Screening of antimicrobial, antibiofilm and cytotoxic activities of some medicinal plants from Balıkesir province, Türkiye: pointing to the potential effects of Allium paniculatum flower

INTRODUCTION: Plant extracts are important natural resources that may have antimicrobial and antibiofilm effects against pathogens. This study was conducted to investigate the in vitro antimicrobial activities of the methanol extracts of some medicinal plants (Achillea nobilis L. subsp. neilreichii (A.Kern.) Velen., Aetheorhiza bulbosa (L.) Cass, Allium paniculatum L, Asphodelus aestivus Brot., Ballota nigra L., Cistus laurifolius L., Cistus salviifolius L., Dioscorea communis (L.) Caddick & Wilkin, Galium verum L., Hypericum triquetrifolium Turra, Paliurus spina-christi Mill., Primula vulgaris Huds. subsp. rubra (Sm.) Arcang., Ranunculus arvensis L. and Teucrium polium L.) from Balıkesir province in Türkiye.
METHODS: Preliminary antimicrobial acitivity screening was conducted for all extracts. Antibiofilm activity studies were performed against Candida albicans mature biofilms. Moreover, cytotoxicities of A. paniculatum flower extract on A549 and Vero cell lines were determined using a colorimetric tetrazolium-based assay.
RESULTS: A. paniculatum flower, P. vulgaris root, C. laurifolius, C. salviifolius and A. nobilis were displayed good antimicrobial activity (MICs: 9.75, 156, 312, 312 and 312 µg/ml, respectively) against Candida albicans ATCC 10231. The biofilm studies were performed to these plant extracts. The methanol extract of A. paniculatum flower decreased the number of C. albicans (cfu/ml) in mature biofilm statistically at 32xMIC and higher concentrations (P < 0.01). A. paniculatum flower extract had a cytotoxic effect (killing more than 50% of cells) at high concentrations, and its effect on Vero cell was similar to that on A549 cell.
DISCUSSION AND CONCLUSION: This study demonstrates the importance of the methanol extract of A. paniculatum flower as natural alternative against C. albicans infections including biofilms.