In this randomized, placebo-controlled, double-blind study, we evaluated the antihypertensive effects of enzymatic hydrolysate from Styela clava flesh tissue in patients with type 2 diabetes mellitus (T2DM) and hypertension.

S. clava flesh tissue hydrolysate (SFTH) (n = 34) and placebo (n = 22) were randomly allocated to the study subjects. Each subject ingested two test capsules (500 mg) containing powdered SFTH (SFTH group) or placebo capsules (placebo group) during four weeks.

In the SFTH group, systolic and diastolic blood pressure decreased significantly 4 weeks after ingestion by 9.9 mmHg ( P < 0.01) and 7.8 mmHg ( P < 0.01), respectively. In addition, the SFTH group exhibited a significant decrease in hemoglobin A_1c with a tendency toward improvement in homeostasis model assessment of insulin resistance, triglyceride, apolipoprotein B and plasma insulin levels after 4 weeks. No adverse effects were observed in other indexes, including biochemical and hematological parameters in both groups.

The results of our study suggested that SFTH exerts a regulatory, antihypertensive effect in patients with T2DM and hypertension.