Chemical composition, allelopatic and cytotoxic effects of essential oils of flowering tops and leaves of Crambe orientalis L. from Iran.

Crambe orientalis L. (Brassicaceae), a perennial herb, is indigenous to Iran. The essential oils of flowering tops and leaves of the plant were evaluated by GC-MS. Our results showed that while 2-methyl-5-hexenitrile (19.5%) and benzyl cyanide (16.9%) were the major components of flowering tops oil, the oil of the leaves was dominated by octyl-acetate (54.3%) and butenyl-4-isothiocyanates (22.6%). The oils exhibited modest allelopatic effects on lettuce. The leaf oil showed high-cytotoxic effects against Mc-Coy cell lines, with an RC(50) value of 16 microg mL(-1).