Phytochemical analysis, antimicrobial, antioxidant and enzyme inhibitory activities of ethanolic extract of Centaurea solstitialis L. and its different fractions

Abstract

Resistance to conventional antimicrobial regimes is one of the issues of concern in healthcare and it drives the need for development of new antimicrobial agents. Medicinal plants, as rich source of biochemical and bioactive compounds, serve as potential source for new drugs. Here, we evaluated the ethanolic extract of Centaurea solstitialis L. and its different fractions (n-hexane, choloroform and n-butanol soluble fraction) for antimicrobial, antioxidant and enzymes inhibitory activities. Antibacterial activity against two Gram-positive and three Gram-negative bacteria species were determined by using agar well diffusion and 96-wells microplate methods. Similarly, antifungal activity against two fungal strains was also evaluated by agar well diffusion method. Antioxidant activity analyzed by measuring the scavenging activity of DPPH radicals and acetylcholinesterase, butrylcholinesterase and chymotrypsin inhibitory activity was determined at 10 µg/mL and 1.0 mg/mL concentrations. Results revealed that the ethanolic extract of C. solstitialis and its different fractions possesses significant (P<0.05) antibacterial activity and effective against fungi Aspergillus niger and Macrophomina phaseolina. Significant (P<0.05) DPPH scavenging activity (88.52±0.23%) among all fractions was noted. n-Butanol fraction showed significant acetyl-cholinesterase (78.55±0.76%) and butrylcholinesterase inhibitory activity (78.1±0.41%) with IC50 values of 54.6±0.39 µg/mL and 211.9±0.15 µg/mL, respectively. Maximum chymotrypsin inhibition activity was shown by crude ethanolic extract (87.76±1.17) with IC50 value of 38.23±0.75 µg/mL. It is concluded that C. solstitialis extract and its fractions possess significant antimicrobial, antioxidant and enzyme inhibitory activity.