/day of conditioning and was well tolerated if attention was given to serum calcium levels, blood pressure and antiemetics. Since August 1998, 60 patients (30 on each arm) have completed the study. There was no significant difference in the days to neutrophil or platelet engraftment in either arm of the study. Significantly, the duration of grade I-IV mucositis was decreased in the group that received amifostine (P=0.02). Also grade III or IV infections (P=0.008), duration of antibiotic therapy (P=0.03) and duration of fever (P=0.04) were significantly reduced with amifostine. However, there were no differences in the incidence of grade III or IV mucositis, liver toxicity or renal toxicity. There were also no differences in early mortality, relapse and long-term survival. We conclude that amifostine, while reducing the duration of mucositis and infections (possibly through some preservation of gut mucosal integrity), has a modest effect in allogeneic bone marrow transplants given the multiplicity of factors influencing organ toxicity and survival in this setting.

Water-Soluble Polysaccharide from Eleutherococcus senticosus Stems Attenuates Fulminant Hepatic Failure Induced by D-Galactosamine and Lipopolysaccharide in Mice

The aim of this study was to investigate whether Eleutherococcus senticosus stems could attenuate D-galactosamine/lipopolysaccharide-induced fulminant hepatic failure in mice. E. senticosus, known as Siberian ginseng, is a popular folk medicine used as a tonic in Asia. Preparations of E. senticosus used in this study were as follows; (i) 70% ethanol extract (ii) water extract (iii) ethanol-soluble part of the water extract (iv) polysaccharide obtained as an 80% ethanol insoluble of the water extract. Preparations were given by intraperitoneal (300 mg/kg and 50 mg/kg) or oral (300 mg/kg) injection at 12 hr and 1 hr before a D-galactosamine/lipopolysaccharide injection. The intraperitoneal injection of water extract and polysaccharide significantly lowered serum levels of tumour necrosis factor-alpha, aspartate transaminase and alanine transaminase, improved the histologic changes in liver, inhibited hepatocyte apoptosis confirmed by the terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling method and DNA fragmentation assay, and suppressed the lethality induced by D-galactosamine/lipopolysaccharide. The oral administration of water extract and polysaccharide also reduced serum aspartate transaminase, alanine transaminase and tumour necrosis factor-alpha levels. In contrast 70% ethanol extract and ethanol-soluble part of the water extract had no protective effect when treated intraperitoneally or orally. These results indicate E. senticosus stems attenuate fulminant hepatic failure induced by D-galactosamine/lipopolysaccharide in mice and the protective effect is due to water-soluble polysaccharides in E. senticosus stems.

Bone Marrow Chemoprotection without Compromise of Chemotherapy Efficacy in a Rat Brain Tumor Model

Thiol chemoprotective agents can reduce chemotherapy side effects, but clinical use is limited due to concerns of impaired chemotherapeutic efficacy. We evaluated whether an optimized bone marrow chemoprotection regimen impaired the efficacy of enhanced chemotherapy against rat brain tumors. Nude rats with intracerebral human lung carcinoma xenografts were treated with carboplatin, melphalan, and etoposide phosphate delivered intra-arterially with osmotic blood-brain barrier disruption (n = 8/group). Thiol chemoprotection was N-acetyl-L-cysteine (1000 mg/kg) 60 min before chemotherapy and/or sodium thiosulfate (8 g/m(2)) 4 and 8 h after chemotherapy, when the blood-brain barrier is reestablished. Blood counts were obtained before treatment on day 3 and at sacrifice on day 9. N-acetylcysteine serum clearance half-life was 9 to 11 min. Pretreatment with N-acetylcysteine combined with delayed administration of sodium thiosulfate protected against toxicity toward total white cells, granulocytes, and platelets (P = 0.0016). Enhanced chemotherapy reduced intracerebral tumor volume to 4.3 +/- 1.0 mm(3) compared with 29.1 +/- 4.1 mm(3) in untreated animals (P < 0.0001). Tumor volume was 3.7 +/- 0.6 mm(3) in rats that received N-acetylcysteine before and sodium thiosulfate after chemotherapy. The data indicate the efficacy of enhanced chemotherapy for rat brain tumors was not affected by thiol chemoprotection that provided excellent protection for hematological toxicity. Negative interactions of thiols with antitumor efficacy were avoided by temporal and spatial separation of chemoprotectants and chemotherapy.

New approaches to drug discovery and development: a mechanism-based approach to pharmaceutical research and its application to BNP7787, a novel chemoprotective agent

Any approach applied to drug discovery and development by the medical community and pharmaceutical industry has a direct impact on the future availability of improved, novel, and curative therapies for patients with cancer. By definition, drug discovery is a complex learning process whereby research efforts are directed toward uncovering and assimilating new knowledge to create and develop a drug for the purpose of providing benefit to a defined patient population. Accordingly, a highly desirable technology or approach to drug discovery should facilitate both effective learning and the application of newly discovered observations that can be exploited for therapeutic benefit. However, some believe that drug discovery is largely accomplished by serendipity and therefore appropriately addressed by screening a large number of compounds. Clearly, this approach has not generated an abundance of new drugs for cancer patients and suggests that a tangibly different approach in drug discovery is warranted. We employ an alternative approach to drug discovery, which is based on the elucidation and exploitation of biological, pharmacological, and biochemical mechanisms that have not been previously recognized or fully understood. Mechanism-based drug discovery involves the combined application of physics-based computer simulations and laboratory experimentation. There is increasing evidence that agreement between simulations based on the laws of physics and experimental observations results in a higher probability that such observations are more accurate and better understood as compared with either approach used alone. Physics-based computer simulation applied to drug discovery is now considered by experts in the field to be one of the ultimate methodologies for drug discovery. However, the ability to perform truly comprehensive physics-based molecular simulations remains limited by several factors, including the enormous computer-processing power that is required to perform the formidable mathematical operations and data processing (e.g. memory bandwidth, data storage and retrieval). Another major consideration is the development of software that can generate an appropriate and increasingly complex physical representation of the atomic arrangements of biological systems. During the past 17 years, we have made tremendous progress in addressing some of these obstacles by developing and optimizing physics-based computer programs for the purpose of obtaining increasingly accurate and precise information and by improving the speed of computation. To perform physics-based simulations that involve complex systems of biological and pharmaceutical interest, we have developed methods that enable us to exceed Moore's law. This has been accomplished by parallel processing as well as other methods that have enabled us to study more complex and relevant molecular systems of interest. This paper provides an overview of our approach to drug discovery and describes a novel drug, currently in clinical development, which has directly resulted from the application of this approach.

Genetic engineering of a suboptimal islet graft with A20 preserves beta cell mass and function

Transplantation of an excessive number of islets of Langerhans (two to four pancreata per recipient) into patients with type I diabetes is required to restore euglycemia. Hypoxia, nutrient deprivation, local inflammation, and the beta cell inflammatory response (up-regulation of NF-kappaB-dependent genes such as inos) result in beta cell destruction in the early post-transplantation period. Genetic engineering of islets with anti-inflammatory and antiapoptotic genes may prevent beta cell loss and primary nonfunction. We have shown in vitro that A20 inhibits NF-kappaB activation in islets and protects from cytokine- and death receptor-mediated apoptosis. In vivo, protection of newly transplanted islets would reduce the number of islets required for successful transplantation. Transplantation of 500 B6/AF(1) mouse islets into syngeneic, diabetic recipients resulted in a cure rate of 100% within 5 days. Transplantation of 250 islets resulted in a cure rate of only 20%. Transplantation of 250 islets overexpressing A20 resulted in a cure rate of 75% with a mean time to cure of 5.2 days, comparable to that achieved with 500 islets. A20-expressing islets preserve functional beta cell mass and are protected from cell death. These data demonstrate that A20 is an ideal cytoprotective gene therapy candidate for islet transplantation.

Preclinical evaluation of docusate as protective agent from herpes simplex viruses

Prevention of sexually transmitted infections (STIs) is key to public health efforts to control these diseases. An effective vaginal microbicide could provide topical, broad-spectrum prevention against the transmission of several STI pathogens. Docusate is a sulfated surfactant and, as such, may inactivate viral pathogens by disrupting viral envelopes and/or denaturing/disassociating proteins. Accordingly, the in vitro efficacy and toxicity of docusate (dioctyl sodium sulfosuccinate; Zorex; Meditech Pharmaceuticals, Inc., Scottsdale, Arizona) against herpes simplex viruses (HSV) were evaluated. Docusate was effective in vitro against wild type and drug-resistant strains of HSV type 1 and 2 with EC(90-100) (effective concentration giving 90-100% virus yield reduction) of approximately 0.005% (w/v). Sodium dodecyl sulfate (SDS) was equipotent, however, docusate was somewhat less toxic to uninfected Vero cells compared with SDS after 2 days incubation (docusate CC(50) approximately 0.01% vs. SDS approximately 0.005%). The cytotoxicity profiles of docusate were time- and dose-dependent and thus associated with the frequency of use. Kinetics of inactivation examined by pre-mixing virus and drug in a time-course experiment demonstrated that docusate could reach its EC(90-100) within 30 min. Docusate pretreatment of cells was associated with a 45% reduction in infectivity of those cells, despite a triple washing procedure. Once infected, an approximate 30% plaque reduction was observed with treatment.

Allied studies on the effect of Rosmarinus officinalis L. on experimental hepatotoxicity and mutagenesis

The hepatoprotective and antimutagenic effects of the rosemary essential oil and the ethanolic extract were investigated using carbon tetrachloride and cyclophosphamide as hepatotoxic and mutagenic compounds, respectively. Our results revealed that i.g. administration of the rosemary ethanolic extract (0.15 g/100 g BW) to rats for 3 weeks produced the most pronounced hepatoprotective effect compared to silymarin (reference compound) due to the amelioration of most of the studied serum and liver parameters and confirmed by histopathological examination of the liver tissue. Pretreatment of mice for 7 days with the rosemary essential oil (1.1 mg/g BW) followed by i.p. injection with cyclophosphamide reduced significantly the induced mitodepression in the bone marrow cells of the animals. The potential hepatoprotective and antimutagenic activities of the rosemary ethanolic extract and essential oil, respectively, are attributed to the presence of a relatively high percentage of phenolic compounds with high antioxidant activity (according to our chemical studies).

Saturable metabolism of continuous high-dose ifosfamide with mesna and GM-CSF: a pharmacokinetic study in advanced sarcoma patients. Swiss Group for Clinical Cancer Research (SAKK)

BACKGROUND

The aim of this study was to assess the pharmacology, toxicity and activity of high-dose ifosfamide mesna +/- GM-CSF administered by a five-day continuous infusion at a total ifosfamide dose of 12-18 g/m2 in adult patients with advanced sarcomas.

PATIENTS AND METHODS

Between January 1991 and October 1992 32 patients with advanced or metastatic sarcoma were entered the study. Twenty-seven patients were pretreated including twenty-three with prior ifosfamide at less than 8 g/m2 total dose/cycle. In 25 patients (27 cycles) extensive pharmacokinetic analyses were performed.

RESULTS

The area under the plasma concentration-time curve (AUC) for ifosfamide increased linearly with dose while the AUC's of the metabolites measured in plasma by thin-layer chromatography did not increase with dose, particularly that of the active metabolite isophosphoramide mustard. Furthermore the AUC of the inactive carboxymetabolite did not increase with dose. Interpatient variability of pharmacokinetic parameters was high. Dose-limiting toxicity was myelosuppression at 18 g/m2 total dose with grade 4 neutropenia in five of six patients and grade 4 thrombocytopenia in four of six patients. Therefore the maximum tolerated dose was considered to be 18 g/m2 total dose. There was one CR and eleven PR in twenty-nine evaluable patients (overall response rate 41%).

CONCLUSION

Both the activation and inactivation pathways of ifosfamide are non-linear and saturable at high-doses although the pharmacokinetics of the parent drug itself are dose linear. Ifosfamide doses greater than 14-16 g/m2 per cycle appear to result in a relative decrease of the active metabolite isophosphoramide mustard. These data suggest a dose-dependent saturation or even inhibition of ifosfamide metabolism by increasing high dose ifosfamide and suggest the need for further metabolic studies.