Estimation for Raw Material Plants of a Henna Product Using LC-High Resolution MS and Multivariate Analysis

Area of Science:

• Analytical Chemistry
• Natural Products Chemistry
• Dermatology

Background:

• Henna (Lawsonia inermis) is a natural dye used for hair and body art.
• Commercial henna products may contain blends of Lawsonia inermis, Indigofera tinctoria, and Cassia auriculata.
• Allergic reactions to henna dyes can be caused by additives like p-phenylenediamine or the plant materials themselves.

Purpose of the Study:

• To develop and validate a method for identifying the raw plant materials in commercial henna dye products.
• To analyze commercial henna products available in Japan using advanced analytical techniques.

Main Methods:

• Liquid Chromatography-High Resolution Mass Spectrometry (LC-HRMS) was employed for chemical analysis.
• Multivariate analysis, specifically Principal Component Analysis (PCA), was used to interpret the complex data.
• Seventeen commercial henna product samples were analyzed.

Main Results:

• PCA successfully classified the 17 samples into three distinct groups corresponding to henna, Indigofera tinctoria-dominant blends, and Cassia auriculata.
• Characteristic compounds lawsone, indirubin, and rutin were identified as markers for each group.
• One product labeled as henna was reclassified, suggesting discrepancies between product labels and actual ingredients.

Conclusions:

• LC-HRMS combined with PCA provides an effective method for estimating the raw plant materials in commercial henna dyes.
• The study highlights potential inaccuracies in commercial henna product labeling.
• This analytical approach offers a reliable way to verify the botanical origin of plant-based dyes.