A high-performance liquid chromatographic method with gradient elution and diode-array detection was developed to quantify free phenolic acids (gallic, vanillic, chlorogenic, caffeic, syringic, p-coumaric, ferulic, sinapic, salycilic, elagic and trans-cinnamic), flavonoids (catechin, epicatechin, rutin, myricetin and quercetin) and juglone in walnut leaves. Chromatographic separation was performed on a Hypersil Gold C18 column (5 µm particle size, 250 × 4.6 mm) and detection was conducted at three different wavelengths (254, 278 and 300 nm) according to the absorption maxima of the analyzed compounds. Validation procedures were conducted and the method was proven to be precise, accurate and sensitive. The developed method has been applied to analyze walnut leaves samples from nine different cultivars, with the same agricultural, geographical and climatic conditions. The experimental results revealed high concentrations of myricetin, catechin hydrate and rutin, and low concentrations of quercetin and epicatechin aglycones. Ellagic acid was established as the dominating phenolic acid of walnut leaves, followed by trans-cinnamic, chlorogenic and caffeic acids. Juglone content varied between 44.55 and 205.12 mg/100 g fresh weight. Significant differences were detected among cultivars for the concentration levels of phenolics.

In this study, the total phenolic, total flavonoids, phenolic compounds, the mineral content, and antioxidant activity of fruit extracts of seven wild species (Crataegus monogyna Jacq., Prunus spinosa L., Rosa canina L., Hippophaë rhamnoides L., Rubus fruticosus L., Prunus padus, Cornus mas L.) were investigated. The results indicated significant differences (p < 0.05) in the total phenolics and total flavonoids content, between the seven analyzed species. These ranged from 184.69 to 727.29 mg GAE/100 g FW and 17.27 to -165.55 mg QE/100 g FW, respectively. The antioxidant activity found in fruits was not directly affected by the total phenolic content (TPC). This activity was linked to a larger extent to the type of individual phenolic compounds and to a lesser extent to the TPC, because fruits with higher TPC have not always presented the highest values of antioxidant activity. HPLC analysis of methanolic extract showed the presence of phenolic acids trans-cinnamic) and flavonoids (i.e. catechin, epicatechin, rutin, myricetin, and quercetin). Significant differences (p < 0.05) were observed in each individual mineral between fruits from wild flora. The fruits tissues of wild species turned out to be a good source of calcium (Ca), magnesium (Mg), sodium (Na), iron (Fe), manganese (Mn), copper (Cu), chromium (Cr), zinc (Zn), and boron (B). The results demonstrated that wild species possessed great potential for food production as sources of bioactive compounds such as phenolic compounds and minerals, for food supplements or functional foods. ARTICLE HISTORY

Context: Walnut [Juglans regia L. (Juglandaceae)] is a rich source of phenolic compounds, including phenolic acids, naphtoquinones and flavonoids. The increasing interest in the powerful biological activities of plant phenolics has outlined the necessity of determining their content in leaves of different walnut cultivars.

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In the present work, four of the most widely used culinary herbs (parsley, dill, lovage and celery leaves) in the Romanian traditional cuisine were assessed for some nutritional quality parameters (moisture content, titratable acidity, ascorbic acid content and mineral content), total phenolics content, total flavonoids content and antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. In addition, high-performance liquid chromatography (HPLC) coupled with diode-array detection was applied for the identification and quantification of some individual phenolic compounds in the selected aromatic herbs. Although parsley showed the highest ascorbic acid content (206.32 mg/100 g fw), it registered the lowest antioxidant activity. Fresh lovage recorded the highest total phenolic content (577.04 mg GAE/100 g), total flavonoids content (298.38 mg QE/100 g) and antioxidant activity, followed by dill and celery leaves. Among the identified phenolic acids, ellagic acid was predominant in lovage and celery leaves whereas sinapic and vanillic acids were prevalent in dill. Among flavonoids, myricetin was predominant in parsley and celery leaves whereas rutin was predominant in dill and lovage.

Juglone (5-hydroxy-1,4-napthoquinone) is a chemical compound released by walnut trees that can be toxic for surrounding plant species. In the present study, juglone was identified in leaves and green husk in five walnut cultivars: 'Germisara' , 'Jupanesti' , 'Franquette' , 'Vina' , 'Valcor' by using high performance liquid chromatography (HPLC-RP). Juglone was found predominant in green husk (average value of cultivars is about 31.308 mg/100 g). Significant differences in contents of identified juglone were observed among cultivars that ranged from 20.56 to 42.78 mg/100g for green husk, and 5.42 to 22.82 mg/100 g for leaves. It was also found that walnut green husk and leaves represent the most important source of walnut phenolics.

Total phenolic, total flavonoid distribution and antioxidant activity in skin, pulp and fruit extracts of 12 plum cultivars were investigated. The results showed that the levels of total phenolic and flavonoid compounds changed depending on cultivars and fruit parts. The total phenolic content in skin was 4.5 times higher than that in pulp and 3.2 times higher than that in the whole fruit. The total flavonoid content in skin was 18.7 times higher than that in pulp and 9.6 times higher than that in the whole fruit. As the trend observed for antioxidant activity, a positive relationship (correlation coefficient r 2 = 0.83-0.92) was presented between total phenolics and total antioxidant capacity. The results confirm that plum is a good source of natural phenolic antioxidants. PRACTICAL APPLICATIONSThe present study indicated that plum can contribute to the dietary intake of antioxidants, depending on cultivars and fruit parts. It is among the few studies investigating the distribution of total phenolic, total flavonoids and total antioxidant capacity in the skin, pulp and fruit of plum cultivars. It was observed that the highest values of total phenolic and flavonoid content were obtained from skin extracts. The study highlighted that phenolics and flavonoids in plums may play an important role as radical-scavenging agents that could be used for a healthy human life. This fact may open new perspectives for plumbesides its traditional uses -to be used in assuring a wholesome diet and a healthy life.

Introduction. The objective of this study was to investigate some nutritional and functional components of the walnut fruit kernel and pellicle across twelve genotypes of Juglans regia L., six with a red pellicle and six with a light yellow pellicle. Materials and methods. Antioxidant activity, and contents of total phenolics, flavonoids, minerals and trace elements were determined as well as anthocyanins in red pellicles. Results and discussion. Total phenolic content ranged from 1,131 to 2,892 mg GAE 100 g −1 in kernels and from 11,525 to 33,833 mg GAE 100 g −1 in pellicles. The ratio between the average content in pellicles and that in kernels was found to be 12.7 for total phenolics and 12.9 for the antioxidant activity. Significantly higher average levels of total phenolic content and flavonoid content were found in yellow pellicles than in red pellicles, while no significant differences between the two groups of genotypes were found in kernels. High concentrations of anthocyanins were found in the red pellicles (1,636−2,956 mg CGE 100 g −1). The contents of calcium, magnesium, iron and manganese were significantly higher in genotypes with a red pellicle compared with genotypes with a yellow pellicle both in kernels and pellicles, while the opposite is true for potassium and sodium. Conclusion. The data confirm that walnuts are a good dietary source of total phenolics with high antioxidant potential, minerals (Ca, Mg and K) and essential elements (Fe, Mn, Cu and Zn), most of which are concentrated in the walnut pellicle. Despite the large amounts of anthocyanins found in the red pellicles, yellow pellicles had a stronger antioxidant activity than red pellicles. Keywords: Romania / walnut / Juglans regia / phenolics / antioxidant activity / mineral composition / nutritional value Résumé-Activité antioxydante, teneurs en composés phénolique et minéraux de la noix (Juglans regia L.) en fonction de la couleur de la pellicule de l'amande. Introduction. L'objectif de cette étude était d'étudier certains composants nutritionnels et fonctionnels de l'amande du fruit du noyer et de sa pellicule à travers douze génotypes de Juglans regia L., dont six à pellicule rouge et six à pellicule jaune clair. Matériels et méthodes. L'activité antioxydante, les teneurs en composés phénoliques totaux, en flavonoïdes, en minéraux et oligo-éléments ont été déterminées, ainsi que les teneurs en anthocyanines des pellicules rouges. Résultats et discussion. La teneur totale en composés phénoliques a varié entre 1 131 et 2 892 mg GAE 100 g −1 dans les noix et entre 11 525 et 33 833 mg GAE 100 g −1 dans les pellicules. Le rapport entre la teneur moyenne des pellicules et celle des noix a été de 12,7 pour les composés phénoliques totaux et de 12,9 pour l'activité anti-oxydante. Des niveaux moyens significativement plus élevés de teneur en composés phénoliques totaux et en flavonoïdes ont été trouvés dans les pellicules jaunes que dans les pellicules rouges, tandis que pour les noix aucune différence significative n'a été observée entre l...