Phytochemical diversity of Cymbopogon citratus Stapf volatile compounds and evaluation of their biological properties

The current work aimed to investigate the chemical composition, antioxidant potential, enzymatic inhibition, and antimicrobial efficacy of Cymbopogon citratus Stapf essential oil (CCEO) sourced from Settat province, Morocco. We employed a comprehensive suite of analytical and biological assays to evaluate CCEO. The chemical composition was analyzed via GC-MS. Antioxidant properties were assessed through multiple complementary methods, including DPPH and ABTS radical scavenging, Ferric Reducing Antioxidant Power (FRAP), and Total Antioxidant Capacity (TAC) assays, with BHT as reference standard. Dermoprotective activity was evaluated through tyrosinase inhibition using the l-DOPA test, while anti-diabetic potential was measured via α-amylase inhibition using the DNSA method. The antibacterial activity was investigated through minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) determinations against both Gram-positive and Gram-negative bacterial strains, utilizing a broth microdilution method with resazurin as a growth indicator. The CCEO was found to contain 15 compounds, with the major constituents being geranial (43.02 %), neral (32.4 %), geraniol (4.7), and β-myrcene (4.3 %). The oil exhibited moderate antioxidant activity, with DPPH and ABTS radical scavenging IC₅₀ values of 106.2 ± 3.7 μg/mL and 98.3 ± 4.4 μg/mL, respectively. Its ferric reducing antioxidant power (FRAP) gave an EC₅₀ of 265.8 ± 3.5 μg/mL. The total antioxidant capacity was 495.7 ± 15.4 mg AAE/g EO. Interestingly, the CCEO demonstrated moderate inhibitory effects on key enzymes. It inhibited tyrosinase by 43.3 % at a concentration of 12.8 mg/mL and α-amylase by 24.8 % at a concentration of 11.1 mg/mL. Furthermore, the essential oil displayed promising antibacterial properties. The minimum inhibitory concentrations (MICs) against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Listeria monocytogenes were 0.5 %, 0.5 %, 0.25 %, and 0.25 % (v/v), respectively. The minimum bactericidal concentrations (MBCs) ranged from 0.25 to 1 % (v/v), all lower than the standard antibiotic chloramphenicol. These findings suggest that CCEO is a promising source of natural bioactive compounds with potential applications in healthcare, cosmetics, and food industries. The comprehensive characterization of its chemical profile, antioxidant, enzymatic, and antimicrobial activities provides a foundation for further exploration and utilization of this essential oil.