In this study, we analyzed extracts of Ribes (black currant, red currant and gooseberry) fruits obtained with methanol, methanol 50% and water. For each extract total polyphenol content, total flavonoid content and total anthocyanin content was assessed. The antioxidant activity of extracts was evaluated by 1,1-Diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging capacity and by the photo-chemiluminescence (PCL) method. Identification and quantification of individual phenolic compounds was performed by means of high performance liquid chromatograph coupled with diode array detector (HPLC-DAD) analyses. From each fruit, best extraction of polyphenols was obtained with methanol 50%. In case of red currants and gooseberry there was no significant difference in flavonoids and anthocyanins extraction rate by the different extraction solvents. For black currants the methanol and methanol 50% extract presented the highest antioxidant activity. For red currants extracts with methanol 50% showed stronger antioxidant activity (IC = 5.71 mg/ml for DPPH, IC = 1.17 mg/ml for ABTS) than those with methanol or water. In case of gooseberry by the DPPH test the water extract proved to be the most active (IC = 5.9 mg/ml). In the PCL test black currants methanol 50% extract was over 6 times more powerful as the ones from red currants. In case of gooseberries, water extract presented the highest antioxidant activity (41.84 μmol AAE/g). In black currant cyanidin-3-glucoside was the major compound. Quercetin 3-O-glucoside was identified in each sample. From cinnamic acid derivatives neochlorogenic acid was present in black currants in the highest amount (356.33 μg/g).

To complete the wide range of studies on chemical composition and pharmacological potential of the fruit of Ribes nigrum and Ribes rubrum, this work aimed to perform a comparative morpho-anatomical characterization of the fruits of both species and complete previously records of black currant as frequently studied species. Microslides of fruits were made with rotation microtome, and then cross sections were stained with toluidine blue. Documentation and evaluation were carried out in microphotos. In R. rubrum, the epidermis cells are ovoid to round, while those of R. nigrum are rectangular to almost round. Under the epidermis, in both fruits, there are two layers of oval hypodermal cells. Underneath the hypodermal layers, parenchyma cells of different size with thin walls and scattered collateral closed bundles were detected. The seeds are embedded in a gelatinous sheath having large thin-walled cells. Endocarp separates the arillar tissue from parenchyma cells, in addition, a gap can be found among these layers, endocarp, arillar tissue, and seeds. The seed coat consists of sclerenchyma cells in both species. In conclusion, histological differences and similarities were described in the fruits of the selected Ribes species, highlighted the first morpho-anatomical description of the berry of Ribes rubrum.