Fig. 1

Measuring the molecular weight and toxicity of HEPS. a The molecular weight of HEPS was measured by HPLC. b 24 and (c) 48 h PC12 cell incubation with different concentrations of HEPS (25, 50, 100, 200 and 250 μg/mL, respectively). Cell viability was measured by an MTT assay with HEPS. RPMI-1640 complete medium containing 10 % horse serum and 5 % fetal bovine serum is indicated as N⁺. Serum-free RPMI-1640 medium is indicated as N⁻. All values are mean ± SD and used a one-way analysis of variance (ANOVA, n = 6). All columns were significantly different compared with N⁻ and are indicated as * (p < 0.05)