065: Elucidating In-Vitro and In-Situ Anti-Diabetes and Anti-Inflammatory Potential of Black Rice Bioactives

Introduction

Diabetes mellitus is a chronic disease causing severe health concerns globally. Despite the multifactorial etiology of diabetes mellitus, chronic inflammation stands as a significant pathophysiological determinant in its development and progression. Black rice, a prominent anthocyanin-rich cereal, contains various physiologically active compounds. This study aims to demonstrate the antidiabetic and anti-inflammatory activities of black rice bran extracts, a food-derived material, to assist in pre-diabetic management while suggesting its potential as an alternative to diabetic medications.

Methods

Black rice bran extracts were obtained using various solvent extraction methods and were lyophilized to evaluate their antidiabetic potential through enzyme inhibition assays against α-glucosidase and dipeptidyl peptidase IV (DPPIV). In-situ DPPIV enzyme inhibitory activity was assessed using a human colorectal adenocarcinoma Caco-2 cell line. Additionally, anti-inflammatory activity was analyzed by measuring interleukin-6 (IL-6) production via enzyme-linked immunosorbent assay (ELISA) in the human monocytic THP-1 cell line treated with black rice bran extracts.

Results

The ethanol black rice extracts exhibited potent inhibition against α-glucosidase and DPPIV with half maximal inhibitory concentration (IC50) values of 0.02 mg/mL and 0.274 mg/mL, respectively. In the in-situ experiments, the methanol and ethanol black rice extracts exhibited the highest DPPIV inhibition of 45.24% and 43.33%, respectively, as compared to the control. The results were observed consistent with the in-vitro experiment. Additionally, black rice solvent extracts (methanol, ethanol, and acetone) using 0.2 mg/mL concentration exhibited more than 60% inhibition of IL-6 production as compared to the control.

Significance

As per our knowledge, there are no previous experimental studies on the validation of DPPIV inhibitory activity in black rice bran extract. DPPIV inhibition elicits its antidiabetic effects through glucose-dependent enhancement of glucagon-like peptide 1 (GLP-1) efficacy. The current results of the anti-diabetic effect through DPPIV inhibition mitigate concerns about common adverse effects of diabetic medications, such as weight gain and hypoglycemic shock. Furthermore, the study confirmed black rice’s multifaced antidiabetic activity through its effectiveness in α-glucosidase inhibition, which prevents blood glucose spikes by slowing complex carbohydrate breakdown, as well as its ability to suppress inflammation, a contributing factor to diabetes.

Authors: Gwanjo Lee, Subhash Kumar, Youngsook Oh, Eunchan Lee, Myunghee Kim