Data & Resources

Quinazolinones, particularly 9-azaglycophymines, and closely related derivatives and precursors were tested in vitro against various breast cancer cell lines representing the major types of breast tumors. Among the 49 compounds tested, azaglycophymine derivative 19 with an electron-withdrawing substituent demonstrated the most significant anti-proliferative effects, with IC50 values of around 4 µM. Extensive cell-based investigations revealed that compound 19 induced caspase-dependent apoptosis in HCC1937 (human TNBC), BT-474 (human HER2+/HR+), and 4T1 (mouse TNBC) cells. In contrast, in MDA-MB-468 (human TNBC) and MCF-7 (human HR+) cells, the cell death was induced via a non-apoptotic pathway. The in vivo efficacy of compound 19 was validated using a syngeneic orthotopic 4T1 model in BALB/c mice, resulting in significant reduction of 4T1 breast tumor growth upon intraperitoneal (i.p.) application of doses of 5 or 20 mg/kg. These findings highlight the potential of compound 19 as a promising scaffold for the development of new therapeutic agents for various types of breast cancer and a first structure-activity insight.

Peptide-drug conjugates (PDCs) have recently gained significant attention for the targeted delivery of anticancer therapeutics, mainly due to their cost-effective and chemically defined production and lower antigenicity compared to ADCs, among other benefits. In this study, we designed and synthesized novel PDCs by conjugating new thiol-functionalized tubulysin analogs (tubugis) to bombesin, a peptide ligand with a relevant role in cancer research. Two tubulysin analogs bearing ready-for-conjugation thiol groups were prepared by an on-resin multicomponent peptide synthesis strategy and subsequently tested for their stand-alone in vitro anti-proliferative activity against human cancer cells, which resulted in IC50 values in the nanomolar range. In addition, various fluorescently labeled [K5]-bombesin(6–14) peptides, non-lipidated and lipidated with fatty acid chains of variable length, were also synthesized using the versatile multicomponent chemistry. These bombesin derivatives were tested for their gastrin-related peptide receptor (GRPR)-mediated internalization into cancer cells using flow cytometry, proving that the lipid tail (especially C14) enhances the cell internalization. Using the tubugi toxins and bombesin peptides, three different bombesin-tubugi conjugates were synthesized with different cleavage propensity and lipophilicity. Preliminary in vitro experiments revealed that, depending on the linker and the presence of a lipid tail, these novel PDCs possess good to potent anticancer activity and moderate selectivity for GRPR-overexpressing cancer cells.

Balanites aegyptiaca (L.) Delile (Zygophyllaceae), also known as the desert date, is an edible fruit-producing tree popular for its nutritional and several health benefits. In this study, multi-targeted comparative metabolic profiling and fingerprinting approaches were conducted for the assessment of the nutrient primary and secondary metabolite heterogeneity in different parts, such as leaves, stems, seeds, unripe, and ripe fruits of B. aegyptiaca using nuclear magnetic resonance (NMR), ultra-performance liquid chromatography (UPLC-MS), and gas chromatography mass-spectrometry (GC-MS) based metabolomics coupled to multivariate analyses and in relation to its cytotoxic activities. NMR-based metabolomic study identified and quantified 15 major primary and secondary metabolites belonging to alkaloids, saponins, flavonoids, sugars, and amino and fatty acids. Principal component analysis (PCA) of the NMR dataset revealed α-glucose, sucrose, and isorhamnetin as markers for fruit and stem and unsaturated fatty acids for predominated seeds. Orthogonal projections to latent structure discriminant analysis (OPLS-DA) revealed trigonelline as a major distinctive metabolite in the immature fruit and isorhamnetin as a major distinct marker in the mature fruit. UPLC-MS/MS analysis using feature-based molecular networks revealed diverse chemical classes viz. steroidal saponins, N-containing metabolites, phenolics, fatty acids, and lipids as the constitutive metabolome in Balanites. Gas chromatography-mass spectroscopy (GC-MS) profiling of primary metabolites led to the detection of 135 peaks belonging to sugars, fatty acids/esters, amino acids, nitrogenous, and organic acids. Monosaccharides were detected at much higher levels in ripe fruit and disaccharides in predominate unripe fruits, whereas B. aegyptiaca vegetative parts (leaves and stem) were rich in amino acids and fatty acids. The antidiabetic compounds, viz, nicotinic acid, and trigonelline, were detected in all parts especially unripe fruit in addition to the sugar alcohol D-pinitol for the first time providing novel evidence for B. aegyptiaca use in diabetes. In vitro cytotoxic activity revealed the potential efficacy of immature fruit and seeds as cytotoxic agents against human prostate cancer (PC3) and human colorectal cancer (HCT-116) cell lines. Collectively, such detailed profiling of parts provides novel evidence for B. aegyptiaca medicinal uses.

A protocol for synthesizing triazole-containing pyrazolines and pyrazoles selectively using trifluoromethylated 5-(1,2,3-triazol-1-yl)enones as starting materials, is reported. The selectivity of the reaction was controlled by the nature of the hydrazine or derivative used: free hydrazines furnished the 1,5-regiosiomer exclusively in yields up to 98%, whereas protected hydrazines provided the 1,3-regioisomer in yields up to 77%. To demonstrate the synthetic versatility of the triazole-based enone, reactions with other unsymmetrical dinucleophiles (hydroxylamine hydrochloride and S-methyl isothiourea sulfates) allowed the selective preparation of triazole-containing isoxazoline and pyrimidine rings.

The selective N- or O-alkylation of 4-(trihalomethyl)-pyrimidin-2(1H)-ones, using 5-bromo enones/enaminones as alkylating agents, is reported. It was found that the selectivity toward the N-or O-regioisomer is driven by the substituent present at the 6-position of the pyrimidine ring, thus enabling the preparation of each isomer as the sole product, in 60−95% yields. Subsequent cyclocondensation of the enaminone moiety with nitrogen dinucleophiles led to pyrimidine−azole conjugates in 55−83% yields.

This study reports two strategies for preparing O-alkyl derivatives of 6-substituted-4-(trifluoromethyl)pyrimidin-(1H)-ones: a linear protocol of alkylation,using a CCC-building block followed by [3 + 3]-type cyclocondensation with 2-methylisothiourea sulfate and a convergent protocol based on direct alkylation, using 4-(iodomethyl)-2-(methylthio)-6-(trihalomethyl)pyrimidines. It was found that thecyclocondensation strategy is not feasible; thus, the direct chemoselective O-alkylationwas performed, and 18 derivatives of the targeted pyrimidines were obtained in 70−98%yields. The structure of the products was unambiguously determined via single crystal X-ray analyses and two-dimensional nuclear magnetic resonance experiments.

An extensive phytochemical study of a foliose lichen from Indonesia, Parmelia cetrata, resulted in the successful isolation of 13 phenol and depside derivatives (1–13) including the previously unreported depsides 3′-hydroxyl-5′-pentylphenyl 2,4-dihydroxyl-6-methylbenzoate (7), 3′-hydroxyl-5′-propylphenyl 2,4-dihydroxyl-6-methylbenzoate (8) and 3′-hydroxyl-5′-methylphenyl 2-hydroxyl-4-methoxyl-6-propylbenzoate (9). The anti-infective activity of isolated compounds was evaluated against the gram-negative bacterium Aliivibrio fischeri and the nematode Caenorhabditis elegans. 2,4-Dihydroxyl-6-pentylbenzoate (5) and lecanoric acid (6) induced growth inhibition of A. fischeri with inhibition values of 49% and 100% at a concentration of 100 µM, respectively. The antibacterial activity might be due to their free carboxyl group. A phenolic group at C4 also contributed to the antimicrobial activity of the depsides as shown for compounds 7 and 8, which caused 89% and 96% growth inhibition at 100 µM, respectively. Lecanoric acid (6) in addition possesses significant anthelmintic effects causing 80% mortality of C. elegans at 100 µg/mL.

Secretions from glandular trichomes potentially protect plants against a variety of aggressors. In the tomato clade of the Solanum genus, glandular trichomes of wild species produce a rich source of chemical diversity at the leaf surface. Previously, 7-epi-zingiberene produced in several accessions of Solanum habrochaites was found to confer resistance to whiteflies (Bemisia tabaci) and other insect pests. Here, we report the identification and characterisation of 9-hydroxy-zingiberene (9HZ) and 9-hydroxy-10,11-epoxyzingiberene (9H10epoZ), two derivatives of 7-epi-zingiberene produced in glandular trichomes of S. habrochaites LA2167. Using a combination of transcriptomics and genetics, we identified a gene coding for a cytochrome P450 oxygenase, ShCYP71D184, that is highly expressed in trichomes and co-segregates with the presence of the zingiberene derivatives. Transient expression assays in Nicotiana benthamiana showed that ShCYP71D184 carries out two successive oxidations to generate 9HZ and 9H10epoZ. Bioactivity assays showed that 9-hydroxy-10,11-epoxyzingiberene in particular exhibits substantial toxicity against B. tabaci and various microorganisms including Phytophthora infestans and Botrytis cinerea. Our work shows that trichome secretions from wild tomato species can provide protection against a wide variety of organisms. In addition, the availability of the genes encoding the enzymes for the pathway of 7-epi-zingiberene derivatives makes it possible to introduce this trait in cultivated tomato by precision breeding.

Nowadays, applying bio-organic fertilizer (e.g., chitosan, Ch) or integrating beneficial microorganisms (e.g., arbuscular mycorrhizal fungi, AMF) are among the successful strategies to promote plant growth. Here, the effect of two application modes of Ch (foliar spray or root treatment) and Ch-derived nanoparticles (NPs) on tomato plants colonized with the AMF Rhizophagus irregularis were analyzed, thereby focusing on plant biomass, flowering and mycorrhization. An increase of shoot biomass and flower number was observed in arbuscular mycorrhizal (AM) plants sprayed with Ch. The interaction with AMF, however, was reduced as shown by decreased mycorrhization rates and AM-specific gene expression. To get insights into Ch effect on mycorrhization, levels of sugars, jasmonates, abscisic acid, and the expression of two chitinase-encoding genes were determined in mycorrhizal roots. Ch had no effect on sugar and phytohormone levels, but the reduced mycorrhization was correlated with down- and upregulated expression of Chi3 and Chi9, respectively. In contrast, application of NPs to leaves and Ch applied to the soil did not show any effect, neither on mycorrhization rate nor on growth of mycorrhizal plants. Concluding, Ch application to leaves enhanced plant growth and flowering and reduced interaction with AMF, whereas root treatment did not affect these parameters.

Dalbergia monetaria is an Amazonian plant whose bark is widely used to treat urinary tract infections. This paper describes a bio-guided study of ethanolic extracts from the bark and leaves of D. monetaria, in a search for metabolites active against human pathogenic bacteria. In vitro assays were performed against 10 bacterial strains, highlighting methicillin-sensitive Staphylococcus aureus and methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa. Fractioning of the extracts was performed using instrumental and classical techniques, and samples were characterized by UHPLC-HRMS/MS. Ethyl acetate fractions from bark and leaves showed similar antibacterial activities. EAFB is enriched in isoflavone C-glucosides and EAFL enriched in proanthocyanidins. Subfractions from EAFL presented higher activity and showed a complex profile of proanthocyanidins constructed by (epi)-cassiaflavan and (epi)-catechin units, including dimers, trimers and tetramers. The fragmentation pattern emphasized the neutral loss of cassiaflavan units by quinone-methide fission. Fraction SL7-6, constituted by (ent)-cassiaflavan-(ent)-cassiaflavan-(epi)-catechin isomers, showed the lowest MIC against the S. aureus and P. aeruginosa with values corresponding to 64 and 32 µg/mL, respectively. Cassiaflavan-proanthocyanidins have not been found previously in another botanical genus, except in Cassia, and the traditional medicinal use of D. monetaria might be related to the antibacterial activity of proanthocyanidins characterized in the species.