Effects of Kaempferia parviflora Wall. Ex Baker on endothelial dysfunction in streptozotocin-induced diabetic rats

Aim of the studyThe aim of the present study was to investigate an ethanolic extract of Kaempferia parviflora (KPE) reduces oxidative stress and preserves endothelial function in aortae from diabetic rats.Materials and methodsDiabetes was induced in Sprague-Dawley rats by streptozotocin (STZ) treatment (55 mg/kg i.v.). Vascular reactivity and superoxide generation were assessed in aortic rings using standard organ bath techniques and lucigenin-enhanced chemiluminescence, respectively.ResultsEight weeks after STZ treatment blood glucose was elevated compared to citrate treated control rats and there was an increased aortic generation of superoxide anion. In aortic rings acetylcholine-induced relaxation was impaired whereas endothelium-independent relaxation to sodium nitroprusside was unaffected. When aortic rings were acutely exposed to KPE (1, 10 and 100 μg/ml) there was a significant reduction in the detection of superoxide anion and enhanced relaxation to acetylcholine. Two separate groups of rats (control and diabetic) were orally administered daily with KPE (100 mg/kg body weight) for 4 weeks. KPE treatment reduced superoxide generation and increased the nitrite levels in diabetic aortae, and enhanced acetylcholine-induced relaxation. In the presence of NG-nitro-l-arginine (l-NNA), the relaxation to acetylcholine in aortic rings of diabetic rats was only partially inhibited, but was totally abolished in aortic rings from the KPE-treated diabetic rats. Indomethacin did not affect relaxation to acetylcholine in aortic rings of any group.ConclusionsThese results suggest that KPE, acutely in vitro or after 4 weeks administration in vivo, reduces oxidant stress, increases NO bioavailability and preserves endothelium-dependent relaxation in aortae from diabetic rats.

Graphical abstractThe ethanolic extract of Kaempferia parviflora (KPE), acutely in vitro or after 4-week administration in vivo, preserves endothelium-dependent relaxation in aortae from diabetic rats.Download high-res image (57KB)Download full-size image