Flower extracts of Prunus spinosa L. (blackthorn)– a traditional medicinal plant of Central and Eastern Europe indicated for the treatment of urinary tract disorders, inflammation, and adjunctive therapy of cardiovascular diseases– were evaluated in terms of chemical composition, antioxidant activity, potential anti-inflammatory effects, and cellular safety in function of fractionated extraction. The UHPLC-PDA-ESI-MS3 fingerprinting led to full or partial identification of 57 marker constituents (36 new for the flowers), mostly flavonoids, A-type proanthocyanidins, and phenolic acids, and provided the basis for authentication and standardization of the flower extracts. With the contents up to 584.07 mg/g dry weight (dw), 490.63 mg/g dw, 109.43 mg/g dw, and 66.77 mg/g dw of total phenolics (TPC), flavonoids, proanthocyanidins, and phenolic acids, respectively, the extracts were proven to be rich sources of polyphenols. In chemical in vitro tests of antioxidant (DPPH, FRAP, TBARS) and enzyme (lipoxygenase and hyaluronidase) inhibitory activity, the extracts effects were profound, dose-, phenolic-, and extraction solvent-dependent. Moreover, at in vivo-relevant levels (1-5 µg/mL) the extracts effectively protected the human plasma components against peroxynitrite-induced damage (reduced the levels of oxidative stress biomarkers: 3-nitrotyrosine, lipid hydroperoxides, and thiobarbituric acid-reactive substances) and enhanced the total antioxidant status of plasma. The effects observed in biological models were in general dose- and TPC-dependent; only for protein nitration the relationships were not significant. Furthermore, in cytotoxicity tests, the extracts did not affect the viability of human peripheral blood mononuclear cells (PBMC), and might be regarded as safe. Among extracts, the defatted methanol-water (7:3, v/v) extract and its diethyl ether and ethyl acetate fractions appear to be the most advantageous for biological applications. As compared to the positive controls, activity of the extracts was favorable, which might be attributed to some synergic effects of their constituents. In conclusion, this research proves that the antioxidant and enzyme inhibitory capacity of phenolic fractions should be counted as one of the mechanisms behind the activity of the flowers reported by traditional medicine and demonstrates the potential of the extracts as alternative ingredients for functional products supporting the treatment of oxidative stress-related pathologies cross-linked with inflammatory changes, especially in cardiovascular protection.

Sorbus domestica leaves are a traditionally used herbal medicine recommended for the treatment of oxidative stress-related diseases. Dry leaf extracts (standardized by LC-MS/MS and LC-PDA) and nine model activity markers (polyphenols), were tested in scavenging assays towards six in vivo-relevant oxidants (O₂^•−, OH^•, NO^•, H₂O₂, ONOO⁻, HClO). Ascorbic acid (AA) and Trolox (TX) were used as positive standards. The most active extracts were the diethyl ether and ethyl acetate fractions with activities in the range of 3.61–20.03 µmol AA equivalents/mg, depending on the assay. Among the model compounds, flavonoids were especially effective in OH^• scavenging, while flavan-3-ols were superior in O₂^•− quenching. The most active constituents were quercetin, (−)-epicatechin, procyanidins B2 and C1 (3.94–24.16 µmol AA/mg), but considering their content in the extracts, isoquercitrin, (−)-epicatechin and chlorogenic acid were indicated as having the greatest influence on extract activity. The analysis of the synergistic effects between those three compounds in an O₂^•− scavenging assay demonstrated that the combination of chlorogenic acid and isoquercitrin exerts the greatest influence. The results indicate that the extracts possess a strong and broad spectrum of antioxidant capacity and that their complex composition plays a key role, with various constituents acting complementarily and synergistically.

Broccoli sprouts represent a health-promoting food, rich in antioxidant and anti-inflammatory phytochemicals, among which sulfur compounds are most extensively investigated. In this study, the phenolics of broccoli sprouts (Brassica oleracea var. italica ‘Cezar’) were examined for variability during germination and influence on the bioactivity of sprouts. In the sprouts germinated in darkness, 31 compounds were identified by UHPLC-PDA-ESI-MS³ (18 sinapic acid derivatives, 8 glucosinolates, and 5 flavonoids) with sinapoyl components (SADs) prevailing among polyphenols. The total SADs decreased during germination (down to 4.85 mg per g dw in 6-day-sprouts), but the concurrent changes in molecular structures of the leading compounds (sinapine was replaced by sinapate sugar esters and sinapic acid) increased the antioxidant capacity of the sprouts. The glucosinolate-depleted 6-day-sprout extract (34.2 mg SADs per g dw) effectively protected human plasma components against peroxynitrite-induced oxidative damage in vitro (reduced the levels of 3-nitrotyrosine, lipid hydroperoxides and thiobarbituric acid-reactive substances) and enhanced the non-enzymatic antioxidant status of plasma. It also downregulated the release of pro-inflammatory cytokines (TNF-α, IL-6) from LPS-stimulated human peripheral blood mononuclear cells and increased the production of IL-10, an anti-inflammatory mediator. The relevant activity parameters of sinapic acid indicated that SADs might be linked to the observed effects. The results support the application of broccoli sprouts in oxidative stress- and inflammation-related diseases and the role of SADs as their bioactive components next to glucosinolates.

The phytochemical profile and anti-inflammatory activity of Gaultheria procumbens dry lipophilic leaf extracts were evaluated. Forty compounds were identified by GC-MS, representing 86.36% and 81.97% of the petroleum ether (PE) and chloroform (CHE) extracts, respectively, with ursolic acid (28.82%), oleanolic acid (10.11%), methyl benzoate (10.03%), and methyl salicylate (6.88%) dominating in CHE, and methyl benzoate (21.59%), docosane (18.86%), and octacosane (11.72%) prevailing in PE. Three components of CHE were fully identified after flash chromatography isolation and spectroscopic studies as (6S,9R)-vomifoliol (4.35%), 8-demethyl-latifolin (1.13%), and 8-demethylsideroxylin (2.25%). Hyaluronidase and lipoxygenase inhibitory activity was tested for CHE (IC50 = 282.15 ± 10.38 μg/mL and 899.97 ± 31.17 μg/mL, respectively), PE (IC50 = 401.82 ± 16.12 μg/mL and 738.49 ± 15.92 μg/mL), and nine of the main constituents versus heparin (IC50 = 366.24 ± 14.72 μg/mL) and indomethacin (IC50 = 92.60 ± 3.71 μg/mL) as positive controls. With the best activity/concentration relationships, ursolic and oleanolic acids were recommended as analytical markers for the extracts and plant material. Seasonal variation of both markers following foliar development was investigated by UHPLC-PDA. The highest levels of ursolic (5.36–5.87 mg/g DW of the leaves) and oleanolic (1.14–1.26 mg/g DW) acids were observed between August and October, indicating the optimal season for harvesting.