From sugarcane to skin: Lignin as a multifunctional ingredient for cosmetic application

Lignin has been suggested as a promising candidate for cosmetic applications due to its remarkable potential to absorb ultraviolet rays and distinctive antioxidant activity. This study aims at evaluating the performance of lignin from sugarcane bagasse (SCB) as natural UV blocker, antioxidant, and pigment. Lignin was extracted from SCB, characterized and incorporated into a blemish balm (BB) cream. The biological potential, concretely, in vitro and in vivo sun protection factor (SPF) and in vitro UVA-PF, and safety were assessed. A high-purity SCB lignin (>92 %) was obtained by a mild alkaline extraction process. The results of cytotoxicity, mutagenicity, skin sensitization and in vivo acute cutaneous irritation demonstrated that SCB lignin is safe for topical applications. Lignin showed capacity to scavenge both ABTS and DPPH radicals, which were preserved after its incorporation into the cosmetic formulation. Notable results were achieved in terms of in vitro and in vivo SPF of 9.5 +/- 2.9 and 9.6 +/- 0.8, respectively. Furthermore, the tested lignin-based BB cream revealed a broad-spectrum UV protection (critical wavelength of 378 +/- 0.5 nm). These results suggest SCB lignin as multifunctional and safe ingredient for use in cosmetic products.