Objective: The study was aimed to evaluate polyphenolic composition and antioxidant properties of methanol extract of rhizome of Drynaria quercifolia (L.)Â Sm.
Methods: In this study, assessment of total phenolic and flavonoid contents were performed using Foiln-Ciocalteu and Aluminium chloride methods respectively. Antioxidant capacity of crude methanolic extract of rhizome of D. quercifolia were examined using established 1,1 – diphenyl – 2-picrylhydrazyl stable free radical (DPPH∙) assay, hydroxyl ion radicals (Ë™OH), nitric oxide (NO), hydrogen peroxide (H2O2)and 2, 2'-Azinobis (3-ethylbenzothiazoline sulphonic acid) ABTS•+ scavenging assays.Â
Results: The extract yielded total phenolic content (TP) of 240 ± 0.01 mg gallic acid equivalents (GAE)/100g of fresh mass (FM) and total flavonoid content (TF) of 150 ± 0.02 mg quercetin equivalents (QE)/100g of fresh mass (FM). The extract of D. quercifolia rhizome exhibited remarkable scavenging capacity towards DPPH∙ (EC50 18.54 ±0.70 µg mL-1), ˙OH (EC50 37.60±0.41 µg mL-1) NO (EC50 42.40 µg mL-1), H2O2 (EC50 32.80±1.89 µg mL-1) and ABTS•+ (EC50 29.80 ±0.70 µg mL-1). The antioxidant capacities of the extract were comparable and stronger than that of the antioxidant standard, butyl hydroxy toluene (BHT). The findings were also comparable with antioxidant properties of other medicinal ferns which are discussed in the study.
Conclusion: Significant and positive correlations (R2 0.999-0.862) were observed between polyphenolic contents and the antioxidant capacities, indicating that the phenolics were major contributors of the antioxidant property. Thus, the methanol extract from the rhizome of D. quercifolia indicated the existence of strong antioxidants and it can be used as tonic
