Evaluation of cytotoxicity of 5-n-alkylresorcinol homologs and fraction on mouse fibroblast cell line L929

Cytotoxic effect of natural 5-n-alkylresorcinol fraction, individual homologs and some related compounds (resorcinol, orcinol and olivetol) was tested in vitro against mouse fibroblast cell line L929 in terms of their safety for use according to PN-EN ISO 10993-5:2009 method. Alkylresorcinol-rich fraction and five known individual alkylresorcinol homologs (C17:0, C19:0 C21:0, C23:0 and C25:0) were obtained from spelt (Triticum spelta L.) bran. The structures of these compounds were elucidated and confirmed by using two spectroscopic techniques: MS and NMR. Hydroquinone, positional isomer of resorcinol, was used as cytotoxic positive control. Cytotoxicity was expressed as IC50 and was estimated in the range of 171–2142 µM for individual homologs depending on alkyl chain length. Alkylresorcinol-rich fraction, individual homologs, orcinol and olivetol exhibited cytotoxicity lower than hydroquinone but higher than resorcinol on normal cells. The highest cytotoxicity among isolated compounds was evaluated for C17:0. Structure–activity relationship was dose dependent and can be described by quadratic function. This study extends our knowledge about potential safety of use of alkylresorcinols in diet supplements, cosmetics or pharmaceutical products.