Evaluation of Extracts Containing Anthocyanins for Their Ameliorative Effects in an Animal Model of Insulin Resistance and Type 2 Diabetes

Abstract

Background: Nutraceuticals are the products which are being used as food and medicines for the treatment of several chronic diseases. Nutraceuticals are gaining much attention due to their easy availability, safety with no unwanted adverse effect, cheap and for their multiple therapeutic actions. Herbal nutraceuticals are popular because of a wide variety of biological actions largely because of the contents present like alkaloids, glycosides, terpenoids, oils, tannins and several other phytochemicals. Anthocyanins are water soluble pigments found in plants as secondary metabolites and can be of great therapeutic interest for the management of metabolic disorders associated with insulin signaling associated resistance and Diabetes.

Aim & Objectives: To investigate the effect of nutraceuticals for the treatment/improvement of inflammation associated conditions developed due to high calorie containing fatty diet and developed obesity, insulin signaling abnormalities and Type 2 Diabetes.

Methods: Intraperitoneal macrophages (IPMACs) were isolated from mice. These IPMACs were pretreated with extracts of black rice (BR) and purple sweet potato (PSP) followed by Lipopolysaccharide, (LPS) challenge to evaluate its effect on release of TNF-α and IL-6. Further, the effect of pretreatment with BR and PSP was evaluated on release of LPS induced TNF-α and IL-6 release in C57 BL/6 mice. In a separate experiment, Diet induced obese (DIO) mice (fed 60% high fat diet) were treated orally with extracts of BR and PSP at 100 mg/kg doses for 30 days to evaluate their effect on metabolic parameters and insulin resistance.

Results & Discussion: Extracts of black rice and purple sweet potato significantly reduced potent inflammatory cytokines like IL-6 and TNF-α in dose dependent manner in LPS challenged macrophages. Treatment of DIO mice with these extracts lowered fed blood glucose levels supporting the hypothesis that reducing inflammation may help improve insulin resistance. Extracts of BR and PSP also attenuated peripheral insulin resistance, as seen from significant improvement in insulin and glucose tolerance tests performed after multiple days of treatment.

Conclusions: The observed results demonstrate and support our hypothesis that extracts of black rice and purple sweet potato containing large amounts of Anthocyanins maybe useful agents in improving inflammation associated insulin resistance and Type 2 Diabetes.