Cytotoxic Evaluation of Annatto (Bixa orellana L.) Dye Compared with Orange Red

Abstract

Cytotoxic evaluation of annatto (Bixa orellana L.) seed pulp extract on Allium cepa root tip cells was carried out. The annatto dye was extracted using different solvents viz. alkaline water, ethyl alcohol and chloroform : alcohol mixture (1 : 3). Crude extract evaporated and dry residual powder recovered. The powder was dissolved in water at different concentrations (0.1%, 0.5% and 1%) and was used to treat onion root tips for 12 h and the mitotic behaviour was recorded. The results were compared with a synthetic dye orange red at 2 concentrations (0.05 and 0.1%). Annatto extracts treated cells showed normal mitotic behaviour whereas orange red (0.1% w/v) showed complete arrest of cell division. The synthetic dye at low concentration (0.05% w/v) showed diverse forms of mitotic abnormalities like single or double nuclear lesions, single, double or multiple bridges, metaphase clumping, tropokinensis and chromosome fragments. Cyototoxicity test system based on A. cepa root tips has proved that annatto dye is significantly less toxic compared to its synthetic alternative, orange red.