Aloysia citriodora Palau (AC) is commonly known as Lemon Verbena and has been utilized as a medicinal tea in folkloric medicine for the treatment of abdominal spasm, anxiety, and fever. The present investigation aimed to identify the chemical ingredients of AC essential oil (EO) collected from two different locations in Palestine and to assess their antioxidant, antimicrobial, cytotoxic, and cyclooxygenase (COX) inhibitory effects.
Gas chromatography/mass spectroscopy (GC/MS) technique was used to identify the chemical components of the hydro-distilled EO from both regions, while DPPH, MTS, and COX assays were utilized to estimate the antioxidant, cytotoxic, and COX inhibitory activities of the EOs, respectively. Moreover, a broth microdilution assay was used to assess antimicrobial potentials against seven microbial strains.
The GC/MS technique revealed the presence of 17 compounds from the AC collected from the Umm al-Fahm region and 13 compounds from the sample from the Baqa al-Gharbiyye region, while α-citral was the major component of both EOs, representing 47.62 and 43.46%, respectively. The Baqa al-Gharbiyye AC EO exerted more potent antioxidant activity than the Umm al-Fahm EO, with IC50 values of 11.74 ± 0.18 and 35.48 ± 0.14 μg/mL, respectively, while the positive control Trolox had antioxidant IC50 values of 2.45 ± 0.01 μg/mL. Interestingly, both EOs inhibited more potential activity against Methicillin-Resistant Staphylococcus aureus (MRSA) and Proteus vulgaris than Ciprofloxacin and Ampicillin antibiotics and also showed more potent antifungal activity against Candida albicans than Fluconazole. Moreover, the Baqa al-Gharbiyye AC EO had a more potent cytotoxic effect than the Umm al-Fahm EO, with IC50 values of 84.5 ± 0.24 and 33.31 ± 0.01 μg/mL, respectively, compared with Doxorubicin, which had an IC50 dose of 22.01 ± 1.4 μg/mL. The EOs from Baqa al-Gharbiyye showed potent activity against both COX-1 and COX-2 enzymes, with IC50 of 52.93 ± 0.13 and 89.31 ± 0.21 μg/mL, respectively, while the EOs from the Umm al-Fahm region showed weaker activity against these enzymes, with IC50 of 349.99 ± 0.33 and 1326.37 ± 1.13 μg/mL, respectively.
Both characterized EOs have a huge variety of chemical components. The Baqa al-Gharbiyye AC EO has more potent antioxidant and cytotoxic activities than the Umm al-Fahm EO, but both have potential antimicrobial activity against MRSA, P. vulgaris, and C. albicans. These results suggest the use of AC EOs as promising sources of active ingredients in the food, cosmetic, and pharmaceutical industries.