Tannins extracted from immature fruits of Terminalia chebula Fructus Retz. are considered as effective components promoting the process of wound healing. The objective of this study is to explore the optimal extraction and purification technology (OEPT) of tannins, while studying the use of this drug in the treatment of a cutaneous wound of rat as well as its antibacterial effects.
The content of tannin extracts was measured by the casein method, and antibacterial ability was studied by the micro-dilution method in vitro. In wound healing experiment, animals in group Ⅰ, Ⅱ and Ⅲ were treated with vaseline ointment, tannin extracts (tannin content: 81%) and erythromycin ointment, respectively (5 mg of ointment were applied on each wound). To evaluate the process of wound healing, selected pharmacological and biochemical parameters were applied.
After optimal extraction and purification, content of tannin extracts was increased to 81%. Tannin extracts showed the inhibition of Staphylococcus aureus and Klebsiella Pneumonia in vitro. After excision of wounds, on days 7 and 10, the percent of wound contraction of group Ⅱ was higher than that of group Ⅰ. After being hurt with wounds, on days 3, 7, and 10, the wound healing quality of group Ⅱ was found to be better than that of group Ⅰ in terms of granulation formation and collagen organization. After wound creation, on day 3, the vascular endothelial growth factor expression of group Ⅱ was higher than that of group Ⅰ.
The results suggest that tannin extracts from dried immature fruits of Terminalia chebula Fructus Retz. can promote cutaneous wound healing in rats, probably resulting from a powerful anti-bacterial and angiogenic activity of the extracts.
Terminalia chebula Retz is traditionally used to relieve constipation. The current study was performed to investigate the pharmacological action of aqueous extract of Terminalia chebula seeds (ATC) in vitro and in vivo.
Terminal pieces of rat ileum were suspended in organ bath containing Tyrode solution. The ileum spontaneous motility frequency and contractility were recorded isotonically. To induce ileal contraction, carbachol and ATC were added to the organ bath. In addition, the effect of hexamethonium, indomethacin, atropine, and verapamil on the ATC-induced ileal contractions was also investigated. The effectiveness of ATC on relieving morphine-induced constipation was investigated in an in vivo study by measuring the faecal number, faecal water content, and intestinal transit ratio.
ATC increased the frequency of ileum motility and tension of contraction dose-dependently (P < 0.05). Responses induced by ATC were inhibited by pre-treatment of the tissue with verapamil. The ATC activities were not affected by atropine, hexamethonium, and indomethacin. The faecal number and faecal water content were increased dose-dependently by ATC (P < 0.05).
The excitatory effects of ATC on ileal contractile frequency and tension are possibly mediated through Ca2+ channels activation. The results of the present study support the traditional usage of ATC for the treatment of constipation.
calcium channels; gut; intestinal motility; morphine; plant extracts; rat; seed; Terminalia
Cellular damage caused by reactive oxygen species (ROS) has been implicated in several diseases, and hence natural antioxidants have significant importance in human health. The present study was carried out to evaluate the in vitro antioxidant and reactive oxygen species scavenging activities of Terminalia chebula, Terminalia belerica and Emblica officinalis fruit extracts.
The 70% methanol extracts were studied for in vitro total antioxidant activity along with phenolic and flavonoid contents and reducing power. Scavenging ability of the extracts for radicals like DPPH, hydroxyl, superoxide, nitric oxide, hydrogen peroxide, peroxynitrite, singlet oxygen, hypochlorous acid were also performed to determine the potential of the extracts.
The ability of the extracts of the fruits in exhibiting their antioxative properties follow the order T. chebula >E. officinalis >T. belerica. The same order is followed in their flavonoid content, whereas in case of phenolic content it becomes E. officinalis >T. belerica >T. chebula. In the studies of free radicals' scavenging, where the activities of the plant extracts were inversely proportional to their IC50 values, T. chebula and E. officinalis were found to be taking leading role with the orders of T. chebula >E. officinalis >T. belerica for superoxide and nitric oxide, and E. officinalis >T. belerica >T. chebula for DPPH and peroxynitrite radicals. Miscellaneous results were observed in the scavenging of other radicals by the plant extracts, viz., T. chebula >T. belerica >E. officinalis for hydroxyl, T. belerica >T. chebula >E. officinalis for singlet oxygen and T. belerica >E. officinalis >T. chebula for hypochlorous acid. In a whole, the studied fruit extracts showed quite good efficacy in their antioxidant and radical scavenging abilities, compared to the standards.
The evidences as can be concluded from the study of the 70% methanol extract of the fruits of Terminalia chebula, Terminalia belerica and Emblica officinalis, imposes the fact that they might be useful as potent sources of natural antioxidant.
The aqueous extract of Jwarhar mahakashay Ayurvedic preparation (from the roots of Hemidesmus indicus R. Br., Rubia cordifolia L., Cissampelos pareira L.; fruits of Terminalia chebula Retz., Emblica officinalis Gaertn., Terminalia bellirica Roxb., Vitis vinifera L., Grewia asiatica L., Salvadora persica L. and granules of Saccharum officinarum L.) has been used as a traditional antipyretic. Experimental studies confirmed its antipyretic–analgesic effect with very low ulcerogenicity and toxicity. Flavonoids, glycosides and tannins were later found to be present in the extract. Detailed chemical investigations were undertaken after hydrolysis of extract using spectroscopic and chromatography methods to determine its active chemical constituent. UV-Visible spectroscopy showed absorbance maxima at 220 and 276 nm, while fourier transform infra-red investigations indicated an end carboxylic O–H structure at 2940 cm−1 suggesting the presence of glycoside-linked flavonoids. Thin layer chromatography and high performance liquid chromatography also confirmed the possibility of at least one major and two minor compounds in this abstract. Detailed examination using gas chromatography-mass spectrometry led to the identification of the principal component as 2-(1-oxopropyl)-benzoic acid, which is quite similar to the active compound found in the standard drug Aspirin (2-acetyl-oxybenzoic acid).
Antipyretic; chromatography; spectroscopy; polyherbal preparation; Jwarahar mahakashay
In the present study, we firstly compared rat intestinal α-glucosidase inhibitory activity by different ethanol-aqueous extractions from the dried fruits of Terminalia chebula Retz. The enzymatic assay showed that the 80% ethanol extract was more potent against maltase activity than both 50% and 100% ethanol extracts. By HPLC analysis, it was determined that the 80% ethanol extract had a higher content of chebulagic acid than each of 50% or 100% ethanol extract. Next, we investigated how efficiently chebulagic acid could inhibit sugar digestion by determining the glucose level on the apical side of the Caco-2 cell monolayer. The result showed that the maltose-hydrolysis activity was down-regulated by chebulagic acid, which proved to be a reversible inhibitor of maltase in Caco-2 cells. On the other hand, chebulagic acid showed a weak inhibition of sucrose-hydrolysis activity. Meanwhile, chebulagic acid did not have an obvious influence on intestinal glucose uptake and was not effective on glucose transporters. Further animal studies revealed that the oral administration of chebulagic acid (100 mg/kg body weight) significantly reduced postprandial blood glucose levels by 11.1% in maltose-loaded Sprague-Dawley (SD) rats compared with the control group, whereas the oral administration of chebulagic acid did not show a suppressive effect on postprandial hyperglycemia in sucrose- or glucose-loaded SD-rats. The results presented here suggest that chebulagic acid from T. chebula can be used to control blood glucose and manage type 2 diabetes, although clinical trials are needed.
Terminalia chebula; chebulagic acid; α-glucosidase inhibitor; anti-hyperglycemia
To evaluate the antioxidant and free-radical scavenging activities of triethylchebulate (TCL), an aglycone isolated from the fruit of Terminalia chebula Retz.
Materials and Methods:
Microsomes, mitochondria and red blood cells (RBCs) were isolated from rat liver. The antioxidant capacities were evaluated by determining the inhibitory effects of TCL on lipid peroxidation, hydrogen peroxide (H2O2)-induced RBCs hemolysis and RBCs autoxidative hemolysis. The free-radical scavenging activities were evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) method and 2´,7´-dichlorodihydrofluorescin diacetate (DCFH2-DA) assay.
TCL significantly inhibited FeSO4/Cys-induced microsomes lipid peroxidation and protected both H2O2--induced RBCs hemolysis and RBCs auto-hemolysis in a dose-dependent manner. Furthermore, TCL demonstrated potent DPPH free-radical scavenging ability with IC50 at 2.4×10-5 M. In addition, TCL also moderately suppressed azide-induced mitochondria ROS formation.
These results demonstrated that TCL was a strong antioxidant and free-radical scavenger, which might contribute to the anti-oxidative ability of Terminalia chebula Retz.
Anti-oxidant; hemolysis; lipid peroxidation; reactive oxygen species; Terminalia chebula Retz; triethylchebulate
Iron chelation therapy (ICT) has been applied for the patients with iron overload-associated liver dysfunction since it is one of the causes of death in patients with intractable hematological diseases requiring multiple red blood cell transfusions. Recently, deferasirox (DSX), a novel, once-daily oral iron chelator, was demonstrated to have similar efficacy to the conventional continuous infusion of deferoxamine on a decrease in serum ferritin (SF) level in heavily transfused patients. We show three cases of transfusion-mediated iron-overloaded patients with an elevated serum alanine aminotransaminase (ALT). All three patients who received the ICT with DSX showed a decrease in ALT level in association with a decrease in SF level. It is suggested that DSX therapy could be considered to expect the improvement of liver damage for iron-overloaded patients with an abnormal ALT level.
Emerging clinical data indicate that transfusion-dependent patients with bone marrow-failure syndromes (BMFS) are at risk of the consequences of iron overload, including progressive damage to hepatic, endocrine, and cardiac organs. Despite the availability of deferoxamine (DFO) in Korea since 1998, data from patients with myelodysplastic syndromes, aplastic anemia, and other BMFS show significant iron overload and damage to the heart and liver. The recent introduction of deferasirox, a once-daily, oral iron chelator, may improve the availability of iron chelation therapy to iron-overloaded patients, and improve compliance in patients who may otherwise find adherence to the DFO regimen difficult.
Aplastic anemia; Myelodysplastic syndromes; Iron overload; Deferasirox
The effect of deferasirox dosing tailored for iron burden and iron loading based on liver iron concentration (LIC) was assessed over 1 year in less versus more heavily iron-overloaded patients in a substudy of the Evaluation of Patients’ Iron Chelation with Exjade®. Deferasirox starting dose was 10–30 mg/kg/day, depending on blood transfusion frequency, with recommended dose adjustments every 3 months. Therapeutic goals were LIC maintenance or reduction in patients with baseline LIC <7 or ≥7 mg Fe/g dry weight (dw), respectively. Changes in LIC (R2-magnetic resonance imaging) and serum ferritin after 1 year were assessed. Adverse events (AEs) and laboratory parameters were monitored throughout. Of 374 patients, 71 and 303 had baseline LIC <7 and ≥7 mg Fe/g dw, respectively; mean deferasirox doses were 20.7 and 27.1 mg/kg/day (overall average time to dose increase, 24 weeks). At 1 year, mean LIC and median serum ferritin levels were maintained in the low-iron cohort (−0.02 ± 2.4 mg Fe/g dw, −57 ng/mL; P = not significant) and significantly decreased in the high-iron cohort (−6.1 ± 9.1 mg Fe/g dw, −830 ng/mL; P < 0.0001). Drug-related gastrointestinal AEs, mostly mild to moderate, were more frequently reported in the <7 versus ≥7 mg Fe/g dw cohort (39.4 versus 20.8 %; P = 0.001) and were not confounded by diagnosis, dosing, ethnicity, or hepatitis B and/or C history. Reported serum creatinine increases did not increase in low- versus high-iron cohort patients. Deferasirox doses of 20 mg/kg/day maintained LIC <7 mg Fe/g dw and doses of 30 mg/kg/day were required for net iron reduction in the high-iron cohort, with clinically manageable safety profiles. The higher incidence of gastrointestinal AEs at lower iron burdens requires further investigation.
Iron overload; Iron chelation therapy; Deferasirox; Liver iron concentration
The Escherichia coli Fur protein, with its iron(II) cofactor, represses iron assimilation and manganese superoxide dismutase (MnSOD) genes, thus coupling iron metabolism to protection against oxygen toxicity. Iron assimilation is triggered by iron starvation in wild-type cells and is constitutive in fur mutants. We show that iron metabolism deregulation in fur mutants produces an iron overload, leading to oxidative stress and DNA damage including lethal and mutagenic lesions. fur recA mutants were not viable under aerobic conditions and died after a shift from anaerobiosis to aerobiosis. Reduction of the intracellular iron concentration by an iron chelator (ferrozine), by inhibition of ferric iron transport (tonB mutants), or by overexpression of the iron storage ferritin H-like (FTN) protein eliminated oxygen sensitivity. Hydroxyl radical scavengers dimethyl sulfoxide and thiourea also provided protection. Functional recombinational repair was necessary for protection, but SOS induction was not involved. Oxygen-dependent spontaneous mutagenesis was significantly increased in fur mutants. Similarly, SOD deficiency rendered sodA sodB recA mutants nonviable under aerobic conditions. Lethality was suppressed by tonB mutations but not by iron chelation or overexpression of FTN. Thus, superoxide-mediated iron reduction was responsible for oxygen sensitivity. Furthermore, overexpression of SOD partially protected fur recA mutants. We propose that a transient iron overload, which could potentially generate oxidative stress, occurs in wild-type cells on return to normal growth conditions following iron starvation, with the coupling between iron and MnSOD regulation helping the cells cope.
In general, in women with transfusion-dependent thalassemia, during pregnancy, iron chelation therapy is ceased. We report a splenectomized patient, who was an excellent complier with chelation therapy, who before embarking on a pregnancy showed no evidence of iron overload, with normal cardiac, thyroid function and glucose metabolism. Laboratory findings showed ferritin 67 μg/L, myocardial T2* of 34 ms and liver magnetic resonance imaging (MRI) liver iron concentration of 1 mg/g dry weight. She became pregnant by in vitro fertilization in October 2006, delivery occurred in June 2007. She breast fed for 2 months. After 12 months without iron chelation, ferritin was 1583 μg/L. Quantitative MRI showed myocardial T2* of 27 ms, that the liver iron concentration had increased to 11.3 mg/g dry weight, indicative of moderate to heavy iron load. This case demonstrates that iron overload can develop rapidly and that physicians caring for patients with transfusion-dependent thalassemia should be particularly alert to any discontinuation of chelation therapy over time.
thalassemia major; pregnancy; transfusion iron load; chelation therapy
Synovial iron deposition associated with rheumatoid disease may result in the production of highly reactive oxygen free radicals, leading to tissue damage. This chain of events can be interrupted by iron chelation. Families of strong iron (III) chelators have been tested for their iron scavenging properties in vitro and their effects assessed in vivo using a rat model of inflammation. All the chelators competed successfully for iron with apotransferrin, and some removed up to 34% of iron from ferritin. The best anti-inflammatory effects were achieved with the most hydrophilic chelators and those which chelated iron most avidly. Activity was dependent on dose. The route of administration was also an important factor with lower affinity chelators. This work introduces a range of simple bidentate iron chelators, which under certain conditions exceed desferrioxamine in their iron scavenging abilities, and some of which, in this simple animal model, approach indomethacin in their anti-inflammatory capabilities.
Many patients with transfusional iron overload are at risk for progressive organ dysfunction and early death and poor compliance with older chelation therapies is believed to be a major contributing factor. Phase II/III studies have shown that oral deferasirox 20–30 mg/kg/d reduces iron burden, depending on transfusional iron intake.
The prospective, open-label, 1-yr ESCALATOR study in the Middle East was designed to evaluate once-daily deferasirox in patients ≥2 yr with β-thalassaemia major and iron overload who were previously chelated with deferoxamine and/or deferiprone. Most patients began treatment with deferasirox 20 mg/kg/d; doses were adjusted in response to markers of over- or under-chelation. The primary endpoint was treatment success, defined as a reduction in liver iron concentration (LIC) of ≥3 mg Fe/g dry weight (dw) if baseline LIC was ≥10 mg Fe/g dw, or final LIC of 1–7 mg Fe/g dw for patients with baseline LIC of 2 to <10 mg Fe/g dw.
Overall, 233/237 enrolled patients completed 1 yr’s treatment. Mean baseline LIC was 18.0 ± 9.1 mg Fe/g dw, while median serum ferritin was 3356 ng/mL. After 1 yr’s deferasirox treatment, the intent-to-treat population experienced a significant treatment success rate of 57.0% (P = 0.016) and a mean reduction in LIC of 3.4 mg Fe/g dw. Changes in serum ferritin appeared to parallel dose increases at around 24 wk. Most patients (78.1%) underwent dose increases above 20 mg/kg/d, primarily to 30 mg/kg/d. Drug-related adverse events were mostly mild to moderate and resolved without discontinuing treatment.
The results of the ESCALATOR study in primarily heavily iron-overloaded patients confirm previous observations in patients with β-thalassaemia, highlighting the importance of timely deferasirox dose adjustments based on serum ferritin levels and transfusional iron intake to ensure patients achieve their therapeutic goal of maintenance or reduction in iron burden.
iron chelation; deferasirox; β-thalassaemia; transfusional iron overload
Available iron chelation regimes in thalassaemia may achieve different changes in cardiac and hepatic iron as assessed by MR. The aim of this study was to assess the efficacy of four available iron chelator regimes in 232 thalassaemia major patients by assessing the rate of change in repeated measurements of cardiac and hepatic MR.
For the heart, deferiprone and the combination of deferiprone and deferoxamine significantly reduced cardiac iron at all levels of iron loading. As patients were on deferasirox for a shorter time, a second analysis ("Initial interval analysis") assessing the change between the first two recorded MR results for both cardiac and hepatic iron (minimum interval 12 months) was made. Combination therapy achieved the most rapid fall in cardiac iron load at all levels and deferiprone alone was significantly effective with moderate and mild iron load. In the liver, deferasirox effected significant falls in iron load and combination therapy resulted in the most rapid decline.
With the knowledge of the efficacy of the different available regimes and the specific iron load in the heart and the liver, appropriate tailoring of chelation therapy should allow clearance of iron. Combination therapy is best in reducing both cardiac and hepatic iron, while monotherapy with deferiprone or deferasirox are effective in the heart and liver respectively. The outcomes of this study may be useful to physicians as to the chelation they should prescribe according to the levels of iron load found in the heart and liver by MR.
Increased bone marrow iron levels in patients with haematological malignancies is an independent risk factor for developing invasive pulmonary aspergillosis (IPA), suggesting an important role for iron uptake in the pathogenesis of IPA. We sought to determine the potential for combination therapy with the iron chelator deferasirox + liposomal amphotericin B (LAmB) to improve the outcome of murine IPA compared with LAmB monotherapy.
In vitro MIC and minimum fungicidal concentration (MFC) values of the iron chelator, deferasirox, for Aspergillus fumigatus were determined by microdilution assay. In addition, we studied the efficacy of deferasirox alone or combined with LAmB in treating immunocompromised mice infected with A. fumigatus via inhalation.
Deferasirox was cidal in vitro against A. fumigatus, with an MIC and MFC of 25 and 50 mg/L, respectively. Deferasirox monotherapy modestly prolonged survival of mice with IPA. Combination deferasirox + LAmB therapy synergistically improved survival and reduced lung fungal burden compared with either monotherapy alone.
Iron chelation therapy with deferasirox alone or in combination with LAmB is effective in treating experimental IPA. Further study of deferasirox is warranted as adjunctive therapy for IPA infections.
Aspergillus fumigatus; LAmB; IPA
With transfusional iron overload, almost all the excess iron is sequestered intracellularly as rapidly mobilizable, dispersed, soluble, ferritin iron, and as aggregated, insoluble hemosiderin iron for long-term storage. Established magnetic resonance imaging (MRI) indicators of tissue iron (R2, R2*) are principally influenced by hemosiderin iron and change slowly, even with intensive iron chelation. Intracellular ferritin iron is evidently in equilibrium with the low-molecular-weight cytosolic iron pool that can change rapidly with iron chelation. We have developed a new magnetic resonance imaging (MRI) method to separately measure ferritin and hemosiderin iron, based on the non-monoexponential signal decay induced by aggregated iron in multiple-spin-echo sequences. We have initially validated the method in agarose phantoms and in human liver explants and shown the feasibility of its application in patients with thalassemia major. Measurement of tissue ferritin iron is a promising new means to rapidly evaluate the effectiveness of iron-chelating regimens.
iron; ferritin; hemosiderin; thalassemia; magnetic susceptibility; magnetic resonance
Burgeoning antibiotic resistance in Pseudomonas aeruginosa has necessitated the development of anti pathogenic agents that can quench acylhomoserine lactone (AHL) mediated QS with least risk of resistance. This study explores the anti quorum sensing potential of T. chebula Retz. and identification of probable compounds(s) showing anti QS activity and the mechanism of attenuation of P. aeruginosa PAO1 virulence factors.
Methods and Results
Methanol extract of T. chebula Retz. fruit showed anti QS activity using Agrobacterium tumefaciens A136. Bioactive fraction (F7), obtained by fractionation of methanol extract using Sephadex LH20, showed significant reduction (p<0.001) in QS regulated production of extracellular virulence factors in P. aeruginosa PAO1. Biofilm formation and alginate were significantly (p<0.05) reduced with enhanced (20%) susceptibility to tobramycin. Real Time PCR of F7 treated P. aeruginosa showed down regulation of autoinducer synthase (lasI and rhlI) and their cognate receptor (lasR and rhlR) genes by 89, 90, 90 and 93%, respectively. Electrospray Ionization Mass Spectrometry also showed 90 and 64% reduction in the production of 3-oxo-C12HSL and C4HSL after treatment. Decrease in AHLs as one of the mechanisms of quorum quenching by F7 was supported by the reversal of inhibited swarming motility in F7-treated P. aeruginosa PAO1 on addition of C4HSL. F7 also showed antagonistic activity against 3-oxo-C12HSL-dependent QS in E. coli bioreporter. C. elegans fed on F7-treated P. aeruginosa showed enhanced survival with LT50 increasing from 24 to 72 h. LC-ESI-MS of F7 revealed the presence of ellagic acid derivatives responsible for anti QS activity in T. chebula extract.
This is the first report on anti QS activity of T. chebula fruit linked to EADs which down regulate the expression of lasIR and rhlIR genes with concomitant decrease in AHLs in P. aeruginosa PAO1 causing attenuation of its virulence factors and enhanced sensitivity of its biofilm towards tobramycin.
We describe a novel missense mutation of ceruloplasmin in a patient with aceruloplasminaemia causing the replacement of a neutral amino acid (phenylalanine) with a polar one (serine) at position 198, probably leading to abnormal folding and secretion of the protein. The patient showed mild microcytic anaemia, mild hepatic iron overload, and marked brain iron overload. Six months of therapy with deferiprone was ineffective in removing iron from the tissues. Deferoxamine was more efficient in removing excess iron from the liver but aggravated the disease related anaemia. After more than one year of chelation treatment, the brain magnetic resonance imaging signal did not change. Overall, these findings indicate that treatment of iron overload in aceruloplasminaemia is a difficult challenge and that new iron chelators, more efficient in crossing the blood-brain barrier, are needed.
ceruloplasmin; iron overload; brain MRI; SQUID
Children with severe chronic hemolytic anemia or congenital erythroblastopenia are transfusion dependent. Long-term transfusion therapy prolongs life but results in a toxic accumulation of iron in the organs. The human body cannot actively eliminate excess iron. Therefore, the use of a chelating agent is required to promote excretion of iron. So far, iron chelation has been done by subcutaneous infusion of deferoxamine given over 10 h, 5–6 days per week. Compliance is poor and chelation often insufficient. Ferritin measurements and sometimes liver biopsies are used to evaluate the iron burden in the body. At the present time, new iron chelators that can be given orally are available. Furthermore, magnetic resonance imaging (MRI) assessment of tissue iron is a noninvasive and highly reproducible method, which is able to quantitate organ iron burden. In conclusion, iron overload can be measured more accurately with noninvasive methods such as MRI. Deferasirox is a once-daily oral therapy for treating transfusional iron overload, which improves patient compliance and quality of life.
Iron overload; Diagnosis; Chelators
Iron chelators for the treatment of malaria have proven therapeutic activity in vitro and in vivo in both humans and mice, but their clinical use is limited by the unsuitable absorption and pharmacokinetic properties of the few available iron chelators. FBS0701, (S)3”-(HO)-desazadesferrithiocin-polyether [DADFT-PE], is an oral iron chelator currently in Phase 2 human studies for the treatment of transfusional iron overload. The drug has very favorable absorption and pharmacokinetic properties allowing for once-daily use to deplete circulating free iron with human plasma concentrations in the high µM range. Here we show that FBS0701 has inhibition concentration 50% (IC50) of 6 µM for Plasmodium falciparum in contrast to the IC50 for deferiprone and deferoxamine at 15 and 30 µM respectively. In combination, FBS0701 interfered with artemisinin parasite inhibition and was additive with chloroquine or quinine parasite inhibition. FBS0701 killed early stage P. falciparum gametocytes. In the P. berghei Thompson suppression test, a single dose of 100 mg/kg reduced day three parasitemia and prolonged survival, but did not cure mice. Treatment with a single oral dose of 100 mg/kg one day after infection with 10 million lethal P. yoelii 17XL cured all the mice. Pretreatment of mice with a single oral dose of FBS0701 seven days or one day before resulted in the cure of some mice. Plasma exposures and other pharmacokinetics parameters in mice of the 100 mg/kg dose are similar to a 3 mg/kg dose in humans. In conclusion, FBS0701 demonstrates a single oral dose cure of the lethal P. yoelii model. Significantly, this effect persists after the chelator has cleared from plasma. FBS0701 was demonstrated to remove labile iron from erythrocytes as well as enter erythrocytes to chelate iron. FBS0701 may find clinically utility as monotherapy, a malarial prophylactic or, more likely, in combination with other antimalarials.
Regular red cell transfusion therapy ameliorates disease-related morbidity and can be lifesaving in patients with various hematological disorders. Transfusion therapy, however, causes progressive iron loading, which, if untreated, results in endocrinopathies, cardiac arrhythmias and congestive heart failure, hepatic fibrosis, and premature death. Iron chelation therapy is used to prevent iron loading, remove excess accumulated iron, detoxify iron, and reverse some of the iron-related complications. Three chelators have undergone extensive testing to date: deferoxamine, deferasirox, and deferiprone (although the latter drug is not currently licensed for use in North America where it is available only through compassionate use programs and research protocols). These chelators differ in their modes of administration, pharmacokinetics, efficacy with regard to organ-specific iron removal, and adverse-effect profiles. These differential properties influence acceptability, tolerability and adherence to therapy, and, ultimately, the effectiveness of treatment. Chelation therapy, therefore, must be individualized, taking into account patient preferences, toxicities, ongoing transfusional iron intake, and the degree of cardiac and hepatic iron loading.
transfusion; iron; chelation; magnetic resonance imaging
A controlled trial of continuous chelation therapy in regularly transfused children with homozygous β-thalassaemia has been in progress at the Hospital for Sick Children since April 1966. In the sixth and seventh years of the trial the effect of this treatment on iron overload has been assessed by estimating serum ferritin levels and liver iron concentrations in both chelator-treated and control groups. When compared with non-chelated controls, results of both these estimations were invariably lower in the chelated group. However, all the results in both groups were very high, and fell within the ranges observed in untreated idiopathic haemochromatosis. A close correlation was found between serum ferritin levels and liver iron concentrations in these children, indicating that serum ferritin is a valuable alternative to liver iron concentration in the assessment of visceral iron overload, even when massive tissue siderosis is present.
Mucormycosis causes mortality in at least 50% of cases despite current first-line therapies. Clinical and animal data indicate that the presence of elevated available serum iron predisposes the host to mucormycosis. Here we demonstrate that deferasirox, an iron chelator recently approved for use in humans by the US FDA, is a highly effective treatment for mucormycosis. Deferasirox effectively chelated iron from Rhizopus oryzae and demonstrated cidal activity in vitro against 28 of 29 clinical isolates of Mucorales at concentrations well below clinically achievable serum levels. When administered to diabetic ketoacidotic or neutropenic mice with mucormycosis, deferasirox significantly improved survival and decreased tissue fungal burden, with an efficacy similar to that of liposomal amphotericin B. Deferasirox treatment also enhanced the host inflammatory response to mucormycosis. Most importantly, deferasirox synergistically improved survival and reduced tissue fungal burden when combined with liposomal amphotericin B. These data support clinical investigation of adjunctive deferasirox therapy to improve the poor outcomes of mucormycosis with current therapy. As iron availability is integral to the pathogenesis of other infections (e.g., tuberculosis, malaria), broader investigation of deferasirox as an antiinfective treatment is warranted.
Herpes simplex virus 1 (HSV-1) is a common human pathogen that causes lifelong latent infection of sensory neurons. Non-nucleoside inhibitors that can limit HSV-1 recurrence are particularly useful in treating immunocompromised individuals or cases of emerging acyclovir-resistant strains of herpesvirus. We report that chebulagic acid (CHLA) and punicalagin (PUG), two hydrolyzable tannins isolated from the dried fruits of Terminalia chebula Retz. (Combretaceae), inhibit HSV-1 entry at noncytotoxic doses in A549 human lung cells. Experiments revealed that both tannins targeted and inactivated HSV-1 viral particles and could prevent binding, penetration, and cell-to-cell spread, as well as secondary infection. The antiviral effect from either of the tannins was not associated with induction of type I interferon-mediated responses, nor was pretreatment of the host cell protective against HSV-1. Their inhibitory activities targeted HSV-1 glycoproteins since both natural compounds were able to block polykaryocyte formation mediated by expression of recombinant viral glycoproteins involved in attachment and membrane fusion. Our results indicated that CHLA and PUG blocked interactions between cell surface glycosaminoglycans and HSV-1 glycoproteins. Furthermore, the antiviral activities from the two tannins were significantly diminished in mutant cell lines unable to produce heparan sulfate and chondroitin sulfate and could be rescued upon reconstitution of heparan sulfate biosynthesis. We suggest that the hydrolyzable tannins CHLA and PUG may be useful as competitors for glycosaminoglycans in the management of HSV-1 infections and that they may help reduce the risk for development of viral drug resistance during therapy with nucleoside analogues.
Although iron overload is clinically significant, only limited data have been published on iron overload in haematological diseases. We investigated cardiac and liver iron accumulation by magnetic resonance imaging (MRI) in a cohort of 87 subjects who did not receive chelation, including 59 haematological patients. M-HIC (MRI-based hepatic iron concentration, normal values <36 μmol/g) is a non-invasive, liver biopsy-calibrated method to analyse iron concentration. This method, calibrated to R2 (transverse relaxation rate), was used as a reference standard (M-HIC(R2)). Transfusions and ferritin were evaluated. Mean M-HIC(R2) and cardiac R* of all patients were 142 μmol/g (95% CI, 114–170) and 36.4 1/s (95% CI, 34.2–38.5), respectively. M-HIC(R2) was higher in haematological patients than in patients with chronic liver disease or normal controls (P<0.001). Clearly elevated cardiac R2* was found in two myelodysplastic syndrome (MDS) patients with severe liver iron overload. A poor correlation was found between liver and cardiac iron (n=82, r=0.322, P=0.003), in contrast to a stronger correlation in MDS (n=7, r=0.905, P=0.005). In addition to transfusions, MDS seemed to be an independent factor in iron accumulation. In conclusion, the risk for cardiac iron overload in haematological diseases other than MDS is very low, despite the frequently found liver iron overload.
cardiac; liver; iron overload; magnetic resonance imaging