On the relationship between the chemical structure and the cyclic AMP phosphodiesterase inhibitory activity of flavonoids as studied by 13C NMR - Sakamoto, Y; Ohmoto, T; Nikaido, T; Koike, K; Tomimori, T; Miyaichi, Y; Shirataki, Y; Monache, F D; Botta, B; Yokoe, I; Komatsu, M; Watanabe, S; Ando, I (B Chem Soc JPN, 1989)