Evaluation of Antioxidant and Antibacterial Activities of Phelipanche ramosa (L.) Pomel Extracts

Phelipanche ramosa (L.) Pomel (syn. Orobanche ramosa L.) is a holoparasitic plant that poses significant threats to various crops due to its wide host range. In this study, the antibacterial and antioxidant properties of P. ramosa extracts obtained using different solvents (ethanol, water, ethyl acetate, and diethyl ether) were evaluated. Antibacterial activity was assessed against Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Pseudomonas aeruginosa using the microplate dilution method to determine minimum inhibitory concentration (MIC) values. Ethanol and ethyl acetate extracts showed the strongest antibacterial activity with MIC values in the range of 125–250 µg/mL, while diethyl ether extract exhibited weaker activity compared to other solvents (250–500 µg/mL). Antioxidant capacity was measured via the DPPH radical scavenging method and expressed as IC₅₀ values. Ethanol extract had the highest antioxidant potential (IC₅₀ 27.5 µg/mL) and the highest total phenolic content (11.7 µg GAE/mL), indicating a strong correlation between phenolic content and antioxidant activity. In contrast, the diethyl ether extract showed the lowest antioxidant activity (IC₅₀ 660.4 µg/mL) and phenolic content (0.57 µg GAE/mL). Although no prior studies were found on the direct antibacterial activity of P. ramosa, similar effects have been reported in related Orobanche species. The findings suggest that P. ramosa, particularly ethanol and ethyl acetate extracts, holds potential as a natural source of antibacterial and antioxidant agents due to its rich phenolic composition.