Staining of Parasitic Helminths by Extracts of , and : An Approach to Herbal Dyes.

Background: Although carmine, as a synthetic dye, is the major substance for staining helminths, it may impose some adverse effects on human health. In the present study, we evaluated the aqueous extracts of onion () skin, walnut () husk, and madder () roots as potential herbal dyes for staining parasitic helminths.

Methods: Aqueous solutions (5%, 10% and 20%, ) of each herbal prepared from dried and powdered husk of walnut, skins of red onion, and madder roots in distilled water. Parasitic helminths including spp., , protoscolices, spp., and were stained by different concentrations of herbal dyes according to carmine staining method. The structural clarity and quality of stained internal organs of the helminths such as suckers, intestine, and reproductive systems were scored by semi-quantitative evaluation in comparison with carmine stained samples.

Results: The optimum concentrations of extracts for helminths staining were 10% () of and , and 20% () of with final scores of 3.1, 3 and 2.8, respectively. In general, and extracts showed higher quality in staining Platyhelminthes, while extract presented relatively higher quality in staining Nematoda.

Conclusion: Considering proper quality of , and extracts in staining the helminths, they may be safe, eco-friendly, and inexpensive alternatives to carmine dye.