Chemical composition and cytotoxic activities of Rhodomyrtus tomentosa (Aiton) Hassk. essential oil extracted by microwave-assisted hydrodistillation

Rhodomyrtus tomentosa (Aiton) Hassk. has been widely used in traditional medicine; however, limited attention has been paid to its essential oil's chemical profile and biological activities. In this study, essential oil was extracted from fresh leaves of R. tomentosa using microwave-assisted hydrodistillation. The oil yield was 0.72% (v/w), and gas chromatography-mass spectrometry (GC-MS) analysis revealed a composition highly enriched in monoterpene hydrocarbons, with α-pinene comprising approximately 79.73% of the total content. Minor constituents included β-caryophyllene, α-terpineol, and d-limonene. The cytotoxic potential of R. tomentosa essential oil (RtEO) was evaluated against three human cancer cell lines: breast adenocarcinoma (MCF-7), epidermoid carcinoma (KB), and lung carcinoma (A549) using the WST-1 assay. RtEO exhibited significant dose-dependent cytotoxicity, with IC50 values of 14.30 µg/mL, 19.91 µg/mL, and 20.63 µg/mL, respectively. These results suggest that RtEO possesses promising broad-spectrum anticancer activity, warranting further investigation as a potential natural source of bioactive compounds for cancer therapy.