Results of cell metabolic activity by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT test) of the endothelial cell line EA.h 926 cultured in the presence of peptides 1–5, panel (a)—cells incubated in the presence of peptides for 1 day, panel (b)—cells incubated in the presence of peptides for 7 days. Cytotoxicity tests were performed in five replicates. The presented results are average values. Statistical significance was assessed using one-way ANOVA analysis of variance. Values for which the value **p < 0.001, ** p < 0.01, *p < 0.05 were considered statistically significant (see Supplementary Materials, Figure S1). No statistical significance was observed for 7 days incubation.