Natural aristolactams and aporphine alkaloids as inhibitors of CDK1/cyclin B and DYRK1A

Predicting the Anti-SARS-CoV-2 Potential of Isoquinoline Alkaloids from Brazilian Siparunaceae Species Using Chemometric Tools

The COVID-19 pandemic has caused over 7 million deaths globally in the past four years. Siparuna spp. (Siparunaceae), which is used in Brazilian folk medicine, is considered a genus with potential antiviral alternatives. This study explored the correlation between phytochemicals in Siparuna leaf extracts (S. ficoides, S. decipiens, S. glycycarpa, S. reginae, and S. cymosa) and their potential against various SARS-CoV-2 targets. In vitro assays examined interactions between the spike protein and the ACE2 receptor, protease activity, and viral replication inhibition in Calu-3 cell models. UHPLC-MS/MS analysis, processed with MZmine and evaluated chemometrically, revealed isoquinoline alkaloids with bulbocapnine, showing promising therapeutic potential. Predictions regarding absorption, distribution, metabolism, excretion, and toxicity were conducted, along with molecular docking and dynamics simulations, to evaluate protein-ligand interaction stability. The results confirmed the antiviral activity of the Siparuna genus against SARS-CoV-2 targets, with 92% of the extracts maintaining over 70% cellular viability at 200 μg·mL-1 and 80% achieving more than 50% viral activity suppression at 50 μg·mL-1. These findings highlight the potential of isoquinoline alkaloids as novel anti-coronavirus agents and support the need for further exploration, isolation, and testing of Siparuna compounds in the fight against COVID-19.

Promotion of beta cell proliferation through DYRK kinase inhibition using the marine natural product breitfussin C

Pro-inflammatory cytokines, like interleukin-1 beta and interferon gamma, are known to activate signalling pathways causing pancreatic beta cell death and dysfunction, contributing to the onset of diabetes. Targeting cytokine signalling pathways offers a potential strategy to slow or even halt disease progression, reducing reliance on exogenous insulin and improving glucose regulation. This study explores the protective and proliferative effects of breitfussin C (BfC), a natural compound isolated from the Arctic marine hydrozoan Thuiaria breitfussi, on pancreatic beta cells exposed to pro-inflammatory cytokines. Using the beta cell line RIN-M5F, we assessed the protective effects of BfC through a MTS assay for cell viability, caspase 3/7 activity for apoptosis, and EdU incorporation and cell cycle distribution for proliferation. Additionally, we investigated BfC's inhibitory effects on the DYRK family of kinases using kinase activity and binding assays, western blotting, and docking simulations. Our findings reveal that BfC treatment effectively increases beta cell proliferation and counteracts cytokine-induced decrease in proliferation. The proliferative effect is associated with inhibition of DYRK kinases and a subsequent decrease in the cell cycle inhibitor p27KIP. These results suggest that BfC mediates beta cell-protective effect by promoting proliferation through DYRK inhibition, highlighting its potential as a molecular starting point for the development of a therapeutic agent against diabetes.

In vitro nephrotoxicity and structure-toxicity relationships of eight natural aristolactams

The structural similarity between aristolactams (ALs) and aristolochic acids (AAs) raises constant concerns about the safety of ALs-containing plants. Natural ALs are distributed more extensively than AAs, leading to a higher risk of ALs exposure in daily consumption. This study aimed to evaluate and compare the in vitro nephrotoxicity on human renal tubular epithelial cells (HK-2 cells) of eight natural ALs with different substituents on the phenanthrene ring and amide ring, including aristolactam Ⅰ (AL Ⅰ), AL BⅡ, velutinam, AL AⅡ, sauristolactam, AL AⅠa, AL FⅠ and N-methyl piperolactam A. Their IC50 values of cell viability were tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and enzyme-linked immunosorbent assay (ELISA) was used to determine the levels of kidney injury molecule-1 (KIM-1), transforming growth factor-β1 (TGF-β1) and fibronectin (FN). The reactive oxygen species (ROS) assay was used to detect the intracellular oxidative stress level. The results showed that the eight ALs all had specific nephrotoxicity on HK-2 cells. Particularly, AL Ⅰ, AL BⅡ and velutinam exhibited more potent cytotoxicity on HK-2 cells (IC50 = 2.49-2.78 μM) than the other five ALs (IC50 = 12.33-43.84 μM). The structure-toxicity relationships indicated that both methylenedioxy (-OCH2O-) and methoxy (-OCH3) were positively contributing functional groups of ALs on nephrotoxicity, while the hydroxy group (-OH) and methyl substitution on nitrogen (N-CH3) accounted for a detrimental effect conversely. Consistent with this structure-toxicity relationship, the eight ALs increased KIM-1 levels in the same trend as their cytotoxicity at the same concentration of 2.5 μg/mL, associating with different levels of ROS generation. And the four most toxic ALs, AL Ⅰ, AL BⅡ, velutinam and AL AⅡ, could also induce fibrosis by increasing TGF-β1 and FN levels.

Alkaloids from Siparuna (Siparunaceae) are predicted as the inhibitors of proteolysis and plasma coagulation caused by snake venom and potentially counteract phospholipase A2 activity of Bothrops jararaca

ETHNOPHARMACOLOGICAL RELEVANCE

Snakebite envenomation (SBE) is the world's most lethal neglected tropical disease. Bothrops jararaca is the species that causes the greatest number of SBEs in the South and Southeastern of Brazil. The main symptoms are local (inflammation, edema, hemorrhage, and myonecrosis) and systemic (hemorrhage, hemostatic alterations with consumptive coagulopathy, and death) effects. Species of the genus Siparuna, Siparunaceae, are used in folk and traditional medicine to treat SBE. However, limited information is available concerning Brazilian Siparuna species against SBE.

AIM OF THE STUDY

To investigate the correlation between the compounds present in the extracts of five Siparuna species as potential agents against proteolytic activity, plasma coagulation, and phospholipase A2 (PLA2) activity caused by B. jararaca venom, using data obtained by UHPLC-MS/MS, biological activity, and multivariate statistics.

MATERIALS AND METHODS

The ethanol extracts from leaves of S. ficoides, S. decipiens, S. glycycarpa, S. reginae, and S. cymosa were fractionated by liquid-liquid extraction using different solvents of increasing polarity (hexane, dichloromethane, ethyl acetate, and n-butanol), affording their respective extracts, totaling 25 samples that were assayed through in vitro plasma coagulation and proteolytic activity assays. Moreover, the extracts were analyzed by UHPLC-MS/MS, using electrospray ionization (ESI) and atmospheric-pressure chemical ionization (APCI) in negative and positive ionization modes. The data was processed in MZmine v. 2.53 and evaluated by multivariate statistical tests (PLS) using the software UnscramblerX v. 10.4. These data were also used to build molecular networks (GNPS), and some ions of interest could be annotated using the library of molecules on the GNPS platform.

RESULTS

A total of 19 extracts inhibited B. jararaca-induced plasma coagulation, with emphasis on S. cymosa and S. reginae (800 s). The inhibition of the proteolytic activity was also promising, ranging from 16% (S. glycycarpa) to 99% (S. cymosa, S. decipiens, and S. reginae). In addition, most extracts from S. cymosa and S. reginae inhibited 70-90% of PLA2 activity. Based on data from positive mode APCI analyses, it was possible to obtain a statistic model with reliable predictive capacity which exhibited an average R2 of 0.95 and a Q2 of 0.88, indicating a robust fit. This process revealed five ions, identified as the alkaloids: coclaurine (1), stepholidine (2) O-methylisopiline (3), nornantenine (4) and laurolitsine (5). This is the first study to evidence the potential antivenom of alkaloids from Siparuna species.

CONCLUSIONS

Altogether, our results give support to the popular use of Siparuna extracts in SBE accidents, suggesting their potential as an alternative or complementary strategy against envenoming by B. jararaca venom. The predicted ions in the chemometric analysis for the assayed activities can also be correlated with the blocking activity and encourage the continuation of this study for possible isolation and testing of individual compounds on the used models.

A deconstruction-reconstruction strategy to access 1-naphthol derivatives: application to the synthesis of aristolactam scaffolds

A deconstruction-reconstruction strategy for the synthesis of multisubstituted polycyclic aromatic hydrocarbons (PAHs) is delineated herein. The deconstruction step enables the synthesis of o-cyanomethylaroyl fluorides that are bifunctional substrates holding both a pro-nucleophile and an electrophile. The construction step involves a formal [4 + 2] benzannulation using o-cyanomethylaroyl fluorides and active methylenes. The utility of this synthetic method is also demonstrated by the synthesis of a tetracyclic aristolactam derivative.

Comparative Efficacy and Selectivity of Pharmacological Inhibitors of DYRK and CLK Protein Kinases

Dual-specificity, tyrosine phosphorylation-regulated kinases (DYRKs) and cdc2-like kinases (CLKs) play a large variety of cellular functions and are involved in several diseases (cognitive disorders, diabetes, cancers, etc.). There is, thus, growing interest in pharmacological inhibitors as chemical probes and potential drug candidates. This study presents an unbiased evaluation of the kinase inhibitory activity of a library of 56 reported DYRK/CLK inhibitors on the basis of comparative, side-by-side, catalytic activity assays on a panel of 12 recombinant human kinases, enzyme kinetics (residence time and K_d), in-cell inhibition of Thr-212-Tau phosphorylation, and cytotoxicity. The 26 most active inhibitors were modeled in the crystal structure of DYRK1A. The results show a rather large diversity of potencies and selectivities among the reported inhibitors and emphasize the difficulties to avoid "off-targets" in this area of the kinome. The use of a panel of DYRKs/CLKs inhibitors is suggested to analyze the functions of these kinases in cellular processes.

Non-volatile constituents from Monimiaceae, Siparunaceae and Atherospermataceae plant species and their bioactivities: An up-date covering 2000-2021

The Monimiaceae, Siparunaceae, and Atherospermataceae, formerly included in the broad ''old'' Monimiaceae family, have long been known for their uses in traditional medicine and have proven to be rich sources of chemically diverse specialized metabolites with numerous potent biological and therapeutical properties. The progress made recently has expanded their phytochemistry and pharmacology albeit to different extents. This review focuses on the non-volatile constituents isolated from the three plant families during the last two decades and their emerging therapeutic potential. Based on the data collected from multiple databases without statistical analysis, approximately 93 components, of which 35 undescribed compounds including γ-lactones, alkaloids, terpenoids, flavonoids, and homogentisic acid derivatives, have been reported. Moreover, diverse biological activities of pure isolated compounds such as anticancer, antioxidant, antiparasitic, antiviral, and antibacterial activities have been evidenced. Besides offering new important perspectives for different diseases' management, the chemical and biological diversities among the isolated compounds, open promising avenues of research and contribute to renewed interest in these families needing further studies. This review provides an updated overview of their potential as sources of leads for drug discovery, while also highlighting ongoing challenges and future research opportunities.

Diabetic Kinome Inhibitors-A New Opportunity for β-Cells Restoration

Diabetes, and several diseases related to diabetes, including cancer, cardiovascular diseases and neurological disorders, represent one of the major ongoing threats to human life, becoming a true pandemic of the 21st century. Current treatment strategies for diabetes mainly involve promoting β-cell differentiation, and one of the most widely studied targets for β-cell regeneration is DYRK1A kinase, a member of the DYRK family. DYRK1A has been characterized as a key regulator of cell growth, differentiation, and signal transduction in various organisms, while further roles and substrates are the subjects of extensive investigation. The targets of interest in this review are implicated in the regulation of β-cells through DYRK1A inhibition-through driving their transition from highly inefficient and death-prone populations into efficient and sufficient precursors of islet regeneration. Increasing evidence for the role of DYRK1A in diabetes progression and β-cell proliferation expands the potential for pharmaceutical applications of DYRK1A inhibitors. The variety of new compounds and binding modes, determined by crystal structure and in vitro studies, may lead to new strategies for diabetes treatment. This review provides recent insights into the initial self-activation of DYRK1A by tyrosine autophosphorylation. Moreover, the importance of developing novel DYRK1A inhibitors and their implications for the treatment of diabetes are thoroughly discussed. The evolving understanding of DYRK kinase structure and function and emerging high-throughput screening technologies have been described. As a final point of this work, we intend to promote the term "diabetic kinome" as part of scientific terminology to emphasize the role of the synergistic action of multiple kinases in governing the molecular processes that underlie this particular group of diseases.

Plant Extracts and their Secondary Metabolites as Modulators of Kinases

Natural Products (NP), specifically from medicinal plants or herbs, have been extensively utilized to analyze the fundamental mechanisms of ultimate natural sciences as well as therapeutics. Isolation of secondary metabolites from these sources and their respective biological properties, along with their lower toxicities and cost-effectiveness, make them a significant research focus for drug discovery. In recent times, there has been a considerable focus on isolating new chemical entities from natural flora to meet the immense demand for kinase modulators, and also to overcome major unmet medical challenges in relation to signal transduction pathways. The signal transduction systems are amongst the foremost pathways involved in the maintenance of life and protein kinases play an imperative part in these signaling pathways. It is important to find a kinase inhibitor, as it can be used not only to study cell biology but can also be used as a drug candidate for cancer and metabolic disorders. A number of plant extracts and their isolated secondary metabolites such as flavonoids, phenolics, terpenoids, and alkaloids have exhibited activities against various kinases. In the current review, we have presented a brief overview of some important classes of plant secondary metabolites as kinase modulators. Moreover, a number of phytocompounds with kinase inhibition potential, isolated from different plant species, are also discussed.

A Serendipitous One-Pot Cyanation/Hydrolysis/Enamide Formation: Direct Access to 3-Methyleneisoindolin-1-ones

A direct, one-pot conversion of 2'-haloacetophenones to 3-methyleneisoindolin-1-one scaffolds using CuCN as the sole reagent without the need for moisture-free or anaerobic conditions is reported. This serendipitously discovered transformation with a broad substrate scope provides a significantly different route towards these important scaffolds. The scope of the method has also been further extended towards the synthesis of three special scaffolds, which are analogous to various bio-active drugs.

1-Isoindolinone scaffold-based natural products with a promising diverse bioactivity

Isoindolin-1-one or 1-isoindolinone framework is referred to phthalimidines or benzo fused γ-lactams of the corresponding γ-amino carboxylic acids and has been of prime interest for scientists for last several decades. 1-Isoindolinone framework is found in a wide range of naturally occurring compounds with diverse biological activities and therapeutic potential for various chronic diseases. Recent developments in synthetic methods for their procurement have opened a new era of 1-isoindolinone chemistry. This review aims to provide an alphabetical quick reference guide to only 1-isoindolinone based natural products and its variable fused, oxidized and reduced state skeleton with information for advanced chemotaxonomic analyses, cellular targets/pathways and diverse biological activities and future use for medicinal chemistry.

DYRK1A kinase inhibition with emphasis on neurodegeneration: A comprehensive evolution story-cum-perspective

Alzheimer, the fourth leading cause of death embodies a key responsible event including formation of β-amyloid protein clustering to amyloid plaque on blood vessels. The origin of above events is Amyloid precursor protein (APP) which is an integral membrane protein known for its function in synapses formation. Modern research had proposed that the over expression of DYRK1A (Dual specificity tyrosine phosphorylation regulated kinase1A, a family of protein kinases, positioned within the Down's syndrome critical region (DSCR) on human chromosome 21causes phosphorylation of APP protein resulting in its cleavage to Aβ 40, 42 and tau proteins (regulated by beta and gamma secretase) which plays critical role in early onset of Alzheimer's disease (AD) detected in Down's syndrome (DS), leading to permanent functional and structural deformities which results ultimately into neuro-degeneration and neuronal death. Therefore, DYRK1A emerges as a potential target for prevention of neuro-degeneration and hence Alzheimer. Presently, the treatment methods for Down's syndrome, as well as Alzheimer's disease are extremely biased and represent a major deficiency for therapeutic necessities. We hereby, focus our review on the current status of the research and contributions in the development of DYRK1A inhibitors.

Culture-Bound Syndromes of a Brazilian Amazon Riverine population: Tentative correspondence between traditional and conventional medicine terms and possible ethnopharmacological implications

ETHNOPHARMACOLOGICAL RELEVANCE

It is not always possible to correlate the "emic" terms to the "etic" ones during ethnopharmacological surveys, especially regarding those related to Culture-Bound Syndromes (CBS). Nevertheless, it is the role of ethnopharmacology to address these correlations, since they are the basis for the understanding of potential bioactives.

AIM AND OBJECTIVES

This study reports the clinical manifestations and therapeutic resources used for the treatment of CBS among some riverine inhabitants of Brazilian Amazonia. An effort was made to establish a correspondence between the local "emic" terms of traditional medicine and the symptoms or diseases known by conventional medicine ("etic" terms). The ultimate goal was to gain insights to suggest further pharmacological studies with the local resources.

MATERIAL AND METHODS

Fieldwork was guided by methods of anthropology, botany and zoology-with the assistance of a doctor-among the traditional healing experts in Jaú National Park (during 199 days in 1995) and Unini River Extractive Reserve (210 days from 2008 to 2012).

RESULTS

Fifty-nine healers of different kinds were interviewed: a prayer-maker, medium, natural resource expert, massage therapist, midwife and snakebite healer. The clinical manifestations and healing resources of the following CBS were collected: "mau olhado" (evil eye), "quebrante" (chipping); "espante" (fright or susto); "doença do ar" (air diseases); "vento caído" (fallen wind); "derrame" (leakage); "mãe do corpo" (mother of the body) and "panema" (unlucky). The first three seem to be local variations of other CBSs already described in Latin America. "doença do ar", "vento caído", "derrame" and "mãe do corpo" seem to be folk terms for known conventional medical disorders, while "panema" is a yet undescribed Brazilian CBS that is possibly related to dysthymic disorder or depression and deserves further investigation. Treatments included prayer rituals, fumigation, baths and oral remedies using 25 plants and 10 animals.

CONCLUSION

It was possible to establish hypothetical correlations between CBS as described by the riverine population studied and some "etic" terms. The main importance of this is to help the proposition of target-oriented pharmacological studies of the natural resources used by these communities. Accordingly, the following plants are suggested to be submitted to further studies for antidepressant and anxiolytic activities: Siparuna guianensis, Mansoa alliacea, Leucas martinicensis, Petiveria alliacea, Annona montana and Alpinia nutans; for anti-seizure activity: Protium amazonicum, Protium aracouchini and Protium heptaphyllum; finally for antispasmodic activity: Leucas martinicensis.

Cytotoxic cardenolides and sesquiterpenoids from the fruits of Reevesia formosana

Bioassay-guided fractionation of the fruits of Reevesia formosana led to isolation of three cardenolides (reevesioside J, reevesioside K, and epi-reevesioside K), three sesquiterpenoids (reevesiterpenol C, reevesiterpenol D, and reevesiterpenol E), and two glycosides (reevesianin A and reevesianin B), along with 46 known compounds. Their structures were determined using spectroscopic techniques. In addition to the reported cytotoxic cardenolides, reevesioside J and strophanthidin exhibited moderate cytotoxicity against the cell lines MCF-7, NCI-H460, and HepG2, with IC50 values of 0.39 ± 0.06 μM and 1.06 ± 0.12 μM for MCF-7, 0.12 ± 0.01 μM and 0.29 ± 0.01 μM for NCI-H460, and 1.09 ± 0.02 μM and 1.72 ± 0.02 μM for HepG2, respectively. Reevesiterpenol E also exhibited the best selective cytotoxicity to the NCI-H460 cell line, with an IC50 value of 3.15 ± 0.22 μM.

New Caledonia: A ' Hot Spot' for Valuable Chemodiversity: Part 2: Basal Angiosperms and Eudicot Rosids

The flora of New Caledonia encompasses more than 3000 plant species and almost 80% are endemic. New Caledonia is considered as a 'hot spot' for biodiversity. With the current global loss of biodiversity and the fact that several drugs and pesticides become obsolete, there is an urgent need to increase sampling and research on new natural products. In this context, we review the chemical knowledge available on New Caledonian native flora from economical perspectives. We expect that a better knowledge of the economic potential of plant chemistry will encourage the plantation of native plants for the development of a sustainable economy which will participate in the conservation of biodiversity. In the second part of this review, we focus on the results exposed in 60 scientific articles and describe the identification of 225 original compounds from basal angiosperms and eudicot rosids. We discuss the economic potential of plants and molecules from medicinal and industrial perspectives. This review also highlights several plants and groups, such as Amborella sp., Piperaceae, or Phyllanthaceae, that are unexplored in New Caledonia despite their high chemical interest. Those plants are considered to have priority in future chemical investigations.

Acridone alkaloids from Glycosmis chlorosperma as DYRK1A inhibitors

Two new acridone alkaloids, chlorospermines A and B (1 and 2), were isolated from the stem bark of Glycosmis chlorosperma, together with the known atalaphyllidine (3) and acrifoline (4), by means of bioguided isolation using an in vitro enzyme assay against DYRK1A. Acrifoline (4) and to a lesser extent chlorospermine B (2) and atalaphyllidine (3) showed significant inhibiting activity on DYRK1A with IC50's of 0.075, 5.7, and 2.2 μM, respectively. Their selectivity profile was evaluated against a panel of various kinases, and molecular docking calculations provided structural details for the interaction between these compounds and DYRK1A.

The uniqueness and therapeutic value of natural products from West African medicinal plants. Part I: uniqueness and chemotaxonomy

This review gives an in depth coverage of the natural products derived from West African medicinal plants with diverse biological activities.

The chemistry of isoindole natural products

This review highlights the chemical and biological aspects of natural products containing an oxidized or reduced isoindole skeleton. This motif is found in its intact or modified form in indolocarbazoles, macrocyclic polyketides (cytochalasan alkaloids), the aporhoeadane alkaloids, meroterpenoids from Stachybotrys species and anthraquinone-type alkaloids. Concerning their biological activity, molecular structure and synthesis, we have limited this review to the most inspiring examples. Within different congeners, we have selected a few members and discussed the synthetic routes in more detail. The putative biosynthetic pathways of the presented isoindole alkaloids are described as well.