Effect of phenolic acids on functions of rat aorta, vas deferens and on metabolic changes in streptozotocin-induced diabetes

OBJECTIVES: This study aimed to investigate the effects of antioxidant treatment on streptozotocin (STZ)-induced diabetic metabolic and smooth muscle (SM) complications in rats. MATERIALS AND METHODS: Threeweeks after STZ injection (i.v.), vehicle, p-OH benzoic (p-OHBA), protocatechic (PA) and gallic acids (GA) were separately administered (10 mg/kg each, i.p.) to the rats everyday for 3 weeks. Metabolic functions were observedregularly. The rats in all groups were sacrificed andaorta and Vas deferens were dissected. Theresponses of isolated organs to agonists (acetylcholine and phenylephrine) were recorded. RESULTS: Protocatechic acid prevented increase in food consumption and feces output significantly. The responses of isolated organs to agonists increased in the STZ-diabetic rats. The test drugs either prevented, exacerbated or didnot affect the SMchanges in the STZ-diabetic rats. CONCLUSIONS: It was concluded that p-OHBA, PA and GA may cause effects independently of their antioxidant effect and/or of diabeticcomplications. They may exhibit pro-oxidant activities in the experimental conditions applied.