In-vitro antioxidant and antimicrobial activity of Bougainvillea glabra flower

Abstract

The aim of the present study is to assess the phytochemical nature, antioxidant and antimicrobial activities of methanolic extract of Bougainvillea glabra flower. Antioxidants play an important role in protecting cellular damage by reactive oxygen species. The fractions of the flower extract were screened for antioxidant activities using DPPH radical scavenging activity, reducing power assay, total antioxidant capacity and reduction of ferric ions by o-phenanthroline color method. Antimicrobial activities of different solvent fractions were tested against gram positive and gram negative bacterial strains by observing the zone of inhibition using disc diffusion method, where elmipenem (10 μg disc-1) was used as the standard. The bacterial strains used in the study were Staphylococcus aureus, Bacilluscereus, Escherichia coiiand Pseudomonasaeruginosa. The extracts revealed the presence of phytochemicals. Almost all three fractions exhibited remarkable antioxidant and antimicrobial activity in terms of all the assays tested. Water fraction showed DPPH radical scavenging activity with IC50 value of 135.73 μg mL-1. Not surprisingly, the n-hexane fraction showed excellent antioxidant activity for reduction of ferric ions by o-phenanthroline color method. All three types of fractions showed inhibitory effect against all tested bacteria except P aeruginosa. These findings indicate compounds isolated from carbon tetrachloride and water fractions possess pharmacological properties and potential to develop natural compounds based pharmaceutical products. All fractions of B. glabrawere found to be the most effective free radical quencher, a potent source of natural antioxidants and antimicrobial agents, thus justifying their traditional use in green therapeutics.