Sumac as a novel adjunctive treatment in hypertension: a randomized, double-blind, placebo-controlled clinical trial

Background: Sumac (Rhus coriaria L., Anacardiaceae) is a medicinal plant traditionally used for the treatment of cardiovascular disorders. This study was designed to evaluate the effects of Sumac fruits in hypertensive patients. Material and Methods: a randomized, double-blind, placebo-controlled clinical trial was conducted on 80 hypertensive patients who were receiving captopril (25 mg day(-1)). The patients were randomly divided into 2 groups: the first group received R. coriaria fruit capsules (500 mg twice a day) and captopril (25 mg once a day), and the second one received placebo capsules (500 mg starch twice a day) and captopril (25 mg once a day), for 8 weeks. Blood pressure (BP) and body weight index (BMI) in all patients were determined every week. Phytochemical analysis of R. coriaria fruits was performed by using HPLC-DAD/QTOF-MS for analysing its phenolic compounds. Results: data indicated that hypertension was decreased significantly in R. coriaria group compared to baseline and placebo groups after 8 weeks, but BMI did not demonstrate a marked change in comparison with baseline and placebo groups. Moreover, the most abundant phenolic compounds identified in R. coriaria fruits were luteolin, apigenin, and quercetin flavonoids. Discussion: this finding suggests that R. coriaria fruits could be used as an effective natural remedy for management of hypertension. Since flavonoids were the main chemical constituents of this plant, its antihypertensive activity could be attributed to such compounds.