Abstract

ANTIOXIDANT, ANTIMICROBIAL AND CYTOTOXIC CHARACTERISTICS OF A BIOACTIVE COMPOUND ISOLATED FROM THE AERIAL PART OF DICKSONIA ANTARCTICA LABB.

Sudip Regmi*, Suraj Adhikari and Sandesh Panthi

Abstract

The ethanolic extract of Dicksonia antartica Labb leaves was extracted in order to explore and evaluate the pharmacological value in terms of antioxidant property, antimicrobial potential, anthelmintic activity and cytotoxic activity on the basis of brine shrimp lethality bioassay, which could provide reference to future first line investigation. The gummy concentrate obtained from ethanol extraction was designated as crude extract with a yield of 18.8%. The extract exhibited a significant inhibition of DPPH radical scavenging activity with IC50 of 54.78 μg/ml. Total phenolic content of extract was 7.1 mgGAE/g, total tannin content was 4.33 mgGAE/g. The reducing power of extract revealed strong reducing power in concentration dependent manner. The total flavoid content of extract was 41.93 mgQE/g. Ferric reducing antioxidant power of extract was 25.56 μg/ml. Scavanging activity of extract in term of hydrogen peroxide, hydroxyl ion, superoxide radical and nitric oxide were 66.20 μg/ml, 125.88 μg/ml, 135.49 μg/ml and 41.18 μg/ml respectively. Extract displayed broad spectrum antibacterial activity against Staphylococcus aureus, Vibrio cholerae and Shigella dysenteriae and also showed mild activity against Escherichia coli, Staphylococcus epidermidis, and Proteus species. Ethanol extract also possessed anthelmintic activity. Extract at higher concentration (50 mg/ml) is more effective against Paramphistomum cervi. Increased mortality rate of brine shrimp with increased sample concentration demonstrated an approximate linear correlation between them. Cytotoxicity result also correlates the phytochemical component present. The result showed that the extract has some potential bioactivities which require further investigations to isolate bioactive compounds and to identify its underlying mechanisms.

Keywords: Antioxidant, DPPH, Antimicrobial, Dicksonia antartica Labb, Cytotoxicity.