Synthesis of the rearranged abietane diterpenes pygmaeocins C and D, viridoquinone, saprorthoquinone, and 1-deoxyviroxocine has been successfully achieved. The anticancer and anti-inflammatory activities of selected orthoquinonic compounds 5, 7, 13, and 19, as well as pygmaeocin C (17), were evaluated for the first time. The antitumor properties were assessed using three cancer cell lines: HT29 colon cancer cells, Hep G2 hepatocellular carcinoma cells, and B16-F10 murine melanoma cells. Compounds 5 and 13 showed the highest cytotoxicity in HT29 cells (IC₅₀ = 6.69 ± 1.2 µg/mL and IC₅₀ = 2.7 ± 0.8 µg/mL, respectively). Cytometric studies showed that this growth inhibition involved phase S cell cycle arrest and apoptosis induction, possibly through the activation of the intrinsic apoptotic pathway. Morphological apoptotic changes, including nuclear fragmentation and chromatin condensation, were also observed. Furthermore, the anti-inflammatory activity of these compounds was evaluated on the basis of their ability to inhibit nitric oxide production on the lipopolysaccharide activated RAW 264.7 macrophage cell line. Although all compounds showed high anti-inflammatory activity, with percentages between 40 and 100%, the highest anti-inflammatory potential was obtained by pygmaeocin B (5) (IC_50NO = 33.0 ± 0.8 ng/mL). Our results suggest that due to their dual roles, this type of compound could represent a new strategy, contributing to the development of novel anticancer agents.

Biosourced N-acetamide-based himachalenes were synthesized by Lewis acid catalyzed rearrangement of epoxy-himachalene derived from α-cis- and β-himachalenes, the main component of essential oil of Atlas cedar (Cedrus atlantica). Several new chiral polycyclic N-acetamide compounds were obtained with different selectivities depending on the acid used. Among the Lewis acids used, BF₃·OEt₂ under catalytic and mild conditions is efficient and selective affording the formation of chiral N-acetamides in good yields. Otherwise, using acetonitrile as solvent and reagent was proved as an efficient tool giving access to new N-acetamide-based himachalenes. A mechanism to explain the formation of the different compounds observed in the reaction mixture has also been proposed. Received: 07 July 2020 Accepted after revision: 22 September 2020 Publication Date: 28 October 2020 (online) © 2020. Thieme. All rights reserved Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany

Synthesis of the natural product prattinin A and some new derivatives has been achieved using abietic acid. The final products and a selection of intermediates were evaluated for their antibacterial activity against three human pathogenic bacteria: E. coli, P. aeruginosa, and S. aureus. The results showed that the antibacterial activity varies depending on the chemical structure of the compounds. Notably, compound 27 exhibited the most potent activity against E. coli and P. aeruginosa, with a minimal inhibitory concentration (MIC) of 11.7 µg/mL, comparable to that of the standard antibiotic ciprofloxacin, and strong activity against S. aureus, with an MIC of 23.4 µg/mL. Furthermore, we assessed the stability of these derivative compounds as potential antimicrobial agents and determined their interactions with the crystal structure of the protein receptor mutant TEM-12 from E. coli (pdb:1ESU) using molecular docking via UCSF Chimera software 1.17.3. The results suggest that 27 has potential as a natural antibiotic agent.

Background/Objectives: Metal-based coordination compounds are attracting attention in medicinal inorganic chemistry because changes in the metal centre can influence their physicochemical properties and biological responses. This study aimed to evaluate two isostructural ammonium-M(II) hydrogenophosphite hydrates, (NH₄)₂[Mg(H₂O)₆]₃(HPO₃)₄ (complex 1) and (NH₄)₂[Co(H₂O)₆]₃(HPO₃)₄ (complex 2), as bioactive systems with potential anticancer and anti-inflammatory properties. Methods: The complexes were synthesized and characterized by X-ray powder diffraction (XRPD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), density functional theory (DFT) calculations, and Hirshfeld surface analysis. Their cytotoxic activity was evaluated against B16-F10, HT29, HepG2, and HL-60 tumour cell lines. For complex 2, apoptosis, cell-cycle distribution, and mitochondrial membrane potential were analysed by flow cytometry. Nitric oxide production was measured in LPS-stimulated RAW 264.7 macrophages. Results: Complex 2 showed the highest cytotoxic activity, particularly against HL-60 leukaemia cells (IC₅₀ = 36.98 μg/mL), whereas complex 1 displayed weaker activity. Complex 2 increased apoptotic cell populations, altered cell-cycle distribution, and induced mitochondrial membrane depolarization in HL-60 cells. Both complexes reduced nitric oxide production, with complex 2 showing the strongest effect (IC₅₀ NO = 22.46 μg/mL), exceeding that of diclofenac under the experimental conditions, while complex 1 showed comparable activity to the reference drug. DFT descriptors indicated higher electronic reactivity for complex 2. Conclusions: Replacement of Mg(II) by Co(II) enhances the biological activity of this hydrogenophosphite framework. Complex 2 combines cytotoxic activity against HL-60 cells with apoptosis-associated mitochondrial dysfunction and NO-inhibitory activity in activated macrophages, supporting hydrogenophosphite-based metal complexes as bioactive coordination compounds with potential as multifunctional agents.