Ellagitannins from Raspberry (Rubus idaeus L.) Fruit as Natural Inhibitors of Geotrichum candidum.

The paper presents the chemical characteristics of ellagitannins isolated from raspberry (Rubus idaeus L.) fruit and their in vitro and in situ antifungal activity against Geotrichum candidum LOCK 0511. The study investigated a complex preparation containing various raspberry ellagitannins at a concentration of 86% w/w, as well as pure lambertianin C and sanguiin H-6. The ellagitannin preparation was obtained by extracting raspberry press cake and purifying the extract using Amberlite XAD resin, while individual compounds were isolated by means of preparative HPLC. The complex preparation was analyzed for the content of ellagitannins, anthocyanins, and flavan-3-ols using HPLC and LC-MS. The antifungal activity of the complex ellagitannin preparation and the isolated ellagitannins was determined for the strain Geotrichum candidum. The MIC and MFC values (10.0 mg/mL and 30.0 mg/mL, respectively) were found to be the same for lambertianin C, sanguiin H-6, and the complex ellagitannin preparation. The fungistatic activity of the studied ellagitannin preparation at a concentration of 10 mg/mL, as determined by the poisoned medium method, was 65.2% following 6 day incubation of Geotrichum candidum, with the linear growth rate of only 16.2 mm/day. The corresponding parameters for the control sample were 0% and 56 mm/day, respectively. The study demonstrated both in vitro and in situ antifungal activity of raspberry ellagitannins against Geotrichum candidum.

Designing laser-modified surface structures on titanium alloy custom medical implants using a hybrid manufacturing technology.

The hybrid technology combines an efficient material-removal process and implant surface treatment by the laser reducing time of manufacture process compared to currently used machining technologies. It also permits precise structuring of the implant material surface. Six structures of the Ti6Al4V ELI surface were designed and studied how the structure topography prepared with the hybrid technology affected the Escherichia coli adhesion to the surface and viability, as well as the growth, adhesion, and viability of human osteogenic Saos-2 cells cultured on the investigated surfaces. Results have confirmed that the microtopography of medical titanium alloy plays a beneficial role in bacterial adhesion and viability (number of bacteria found on reference surface: [5.9 ± 0.44] × 106 CFU/ml, sample no. 3: [8.8 ± 0.93] × 104 CFU/ml, and sample no. 5: [1.2 ± 0.23] × 107 CFU/ml; CFU - Colony Forming Unit). All tested structured surfaces enabled good cell attachment and proliferation of Saos-2 cells (viability of Saos-2 cells [% of control] for reference surface: 81.93%; sample no. 3: 75% and sample no. 5: 100%). Transcriptome analysis of genes commonly expressed in the process of osseointegration demonstrated that the use of hybrid technology allows designing structures that enhance osseointegration but it should be coupled with other methods of preventing bacterial growth, or with a different strategy to limit microbial colonization with the satisfactory osseointegration potential.

Antifungal Activity of Lactobacillus pentosus LOCK 0979 in the Presence of Polyols and Galactosyl-Polyols.

The antifungal activity of Lactobacillus pentosus LOCK 0979 depends both on the culture medium and on the fungal species. In the control medium, the strain exhibited limited antagonistic activity against indicator food-borne molds and yeasts. However, the supplementation of the bacterial culture medium with polyols (erythritol, lactitol, maltitol, mannitol, sorbitol, xylitol) or their galactosyl derivatives (gal-erythritol, gal-sorbitol, gal-xylitol) enhanced the antifungal properties of Lactobacillus pentosus LOCK 0979. Its metabolites were identified and quantified by enzymatic methods, HPLC, UHPLC-MS coupled with QuEChERS, and GC-MS. The presence of polyols and gal-polyols significantly affected the acid metabolite profile of the bacterial culture supernatant. In addition, lactitol and mannitol were used by bacteria as alternative carbon sources. A number of compounds with potential antifungal properties were identified, such as phenyllactic acid, hydroxyphenyllactic acid, and benzoic acid. Lactobacillus bacteria cultivated with mannitol synthesized hydroxy-fatty acids, including 2-hydroxy-4-methylpentanoic acid, a well-described antifungal agent. Scanning electron microscopy (SEM) and light microscopy confirmed a strong antifungal effect of L. pentosus LOCK 0979.

Ellagitannins from Rubus idaeus L. Exert Geno- and Cytotoxic Effects against Human Colon Adenocarcinoma Cell Line Caco-2.

Ellagitannins possess several biological activities, including anticancer properties. The goal of the present study was to investigate the cyto- and genotoxic activities of a red raspberry ellagitannin preparation (REP) in the concentration range of 2.5-160 µg/mL, as well as that of the main individual raspberry ellagitannins, sanguiin H-6 (SH-6, 12.8-256 µM) and lambertianin C (LC, 9.3-378 µM), against human colon adenocarcinoma cell line Caco-2. The ellagitannin concentrations used in the study correspond to those found in foodstuffs containing raspberry fruit. REP, SH-6, and LC exhibited strong concentration-dependent genotoxic properties, inducing DNA damage ranging from 7.3 ± 1.3 to 56.8 ± 4.3%, causing double-strand breaks and oxidation of DNA bases. At IC50 (124 µg/mL) the REP affected the nuclear morphology and induced the apoptosis of Caco-2 cells. Because the REP has been found to possess chemopreventive activity, it can be used as a natural food additive to enhance the health benefits of foodstuffs.

Antifungal Activity of Lactobacillus sp. Bacteria in the Presence of Xylitol and Galactosyl-Xylitol.

Lactic acid fermentation is a natural method of antimicrobial food protection. Antagonistic activity of Lactobacillus sp. bacteria, taking part in this process, is directed mainly against the same or other microorganisms. In this work we determine the impact of the presence of xylitol and galactosyl-xylitol on the antagonistic activity of 60 Lactobacillus sp. strains against indicator molds (Alternaria alternata, Alternaria brassicicola, Aspergillus niger, Fusarium latenicum, Geotrichum candidum, and Mucor hiemalis) and yeasts (Candida vini). We used double-layer method to select antifungal strains of Lactobacillus bacteria and poisoned medium method to confirm their fungistatic properties. Additionally, we examined the inhibition of Alternaria brassicicola by Lactobacillus paracasei LOCK 0921 cultivated with xylitol or galactosyl-xylitol directly on wild cherries. The presence of xylitol and its galactosyl derivative led to increase of spectrum of antifungal activity in most of the studied plant-associated lactobacilli strains. However, no single strain exhibited activity against all the indicator microorganisms. The antifungal activity of Lactobacillus bacteria against molds varied considerably and depended on both the indicator strain and the composition of the medium. The presence of xylitol and galactosyl-xylitol in the growth medium is correlated with the antifungal activity of the studied Lactobacillus sp. bacteria against selected indicator molds.

The structure, occurrence and biological activity of ellagitannins: a general review.

The present paper deals with the structure, occurrence and biological activity of ellagitannins. Ellagitannins belong to the class of hydrolysable tannins, they are esters of hexahydroxydiphenoic acid and monosaccharide (most commonly glucose). Ellagitannins are slowly hydrolysed in the digestive tract, releasing the ellagic acid molecule. Their chemical structure determines physical and chemical properties and biological activity. Ellagitannins occur naturally in some fruits (pomegranate, strawberry, blackberry, raspberry), nuts (walnuts, almonds), and seeds. They form a diverse group of bioactive polyphenols with anti-inflammatory, anticancer, antioxidant and antimicrobial (antibacterial, antifungal and antiviral) activity. Furthermore, they improve the health of blood vessels. The paper discusses the metabolism and bioavailability of ellagitannins and ellagic acid. Ellagitannins are metabolized in the gastrointestinal tract by intestinal microbiota. They are stable in the stomach and undergo neither hydrolysis to free ellagic acid nor degradation. In turn, ellagic acid can be absorbed in the stomach. This paper shows the role of cancer cell lines in the studies of ellagitannins and ellagic acid metabolism. The biological activity of these compounds is broad and thus the focus is on their antimicrobial, anti-inflammatory and antitumor properties. Ellagitannins exhibit antimicrobial activity against fungi, viruses, and importantly, bacteria, including antibiotic-resistant strains such as methicillin-resistant Staphylococcus aureus.