Antibacterial efficacy of Drynaria quercifolia (L.) J. Smith (Polypodiaceae) against clinically isolated urinary tract pathogens

Aglaomorpha quercifolia (L.) Hovenkamp & S. Linds a Wild Fern Used in Timorese Cuisine

Aglaomorpha quercifolia (L.) Hovenkamp & S. Linds is an extensively used species in traditional medicinal systems in several areas of the world due to some important medicinal properties such as antioxidant, antibacterial, analgesic, and anti-inflammatory activities. In East Timor, different parts of this fern are used either as remedies or as food. The ingestion of a broth made from its rhizome improves lactation, and young fronds of this fern are boiled and eaten with rice by the locals. Nevertheless, its chemical profile is far from being established. The present work aims to establish the chemical profile of both rhizomes and leaves n-hexane extracts by Gas Chromatography- Mass Spectrometry (GC-MS). The results showed the leaves richness in fatty acids with interesting nutritional values (ω-6/ω-3 = 0.68, AI = 0.59, TI = 0.30), being linolenic acid (253.71 ± 0.93 mg/g dry leaves) and palmitic acid (237.27 ± 0.59 mg/g dry leaves) the significant compounds in the extract. Whereas the rhizome extract is mostly rich in terpenoids, such as steroid, cycloartane, and hopanoid derivatives, being hop-16-ene (166.45 ± 0.53 mg/g dry rhizome) and β-sitosterol (50.76 ± 0.11 mg/g dry rhizome) the major compounds. Several compounds are reported for the first time in the species, and the data herein reported contributes to confirming the species nutritional value.

Antioxidant and tyrosinase inhibition activity of the fertile fronds and rhizomes of three different Drynaria species

Background

For generations, the rhizomes of Drynaria ferns have been used as traditional medicine in Asia. Despite this, the bioactivities of Drynaria rhizomes and leaves have rarely been studied scientifically.

Methods

This study evaluates the antioxidant properties of the methanolic extracts of the fertile fronds and rhizomes from three species in this genus: Drynaria quercifolia, Drynaria rigidula and Drynaria sparsisora. The phenolic and flavonoid contents of the samples were respectively quantified with the total phenolic content (TPC) and total flavonoid content (TFC) assays, while the antioxidant activities were determined via measuring the DPPH radical scavenging activity (FRS), ferric reducing power (FRP), ferrous ion chelating (FIC) activity and lipid peroxidation inhibition (LPI). The tyrosinase inhibition activity of all three species was also reported.

Results

The fertile fronds of D. quercifolia were found to exhibit the highest overall TPC (2939 ± 469 mg GAE/100 g) and antioxidant activity amongst all the samples, and the fertile fronds of D. quercifolia and D. rigidula exhibited superior TPC and FRP compared to their rhizomes, despite only the latter being widely used in traditional medicine. The fronds of D. quercifolia had high tyrosinase inhibition activity (56.6 ± 5.0 %), but most of the Drynaria extracts showed unexpected tyrosinase enhancement instead, particularly for D. sparsisora’s fronds.

Conclusion

The high bioactivity of the fertile fronds in the fern species indicate that there is value in further research on the fronds of ferns which are commonly used mostly, or only, for their rhizomes.