Publications by authors named "Heinrich C Hoppe"

Article Synopsis
  • Quinoline-urea-benzothiazole hybrid compounds showed promising anti-parasitic activities against the 3D7 chloroquine-sensitive strain with effective concentrations ranging from 0.33 to 0.97 μM.
  • Many hybrids performed comparably to chloroquine in inhibiting β-haematin formation, with two compounds showing slightly better efficacy than chloroquine.
  • Molecular docking studies indicated that some compounds had higher binding energies than known drugs like chloroquine and pentamidine, and stability was confirmed through 100 ns simulations, indicating potential for effective enzyme targeting.
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Compounds containing arylpyrrole-, 1,2,4-triazole- and hydrazone structural frameworks have been widely studied and demonstrated to exhibit a wide range of pharmacological properties. Herein, an exploratory series of new 1,2,4-triazole derivatives designed by amalgamation of arylpyrrole and 1,2,4-triazole structural units via a hydrazone linkage is reported. The synthesised compounds were tested in vitro for their potential activity against Mycobacterium tuberculosis (MTB) H Rv strain.

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Herein we report the synthesis of 21 novel small molecules inspired by metronidazole and Schiff base compounds. The compounds were evaluated against Trichomonas vaginalis and cross-screened against other pathogenic protozoans of clinical relevance. Most of these compounds were potent against T.

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Previous research shows that the root and bark extracts of Euclea natalensis have antiplasmodial activity, but the leaves have not been examined yet. This study investigated the phytochemical, antiplasmodial, and cytotoxic properties of the plant leaves. The activity against 3D7 Plasmodium falciparum was determined using the parasite lactate dehydrogenase assay, and the cytotoxicity against Vero and HeLa cells was evaluated using the MTT and resazurin assays, respectively.

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Article Synopsis
  • Researchers developed pyrrolo[2,3-d]pyrimidines as potential inhibitors for the PfCDPK4 enzyme linked to malaria-causing P. falciparum!
  • A small selection of these compounds was tested, showing effective inhibition against PfCDPK4 (IC values between 0.210-0.530 μM) and PfCDPK1 (IC = 0.589 μM)!
  • The findings will help improve the molecular model for better prediction of activity against PfCDPK4.
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is used in Zulu traditional medicine as an antimalarial remedy. A moderate antiplasmodial activity was previously reported for extracts of the plant against D10 . This study aimed to identify the phytochemicals responsible for the antiplasmodial activity of the leaf extract.

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HPPK, which directly precedes DHPS in the folate biosynthetic pathway, is a promising but chronically under-exploited anti-microbial target. Here we report the identification of new HPPK inhibitors, offering potential for new resistance circumventing therapies as well as avenues for diversifying the current HPPK inhibitor space.

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Human African trypanosomiasis is a vector-borne tropical disease of African origin. Presently, due to human migration and climate change, the disease might present global health and economic burdens as current chemotherapy of trypanosomiasis remains a challenge due to limited existing drugs, which are of poor efficacy, cause severe adverse events and are very costly. Recently, Beteck and co-workers identified a small library of 1,3,6-substituted non-fluoroquinolones that showed moderate to weak trypanocidal activity without cytotoxic effects.

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Previous results indicated that the methanol extract of has antiplasmodial activity but no compounds have ever been isolated from the plant. Therefore, this study aimed to investigate the phytochemical and antiplasmodial properties of the plant. The methanol leaf extract of inhibited at 50 µg/mL (> 80% inhibition) and was not cytotoxic against HeLa cells.

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Ethnobotanical surveys indicate that the Masai and Kikuyu in Kenya, the Venda in South Africa, and the Gumuz people of Ethiopia use for the treatment of malaria. The present study aimed to investigate the phytochemical and antiplasmodial properties of the plant leaves. The bioactive compounds were isolated using chromatographic techniques.

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A tailored series of coumarin-based ferrocenyl 1,3-oxazine hybrid compounds was synthesized and investigated for potential antiparasitic activity, drawing inspiration from the established biological efficacy of the constituent chemical motifs. The structural identity of the synthesized compounds was confirmed by common spectroscopic techniques: NMR, HRMS and IR. Biological evaluation studies reveal that the compounds exhibit higher in vitro antiparasitic potency against the chemosensitive malarial strain (3D7 ) over the investigated trypanosomiasis causal agent ( 427) with mostly single digit micromolar IC values.

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A rationally designed series of 2-(N-cyclicamino)quinolines coupled with methyl (E)-3-(2/3/4-aminophenyl)acrylates was synthesized and subjected to in vitro screening bioassays for potential antiplasmodial and antitrypanosomal activities against a chloroquine-sensitive (3D7) strain of Plasmodium falciparum and nagana Trypanosoma brucei brucei 427, respectively. Substituent effects on activity were evaluated; meta-acrylate 24 and the ortho-acrylate 29 exhibited the highest antiplasmodial (IC  = 1.4 µM) and antitrypanosomal (IC  = 10.

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The cell wall of () has a unique structural organisation, comprising a high lipid content mixed with polysaccharides. This makes cell wall a formidable barrier impermeable to hydrophilic agents. In addition, during host infection, resides in macrophages within avascular necrotic granulomas and cavities, which shield the bacterium from the action of most antibiotics.

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Several classes of antimalarial drugs are currently available, although issues of toxicity and the emergence of drug resistant malaria parasites have reduced their overall therapeutic efficiency. Quinoline based antiplasmodial drugs have unequivocally been long-established and continue to inspire the design of new antimalarial agents. Herein, a series of mono- and bisquinoline methanamine derivatives were synthesised through sequential steps; Vilsmeier-Haack, reductive amination, and nucleophilic substitution, and obtained in low to excellent yields.

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Malaria elimination can benefit from time and cost-efficient approaches for antimalarials such as drug repurposing. In this work, 796 DrugBank compounds were screened against 36 Plasmodium falciparum targets using QuickVina-W. Hits were selected after rescoring using GRaph Interaction Matching (GRIM) and ligand efficiency metrics: surface efficiency index (SEI), binding efficiency index (BEI) and lipophilic efficiency (LipE).

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A series of N-benzylated phosphoramidate esters, containing a 3,4-dihydroxyphenyl Mg-chelating group, has been synthesised in five steps as analogues of fosmidomycin, a Plasmodium falciparum 1-deoxy-1-d-xylulose-5-phosphate reductoisomerase (PfDXR) inhibitor. The 3,4-dihydroxyphenyl group effectively replaces the Mg-chelating hydroxamic acid group in fosmidomycin. The compounds showed very encouraging anti-parasitic activity with IC values of 5.

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As part of an ongoing study of natural products from local medicinal plants, the methanol extract of stem bark of Sond was investigated for biological activity. Column chromatography and preparative thin-layer chromatography were used to isolate lupeol (), raucaffricine (), -methylsarpagine (), and spegatrine (). The crude extract, fractions and isolated compounds were tested for anti-oxidant, antitrypanosomal and anti-proliferation activities.

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Synthetic pathways have been developed to access a series of N-benzylated phosphoramidic acid derivatives as novel, achiral analogues of the established Plasmodium falciparum 1-deoxy-d-xylulose-5-phosphate reductase (PfDXR) enzyme inhibitor, FR900098. Bioassays of the targeted compounds and their synthetic precursors have revealed minimal antimalarial activity but encouraging anti-trypanosomal activity - in one case with an IC value of 5.4 µM against Trypanosoma brucei, the parasite responsible for Nagana (African cattle sleeping sickness).

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In this study, we synthesized novel nitro quinolone-based compounds and tested them in vitro against a panel of Gram-positive and Gram-negative pathogens including Mycobacterium tuberculosis (MTB), Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumonia, Staphylococcus aureus, and Escherichia coli for antibacterial activities and also against HeLa cells for overt cytotoxicity. Compound 8e was identified as a non-toxic, potent hit with selective activity (MIC  ˂ 0.24 µm) against MTB.

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The conjugation of organometallic complexes to known bioactive organic frameworks is a proven strategy revered for devising new drug molecules with novel modes of action. This approach holds great promise for the generation of potent drug leads in the quest for therapeutic chemotypes with the potential to overcome the development of clinical resistance. Herein, we present the in vitro antiplasmodial and antiproliferative investigation of ferrocenyl α-aminocresol conjugates assembled by amalgamation of the organometallic ferrocene unit and an α-aminocresol scaffold possessing antimalarial activity.

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With an intention of identifying chalcone derivatives exhibiting anti-protozoal activity, a cohort of relatively unexplored arylpyrrole-based chalcone derivatives were synthesized in moderate to good yields. The resultant compounds were evaluated in vitro for their potential activity against a cultured 427 strain. Several compounds displayed mostly modest in vitro anti-trypanosomal activity with compounds and emerging as active candidates with IC values of 4.

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Ethnopharmacological Relevance: The dicotyledonous plant Piptadeniastrum africanum (hook.f.) Brennan (Fabaceae) is used in traditional medicine to treat various human complaints including bronchitis, coughing, urino-genital ailments, meningitis, abdominal pain, treatment of wounds, malaria and gastrointestinal ailments, and is used as a purgative and worm expeller.

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The regulation of human Arf1 GTPase activity by ArfGEFs that stimulate GDP/GTP exchange and ArfGAPs that mediate GTP hydrolysis has attracted attention for the discovery of Arf1 inhibitors as potential anti-cancer agents. The malaria parasite Plasmodium falciparum encodes a Sec7 domain-containing protein - presumably an ArfGEF - and two putative ArfGAPs, as well as an Arf1 homologue (PfArf1) that is essential for blood-stage parasite viability. However, ArfGEF and ArfGAP-mediated activation/deactivation of PfArf1 has not been demonstrated.

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A series of N,N'-bis[4-hydroxycoumarin-3-yl)ethylidene]-2,3-dihydroxysuccino-hydrazides, containing 4-hydroxycoumarin, hydrazine and tartaric acid moieties, have been prepared and examined for possible biological activity. Several of these compounds exhibit promising HIV-1 integrase inhibition (IC = 3.5 μM), and anti-T.

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