Editorial: The role of medicinal plants and natural products in modulating oxidative stress and inflammatory related disorders

© 2022 The Authors. Published by Frontiers Media. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.3389/fphar.2022.957296Published versio

Inhibition of platelet aggregation by olive oil phenols via cAMP-phosphodiesterase

The aim of the present study was to confirm that olive oil phenols reduce human platelet aggregability and to verify the hypothesis that cAMP- and cGMP- phosphodiesterases (PDE) could be one of the targets of the biological effect. Four extracts from oils characterized by a high phenol content (HPE), and low phenol levels (LPE) were prepared and analyzed quali- and quantitatively by HPLC-UV and electrospray ionization–MS/MS. Human washed platelets stimulated with thrombin were used for the aggregation assay. Human platelet cAMP-PDE and recombinant PDE5A1 were used as enzyme source. Platelet aggregation and enzyme activity were assayed in the presence of HPE, LPE and individual phenols. The phenol content of HPE ranged between 250 and 500 mg/kg, whereas the LPE content was 46 mg/kg. The compounds identified were hydroxytyrosol (HT), tyrosol (TY), oleuropein aglycone (OleA) and the flavonoids quercetin (QU), luteolin (LU) and apigenin (AP). OleA was the most abundant phenol (range 23·3 to 37·7 %) and LU was the most abundant flavonoid in the extracts. Oil extracts inhibited platelet aggregation with an 50% inhibitory concentration interval of 1·23–11·2 μg/ml. The inhibitory effect of individual compounds (10 μm) including homovanillyl alcohol (HVA) followed this order: OleA>LU>HT = TY = QU = HVA, while AP was inactive. All the extracts inhibited cAMP-PDE, while no significant inhibition of PDE5A1 (50μg/ml) was observed. All the flavonoids and OleA inhibited cAMP-PDE, whereas HT, TY, HVA (100 μm) were inactive. Olive oil extracts and part of its phenolic constituents inhibit platelet aggregation; cAMP-PDE inhibition is one mechanism through which olive oil phenols inhibit platelet aggregation

A validated LC–MS/MS method for quantitative determination of L-dopa in Fagioli di Sarconi beans (Phaseolus vulgaris L.)

An analytical method based on ultrasound assisted extraction (UAE) and liquid chromatography 36 coupled to electrospray tandem mass spectrometry (LC–ESI/MS/MS) was validated and applied for 37 determining L-dopa in four ecotypes of Fagioli di Sarconi beans (Phaseolus vulgaris L.), marked 38 with the European label PGI (Protected Geographical Indication). The selectivity of the proposed 39 method was ensured by the specific fragmentation of the analyte. Simple isocratic chromatographic 40 conditions and mass spectrometric detection in multiple reaction monitoring (MRM) acquisition 41 mode were used for sensitive quantification. The LC–ESI/MS/MS method was validated within a 42 linear range of 0.001–5.000 μg/mL. Values of 0.4 and 1.1 ng/mL were obtained for limit of detection 43 and limit of quantification, respectively. The repeatability, inter-day precision and recovery values 44 ranges were 0.6-4.5%, 5.4-9.9%, 83-93 %, respectively. Fresh and dried beans cultivated exclusively 45 with organic methods avoiding any synthetic fertilizers and pesticides, as well as pods, were analyzed 46 showing a L-dopa content ranging from 0.020±0.005 μg/g to 2.34±0.05 μg/g dry weight

Ellagitannins of the fruit rind of pomegranate (Punica granatum) antagonize in vitro the host inflammatory response mechanisms involved in the onset of malaria

<p>Abstract</p> <p>Background</p> <p>The sun-dried rind of the immature fruit of pomegranate (<it>Punica granatum</it>) is presently used as a herbal formulation (OMARIA, Orissa Malaria Research Indigenous Attempt) in Orissa, India, for the therapy and prophylaxis of malaria. The pathogenesis of cerebral malaria, a complication of the infection by <it>Plasmodium falciparum</it>, is an inflammatory cytokine-driven disease associated to an up-regulation and activity of metalloproteinase-9 and to the increase of TNF production. The <it>in vitro </it>anti-plasmodial activity of <it>Punica granatum (Pg) </it>was recently described. The aim of the present study was to explore whether the anti-malarial effect of OMARIA could also be sustained via other mechanisms among those associated to the host immune response.</p> <p>Methods</p> <p>From the methanolic extract of the fruit rind, a fraction enriched in tannins (<it>Pg</it>-FET) was prepared. MMP-9 secretion and expression were evaluated in THP-1 cells stimulated with haemozoin or TNF. The assays were conducted in the presence of the <it>Pg</it>-FET and its chemical constituents ellagic acid and punicalagin. The effect of urolithins, the ellagitannin metabolites formed by human intestinal microflora, was also investigated.</p> <p>Results</p> <p><it>Pg</it>-FET and its constituents inhibited the secretion of MMP-9 induced by haemozoin or TNF. The effect occurred at transcriptional level since MMP-9 mRNA levels were lower in the presence of the tested compounds. Urolithins as well inhibited MMP-9 secretion and expression. <it>Pg</it>-FET and pure compounds also inhibited MMP-9 promoter activity and NF-kB-driven transcription.</p> <p>Conclusions</p> <p>The beneficial effect of the fruit rind of <it>Punica granatum </it>for the treatment of malarial disease may be attributed to the anti-parasitic activity and the inhibition of the pro-inflammatory mechanisms involved in the onset of cerebral malaria.</p

Phenolic profile and antioxidant activity of different raisin (Vitis vinifera L.) samples

In the last years, the interest in non-alcoholic grape products, aa potential alternative sources of phenolic compounds, has considerably increased. Raisins are dried grapes largely consumed in the Mediterranean area for the positive pattern of nutrients, and for recent data describing potential benefits on human health. Among the health-promoting substances contained in raisins, flavonoids seem the most interesting. The aim of this study was the application of in vitromethods for the characterization of the phenolic fraction of five samples of raisins, and, in parallel, the evaluation of their antioxidant activity. The methods were: 1) Folin-Cocalteau's assay for the quantification of total polyphenol content; 2) vanillin assay for the measure of flavan-3-ols content; 3) DPPH (1,1,-diphenil-2\u2014picrylhydrazyl) spectrophotometric assay for the assessment of radical scavenging activity; 4) High Performance Thin Layer Chromatography for separation of phenolic substances and assessment of their antioxidant activity; 5) chromatographic separation and quantification of main active substances was performed by HPLC-DAD. Although raisins showed a high variability in their composition, they can be considered as a promising source of phenolic compounds with a significant antioxidant activity for the human diet

In vitro studies on the mechanism of action of two compounds with antiplasmodial activity: ellagic acid and 3,4,5-Trimethoxyphenyl(6?-O-Galloyl)-β-D-glucopyranoside

To investigate the mechanism of action of two antiplasmodial compounds, ellagic acid and 3,4,5-trimethoxyphenyl (6′-O-galloyl)-β-D-glucopyranoside (TMPGG), we studied in vitro two metabolic reactions of intraerythrocytic parasites: the activity of recombinant plasmepsin II, one of the haemoglobin proteases, and the detoxification of haematin into β-haematin. Both compounds inhibited plasmepsin II activity, but at concentrations ten-fold higher than those needed for inhibiting parasite growth. Moreover, ellagic acid inhibited the formation of β-haematin, with an IC50 only 3-fold higher than that of chloroquine. These data suggest that the antiplasmodial activity of ellagic acid could be related to the inhibition of β-haematin formation, whereas plasmepsin II does not represent the main target of the two compounds

Fruit quality of Italian pomegranate (Punica granatum L.) autochthonous varieties

Pomegranate is getting an increasing attention for its health-promoting effects. Collection and characterization of plants of local sources has been performed, and five accessions have been propagated and cultivated in a collection field for extra situ investigations. Accessions differ for pomological traits and chemical composition. Three of them, MG1, MG2, and MG3, belong to typology with low-medium acidity and high sugar content, while the other two, Tordimonte A and B, belong to typology with high acidity. In the juice and in the peels’ extract of Tordimonte A accession a high level of punicalin has been found through chromatographic determinations, while the presence of punicalagin was found in the juice of accession MG1. The accessions MG1, MG2, and MG3 seem particularly suitable for direct commercialization of fruits due to the fruit traits and quality (sweet varieties), while Tordimonte A and B could be valuable for juice processing (sour varieties).L'articolo è disponibile sul sito dell'editore http://www.springerlink.co

Phenolic profile and antioxidant activity of different raisin (Vitis vinifera L.) samples

In the last years, the interest in non-alcoholic grape products, aa potential alternative sources of phenolic compounds, has considerably increased. Raisins are dried grapes largely consumed in the Mediterranean area for the positive pattern of nutrients, and for recent data describing potential benefits on human health. Among the health-promoting substances contained in raisins, flavonoids seem the most interesting. The aim of this study was the application of in vitromethods for the characterization of the phenolic fraction of five samples of raisins, and, in parallel, the evaluation of their antioxidant activity. The methods were: 1) Folin-Cocalteau's assay for the quantification of total polyphenol content; 2) vanillin assay for the measure of flavan-3-ols content; 3) DPPH (1,1,-diphenil-2—picrylhydrazyl) spectrophotometric assay for the assessment of radical scavenging activity; 4) High Performance Thin Layer Chromatography for separation of phenolic substances and assessment of their antioxidant activity; 5) chromatographic separation and quantification of main active substances was performed by HPLC-DAD. Although raisins showed a high variability in their composition, they can be considered as a promising source of phenolic compounds with a significant antioxidant activity for the human diet