Abstract:

Aim: The purpose of this study is to indicate the anti-obesity and anti-diabetes mechanism of bitter melon
(BM) through an anti-inflammatory mechanism. Methods: Obese mouse models were induced by feeding high fat diet
(45% calories from fat; Research Diets no. D12451) for 12 weeks. Then the mice were divided into four groups according
to their diets (low fat diet, 10% calories from fat; Research Diets no. D12450B; low fat diet supplemented with 5% BM;
high fat diet; high fat diet supplemented with 5% BM): LFD, LFD + 5% BM, HFD and HFD + 5% BM, respectively. Six
weeks later, body weight gain, blood glucose, blood fat and other metabolic indices were investigated. Using qPCR, ELISA
and Western blotting, we also explored inflammatory cell infiltration, inflammatory cytokine expression and related signal
pathways. Results: After dietary supplementation of BM, body weight and blood fat of obese mice were dramatically
reduced almost to those in the LFD group. The expression of F4/80 and mMCP-6, characteristic genes of macrophage and
mast cell, and inflammation cytokines (MCP-1, IL-6 and TNF-α) in adipose tissue were decreased sharply. The metabolism
index of glucose and fat also returned to normal level, and glucose intake related signals (AKT, PPARγ and Glut-4)
were enhanced. This study not only explains how BM ameliorates diet-induced obesity and diabetes, but also supplies a
preliminary guideline for the development of anti-obesity and anti-diabetes functional foods with BM.

Key words: Momordica charantia, obesity, insulin resistance, inflammatory cells, inflammatory cytokine