Two new quinolone alkaloids from Dianthus superbus var. superbus

Two new quinolone alkaloids, superbusines A (1) and B (2), were obtained from the whole plants of a Chinese medicinal plant, Dianthus superbus var. superbus. Their structures, featuring a glucosyl moiety linked with a rare 2-(hydroxymethyl)-5-(2-hydroxypropan-2-yl)phenol fragment, were determined on the basis of detailed spectroscopic analyses, and the absolute configurations were assigned by time-dependent density functional theory (TD-DFT)-based electronic circular dichroism (ECD) calculations. The two alkaloids were evaluated in a series of bioassays without showing antimicrobial, anti-inflammatory, antioxidant, cytotoxic and α-glucosidase inhibitory properties, while they exhibited slight protection against amyloid-β(Aβ)-induced injury on neuron SH-SY5Y cells.     

Cytoprotective effect against mercury chloride and bioinsecticidal activity of Eugenia jambolana Lam.

The fruit fly Drosophila melanogaster is often utilized in genetic research, and in the last decades, it has become one of best organisms for studies of human diseases and toxicological research. Mercury chloride (HgCl₂), the main representative of mercury compounds, is the target of numerous investigations, not only because of its intrinsic toxicity but also because it accounts for the toxicity of elemental mercury since the latter is converted to Hg⁺² by oxidation. Eugenia jambolana Lam. Myrtaceae, known in Brazil as “jambolão”, is of great interest because of its medicinal applications, especially its leaves and fruits. The aim of this work was to characterize, by CG–MS, the chemical constituents of the essential oil of Eugenia jambolana and to evaluate its bioinsecticidal action in the Drosophila melanogaster model, as well as to determine the cytoprotective and chelating effect of the extract of E. jambolana. The results obtained here point to the potential of essential oils as a source in biological prospecting for bioinsecticides. Because of their biodegradability, essential oils can be important tools in the biological control of pests. The results demonstrated that the extract has an allelopathic effect on lettuce seeds and that its interaction with mercury chloride allows a greater growth of the radicle and plumule of Lactuta sativa seedlings, showing that this plant can provide an alternative solution to the problem of contamination by heavy metals, besides having cytoprotective potential and moderate chelating activity.     

Electrochemical and Biological Studies on Reactivity of [VO(oda)(H2O)2], [Co(oda)(H2O)2]·H2O,and [Ni(oda)­(H2O)3]·1.5H2O Towards Superoxide Free Radicals

The reactivity of superoxide free radicals (O₂ ^{· –}) generated electrochemically towards the oxydiacetate metal complexes, namely [VO(oda)(H₂O)₂], [Co(oda)(H₂O)₂] · H₂O, and [Ni(oda)(H₂O)₃] · 1.5H₂O (oda = oxydiacetate) was examined by cyclic voltammetry. The measurements were carried out in DMSO solution using a platinum electrode. Based on the height of the anodic peak E_a that corresponds to electrochemical oxidation O₂ ^{· –} → O₂ + e, in the absence and in the presence of the compounds in the mixture, their O₂ ^{· –} scavenge ability was assessed. The influence of the type of the complex was briefly discussed. H₂O₂ was used to induce cellular injury in a mouse hippocampal cell line (HT22). The cytoprotection of chemical compounds was tested at the mitochondrial (MTT test) and plasma membrane level (LDH leakage). Dose‐dependent effect (10 and 100 μM of the complex) of investigated compounds was observed.     

ARMOR: Auto-Assembled Resilient Biomimetic Calcified Ornaments for Selective Cell Protection by Dual-Aptamer-Driven Hybridization Chain Reaction

Unlike plant and microbial cells having cell walls, the outermost layer of mammalian cell is a delicate, two-layered structure of phospholipids with proteins embedded, which is susceptible to environmental changes. It is necessary to create an “armor” on cell surface to protect cell integrity. Here, we propose an A uto-assembled R esilient bioM imetic calcified OR naments (ARMOR) strategy driven by dual-aptamer-based hybridization chain reaction (HCR) and Ca²⁺ assisted calcification for selective cell protection. This co-recognition design enhances the selectivity and leverages robust in situ signal amplification by HCR to improve the sensitivity. The calcified shell is cogenerated by crosslinking the alginate-HCR product with Ca²⁺ ion. ARMOR has high efficiency for shielding cells from environmental assaults, which can be applied to circulating tumor cell (CTC) protection, isolation, and identification, maintaining the native state and intact genetic information for downstream analysis.