Antioxidant and antimicrobial activity of two Asplenium species

Abstract

Extracts of the aerial (fronds) and underground parts (rhizome and roots) of Asplenium adiantum-nigrum L. and Asplenium ruta-muraria L. were analyzed for their phenolic composition and antioxidant properties (scavenging capacities against DPPH center dot and ABTS(center dot+)), and were comparatively assayed for antimicrobial and antibiofilm activity. Total of the 17 phenolic compounds, belonging to the classes of phenolic acids (hydroxybenzoic and hydroxycinnamic acids), flavonoids (flavan-3-ols, flavonols), and xanthones were identified and quantified using UHPLC/DAD/(-)HESI-MS/MS analysis. The present study shows that two analyzed ferns are significantly diverse in terms of their phenolic profile. Flavonoids considerably contribute to the total phenolic content of A. ruta-muraria, ranging from 47% in roots to around 75% in rhizome and fronds, while A. adiantum-nigrum preferably accumulates xanthones. Antioxidant activity of fern methanol extracts was ascribed to their phenolics content. Extracts of rhizomes of both Asplenium ferns exhibited the highest antimicrobial activity, while frond extracts were more efficient in inhibition of Candida albicans biofilm formation. The present study provides experimental evidence that methanol extracts from two analyzed Asplenium fern species exhibit strong antibacterial effect against Gram-negative bacteria which candidate them as a potentially useful natural antimicrobial agents.