Purslane Extract and Glucose Homeostasis in Adults with Type 2 Diabetes: A Double-Blind, Placebo-Controlled Clinical Trial of Efficacy and Safety.

Purslane extract (PE) is derived from Portulaca oleracea L., a medicinal plant used in traditional medicine for its antidiabetic properties. This randomized, placebo-controlled clinical trial was designed to evaluate the efficacy and safety of PE in improving glucose control, blood pressure, and lipid profile in adults with type 2 diabetes mellitus (T2DM) treated with a single oral hypoglycemic agent at baseline. Subjects were randomized to treatment with three capsules of PE/day or a matched placebo. Change from baseline to the week 12 end-of-follow-up visit measures of glucose homeostasis, hemodynamics, and lipid profile was compared by treatment assignment. In addition, these measures were evaluated in a subgroup of "responders," defined as patients whose week 12 HbA1c was lower than baseline values, regardless of treatment assignment. This group was further assessed in subgroups of baseline oral hypoglycemic treatment. A total of 63 participants were treated with either PE (n = 31, 11 females, mean age 52.4 ± 7.9 years) or matched placebo (n = 32, 11 females, mean age 58.3 ± 10.8 years). In the total cohort, systolic blood pressure declined significantly more in the PE group than the placebo group: -7.5 ± 5.0 versus -0.01 ± 0.3 mmHg, P < .0001. In the responders' subgroup, HbA1c declined significantly more in the PE group than the placebo group: -0.8% ± 0.4% versus -0.6% ± 0.5%, P = .03. Few adverse events were reported. These were mild and did not differ by treatment assignment. PE appears to be a safe, adjunct treatment for T2DM, significantly reducing systolic blood pressure in the total cohort and HbA1c in the subgroup of responders.

Olive leaf extract as a hypoglycemic agent in both human diabetic subjects and in rats.

Olive tree (Olea europaea L.) leaves have been widely used in traditional remedies in European and Mediterranean countries as extracts, herbal teas, and powder. They contain several potentially bioactive compounds that may have hypoglycemic properties. To examine the efficacy of 500 mg oral olive leaf extract taken once daily in tablet form versus matching placebo in improving glucose homeostasis in adults with type 2 diabetes (T2DM). In this controlled clinical trial, 79 adults with T2DM were randomized to treatment with 500 mg olive leaf extract tablet taken orally once daily or matching placebo. The study duration was 14 weeks. Measures of glucose homeostasis including Hba1c and plasma insulin were measured and compared by treatment assignment. In a series of animal models, normal, streptozotocin (STZ) diabetic, and sand rats were used in the inverted sac model to determine the mechanism through which olive leaf extract affected starch digestion and absorption. In the randomized clinical trial, the subjects treated with olive leaf extract exhibited significantly lower HbA1c and fasting plasma insulin levels; however, postprandial plasma insulin levels did not differ significantly by treatment group. In the animal models, normal and STZ diabetic rats exhibited significantly reduced starch digestion and absorption after treatment with olive leaf extract compared with intestine without olive leaf treatment. Reduced digestion and absorption was observed in both the mucosal and serosal sides of the intestine. Though reduced, the decline in starch digestion and absorption did not reach statistical significance in the sand rats. Olive leaf extract is associated with improved glucose homeostasis in humans. Animal models indicate that this may be facilitated through the reduction of starch digestion and absorption. Olive leaf extract may represent an effective adjunct therapy that normalizes glucose homeostasis in individuals with diabetes.