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Ethnobotanical Relevance: For centuries, the aerial parts of Sideritis species have been known for their medicinal properties as herbal teas. Although the antioxidant and anti-inflammatory properties of the genus have been widely documented, the underlying mechanisms are yet to be sufficiently clarified., Aim of the Study: We investigated the anti-inflammatory and anticancer activities of phytochemicals of the Sideritis genus., Material and Methods: Through literature mining, a chemical library containing 657 components of the Sideritis genus was formed. We studied these compounds for binding to NLRP3 and NF-κB proteins in silico by virtual drug screening and molecular docking, and in vitro by microscale thermophoresis (MST). Liquid chromatography-high-resolution mass spectrometry analysis (LC-HRMS) was performed in the Sideritis extracts. One of the identified compounds, verbascoside, was investigated for its cytotoxic activity by mining a panel of 49 tumor cell lines in the data repository of the National Cancer Institute (NCI, USA)., Results: Virtual screening and molecular docking results highlighted two compounds targeting both proteins of interest, i.e., verbascoside (acteoside) and apigenin 7,4'-bis(trans-p-coumarate), as both had lowest binding energies of less than -10 kcal/mol. Using MST, we then verified that both compounds bound to the target proteins. Verbascoside bound to NLRP3 and NF-κB with K d values of 0.67 ± 0.18 μM and 0.01 ± 0.08 μM, while apigenin 7,4'-bis(trans-p-coumarate) had K d values of 4.60 ± 1.66 μM and 0.27 ± 0.75 μM, respectively. Verbascoside was abundant in the Sideritis extracts, according to LC-HRMS analysis. Since inflammation is strongly related to carcinogenesis, we investigated the anticancer activity of verbascoside in the second part of this study. We investigated the activity of verbascoside in 49 tumor cell lines of the NCI. Comparing its activity with 81 standard anticancer drugs revealed numerous interactions with DNA-damaging agents (alkylators, topoisomerase I/II inhibitors, antimetabolites), indicating that verbascoside may also affect the DNA of tumor cells. We further investigated the involvement of verbascoside in several main drug resistance mechanisms, i.e., ABC transporters, oncogenes, tumor suppressors, cellular proliferation rates, and other parameters. Except for the correlation to the mutational status of NRAS, no other significant relationships were found, indicating that verbascoside is not involved in most of the common drug resistance mechanisms. Two-dimensional cluster analysis-based heatmap generation of a proteomic profile from 40 out of 3171 proteins revealed a significant correlation between the expression of these proteins in 49 tumor cell lines, and the cellular response to verbascoside. This indicates that the presence of these proteins is a determinant for sensitivity or resistance to this natural product., Conclusion: The database established here represents a valuable resource for the screening of bioactivites of the Sideritis genus. The experimental validation of the anti-inflammatory and cytotoxic activities of selected compounds proved that virtual drug screening and molecular docking are suitable tools for the identification of putative drug candidates. Verbascoside was among the top 10 compounds binding to two key anti-inflammatory proteins, NLRP3 and NF-kB. Additionally, data from the NCI indicate that verbascoside is not linked to main drug resistance mechanisms., Competing Interests: Declaration of competing interest As corresponding author, I declare on behalf of all authors that there is no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Leukemia is one of the most lethal cancers worldwide and represents the sixth-leading cause of cancer deaths. The results of leukemia treatment have not been as positive as desired, and recurrence is common., Purpose: Thus, there is an urgent requirement for the development of new therapeutic drugs. Salvia multicaulis (Bardakosh) is a widespread species that contains multiple phytochemical components with anti-cancer activities., Methods: We isolated and characterized the major diterpene candesalvone B methyl ester from S. multicaulis and investigated its action as a cytotoxic agent towards sensitive and drug-resistant leukemia cells by the resazurin reduction assay. Additionally, the targeted genes and the affected molecular mechanisms attributed to the potent cytotoxic activities were discovered by transcriptome-wide mRNA expression profiling. The targets predicted to be regulated by candesalvone B methyl ester in each cell line were confirmed by qRT-PCR, molecular docking, microscale thermophoresis, and western blotting. Moreover, cell cycle distribution and apoptosis were analyzed by flow cytometry., Results: Candesalvone B methyl ester was cytotoxic with IC 50 values of 20.95 ± 0.15 µM against CCRF-CEM cells and 4.13 ± 0.10 µM against multidrug-resistant CEM/ADR5000 leukemia cells. The pathway enrichment analysis disclosed that candesalvone B methyl ester could regulate the heat-shock response signaling pathway via targeting heat shock factor 1 (HSF1) in CCRF-CEM cells and ELOVL fatty acid elongase 5 (ELOVL5) controls the fatty acid metabolism pathway in CEM/ADR5000 cells. Microscale thermophoresis showed the binding of candesalvone B methyl ester with HSF1 and ELOVL5, confirming the results of molecular docking analysis. Down-regulation of both HSF1 and ELOVL5 by candesalvone B methyl ester as detected by both western blotting and RT-qPCR was related to the reversal of drug resistance in the leukemia cells. Furthermore, candesalvone B methyl ester increased the arrest in the sub-G1 phase of the cell cycle in a dose-dependent manner from 1.3 % to 32.3 % with concomitant induction of apoptosis up to 29.0 % in CCRF-CEM leukemic cells upon inhibition of HSF1., Conclusion: Candesalvone B methyl ester isolated from S. multicaulis exerted cytotoxicity by affecting apoptosis, cell division, and modulation of expression levels of genes contributing to the heat stress signaling and fatty acid metabolism pathways that could relieve drug resistance of leukemia cells., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier GmbH.. All rights reserved.)

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused millions of infections and deaths worldwide since its emergence in Wuhan, China, in late 2019. Natural product inhibitors targeting the interaction between the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein and human angiotensin-converting enzyme 2 (ACE2), crucial for viral attachment and cellular entry, are of significant interest as potential antiviral agents. In this study a library of nitrile- and sulfur-containing natural product derived compounds were used for virtual drug screening against the RBD of the SARS-CoV-2 spike protein. The top 18 compounds from docking were tested for their efficacy to inhibit virus entry. In vitro experiments revealed that compounds 9, 14, and 15 inhibited SARS-CoV-2 pseudovirus and live virus entry in HEK-ACE2 and Vero E6 host cells at low micromolar IC 50 values. Cell viability assays showed these compounds exerted low cytotoxicity towards MRC5, Vero E6, and HEK-ACE2 cell lines. Microscale thermophoresis revealed all three compounds strongly bound to the RBDs of SARS-CoV-2, SARS-CoV-2 XBB, SARS-CoV-1, MERS-CoV, and HCoV-HKU1, with their K d values increasing as RBD sequence similarity decreased. Molecular docking studies indicated compounds 9, 14, and 15 bound to the SARS-CoV-2 spike protein RBD and interacted with hotspot amino acid residues required for the RBD-ACE2 interaction and cellular infection. These three nitrile-containing candidates, particularly compound 15, should be considered for further development as potential pan-coronavirus entry inhibitors., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Conflict of interest The authors declare that there is no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Background and Aim: Chamomile tea, renowned for its exquisite taste, has been appreciated for centuries not only for its flavor but also for its myriad health benefits. In this study, we investigated the preventive potential of chamomile ( Matricaria chamomilla L.) towards cancer by focusing on its anti-inflammatory activity., Methods and Results: A virtual drug screening of 212 phytochemicals from chamomile revealed β-amyrin, β-eudesmol, β-sitosterol, apigenin, daucosterol, and myricetin as potent NF-κB inhibitors. The in silico results were verified through microscale thermophoresis, reporter cell line experiments, and flow cytometric determination of reactive oxygen species and mitochondrial membrane potential. An oncobiogram generated through comparison of 91 anticancer agents with known modes of action using the NCI tumor cell line panel revealed significant relationships of cytotoxic chamomile compounds, lupeol, and quercetin to microtubule inhibitors. This hypothesis was verified by confocal microscopy using α-tubulin-GFP-transfected U2OS cells and molecular docking of lupeol and quercetin to tubulins. Both compounds induced G2/M cell cycle arrest and necrosis rather than apoptosis. Interestingly, lupeol and quercetin were not involved in major mechanisms of resistance to established anticancer drugs (ABC transporters, TP53 , or EGFR ). Performing hierarchical cluster analyses of proteomic expression data of the NCI cell line panel identified two sets of 40 proteins determining sensitivity and resistance to lupeol and quercetin, further pointing to the multi-specific nature of chamomile compounds. Furthermore, lupeol, quercetin, and β-amyrin inhibited the mRNA expression of the proinflammatory cytokines IL-1β and IL6 in NF-κB reporter cells (HEK-Blue Null1). Moreover, Kaplan-Meier-based survival analyses with NF-κB as the target protein of these compounds were performed by mining the TCGA-based KM-Plotter repository with 7489 cancer patients. Renal clear cell carcinomas (grade 3, low mutational rate, low neoantigen load) were significantly associated with shorter survival of patients, indicating that these subgroups of tumors might benefit from NF-κB inhibition by chamomile compounds., Conclusion: This study revealed the potential of chamomile, positioning it as a promising preventive agent against inflammation and cancer. Further research and clinical studies are recommended.

Background: Inhibition of NF-κB activity represents a strategy to treat acute myeloid leukemia, one of the most lethal leukemia types. Naphthylisoquinolines (NIQs) are cytotoxic alkaloids from lianas of the families Ancistrocladaceae and Dioncophyllaceae, which are indigenous to tropical rainforests., Purpose: Uncovering therapeutic possibilities and underlying molecular mechanisms of dioncophylline A and its derivatives towards NF-κB related cellular processes., Methods: Resazurin-based cell viability assay was performed for dioncophylline A and three derivatives on wild-type CCRF-CEM and multidrug-resistant CEM/ADR5000 cells. Transcriptome analysis was executed to discover cellular functions and molecular networks associated with dioncophylline A treatment. Expression changes obtained by mRNA microarray hybridization were confirmed using qRT-PCR. Molecular docking was applied to predict the affinity of the NIQs with NF-κB. To validate the in silico approach, NF-κB reporter assays were conducted on HEK-Blue™ Null1 cells. Cell death mechanisms and cell cycle arrest were studied using flow cytometry. The potential activity on angiogenesis was evaluated with the endothelial cell tube formation assay on HUVECs using fluorescence microscopy. Intracellular NF-κB location in HEK-Blue™ Null1 cells was visualized with immunofluorescence. Finally, the anti-tumor activity of dioncophylline A was studied by a xenograft zebrafish model in vivo., Results: Our study demonstrated that dioncophylline A and its derivatives exerted potent cytotoxicity on leukemia cells. Using Ingenuity Pathway Analysis, we identified the NF-κB network as the top network, and docking experiments predicted dioncophylline A and two of its derivatives sharing the same binding pocket with the positive control compound, triptolide. Dioncophylline A showed the best inhibitory activity in NF-κB reporter assays compared to its derivatives, caused autophagy rather than apoptosis, and induced G2/M arrest. It also prevented NF-κB translocation from the cytoplasm to the nucleus. Tube formation as an angiogenesis marker was significantly suppressed by dioncophylline A treatment. Finally, the remarkable anti-tumor activity of dioncophylline A was proven in zebrafish in vivo., Conclusion: Taken together, we report for the first time the molecular mechanism behind the cytotoxic effect of dioncophylline A on leukemia cells. Dioncophylline A showed strong cytotoxic activity, inhibited NF-κB translocation, significantly affected the NF-κB in silico and in vitro, subdued tube formation, induced autophagy, and exerted antitumor activity in vivo. Our findings enlighten both the cellular functions including the NF-κB signaling pathway and the cytotoxic mechanism affected by dioncophylline A., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier GmbH.. All rights reserved.)

Naphthylisoquinoline (NIQ) alkaloids are rising as a promising class of secondary metabolites with pharmaceutical potential. NF-κB has already been recognized as a significant modulator of cancer proliferation and drug resistance. We have previously reported the mechanisms behind the cytotoxic effect of dioncophylline A, an NIQ monomer, in leukemia cells. In the current study, we have investigated the cytotoxic effect of jozimine A 2 , an NIQ dimer, on leukemia cells in comparison to a second, structurally unsymmetric dimer, michellamine B. To this end, molecular docking was applied to predict the binding affinity of the dimers towards NF-κB, which was then validated through microscale thermophoresis. Next, cytotoxicity assays were performed on CCRF-CEM cells and multidrug-resistant CEM/ADR5000 cells following treatment. Transcriptome analysis uncovered the molecular networks affected by jozimine A 2 and identified the cell cycle as one of the major affected processes. Cell death modes were evaluated through flow cytometry, while angiogenesis was measured with the endothelial cell tube formation assay on human umbilical vein endothelial cells (HUVECs). The results indicated that jozimine A 2 bound to NF-κB, inhibited its activity and prevented its translocation to the nucleus. In addition, jozimine A 2 induced cell death through apoptosis and prevented angiogenesis. Our study describes the cytotoxic effect of jozimine A 2 on leukemia cells and explains the interactions with the NF-κB signaling pathway and the anticancer activity.

The improvement of cancer chemotherapy remains a major challenge, and thus new drugs are urgently required to develop new treatment regimes. Curcumin, a polyphenolic antioxidant derived from the rhizome of turmeric (Curcuma longa L.), has undergone extensive preclinical investigations and, thereby, displayed remarkable efficacy in vitro and in vivo against cancer and other disorders. However, pharmacological limitations of curcumin stimulated the synthesis of numerous novel curcumin analogs, which need to be evaluated for their therapeutic potential. In the present study, we calculated the binding affinities of 50 curcumin derivatives to known cancer-related target proteins of curcumin, i.e., epidermal growth factor receptor (EGFR) and nuclear factor κB (NF-κB) by using a molecular docking approach. The binding energies for EGFR were in a range of −12.12 (±0.21) to −7.34 (±0.07) kcal/mol and those for NF-κB ranged from −12.97 (±0.47) to −6.24 (±0.06) kcal/mol, indicating similar binding affinities of the curcumin compounds for both target proteins. The predicted receptor-ligand binding constants for EGFR and curcumin derivatives were in a range of 0.00013 (±0.00006) to 3.45 (±0.10) µM and for NF-κB in a range of 0.0004 (±0.0003) to 10.05 (±4.03) µM, indicating that the receptor-ligand binding was more stable for EGFR than for NF-κB. Twenty out of 50 curcumin compounds showed binding energies to NF-κB smaller than −10 kcal/mol, while curcumin as a lead compound revealed free binding energies of >−10 kcal/mol. Comparable data were obtained for EGFR: 15 out of 50 curcumin compounds were bound to EGFR with free binding energies of <−10 kcal/mol, while the binding affinity of curcumin itself was >−10 kcal/mol. This indicates that the derivatization of curcumin may indeed be a promising strategy to improve targe specificity and to obtain more effective anticancer drug candidates. The in silico results have been exemplarily validated using microscale thermophoresis. The bioactivity has been further investigated by using resazurin cell viability assay, lactate dehydrogenase assay, flow cytometric measurement of reactive oxygen species, and annexin V/propidium iodide assay. In conclusion, molecular docking represents a valuable approach to facilitate and speed up the identification of novel targeted curcumin-based drugs to treat cancer.