Lac—I

2 Final Report on the Safety Assessment of Shellac

Cosmetic-grade Shellac is a mixture of hydroxyaliphatic and alicyclic acids and their polyesters. It is used in cosmetic formulations at concentrations up to 25%.

Shellac had an LD50 of greater than 5 g/kg in rats. Results of acute animal toxicity studies using cosmetic formulations containing up to 6% Shellac indicated no adverse effects upon oral (rats), dermal (rabbits), ocular (rabbits), and respiratory tract (rabbits) exposure. Chronic inhalation of a Shellac hair spray formulation by rabbits produced no observable toxicity. No treatment-related toxic or pathologic effects were observed when concentrations of Shellac up to 10,000 ppm were fed to rats in a subchronic study.

Ames' mutagenicity assays, with and without metabolic activation, were negative.

Clinical assessment of safety of cosmetic formulations containing up to 6% Shellac indicated no measurable irritation and absence of sensitization and photosensitization.

It is concluded that cosmetic-grade Shellac is safe for use in cosmetic formulations at concentrations up to 6%, the maximum concentration tested.

Sesquiterpene acids from Shellac and their bioactivities evaluation

Seven sesquiterpenes, including four α-cedrene types (Shellolic acid A-C, Laccishellolic acid), two R-curcumene types (Shellolic acid D-E) and Shellolic acid F were isolated from Shellac, of which six were unknown. Their structures were elucidated by HR-ESI-MS, UV, IR, 1D and 2D NMR methods. The absolute configurations were confirmed via the Mosher's method, circular dichroism (CD) and optical rotation analyses. A plausible biogenetic relationship for 1-6 is proposed. Cytotoxic and anti-bacterial activities of the isolates were evaluated. To the best of our knowledge, none compounds showed any cytotoxic activity, which is well consistent with that Shellac used as nontoxic material in pharmaceutical formulations and food additives. However, compound 1 exhibited inhibitory activity against Bacillus subtilis with the MIC value of 0.1 mg/mL.