The current study provides the first comprehensive assessment of rose geranium oil (commercially referred to as a hybrid of Pelargonium graveolens L'Hér.) extracted from plants cultivated in Lebanon. The chemical composition was deciphered by GC–MS, and citronellol (30.5%), citronellyl formate (15.9%), trans-geraniol (12.8%), linalool (8.6%), and isomenthone (8.0%) were the major constituents. The oil composition most closely resembles rose geranium oil from Egypt. The essential oil exhibited weak antioxidant activity with only 16% inhibition achieved at 2.2 mg/mL in the DPPH radical-scavenging assay. The antiinflammatory activity of the essential oil was evaluated in three different setups, namely albumin denaturation, heat induced hemolysis, and nitric oxide scavenging activity, where a dose-dependent response was observed in the different assays. Assessment of the antibacterial activity of the essential oil revealed a bactericidal effect against the tested bacterial strains. The essential oil showed good cytotoxicity against HCT 116 human colon cancer cells with an IC50 value of 74 µg/mL as determined by the MTT cell viability assay. In the acetylcholinesterase (AChE) inhibition assay, the oil displayed a dose-dependent inhibition of AChE enzyme with an IC50 value of 10.5 mg/mL, thus highlighting the antiAlzheimer's protection potential of the extract. Finally, no significant hemolytic activity was observed even at the highest tested concentration (5 mg/mL). In conclusion, rose geranium oil produced in Lebanon demonstrated promising biological properties, and its cultivation for medicinal and industrial applications is highly recommended.
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