Exosome-encapsulated herbal compounds increase the cellular toxicity of different cell lines. (A) Cytotoxicity MTT assays of the Exo-compounds (the concentrations of Exo, Exo-Bai, Exo-Hed, Exo-Nef, Exo-Rg3, Exo-Rapa or Exo-Rb1 were 4000 μg/mL, 1000 μg/mL, 200 μg/mL, 5 μg/mL, 2000 μg/mL, 5 μg/mL and 5000 μg/mL, respectively) and herbal compounds alone (the concentrations of Bai, Hed, Nef, Rg3, Rapa and Rb1 were 1000 μg/mL, 200 μg/mL, 50 μg/mL, 2000 μg/mL, 5 μg/mL, 5000 μg/mL, respectively) were performed on both the differentiated PC-12 cells and neuron-2a cells by the MTT method after 48 h of the compound treatments. (B) Flow cytometric measurements of the cytotoxicity of Exo-compounds (the concentrations of Exo-Bai, Exo-Hed, Exo-Nef, Exo-Rg3, Exo-Rapa or Exo-Rb1 were 150 μg/mL, 3 μg/mL, 0.6 μg/mL, 100 μg/mL, 200 ng/mL, 600 μg/mL, respectively) and herbal compounds alone (the concentrations of Exo, Bai, Hed, Nef, Rg3, Rapa or Rb1 were 150 μg/mL, 3 μg/mL, 0.6 μg/mL,100 μg/mL, 200 ng/mL, 600 μg/mL, respectively) were validated on differentiated PC-12 cells and (C) Neuron-2a cells by flow cytometry after 24 h of the compound treatment. (D) The intracellular concentration of Bai on differentiated PC-12 was determined by UHPLC-MS at 0.5 h, 1 h, 6 h, 12 h, 24 h and 48 h after treatment with 10 μg/mL of Exo-Bai or Bai alone. All of the experiments were performed as three independent experiments. One-way ANOVA was used to compare the data: * p < 0.05, ** p < 0.01, *** p < 0.001.