<i>Nephrolepis cordifolia</i> (L.) C.Presl Frond Micromorphology, Hydrosol Phytochemical Profiling, and Antibacterial Activity Against Foodborne Bacteria

Fern species from biodiversity-rich northeastern India are relatively underexplored. Morphological, phytochemical, and antimicrobial profiling of Nephrolepris cordifolia (L.) C.Presl has been undertaken in the present study. The morphological structure of frond epidermal cells and spores has been revealed through light microscopy (LM) and scanning electron microscopy (SEM) observation, including the size measurement of epidermal and stomatal cells. The spores are ellipsoidal, having a polar-to-equatorial ratio of 0.89. SEM confirmed the existence of a typical verrucate type of exine ornamentation of the spores. Phytochemical analysis based on GC-MS analysis of N. cordifolia hydrosol (NH01) indicated the presence of six phytochemical compounds, with methyl-9-eicosenoate as the most volatile with an RT value of 36.76 and 2,3-dihydrobenzofuran considered a volatile bioactive component having RT value of 21.35. Functional group detection of the hydrosol has revealed an aldehydic C─H functional group that was corroborated through FTIR analysis. Microbial growth inhibitory capability analysis also displayed an inhibitory potential against foodborne spoilage bacteria, including both Gram-positive and Gram-negative bacteria, exhibiting more effectiveness against Gram-positive bacteria with lower MICs value of 50 µg/mL, thus indicating hydrosol feasible for application in food protection as antimicrobial potency agent.