Apoptosis-mediated proliferation inhibition of human colon cancer cells by volatile principles of Citrus aurantifolia

Fruits of Citrus aurantifolia were subjected to hydro-distillation using Clevenger type apparatus to obtain volatile oil. Chemical composition of volatile oil was analysed by GC–MS. Twenty-two compounds representing more than 89.5% of the volatile oil were identified. d-limonene (30.13%) and d-dihydrocarvone (30.47%) were found to be the major compounds in the lime volatile oil. This oil showed 78% inhibition of human colon cancer cells (SW-480) with 100 μg/ml concentration at 48 h. Lime volatile oil showed DNA fragmentation and induction of caspase-3 up to 1.8 and 2- folds after 24 h and 48 h, respectively, which may be due to the involvement of apoptosis. Analysis of apoptosis-related protein expression further confirmed apoptosis induction by lime volatile oil. The above results suggested that lime volatile oil has potential benefits in colon cancer prevention. This is the first report, showing the possible mechanism of antiproliferative effect of lime volatile oil for the prevention of colon cancer in cell culture models.