Toxicología ambiental y analítica

Determination of Heavy Metals and Other Toxic Ingredients in Henna (Lawsonia inermis)

Abstract

Sahar Younes Ibrahim, Marwa M Fawzi, Mohammed Gaber Saad and Safaa M Abdel Rahman

Background: The plant Henna (Lawsonia inermis, family Lythraceae) is a naturally grown or cultivated plant allover Africa and Asia. Marketed Henna is a natural powdered material derived from dried and crushed leaves of the plant. Henna is very popular in many parts of Egypt as it is part of the culture and traditions, and it recently became very popular in touristic areas as Sharm El Sheikh-Egypt being used as a tattooing agent. This makes detection of heavy metal content and, other toxic ingredients in Henna marketed in Egypt of crucial importance.

Objective: To investigate heavy metal content and, other toxic ingredients as para-phenylenediamine (PPD) in Black Henna marketed in Egypt.

Methods: Fifteen Black Henna samples were collected randomly from Sharm El Sheikh-Egypt market and, analyzed for metal content by atomic absorption spectrophotometry (ICP-MS) after microwave acid digestion, also the presence of PPD in henna samples was determined qualitatively and quantitatively using High Performance Liquid Chromatography (HPLC).

Results: PPD was detected in all the black henna samples at concentrations ranging between 1.75% and 32.1%, which is higher than that recommended for hair dyes. The mean concentration of some studied metals as Aluminium, Lead, copper, nickel, and zinc were higher than permissible levels for cosmetics in some of the studied samples.

Conclusion: In conclusion, PPD is a common ingredient in black henna dye in the developing world. Physicians must be aware of the potential toxicity of this chemical and of the clinical signs of systemic poisoning. High concentration of some metals as Aluminium, lead, copper, nickel, and zinc might be encountered in some Henna products. Considering popular use of henna, the hazardous cumulative effects of prolonged exposure to low concentrations of such metals, especially in children, cannot be ruled out. Further studies are recommended.