Phytochemical screening, antioxidant and antibacterial activities of ethanol extracts of Asparagus suaveolens aerial parts

Abstract

This study was aimed at investigating the phytochemical constituents, antioxidant activities and antibacterial activities of Asparagus suaveolens (A. suaveolens) aerial parts. Antioxidant properties were assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, hydrogen peroxide scavenging assay and reducing power assay. Antibacterial activity of the extract was assessed by micro-dilution method and 2008 WHO Neisseria gonorrhoea (N. gonorrhoea) reference strains were used for this purpose. Qualitative phytochemical analysis showed the presence of alkaloids, saponins, flavonoids, glycosides, anthraquinones, terpenoids and steroids, reducing sugar, proteins and coumarins. An effective free radical scavenging activity of 71% was observed for chloroform fraction at 2.5mg/mL. Butan-1-ol fraction had 79% inhibition of hydrogen peroxide and 55% reducing power at 2.0mg/mL compared to all other fractions but less than the standards. The n-hexane fraction had moderate growth inhibition against F, O and P 2008 WHO N. gonorrhoea reference strains with MIC values of 1.3mg/mL, 0.12mg/mL and 1.63mg/mL, respectively. The MBC values of the same fraction had moderate activities against the same strains. This promising anti-N. gonorrhoea properties of A. suaveolens aerial parts observed confirms its traditional use in the treatment of gonorrhoea infections by Bolahlakgomo Village commuters of the Limpopo Province, South Africa.