Introduction & Objective : Considering the higher incidence of atherosclerosis and cardiovascular disorders in diabetes mellitus, this study was conducted to evaluate the effect of oral one-month administration of red pepper (Capsicum frutescens) on the contractile reactivity of isolated aorta in diabetic rats.

Materials & Methods : For this purpose, male Wistar rats(n=32) were randomly divided into control, pepper-treated control, diabetic, and pepper-treated diabetic groups. For induction of diabetes, streptozotcin (STZ) was intraperitoneally administered (60 mg/Kg). Pepper-treated groups received pepper mixed with standard pelleted food at a weight ratio of 1/15. After one month, contractile reactivity of aortic rings to KCl and noreadrenaline was determined using isolated tissue setup.

Results : Serum glucose level showed a significant increase in diabetic group at 2^nd and 4^th weeks (P<0.001), while this increase was less marked in pepper-treated diabetic group at the 2^nd week (P<0.05). In addition, the latter group showed a lower contraction to KCl (P<0.05) and noreadrenaline (P<0.05) as compared to diabetic group. Meanwhile, there was no significant difference between control and pepper-treated control groups regarding contractile reactivity.

Conclusion : It can be concluded that oral administration of pepper for one month could attenuate the contractile responsiveness of the vascular system and may prevent the development of hypertension in diabetic rats.