Polyphenols and Maillard Reaction Products in Dried Prunus spinosa Fruits: Quality Aspects and Contribution to Anti-Inflammatory and Antioxidant Activity in Human Immune Cells Ex Vivo

Abstract

Dried Prunus spinosa fruits (sloes) are folk phytotherapeutics applied to treat chronic inflammatory disorders. However, their pharmacological potential, activity vectors, and drying-related changes in bioactive components remain unexplored. Therefore, the present research aimed to evaluate the anti-inflammatory and antioxidant effects of dried sloes in ex vivo models of human neutrophils and peripheral blood mononuclear cells (PMBCs) and establish their main active components. It was revealed that the fruit extracts significantly and dose-dependently inhibited the respiratory burst, downregulated the production of elastase (ELA-2) and TNF-α, and upregulated the IL-10 secretion by immune cells under pro-inflammatory and pro-oxidant stimulation. The slightly reduced IL-6 and IL-8 secretion was also observed. The structural identification of active compounds, including 45 phenolics and three Maillard reaction products (MRPs) which were formed during drying, was performed by an integrated approach combining LC-MS/MS, preparative HPLC isolation, and NMR studies. The cellular tests of four isolated model compounds (chlorogenic acid, quercetin, procyanidin B2, and 5-hydroxymethylfurfural), supported by statistical correlation studies, revealed a significant polyphenolic contribution and a slight impact of MRPs on the extracts’ effects. Moreover, a substantial synergy was observed for phenolic acids, flavonoids, condensed proanthocyanidins, and MPRs. These results might support the phytotherapeutic use of dried P. spinosa fruits to relieve inflammation and establish the quality control procedure for the extracts prepared thereof.

Valorisation of the Inhibitory Potential of Fresh and Dried Fruit Extracts of Prunus spinosa L. towards Carbohydrate Hydrolysing Enzymes, Protein Glycation, Multiple Oxidants and Oxidative Stress-Induced Changes in Human Plasma Constituents

“…Although the ethnopharmacological sources suggested the potential of blackthorn fruits in the prophylaxis and therapy of DM and its cardiovascular pathologies [ 8 , 9 , 10 ], the relevant activity mechanisms and vectors are still insufficiently recognised. Most of the earlier works focused on the anti-inflammatory properties of the fruit preparations: the extracts were proved to downregulate the pro-inflammatory response of human immune cells, including neutrophils and peripheral blood mononuclear cells [ 11 , 12 ], and inhibit the expression of adhesion molecules in human endothelial cells [ 13 ], which might be essential for alleviating the DM-associated vascular inflammation. The potential direct antidiabetic properties of sloe fruits have been analysed to date only by Popović et al [ 14 ].…”

The favorable impacts of silibinin polyphenols as adjunctive therapy in reducing the complications of COVID-19: A review of research evidence and underlying mechanisms

“…The present computational approach was found helpful to predict the best possible inhibitor of protease and may result in an effective therapeutic agent against COVID-19. In vitro Speciale, Muscarà, Molonia, Cimino, Saija, Giofrè [19] HUVECs 5,10 and 25 µg/ml silibinin reduced TNF-α-induced gene expression of the proinflammatory genes IL-6 and MCP-1, as well as of PAI-1, a critical factor in coagulopathy and thrombosis, and of ET-1, a peptide involved in hemostatic vasoconstriction. Then, due to endothelium anti-inflammatory and anticoagulant properties of silibinin and its capability to interact with SARS-CoV-2 main target proteins demonstrated herein, silibinin could be a strong candidate for COVID-19 management from a multitarget perspective.…”

“…Consequently, they might play a protective role against COVID-19-associated complications [18] . In this regard, polyphenol and flavonoid compounds' anti-inflammatory and antioxidant activity have been confirmed strongly [19] , [20] . Silymarin is a complex polyphenolic compound derived from the seed of the milk thistle plant, and it is known for its anti-inflammatory, antiviral, anti-oxidative, and immunomodulatory effects [21] , [22] , [23] .…”

Phenolic Composition, Antioxidant, Anti-Enzymatic, Antimicrobial and Prebiotic Properties of Prunus spinosa L. Fruits

“…For the PSE2, the methanol extract had higher contents of these phenols than hydroethanolic and water extracts. It was previously reported that 3-caffeoylquinic acid contents in hydromethanolic extracts of blackthorn fruits originating from Poland were 452 and 1556 mg/100 g [ 13 , 18 ]. Although a comparison with our results is not possible due to the differently expressed results, 3-caffeoylquinic acid contents varied in dried blackthorn fruits in northern Serbia, from 46.63 to 636.14 mg/100 g, depending on the location and genotype [ 10 ].…”

“…In fact, freeze-drying is the most favorable preservation method compared to convection drying and frozen [ 17 ]. However, dried blackthorn fruits, which are characterized by a much lower content of bioactive compounds than fresh fruits, exhibited considerable anti-inflammatory and antioxidant potentials [ 18 ]. Therefore, blackthorn fruits are gaining attention not only as “undiscovered” health-promoting food but also as a potential source of pigments, flavors, and bioactive ingredients for functional food and nutraceutical applications [ 8 , 19 ].…”