Figure 3.

Decaffeinated coffee and nicotine-free tobacco confer neuroprotection in both α-synuclein transgenic and parkin null mutant flies. A, The number of DA neurons in the PPL1 cluster of 20-d-old transgenic flies expressing the human α-synuclein protein after exposure to food containing the given concentrations of decaffeinated coffee or nicotine-free tobacco extract. B, The number of DA neurons in the PPL1 cluster of 20-d-old parkin null mutants after exposure to food containing the given concentration of decaffeinated coffee or nicotine-free tobacco extract. C, Representative images of DA neurons in the PPL1 cluster of 20-d-old flies after exposure to food containing the given concentration of decaffeinated coffee or nicotine-free tobacco extract. Statistical tests were performed using Student's t test (*p < 0.01%; **p < 0.001%). The genotypes were as follows: TH-α-Syn, TH–Gal4 UAS–α-synuclein/TH–Gal4 UAS–α-synuclein; Park^−/−, park²⁵/park²⁵.