Screening the phytochemical analysis, biological activity and in vitro gas production parameters of Tunisian lemongrass (Cymbopogon citratus) essential oils.

This study aimed to investigate the biological activity, antioxidant, and antibacterial capacities of Cymbopogon citratus essential oils (CEO), as well as their effects on in vitro rumen fermentation and methane emissions using breed rumen liquor. Eighteen compounds were identified in the leaves, with E-citral (46.44%), Z-citral (39.91%), and geraniol (3.99%) being the principal components. CEO exhibited a higher antiradical capacity (IC50 = 92 µg/ml) compared to the methanol extract (IC50 = 290 µg/ml). Enterococcus faecalis was the most sensitive strain to CEO, showing the largest inhibition zone (IZ = 40 mm). Inclusion of CEO at 5 µL/mL positively affected in vitro fermentation, with optimal values for parameters (V24, VFA, ME, and DMO) at this dose; values decreased at higher concentrations. Methane production decreased significantly with increasing essential oil concentration, with reductions of 21%, 20%, and 18% for 5, 10, and 20 µL/mL doses, respectively. CEO demonstrated greater activity against Gram-positive bacteria and significant antifungal activity against Candida albicans. These findings suggest that C. citratus leaves possess antioxidant, antimicrobial, and antibacterial properties, indicating potential as antiparasitic agents in sheep.