Analytical applications of 1,10-anthraquinones: A review

Generation of singlet oxygen catalyzed by the room-temperature-stable anthraquinone anion radical

The chemical nature and the catalytic selectivity of the complex of anthraquinone and potassium tert-butoxide, AQ-KOtBu, in generating singlet oxygen (¹O₂) have been studied using a high-level ab initio method and density functional theory (DFT). The results suggest that the stable catalytic center of the AQ anion radical (semiquinone, [AQ˙]^-) can be produced at room temperature, which is due to the strong delocalization characteristics of electrons in potassium atoms. Two experimentally observed complexes, the ground state AQ-KOtBu, i.e., C₍₁₎, and the photoexcited AQ-KOtBu, i.e., C₍₂₎, can be distinguished via the two different electronic states (π-type and σ-type) of the tert-butoxide group. More interestingly, the catalytic selectivity of AQ-KOtBu to generate ¹O₂ was investigated using multistate density functional theory (MSDFT), and the results suggest that only open-shell ¹O₂ rather than the closed-shell component can be generated. This work explores the electronic structure and the catalytic nature of AQ-KOtBu, which is of great importance for the application of AQ and its derivatives.

Anticancer activity and evaluation of apoptotic genes expression of 2-azetidinones containing anthraquinone moiety

Nowadays, one of the principal causes of death in the world is cancer. A series of 2-azetidinones containing anthraquinone moiety with various substituents were synthesized using [2 + 2] ketene-imine cycloaddition (Staudinger ketene-imine cycloaddition), and their cytotoxicity against some human cancer and normal cell lines was evaluated. Some of these hybrid compounds showed moderate to significant cytotoxicity against breast carcinoma (MCF7), colon carcinoma (HCT116), prostate carcinoma (PC3), and neuroblastoma (SKNMC) cell lines via MTT assay. Surprisingly, hybrid 4gh with the best anticancer activity demonstrated very good antibacterial and antifungal activities. This compound was selected to study to test on human fibroblast (Hu02) normal cell and comparison with doxorubicin. While 2-azetidinone 4gh represented similar cytotoxicity against cancer cell lines compared to doxorubicin, the 2-azetidinone demonstrated lower cytotoxicity against human fibroblast (Hu02) than doxorubicin. Further real-time PCR investigation displayed the expression of Bcl-xl, KI-67, TPX2 and BAX genes were significantly increased or decreased as desired in the cancer cell lines studied by treatment with doxorubicin or 2-azetidinone-anthraquinone 4gh. Molecular docking studies represented that hybrid 4gh strongly fitted the active site of topoisomerase II (PDB 4G0V) with hydrogen bond and hydrophobic interactions.

Synthesis, in vitro biological evaluation and in silico molecular docking studies of novel β-lactam-anthraquinone hybrids

Schiff bases from 2-aminoanthraquinone have been prepared by reaction with aldehydes and used to prepare novel β-lactam-anthraquinone hybrids via [2+2] ketene-imine cycloaddition (Staudinger reaction) reaction. In vitro antibacterial studies of all synthesized compound were carried out against three gram-positive strains Staphylococcus aureus (Methicillin-resistant strain), Enterococcus faecium (Vancomycin-resistant strain) and Bacillus subtilis, and two gram-negative strains Escherichia coli and Pseudomonas aeruginosa. These compounds were further evaluated for their in vitro antifungal activity against Candida albicans, Aspergillus niger and Trichophyton mentagrophytes. Hybrid compounds showed moderate to excellent antibacterial and antifungal activities. Surprisingly, among the tested compounds, some of them revealed equal antibacterial and antifungal properties and even better than standards. In addition, results demonstrated that the new hybrids are very promising antibacterial agents against resistant strains. Also molecular docking studies were carried out by Autodoc software. Penicillin-binding protein 2a (PDB ID: 1VQQ) from methicillin-resistant Staphylococcus aureus strain used as a target which good binding interactions were observed.

UV/Visible spectra of a series of natural and synthesised anthraquinones: experimental and quantum chemical approaches

Root decoctions of anthraquinone-containing plants are often taken as postpartum tonic and aphrodisiac. Anthraquinones are known for their diverse biological activities, especially antioxidant and anticancer. A series of 35 anthraquinones was generated by isolation from Rubiaceae plants and synthesis. Their UV/vis spectrum depends on the nature and relative positions of auxochromic substituents on the basic skeleton. To predict the maximum absorption bands for the current series of anthraquinones, excited sate calculations were performed using TD-DFT, CIS, ZINDO methods. The results showed that the use of PBE0 or its combination with B3LYP and B3P86 hybrid functionals are the most suitable to reproduce accurately the experimental λ_MAX. The structure–property relationships (SPRs) were established based on structural and electronic properties of the anthraquinones and showed (i) the importance of the number and position of OH groups and (ii) the positive contribution of the electrophilicity and hardness as electronic descriptors on position and amplitude of the maximum absorption bands.

Selective fluorometric detection of pyrophosphate by interaction with alizarin red S-dimethyltin(IV) complex

Highly selective detection of pyrophosphate in the presence of inorganic phosphate, halides, acetate, ATP, other nucleotides and phosphate esters in neutral aqueous solutions is achieved by using fluorescent dimethyltin(iv)-alizarin red S complex.

Spectrophotometric Determination of Trace Amount of Copper(II) Ion Based on Complexation with an Anthraquinone Derivative

The spectrophotometric determination of Cu(II) with an anthraquinone derivative (Alizarin Red S) has been investigated. The experimental conditions, such as the pH of the sample and concentration of ligand, were optimized. This method is simple and sensitive for determination of Cu(II) ion. The interfering effects of diverse ions were investigated. Copper ion was determined by measuring the absorbance of the Cu(II)-ARS complex at 510 nm. Beer's law was obeyed over the concentration range of 0.011 - 0.320 mmol dm(-3) and the detection limit (S/N = 3) was 0.038 microg cm(-3). The relative standard deviation at 20 microg cm(-3) was 1.02% (n = 5). The method was applied for real samples.