Abstract
Objectives: We have examined the relaxative response to the water extract of Rheum undulatuum (ERU) and water extract of alcohol processed Rheum unddatum (ARU) with isolated thoracic aorta from sprague dawley (SD) rat Methods: Rat thoracic aorta was investigated in vessel segments suspended for isometric tension recording by polygraph. Responses to ERU and ARU were investigated in vessels precontracted with 5- hydroxytryptamine(5-HT). Results: We found that the thoracic aorta segments responded to ERU and ARU with a dose-dependent vasorelaxation. 1. The thoracic aorta segments responded to ERU and ARU with a dose-dependent vasodilation. 2. The amounts of emodin were 0.063% and 0.076% in ERU and ARU, respectable. 3. The 5-HT induced contraction at $10^{-4}$ were inhibited by 85.2$\pm$4.76% and 83.4$\pm$8.82% after addition of the 0.lmg/mL. water extract of ERU and ARU. 4. The 5-HT induced contraction at $10^{-4}$% were inhibited by 100% after $10^{-4}$ emodin. Conclusion: In conclusion, vasodilation effect of the water extract of Rheum undulatum L. in rat thoracic aorta was not decreased according to the alcohol processing of Rheum undulatum L.