Antifungal activity and phenolic profiles of Paliurus spina-christi seeds from different regions of Türkiye

Background and Aims This study aims to reveal the regional differences in total phenolic content and antifungal activities of Paliurus spina-christi Mill. seed extracts collected from three distinct regions of Türkiye: Anamur (Mersin), Bayramiç (Çanakkale), and Fethiye (Muğla). Methods Seed samples were subjected to ultrasonic-assisted ethanol extraction; prior to antifungal assays, the solvent was completely removed using a rotary evaporator. Total phenolic content was determined by the Folin–Ciocalteu method, and antifungal activity against Penicillium italicum and Aspergillus niger was evaluated via the disk diffusion method. Statistical analyses were performed using one-way ANOVA and Tukey’s post-hoc test (p < 0.05). Results Significant regional variations were observed in total phenolic content, with Fethiye (Muğla) samples exhibiting the highest concentration. Antifungal assays demonstrated that only the extract from Fethiye showed a biologically meaningful inhibitory effect (net inhibition zone ≥ 5 mm) against P. italicum, while activity against A. niger was negligible for all extracts. Furthermore, no direct correlation was found between total phenolic content and antifungal efficacy. Conclusion These findings suggest that the antifungal activity in P. spina-christi seeds may depend on specific bioactive compounds rather than total phenolic concentration alone, highlighting the significant influence of geographic origin on plant bioactivity.