Study natural dye from tuber of Purple Yam (Dioscorea alata) for biological stain and cosmetic colourant

Background : Nowadays, the use of eco-friendly, non-hazardous and non-allergenic natural dyes are truly important due to the increasing of environmental awareness to avoid the usage of hazardous synthetic dyes.

Objectives: To investigate the ability of pigment extracted from tuber Dioscorea alata for possible application as biological stain and cosmetic colourant.

Method: Purple coloured pigment from tuber of Dioscorea alata was extracted with ethanol and solvent was removed using rotary evaporator. The purple coloured pigment was used to stain epidermal cell of Allium cepa and human epithelial cheek cell and were observed under light microscope to reveal the photomicrographs of Allium cepa and human epithelial cheek cell. These were compared with methylene blue staining on Allium cepa and human epithelial cheek cell. The purple coloured pigment also used to glycerine soap as cosmetice colourant.

Results: The purple coloured pigment was unable to stain epidermal cell of Allium cepa and human epithelial cheek cell with purple colour. Glycerine soap which inserted with 5% (w/v), 2.5 % (w/v) and 1.25% (w/v) was coloured with blue, slightly blue black and dark blue black. However, the colour was faded over time.

Conclusion: The purple coloured pigment from tuber of Dioscorea alata has good potential for cosmetic colourants, however it did not suitable to be used as biological stain.