Versatile anti-infective properties of pyrido- and dihydropyrido[2,3-d]pyrimidine-based compounds.

A series of 1H-indeno[2',1':5,6]dihydropyrido[2,3-d]pyrimidine and 1H-indeno[2',1':5,6]pyrido[2,3-d]pyrimidine derivatives was prepared and screened for antiparasitic and viral RNase H inhibitory activity. Several compounds showed considerable activity against Toxoplasma gondii parasites and Leishmania major amastigotes, which warrants further investigation. Based on the structural similarities of certain derivatives with common viral RNase H inhibitors, a HIV-1 RNase H assay was used to study the RNase H inhibition by selected test compounds. Docking of active derivatives into the active site of the HIV-1 RNase H enzyme was carried out. The new compound 2a, inactive in the antiparasitic tests, showed distinct HIV-1 RNase H inhibition. Thus, ring substitution determines antiparasitic or HIV-1 RNase H inhibitory activity of this promising compound class.

Regiospecific Reduction of 4,6-Dinitrobenzimidazoles: Synthesis, Characterization, and Biological Evaluation.

The regiospecific reduction of 4,6-dinitrobenzimidazole derivatives leading to the corresponding 4-amino-6-nitrobenzimidazoles was studied. The identification of the formed product structures was accomplished by spectroscopic and X-ray diffraction data. The anticancer and antiparasitic activities of the synthesized compounds were examined, and promising activities against Toxoplasma gondii and Leishmania major parasites were discovered for certain 4,6-dinitrobenzimidazoles in addition to moderate anticancer activities of the 4-amino-6-nitrobenzimidazole derivatives against T. gondii cells. However, the tumor cell experiments revealed a promising sensitivity of p53-negative colon cancer cells to these compounds.

Evaluation of Ruthenium(II) N-Heterocyclic Carbene Complexes as Enzymatic Inhibitory Agents with Antioxidant, Antimicrobial, Antiparasitical and Antiproliferative Activity.

A series of [RuCl2(p-cymene)(NHC)] complexes were obtained by reacting [RuCl2(p-cymene)]2 with in situ generated Ag-N-heterocyclic carbene (NHC) complexes. The structure of the obtained complexes was determined by the appropriate spectroscopy and elemental analysis. In addition, we evaluated the biological activities of these compounds as antienzymatic, antioxidant, antibacterial, anticancer, and antiparasitic agents. The results revealed that complexes 3b and 3d were the most potent inhibitors against AchE with IC50 values of 2.52 and 5.06 µM mL-1. Additionally, 3d proved very good antimicrobial activity against all examined microorganisms with IZ (inhibition zone) over 25 mm and MIC (minimum inhibitory concentration) < 4 µM. Additionally, the ligand 2a and its corresponding ruthenium (II) complex 3a had good cytotoxic activity against both cancer cells HCT-116 and HepG-2, with IC50 values of (7.76 and 11.76) and (4.12 and 9.21) µM mL-1, respectively. Evaluation of the antiparasitic activity of these complexes against Leishmania major promastigotes and Toxoplasma gondii showed that ruthenium complexes were more potent than the free ligand, with an IC50 values less than 1.5 µM mL-1. However, 3d was found the best one with SI (selectivity index) values greater than 5 so it seems to be the best candidate for antileishmanial drug discovery program, and much future research are recommended for mode of action and in vivo evaluation. In general, Ru-NHC complexes are the most effective against L. major promastigotes.

An Update on Natural Antileishmanial Treatment Options from Plants, Fungi and Algae.

Efficient drugs for the treatment of leishmaniasis, which is classified as a neglected tropical disease, are sought for. This review covers potential drug candidates from natural plant, fungus and algae sources, which were described over the last six years. The identification of these natural antileishmanials often based on the knowledge of traditional medicines. Crucial insights into the activities of these natural remedies against Leishmania parasites and against infections caused by these parasites in laboratory animals or patients are provided and compared with selected former active examples published more than six years ago. In addition, immuno-modulatory natural antileishmanials and recent developments on combination therapies including natural products and approved antileishmanials are discussed. The described natural products revealed promising data warranting further efforts on the discovery and development of new antileishmanials based on patterns from nature.

p-Trifluoromethyl- and p-pentafluorothio-substituted curcuminoids of the 2,6-di[(E)-benzylidene)]cycloalkanone type: Syntheses and activities against Leishmania major and Toxoplasma gondii parasites.

A series of the title curcuminoids with structural variance in the heteroatom of the cycloalkanone and the p-substituents of the phenyl rings were tested for their activities against Leishmania major and Toxoplasma gondii parasites. The majority of them showed high activities against both parasite forms with EC50 values in the sub-micromolar concentration range. Bis(p-pentafluorothio)-substituted 3,5-di[(E)-benzylidene]piperidin-4-one 1b was not just noticeable antiparasitic, but also exhibited a considerable selectivity for L. major promastigotes over normal Vero cells. While derivatives differing only in the p-phenyl substituents being CF3 or SF5 showed similar antiparasitic activities, the cyclic ketone hub was more decisive both for the anti-parasitic activities and the selectivities for the parasites vs. normal cells. QSAR calculations confirmed the observed structure-activity relations and suggested structural variations for a further improvement of the antiparasitic activity. Docking studies based on DFT calculations revealed L. major pteridine reductase 1 as a likely molecular target protein of the title compounds.

Activity of Fluorinated Curcuminoids against Leishmania major and Toxoplasma gondii Parasites.

A new 3,4-difluorobenzylidene analog of curcumin, CDF, was recently reported, which demonstrated significantly enhanced bioavailability and in vivo anticancer activity compared with curcumin. For highlighting the antiparasitic behavior of CDF, we tested this compound together with its new O-methylated analog MeCDF against Leishmania major and Toxoplasma gondii parasites. Both CDF and MeCDF were tested in vitro against L. major and T. gondii. In addition, the in vitro cytotoxicity against Vero cells and macrophages was determined and selectivity indices were calculated. The DPPH radical scavenging activity assay was carried out in order to determine the antioxidant activity of the test compounds. Both compounds showed high activities against both parasite forms with EC50 values in the (sub-)micromolar range (0.35 to 0.8 µM for CDF, 0.31 to 1.2 µM for MeCDF). The higher activity of CDF against L. major amastigotes when compared with MeCDF can in parts be attributed to the antioxidant activity of CDF while MeCDF lacking any antioxidant activity was more active than CDF against T. gondii parasites. In conclusion, CDF and MeCDF are promising antiparasitic drug candidates due to their high activities against L. major and T. gondii parasites.

New Pyrano-4H-benzo[g]chromene-5,10-diones with Antiparasitic and Antioxidant Activities.

New pyranonaphthoquinone derivatives were synthesized and investigated for their activity against Trypanosoma brucei, Leishmania major, and Toxoplasma gondii parasites. The pentafluorophenyl derivative was efficacious against T. brucei with single digit micromolar EC50 values and against T. gondii with even sub-micromolar values. The 3-chloro-4,5-dimethoxyphenyl derivative showed an activity against amastigotes of Leishmania major parasites comparable to that of amphotericin B. In addition, antioxidant activities were observed for the bromophenyl derivatives, and their redox behavior was studied by cyclovoltammetry. Anti-parasitic and antioxidative activities of the new naphthoquinone derivatives appear uncorrelated.

New Antiparasitic Bis-Naphthoquinone Derivatives.

A series of bis-naphthoquinone derivatives prepared by condensation of aryl aldehydes with lawsone were tested for antiparasitic activities against Toxoplasma gondii and Trypanosoma brucei parasites. Monofluorophenyl derivative 1a, 3,4-difluorophenyl analog 1c and furyl compound 1l exhibited significant activity against T. gondii cells and appear to be new promising drug candidates against this parasite. The 3,4,5-trifluorophenyl derivative 1g and the isovanillyl derivative 1j displayed selective activity against Leishmania major amastigotes.

Evaluation of the antiparasitic activities of imidazol-2-ylidene-gold(I) complexes.

A series of cationic gold(I)-carbene complexes with various 4,5-diarylimidazolylidene ligands were either newly prepared or repurposed for testing against protozoal Leishmania major, Toxoplasma gondii, and Trypanosoma brucei parasites. The syntheses of the new complexes 1b and 1c were described. Ferrocene compound 1a showed the highest activities against L. major amastigotes and T. gondii and distinct selectivity for T. gondii cells when compared with the activity against nonmalignant Vero cells. The ferrocene derivatives 1a-c are generally more active against the L. major amastigotes and the T. gondii tachyzoites than the other tested anisyl gold complexes and the approved drugs atovaquone and amphotericin B. Compounds 1a and 1e showed the highest selectivities for L. major amastigotes. Compounds 1d and 1f showed the highest selectivities for L. major promastigotes; 1f was the most active compound against L. major promastigotes of this series of compounds. The 3,4,5-trimethoxyphenyl analog 1b also exhibited a much greater selectivity for T. b. brucei cells when compared with its activity against human HeLa cells.

Penicillin to prevent recurrent leg cellulitis.

BACKGROUND: Cellulitis of the leg is a common bacterial infection of the skin and underlying tissue. We compared prophylactic low-dose penicillin with placebo for the prevention of recurrent cellulitis. METHODS: We conducted a double-blind, randomized, controlled trial involving patients with two or more episodes of cellulitis of the leg who were recruited in 28 hospitals in the United Kingdom and Ireland. Randomization was performed according to a computer-generated code, and study medications (penicillin [250 mg twice a day] or placebo for 12 months) were dispensed by a central pharmacy. The primary outcome was the time to a first recurrence. Participants were followed for up to 3 years. Because the risk of recurrence was not constant over the 3-year period, the primary hypothesis was tested during prophylaxis only. RESULTS: A total of 274 patients were recruited. Baseline characteristics were similar in the two groups. The median time to a first recurrence of cellulitis was 626 days in the penicillin group and 532 days in the placebo group. During the prophylaxis phase, 30 of 136 participants in the penicillin group (22%) had a recurrence, as compared with 51 of 138 participants in the placebo group (37%) (hazard ratio, 0.55; 95% confidence interval [CI], 0.35 to 0.86; P=0.01), yielding a number needed to treat to prevent one recurrent cellulitis episode of 5 (95% CI, 4 to 9). During the no-intervention follow-up period, there was no difference between groups in the rate of a first recurrence (27% in both groups). Overall, participants in the penicillin group had fewer repeat episodes than those in the placebo group (119 vs. 164, P=0.02 for trend). There was no significant between-group difference in the number of participants with adverse events (37 in the penicillin group and 48 in the placebo group, P=0.50). CONCLUSIONS: In patients with recurrent cellulitis of the leg, penicillin was effective in preventing subsequent attacks during prophylaxis, but the protective effect diminished progressively once drug therapy was stopped. (Funded by Action Medical Research; PATCH I Controlled-Trials.com number, ISRCTN34716921.).

Antiparasitic Activity of Fluorophenyl-Substituted Pyrimido[1,2-a]benzimidazoles.

A series of fourteen pyrimido[1,2-a]benzimidazole compounds was prepared by straightforward heterocyclic chemistry and oxidation methods. The new pyrimidobenzimidazole derivative 2a with a 3-fluorophenyl substituent was identified as a new antiparasitic compound showing excellent activities against Leishmania major parasites. 2a was highly active against L. major promastigotes and amastigotes with EC50 values in the nanomolar concentration range. Compound 3b was less active than 2a against L. major, but more active against Toxoplasma gondii with considerable selectivity. Hence, two promising and selective antiparasitic drug candidates 2a and 3b for the treatment of two parasitic diseases were identified, which can be prepared by green chemistry methods using simple one-pot reactions and oxidation procedures, respectively.

Copper-Catalyzed Asymmetric Hydroboration Reaction of Novel Methylene Isoindolinone Compounds through Microwave Irradiation and Their Antileishmanial and Antitoxoplasma Activities.

The aim of this study was devoted into molecular docking calculations to discover the potential antileishmania and antitoxoplasma activities of newly synthesized compounds obtained by applying a practical and simple method under microwave irradiation. All these compounds were tested in vitro for their biological activity against Leishmania major promastigotes, amastigotes, and Toxoplasma gondii tachyzoites. Compounds 2a, 5a, and 5e were the most active against both L. major promastigotes and amastigotes, with IC50 values of less than 0.4 µM mL-1. Compounds 2c, 2e, 2h, and 5d had a strong antitoxoplasma activity of less than 2.1 µM mL-1 against T. gondii. We can conclude that aromatic methyleneisoindolinones are potently active against both L. major and T. gondii. Further studies for mode of action evaluation are recommended. Compounds 5c and 5b are the best drug candidates for antileishmania and antitoxoplasma due to their SI values being over 13. The docking studies of compounds 2a-h and 5a-e against pteridine reductase 1 and T. gondii enoyl acyl carrier protein reductase reveal that compound 5e may be an effective antileishmanial and antitoxoplasma drug discovery initiative.

Evaluation of the Antiparasitic and Antifungal Activities of Synthetic Piperlongumine-Type Cinnamide Derivatives: Booster Effect by Halogen Substituents.

A series of synthetic N-acylpyrrolidone and -piperidone derivatives of the natural alkaloid piperlongumine were prepared and tested for their activities against Leishmania major and Toxoplasma gondii parasites. Replacement of one of the aryl meta-methoxy groups by halogens such as chlorine, bromine and iodine led to distinctly increased antiparasitic activities. For instance, the new bromo- and iodo-substituted compounds 3 b/c and 4 b/c showed strong activity against L. major promastigotes (IC50 =4.5-5.8 µM). Their activities against L. major amastigotes were moderate. In addition, the new compounds 3 b, 3 c, and 4 a-c exhibited high activity against T. gondii parasites (IC50 =2.0-3.5 µM) with considerable selectivities when taking their effects on non-malignant Vero cells into account. Notable antitrypanosomal activity against Trypanosoma brucei was also found for 4 b. Antifungal activity against Madurella mycetomatis was observed for compound 4 c at higher doses. Quantitative structure-activity relationship (QSAR) studies were carried out, and docking calculations of test compounds bound to tubulin revealed binding differences between the 2-pyrrolidone and 2-piperidone derivatives. Microtubules-destabilizing effects were observed for 4 b in T. b. brucei cells.

Circulating adrenocorticotropic hormone (ACTH) and cortisol concentrations in normal, appropriate-for-gestational-age newborns versus those with sepsis and respiratory distress: Cortisol response to low-dose and standard-dose ACTH tests.

In this crossover study, we compared the peak responses of cortisol to low-dose (1 microg/1.73 m(2)) and standard-dose (250 microg/1.73 m(2)) adrenocorticotropic hormone (ACTH) stimulation tests in 90 full-term newborns (37 to 42 weeks gestational age, birthweight > 2,500 g, aged 4 to 7 days): 30 with sepsis syndrome, 30 with respiratory distress (RD) and 30 normal infants. Basal cortisol and ACTH were measured in a fasting venous sample. Serum cortisol concentrations were measured 30 minutes after low-dose ACTH and 60 minutes after standard-dose ACTH by radioimmunoassay (RIA). The mean basal circulating cortisol concentration and peak cortisol responses to low-dose and standard-dose ACTH tests were higher in stressed infants with sepsis and RD compared to normal. Basal but not ACTH-stimulated cortisol concentrations were significantly higher in newborns with sepsis versus those with RD. Circulating cortisol concentrations after the low-dose ACTH test were correlated significantly with those obtained after the standard-dose ACTH test (r = 0.814, P <.001). Clinical subgrouping of septic newborns showed that those with leukopenia (5/10 died) and with meningitis (6/12 died) had significantly lower basal and peak cortisol responses to the low-dose ACTH test (but not the standard-dose ACTH test) versus those with leukocytosis (3/20 died) and without meningitis (2/18 died), respectively. In addition, septic newborns who died had significantly lower circulating cortisol concentrations and lower cortisol responses to the low-dose ACTH test (but not the standard-dose test) versus those who survived the stress. On an individual basis, only 2 septic newborns (both died) had low basal cortisol levels (<5 microg/dL) and cortisol responses less than 15 microg/dL after the low-dose ACTH test. Four more septic newborns had basal cortisol above 5 microg/dl but cortisol responses below 20 microg/dL after the low-dose ACTH test. These 4 newborns (4/30) with inadequate adrenocortical response to low-dose ACTH during sepsis had high mortality (3/4 died) and represented a subgroup of septic newborns that should be diagnosed, using a low-dose ACTH test, and treated early. These data suggest that the low-dose ACTH test may be more disciminatory than the standard-dose test among babies under stress. Increasing the cut-point level of basal cortisol in stressed infants to the lowest level of cortisol response to low-dose ACTH in normal newborns, followed by the use of a low-dose ACTH test, appears to select some newborns who need and may improve on corticosteroid therapy. Further studies are required to investigate whether supplementation with stress doses of hydrocortisone may improve the outcome in these patients.

Serum leptin concentrations in children with type 1 diabetes mellitus: relationship to body mass index, insulin dose, and glycemic control.

Although obesity is a frequent feature of type 2 diabetes mellitus (DM), many patients with type 1 DM are prone to high body mass index (BMI). We measured serum leptin concentrations in a cohort of children (n = 55) with type 1 diabetes mellitus (DM), as well as their anthropometric parameters including BMI, skin fold thickness at multiple sites, and midarm circumference. Glycemic control was assessed by blood glucose (BG) monitoring before meals, and measurement of glycated hemoglobin (HbA1c) and insulin dose/kg/d was recorded. Dietary evaluation and assessment of caloric intake (kg/d) was performed by an expert dietitian. In the newly diagnosed children (n = 10) before initiation of insulin therapy, circulating leptin concentration was significantly lower (1.1 +/- 0.8 ng/dL) versus 5 days after insulin therapy (1.45 +/- 0.7 ng/dL). The decreased leptin level appears to be related to insulinopenia in these patients. In 45 children with type 1 DM on conventional therapy (2 doses of insulin mixture (NPH and regular) subcutaneous (SC) before breakfast and dinner for more than 2 years), serum leptin concentration was significantly higher (2.15 +/- 1 ng/dL) compared with age-matched normal children (1.3 +/- 1 ng/dL). Diabetic children were further divided into 2 groups according to their HbA1c level: group 1 with HbA1C less than 7.5% (less than 2 SD above the mean for normal population) (n = 29) and group 2 with HbA1c greater than 7.5%. (greater than 2 SD above the mean for normal population) (n = 16). Patients with a higher HbA1c level (group 2) had a higher leptin concentration (2.3 +/- 0.8 ng/dL), higher BMI (17.8 +/- 1.7), and were receiving higher insulin dose/kg (0.92 +/- 0.2 U/kg/d) compared with group 1 (lower HbA1c) (1.78 +/- 0.8 ng/dL, 16.7 +/- 1.5, and 0.59 +/- 0.2 U/kg/d, respectively). Group 2 patients had a higher incidence of late morning hypoglycemia (9/29) versus group 1 patients (2/16). Analysis of dietary intake showed that patients with a higher HbA1c (group 2) consumed more calories (73.5 +/- 10.5 kcal/kg/d) versus patients with lower HbA1c (64.2 +/- 8.7 kcal/kg/d). These findings pointed to the unphysiologic nature of injecting a mixture of insulin twice daily. To cover the relatively big lunch meal (40% to 50% of the total caloric intake in the Arab countries) and prevent afternoon hyperglycemia, there is a great tendency to increase NPH dose before breakfast. This, in turn, induces late-morning hypoglycemia and increases appetite and food intake at that time. Multiple regression analysis showed that circulating leptin concentrations (the dependent variable) were best correlated with the mean skinfold thickness (SFT), BMI, and caloric intake/kg/d (together they explained 65% of the variability in leptin concentrations). It appears that oversubstitution by insulin and increased food intake stimulate fat synthesis and subsequently BMI. Increased appetite and BMI contribute to increased leptin secretion and explains the higher leptin levels in undercontrolled diabetic children (higher circulating HbA1c concentrations) who were oversubstituted by insulin.

The effect of high-calorie diet on nutritional parameters of children with beta-thalassaemia major.

BACKGROUND: Impaired growth accompanying thalassaemia major poses diagnostic and therapeutic problems. AIM: To test the hypothesis that impaired growth of children with thalassaemia major might be corrected, partially or totally, by increasing their caloric intake. PATIENTS AND METHODS: In a prospective controlled study, thirty selected children with thalassaemia major and 30 normal age and sex-matched controls were recruited. The dietary intake of both groups was evaluated. Nutritional status was assessed by measuring the weight, body mass index (BMI), mid-arm circumference (MAC), triceps skin fold thickness (SFT) and serum albumin and insulin-like growth factor-I (IGF-I) concentrations. The thalassaemic group was then, randomly divided into two equal groups. One group was given 8 weeks of high-caloric diet (130-150% of the caloric recommendation for age and sex) and the other was given the normal caloric requirement. RESULTS: Initially the BMI, triceps SFT and MAC of children with thalassaemia were significantly decreased compared to those for the normal control group. IGF-I and albumin concentrations of thalassemic children before nutritional supplementation (69 +/- 20.5 ng/m and 3.65 +/- 0.67 g/dl, respectively) were significantly lower than those for normal age and sex-matched children (162.5 +/- 24 ng/ml and 4.29 +/- 0.66 g/dl, respectively). After nutritional supplementation for 8 weeks the MAC, SFT and BMI, IGF-I (88.4 +/- 27.3 ng/ml) and albumin concentrations (3.85 +/- 0.85 g/dl) increased significantly (P < 0.05) in the thalassaemic children given the supplementation compared to those without supplementation, however, they were still lower than normal children. CONCLUSIONS: Increased caloric dietary intake increased significantly IGF-I levels in thalassaemic children. This was accompanied with increased BMI, mid-arm circumference and skin fold thickness. Growth impairment of children with thalassaemia major, without endocrinopathy and/or cardiomyopathy, can be partially corrected by increasing caloric intake.