In-vitro antioxidant and antibacterial activities of Xanthium strumarium L. extracts on methicillin-susceptible and methicillin-resistant Staphylococcus aureus

Background and Aims: The excessive and repeated use of antibiotics in medicine has led to the development of antibiotic-resistant microbial strains, including Staphylococcus aureus whose emergence of antibiotic-resistant strains has reduced the number of antibiotics available to treat clinical infections caused by this bacterium. In this study, antioxidant and antimicrobial activities of methanolic extract of Xanthium strumarium L leaves were evaluated on methicillin-susceptible and methicillin-resistant Staphylococcus aureus (MRSA) spp. Materials and Methods: Antiradical and antioxidant activities X. strumarium L. leaf extract were evaluated based on its ability to scavenge the synthetic 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical and by the paired diene method, respectively, whereas the antimicrobial activity was assayed by the disc diffusion method. Statistical Analysis: Data were subjected to analysis of variance following an entirely random design to determine the least significant difference at P < 0.05 using SPSS v. 11.5. Results and Conclusions: The IC50 values of the extract were 0.02 mg/mL and 0.09 mg/mL for the antioxidant and DPPH-scavenging capacity, respectively. X. strumarium extract affected both methicillin-sensitive Staphylococcus aureus and MRSA, though antibacterial activity was more effective on methicillin-susceptible S. aureus spp. The antibacterial and antioxidant activities exhibited by the methanol extract may justify the traditional use of this plant as a folk remedy worldwide.