Effect of dietary supplementation of ginger and turmeric rhizomes on angiotensin-1 converting enzyme (ACE) and arginase activities in L-NAME induced hypertensive rats

•Ginger rhizomes inhibit ACE activity under hypertensive state.•Ginger rhizomes inhibit arginase activity under hypertensive state.•Ginger rhizomes increase NO level under hypertensive state. Ginger and turmeric rhizomes are used in folk medicine for the treatment of hypertension but the mechanism remains unclear. This study evaluated the effects of ginger and turmeric rhizomes on angiotensin 1 converting enzyme (ACE) and arginase activities in hypertensive rats. The animals were divided into seven groups (n = 10): normotensive control rats; hypertensive rats; hypertensive rats treated with atenolol; normotensive diet group supplemented with turmeric rhizomes; hypertensive rats supplemented with turmeric rhizomes; normotensive diet group supplemented with ginger rhizomes; and hypertensive diet group supplemented with ginger rhizomes respectively. After 14 days of pre-treatment with ginger and turmeric rhizomes-supplemented diet, the animals were induced with hypertension by oral administration of Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME). The results revealed a significant increase in ACE and arginase activities in hypertensive rats when compared with the control. However, pre-treatment with both rhizomes respectively caused a significant decrease in ACE and arginase activities with a concomitant increase in nitric oxide (NO) level. These activities could further buttress their antihypertensive benefits in folk medicine.