Phytochemical constituents and therapeutic effects of the essential oil of rose geranium (Pelargonium hybrid) cultivated in Lebanon

Abstract

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.