Figure 4.

Results for tests of cAMP-specific phosphodiesterase (PDE) activity after incubation with elderberry (EB1, EB2) (a), sour cherry (SC1, SC2, SC3) (b), black currant (BC1, BC2) (c), and red grape (RG1, RG2, RG3) (d) extracts. Positive control (PC) was caffeine (1.21 mM). Data are expressed as relative (rel.) PDE activity (in percentage of solvent control) as mean ± standard deviation of three or four independent experiments. The significance of differences between sample and solvent control (100%) was assessed using Student’s t-test. * p < 0.05; ** p < 0.01; *** p < 0.001.