Phytochemical Analysis of Caesalpinia Gilliesii Fruit Extracts by GC-MS and Evaluating Antioxidant and Antibacterial Activities

This work provides the first detailed exploration of the phytochemical composition and biological properties of Caesalpinia gilliesii fruits cultivated in Egypt. Essential oils were extracted and analyzed by gas chromatography–mass spectrometry (GC–MS), which led to the identification of 28 constituents accounting for 93.4% of the total oil. Major compounds included α-terpinene, α-copaene, α-cadinol, and β-eudesmol, all known for their potent biological activities. Successive solvent extractions (hexane, petroleum ether, chloroform, ethyl acetate, and methanol) were performed to assess the phytochemical profiles, antioxidant capacities, and antibacterial potentials of the fruit extracts. Quantitative assays revealed that methanol and ethyl acetate extracts contained the highest concentrations of phenolics and flavonoids, which correlated with strong antioxidant activity (total antioxidant activity [TAA] up to 75.3%) and low IC₅₀ values (26.4 μg/mL). Antibacterial evaluation showed that the methanolic and ethyl acetate extracts possessed pronounced growth-inhibitory and bactericidal properties, mainly against the Gram-positive strains Staphylococcus aureus and Staphylococcus epidermidis, whereas the essential oil displayed comparatively moderate antimicrobial efficacy. Notably, the Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of the methanol extract were comparable to those of standard antibiotics. Overall, this study provides the first detailed GC-MS-based chemical profile and biological evaluation of C. gilliesii fruit extracts, underscoring their potential as a novel natural source of antioxidant and antibacterial agents with promising applications in pharmaceutical and nutraceutical fields.