We investigated the total phenolic and flavonoid contents and the anthocyanin profiles in aqueous, ethanol and acetone extracts of Prunus spinosa (Rosaceae) fruit, and their antioxidant, antibacterial, antifungal, antidiabetic and antitumor properties. The contribution of polyphenol contents to the bioactivity of the extracts was calculated and observed through Pearson's coefficient of correlation. The acetone extract was the richest in phenols and anthocyanins and the ethanol extract in flavonoids. Cyanidin was the most abundant anthocyanin compound in all examined extracts. The ethanol extract showed the most promising antioxidant activity in DPPH, ABTS and FRAP assays. Tested bacteria were more affected by the ethanol than by the aqueous extract. Both the ethanol and aqueous extracts exhibited potential antidiabetic effects, observed as inhibition of α-amylase and α-glucosidase, enzymes linked with diabetes mellitus type II. The ethanol extract was a potent α-glucosidase-inhibitor with a significantly lower IC50 value than the positive control, glucobay, used to treat diabetes mellitus type II. Neither the ethanol nor the aqueous extracts had any effects on tested human malignant cell lines. Our results indicate that the ethanol extract showed the most pronounced in vitro antioxidant and antimicrobial effects, and a potential antidiabetic activity, which can be ascribed to its high flavonoid content. Our results indicate that research of compounds, particularly of flavonoids present in the ethanol extract and their anti-diabetic properties should be examined further.

The presented study was aimed at exploring the bioactive properties (antioxidant, antimicrobial and food preserving) and chemical composition of R. discolor fruits collected from 2 geographically distinct wild-growing populations and extracted by using different solvents (methanol, ethanol, acetone and water). The total phenol (TPC), flavonoid (TFC) and anthocyanin (TAC) content varied from 52.7 to 186.8 mg GAE/g, 3.5 to 7.0 mg QE/g and 11.1 to 28.2 mg/g dry weight (dw), respectively. HPLC-DAD analysis identified cyanidin-3-glucoside (Cy-3-Glu) as the dominant anthocyanin that ranged in concentration from 18.4 to 32.2 mg/g dw. The acetone extract revealed the highest antioxidant activity through the ferric reducing antioxidant power (FRAP), total reducing power (TRC) and ß-carotene bleaching in vitro methods. The examined extracts showed antimicrobial activity, being more effective against Gram-positive (G+) than Gram-negative (G-) bacteria. Furthermore, Candida glabrata was the most susceptible among the pathogenic yeasts. The ethanol fruit extract was the most active against Listeria monocytogenes and thus chosen for incorporation in yoghurt and further analyses regarding its food preserving properties, which confirmed its efficacy towards this food-borne pathogen. Additionally, panelists gave high marks to the novel product regarding color, taste, texture flavor and overall acceptance. The obtained results indicated that R. discolor fruit extracts exhibits notable bioactivity and might therefore be considered as a good platform for the development of new preparations to be used in the food industry.

Prunus spinosa leaf extracts in solvents of different polarity (water, ethanol and acetone), their phenol, flavonoid and anthocyanin contents and biological properties were the object of this study. The richest in phenols as well as in flavonoids was acetone extract with 181.19 mg GAE and 80.10 mg QE per gram of dry extract, respectively. Moreover, the quantity of anthocyanins obtained by HPLC analysis was also the highest in acetone sample. Examined samples possessed antioxidant properties evaluated through four in vitro assays (DPPH, ABTS, FRAP and TRC). The acetone extract was proved to be the best antioxidant among tested samples, which could be ascribed to polyphenols, especially anthocyanins. The aqueous and the ethanol extract exhibited antibacterial effects, being particularly active against B. cereus and E. cloacae. T. viride, P. funiculosum, P. ochrochloron, P. verrucosum var. cyclopium were the most susceptible among fungal microorganisms examined. Both, the aqueous and the ethanol extract expressed inhibitory activity towards enzymes linked to diabetes mellitus type II. Additionally, the ethanol extract showed significantly higher potential in inhibiting α-glucosidase than the drug used as the positive control. Furthermore, the aqueous sample revealed antitumor effects on following malignant cell lines: HeLa, K562 and MDA-MB-453. The results presented herein suggest that P. spinosa leaves should be considered as a natural source of bioactive compounds with potential application in phytopharmacy and food industry.

In this study, the antioxidant properties and total phenolic and flavonoid contents of Rubus caesius L. var. aqu?ticus Weihe & Nees leaf extracts were examined. The radical scavenging capacity of four leaf extracts (methanol, ethanol, acetone and aqueous) was estimated against 2,2-diphenyl-1-picrylhydrazil (DPPH) and 2,2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) assays. Total antioxidant capacity was tested by ferric reducing ability of plasma (FRAP) and total reducing capacity (TRC) procedures. Total contents of phenols and flavonoids were also determined. Total phenol content in the extracts was determined using Folin-Ciocalteu reagent and amounts ranged between 263.74 for ethanol to 366.27 mg gallic acid (GA)/g for acetone extracts. The amounts of flavonoids varied from 10.73 mg quercetin equivalent (QE)/g for aqueous to 75.83 mg QE/g for acetone extract. The highest antioxidant activity against DPPH and ABTS?+ radicals was that of the acetone extract. Values for FRAP varied between 3.00 ?mol Fe+2/mg for the ethanol extract and 5.31 ?mol Fe+2/mg for the methanol extract. The results obtained for total reducing capacity indicate that the acetone extract has the highest antioxidant potential. [Projekat Ministarstva nauke Republike Srbije, br. 173029]