What is it?
An extract of the seeds of Tephrosia purpurea, a much-branched perennial herb in the legume family that grows abundantly in parts of India and is an important plant in Ayurvedic medicine. In English it is called purple tephrosia, wild indigo or fish poison. In cosmetics the seed extract is listed as a skin-conditioning ingredient.
Key information
- Purple tephrosia seeds contain tephrosin and deguelin, which belong to the rotenoids, the natural insecticides of the Tephrosia genus.
- The plant's roots and seeds have insecticidal and fish-killing properties, which is where the name fish poison comes from.
- We found no published data on how much of these rotenoids, if any, the cosmetic seed extract contains.
- We found no safety assessment of the seed extract by the Cosmetic Ingredient Review or the EU's Scientific Committee on Consumer Safety.
More information
Tephrosia purpurea grows up to about 80 cm tall, with red or purple flowers and slightly curved pods that hold 5 to 10 seeds. In India it is grown as a green manure in rice paddies. Its leaves, roots and seeds contain the flavonoid quercetin, and a flavanone called purpurin has been isolated from the seeds.
The same leaves, roots and seeds also contain tephrosin and deguelin, and the roots contain rotenone. These rotenoids are why Tephrosia extracts have long been used as botanical pesticides, and why the roots and seeds are described as insecticidal and piscicidal (fish-killing). The plant has been reported to poison livestock in Australia. Rotenone itself comes from the roots of Tephrosia, Derris and Lonchocarpus plants. In its 2007 review, the U.S. Environmental Protection Agency kept rotenone only for killing fish, classified as a Restricted Use Pesticide because of its acute inhalation, oral and aquatic toxicity, and noted animal studies at very high doses that produced Parkinson’s disease-like symptoms.
Reality check: none of this shows that the cosmetic seed extract is harmful, and a skin-care ingredient is not a pesticide. But we found no published data on the extract’s rotenoid content, no skin irritation or allergy testing, and no safety assessment by the Cosmetic Ingredient Review (CIR) or the EU’s Scientific Committee on Consumer Safety. Until that information exists, the evidence does not support calling it either safe or unsafe. On labels it appears as Tephrosia Purpurea Seed Extract.
Sources: Asian Journal of Research in Chemistry (2011): Studies on standardization of Tephrosia purpurea Linn, an important Ayurvedic drug; Journal of Applied Pharmaceutical Science (2019): Phytochemical and pharmacological aspects of Tephrosia genus; Toxins (2022): Variation in rotenone and deguelin contents among strains across four Tephrosia species; U.S. EPA: Reregistration Eligibility Decision for Rotenone (2007)
