Therapeutic Intervention of Nutraceutical Eriomin Associated with Metformin to Improve the Control of Hyperglycemia in Patients with Prediabetes: a Double-blind, Randomized, Placebo-controlled Crossover Clinical Trial

Recent evidence shows that bioflavonoids from citrus fruits and herbs can reduce hyperglycemia, dyslipidemia, insulin resistance and the systemic inflammatory process related to type 2 diabetes (T2D). Although they can be found in fruits and herbs, bioflavonoid supplements and nutraceuticals can provide sufficient and safe amounts of bioactive compounds to prevent the development of metabolic disorders, such as metabolic syndrome, diabetes, obesity and others. Eriocitrin flavanone, present in lemons, limes and oranges, has demonstrated anti-inflammatory, anti-hyperglycemic and antioxidant properties and is an integral part of lemon bioflavonoid supplements that have been widely marketed.

Eriocitrin metabolism, similar to hesperidin, is resistant to pancreatic enzymes and are mostly deglycosylated by intestinal bacteria (Bacteroides distasonis or Bacteroides uniformis) to eriodictyol before absorption. A minimal amount can be absorbed as glycosylated in the upper intestine. Eriodictyol, the aglycon of eriocitrin, can be metabolized by intestinal bacteria (with 3,4-dihydroxycinnamic acid formation) to homoeriodictyol and hesperetin through methoxylation. In the liver, eriodictyol is metabolized into glucuronides and conjugated sulfates of eriodictyol, homoeriodictyol, and hesperitin, through sulfation, glucuronidation and methylation, and later released into the circulation to exert biological activity.

Eriocitrin can increase the total antioxidant capacity, leading to a decrease in inflammatory markers (IL-6, MCP-1 and us-CRP) in the blood and organs of mice supplemented with the flavonoid. Eriocitrin also increased catalase and glutathione enzymes in the liver of diabetic rats, and decreased lipid peroxidation in blood, liver and kidney. Furthermore, oral administration of eriodictyol to diabetic rats improved glucose metabolism in the blood, liver and kidney, and suppressed diabetes by upregulating PPARγ29 mRNA expression.

Based on this experimental evidence, the nutraceutical Eriomin, composed of lemon bioflavonoids, was tested as a dietary supplement to control mild to moderate hyperglycemia in pre-diabetic and diabetic patients. After three months of therapy, there was a decrease in hyperglycemia, improvement in insulin resistance and a decrease in HbA1c.

Thus, the hypothesis of the current study is to use the nutraceutical Eriomin as a co-adjuvant to oral biguanide (metformin) therapy, improving control of hyperglycemia and insulin resistance, while increasing efficacy with a low dosage (250 mg/d) of the nutraceutical. It is expected to improve the quality of the microbiota, the glucose metabolism and body composition, in addition to reducing the side effects associated with the continuous use of metformin.