Dihydrofolate reductase and cell growth activity inhibition by the beta-carboline-benzoquinolizidine plant alkaloid deoxytubulosine from Alangium lamarckii: its potential as an antimicrobial and anticancer agent

Functional network analysis identifies multiple virulence and antibiotic resistance targets in Stenotrophomonas maltophilia

Stenotrophomonas maltophilia, an emerging multidrug-resistant opportunistic bacterium in humans is of major concern for immunocompromised individuals for causing pneumonia and bloodborne infections. This bacterial pathogen is associated with a considerable fatality/case ratio, with up to 100%, when presented as hemorrhagic fever. It is resistant to commonly used drugs as well as to antibiotic combinations. In-silico based functional network analysis is a key approach to get novel insights into virulence and resistance in pathogenic organisms. This study included the protein-protein interaction (PPI) network analysis of 150 specific genes identified for antibiotic resistance mechanism and virulence pathways. Eight proteins, namely, PilL, FliA, Smlt2260, Smlt2267, CheW, Smlt2318, CheZ, and FliM were identified as hub proteins. Further docking studies of 58 selected phytochemicals were performed against the identified hub proteins. Deoxytubulosine and corosolic acid were found to be potent inhibitors of hub proteins of pathogenic S. maltophilia based on protein-ligand interactive study. Further pharmacophore studies are warranted with these molecules to develop them as novel antibiotics against S. maltophilia.

A computational chemistry-driven hypothesis on the mode of action of Hipposudoric Acid and related analogs

Aim: To elucidate the mode of action of the hipposudoric acid derivatives and identify hit compounds for synthesis. Materials & methods: Structural fragments of known bioactive fluorenes were introduced onto the hipposudoric acid scaffold to yield novel derivatives. The binding motifs of the novel compounds were compared to the pharmacophore of DHFR co-crystallized with Methotrexate (MTX). Results: Several of the novel compounds showed binding affinities that exceeded the affinity of the docked endogenous ligand (dihydrofolic acid). Conclusion: This study indicates that compounds 3r₁₂, 3r₉, 1s₉ and 3r₁₀ are promising candidates for synthesis and pharmacological evaluation.

Bioassay-Guided Fractionation, ESI-MS Scan, Phytochemical Screening, and Antiplasmodial Activity of Afzelia africana

Background. Afzelia africana is a plant species with reported numerous medicinal potentials and secondary metabolites. Various parts of the plant have been applied for the treatment of hernia, rheumatism, pain, lumbago, malaria, etc. The study seeks to evaluate the phytochemical constituents, antiplasmodial, and ESI-MS scan of bioassay-guided fractions from the methanol extract of the bark of the plant. Aims. The main aim of the study was to carry out bioassay-guided fractionation of the crude methanol extract of Afzelia africana in order to isolate fractions and to evaluate their antiplasmodial activities and ESI-MS fingerprints. Methods. The methods employed include column chromatographic fractionation, phytochemical screening, antiplasmodial activity (malaria SYBER green assay (MSF)), and ESI-MS profile (full ESI-MS scan). Results. The column chromatographic fractionation and phytochemical screening of the plant led to the separation of the following four fractions: 1 (flavonoids, phenolics, glycosides, terpenoids, and steroids), 2 (alkaloids, anthraquinones, flavonoids, phenolics, glycosides, terpenoids, and steroids), 3 (anthraquinones, flavonoids, phenolics, glycosides, terpenoids, and steroids), and 4 (alkaloids, flavonoids, phenolics, glycosides, terpenoids, and steroids). The antiplasmodial activities of the fractions were tested against the 3D7 strain of Plasmodium falciparum with reported stronger activities for 1 (IC50: 0.097 ± 0.034 μg/mL) and 3 (IC50: 1.43 ± 0.072 μg/mL), and weaker activities for 2 (IC50: >100 μg/mL) and 4 (IC50: 37.09 ± 6.14 μg/mL). The full ESI-MS fingerprint of fractions 1, 2, 3, and 4 revealed the presence of 14, 24, 34, and 37 major molecular ions or compounds in each fraction, respectively.

Arylation of enelactams using TIPSOTf: reaction scope and mechanistic insight

Triisopropylsilyltrifluoromethanesulfonate can be effectively used for the arylation of a wide range of enelactams. The multinuclear NMR study provided deep insights into the reaction mechanism.

Genus Alangium - A review on its traditional uses, phytochemistry and pharmacological activities

The species from Alangium have been used as folk medicine to treat rheumatism, skin diseases, diabetes by the people of Southeast Asia. Previous phytochemical studies have shown this genus are rich sources of alkaloids, glycosides, and terpenoids, which have attracted considerable attention of many researchers due to their markedly diverse and complex architecture. The crude extracts as well as the monomeric compounds from the title genus possess anti-tumor, anti-inflammatory, antibacterial, anti-oxidant pharmacological activities. Besides, some isolates from Alangium exhibited the effects on skeletal, smooth muscle and the nervous system. As a large genus of medicinal plants, the medicinal value of Alangium has been widely reported, but there is no review that provide a systematic summary towards its chemical constituents and pharmacological activities, to our knowledge. This work aims to present a comprehensive overview on the traditional uses, phytochemistry, and pharmacological activities of medicinal plants in the genus Alangium, and to explore the evidence supporting its ethnopharmacological effectiveness.

Bioactive fluorenes. Part III: 2,7-dichloro-9H-fluorene-based thiazolidinone and azetidinone analogues as anticancer and antimicrobial against multidrug resistant strains agents

Background

Thiazoles, thiazolidinones and azetidinones are highly ranked amongst natural and synthetic heterocyclic derivatives due to their great pharmaceutical potential.

Results

New thiazolidinone and azetidinone class of bioactive agents based on 4-(2,7-dichloro-9H-fluoren-4-yl)thiazole moiety have been successfully synthesized. 4-(2,7-dichloro-9H-fluoren-4-yl)thiazol-2-amine was synthesized and allowed to react with various aryl/heteroaryl aldehydes to afford the corresponding Schiff base intermediates. The target thiazolidinone and azetidinone analogues have derived from Schiff bases by their reactions with thioglycolic acid and chloroacetyl chloride, respectively. The newly synthesized compounds were then evaluated for their antimicrobial activity against some multidrug resistant strains and examined for cytotoxic activity against normal lung fibroblast (WI-38), human lung carcinoma (A549), and human breast carcinoma (MDA-MB-231) cell lines to develop a novel class of fluorene-based bioactive agents. The mode of action and the binding interaction of the synthesized compound with the active sites of dihydrofolate reductase enzyme were well identified by fluorescence-activated cell sorting (FACS) analysis and molecular docking study.

Conclusion

Some of the synthesized compounds showed remarkable activity against A-549 and MDA-MB-231 when compared to Taxol, which was used as a reference drug. 2,7-dichloro-9H-fluorene-based azetidinones are more efficient as antimicrobial and anticancer agents compared to dichloro-9H-fluorene-based thiazolidinones derivatives.

A Grand Challenge. 3. Unbiased Phenotypic Function of Metabolites from Australia Plants Gloriosa superba and Alangium villosum against Parkinson's Disease

As part of a continuing research program aiming to identify chemical probes to interrogate Parkinson's disease (PD), we have investigated the Australian plants Gloriosa superba and Alangium villosum. The chemical investigations of G. superba resulted in the isolation of four new alkaloids, β-lumicolchicosides A-C (1-3) and γ-lumicolchicoside A (4), together with four lumicolchicine derivatives (5-8) and six colchicine analogues (9-14) as known structures. The chemical investigations of A. villosum resulted in the isolation of four new benzoquinolizidine N-oxides, tubulosine N_β⁵-oxide (15), isotubulosine N_α⁵-oxide (16), 9-demethyltubulosine N_β⁵-oxide (17), and 9-demethylisotubulosine N_α⁵-oxide (18), together with five known benzoquinolizidine alkaloids (19-23). The chemical structures of the new compounds (1-4 and 15-18) were characterized unambiguously by extensive analysis of their NMR and MS data. Unbiased multidimensional profiling was used to investigate the phenotypic profiles of all of the metabolites. The results show that the lead probes have different effects on cellular organelles that are implicated in PD in patient-derived cells.

Bioactive fluorenes. part I. Synthesis, pharmacological study and molecular docking of novel dihydrofolate reductase inhibitors based-2,7-dichlorofluorene

In this study, a new series of 2,7-dichloro-4-(2-substituted-amino acetyl)fluorene derivatives were synthesized, characterized and evaluated for their antimicrobial activity and screened for cytotoxic activity against human lung carcinoma (A-549) and human breast carcinoma (MCF-7) cell lines. Most of the synthesized compounds displayed significant activity against A-549 and MCF-7 cell lines when compared to 5-fluorouracil (5-FU), which was used as a reference drug. In addition, some of these reported novel compounds exhibited promising antibacterial and antifungal properties. A molecular docking study was performed to identify the mechanism of action of the synthesized compounds, which suggested binding interactions with the active sites of dihydrofolate reductase (DHFR).

Design, synthesis, and biological evaluation of novel N 4 -substituted sulfonamides: acetamides derivatives as dihydrofolate reductase (DHFR) inhibitors

Background

Sulfonamide derivatives are of great attention due to their wide spectrum of biological activities. Sulfonamides conjugated with acetamide fragments exhibit antimicrobial and anticancer activities. The inhibition dihydrofolate reductase (DHFR) is considered as one of the most prominent mechanism though which sulfonamide derivatives exhibits antimicrobial and antitumor activities.

Results

In this study, a new series of 2-(arylamino)acetamides and N-arylacetamides containing sulfonamide moieties were designed, synthesized, characterized and assessed for their antimicrobial activity and screened for cytotoxic activity against human lung carcinoma (A-549) and human breast carcinoma (MCF-7) cell lines. A molecular docking study was performed to identify the mode of action of the synthesized compounds and their good binding interactions were observed with the active sites of dihydrofolate reductase (DHFR).

Conclusion

Most of the synthesized compounds showed significant activity against A-549 and MCF-7 when compared to 5-Fluorouracil (5-FU), which was used as a reference drug. Some of these synthesized compounds are active as antibacterial and antifungal agents.

Electronic supplementary material

The online version of this article (10.1186/s13065-019-0603-x) contains supplementary material, which is available to authorized users.

Alkaloids for cancer prevention and therapy: Current progress and future perspectives

Alkaloids are important chemical compounds that serve as a rich source for drug discovery. Numerous alkaloids screened from medicinal plants and herbs showed antiproliferative and anticancer effects on wide category of cancers both in vitro and in vivo. Vinblastine, vinorelbine, vincristine, and vindesine have already been successfully developed as anticancer drugs. The available and up-to-date information on the ethnopharmacological uses in traditional medicine, phytochemistry, pharmacology and clinical utility of alkaloids were collected using various resources (PubMed, ScienceDirect, Google Scholar and Springerlink). In this article, we provide a comprehensive and critical overview on naturally-occurring alkaloids with anticancer activities and highlight the molecular mechanisms of action of these secondary metabolites. Furthermore, this review also presents a summary of synthetic derivatives and pharmacological profiles useful to researchers for the therapeutic development of alkaloids. Based on the literature survey compiled in this review, alkaloids represent an important group of anticancer drugs of plant origin with enormous potential for future development of drugs for cancer therapy and management.

6-OH-Phenanthroquinolizidine Alkaloid and Its Derivatives Exert Potent Anticancer Activity by Delaying S Phase Progression

To discover new phenanthroindolizidine and phenanthroquinolizidine alkaloids as potential anticancer drug candidates, non-natural 6-O-desmethylcryptopleurine (2) and its derivatives were prepared. Most of the new compounds exhibited potent antiproliferative activity against A549 and BEL-7402 cells, with the lowest IC₅₀ being 3 nM. Optically pure 2-R was further evaluated against a panel of 30 cancer cell lines and found to inhibit the proliferation of all tested cell lines, including three multidrug-resistant cell lines, with an average IC₅₀ value of 2.1 nM, which is much lower than that of previously reported phenanthroindolizidine DCB-3503 (1, IC₅₀: 166.7 nM). A mechanistic evaluation showed that 2-R potently inhibited cell growth and colony formation, which are associated with a delay in S phase progression through the inhibition of DNA synthesis. These results along with further study on the safety profile of these compounds will facilitate the discovery of new phenanthroindolizidine and phenanthroquinolizidine alkaloids for use as anticancer drug candidates.

Study of reactivity of cyanoacetohydrazonoethyl-N-ethyl-N-methyl benzenesulfonamide: preparation of novel anticancer and antimicrobial active heterocyclic benzenesulfonamide derivatives and their molecular docking against dihydrofolate reductase

This article describes the synthesis of some novel heterocyclic sulfonamides having biologically active thiophene 3, 4, 5, 6, coumarin 8, benzocoumarin 9, thiazole 7, piperidine 10, pyrrolidine 11, pyrazole 14 and pyridine 12, 13. Starting with 4-(1-(2-(2-cyanoacetyl)hydrazono)ethyl)-N-ethyl-N-methylbenzenesulfonamide (2), which was prepared from condensation of acetophenone derivative 1 with 2-cyanoacetohydrazide. The structures of the newly synthesized compounds were confirmed by elemental analysis, IR, ¹H NMR, ¹³C NMR, ¹⁹F NMR and MS spectral data. All the newly synthesized heterocyclic sulfonamides were evaluated as in-vitro anti-breast cancer cell line (MCF7) and as in-vitro antimicrobial agents. Compounds 8, 5 and 11 were more active than MTX reference drug and compounds 12, 7, 4, 14, 5 and 8 were highly potent against Klebsiella pneumonia. Molecular operating environment performed virtual screening using molecular docking studies of the synthesized compounds. The results indicated that some prepared compounds are suitable inhibitor against dihydrofolate reductase (DHFR) enzyme (PDBSD:4DFR) with further modification.

Novel Benzo[a]quinolizidine Analogs Induce Cancer Cell Death through Paraptosis and Apoptosis

Paraptosis is nonapoptotic cell death characterized by massive endoplasmic reticulum (ER)- or mitochondria-derived vacuoles. Induction of paraptosis offers significant advantages for the treatment of chemotherapy-resistant tumors compared with anticancer drugs that rely on apoptosis. Because some natural alkaloids induce paraptotic cell death, a novel series of benzo[a]quinolizidine derivatives were synthesized, and their antiproliferative activity and ability to induce cytoplasmic vacuolation were analyzed. Structural optimization led to the identification of the potent compound 22b, which inhibited cancer cell proliferation in vitro and in vivo and profoundly facilitated paraptosis-like cell death and induced caspase-dependent apoptosis. Further investigation revealed that 22b-mediated vacuolation originated from persistent ER stress and upregulation of LC3B. Paraptosis induced by benzo[a]quinolizidine derivatives thus represents an alternative strategy for cancer chemotherapy.

Synthesis, spectroscopic properties, molecular docking, anti-colon cancer and anti-microbial studies of some novel metal complexes for 2-amino-4-phenylthiazole derivative

This article describes the synthesis of novel bidentate Schiff base (H2L) from condensation of 2-amino-4-phenylthiazole (APT) with 4,6-diacetylresorcinol (DAR) in the molar ratio 2:1. We studied interaction of ligand (H2L) with transition metal ions such as Cr(III), Fe(III), Cu(II), Zn(II) and Cd(II). The ligand (H2L) has two bidentate sets of (N-O) units which can coordinate with two metal ions to afford novel binuclear metal complexes. The directions of coordinate bonds are from nitrogen atoms of azomethine groups and oxygen atoms of the phenolic groups. Structures of the newly synthesized complexes were confirmed by elemental analysis, IR, UV, (1)H NMR, ESR, TGA and mass spectral data. All of the newly synthesized complexes were evaluated for their antibacterial and anti-fungal activities. They were also evaluated for their in vitro anticancer activity against human colon carcinoma cells (HCT-116) and mammalian cells of African green monkey kidney (VERO). The Cu(II) complex with selectivity index (S.I.)=21.26 exhibited better activity than methotrexate (MTX) as a reference drug with S.I. value=13.30, while Zn(II) complex with S.I. value=10.24 was found to be nearly as active as MTX. Molecular docking studies further helped in understanding the mode of action of the compounds through their various interactions with active sites of dihydrofolate reductase (DHFR) enzyme. The observed activity of Fe(III) and Cu(II) complexes gave rise to the conclusion that they might exert their action through inhibition of the DHFR enzyme.

GLABROUS INFLORESCENCE STEMS regulates trichome branching by genetically interacting with SIM in Arabidopsis

Arabidopsis trichomes are large branched single cells that protrude from the epidermis. The first morphological indication of trichome development is an increase in nuclear content resulting from an initial cycle of endoreduplication. Our previous study has shown that the C2H2 zinc finger protein GLABROUS INFLORESCENCE STEMS (GIS) is required for trichome initiation in the inflorescence organ and for trichome branching in response to gibberellic acid signaling, although GIS gene does not play a direct role in regulating trichome cell division. Here, we describe a novel role of GIS, controlling trichome cell division indirectly by interacting genetically with a key endoreduplication regulator SIAMESE (SIM). Our molecular and genetic studies have shown that GIS might indireclty control cell division and trichome branching by acting downstream of SIM. A loss of function mutation of SIM signficantly reduced the expression of GIS. Futhermore, the overexpression of GIS rescued the trichome cluster cell phenotypes of sim mutant. The gain or loss of function of GIS had no significant effect on the expression of SIM. These results suggest that GIS may play an indirect role in regulating trichome cell division by genetically interacting with SIM.

Identification of an anti-MRSA dihydrofolate reductase inhibitor from a diversity-oriented synthesis

The screening of a diversity-oriented synthesis library followed by structure-activity relationship investigations have led to the discovery of an anti-MRSA agent which operates as an inhibitor of Staphylococcus aureus dihydrofolate reductase.

Cytotoxic Alangium alkaloids from Alangium longiflorum

Seven alkaloids (1-7) were isolated from the stem bark of Alangium longiflorum. Compound 1, (-)-10-O-demethylisocephaeline, was isolated for the first time as a naturally occurring product from a plant source. All structures were elucidated by detailed spectroscopic analysis. Biological evaluation showed that 2, 10-O-demethylcephaeline, exhibited potent cytotoxic activity against human lung carcinoma (A549) and breast adenocarcinoma (MCF-7) with ED(50) values of 0.013 and 0.062 microM, respectively. The stereoisomer 1 was less potent than 2, and related compounds with different hydroxy/methoxy substitution patterns were also less potent or inactive. Thus, compound 2 merits attention as a cytotoxic lead for further study.

The biosynthesis of beta-carboline and quinolizidine alkaloids of Alangium lamarckii

The incorporation of tryptamine, dopamine, N-deacetylisoipecoside, N-deacetylipecoside into alangimarckine, deoxytubulosine and ankorine and of strictosidine and vincoside into alangimarckine and deoxytubulosine in young Alangium lamarckii Thw. (Alangiaceae) has been studied and specific utilisation of N-deacetylisoipecoside demonstrated. Parallel experiments with nordeoxytubulosine and deoxytubulosine suggested that O-methylation precedes condensation of protoemetine with tryptamine and further the reduction of ethylene side chain takes place before condensation. Hydroxylation at C-8 in the trans-quinolizidine moiety is the terminal step in the biosynthesis of alangimarckine.