Appraisal of phytochemical constituents, antioxidant and antibacterial activities of folkloric Pentanema confertiflorum rootbark extracts

Abstract

BackgroundMedicinal plants have cultural prominence in the management of ailments worldwide. The different organs of Pentanema confertiflorum (hereafter referred as P. confertiflorum) as have been used to ameliorate different diseases in Ethiopia. Thus, this study focused on the qualitative and quantitative phytochemical analysis, antioxidant, and antibacterial screening of P. confertiflorum rootbark solvent fractions. MethodsThe rootbark of P. confertiflorum was successively soaked with petroleum ether, chloroform, and methanol. The total phenolic (TPC), flavonoid (TFC), and alkaloid contents (TAC) of the different crude extracts were determined through Folin-Ciocalteu Reagent (FCR), aluminum chloride colorimetric, and bromocresol green (BCG) assays, respectively. In addition, 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging and ferric-reducing antioxidant power (FRAP) assays were employed to determine the antioxidant activity of crude extracts. Moreover, the antimicrobial activity of the crude extracts was assessed against different bacteria strains via the disc diffusion method. ResultsThe qualitative phytochemical investigation study resonated with the abundance of several secondary metabolites, especially in the methanolic rootbark extract (MRBE). In addition, the MRBE had the highest TPC (76.7 mg GAE/g extracts), TFC (86.89 mg QE/g extracts), and TAC (80.68 mg ATE/g extracts) as compared to petroleum ether and chloroform extracts. Consistent with its TPC, TFC, and TAC, the MRBE demonstrated better antioxidant activity against DPPH radical scavenging (IC50 = 44.53 ppm) and FRAP assays (EC50 = 42.72 ppm). Moreover, all the rootbark extracts induced dose-dependent antibacterial activity against Streptococci pyogenes and Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli. ConclusionsThe preliminary findings suggested the presence of a strong correlation between the folkloric use of P. confertiflorum and its observed antioxidant and antibacterial activity. Rigorous studies on the extracts such as the isolation and characterization of bioactive compounds, and detailed bioactivity and toxicity studies are desirable to bring about safe and effective lead compounds.