Increase on the coronary flow induced by dioclein in isolated rat heart

In the present work the effect of dioclein, a new flavonoid from Dioclea grandiflora, was investigated in rat hearts. The experiments were performed using the classic method of Langendorff, where flow, inotropic, chronotropic and electric parameters were analyzed. Bolus administration of Dioclein (1-100 mug) induced a sustained and dose-dependent increase in coronary flow with no modification in inotropic, chronotropic and electrical parameters. The duration of increase in coronary flow induced by dioclein (10 mug) was approximately 4-fold higher than that observed in the presence of sodium nitroprusside (NPS; 10 mug). Besides, the effect of dioclein measured as the area-under-the-curve was approximately 4.5-folds higher than that observed with NPS. Pre-treatment with L-NAME (100 muM) and indomethacin (10 muM) alone did not modify the effect of dioclein (10 mug), suggesting that nitric oxide (NO) and cyclooxygenase-derived factors were not involved. However, association of L-NAME plus indomethacin inhibited the duration of the effect of dioclein (10 mug) without changing its increase in the coronary flow. Furthermore, the absence of alteration in inotropism and chronotropism of the heart associated with its coronary effect suggest that dioclein could be an interesting lead compound for the development of drugs for the treatment coronary heart diseases. (C) 2002 Elsevier Science Inc. All rights reserved.