Ruthenium(II) complexes of 2,2′-bipyridine-5,5′-dicarboxylic acid: Synthesis, structure, DNA binding, cytotoxicity and antioxidant activity

Identification and quantification of bipyridyl dicarboxylic acid isomers by ion mobility spectrometry

The identification of positional isomers is of interest because different isomers have different chemical or biological functions and applications. The analysis of positional isomers is sometimes challenging since they have similar chemical structures and properties. For example, the analysis of mass cannot identify different positional isomers because they have identical mass-to-charge ratios and show a single mass peak in mass spectrometry. In this study, an efficient and simple qualitative and quantitative analytical method for differentiating 2,2'-bipyridine-3,3'-dicarboxylic acid (3,3'-BDA), 2,2'-bipyridine-4,4'-dicarboxylic acid (4,4'-BDA), and 2,2'-bipyridine-5,5'-dicarboxylic acid (5,5'-BDA) was developed by using ion mobility spectrometry (IMS). The results revealed that the three BDA isomers formed non-covalent complexes with cyclodextrins (CDs) and Mg2+ ions in the gas phase: [β-CD+3,3'/4,4'/5,5'-BDA+Mg]2+ and [γ-CD+3,3'/4,4'/5,5'-BDA+Mg]2+, which were distinguished by measuring the mobility of the complexes because of their spatial conformational differences. The peak-to-peak resolution (Rp-p) values of the three isomers of [γ-CD+3,3'/4,4'/5,5'-BDA+Mg]2+ reached 2.983 and 2.892, respectively. The conformations of the ternary complexes simulated by the theoretical calculations revealed the different interactions and shapes of the stereoisomers, and the predicted results agreed with the experimental results. Simultaneously, further studies on the collisional dissociation of the ternary complexes revealed that the dissociation energies of the different complex ions varied were different owing to the diverse different conformations. Finally, the relative quantitative analysis of the different isomers in mixed samples was performed and satisfactory linearity results (R2 > 0.99) were obtained. Thus, an effective analytical method was proposed for the identification and quantification of BDA isomers without chemical derivatization, offering a promising approach for the identification of similar derivatives or positional isomers that could be applied in various fields including chemicals and pharmaceuticals.

Copper-Curcumin-Bipyridine Dicarboxylate Complexes as Anticancer Candidates

In this study, copper complexes with Curcumin (Cur) and 2,2'-bipyridine-5,5'-dicarboxylic acid (BPYD) were synthesized and their cytotoxicity on the MDA-MB-231 cell lines was evaluated. The resulting complex was characterized using FTIR, UV/VIS, CHNS, TGA, ICP-MS, and Mass spectroscopy techniques. The in-vitro cytotoxicity was studied on the MDA-MB-231 as a cancerous cell line and the HUVEC as a normal cell line. Reactive oxygen species (ROS) production was measured using the 2',7'-dichlorofluorescein diacetate (DCFDA) test in the MDA-MB-231 cancer cell lines. The in-vitro assays revealed that all synthesized copper complexes exhibited a higher cytotoxicity effect than carboplatin as a positive control on the MDA-MB-231 cells. While the synthesized complexes exhibited cytotoxic effects on cancerous cell lines, they are practically safe on normal cells. The Cu-Cur-BPYD complexes (a5 & b5) exhibited higher cytotoxicity on MDA-MB-231 cells with IC₅₀ s around 4.9 and 2.3 mM, respectively. It can be concluded that the synthesized Cu-Cur-BPYD complexes (a5 & b5) could be considered effective anticancer candidates in complementary studies.

Ruthenium complex Λ-WH0402 induces hepatocellular carcinoma LM6 (HCCLM6) cell death by triggering the Beclin-1-dependent autophagy pathway

To evaluate the anticancer mechanism of the new ruthenium complex-Λ-WH0402 at the cellular level, the in vitro cytotoxicity of Λ-WH0402 was investigated on 10 human tumor cell lines. Λ-WH0402 was found to have higher anticancer activity than cisplatin toward human liver cancer HCCLM6 cells that have high tumor metastatic characteristics. Meanwhile, Λ-WH0402 showed an antimetastatic effect on HCCLM6 cells in vitro, mostly through its effect on cell adhesion, invasion and migration. In addition, Λ-WH0402 significantly reduced tumor metastasis to the lungs in orthotopic mouse hepatocellular cancer (HCC) models induced by HCCLM6 cells. Furthermore, Λ-WH0402 exerted an inhibitory effect on tumor cell growth and proliferation and induced dose-dependent cell cycle arrest in the S phase in HCCLM6 cells. Immunoblotting analysis showed that Λ-WH0402 not only decreased the expression of antiapoptotic protein Bcl-2 and nutrient-deprivation autophagy factor-1 (NAF-1), but also significantly increased the expression of Beclin-1 in HCCLM6 cells. More importantly, we identified that Λ-WH0402 treatment reduced the interaction between Bcl-2 and Beclin-1, and increased the expression of autophagic activation marker LC3B-II in HCCLM6 cells. On the whole, our results suggested that the anitcancer activity of Λ-WH0402 is mediated through promoting the Beclin-1-dependent autophagy pathway in HCCLM6 cells.