ABSTRACT
Nowadays, advanced extraction techniques and highly sensitive metabolic profiling methods are effectively employed to get new information on plant chemical constituents. Among them wild medicinal plants or their parts, with large and ancient use in folk medicine, are investigated for their potential functional use and cultivation. In this context, Inula viscosa leaves engaged our attention. A simple experimental design, based on Soxhlet extraction and chromatographic fractionation, allowed us to obtain the investigated polyphenol fraction (IvE). UHPLC-HRMS analyses revealed shikimoyl depsides of caffeic acid and unusual dihydrobenzofuran lignans as main secondary metabolites. These compounds, together with cinchonain-type phenols, and hydroxycinnamoyl flavonol glycosides, are reported for the first time in inula. Overall, forty-three secondary metabolites were identified. The extract exerted a remarkable antiradical activity towards DPPH⢠and ABTS+â¢. Furthermore, it was able to inhibit cell viability and mitochondrial redox activity of neuroblastoma, hepatoblastoma and colon carcinoma cells, whereas it did not affect cell density of HaCaT cells immortalized human keratinocytes. As detected by the oxidant-sensing probe 2',7'-dichlorodihydrofluorescein diacetate, the inhibitory responses seemed to be related to IvE-induced increase of intracellular reactive oxygen species (ROS). The obtained results highlighted that inula leaves, nowadays even undervalued and unexplored, could be considered a renewable source of nutraceutical compounds.
Subject(s)
Antioxidants/pharmacology , Inula/chemistry , Plant Extracts/pharmacology , Plant Leaves/chemistry , Polyphenols/pharmacology , Antioxidants/chemistry , Antioxidants/isolation & purification , Benzothiazoles/antagonists & inhibitors , Biphenyl Compounds/antagonists & inhibitors , Cell Proliferation/drug effects , Cell Survival/drug effects , Cells, Cultured , Chromatography, High Pressure Liquid , Humans , Mitochondria/drug effects , Mitochondria/metabolism , Molecular Structure , Picrates/antagonists & inhibitors , Plant Extracts/chemistry , Plant Extracts/isolation & purification , Polyphenols/chemistry , Polyphenols/isolation & purification , Reactive Oxygen Species/metabolism , Sulfonic Acids/antagonists & inhibitors , Tandem Mass SpectrometryABSTRACT
New organic-inorganic hybrid materials were synthesized by an acid catalysed sol-gel approach, using silicon alkoxide and low molecular weight polyethylene glycol (PEG400) as inorganic and organic precursor, respectively. Chlorogenic acid (CGA), an antioxidant natural phenol compound, enriched further the organic component. Hybrids synthesized, all identical in terms of their starting materials, but differing in terms of their relative proportions, were characterized by means of Fourier Transform InfraRed (FTIR) measurements, UV-Vis spectroscopy, and UHPLC-HRMS analysis. The preservation of the intrinsic chlorogenic acid ability to scavenge, in a dose-dependent manner, radical species was investigated by directly exposing the hybrids to DPPH radical and ABTS radical cation. The relative ratio of both the natural compound and PEG heavily affected the antiradical response, suggesting that chemical interactions in the established network were able, based on components' ratio, to differently mask and/or display the CGA moieties, commonly deemed relevant for antioxidant power exerting. Cell culture MTT assay was used to assess the biocompatibility of hybrid materials towards fibroblast NIH-3â¯T3 cells and neuroblastoma SH-SY5Y cells. Cells tested appeared differently responsive. In particular, a marked cell viability increase was observed when hybrids with low PEG amount (6%) and high CGA (15%) were directly exposed to fibroblast cells, whose mitochondrial redox activity was negatively affected by hybrid synthesized using the highest organic component rate (both PEG and CGA). Cell viability and morphology of human neuroblastoma SH-SY5Y cells were broadly compromised regardless of organic/inorganic starting materials ratio, suggesting the ability of hybrids to exert pro-oxidant effect towards tumour cells and to selectively interfere with their growth. The hybrids, able to elicit cleverly anti- or proliferative effects, were also shown to be bioactive. In fact, a biologically active hydroxyapatite layer was observed to be formed on the surface of the smart synthesized materials. This feature, which makes them a valuable bonding interface with tissues, opens new scenario aiming at further investigating the employment of natural phenol compounds in versatile sol-gel synthesis routes.
Subject(s)
Biocompatible Materials/chemical synthesis , Chlorogenic Acid/chemistry , Phase Transition , Polyethylene Glycols/chemistry , Animals , Biocompatible Materials/chemistry , Cell Line, Tumor , Cell Shape , Cell Survival , Humans , Mice , NIH 3T3 Cells , Silicon Dioxide/chemistry , Spectroscopy, Fourier Transform Infrared , X-Ray DiffractionABSTRACT
The current cancer treatment scenario lacks drugs acting as both radiosensitizer and radioprotector agents. In this context, the radiomodulatory properties exerted by an aqueous extract from the fruits of the Italian Prunus avium cv. Della Recca (PaDRw) were investigated. The extract, obtained through an environmentally-friendly ultrasound-assisted extraction, seemed to act as a radioprotector at lower tested doses (25 and 50 µg mL-1) and a radiosensitizer at 400 and 500 µg mL-1 dose levels towards the neuroblastoma SH-SY5Y cell line, irradiated with four graded X-ray doses (0, 0.5, 2, and 4 Gy). The fractionation of PaDRw by Amberlite XAD-4 non-ionic polymeric resin, coupled to LC-UV-MS/MS techniques, proved to be efficient also in the disclosure of lower constituents. About 63% of the whole PaDRw extract was constituted of hexitol, followed by fructose (â¼22.8%) and glucose (â¼10.7%). Chlorogenic acids and flavonoids, which accounted only for â¼2.2%, were hypothesized to be the main actors in PaDRw-induced radiomodulation.
