Gromwell-red colourant

This plant extract is obtained from the root of a traditional East Asian medicinal plant. It contains red-purple naphthoquinone pigments, mainly shikonin and its derivatives. As well as providing colour, it offers antioxidant and anti-inflammatory properties. It is more soluble in oils, and its shade changes depending on the formulation's pH, exposure to light and oxidation state.

Gromwell-red colourant provides a natural red to purple tone and may also reduce inflammatory signalling and support the recovery of dry skin. Shikonin affects several enzymes and inflammatory mediators, but at higher doses it can be highly biologically active. The ingredient is therefore used with caution and should not be regarded simply as a harmless plant-based colourant.

It is particularly suitable for balms and oil-based products for dry, mature or irritated skin. For sensitive skin, a low concentration and a patch test are recommended. Use on acutely inflamed skin, during pregnancy or on children requires extra caution and assessment by a safety assessor. It may stain skin, fabrics and packaging.

Cosmetic formulations containing Lithospermum erythrorhizon root extract have been shown to improve hydration and reduce transepidermal water loss in humans, which was associated with protection of the stratum corneum (International Journal of Cosmetic Science, 2008). The study assessed complete formulations, so the result cannot be attributed to the pigment alone.

It is used at low levels depending on its colouring strength and shikonin content. It must be protected from light and oxidation, and its colour stability must be monitored at the target pH. Before use, toxicological data from the supplier are required, along with a check that the intended use is legally permitted.

The effects of plant extracts can vary depending on the plant species, the part used, the solvent and the levels of marker compounds. Two raw materials with similar names may therefore not be interchangeable. A reputable supplier provides details of the extraction method, microbiological purity and standardisation. It is also advisable to monitor the colour, scent and stability of the finished product, as natural origin does not automatically mean there is no risk of irritation. A patch test on a small area is therefore sensible too.