The Flavonoid Rich Black Currant (Ribes nigrum) Ethanolic Gemmotherapy Extract Elicits Neuroprotective Effect by Preventing Microglial Body Swelling in Hippocampus and Reduces Serum TNF-α Level: Pilot Study

Comparative evaluation of physiological and molecular responses of blackcurrant varieties to powdery mildew infection

The black currant (Ribes nigrum L.), a member of the Saxifragaceae family's Ribes genus, has gained consumer and grower acceptance due to its high nutritional value and economic potential. However, powdery mildew, the primary leaf disease affecting black currants, significantly impacts growers and the industry. Developing varieties highly resistant to powdery mildew is currently considered the most scientifically sound solution. However, the black currant's physiological and disease resistance mechanisms post-infection by powdery mildew remain understudied, thereby impeding further breeding efforts. Therefore, this study aimed to elucidate the pathogenesis of powdery mildew in various susceptible varieties, post-infection physiological changes, and molecular mechanisms related to powdery mildew. This was achieved through phenotypic observation, physiological data analysis, transcriptomic analysis, and qRT-PCR-mediated gene expression analysis.

Specific Antimicrobial Activities Revealed by Comparative Evaluation of Selected Gemmotherapy Extracts

Nowadays, unprecedented health challenges are urging novel solutions to address antimicrobial resistance as multidrug-resistant strains of bacteria, yeasts and moulds are emerging. Such microorganisms can cause food and feed spoilage, food poisoning and even more severe diseases, resulting in human death. In order to overcome this phenomenon, it is essential to identify novel antimicrobials that are naturally occurring, biologically effective and increasingly safe for human use. The development of gemmotherapy extracts (GTEs) using plant parts such as buds and young shoots has emerged as a novel approach to treat/prevent human conditions due to their associated antidiabetic, anti-inflammatory and/or antimicrobial properties that all require careful evaluations. Seven GTEs obtained from plant species like the olive (Olea europaea L.), almond (Prunus amygdalus L.), black mulberry (Morus nigra L.), walnut (Juglans regia L.), blackberry (Rubus fruticosus L.), blackcurrant (Ribes nigrum L.) and bilberry (Vaccinium myrtillus L.) were tested for their antimicrobial efficiency via agar diffusion and microbroth dilution methods. The antimicrobial activity was assessed for eight bacterial (Bacillus cereus, Staphylococcus aureus, Salmonella enterica subsp. enterica, Proteus vulgaris, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa and Listeria monocytogenes), five moulds (Aspergillus flavus, Aspergillus niger, Aspergillus ochraceus, Penicillium citrinum, Penicillium expansum) and one yeast strain (Saccharomyces cerevisiae). The agar diffusion method revealed the blackberry GTE as the most effective since it inhibited the growth of three bacterial, four moulds and one yeast species, having considered the total number of affected microorganism species. Next to the blackberry, the olive GTE appeared to be the second most efficient, suppressing five bacterial strains but no moulds or yeasts. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were then determined for each GTE and the microorganisms tested. Noticeably, the olive GTE appeared to feature the strongest bacteriostatic and bactericidal outcome, displaying specificity for S. aureus, E. faecalis and L. monocytogenes. The other GTEs, such as blueberry, walnut, black mulberry and almond (the list indicates relative strength), were more effective at suppressing microbial growth than inducing microbial death. However, some species specificities were also evident, while the blackcurrant GTE had no significant antimicrobial activity. Having seen the antimicrobial properties of the analysed GTEs, especially the olive and black mulberry GTEs, these could be envisioned as potential antimicrobials that might enhance antibiotic therapies efficiency, while the blackberry GTE would act as an antifungal agent. Some of the GTE mixtures analysed have shown interesting antimicrobial synergies, and all the antimicrobial effects observed argue for extending these studies to include pathological microorganisms.

Phenolic Compounds in Fractionated Blackcurrant Leaf Extracts in Relation to the Biological Activity of the Extracts

The aim of this study was to determine the relationship between antioxidant and anticancer properties of extracts from blackcurrant (Ribes nigrum L.) leaves and their fractions and chemical contents. Dried ethanolic extract was divided into three fractions using solid phase extraction: aqueous (F1), 40% MeOH (F2), and 70% MeOH (F3). Both the extract and the fractions were analyzed in terms of antiradical activity (DPPH• and ABTS+•), total phenolic compounds, and total flavonoids. The antitumor potential of the fractions was evaluated in vitro on human colorectal (HCT 116) and prostate (PC-3) cancer cells. Phenolics were identified using HPLC-QTOF-MS, and twelve compounds were quantified by HPLC-DAD. Finally, principal component analysis was carried out to assess the relationship between the tested factors. The results confirmed that blackcurrant leaves are a rich source of phenolics with high antioxidant activity and anticancer properties. It was demonstrated that the F2 fraction had the highest content of phenolics and the highest antiradical activity. Additionally, only this fraction showed cytotoxic activity against HCT 116 cells. It was confirmed that both the blackcurrant leaf extract and its fractions are a promising source of condensed active compounds and can be used as natural functional food additives.