UHPLC-MS/MS Comprehensive Phytochemical Investigation of Niphidium crassifolium Rhizome: Bioactivity Assessment With...

Niphidium crassifolium (Linnaeus) Lellinger is a fern from the Polypodiaceae family, native to Central and South America, with traditional uses in herbal medicine. Despite its recognized ethnomedical value, its phytochemical composition has not been extensively studied. This pioneering work aimed to determine the metabolite profile from rhizomes of N. crassifolium, to quantify the contents of phenols and flavonoids, and to evaluate their antioxidant and antibacterial activities.

Metabolite characterization was performed using LC-MS/MS, while radical scavenging activity (DPPH^• and ABTS^•+ assays) was used to estimate in vitro antioxidant potential. Trolox was used as reference standard in both assays. Phenolic and flavonoid contents as well as antioxidant activity were evaluated in four anatomical parts: complete rhizome, proximal rhizome, distal rhizome, and adventitious root.

This study identified the presence of saponins, phytoecdysteroids, flavones, phenolic acids, and phenolic glycosides. Proximal rhizome exhibited the highest phenolic content (264.6 ± 0.15 mg GAE/g), whereas adventitious root showed the highest flavonoid content (54.0 ± 0.47 mg RUE/g). Median effective concentration of proximal rhizome was 50.4 ± 0.03 μg/mL (DPPH^•) and 310.7 ± 1.9 μg/mL (ABTS^•+), compared to Trolox values of 37.4 ± 0.01 μg/mL and 155.0 ± 0.3 μg/mL, respectively (p < 0.05). Despite slightly higher EC₅₀ values than Trolox, proximal rhizome's antioxidant capacity was statistically significant (p < 0.05). Plant exhibited selective antibacterial activity against Gram-positive bacteria, particularly Staphylococcus aureus ATCC 6538 (inhibition halo, 16.5 ± 0.09 mm; minimum inhibitory concentration, 13 370 μg/mL) and Bacillus spizizenii ATCC 6633 (inhibition halo, 12.6 ± 0.40 mm; minimum inhibitory concentration, 3 230 μg/mL).

These findings underscore the value of N. crassifolium as a promising source of antioxidant and antibacterial compounds. Data support its ethnomedical applications and underscore the potential for development into natural therapeutic agents targeting oxidative stress and Gram-positive infections that pave the way for future pharmaceutical and nutraceutical development.