Juglans regia L., walnut, is a large, long-living tree, cultivated in temperate climates around the world. It is highly appreciated for its nutritional kernels and high-quality timber. Its barks, leaves, and husk are used as dyes and in folk medicine as herbal remedies for several diseases. From a biological and chemical standpoint, relatively little is known about the male flowers of the tree. Therefore, the aim of the study was to evaluate the phenolic profile as well as in vitro antioxidant, antimicrobial, and antiproliferative activity of male Juglans regia L. flowers. Phenolic content was determined by UPLC/PDA/MS/MS analyses; antioxidant activity was assessed by five different methods; antimicrobial activity was evaluated against the six most common pathogenic strains of Gram-positive and Gram-negative bacteria, and antiproliferative properties were assessed against six cell lines. Most of the analyses carried out in this study were performed for the first time for this raw material. J. regia flower extract was characterized by a strong ability to scavenge DPPH˙ free radicals, hydroxyl radicals, and chelating metal ions. Among the examined bacterial strains and neoplastic lines, the strongest antimicrobial activity was shown against S. aureus, L. monocytogenes, and B. cereus, and cytotoxic activity against breast cancer, glioblastoma, and astrocytoma cells. Male J. regia flowers have also been found to be a rich source of phenolic compounds. The content of polyphenols in the extract was 4369.73 mg/100 g d.w., and 24 compounds from the group of flavonoids, phenolic acids, and juglunosides were identified. Additionally, a strong correlation between the content of polyphenols and the antioxidant capacity and cytotoxic activity was observed. This is why the tested J. regia flowers are an excellent source of effective natural antioxidant, antibacterial, and chemopreventive compounds that have potential to be used in the pharmaceutical or food industries.

The aim of this study was to assess the biological potential of the polyphenolic fraction isolated from J. regia leaves, collected in the Subcarpathian region (Poland). The phenolic profile was determined using the UPLC-PDA-MS/MS method. Biological activity was determined by evaluating the antioxidant, anticancer, antibacterial, and antifungal effects. Prior to this study, the purified polyphenolic fraction was not been tested in this regard. A total of 40 phenolic compounds (104.28 mg/g dw) were identified, with quercetin 3-O-glucoside and quercetin pentosides dominating. The preparation was characterized by a high ability to chelate iron ions and capture O₂^•− and OH^• radicals (reaching IC₅₀ values of 388.61, 67.78 and 193.29 µg/mL, respectively). As for the anticancer activity, among the six tested cell lines, the preparation reduced the viability of the DLD-1, Caco-2, and MCF-7 lines the most, while in the antibacterial activity, among the seven tested strains, the highest susceptibility has been demonstrated against K. pneumoniae, S. pyogenes, and S. aureus. Depending on the needs, such a preparation can be widely used in the design of functional food and/or the cosmetics industry.

Increasing interest in new sources of secondary metabolites as biologically active substances has resulted in an advanced study of many plant species. Loquat (Eriobotrya japonica (Thunb.) Lindl. = Rhaphiolepis bibas (Lour.) Galasso & Banfi, Rosaceae family), an evergreen, subtropical fruit tree, native to China and Japan, but cultivated in southern countries of Europe, is a species commonly used in folk medicine and may be an excellent source of bioactive compounds. Therefore, the aim of the present study was to evaluate the profile of the phenolic constituents of E. japonica fruits and leaves originating from Tuscany (Italy), as well as their in vitro antioxidant and chemopreventive activities on human cancer cell lines breast adenocarcinoma (MCF-7), colon adenocarcinoma (Caco-2 and HT-29), and glioblastoma (U87MG). Results revealed that the extract of leaves displayed higher antioxidant and anticancer potential than the fruit extract and contained 25 individual phenolic compounds that have been characterized and quantified by the UPLC-PDA-MS method. The antiproliferative activity was correlated with the content of polyphenolic compounds indicating that both fruits and leaves are a good source of antioxidants and may be exploited as nutraceuticals enriching food or as components for the cosmetic/pharmaceutical industry.

Pollen is one of the major by-products of the walnut tree, yet it is poorly investigated. Thus, the aim of this study was to investigate the total phenolics, flavonoids, antioxidant, anticancer potential, and polyphenol profile of pollen obtained from male Juglans regia flowers. A total of 24 phenolic compounds were identified in Juglans regia pollen and all of them were reported for the first time for this raw material. The content of polyphenols was 408.03 mg/100 g dry weight (dw) and the most abundant components were quercetin 3-O-sophoroside and 4′,5,7-trihydroxy-3,6-dimethoxyflavone-7-O-beta-D-glucoside. The concentration of these compounds, as well as the total content of polyphenols and flavonoids, strongly determined the antioxidant and cytotoxic activity of Juglans regia pollen. Antioxidant action using the ABTS and CUPRAC methods had the values of 3.35 and 0.32 mmol TE/g dw, respectively. In turn, in the tests of chelating ability of ferrous ion, O₂^•− and OH⁻ radical scavenging activity, of which the results were expressed as IC₅₀, the values were equal to 335.01, 459.31, and 92.89 µg/mL, respectively. Among the six cancer cell lines, the strongest effect was demonstrated for Caco-2 (140.65 µg/mL) and MCF-7 (140.98 µg/mL) cells. The results provide valuable and previously unpublished data on the polyphenol composition and biological potential of Juglans regia pollen.

The aim of the study was to design microcapsules with a core of blueberry fruit extracts (Vaccinium myrtillus L.) using the ionotropic gelation method and then assess the effect of the type of extracts used and the combination of polymers on the profile of phenolic compounds, their in vitro bioavailability, stability during storage, as well as their antioxidant characteristics and cytotoxic activity against colon cancer cells while assessing biocompatibility against normal colon epithelial cells. Encapsulation efficiency (EE), ranging from 8.79 to 74.55%, significantly depended on the extract used and the type of carrier. It was shown that the addition of pectin (Pect) and whey protein isolate (WPI) to alginate (Alg) improved the efficiency of the encapsulation process. For this version of microcapsules, the highest antioxidant activity, phenolic compound content and their stability during storage were also demonstrated. The estimated content of phenolic compounds ranged from 0.48 to 40.07 mg/g, and the dominant compound was cyanidin 3-O-glucoside. In turn, the highest bioavailability of these compounds and the highest cytotoxic activity against cancer cells were characterized by microcapsules with Alg and WPI. Nevertheless, good biocompatibility with normal colon epithelial cells was demonstrated for all versions of microcapsules. The obtained data indicate that the tested variants of microcapsules protect the bioactive compounds of blueberry fruit extracts, which translates into maintaining their health-promoting properties.

The aim of this study is to assess the effect of adding dried and ground walnut male flowers to wheat flour on selected physicochemical and antioxidant properties of the obtained wheat bread. The control sample was bread without the addition of walnut male flowers. In the tests, the addition of flowers was used in the amounts of 0.5%, 1.0%, 1.5%, 2.0% and 2.5% of the weight of the flour used in the control sample. Bread dough was prepared according to the direct method with the use of yeast. The parameters of the baking process of the control bread and of the test bread were calculated. The selected parameters determining the quality of the obtained bread, including the loaf volume, the specific volume, the crumb porosity, the crumb texture and the color were measured. The antioxidant potential and total polyphenol content were tested both in the dough and in the bread. The test results were analyzed statistically. It was found that the partial replacement of wheat flour with walnut male flowers resulted in a significant reduction in the loaves’ volume and in the darkening of both the color of the dough and the crumb. The value of the L* parameter decreased with the increasing addition of walnut flowers. The lowest values of this parameter were found to be 53.87 (crust) and 39.94 (crumb) in the sample with 2.5% addition. The average volume of the loaves ranged from 565 cm³ (0.5%) to 675 cm³ (control). The use of the additive in the amount of 2.5% caused significant changes in the values of most of the examined parameters of the bread crumb texture. The addition of walnut male flowers to the flour had a significant effect on the antioxidant potential and the total polyphenol content of the tested doughs and breads. In the case of bread, the total polyphenol content value ranged from 96.90 mg GAE/g dw to 208.08 mg GAE/g dw. Similarly, the antioxidant potential increased with increasing walnut male flower supplementation. The antioxidant potential determined by the ABTS and FRAP methods ranged from 1.42 mmol TE/g dw to 2.02 mmol TE/g dw and from 0.08 mmol TE/g dw to 0.33 mmol TE/g dw, respectively. The obtained research results prove the application potential of walnut flowers in the design of food, with beneficial pro-health properties, and are an example of the use of plant by-products in the process of food enrichment.