Phytochemical evaluation of 96% ethanol extract of Nigella sativa and its antibacterial activity against Staphylococcus aureus

Introduction: Antibiotic resistance has been recognized as a major concern within the field of dermatology. Skin infections are frequently caused by Staphylococcus aureus, including methicillin-resistant strains (MRSA), which often display resistance to standard antibiotic therapies. Nigella sativa (black cumin) has long been utilized in traditional medicine due to its antimicrobial activity, primarily attributed to its main bioactive component, thymoquinone (TQ). In this study, the antibacterial potential of N. sativa extract obtained using 96% ethanol was assessed to investigate its viability as an alternative antimicrobial agent. Methods: A descriptive experimental approach was employed in this study. The 96% ethanol extract of black cumin seeds (BCS) was analyzed for its phytochemical constituents, and the thymoquinone content was quantified using high-performance liquid chromatography (HPLC). The antibacterial efficacy of the extract was evaluated against S. aureus through minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays. Result: The extract yielded 14.31% and phytochemical screening confirmed the presence of flavonoids, alkaloids, saponins, and steroids. The TQ content was 1.27%. It inhibited S. aureus with a MIC of 50 mg/mL, while MBC was undetectable, indicating a bacteriostatic effect. Conclusion: Although N. sativa extract demonstrated antimicrobial activity, its effectiveness was lower than conventional antibiotics. Further research is required to optimize extraction methods and evaluate synergistic effects with antibiotics for potential dermatological applications.