Top cosmetic chemistry resources list this ingredient as merely a skin conditioner. Chanel skincare lines use purple sweet potato root extract. Studies on this ingredient have only been done internally (see source) and Chanel doesn’t share its research on topical use (if there is any). The information below relates to sweet potato as a source of nutrition, not in skincare creams.
The root and skin contain most of the studied medicinal components. High levels of polyphenols, such as anthocyanins and phenolic acids (eg, caffeic acid), have been isolated from sweet potato. Chlorogenic, dicaffeoylquinic, and tricaffeoylquinic acids are derivatives of caffeoylquinic acid that protect the root from fungal diseases and have potential cancer chemoprotective effects. The numerous acylated anthocyanins are the major color constituents in the storage roots and are important in the plant’s use in diabetes. Sesquiterpenoids include 6-myoporol and ipomeamarone. Structural properties of the anthocyanins important for bioactivity include phenolic esters of the sugar, presence of 2 hydroxyl groups on the aromatic ring, and the presence of an unsaturated alkyl chain in the acylated moiety.
The plant’s antioxidant activity is associated with its alpha-tocopherol content, which is the most common form of vitamin E, and comprises 25 mg per 100 g of sweet potato shoots. The 2 storage proteins, sporamins A and B, account for more than 80% of the total protein isolated from the roots of sweet potato.