Composition, antioxidant and chemotherapeutic properties of the essential oils from two Origanum species growing in Pakistan

ABSTRACT

The GC-MS analyses of Origanum majorana L. (OME) and Origanum vulgare L. (OVE), Lamiaceae, essential oils helped identification of 39 (96.4 percent of the total oils) and 43 (92.9 percent of the total oils) components, respectively. The major constituents of OME were terpinene-4-ol (20.9 percent), linalool (15.7 percent), linalyl-acetate (13.9 percent), limonene (13.4 percent) and α-terpineol (8.57 percent), whereas, thymol (21.6 percent), carvacrol (18.8 percent), o-cymene (13.5 percent) and α-terpineol (8.57 percent) were the main components of OVE. In the disc diffusion and the resazurin microtitre assays, OME showed better antibacterial activity than OVE with larger zones of inhibition (16.5-27.0 mm) and smaller MIC (40.9-1250.3 μg/mL) against the tested bacterial strains. Only OVE displayed anti-heme biocrystallization activity with an IC50 at 0.04 mg/mL. In the DPPH assay, OVE showed better radical-scavenging activity than OME (IC50=65.5 versus 89.2 μg/mL) and both OME and OVE inhibited lionleic acid oxidation. However, in the bleaching β-carotene assay, OVE exhibited better antioxidant activity than OME. In the MTT assay, OME was more cytotoxic than OVE against different cancer cell types, such as MCF-7, LNCaP and NIH-3T3, with IC50s of 70.0, 85.3 and 300.5 μg/mL, respectively. Overall, some components of OME and OVE may have antiparasitic and chemotherapeutic activity.