Induced pluripotent stem cell-derived human macrophages as an infection model for Leishmania donovani.

The parasite Leishmania donovani is one of the species causing visceral leishmaniasis in humans, a deadly infection claiming up to 40,000 lives each year. The current drugs for leishmaniasis treatment have severe drawbacks and there is an urgent need to find new anti-leishmanial compounds. However, the search for drug candidates is complicated by the intracellular lifestyle of Leishmania. Here, we investigate the use of human induced pluripotent stem cell (iPS)-derived macrophages (iMACs) as host cells for L. donovani. iMACs obtained through embryoid body differentiation were infected with L. donovani promastigotes, and high-content imaging techniques were used to optimize the iMACs seeding density and multiplicity of infection, allowing us to reach infection rates up to 70% five days after infection. IC50 values obtained for miltefosine and amphotericin B using the infected iMACs or mouse peritoneal macrophages as host cells were comparable and in agreement with the literature, showing the potential of iMACs as an infection model for drug screening.

Discovery of an orally active nitrothiophene-based antitrypanosomal agent.

Human African Trypanosomiasis (HAT), caused by Trypanosoma brucei gambiense and rhodesiense, is a parasitic disease endemic to sub-Saharan Africa. Untreated cases of HAT can be severely debilitating and fatal. Although the number of reported cases has decreased progressively over the last decade, the number of effective and easily administered medications is very limited. In this work, we report the antitrypanosomal activity of a series of potent compounds. A subset of molecules in the series are highly selective for trypanosomes and are metabolically stable. One of the compounds, (E)-N-(4-(methylamino)-4-oxobut-2-en-1-yl)-5-nitrothiophene-2-carboxamide (10), selectively inhibited the growth of T. b. brucei, T. b. gambiense and T. b. rhodesiense, have excellent oral bioavailability and was effective in treating acute infection of HAT in mouse models. Based on its excellent bioavailability, compound 10 and its analogs are candidates for lead optimization and pre-clinical investigations.

Jozibrevine D from Ancistrocladus ileboensis, the fifth alkaloid in a series of six possible atropo-diastereomeric naphthylisoquinoline dimers, showing antiparasitic and antileukemic activities.

A new dimeric naphthylisoquinoline alkaloid, jozibrevine D (4e), was isolated from the Central-African liana Ancistrocladus ileboensis. It is a Dioncophyllaceae-type metabolite, being R-configured at C-3 and lacking an oxygen function at C-6 in both isoquinoline moieties. The two identical monomers of jozibrevine D are symmetrically linked via the sterically constrained 3',3''-positions of the naphthalene units so that the central biaryl linkage is rotationally hindered and the alkaloid is, thus, C2-symmetric. With the two outer biaryl bonds being chiral, too, 4e possesses three consecutive stereogenic axes. The absolute stereostructure of the new compound was assigned by 1D and 2D NMR, ruthenium-mediated oxidative degradation, and electronic circular dichroism (ECD) spectroscopy. Jozibrevine D (4e) is the fifth discovered isomer in a series of six possible natural atropo-diastereomeric dimers. It shows potent, and selective, antiprotozoal activity against P. falciparum (IC50 = 0.14 µM), and it also exhibits good cytotoxic activities against drug-sensitive acute lymphoblastic CCRF-CEM leukemia cells (IC50 = 11.47 µM) and their multidrug-resistant CEM/ADR5000 subline (IC50 = 16.61 µM).

Discovery of Ircinianin Lactones B and C-Two New Cyclic Sesterterpenes from the Marine Sponge Ircinia wistarii.

Two new ircinianin-type sesterterpenoids, ircinianin lactone B and ircinianin lactone C (7 and 8), together with five known entities from the ircinianin compound family (1, 3-6) were isolated from the marine sponge Ircinia wistarii. Ircinianin lactones B and C (7 and 8) represent new ircinianin terpenoids with a modified oxidation pattern. Despite their labile nature, the structures could be established using a combination of spectroscopic data, including HRESIMS and 1D/2D NMR techniques, as well as computational chemistry and quantum-mechanical calculations. In a broad screening approach for biological activity, the class-defining compound ircinianin (1) showed moderate antiprotozoal activity against Plasmodium falciparum (IC50 25.4 µM) and Leishmania donovani (IC50 16.6 µM).

Discovery, Biosynthetic Origin, and Heterologous Production of Massinidine, an Antiplasmodial Alkaloid.

Bacteria of the genus Massilia represent an underexplored source of bioactive natural products. Here, we report the discovery of massinidine (1), a guanidine alkaloid with antiplasmodial activity, from these microbes. The unusual scaffold of massinidine is shown to originate from l-phenylalanine, acetate, and l-arginine. Massinidine biosynthesis genes were identified in the native producer and validated through heterologous expression in Myxococcus xanthus. Bioinformatic analyses indicate that the potential for massinidine biosynthesis is distributed in various proteobacteria.

Multimorbidity Among Adult Outpatients With Type 1 Diabetes in Germany.

AIM: The aim of this cross-sectional retrospective study was to estimate the prevalence of different physical and psychiatric disorders as well as multimorbidity in outpatients with type 1 diabetes (T1D) in Germany. METHODS: A total of 6967 adult patients with T1D from 958 general or diabetologist practices in Germany between January 2015 and December 2019 from the Disease Analyzer database (IQVIA) were included. The main outcome of the study was the prevalence of different diabetes-related and nondiabetes-related disorders within 12 months prior to the last outpatient visit. Multivariate logistic regression models were fitted with multimorbidity differently defined as >2, >3, >4, and >5 different disorders as a dependent variable and age, sex, glycated hemoglobin (HbA1c) values, and insulin pump therapy as impact variables. RESULTS: Mean age (standard deviation [SD]) was 45.3 (16.7) years; 42.9% were women, the mean HbA1c was 7.9% (SD: 1.4%). The most frequent disorder was arterial hypertension (31.2%), followed by dyslipidemia (26.4%), dorsalgia (20.4%), diabetic neuropathy (17.3%), and depression (14.6%). The proportion of thyroid gland disorders, retinopathy, urethritis, iron deficiency anemia, and psychiatric disorders was higher in women than in men. Hypertension and mental and behavioral disorders due to the use of tobacco were higher in men. On average, each patient was diagnosed with 3.1 different disorders. Age had the strongest association with multimorbidity, followed by HbA1c value and female sex. CONCLUSION: In summary, patients with T1D are often multimorbid, and the multimorbidity is associated with higher gender, female sex, and high HbA1c values. Understanding all of these factors can help practitioners create a risk profile for every patient.

Boswellic Acids Show In Vitro Activity against Leishmania donovani.

In continuation of our search for leads from medicinal plants against protozoal pathogens, we detected antileishmanial activity in polar fractions of a dichloromethane extract from Boswellia serrata resin. 11-keto-ß-boswellic acid (KBA) could be isolated from these fractions and was tested in vitro against Leishmania donovani axenic amastigotes along with five further boswellic acid derivatives. 3-O-acetyl-11-keto-ß-boswellic acid (AKBA) showed the strongest activity with an IC50 value of 0.88 µM against axenic amastigotes but was inactive against intracellular amastigotes in murine macrophages.

Synthesis and Biological Evaluation of Natural-Product-Inspired, Aminoalkyl-Substituted 1-Benzopyrans as Novel Antiplasmodial Agents.

Herein, relationships between the structures of 1-aminoethyl-substituted chromenes and their antimalarial activities were thoroughly investigated. At first, the methyl moiety in the side chain was removed to eliminate chirality. The hydrogenation state of the benzopyran system, the position of the phenolic OH moiety, and the distance of the basic amino moiety toward both aromatic rings were varied systematically. 1-Benzopyran-5-ol 8b (IC50 = 10 nM), 1-benzopyran-7-ol 9c (IC50 = 38 nM), and the aminoalcohol 19c (IC50 = 17 nM) displayed antiplasmodial activity with IC50 values below 50 nM. To identify the mechanism of action, inhibition of three key enzymes by 9c was investigated. 9c was not able to reduce the number of Plasmodia in erythrocytes of mice. This low in vivo activity was explained by fast clearance from blood plasma combined with rapid biotransformation of 9c. Three main metabolites of 9c were identified by liquid chromatography-mass spectrometry (LC-MS) methods.

Quest for a potent antimalarial drug lead: Synthesis and evaluation of 6,7-dimethoxyquinazoline-2,4-diamines.

Quinazolines have long been known to exert varied pharmacologic activities that make them suitable for use in treating hypertension, viral infections, tumors, and malaria. Since 2014, we have synthesized approximately 150 different 6,7-dimethoxyquinazoline-2,4-diamines and evaluated their antimalarial activity via structure-activity relationship studies. Here, we summarize the results and report the discovery of 6,7-dimethoxy-N4-(1-phenylethyl)-2-(pyrrolidin-1-yl)quinazolin-4-amine (20, SSJ-717), which exhibits high antimalarial activity as a promising antimalarial drug lead.

Activation, Structure, Biosynthesis and Bioactivity of Glidobactin-like Proteasome Inhibitors from Photorhabdus laumondii.

The glidobactin-like natural products (GLNPs) glidobactin A and cepafungin I have been reported to be potent proteasome inhibitors and are regarded as promising candidates for anticancer drug development. Their biosynthetic gene cluster (BGC) plu1881-1877 is present in entomopathogenic Photorhabdus laumondii but silent under standard laboratory conditions. Here we show the largest subset of GLNPs, which are produced and identified after activation of the silent BGC in the native host and following heterologous expression of the BGC in Escherichia coli. Their chemical diversity results from a relaxed substrate specificity and flexible product release in the assembly line of GLNPs. Crystal structure analysis of the yeast proteasome in complex with new GLNPs suggests that the degree of unsaturation and the length of the aliphatic tail are critical for their bioactivity. The results in this study provide the basis to engineer the BGC for the generation of new GLNPs and to optimize these natural products resulting in potential drugs for cancer therapy.

Unusual derivatives from Hypericum scabrum.

Three new compounds (1-3) with unusual skeletons were isolated from the n-hexane extract of the air-dried aerial parts of Hypericum scabrum. Compound 1 represents the first example of an esterified polycyclic polyprenylated acylphloroglucinol that features a unique tricyclo-[4.3.1.11,4]-undecane skeleton. Compound 2 is a fairly simple MPAP, but with an unexpected cycloheptane ring decorated with prenyl substituents, and compound 3 has an unusual 5,5-spiroketal lactone core. Their structures were determined by extensive spectroscopic and spectrometric techniques (1D and 2D NMR, HRESI-TOFMS). Absolute configurations were established by ECD calculations, and the absolute structure of 2 was confirmed by a single crystal determination. Plausible biogenetic pathways of compounds 1-3 were also proposed. The in vitro antiprotozoal activity of the compounds against Trypanosoma brucei rhodesiense and Plasmodium falciparum and cytotoxicity against rat myoblast (L6) cells were determined. Compound 1 showed a moderate activity against T. brucei and P. falciparum, with IC50 values of 3.07 and 2.25 µM, respectively.

Will oral semaglutide be a game-changer in the management of type 2 diabetes in primary care?

GLP-1 receptor agonists (GLP-1RAs) are recommended for patients with type 2 diabetes (T2D), particularly those at high cardiovascular risk. Oral semaglutide is the first oral GLP-1RA. In clinical trials, oral semaglutide 14 mg reduced mean HbA1c by approximately 1.1-1.5% and reduced body weight by up to 5 kg. These changes were significantly greater compared with empagliflozin, sitagliptin and liraglutide (p < 0.05 for estimated treatment differences at 52 weeks in patients on treatment without rescue medication use). The most common side effects were gastrointestinal, mainly mild-to-moderate and transient nausea. Oral semaglutide may change the paradigm of T2D treatment in primary care.

Preparation of new 1,3-dibenzyl tetrahydropyridinylidene ammonium salts and their antimicrobial and anticellular activities.

New 1,3 dibenzyl -tetrahydropyridinylidene ammonium salts have been prepared from unsubstituted or N-benzylated tetrahydropyridinylidene ammonium salts. The antiplasmodial and antitrypanosomal activities as well as their cytotoxic effects were determined using microplate assays. In addition, their activities against two gram positive and two gram negative bacteria strains and a yeast strain were examined. Furthermore, anticancer effects against two cell lines were investigated. Physicochemical parameters were calculated and structure-activity-relationships discussed. One compound showed antiplasmodial activity against a multiresistant strain of Plasmodium falciparum in subnanomolar concentration. Antitrypanosomal activities were detected in low nanomolar concentrations. A single compound was active against grampositive and gramnegative bacteria, as well as yeast. One compound inhibited the growth of a HCT cell line in low concentration.

Activity of diphenyl ether benzyl amines against Human African Trypanosomiasis.

Insect-borne parasite Trypanosoma brucei plagues humans and other animals, eliciting the disease Human African trypanosomiasis, also known as African sleeping sickness. This disease poses the biggest threat to the people in Sub-Saharan Africa. Given the high toxicity and difficulties with administration of currently available drugs, a novel treatment is needed. Building on known Human African trypanosomiasis structure-activity relationship (SAR), we now describe a number of functionally simple diphenyl ether analogs which give low micromolar activity (IC50 = 0.16-0.96 µM) against T. b. rhodesiense. The best compound shows favorable selectivity against the L6 cell line (SI = 750) and even greater selectivity (SI = 1200) against four human cell lines. The data herein provides direction for the ongoing optimization of antitrypanosomal diphenyl ethers.

Antiprotozoal Activity of Turkish Origanum onites Essential Oil and Its Components.

Essential oil of Origanum species is well known for antimicrobial activity, but only a few have been evaluated in narrow spectrum antiprotozoal assays. Herein, we assessed the antiprotozoal potential of Turkish Origanum onites L. oil and its major constituents against a panel of parasitic protozoa. The essential oil was obtained by hydrodistillation from the dried herbal parts of O. onites and analyzed by Gas Chromatography-Flame Ionization Detector (GC-FID) and Gas Chromatography coupled with Mass Spectrometry (GC-MS). The in vitro activity of the oil and its major components were evaluated against Trypanosoma brucei rhodesiense, T. cruzi, Leishmania donovani, and Plasmodium falciparum. The main component of the oil was identified as carvacrol (70.6%), followed by linalool (9.7%), p-cymene (7%), γ-terpinene (2.1%), and thymol (1.8%). The oil showed significant in vitro activity against T. b. rhodesiense (IC50 180 ng/mL), and moderate antileishmanial and antiplasmodial effects, without toxicity to mammalian cells. Carvacrol, thymol, and 10 additional abundant oil constituents were tested against the same panel; carvacrol and thymol retained the oil's in vitro antiparasitic potency. In the T. b. brucei mouse model, thymol, but not carvacrol, extended the mean survival of animals. This study indicates the potential of the essential oil of O. onites and its constituents in the treatment of protozoal infections.

A Near-Complete Series of Four Atropisomeric Jozimine A2-Type Naphthylisoquinoline Dimers with Antiplasmodial and Cytotoxic Activities and Related Alkaloids from Ancistrocladus abbreviatus.

Three new naphthylisoquinoline dimers, jozibrevines A-C (1a-c), were isolated from the West African shrub Ancistrocladus abbreviatus, along with the known dimer jozimine A2 (1d). The two molecular moieties of 1a-d are coupled via the sterically constrained 3',3″-positions of their two naphthalene units, so that the central biaryl linkage is rotationally hindered. With the two outer axes also being chiral, 1a-d possess three consecutive stereogenic axes. The four isolated dimers all have the same constitutions and identical absolute configurations at the four stereogenic centers, but differ by their axial chirality. They belong to the extremely small class of Dioncophyllaceae-type naphthylisoquinoline dimers, i.e., being devoid of oxygen functions at C-6 and bearing the R-configuration at C-3 in their isoquinoline portions. Besides these dimers, the plant produces predominantly typical Ancistrocladaceae-type monomeric compounds, i.e., with the S-configuration at C-3 and an oxygen function at C-6, such as the new ancistrobrevines K (5) and L (6). Furthermore, a new hybrid-type (i.e., mixed Ancistrocladaceae/Dioncophyllaceae-type) alkaloid was identified, named ancistrobrevine M (7), which is 3R-configured and 6-oxygenated. Remarkable was the discovery of its "inverse hybrid-type" counterpart, dioncoline A (8). It is the as yet only known 3S-configured naphthylisoquinoline lacking an O-functionality at C-6. The new jozibrevines A-C (1a-c) exhibited pronounced antiplasmodial activities in the submicromolar range, with 1a being the most potent compound (IC50, 0.012 µM). Furthermore, jozimine A2 (1d) showed cytotoxicity against human colon carcinoma (HT-29), fibrosarcoma (HT1080), and multiple myeloma (MM.1S) cancer cells, displaying IC50 values of 12.0, 9.0, and 5.0 µM, respectively, whereas jozibrevines A (1a) and B (1b) were nontoxic in this concentration range.

Ealamines A-H, a Series of Naphthylisoquinolines with the Rare 7,8'-Coupling Site, from the Congolese Liana Ancistrocladus ealaensis, Targeting Pancreatic Cancer Cells.

From the twigs and leaves of the Central African liana Ancistrocladus ealaensis (Ancistrocladaceae), a series of ten 7,8'-coupled naphthylisoquinoline alkaloids were isolated, comprising eight new compounds, named ealamines A-H (4a, 4b, 5-10), and two known ones, 6-O-demethylancistrobrevine A (11) and yaoundamine A (12), which had previously been found in related African Ancistrocladus species. Only one of the new compounds within this series, ealamine H (10), is a typical Ancistrocladaceae-type alkaloid, with 3S-configuration at C-3 and an oxygen function at C-6, whereas seven of the new alkaloids are the first 7,8'-linked "hybrid-type" naphthylisoquinoline alkaloids, i.e., 3R-configured and 6-oxygenated in the tetrahydroisoquinoline part. The discovery of such a broad series of 7,8'-coupled naphthyltetrahydroisoquinolines is unprecedented, because representatives of this subclass of alkaloids are normally found in Nature quite rarely. The stereostructures of the new ealamines were assigned by HRESIMS, 1D and 2D NMR, oxidative degradation, and experimental and quantum-chemical ECD investigations, and-in the case of ealamine A (4a)-also confirmed by X-ray diffraction analysis. Ealamines A-D exhibited distinct-and specific-antiplasmodial activities, and they displayed pronounced preferential cytotoxic effects toward PANC-1 human pancreatic cancer cells in nutrient-deprived medium, without causing toxicity under normal, nutrient-rich conditions, with ealamine C (5) as the most potent agent.

Ancistrobrevines E-J and related naphthylisoquinoline alkaloids from the West African liana Ancistrocladus abbreviatus with inhibitory activities against Plasmodium falciparum and PANC-1 human pancreatic cancer cells.

From the roots of the West African liana Ancistrocladus abbreviatus (Ancistrocladaceae), ten new naphthylisoquinoline alkaloids (7a, 7b, 8a, 8b, and 9-14), displaying three different coupling types (5,1', 5,8', and 7,8'), were isolated, among them a series of five 5,1'-linked representatives and four metabolites belonging to the rare group of 7,8'-coupled alkaloids. Two of the alkaloids, the ancistrobrevines I (13) and J (14), are only the fourth and fifth examples of 7,8'-linked naphthyldihydroisoquinolines ever found in nature. The stereostructures of the new plant metabolites were determined by spectroscopic, chemical (oxidative degradation), and chiroptical (electronic circular dichroism) methods. For the assignment of the axial configuration of 13 and 14 relative to the stereocenter at C-3, which is too far away for significant NOE long-range interactions, these 7,8'-coupled naphthyldihydroisoquinolines were stereoselectively converted into the respective cis-configured tetrahydroisoquinoline analogs. The newly generated 'auxiliary' stereocenter at C-1 permitted decisive NOE interactions between the isoquinoline and the naphthalene parts, and thus a reliable attribution of the axial configuration of 13 and 14. In addition, five known compounds (3, 5, 16, 17, and 20), previously discovered in related African and Asian Ancistrocladus species, have now for the first time been identified in A. abbreviatus. All of these alkaloids are S-configured at C-3 and bear an oxygen function at C-6, and are, thus, typical Ancistrocladaceae-type compounds. Some of the alkaloids of A. abbreviatus exhibited promising activities against the malaria parasite Plasmodium falciparum and PANC-1 human pancreatic cancer cells.

Synthesis of Jacaranone-Derived Nitrogenous Cyclohexadienones and Their Antiproliferative and Antiprotozoal Activities.

The cytotoxic and antiprotozoal activities of the phytoquinoide, jacaranone, and related compounds have been an ongoing topic in recent drug discovery. Starting from the natural product-derived cyclohexadienone scaffold, a series of nitrogen-containing derivatives were synthesized and subsequently evaluated for their antiproliferative and antiprotozoal activity. Anticancer potency was analyzed using different types of cancer cell lines: MDA-MB-231 breast cancer, CCRF-CEM leukemia, HCT-116 colon cancer, U251 glioblastoma, and, in addition, non-tumorigenic MRC-5 lung fibroblasts. Antiproliferative activities at micromolar concentrations could be shown. Antiprotozoal activity was assessed against Plasmodium falciparum NF54 and Trypanosoma brucei rhodesiense STIB900. For all compounds, selectivity indices (SI) were calculated based on assessed cytotoxicity towards L6 cells. In addition, the structure-activity-relationships and physicochemical parameters of these compounds are discussed.

Methionine-Containing Rhabdopeptide/Xenortide-like Peptides from Heterologous Expression of the Biosynthetic Gene Cluster kj12ABC in Escherichia coli.

Seven new methionine-containing rhabdopeptide/xenortide-like peptides (1-7) were identified from Escherichia coli expressing the rhabdopeptide/xenortide-like peptide biosynthetic gene cluster kj12ABC from Xenorhabdus KJ12.1. Their structures were elucidated by detailed HPLC-HR-MS/MS analysis and confirmed by chemical synthesis. Bioactivity tests of these first rhabdopeptide/xenortide-like peptide derivatives (2-7) showing methionine building blocks compared to the usually found derivatives containing exclusively hydrophobic amino acids such as valine, leucine, or phenylalanine revealed good activities of 2-7 against protozoan parasites and no cytotoxicity against mammalian L6 cells.