Gouregine, an α-Gem-Dimethyltetradehydrocularine Alkaloid, and Other Aporphinoid Alkaloids from the Bark of Guatteria olivacea (Annonaceae) and Their In Vitro Cytotoxic Activities.

Guatteria olivacea R.E. Fries is an Amazonian species known as 'envira-bobó' and 'envira-fofa' and is common in the states of Amazonas, Acre, and Pará. Recently, the essential oil from the leaves of this species has shown promising antitumor activity both in vitro and in vivo. The presence of isoquinoline-derived alkaloids, including aporphinoids and tetrahydroprotoberberine alkaloids, has also been previously reported. In our ongoing search for bioactive compounds from Annonaceae Amazonian plants, the bark of G. olivacea was investigated via classical chromatography techniques, which revealed nine compounds, eight isoquinoline-derived alkaloids, a rare alkaloid with a α-gem-dimethyltetradehydrocularine structure known as gouregine, seven known aporphinoid alkaloids: isopiline, O-methylisopiline, melosmine, 9-hydroxyiguattescine, dihydromelosmine, lysicamine, and guattouregidine, and one known pimaradiene diterpene: acanthoic acid. All the isolated compounds were described for the first time in the bark of G. olivacea, and their structures were elucidated by extensive analyses of their 1D and 2D NMR spectra in combination with MS data. The NMR data of the alkaloids isopiline, O-methylisopiline, melosmine, dihydromelosmine, and guattouregidine were revised due to incomplete data in the literature and some ambiguities. The in vitro cytotoxic activities of the isolated compounds were evaluated against human cancer (HepG2, KG-1a, and HCT116) and noncancerous (MRC-5) cell lines via the Alamar blue assay after 72 h of incubation. Among the compounds evaluated against human cancer cell lines, the most active was the oxoaporphine alkaloid lysicamine, which has strong activity against HCT116 cells, with an IC50 value of 6.64 µg/mL (22.79 µmol/L). Melosmine had a moderate effect on HCT116 cells, with an IC50 value of 16.77 µg/mL (49.70 µmol/L), whereas acanthoic acid had moderate effects on HepG2 and HCT116 cells, with IC50 values of 14.63 µg/mL (48.37 µmol/L) and 21.25 µg/mL (70.25 µmol/L), respectively.

Uncovering Metabolic Alterations in HCT-116 Colon Cancer Cells upon Exposure to Bamboo Leaf Extract Obtained from Guadua incana Londoño.

Metabolic alterations are increasingly recognized as important aspects of colorectal cancer (CRC), offering potential avenues for identifying therapeutic targets. Previous studies have demonstrated the cytotoxic potential of bamboo leaf extract obtained from Guadua incana (BLEGI) against HCT-116 colon cancer cells. However, the altered metabolic pathways in these tumor cells remain unknown. Therefore, this study aimed to employ an untargeted metabolomic approach to reveal the metabolic alterations of the endometabolome and exometabolome of HCT-116 cells upon exposure to BLEGI treatment. First, a chemical characterization of the BLEGI was conducted through liquid chromatography coupled with mass spectrometry (LC-MS). Next, we assessed cell viability via MTT and morphological analysis using an immunofluorescence assay against colon cancer cells, and anti-inflammatory activity using an LPS-stimulated macrophage model. Subsequently, we employed LC-MS and proton nuclear magnetic resonance (1H-NMR) to investigate intra- and extracellular changes. Chemical characterization primarily revealed the presence of compounds with a flavone glycoside scaffold. Immunofluorescence analysis showed condensed chromatin and subsequent formation of apoptotic bodies, suggesting cell death by apoptosis. The results of the metabolomic analysis showed 98 differential metabolites, involved in glutathione, tricarboxylic acid cycle, and lipoic acid metabolism, among others. Additionally, BLEGI demonstrated significant nitric oxide (NO) inhibitory capacity in macrophage cells. This study enhances our understanding of BLEGI's possible mechanism of action and provides fresh insights into therapeutic targets for treating this disease.

Indium(III) complexes with lapachol: cytotoxic effects against human breast tumor cells and interactions with DNA.

Lapachol (2-hydroxy-3-(3-methylbut-2-en-1-yl)naphthalene-1,4-dione) is a 1,4-naphthoquinone-derived natural product that presents numerous bioactivities and was shown to have cytotoxic effects against several human tumor cells. Indium(III) complexes with a variety of ligands also exhibit antineoplastic activity. Indium(III) complexes [In(lap)Cl2].4H2O (1), [In(lap)2Cl(Et3N)] (2), [In(lap)3]·2H2O (3) [In(lap)(bipy)Cl2] bipy = 2,2'-bipyridine (4) and [In(lap)(phen)Cl2] phen = 1,10-phenanthroline (5) were obtained with 2-hydroxy-3-(3-methylbut-2-en-1-yl)naphthalene-1,4-dione (lapachol). Crystal structure determinations for (4) and (5) revealed that the indium(III) center is coordinated to two O atoms from lapachol, two N atoms from 1,10-phenanthroline or 2,2'-bipyridine, and two chloride anions, in a distorted octahedral geometry. Although both complexes (4) and (5) interacted with CT-DNA in vitro by an intercalative mode, only 5 exhibited cytotoxicity against MCF-7 and MDA-MB breast tumor cells. 1,10-phenanthroline and complex (5) presented cytotoxic effects against MCF-7 and MDA-MB cells, with complex (5) being threefold more active than 1,10-phenanthroline on MCF-7 cells. In addition, complex (5) significantly reduced the formation of MDA-MB-231 colonies in a clonogenicity assay. The foregoing results suggest that further studies on the cytotoxic effects and cellular targets of complex (5) are of utmost relevance.

Ethanolic Extract from Fruits of Pintoa chilensis, a Chilean Extremophile Plant. Assessment of Antioxidant Activity and In Vitro Cytotoxicity.

Pintoa chilensis is a shrub with yellow flowers that reach up to two meters high, endemic of the Atacama Region in Chile. This species grows under special environmental conditions such as low altitude, arid areas, and directly sun-exposed habitats. In the present study, ethanolic extract was obtained from fruits of P. chilensis, and then partitioned in solvents of increasing polarity to obtain five fractions: hexane (HF), dichloromethane (DF), ethyl acetate (AF), and the residual water fraction (QF). The antioxidant activity of extracts was evaluated by using the DPPH, ABTS, and FRAP methods. The results show that the antioxidant capacity of P. chilensis is higher than that reported for other plants growing in similar environments. This effect is attributed to the highest content of flavonoids and total phenols found in P. chilensis. On the other hand, the cell viability of a breast cancer cell line (MCF-7) and a non-tumor cell line (MCF-10A) was assessed in the presence of different extract fractions. The results indicate that the hexane fraction (HF) exhibits the highest cytotoxicity on both cell lines (IC50 values equal to 35 and 45 µg/mL), whereas the dichloromethane fraction (DF) is the most selective one. The GC-MS analysis of the dichloromethane fraction (DF) shows the presence of fatty acids, sugars, and polyols as major components.

Alliaxylines A-E: five new mexicanolides from the stem barks of Dysoxylum alliaceum (Blume) Blume ex A.Juss.

A total of five new mexicanolides (1-5), namely alliaxylines A-E, together with two known limonoids 6 and 7, were isolated and identified from Dysoxylum alliaceum (Blume) Blume ex. A.Juss. (Meliaceae). The structures of these compounds were elucidated based on extensive spectroscopic analyses, including HR-ESI-MS, UV, IR, 1D, and 2D NMR, as well as theoretical stimulation of NMR shifts with the DP4 + algorithm. Consequently, this study aimed to examine cytotoxic activities of these compounds against MCF-7 and A549 cell lines. The results implied that compound 2 was the most potent against the two tested cells, with IC50 values of 34.95 ± 0.21 and 44.39 ± 1.03 µM.

Effects of the tetravanadate [V4O12]4- anion on the structural, magnetic, and biological properties of copper/phenanthroline complexes.

The aim to access linked tetravanadate [V4O12]4- anion with mixed copper(II) complexes, using α-amino acids and phenanthroline-derived ligands, resulted in the formation of four copper(II) complexes [Cu(dmb)(Gly)(OH2)]2[Cu(dmb)(Gly)]2[V4O12]·9H2O (1) [Cu(dmb)(Lys)]2[V4O12]·8H2O (2), [Cu(dmp)2][V4O12]·C2H5OH·11H2O (3), and [Cu(dmp)(Gly)Cl]·2H2O (4), where dmb = 4,4'-dimethioxy-2,2'-bipyridine; Gly = glycine; Lys = lysine; and dmp = 2,9-dimethyl-1,10-phenanthroline. The [V4O12]4- anion is functionalized with mixed copper(II) units in 1 and 2; while in 3, it acts as a counterion of two [Cu(dmp)]2+ units. Compound 4 crystallized as a unit that did not incorporate the vanadium cluster. All compounds present magnetic couplings arising from Cu⋯O/Cu⋯Cu bridges. Stability studies of water-soluble 3 and 4 by UV-Vis spectroscopy in cell culture medium confirmed the robustness of 3, while 4 appears to undergo ligand scrambling over time, resulting partially in the stable species [Cu(dmp)2]+ that was also identified by electrospray ionization mass spectrometry at m/z = 479. The in vitro cytotoxicity activity of 3 and 4 was determined in six cancer cell lines; the healthy cell line COS-7 was also included for comparative purposes. MCF-7 cells were more sensitive to compound 3 with an IC50 value of 12 ± 1.2 nmol. The tested compounds did not show lipid peroxidation in the TBARS assay, ruling out a mechanism of action via reactive oxygen species formation. Both compounds inhibited cell migration at 5 µM in wound-healing assays using MCF-7, PC-3, and SKLU-1 cell lines, opening a new window to study the anti-metastatic effect of mixed vanadium-copper(II) systems.

Design of Two New Sulfur Derivatives of Perezone: In Silico Study Simulation Targeting PARP-1 and In Vitro Study Validation Using Cancer Cell Lines.

Poly-ADP-Ribose Polymerase (PARP-1) is an overexpressed enzyme in several carcinomas; consequently, the design of PARP-1 inhibitors has acquired special attention. Hence, in the present study, three compounds (8-10) were produced through a Michael addition protocol, using phenylmethanethiol, 5-fluoro-2-mercaptobenzyl alcohol, and 4-mercaptophenylacetic acid, respectively, as nucleophiles and perezone as the substrate, expecting them to be convenient candidates that inhibit PARP-1. It is convenient to note that in the first stage of the whole study, the molecular dynamics (MD) simulations and the quantum chemistry studies of four secondary metabolites, i.e., perezone (1), perezone angelate (2), hydroxyperezone (3), and hydroxyperezone monoangelate (4), were performed, to investigate their interactions in the active site of PARP-1. Complementarily, a docking study of a set of eleven sulfur derivatives of perezone (5-15) was projected to explore novel compounds, with remarkable affinity to PARP-1. The molecules 8-10 provided the most adequate results; therefore, they were evaluated in vitro to determine their activity towards PARP-1, with 9 having the best IC50 (0.317 µM) value. Additionally, theoretical calculations were carried out using the density functional theory (DFT) with the hybrid method B3LYP with a set of base functions 6-311++G(d,p), and the reactivity properties were compared between the natural derivatives of perezone and the three synthesized compounds, and the obtained results exhibited that 9 has the best properties to bind with PARP-1. Finally, it is important to mention that 9 displays significant inhibitory activity against MDA-MB-231 and MCF-7 cells, i.e., 145.01 and 83.17 µM, respectively.

Anti-biofilm and anti-inflammatory active diterpene isolated from the fruit of Xylopia benthamii R.E.Fr.

Xylopia benthamii (Annonaceae) is a plant with limited phytochemical and pharmacological evidence. Thus, using LC-MS/MS, we performed exploratory analyses of the fruit extract of X. benthamii, resulting in the tentative identification of alkaloids (1-7) and diterpenes (8-13). Through the application of chromatography techniques with the extract of X. benthamii, two kaurane diterpenes were isolated, xylopinic acid (9) and ent-15-oxo-kaur-16-en-19-oic acid (11). Their structures were established using spectroscopy (NMR 1D/2D) and mass spectrometry. The isolated compounds were submitted to anti-biofilm analysis against Acinetobacter baumannii, anti-neuroinflammatory and cytotoxic activity in BV-2 cells. Compound 11 (201.75 µM) inhibited 35% of bacterial biofilm formation and high anti-inflammatory activity in BV-2 (IC50 = 0.78 µM). In conclusion, the results demonstrated that compound 11 was characterized for the first time with pharmacological potential in the development of new alternatives for studies with neuroinflammatory diseases.

Synthesis, Cytotoxic Activity and In Silico Study of Novel Dihydropyridine Carboxylic Acids Derivatives.

To aid the possible prevention of multidrug resistance in tumors and cause lower toxicity, a set of sixteen novel dihydropyridine carboxylic acids derivatives 3a-p were produced; thus, the activation of various ynones with triflic anhydride was performed, involving a nucleophilic addition of several bis(trimethylsilyl) ketene acetals, achieving good yields requiring easy workup. The target molecules were unequivocally characterized by common spectroscopic methods. In addition, two of the tested compounds (3a, and 3b) were selected to perform in silico studies due to the highest cytotoxic activity towards the HCT-15 cell line (7.94 ± 1.6 µM and 9.24 ± 0.9 µM, respectively). Employing theoretical calculations with density functional theory (DFT) using the B3LYP/6-311++G(d,p) showed that the molecular parameters correlate adequately with the experimental results. In contrast, predictions employing Osiris Property Explorer showed that compounds 3a and 3b present physicochemical characteristics that would likely make it an orally active drug. Moreover, the performance of Docking studies with proteins related to the apoptosis pathway allowed a proposal of which compounds could interact with PARP-1 protein. Pondering the obtained results (synthesis, in silico, and cytotoxic activity) of the target compounds, they can be judged as suitable antineoplastic agent candidates.

Cytotoxic Activity of Wild Plant and Callus Extracts of Ageratina pichinchensis and 2,3-Dihydrobenzofuran Isolated from a Callus Culture.

Ageratina pichinchensis (Kunth) R.M. King & H. Rob. belongs to the Asteraceae family and is a plant native to Mexico to which several biological properties are attributed. In this study, the cytotoxic effect of four extracts from the wild plants and two extracts from A. pichinchensis callus culture were evaluated against carcinogenic cell lines including prostate carcinoma, cervical cancer, hepatocellular carcinoma, hepatoma human, lung cancer, and cellular keratinocytes. The extracts were obtained with ethyl acetate and methanol using both leaves and stems or the callus. Only the ethyl acetate extract of the callus culture influenced the cervical cancer cell line (HeLa) with an IC50 of 94.79 ± 2.0 µg/mL. From the ethyl acetate callus extract, 2,3-dihydrobenzofuran was isolated and purified and also evaluated against cancer cells. The cytotoxic evaluation of this compound showed a significant effect against the HeLa cell line with an IC50 of 23.86 ± 2.5 µg/mL. Our results contribute to the development of biotechnological alternatives and extraction processes to produce compounds with possible potential against certain types of human cancer.

Two new naphthoquinone derivatives from Sinningia conspicua (Gesneriaceae).

Two new naphthoquinones, 7-hydroxy-2-O-methyldunniol (1) and 7-methoxy-2-O-methyldunniol (2) were isolated from the tubers of Sinningia conspicua (Seem.) G. Nicholson (Gesneriaceae). Nine known compounds were also obtained: 7-methoxydunniol (3), dunniol (4), 7-methoxy-α-dunnione (5), 7-hydroxydunnione (6), 2,4,4',6-tetramethoxychalcone (7), loureirin B (8), allo-calceolarioside A (9), ß-sitosterol (10) and stigmasterol (11). This is the first report of compounds 3 and 5 in Sinningia. n-Hexane, ethyl acetate and ethanol extracts, and compounds 1-5 were tested for cytotoxic activity against PC-3 (prostate) and SKMEL 103 (melanoma) human tumour cell lines and also against the 3T3 (fibroblast) non-cancer cell line. All samples were inactive.

Advances in the Properties of Incomptine A: Cytotoxic Activity and Downregulation of Hexokinase II in Breast Cancer Cell Lines.

Breast cancer treatments are limited by the cancer subtype and its selectivity towards tumor cells, hence the importance of finding compounds that increase the survival of healthy cells and target any subtype. Incomptine A (IA) is a sesquiterpene lactone with demonstrated cytotoxic activity. In this study, through in vitro assays, it was observed that IA has similar cytotoxic activity between the subtypes triple negative, HER2+, and luminal A of the breast cancer cell lines. IA cytotoxic activity is higher in cancer than in nontumorigenic cells, and its selectivity index for cancer cells is more than that of the drug doxorubicin. Molecular docking and its in silico comparison with the 2-Deoxyglucose inhibitor suggest that IA could bind to Hexokinase II (HKII), decreasing its expression. Since we did not find changes in the expression of the glycolytic pathway, we suppose that IA could affect the antiapoptotic function of HKII in cancer cells. The IA-HKII union would activate the voltage-gated anion channel 1 (VDAC1), resuming apoptosis. Therefore, we suggest that IA could be used against almost any subtype and that its cytotoxic effect could be due to the reactivation of apoptosis in breast cancer cells.

Chemical Profiles and Cytotoxic Activities of Essential Oils from Six Species of Baccharis Subgenus Coridifoliae (Asteraceae).

Several Baccharis species are popularly known in traditional medicine as "carquejas", "vassouras", "ervas-santas" and "mio-mios", and are used as anti-inflammatories, digestives, and diuretics. This study aimed to investigate the chemical compositions and cytotoxic activities of essential oils (EOs) of six Baccharis species belonging to subgenus Coridifoliae, namely B. albilanosa, B. coridifolia, B. erigeroides, B. napaea, B. ochracea, and B. pluricapitulata. GC/MS analyses of the EOs showed that the oxygenated sesquiterpenes spathulenol (7.32-38.22 %) and caryophyllene oxide (10.83-16.75 %) were the major components for all the species. The EOs of almost all species were cytotoxic against cancer (BT-549, KB, SK-MEL and SK-OV-3) and normal kidney (VERO and LLC-PK1) cell lines, whereas B. erigeroides EO showed cytotoxicity only against LLC-PK1. This article augments the current knowledge about the chemical-biological properties of Baccharis subgenus Coridifoliae and discusses the therapeutic potentials of these economically unexploited plants.

Finding a Novel Chalcone-Cinnamic Acid Chimeric Compound with Antiproliferative Activity against MCF-7 Cell Line Using a Free-Wilson Type Approach.

In this work, we carried out the design and synthesis of new chimeric compounds from the natural cytotoxic chalcone 2',4'-dihydroxychalcone (2',4'-DHC, A) in combination with cinnamic acids. For this purpose, a descriptive and predictive quantitative structure-activity relationship (QSAR) model was developed to study the chimeric compounds' anti-cancer activities against human breast cancer MCF-7, relying on the presence or absence of structural motifs in the chalcone structure, like in a Free-Wilson approach. For this, we used 207 chalcone derivatives with a great variety of structural modifications over the α and ß rings, such as halogens (F, Cl, and Br), heterocyclic rings (piperazine, piperidine, pyridine, etc.), and hydroxyl and methoxy groups. The multilinear equation was obtained by the genetic algorithm technique, using logIC50 as a dependent variable and molecular descriptors (constitutional, topological, functional group count, atom-centered fragments, and molecular properties) as independent variables, with acceptable statistical parameter values (R2 = 86.93, Q2LMO = 82.578, Q2BOOT = 80.436, and Q2EXT = 80.226), which supports the predictive ability of the model. Considering the aromatic and planar nature of the chalcone and cinnamic acid cores, a structural-specific QSAR model was developed by incorporating geometrical descriptors into the previous general QSAR model, again, with acceptable parameters (R2 = 85.554, Q2LMO = 80.534, Q2BOOT = 78.186, and Q2EXT = 79.41). Employing this new QSAR model over the natural parent chalcone 2',4'-DHC (A) and the chimeric compound 2'-hydroxy,4'-cinnamate chalcone (B), the predicted cytotoxic activity was achieved with values of 55.95 and 17.86 µM, respectively. Therefore, to corroborate the predicted cytotoxic activity compounds A and B were synthesized by two- and three-step reactions. The structures were confirmed by 1H and 13C NMR and ESI+MS analysis and further evaluated in vitro against HepG2, Hep3B (liver), A-549 (lung), MCF-7 (breast), and CasKi (cervical) human cancer cell lines. The results showed IC50 values of 11.89, 10.27, 56.75, 14.86, and 29.72 µM, respectively, for the chimeric cinnamate chalcone B. Finally, we employed B as a molecular scaffold for the generation of cinnamate candidates (C-K), which incorporated structural motifs that enhance the cytotoxic activity (pyridine ring, halogens, and methoxy groups) according to our QSAR model. ADME/tox in silico analysis showed that the synthesized compounds A and B, as well as the proposed chalcones C and G, are the best candidates with adequate drug-likeness properties. From all these results, we propose B (as a molecular scaffold) and our two QSAR models as reliable tools for the generation of anti-cancer compounds over the MCF-7 cell line.

Non-natural amino acids into LfcinB-derived peptides: effect in their (i) proteolytic degradation and (ii) cytotoxic activity against cancer cells.

The dimeric peptide 26[F]: (RRWQWRFKKLG)2-K-Ahx has exhibited a potent cytotoxic effect against breast cancer cell lines, with position 26 (F) being the most relevant for anti-cancer activity. In this investigation, six analogues of the 26[F] peptide were synthesized in which the 26th position was replaced by non-natural hydrophobic amino acids, finding that some modifications increased the resistance to proteolytic degradation exerted by trypsin or pepsin. Additionally, these modifications increased the cytotoxic effect against breast cancer cells and generated cell death mediated by apoptosis pathways, activating caspases 8 and 9, and did not compromise the integrity of the cytoplasmic membrane. Finally, it was found that the modified peptides have a broad spectrum of action, since they also have a cytotoxic effect against the HeLa human cervical cancer cell line. Peptide 26[F] was inoculated in mice by ip administration and the lethal dose 50 (LD50) was between 70 and 140 mg kg-1. While for the 26[1-Nal]: (RRWQWR-1-Nal-KKLG)2-K-Ahx peptide, a dose-response test was performed, and the survival rate was 100%. These results suggested that these peptides are safe in this animal model and could be considered as promissory to develop a treatment against breast cancer.

Cytotoxic, Anti-Hemolytic, and Antioxidant Activities of Ruta chalepensis L. (Rutaceae) Extract, Fractions, and Isolated Compounds.

Ruta chalepensis is an herb used to treat various ailments, and its potential cytotoxic effects on different tumor cell lines have been extensively studied. The present study aimed to evaluate the cytotoxic activity of R. chalepensis methanol extract (RCME), sub-partitions obtained from solvents of increasing polarity, and major compounds, as well as their hemolytic, anti-hemolytic, and antioxidant potential. The in vitro cytotoxic activity against the human hepatocarcinoma (HEP-G2) and the murine lymphoma cell line (L5178Y-R) was evaluated using the colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay, whereas selectivity indices (SIs) were determined by comparing cytotoxicity against normal African green monkey kidney cells (VERO) and human peripheral blood mononuclear cells (PBMC). Hemolytic and anti-hemolytic activities were evaluated on human erythrocytes. The most effective cytotoxic treatment was evaluated for nitric oxide release by J774A.1 macrophages. Antioxidant activity of R. chalepensis material was also determined. Results showed that RCME produced significant (p < 0.05) cytotoxicity in HEP-G2 (IC50 = 1.79 µg/mL) and L5178Y-R (IC50 = 1.60 µg/mL) cells and exhibited high SIs (291.50 and 114.80, respectively). In addition, the n-hexane fraction (RCHF) showed an IC50 of 18.31 µg/mL in HEP-G2 cells and an SI of 9.48 in VERO cells, whereas the chloroform fraction (RCCF) evidenced an IC50 of 1.60 µg/mL in L5178Y-R cells and an SI of 34.27 in PBMC cells. Chalepensin (CHL), rutamarin (RTM), and graveolin (GRV), which are major components of R. chalepensis, showed high activity against L5178Y-R cells, with IC50 of 9.15, 15.13 and SI of 45.08 µg/mL, respectively. In addition, CHL, RTM, and GRV showed SIs of 24.76, 9.98, and 3.52, respectively, when compared with PBMC cells. RCME at concentrations of 125 µg/mL and 250 µg/mL, significantly (p < 0.05) decreased nitrite production in J774A.1 cells, when exposed to lipopolysaccharide. This study demonstrated that RCME showed significant cytotoxic activity against HEP-G2 and L5178Y-R cells, without affecting normal VERO, PBMC, and J774A.1 cells.

Development of Copper Complexes with Diimines and Dipicolinate as Anticancer Cytotoxic Agents.

Coordination complexes may act as anticancer agents. Among others, the formation of the complex may facilitate the ligand uptake by the cell. Searching for new copper compounds with cytotoxic activity, the complex Cu-dipicolinate was studied as a neutral scaffold to form ternary complexes with diimines. A series of [Cu(dipicolinate)(diimine)] complexes (where diimine: Phenanthroline, phen, 5-NO2-phenanthroline, 4-methyl-phenanthroline, neocuproine, 3,4,7,8-tetramethyl-phenanthroline, tmp, bathophenanthroline, bipyridine, dimethyl-bipyridine, as well as the ligand 2,2-dipyridil-amine, bam) were synthesized and characterized both in the solid state, including a new crystal structure of [Cu2(dipicolinate)2(tmp)2]·7H2O. Their chemistry in aqueous solution was explored by UV/vis spectroscopy, conductivity, cyclic voltammetry, and electron paramagnetic resonance studies. Their DNA binding was analyzed by electronic spectroscopy (determining Kb values), circular dichroism, and viscosity methods. The cytotoxicity of the complexes was assessed on human cancer cell lines MDA-MB-231, MCF-7 (breast, the first triple negative), A549 (lung epithelial) and A2780cis (ovarian, Cisplatin-resistant), and non-tumor cell lines MRC-5 (lung) and MCF-10A (breast). The major species are ternary, in solution and solid state. Complexes are highly cytotoxic as compared to Cisplatin. Complexes containing bam and phen are interesting candidates to study their in vivo activity in triple-negative breast cancer treatment.

Cytotoxic Activity, Topoisomerase I Inhibition and In Silico Studies of New Sesquiterpene-aryl Ester Derivatives of (-) Drimenol.

In this study, we aimed to evaluate two sets of sesquiterpene-aryl derivatives linked by an ester bond, their cytotoxic activities, and their capacity to activate caspases 3/7 and inhibit human topoisomerase I (TOP1). A total of 13 compounds were synthesized from the natural sesquiterpene (-)-drimenol and their cytotoxic activity was evaluated in vitro against three cancer cell lines: PC-3 (prostate cancer), HT-29 (colon cancer), MCF-7 (breast cancer), and an immortalized non-tumoral cell line (MCF-10). From the results, it was observed that 6a was the most promising compound due to its cytotoxic effect on three cancer cell lines and its selectivity, 6a was 100-fold more selective than 5-FU in MCF-7 and 20-fold in PC-3. It was observed that 6a also induced apoptosis by caspases 3/7 activity using a Capsase-Glo-3/7 assay kit and inhibited TOP1. A possible binding mode of 6a in a complex with TOP1-DNA was proposed by docking and molecular dynamics studies. In addition, 6a was predicted to have a good pharmacokinetic profile for oral administration. Therefore, through this study, it was demonstrated that the drimane scaffold should be considered in the search of new antitumoral agents.

Cytotoxic Activity of Amaryllidaceae Plants against Cancer Cells: Biotechnological, In Vitro, and In Silico Approaches.

Cancer is a major cause of death and an impediment to increasing life expectancy worldwide. With the aim of finding new molecules for chemotherapeutic treatment of epidemiological relevance, ten alkaloid fractions from Amaryllidaceae species were tested against six cancer cell lines (AGS, BT-549, HEC-1B, MCF-7, MDA-MB 231, and PC3) with HaCat as a control cell line. Some species determined as critically endangered with minimal availability were propagated using in vitro plant tissue culture techniques. Molecular docking studies were carried out to illustrate binding orientations of the 30 Amaryllidaceae alkaloids identified in the active site of some molecular targets involved with anti-cancer activity for potential anti-cancer drugs. In gastric cancer cell line AGS, the best results (lower cell viability percentages) were obtained for Crinum jagus (48.06 ± 3.35%) and Eucharis bonplandii (45.79 ± 3.05%) at 30 µg/mL. The research focused on evaluating the identified alkaloids on the Bcl-2 protein family (Mcl-1 and Bcl-xL) and HK2, where the in vitro, in silico and statistical results suggest that powelline and buphanidrine alkaloids could present cytotoxic activity. Finally, combining experimental and theoretical assays allowed us to identify and characterize potentially useful alkaloids for cancer treatment.

Chilensosides E, F, and G-New Tetrasulfated Triterpene Glycosides from the Sea Cucumber Paracaudina chilensis (Caudinidae, Molpadida): Structures, Activity, and Biogenesis.

Three new tetrasulfated triterpene glycosides, chilensosides E (1), F (2), and G (3), have been isolated from the Far-Eastern sea cucumber Paracaudina chilensis (Caudinidae, Molpadida). The structures were established based on extensive analysis of 1D and 2D NMR spectra and confirmed by HR-ESI-MS data. The compounds differ in their carbohydrate chains, namely in the number of monosaccharide residues (five or six) and in the positions of sulfate groups. Chilensosides E (1) and F (2) are tetrasulfated pentaosides with the position of one of the sulfate groups at C-3 Glc3, and chilensoside G (3) is a tetrasulfated hexaoside. The biogenetic analysis of the glycosides of P. chilensis has revealed that the structures form a network due to the attachment of sulfate groups to almost all possible positions. The upper semi-chain is sulfated earlier in the biosynthetic process than the lower one. Noticeably, the presence of a sulfate group at C-3 Glc3-a terminal monosaccharide residue in the bottom semi-chain of compounds 1 and 2-excludes the possibility of this sugar chain's further elongation. Presumably, the processes of glycosylation and sulfation are concurrent biosynthetic stages. They can be shifted in time in relation to each other, which is a characteristic feature of the mosaic type of biosynthesis. The hemolytic action of compounds 1-3 against human erythrocytes and cytotoxic activities against five human cancer cell lines were tested. The compounds showed moderate hemolytic activity but were inactive against cancer cells, probably because of their structural peculiarities, such as the combination of positions of four sulfate groups.