Assessment of Antibacterial and Antioxidant Properties of Ethanol and Aqueous Extracts of Euphorbia polycnemoides Aerial Parts

Abstract

The search for effective and safer alternatives to synthetic antimicrobial agents has intensified due to rising concerns over antibiotic resistance. Herbal medicines, rich in bioactive compounds, have emerged as promising candidates due to their antimicrobial and antioxidant properties. This study assessed the antibacterial and antioxidant activities of ethanol and aqueous extracts from the aerial parts of Euphorbia polycnemoides. Antibacterial efficacy was evaluated against Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, and Enterococcus faecalis using agar well diffusion and minimum inhibitory concentration (MIC) assays. The ethanol extract exhibited strong antibacterial activity, particularly against S. aureus (20.0±0.0 mm at 500 mg/mL) and K. pneumoniae (19.0±1.0 mm), with MIC values generally lower than those of the aqueous extract. Antioxidant potential was assessed using FRAP, DPPH, nitric oxide, lipid peroxide, and hydrogen peroxide scavenging assays. Both extracts demonstrated dose-dependent radical scavenging activities, with the aqueous extract showing higher performance in DPPH (75.79±0.66% at 100 µg/mL) and lipid peroxide (66.56±0.47%) assays. Phytochemical screening revealed the presence of flavonoids, tannins, alkaloids, phenols, and saponins in both extracts, supporting their bioactivity. Quantitative analysis indicated higher tannin and reducing sugar contents in the aqueous extract, while the ethanol extract had higher phenol, alkaloid, and flavonoid contents. GC-MS analysis identified several antimicrobial and antioxidant compounds such as monopalmitin, palmitic acid, phytol, terpineol, and isoborneol. These findings suggest that E. polycnemoides aerial part extracts, particularly ethanol-based preparations, hold promising potential as natural antibacterial and antioxidant agents, supporting their possible application in the development of phytotherapeutic drugs.

Keywords: Euphorbia polycnemoides, antimicrobial agents, antioxidant, phytochemical screening, GC-MS analysis