Labdane conjugates protect cardiomyocytes from doxorubicin-induced cardiotoxicity

The cardiovascular side effects associated with doxorubicin (DOX), a wide spectrum anticancer drug, have limited its clinical application. Therefore, to explore novel strategies with cardioprotective effects, a series of new labdane conjugates were prepared (6a-6c and 8a-8d) from the natural diterpene labdanodiol (1). These hybrid compounds contain anti-inflammatory privileged structures such as naphthalimide, naphthoquinone, and furanonaphthoquinone. Biological activity of these conjugates against DOX-induced cardiotoxicity was tested in vitro and the potential molecular mechanisms of protective effects were explored in H9c2 cardiomyocytes. Three compounds 6c, 8a, and 8b significantly improved cardiomyocyte survival, via inhibition of reactive oxygen species-mediated mitogen-activated protein kinase signaling pathways (extracellular signal-regulated kinase and c-Jun N-terminal kinase) and autophagy mediated by Akt activation. Some structure-activity relationships were outlined, and the best activity was achieved with the labdane-furonaphthoquinone conjugate 8a having an N-cyclohexyl substituent. The findings of this study pave the way for further investigations to obtain more compounds with potential cardioprotective activity.This study was supported by Grant RTI2018‐094356‐BC21 from the Ministerio de Ciencia, Innovación y Universidades (MICIU) to A. E.‐B., I. C., L. G.‐C., and B. H.; Grant PI17/00012 and PI20/00018 from the Instituto de Salud Carlos III to S. H. These projects are also cofunded by the European Regional Development Fund (FEDER). A. A. and S. O.‐R. thank the Cabildo de Tenerife (Agustín de Betancourt Program).S

Labdane conjugates protect cardiomyocytes from doxorubicin‐induced cardiotoxicity

The cardiovascular side effects associated with doxorubicin (DOX), a wide spectrum anticancer drug, have limited its clinical application. Therefore, to explore novel strategies with cardioprotective effects, a series of new labdane conjugates were prepared (6a–6c and 8a–8d) from the natural diterpene labdanodiol (1). These hybrid compounds contain anti‐inflammatory privileged structures such as naphthalimide, naphthoquinone, and furanonaphthoquinone. Biological activity of these conjugates against DOX‐induced cardiotoxicity was tested in vitro and the potential molecular mechanisms of protective effects were explored in H9c2 cardiomyocytes. Three compounds 6c, 8a, and 8b significantly improved cardiomyocyte survival, via inhibition of reactive oxygen species‐mediated mitogen‐activated protein kinase signaling pathways (extracellular signal‐regulated kinase and c‐Jun N‐terminal kinase) and autophagy mediated by Akt activation. Some structure–activity relationships were outlined, and the best activity was achieved with the labdane–furonaphthoquinone conjugate 8a having an N‐cyclohexyl substituent. The findings of this study pave the way for further investigations to obtain more compounds with potential cardioprotective activity

Design, synthesis and biological evaluation of new embelin derivatives as CK2 Inhibitors

A new series of furan embelin derivatives was synthesized and characterized as ATPcompetitive CK2 inhibitors. The new compounds were efficiently synthesized using a multicomponent approach from embelin (1), aldehydes and isonitriles through a Knoevenagel condensation/ Michael addition/ heterocyclization. Several compounds with inhibitory activities in the low micromolar or even submicromolar were identified. The most active derivative was compound 4l (2-(tert-butylamino)-3-(furan-3-yl)-5- hydroxy-6-undecylbenzofuran-4,7-dione) with an IC50 value of 0.63 μM. It turned out to be an ATP competitive CK2 inhibitor with a Ki value determined to be 0.48 μM. Docking studies allowed the identification of key ligand-CK2 interactions, which could help to further optimize this family of compounds as CK2 inhibitor

Phenylisoxazole-3/5-Carbaldehyde Isonicotinylhydrazone Derivatives: Synthesis, Characterization, and Antitubercular Activity

14 pags, 5 figs, 3 tabs, 1 schEight new phenylisoxazole isoniazid derivatives, 3-(2′-fluorophenyl)isoxazole-5-carbaldehyde isonicotinylhydrazone (1), 3-(2′-methoxyphenyl)isoxazole-5-carbaldehyde isonicotinylhydrazone (2), 3-(2′-chlorophenyl)isoxazole-5-carbaldehyde isonicotinylhydrazone (3), 3-(3′-clorophenyl)isoxazole-5-carbaldehyde isonicotinylhydrazone (4), 3-(4′-bromophenyl)isoxazole-5-carbaldehyde isonicotinylhydrazone (5), 5-(4′-methoxiphenyl)isoxazole-3-carbaldehyde isonicotinylhydrazone (6), 5-(4′-methylphenyl)isoxazole-3-carbaldehyde isonicotinylhydrazone (7), and 5-(4′-clorophenyl)isoxazole-3-carbaldehyde isonicotinylhydrazone (8), have been synthesized and characterized by FT-IR, 1H-NMR, 13C-NMR, and mass spectral data. The 2D NMR (1H-1H NOESY) analysis of 1 and 2 confirmed that these compounds in acetone-d6 are in the trans(E) isomeric form. This evidence is supported by computational calculations which were performed for compounds 1-8, using DFT/B3LYP level with the 6-311++G(d,p) basis set. The in vitro antituberculous activity of all the synthesized compounds was determined against the Mycobacterium tuberculosis standard strains: sensitive H37Rv (ATCC-27294) and resistant TB DM97. All the compounds exhibited moderate bioactivity (MIC = 0.34-0.41 μM) with respect to the isoniazid drug (MIC = 0.91 μM) against the H37Rv sensitive strain. Compounds 6 (X = 4′-OCH3) and 7 (X = 4′-CH3) with MIC values of 12.41 and 13.06 μM, respectively, were about two times more cytotoxic, compared with isoniazid, against the resistant strain TB DM97.W. H. and F. C. acknowledge Universidad de Lima Scientific Research Institute for the financial support to carry out this research work. E. S. thanks Financiamiento Basal para Centros Cientificos y Tecnologicos de Excelencia, AFB10008. J. Z. D. thanks Consejo Superior de Investigacion Cientifica (CSIC, Spain). S. O. thanks Ministerio de Ciencias, Innovacion y Universidades (MICINN (RTI2018-094356-B-C21)) and Cabildo de Tenerife (Agust ' in de Betancourt Program).Peer reviewe

Dehydrohispanolone Derivatives Attenuate the Inflammatory Response through the Modulation of Inflammasome Activation

The NLRP3 inflammasome plays a critical role in inflammation-mediated human diseases and represents a promising drug target for novel anti-inflammatory therapies. Hispanolone is a labdane diterpenoid isolated from the aerial parts of Ballota species. This diterpenoid and some derivatives have demonstrated anti-inflammatory effects in classical inflammatory pathways. In the present study, a series of dehydrohispanolone derivatives (1-19) was synthesized, and their anti-inflammatory activities toward NLRP3 inflammasome activation were evaluated. The structures of the dehydrohispanolone analogues produced were elucidated by NMR spectroscopy and mass spectrometry. Four derivatives significantly inhibited IL-1β secretion, with 15 and 18 being the most active (IC50 = 18.7 and 13.8 μM, respectively). Analysis of IL-1β and caspase-1 expression revealed that the new diterpenoids 15 and 18 are selective inhibitors of the NLRP3 inflammasome, reinforcing the previously demonstrated anti-inflammatory properties of hispanolone derivatives.This study was supported by grant PI17/00012 from Instituto de Salud Carlos III to S. Hortelano and grant RTI2018-094356-B-C21 from Ministerio de Ciencia, Innovación y Universidades (MICIU) to AEB and BH, grant Pro ID 2017010071 from Agencia Canaria de Investigación, Innovación y Sociedad de la Información (ACIISI) to AEB. These projects are also co-funded by the European Regional Development Fund (FEDER). LGC received a predoctoral fellowship award from the Spanish Ministry of Education, Culture and Sports (FPU17/03519). Á.A. and S.O.R. thank the Cabildo de Tenerife (Agustín de Betancourt Program).S

Phenolic and quinone methide nor-triterpenes as selective NLRP3 inflammasome inhibitors

Dysregulated inflammasome activity, particularly of the NLRP3 inflammasome, is associated with the development of several inflammatory diseases. The study of molecules directly targeting NLRP3 is an emerging field in the discovery of new therapeutic compounds for the treatment of inflammatory disorders. Friedelane triterpenes are biologically active phytochemicals having a wide range of activities including anti-inflammatory effects. In this work, we evaluated the potential anti-inflammatory activity of phenolic and quinonemethide nor-triterpenes (1-11) isolated from Maytenus retusa and some semisynthetic derivatives (12-16) through inhibition of the NLRP3 inflammasome in macrophages. Among them, we found that triterpenes 6 and 14 were the most potent, showing markedly reduced caspase-1 activity, IL-1β secretion (IC50 = 1.15 µM and 0.19 µM, respectively), and pyroptosis (IC50 = 2.21 µM and 0.13 µM, respectively). Further characterization confirmed their selective inhibition of NLRP3 inflammasome in both canonical and non-canonical activation pathways with no effects on AIM2 or NLRC4 inflammasome activation.This study was supported by Instituto de Salud Carlos III (PI17CIII/00012, PI20CIII/00018); Spanish Ministry of Science, Innovation and Universities (RTI2018-094356-B-C21) and Agencia Canaria de Investigación, Innovación y Sociedad de la Información (Pro ID 2021010037). LGC received a predoctoral fellowship award and a complementary mobility grant from the Spanish Ministry of Universities (FPU17/03519, EST22/00224). AA and SOR thanks to Cabildo de Tenerife (Agustín de Bethancourt Program).N

Indole-3-carbaldehyde Semicarbazone Derivatives: Synthesis, Characterization, and Antibacterial Activities

The two-dimensional NMR (in acetone-d6) spectral data revealed that the molecules 1 and 2 in solution are in the cisE isomeric form. This evidence is supported by DFT calculations at the B3LYP/6-311++G(d,p) level of theory where it was shown that the corresponding most stable conformers of the synthesized compounds have a cisE geometrical configuration, in both the gas and liquid (acetone and DMSO) phases. The in vitro antibacterial activity of compounds 1-4 was determined against Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Pseudomonas aeruginosa and Escherichia coli) bacteria. Among all the tested semicarbazones, 1 and 2 exhibited similar inhibitory activities against Staphylococcus aureus (MIC = 100 and 150 µg/mL, respectively) and Bacillus subtilis (MIC = 100 and 150 µg/mL, respectively). On the other hand, 3 and 4 were relatively less active against the tested bacterial strains compared with 1, 2, and tetracycline. © 2020 Fernando Carrasco et al

Lawsone, Juglone, and β‑Lapachone Derivatives with Enhanced Mitochondrial-Based Toxicity

Naphthoquinones are among the most active natural products obtained from plants and microorganisms. Naphthoquinones exert their biological activities through pleiotropic mechanisms that include reactivity against cell nucleophiles, generation of reactive oxygen species (ROS), and inhibition of proteins. Here, we report a mechanistic antiproliferative study performed in the yeast <i>Saccharomyces cerevisiae</i> for several derivatives of three important natural naphthoquinones: lawsone, juglone, and β-lapachone. We have found that (i) the free hydroxyl group of lawsone and juglone modulates toxicity; (ii) lawsone and juglone derivatives differ in their mechanisms of action, with ROS generation being more important for the former; and (iii) a subset of derivatives possess the capability to disrupt mitochondrial function, with β-lapachones being the most potent compounds in this respect. In addition, we have cross-compared yeast results with antibacterial and antitumor activities. We discuss the relationship between the mechanistic findings, the antiproliferative activities, and the physicochemical properties of the naphthoquinones