Lipoxygenase Inhibitory, Antioxidant, and Antimicrobial Activities of Selected Essential Oils

Objective: To evaluate lipoxygenase inhibitory, antioxidant, and antimicrobial activities of selected essential oils. Materials and Methods: Essential oils were obtained by hydro distillation using a Clevenger-type apparatus and oils composition was analyzed by gas chromatography-mass spectrometry. Lipoxygenase inhibitory activity of essential oils was evaluated by lipoxygenase inhibition assay and antioxidant activity by ferric reducing antioxidant power, 2,2-diphenyl-1-picrylhydrazyl and β-carotene-bleaching assay. Antimicrobial activity was determined by agar dilution, broth dilution, and poisoned food method. Results: Lipoxygenase activity was inhibited significantly by Cymbopogon winterianus oil, and the inhibition was 96% at 12.5 μg/ml concentration. Concentration providing 50% inhibition (IC50) value of C. winterinus oil for lipoxygenase inhibitory activity was 3.98 μg/ml. Lipoxygenase inhibition was 56, 58, 60 and 51% by Chamomilla recutita, Mentha arvensis, Cymbopogon martini and Cymbopogon flexuosus oil at 12.5 μg/ml concentration, respectively and IC50 values were in the range of 10-12.2 μg/ml. Among major terpenes components of the oils, lipoxygenase inhibitory activity was highest in the citronellal (IC50 value 1.66 μg/ml) followed by citronellol and citral. The essential oil of Ocimum sanctum exhibited significant reducing potential and antioxidant activity. Antibacterial activity was the highest in C. flexuosus oil while antifungal activity was highest in C. flexuosus and in M. arvensis oil as compared to other oils. Conclusion: C. winterianus oil and its component citronellal with high antilipoxygenase activity are suitable for analgesic and anti-inflammatory purposes. C. flexuosus oil is suitable for checking of food spoilage as well as for dandruff due to high antimicrobial activity. O. sanctum oil can be used as a good source of antioxidants.