Total phenolic content, antioxidant activity, GC-MS characterization, and antimicrobial activity of leaf and flower extracts of Porophyllum ruderale

Abstract

The entire aerial part of Porophyllum ruderale has been reported to possess biological activities. No study has been undertaken to compare the biological activities of the aerial parts. This study aimed to compare the total phenolic content (TPC) and the biological activities of ethanolic extracts of leaves and flowers of Porophyllum ruderale. TPC was measured using the Folin-Ciocalteu method, antioxidant activity was determined using the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay, and antimicrobial activity was estimated by measuring the minimum inhibitory concentration (MIC) of the flower and leaf extract tested against test microorganisms. In addition, the interaction effects of combining the extracts with standard antimicrobial drugs were also evaluated. TPC of the flower and leaf extracts of Porophyllum ruderale were 381.00 ± 27.00 and 328.33 ± 49.89 mg GAE/g, respectively. The flower extract recorded significantly higher DPPH antioxidant activity (80.16 ± 5.54 %) than the leaf extract (29.74 ± 4.15 %). GC-MS analysis revealed that the major compounds found in the flower extract included 5-Hydroxymethylfurfural (65.38 %), n-hexadecanoic acid (10.04 %), phytol (10.36 %) and alpha-tocopherol (10.21 %) while 5-hydroxymethylfurfural (33.55 %), phytol (22.31), and alpha-tocopherol (24.93 %) were present in the leaf extracts. The MIC of the flower extract ranged between 0.39 and 12.50 mg/mL, while the MIC of the leaf extract ranged between 0.39 and 25.00 mg/mL. The leaf extracts against antibacterial drugs showed predominantly synergistic effects, while that of the flower extract showed either synergistic, additive, or no difference effects. Thus, there are differences in their biological activity, but both extracts showed the potential to be used as antimicrobial agents, either alone or in combination with standard antimicrobial drugs.