Polyphenol-Enriched Extracts of Prunus spinosa Fruits: Anti-Inflammatory and Antioxidant Effects in Human Immune Cells Ex Vivo in Relation to Phytochemical Profile

Abstract

The fresh fruits of Prunus spinosa L., a wild plum species, are traditionally used for dietary purposes and medicinal applications in disorders related to inflammation and oxidative stress. This study aimed to investigate the phytochemical composition of the fruits in the function of fractionated extraction and evaluate the biological potential of the extracts as functional products in two models of human immune cells ex vivo. Fifty-seven phenolic components were identified in the extracts by UHPLC-PDA-ESI-MS3, including twenty-eight new for the analysed fruits. Fractionation enabled the enrichment of polyphenols in the extracts up to 126.5 mg gallic acid equivalents/g dw total contents, 91.3 mg/g phenolic acids (caffeoyl-, coumaroyl-, and feruloylquinic acids), 41.1 mg/g flavonoids (mostly quercetin mono-, di- and triglycosides), 44.5 mg/g condensed proanthocyanidins, and 9.2 mg/g anthocyanins (cyanidin and peonidin glycosides). The hydroalcoholic extract and phenolic-enriched fractions of the fruits revealed significant ability to modulate pro-oxidant, pro-inflammatory, and anti-inflammatory functions of human neutrophils and peripheral blood mononuclear cells (PBMCs): they strongly downregulated the release of reactive oxygen species, TNF-α, and neutrophils elastase, upregulated the secretion of IL-10, and slightly inhibited the production of IL-8 and IL-6 in the cells stimulated by fMLP, fMLP+cytochalasin B, and LPS, depending on the test. Correlation studies and experiments on the pure compounds indicated a significant contribution of polyphenols to these effects. Moreover, cellular safety was confirmed for the extracts by flow cytometry in a wide range of concentrations. The results support the traditional use of fresh blackthorn fruits in inflammatory disorders and indicate extracts that are most promising for functional applications.

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

“…As P. spinosa dried fruits are primarily used as a traditional herbal remedy [ 3 , 4 , 5 ], for the present study, the fresh fruits were dried in the typical conditions of herbal medicinal products [ 27 ]. The same fresh plant material batch and the same extraction procedure as in our previous work on fresh fruits [ 13 ] were used for direct result comparison. In the first step, the dried fruits were extracted with methanol-water (75:25, v / v ) to maximise recovery of polyphenols [ 13 ] and reflect the composition of tinctures, the most popular medicinal preparations of dried sloes [ 3 , 4 , 5 ].…”

“…Although ethnopharmacological sources do not differentiate the application range of fresh and dried sloes, to date scientific interest has focused almost exclusively on fresh fruits [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ], and information on the dried P. spinosa plums is extremely scarce [ 15 , 16 , 17 ]. On the other hand, fresh sloes have been relatively deeply studied, primarily in terms of the mechanisms of their anti-inflammatory and antioxidant effects.…”

“…In our previous study, we have documented that the fresh fruit extracts significantly modulate the functions of human immune cells, neutrophils and peripheral blood mononuclear cells (PBMCs) involved in the pathogenesis of inflammation. They downregulate the secretion of reactive oxygen species (ROS), pro-inflammatory cytokines (tumour necrosis factor α, TNF-α) and enzymes (elastase, ELA-2), and stimulate the production of the anti-inflammatory cytokine IL-10 [ 13 ]. Moreover, according to Sabatini et al [ 14 ], the alcoholic extracts of fresh sloe plums can decrease the expression of IL-6 and adhesion molecules ICAM-1 and VCAM-1 in human endothelial cells (HUVEC).…”

“…The accumulated research suggests that the main active components of fresh sloes are polyphenols. A rich fraction of various polyphenols with more than 50 individual compounds has been revealed in the fresh plant material, including condensed proanthocyanidins, phenolic acids, anthocyanins, and flavonols [ 13 ]. It is known that the biological activity of fruit polyphenolic fractions depends on the presence of specific individual compounds and their proportions [ 18 ].…”

“…Extraction of a fruit matrix is crucial in developing fruit-based medicines and functional products [ 26 ]. The fractionated extraction enables the concentration of the active plant components and facilitates their identification through selective isolation and comparative activity studies [ 13 , 18 ].…”