Chemistry of Henna
CHEMISTRY OF HENNA The chemistry of henna (Lawsonia inermis) is very interesting - it is an amalgamation of organic chemistry, natural dyes, and skin chemistry. Let’s break it down simply 1. Source The henna is derived out of the leaves of the plant Lawsonia inermis. Lawsone is the active dye molecule of henna. Chemical name: 2-hydroxy-1,4-naphthoquinone Molecular formula: C₁₀H₆O₃ Form: It is a naphthoquinone analog of anthraquinone-type dyes. 2. Chemistry of Lawsone Functional groups: Hydroxyl group (-OH) Two (carbonyl) C=O groups in quinone ring. This renders lawsone a weak acid and provides the latter with the capacity to develop hydrogen bonds and react with proteins. 3. Mechanism /How Henna stains Skin/Hair When henna paste is applied: The molecules of lawsone permeate the epidermis or hair. They attach themselves to keratin which is the major protein on the hair and skin. It reacts by Michael addition - the quinone group in lawsone reacts with the amino groups...
