In this study, procyanidins fractions of dimers and trimers (F1–F2) from the Leucosidea sericea total extract (LSTE) were investigated for their chemical constituents. The total extract and the procyanidins were employed in the synthesis of gold nanoparticles (Au NPs) and fully characterized. Au NPs of 6, 24 and 21 nm were obtained using LSTE, F1 and F2 respectively. Zeta potential and in vitro stability studies confirmed the stability of the particles. The enzymatic activity of LSTE, F1, F2 and their corresponding Au NPs showed strong inhibitory alpha-amylase activity where F1 Au NPs demonstrated the highest with IC₅₀ of 1.88 µg/mL. On the other hand, F2 Au NPs displayed the strongest alpha-glucosidase activity at 4.5 µg/mL. F2 and F2 Au NPs also demonstrated the highest antioxidant activity, 1834.0 ± 4.7 μM AAE/g and 1521.9 ± 3.0 μM TE/g respectively. The study revealed not only the ability of procyanidins dimers (F1 and F2) in forming biostable and bioactive Au NPs but also, a significant enhancement of the natural products activities, which could improve the smart delivery in future biomedical applications.

We have investigated the in-vitro antioxidant activity and electrochemical redox properties of a number of natural compounds (carnosol, carnosic acid, 7-ethoxyrosmanol, ursolic acid, rosmanol and ladanein) isolated from the methanolic extract of Salvia chamelaeagnea collected from the Cape floristic region, South Africa. The results from trolox equivalent antioxidant capacity (TEAC), ferric-ion reducing antioxidant parameter (FRAP) oxygen radical absorbance capacity (ORAC), as well as the inhibition of Fe²⁺-induced lipid peroxidation showed strong antioxidant capacities for carnosol and rosmanol. A structural analysis of the compounds suggests that multiple OH substitution, conjugation and lactone ring in carnosol and rosmanol are important determinants of the free radical scavenging activity and electrochemical behavior. Pharmacophore generated demonstrates H-donor/acceptor capabilities of the most active compounds. Rosmanol, when compared to other compounds, exhibits the lowest oxidation potential value with an anodic peak potential (E_pa) value of 0.11 V, indicating that rosmanol has the highest antioxidant power, which is in good agreement with ORAC and lipid peroxidation experiments. The lipophilic nature of carnosol, carnosic acid and rosmanol enhanced their absorption and activity against oxidative stress related to the treatment of age-related diseases. These results confirm the first report on the in-vitro antioxidant and electrochemical activities of S. chamelaeagnea constituents and underline the medicinal uses of this plant as natural preservatives for skin ageing or in pharmaceutical applications.

Intrinsic characteristics possessed and exhibited by Ir(III) cyclometalated complexes need to be further examined, understood, and explored for greater value enhancement and potentiation. This work focuses primarily on the comparative studies of the ligand structures, types, and their substituent influence on the photophysical and optoelectronic properties of typical cyclometalated mono- and binuclear iridium(III) complexes in solution or solid states.

This study reports the synthesis and comparative investigation of the substituent effects of a new series of highly luminescent homoleptic tris-cyclometalated iridium(III) complexes of the type [Ir(N^˄C)₃]. These are based on two ligand type derivatives comprising of 4-fluorophenylvinylquinolines and 4-methoxyphenylvinylquinolines with electron-donating and/or electron-withdrawing groups as aryl substituents at 2-position. The structures of the ligands and their complexes were characterized by means of FT-IR, UV-Vis and NMR spectrometry complemented with photoluminescence and cyclic voltammetry. The photophysical properties of 2-aryl-4-(4-fluorophenylvinyl)quinoline and its corresponding complex were also studied using the density functional theory method. The photoluminescent properties of the ligands and the corresponding complexes showed high fluorescent intensities and quantum yields in solvents of different polarities. The photoluminescence spectra of the complexes in solid film, showed common transmission curves at longer wavelengths maximum (λ_em = 697 nm) possibly originating from the interference of scattered light of higher-order transmission of monochromators.

Several synthesized ruthenium(II) complexes, which are used as metallo-drug agents for cancer treatment, have fallen short of meeting expectations. In our continued efforts to search for potential anticancer drug agents for specific biological targets through rational design, this paper reports a facile, one-pot synthesis procedure, along with the photophysical and electro-redox properties, of three newly designed mixed-ligand ruthenium(II) complexes. These complexes contain triphenylphosphine (PPh₃), 4-imidazole acrylic acid (mza), and either functionalized or unfunctionalized polypyridines, specifically 2,2′-bipyridine-4.4′-dicarboxylic acid (Hbpy), 1,10-phenanthroline-5,6-dione (ptd), and 2,2′-bipyridine (bpy). The complexes are formulated as follows: V2 = [RuCl₂(PPh₃)bpy(mza)·3H₂O], W = [RuCl₂(PPh₃)Hbpy(mza)·H₂O] and X = [RuCl₂(PPh₃)ptd(mza)·3H₂O]. The complexes were characterized by elemental analysis, Fourier-Transform infrared spectroscopy (FT-IR), ultraviolet–visible spectroscopy (UV-vis), photoluminescence (PL), ¹H, ¹³C, ³¹P nuclear magnetic resonance (NMR) spectroscopy, and mass spectrometry (MS). The UV-vis absorption spectra, showed a broad and intense metal-to-ligand charge transfer (MLCT) band with a strong emission intensity ratio near infra-red. The maximum absorbance wavelengths λ_max were observed at 415–530 nm (ε ≈ 1.030 × 10³ M⁻¹ cm⁻¹) and λ_em 730–640 nm respectively. The structure–activity relationships relate to a set of voltage-current data, with ligand-based electrochemical redox processes occuring at the Ru(III/II) redox range of +1.15 and –0.82 V. Density functional theory (DFT), molecular docking, and pharmacokinetic calculations confirm that complexes V2, W and X exhibit superior and strong binding interactions and biological inhibition trafficking involving ERα +, WT EGFR, and ALK receptors compared to standard drugs such as Crizotinib, Doxorubicin, Gemcitabine and Lorlatinib. However, the high molecular weights and poor lypophilicity of the complexes hinder their ability to cross the blood–brain barrier (BBB), thus limiting their utility for central nervous system (CNS) targets. This study primarily focuses on the synthesis, characterization, and theoretical evaluation of complexes V2, W and X for their potential anticancer properties, which is useful in the discovery of new materials for drug design. No complementary in-vitro wet laboratory tests for anticancer or other biological methods of analysis were conducted, as they were outside the scope of the present study.