Thomas J. Schmidt

University of Münster | WWU · Institute of Pharmaceutical Biology and Phytochemistry

Leishmaniasis, a parasitic disease that represents a threat to the life of millions of people around the globe, is currently lacking effective treatments. We have previously reported on the antileishmanial activity of a series of synthetic 2-phenyl-2,3-dihydrobenzofurans and some qualitative structure–activity relationships within this set of neoli...

The oleo-gum resin of Commiphora myrrha (Nees) Engl. has a long history of medicinal use, although many of its constituents are still unknown. In the present investigation, 34 secondary metabolites were isolated from myrrh resin using different chromatographic techniques (silica flash chromatography, CPC, and preparative HPLC) and their structures...

Cutaneous leishmaniasis (CL) is classified as a neglected tropical disease by the World Health Organization. As the standard drugs for the treatment of this disease suffer from severe unwanted effects, new effective and safe therapeutic options are required. In our previous work, Arnica tincture showed promising antileishmanial effects in vitro and...

Leishmaniasis may occur in three different clinical forms, namely, visceral, mucocutaneous and cutaneous, which are caused by different species of trypanosomatid protozoans of the genus Leishmania. Pentavalent antimonials are the leading treatment for cutaneous leishmaniasis despite the hepatic, renal, and cardiac toxicity. In addition, the respons...

Arnica tincture is a traditional herbal medicine used to treat blunt injuries, e.g., bruises and squeezes. In addition, a potential new use in the treatment of cutaneous leishmaniasis is currently under investigation. Therefore, detailed information about the dermal absorption of the tincture and especially its bioactive constituents, sesquiterpene...

The transcription factor MYB is expressed predominantly in hematopoietic progenitor cells, where it plays an essential role in the development of most lineages of the hematopoietic system. In the myeloid lineage, MYB is known to cooperate with members of the CCAAT box/enhancer binding protein (C/EBP) family of transcription factors. MYB and C/EBPs...

Arnica tincture is a herbal medicinal preparation with anti-inflammatory activity which is used traditionally for the topical treatment of blunt injuries as well as rheumatic muscle and joint complaints. Its main bioactive constituents are sesquiterpene lactones (STLs) of the helenalin and 11α,13-dihydrohelenalin types. Besides the mentioned activi...

The parasite Trypanosoma brucei (T. brucei) is responsible for human African trypanosomiasis (HAT) and the cattle disease “Nagana” which to this day cause severe medical and socio-economic issues for the affected areas in Africa. So far, most of the available treatment options are accompanied by harmful side effects and are constantly challenged by...

Buxus sempervirens L. is a common ornamental plant in southern and central Europe, and has been used ethopharmacologically against a wide variety of diseases due to it containing nor-triterpene alkaloids of the nor-cycloartane type. Recently, we demonstrated the interesting antiprotozoal potential of some of these compounds. To characterize the tem...

Various nor-triterpene alkaloids of Buxus (B.) sempervirens L. have shown remarkable in vitro activity against the causative agents of tropical malaria and East African sleeping sick-ness. To identify further antiprotozoal compounds of this plant, 20 different fractions of B. sem-pervirens L., exhibiting a wide range of in vitro bioactivity, were a...

On the basis of the finding that various aminoalkyl-substituted chromene and chromane derivatives possess strong and highly selective in vitro bioactivity against Plasmodium falciparum, the pathogen responsible for tropical malaria, we performed a structure–activity relationship study for such compounds. With structures and activity data of 52 cong...

Transcription factor MYB has recently emerged as a promising drug target for the treatment of acute myeloid leukemia (AML). Here, we have characterized a group of natural sesquiterpene lactones (STLs), previously shown to suppress MYB activity, for their potential to decrease AML cell proliferation. Unlike what was initially thought, these compound...

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-β-boswellic acid (KBA) could be isolated from these fractions and was tested in vitro against Leishmania donovani axenic amastigotes alo...

Malaria and human African trypanosomiasis (HAT; sleeping sickness) are life-threatening tropical diseases caused by protozoan parasites. Due to limited therapeutic options, there is a compelling need for new antiprotozoal agents. In a previous study, O-tigloylcyclovirobuxeine-B was recovered from a B. sempervirens L. (common box; Buxaceae) leaf ext...

As part of our studies on antiprotozoal activity of approved herbal medicinal products, we previously found that a commercial tincture from Salvia officinalis L. (common Sage, Lamiaceae) possesses high activity against Trypanosoma brucei rhodesiense (Tbr), causative agent of East African Human Trypanosomiasis. We have now investigated in detail the...

Onchocerciasis is a filarial disease caused by Onchocerca volvulus and transmitted through the bite of a blackfly of the genus Simulium. The microfilaricidal drug ivermectin has long been relied on to treat onchocerciasis. Nowadays, the focus is on the complete elimination of the disease through the development of macro-filaricidal drugs. In this s...

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 a...

In the course of our studies on antiprotozoal natural products and following our recent discovery that certain aminosteroids and aminocycloartanoid compounds from Holarrhena africana A. DC. (Apocynaceae) and Buxus sempervirens L. (Buxaceae), respectively, are strong and selective antitrypanosomal agents, we have extended these studies to another pl...

Ifenprodil (1) is a potent GluN2B-selective N-methyl-d-aspartate (NMDA) receptor antagonist that is used as a cerebral vasodilator and has been examined in clinical trials for the treatment of drug addiction, idiopathic pulmonary fibrosis, and COVID-19. To correlate biological data with configuration, all four ifenprodil stereoisomers were prepared...

The increasing drug resistance of malaria parasites challenges the treatment of this life-threatening disease. Consequently, the development of innovative and effective antimalarial drugs is inevitable. O-tigloylcyclovirobuxeine-B, a nor-cycloartane alkaloid from Buxus sempervirens L., has shown promising and selective in vitro activity in previous...

Leishmaniasis, a neglected tropical disease caused by parasites of the genus Leishmania, causes a serious burden of disease around the world, represents a threat to the life of millions of people, and therefore is a major public health problem. More effective and non-toxic new treatments are required, especially for visceral leishmaniasis, the most...

The perhydroquinoline‐based KOR agonist (±)‐4 was prepared in a diastereoselective synthesis. The first key step of the synthesis was the diastereoselective hydrogenation of silyl ether (±)‐9 affording cis,cis‐configured perhydroquinoline (±)‐10. Nucleophilic substitution of (±)‐12 with pyrrolidine resulted in the desired cis,trans‐configured pyrro...

As part of our ongoing search for antiprotozoal natural products from plants, we examined different resins from the Burseraceae family. The dichloromethane extract obtained from myrrh, the oleo-gum-resin of Commiphora species, showed promising in vitro activity against Plasmodium falciparum with an IC50 value of 1 µg/mL. Bioactivity-guided fraction...

Ethnopharmacological relevance Extracts from Cranberry fruits (Vaccinium macrocarpon) are traditionally used against urinary tract infections, mainly due to antiadhesive activity against uropathogenic E. coli (UPEC), but the exact mode of action and compounds, responsible for the activity, are unknown. Aim of the study i. To investigate if cranber...

On behalf of my Section Editor-in-Chief co-author colleagues I am pleased to announce a Special Issue to commemorate the recent publication of Molecules’ 20,000th paper [...]

Parasitic infections like leishmaniasis and trypanosomiasis remain as a worldwide concern to public health. Improvement of the currently available drug discovery pipelines for those diseases is therefore mandatory. We have recently reported on the antileishmanial and antitrypanosomal activity of a set of cinnamate esters where we identified several...

Protozoal infections are still a global health problem, threatening the lives of millions of people around the world, mainly in impoverished tropical and sub‐tropical regions. Thus, in view of the lack of efficient therapies and increasing resistances against existing drugs, this study describes the antiprotozoal potential of synthetic cinnamate es...

In the course of our investigations on the antitrypanosomal potential of sesquiterpene lactones (STL), we have recently reported on the exceptionally strong activity of 4,15-iso-Atriplicolide tiglate, which demonstrated an IC50 value of 15 nM against Trypanosoma brucei rhodesiense, the etiologic agent responsible for East African human trypanosomia...

Human African trypanosomiasis (HAT), also commonly known as sleeping sickness, is a neglected tropical disease affecting millions of people in poorly developed regions in sub-Saharan Africa. There is no satisfactory treatment for this infection. The investment necessary to bring new drugs to the market is a big deterrent to drug development, consid...

As part of our efforts to exploit the antitrypanosomal potential of sesquiterpene lactones (STL) from Helianthus tuberosus L. (Asteraceae), besides the known 4,15-iso-atriplicolide tiglate, -methacrylate and -isobutyrate, a hitherto unknown STL was isolated. Its structure was solved by extensive NMR measurements and confirmed by single crystal X-ra...

Correction for ‘The value of universally available raw NMR data for transparency, reproducibility, and integrity in natural product research’ by James B. McAlpine et al. , Nat. Prod. Rep. , 2018, DOI: 10.1039/c7np00064b.

Treatment of animal African trypanosomiasis (AAT) requires urgent need for safe, potent and affordable drugs and this has necessitated this study. We investigated the trypanocidal activities and mode of action of selected 3-aminosteroids against Trypanosoma brucei brucei. The in vitro activity of selected compounds of this series against T. congole...

Three complementary quantitative structure-activity relationship (QSAR) methodologies, namely, regression modeling based on (i) "classical" molecular descriptors, (ii) 3D pharmacophore features, and (iii) 2D molecular holograms (HQSAR) were employed on the antitrypanosomal activity of sesquiterpene lactones (STLs) toward Trypanosoma brucei rhodesie...

In continuation of a previous quantitative structure-activity relationship (QSAR) study on the antitrypanosomal activity of 69 sesquiterpene lactones (STLs) towards Trypanosoma brucei rhodesiense (Tbr) [1], the causative agent of East African form of human African trypanosomiasis, a QSAR model for a much larger and more diverse set of almost twice...

Three new tetrahydrobenzofuran-6(2H)-one-type neolignans, heterochromins A–C (1–3), along with a bicyclo[3.2.1]octane neolignan, cinerin C (4), were isolated from an ethanol extract from the leaves of Ocotea heterochroma, a native plant growing in the Colombo–Ecuadorian region of the Andes. The chemical structures of 1–3 were elucidated by spectros...

The flavoenzyme dihydroorotate dehydrogenase (DHODH) catalyzes the fourth reaction of the de novo pyrimidine biosynthetic pathway, which exerts vital functions in the cells, especially within DNA and RNA biosynthesis. Thus, this enzyme stands out as a new key molecular target for parasites causing Neglected Diseases (NDs). Focused on contributing t...

Covering: up to 2018 With contributions from the global natural product (NP) research community, and continuing the Raw Data Initiative, this review collects a comprehensive demonstration of the immense scientific value of disseminating raw nuclear magnetic resonance (NMR) data, independently of, and in parallel with, classical publishing outlets....

It has long been recognized that many sesquiterpene lactones possess very prominent anti-infective as well as antitumour potential. The structure-activity relationships underlying these as well as many other aspects of their biological activity have been reviewed extensively. Since 2006, a variety of new data have emerged that warrant an update. Th...

As part of our research for new leads against human African trypanosomiasis (HAT), we report on a 3D-QSAR study for antitrypanosomal activity and cytotoxicity of aminosteroid-type alkaloids recently isolated from the African medicinal plant Holarrhena africana A. DC. (Apocynaceae), some of which are strong trypanocides against Trypanosoma brucei rh...

As part of our research for new leads against human African trypanosomiasis (HAT), we report on a 3D-QSAR study for antitrypanosomal activity and cytotoxicity of aminosteroid-type alkaloids recently isolated from the African medicinal plant Holarrhena africana A. DC. (Apocynaceae), some of which are strong trypanocides against Trypanosoma brucei rh...

In order to determine the eutomers of potent GluN2B selective NMDA receptor antagonists with 3‐benzazepine scaffold, benzyl ethers (S)‐2 and (R)‐2 were separated by chiral HPLC. Hydrogenolysis and subsequent methylation of the enantiomerically pure benzyl ethers (S)‐2 and (R)‐2 provided the enantiomeric phenols (S)‐3 and (R)‐3 and methyl ethers (S)...

Myb is a key regulator of hematopoietic progenitor cell proliferation and differentiation and has emerged as a potential target for the treatment of acute leukemia. Using a myeloid cell line with a stably integrated Myb-inducible reporter gene as a screening tool we have previously identified Celastrol, a natural compound with anti-tumor activity,...

In the endeavor to obtain new antitrypanosomal agents, particularly sesquiterpene lactones, from Kenyan plants of the family Asteraceae, Vernonia cinerascens Sch. Bip. was investigated. Bioactivity-guided fractionation and isolation in conjunction with LC/MS-based dereplication has led to the identification of vernodalol (1) and isolation of vernod...

Natural products from plants have been used since ancestral times to treat a wide variety of diseases worldwide. Plants of the genus Salvia (Sage) have been reported to be used for the prevention and treatment of various diseases and ailments. In particular, some Salvia species have been used in traditional medicine to treat diseases caused by prot...

In search for potential therapeutic alternatives to existing treatments for cutaneous Leishmaniasis, we have investigated the effect of Arnica tincture Ph. Eur. (a 70% hydroethanolic tincture prepared from flowerheads of Arnica montana L.) on the lesions caused by infection with Leishmania braziliensis in a model with golden hamsters. The animals w...

A methanolic extract of Morella salicifolia bark was fractionated by various chromatographic techniques yielding six previously unknown cyclic diarylheptanoids, namely, 7-hydroxymyricanol 5-O-β-D-glucopyranoside (1), juglanin B 3-O-β-D-glucopyranoside (2), 16-hydroxyjuglanin B 17-O-β-D-glucopyranoside (3), myricanone 5-O-β-D-gluco-pranosyl-(1→6)-β-...

In continuation of a search for new antiprotozoal agents from plants of the family Asteraceae, Tarchonanthus camphoratus and Schkuhria pinnata have been investigated. By following the promising in vitro activity of the dichloromethane extracts from their aerial parts, bioassay-guided chromatographic isolation yielded two known sesquiterpene lactone...

In continuation of our computational efforts to find new natural inhibitors of a variety of 16 target enzymes from parasites causing neglected tropical diseases (NTDs) [1, 2], we now report on 17 the identification of 15 natural products (NPs) as inhibitors of Leishmania major Pteridine reductase 18 I (LmPTR1) by combined in silico and in vitro inv...

In our continued search for new antiprotozoal agents in plants of the family Asteraceae [1], we have investigated Schkuhria pinnata, Tarchonanthus camphoratus and Vernonia lasiopus. Bioassay-guided chromatographic fractionation and isolation from the dichloromethane extracts of the three plants led in addition to pectolinarigenin (5) and benzenepro...