Sumlu, Esra; Aydin, Merve; Korucu, Emine Nedime; Ozturk, Ali; Emsen, Bugrahan

The increasing prevalence of Candida infections and growing concerns about antifungal resistance have encouraged research into new therapeutic agents from natural sources. This study investigated the antifungal activity of Dermatocarpon miniatum (L.) W. Mann and Parmelia saxatilis (L.) Ach. lichen extracts against Candida species, focusing on their antibiofilm effects and underlying molecular mechanisms. Methanol and aqueous extracts of both lichens were prepared and evaluated against four reference and 19 clinical Candida strains using microdilution methods. This study employed a multi-modal approach to explore the antibiofilm effect of lichen extracts on Candida albicans, including CCK-8 assay for antibiofilm capacity, qRT-PCR for biofilm-related (cAMP-PKA and Cek1 MAPK pathways) gene expressions, field emission scanning electron microscopy for morphological assessment, and Galleria mellonella infection model for in vivo evaluation. Antifungal susceptibility tests revealed only methanol extracts showed antifungal activity, with minimum inhibitory concentrations ranging from 160 to 2500 μg/mL for P. saxatilis methanol extract (ParM) and 320–2500 μg/mL for D. miniatum methanol extract (DerM). ParM (1250 μg/mL) significantly reduced biofilm formation and down-regulated key genes involved in both pathways. Methanol extracts of lichens disrupted hyphal networks and cell integrity. In the Galleria mellonella model, DerM provided protection similar to fluconazole, while ParM provided 60 % survival. These findings indicate that lichen extracts, particularly ParM, inhibit Candida albicans biofilm formation by downregulating genes in the cAMP-PKA and Cek1 MAPK pathways. Despite the promising antibiofilm and in vivo activities of these extracts, their limited antifungal activity against Candida suggests that further research is needed for their therapeutic potential.

Arslan, Betul; Xiong, Youling L.; Soyer, Ayla

The objective of the present study was to evaluate the stability of low-molecular-weight peptides after their incorporation into fermented sausages. Peptide fractions were produced from the bovine liver peptides (BLP) by enzymatic hydrolysis. Optimal conditions were identified as hydrolysis at 45 °C for 24 h, resulting in the generation of <3 kDa and <10 kDa peptide fractions exhibiting the highest antioxidant activity. The antioxidant potential of fermented sausages made from beef meat containing BLPs at 0.5% and 1% concentrations was assessed during manufacturing and storage. The initial antioxidant activity values of the sausages containing BLPs were higher than that of the control. Furthermore, the stability of the peptides in the sausages was demonstrated by their preserved antioxidant activity for 102 days. Peptides extracted from 1% of <10 kDa-peptide containing sausages possessed two-fold higher radical scavenging activity than control. The highest peptide concentration in the sausages containing 1% of <10 kDa-peptides (79.32±1.34–101.56±1.22 μg peptide/mg) was maintained from day 0 to day 102. The SDS-PAGE profile of myofibrillar proteins and peptide extracts revealed the degradation of proteins were delayed in <10 kDa of peptide added sausages, suggesting that the protein oxidation was slowed down. These results contribute to the advancement of peptide commercialization as functional ingredients in fermented food products. Furthermore, our research sheds light on the enduring impact of fermentation on the stability of the added peptides and the synergistic interactions between naturally produced peptides during fermentation and those introduced externally.

Bayrakçeken Güven, Zühal; Alshehri, Osama; Yüce, Neslihan; Bakan, Ebubekir; Demirci, Betül; Yilmaz, Mustafa Abdullah; Ertas, Abdulselam; Basaran, A.Ahmet

Prunus mahaleb L. seeds are widely used in the baking industry as spice for flavouring. While achieving the mahaleb powder for commercial use in local companies, the seeds are sometimes mixed unintentionally with their kernels (stony shell) during sieving procedure. As the chemical and biological properties of the kernel of seeds are not well known, the kernel, seeds and the market sample obtained from a local supplier are decided to investigate individually. The antioxidant capacity and the trace element analyses of the seeds and kernels were performed by TEAC and CUPRAC assays and ICP-MS. The market sample was analysed for nutrient and oil composition. Fatty acid composition of the oil was determined with GC-FID and GC-MS methods. The chemical composition of the methanol extract of the seeds and kernels was studied by LC-MS/MS. Trace elements Mn, Co, Ni, Cu, Zn and Se were determined in the methanol extracts, ethyl acetate and water fractions. Mushroom tyrosinase enzyme inhibitions of 33 different extracts and fractions of various waste parts of the plant (kernel, fruit, twigs, flos, leaves) were investigated. The nutritional values showed that the market sample had high nutritious properties. The fatty acid content of the oil was found to be valuable in remedying dysfunctions of the body. Kernel ethylacetate fraction showed the highest tyrosinase enzyme inhibition. The role of copper element on enzyme activity was determined. The kernels are accepted as a waste material may also be evaluated as a good promising choice for food, cosmetic and drug industry.

Bayrakçeken Güven, Zühal; Dogan, Zeynep; Saracoglu, Iclal; Picot, Laurent; Nagatsu, Akito; Basaran, A. Ahmet

Prunus mahaleb L. seeds are used as spice and folk remedies in many countries. The aim of this study was bioactivity guided isolation and characterization phytoconstituents of P. mahaleb which have been studied very limited so far. The antioxidant capacities of seed and kernel (endocarp) extracts were studied by DPPH, nitric oxide (NO), superoxide (SO), TEAC, CUPRAC methods. The antiproliferative activity were investigated for the first time against B16F10, A2058, HeLa and L929 cell lines using MTT assay. Gallic acid and ursolic acid which have strong antioxidant and cell growth inhibitory effect, were isolated from the most active fractions. From the inactive fractions, quercetin-3-O-(2-O,6-O-α-dirhamnopyranosyl β-glucopyranoside), kaempferol-3-O-(2-O,6-O-α-dirhamnopyranosyl β-glucopyranoside) and β-sitosterol 3-O-β-glucopyranoside were isolated. Our study is the first record for the isolation of ursolic acid from all parts of P. mahaleb, gallic acid from P. mahaleb kernels, two flavonol triglycosides from the Prunus species and their analysis by advanced NMR spectroscopic methods. Ursolic acid (IC50: 170.2 μM) and gallic acid (IC50: 10.5 μM) showed strong tyrosinase inhibition, gallic acid being 5.4 times more effective than standard compound. Kernel extracts have strong antioxidant activity, showed high growth inhibitory activity with dose-dependent manner on melanoma cells but no growth inhibitory on healthy L929 and HeLa cancer cells. The high antioxidant capacity of kernel, its selective growth inhibition of B16F10 and A2058 melanoma cells and its strong tyrosinase inhibitory compounds suggest that it could be a new, non-toxic and inexpensive resource for melanoma treatment and cosmetic industry.