Search Results (7)

Research on titanium-oxo complexes (TOCs) is usually focused on their structure and photocatalytic properties. Findings from these investigations further sparked our interest in exploring their potential biological activities. In this study, we focused on the synthesis and structure of a compound with the general formula [Ti₈O₂(OⁱPr)₂₀(man)₄] (1), which was isolated from the reaction mixture of titanium(IV) isopropoxide with mandelic acid (Hman) in a molar ratio of 4:1. The structure (1) was determined using single-crystal X-ray diffraction, while spectroscopic studies provided insights into its physicochemical properties. To assess the potential practical applications of (1), its microcrystals were incorporated into a polymethyl methacrylate (PMMA) matrix, yielding composite materials of the type PMMA + (1) (2 wt.%, 5 wt.%, 10 wt.%, and 20 wt.%). The next stage of our research involved the evaluation of the antimicrobial activity of the obtained materials. The investigations performed demonstrated the antimicrobial activity of pure (1) and its composites (PMMA + (1)) against both Gram-positive and Gram-negative strains. Furthermore, MTT tests conducted on the L929 murine fibroblast cell line confirmed the lack of cytotoxicity of these composites. Our study identified (1) as a promising antimicrobial agent, which is also may be use for producing composite coatings. Full article

At times of fruit skin failure, reticulation made of a wound-periderm is formed below the cracked skin in order to seal the damaged tissue. Preceding investigations shed light on the mechanisms underlying the formation of fruit skin reticulation, demonstrating that the walls of periderm cells are heavily suberized and lignified. However, the relative contribution of the suberin pathway to these processes, as well as the association between suberin contents in the periderm tissue and reticulation degree, are largely unknown. To strengthen our understanding on these important physiological and agricultural aspects, we comparatively profiled skin tissues of a collection of smooth- and reticulated-skin melon (Cucumis melo) cultivars for suberin monomer composition via gas chromatography-mass spectrometry (GC-MS). This metabolite profiling approach accompanied by statistical tools highlighted the fundamental chemical differences between the skin of smooth fruit made of a typical cuticle, to the skin of reticulated fruit made of large amounts of archetypal suberin building blocks including hydroxycinnamic acids, very long chain fatty acids, fatty alcohols, α-hydroxyacids, ω-hydroxyacids, and α,ω-diacids. Next, using image analysis we generated ‘reticulation maps’ and calculated the relative densities of reticulation. We then performed correlation assays in order to monitor suberin monomers that specifically correlate well with reticulation degree. Nonetheless, total suberin contents and most suberin building blocks did not show high correlations with reticulation degree, further suggesting that additional factors are likely to influence and regulate these processes. Altogether, the data provided vital information regarding the relative contribution of the suberin pathway to periderm formation and skin reticulation. Full article

Quercus rotundifolia bark was studied regarding anatomical, chemical, and antioxidant properties from trees in two sites in southern Portugal and are here reported for the first time. The general structure and anatomy of Q. rotundifolia bark showed a rhytidome with sequential undulated and anastomosed periderms with a small proportion of cork, while the phloem included broad rays with strong cell sclerification, groups of sclereids with embed large prismatic crystals, and abundant druses in parenchyma cells. The mean chemical composition was 15.5% ash, 1.6% dichloromethane extractives, 6.4% ethanol and 9.3% water extractives, 3.0% suberin, 30.5% total lignin, and 33.8% carbohydrates. Carbohydrates included mainly glucose (50.7% of total monomers) and xylose (23.8%), with uronic (3.0%) and acetic acids (1.0%). Suberin was mainly composed of ω-hydroxyacids (48.0% of all compounds) and α,ω-diacids (19.5%). The main compounds found in the lipophilic extracts were triterpenes (43.6%–56.2% of all compounds) and alkanoic acids (32.7%–41.7%). Phenolic content was high especially in the ethanol extracts, ranging from 219.5–572.9 mg GAE/g extract and comprising 162.5–247.5 CE/g extract of flavonoids and 41.2–294.1 CE/g extract of condensed tannins. The extracts revealed very good antioxidant properties with IC₅₀ values of 4.4 µg ethanol extract/mL and 4.7 µg water extract/mL. Similar anatomical, chemical, and antioxidant characteristics were found in the bark from both sites. The high phenolic content and excellent antioxidant characteristics of polar extracts showed holm oak barks to be a promising natural source of antioxidants with possible use in industry and pharmaceutical/medical areas. Full article

Since the European Union (EU) announced their animal testing ban in 2013, all animal experiments related to cosmetics have been prohibited, creating a demand for alternatives to animal experiments for skin studies. Here, we investigated whether an ex vivo live porcine skin model can be employed to study the safety and skin barrier-improving effects of hydroxyacids widely used in cosmetics for keratolytic peels. Glycolic acid (1–10%), salicylic acid (0.2–2%), and lactobionic acid (1.2–12%) were used as representative substances for α-hydroxyacid (AHA), β-hydroxyacid (BHA), and polyhydroxyacid (PHA), respectively. When hydroxyacids were applied at high concentrations on the porcine skin every other day for 6 days, tissue viability was reduced to 50–80%, suggesting that the toxicity of cosmetic ingredients can be evaluated with this model. Based on tissue viability, the treatment scheme was changed to a single exposure for 20 min. The protective effects of a single exposure of hydroxyacids on skin barrier function were evaluated by examining rhodamine permeability and epidermal structural components of barrier function using immunohistochemistry (IHC) and immunofluorescence (IF) staining. Lactobionic acid (PHAs) improved skin barrier function most compared to other AHAs and BHAs. Most importantly, trans-epidermal water loss (TEWL), an important functional marker of skin barrier function, could be measured with this model, which confirmed the significant skin barrier-protective effects of PHAs. Collectively, we demonstrated that the ex vivo live full-thickness porcine skin model can be an excellent alternative to animal experiments for skin studies on the safety and efficacy of cosmetic ingredients. Full article

Abstract: Indolizyl-5-lithium anions react with succinic and phtalic anhidrides giving 1,4-keto acids, with oxallyl chloride giving 1,2-diketone, and with ethyl pyruvate giving 1,2-hydroxyacid. However, with α-halocarbonyl compounds, they react in different ways, forming the products of selective bromination at C-5 (with α-bromo ketones and esters of α-bromo acids) and 5-chloroacetyl indolizines. Full article

Biodegradable poly(α-hydroxyacids) have gained increasing interest in the biomedical field for their use as cell microcarriers thanks to their biodegradability, biocompatibility, tunable mechanical properties/degradation rates and processability. The synthesis of these poly(α-hydroxyacids) can be finely controlled to yield (co)polymers of desired mechanical properties and degradation rates. On the other hand, by simple emulsion-solvent evaporation techniques, microspheres of controlled size and size distribution can be fabricated. The resulting microspheres can be further surface-modified to enhance cell adhesion and proliferation. As a result of this process, biodegradable microcarriers with advanced functionalities and surface properties that can be directly employed as injectable cell microcarriers are obtained. Full article

The synthesis of alkyl aryl ketones using a mandelic acid dioxolanone as a synthetic equivalent (Umpolung) of the benzoyl carbanion is reported. The methodology involves alkylation of the mandelic acid dioxolanone, hydrolysis of the dioxolanone moiety in the alkylated products and oxidative decarboxylation of the resulting α-hydroxyacids. The last step is carried out in a catalytic aerobic way using a Co (III) complex in the presence of pivalaldehyde under very mild conditions. Full article