The complex cis-(Cl,Cl)-[RuCl₂(terpy)(NO)]Cl (1) has been synthesized by the reaction of [RuCl₃(H₂O)₂(NO)] with terpyridine (terpy) and characterized by various spectroscopic, analytical techniques and using electronic structure calculation (DFT) methods. The cytotoxic activity and the DNA-binding properties of 1 have also been studied using biochemical techniques. The results establish unequivocally that 1 corresponds to a so-called [RuNO]⁶ species, which readily releases the nitrosyl ligand upon irradiation with a mercury lamp in acetonitrile solution. DFT calculations provided a satisfactory description of structural, bonding, electronic and related properties of the new compound and throw light on the mechanism of the photo-induced NO release. Screening on A2780 (human ovarian carcinoma) cell lines showed significant cytotoxicity with an IC₅₀ value of 0.49 µM. ³¹P and ²³Na NMR spectroscopy along with electrophoretic mobility studies illustrated that complex 1 primarily binds by coordination to DNA without any π-interaction between the planar terpy ligand and the DNA bases, while weak electrostatic interactions could not be excluded. Studies on the inhibition of the restriction enzymes DraI and SmaI revealed that 1 prefers the guanine and cytosine bases of DNA.

A general method for the synthesis of chloro(polypyridyl)ruthenium conjugated peptide complexes via a solid-phase strategy is described. The method is applied to synthesize two positional isomers of the complex [Ru(terpy)(4-CO₂H-4′-Mebpy-Gly-L-His-L-LysCONH₂)Cl](PF₆). Even though the separation of the isomers was only partially achieved chromatographically, the isomers were unambiguously assigned by NMR spectroscopy. The interactions of the complex [Ru(terpy)(4-CO₂H-4′-Mebpy-Gly-L-His-L-LysCONH₂)Cl](PF₆) with CT-DNA and plasmid DNA, have been studied with various spectroscopic techniques, showing that (i) the complexes coordinatively bind to DNA preferring the bases guanine and cytosine over the bases thymine and adenine after hydrolysis of the coordinated chloride, (ii) electrostatic interactions between the complex cation and the polyanionic DNA chain assist this binding (iii) only in the case of one isomer the peptide does interact further with DNA as evidenced from ³¹P NMR spectroscopy, (iv) DNA unwinding occurs in all cases with high binding ratio (Ru/base) values (r > 0.3).

Diastereomeric oligopyridine–ruthenium(II)–amino acid conjugated complexes of the general formulas Λ- and Δ-[Ru(bpy)₂(4,4′(CO₂Y)₂-bpy)]²⁺, where Y = L-AlaCONH₂, L-LysCONH₂, L-HisCONH₂, L-TyrCONH₂), were synthesized and characterized. Their binding properties with ct-DNA and the oligonucleotide duplex d(5′CGCGCG-3′)₂ , by means of circular dichroism (CD), NMR spectroscopy and DNA thermal denaturation (T_m ) curves were studied. CD and T_m data indicate that all diastereomeric complexes bind to the DNA major groove, Δ-diastereomers in a similar manner, while Λ-diastereomers in dependence of the nature of the amino acid. NMR studies of d(5′CGCGCG-3′)₂ , and the complexes Δ-1, Δ-2, Λ-1 and Λ-2 indicate that Δ-1 and Δ-2 were bound having the ancillary bpy ligands towards the DNA groove, while the corresponding Λ-1 and Λ-2 were orientated in a similar way, facing the ligand 4,4′(CO₂Y)₂bpy towards the DNA major groove. Photoinduced DNA cleavage was observed in all cases studied, which take place through singlet oxygen production. Δ-4 and Λ-4 show the lower photoinduced cleavage yield, probably because the singlet oxygen (¹O₂) oxidizes not only the DNA phosporodiesteric bonds but the tyrosine's phenolic OH bond as well.

Extra virgin olive oil (EVOO) is recognized for its numerous health benefits, attributed to its rich phenolic components. NMR has emerged as a prevalent technique for precisely identifying these compounds. Among Mediterranean countries, Greece stands as the third-largest producer of olives, with the Epirus region notably advancing in olive cultivation, contributing significantly to the dynamic growth of the region. In this study, an NMR method was employed based on the acquisition of a ¹H NMR spectrum along with multiple resonant suppression in order to increase the sensitivity. Using the above method, 198 samples of extra virgin olive oil, primarily sourced from the Epirus region, were analyzed, and both the qualitative and quantitative aspects of the phenolic compounds were obtained. In addition, we examined the effects of various factors such as variety, harvest month, and region origin on the phenolic compounds’ concentration. The results revealed an average total phenolic content of 246 mg/kg, closely approaching the EU health claim limit of 250 mg/kg. Approximately 15% of the samples were confidently characterized as high-phenolic olive oil. The highest concentrations were observed in the Thesprotia samples, with several Lianolia varieties exceeding the total phenolic content of 400 mg/kg. Statistical tests demonstrated a significant influence of the olive variety and the month of fruit harvest on phenolic component concentration, followed by the region of origin. A very strong correlation was noted between the total phenolics content and the levels of oleocanthal and oleacein, with a correlation coefficient (r) of 0.924. Upon optimization of all factors affecting olive oil quality, the majority of the EVOOs from the Epirus region have the potential to be characterized as high in phenolic content.