In vitro comparative study of Bougainvillea spectabilis “stand” leaves and Bougainvillea variegata leaves in terms of phytochemicals and antimicrobial activity

Abstract

Abstract Aim To study the qualitative analysis of phytochemicals and antibacterial activity of the ethanolic and methanolic extracts of Bougainvillea spectabilis and Bougainvillea variegata leaves.

Methods Phytochemical constituents were determined qualitatively by the Harborne method, while antimicrobial activities were determined by measuring the zone of inhibition on Mueller Hinton Agar.

Results The maximum inhibitory effects were obtained against the Gram positive microbe Staphylococcus aureus for the methanolic extracts of both B. spectabilis [(28.54 ± 0.18) mm] and B. variegata [(21.97 ± 0.06) mm]. The Gram negative microbes Proteus vulgaris [(16.00 ± 0.15) mm] and Serratia marcescens [(16.00 ± 0.06) mm] gave maximum inhibitory effects for the ethanolic extracts of B. variegata, while Salmonella typhimurium [(17.26 ± 0.12) mm] gave a maximum zone of inhibition for the methanolic extract of B. spectabilis. No inhibitory effects were observed for the extracts of B. spectabilis or B. variegate against Enterococcus faecalis, Vibro cholera or Klebsiella pneumoniae.