Bitter Melon Seed Oil-Attenuated Body Fat Accumulation in Diet-Induced Obese Mice Is Associated with cAMP-Dependent Protein Kinase Activation and Cell Death in White Adipose Tissue

Abstract

The aim of this study was to investigate the antiadiposity effect of bitter melon seed oil (BMSO), which is rich in the cis-9, trans-11, trans-13 isomer of conjugated linolenic acid. In Expt. 1, C57BL/6J mice were fed a butter-based, high-fat diet [HB; 29% butter + 1% soybean oil (SBO)] for 10 wk to induce obesity. They then continued to receive that diet or were switched to an SBO-based, high-fat diet alone (HS; 30% SBO) or containing bitter melon seed oil (BMSO) (HBM; 15% SBO + 15% BMSO) for 5 wk. The body fat percentage was significantly lower in mice fed the HBM diet (21%), but not the HS diet, compared with mice fed the HB diet. In Expt. 2, mice were fed an SBO-based, high-fat diet containing 0 (HS), 5 (LBM), 10 (MBM), or 15% (HBM) BMSO for 10 wk. In the LBM, MBM, and HBM groups, the body fat percentage was significantly lower by 32, 35, and 65%, respectively, compared with the HS control. The reduction in the HBM group was significantly greater than that in the LBM or MBM group. BMSO administration increased phosphorylation of acetyl-CoA carboxylase, cAMP-activated protein kinase (PKA), and signal transducer and activator of transcription 3 in the white adipose tissue (WAT), suggesting that PKA and leptin signaling might be involved in the BMSO-mediated reduction in lipogenesis and increase in thermogenesis and lipolysis. However, compared with the HS control, the HBM group had a significantly higher TNFα concentration in the WAT accompanied by TUNEL-positive nuclei. We conclude that BMSO is effective in attenuating body fat accumulation through mechanisms associated with PKA activation and programmed cell death in the WAT, but safety concerns need to be carefully addressed.

Phenolics and polyphenolics in foods, beverages and spices: Antioxidant activity and health effects – A review

“…Sathishsekar and Subramanian (2005) found that in vivo antioxidant efficacy of bitter melon extracts has highlighted the increased activity of naturally occurring hepatic antioxidant enzymes. Bitter melon possesses antioxidant, anti-tumour, anti-bacterial, anti-inflammatory, anti-viral, anti-obesity, anti-hypertension as well as antihyperglycaemic effects (Ahmad et al, 2012;Chen et al, 2012;Hsu, Fang, Liu, & Chen, 2013;. More recently, Chang et al (2015) found that the triterpenes 3β,25-dihydroxy-7β-methoxycucurbita-5,23(E)-diene and 3β,7β,25-trihydroxycucurbita-5,23(E)-dien-19-al isolated from bitter melon have insulin-sensitizing and insulin-substitution functions, which are correlated to their effects on inhibiting proteintyrosine phosphatase-1B (PTP-1B) and activating AMP-activated protein kinase (AMPK) inhibitor, respectively.…”

Roles of Peroxisome Proliferator-Activated Receptor α in Bitter Melon Seed Oil-Corrected Lipid Disorders and Conversion of α-Eleostearic Acid into Rumenic Acid in C57BL/6J Mice

“…Recently, we demonstrated that bitter melon seed oil (BMSO) is more potent than soybean oil, which has approximately the same amount of polyunsaturated fatty acid (PUFA), in attenuating high saturated fatty acid (SFA) diet-induced adiposity and hepatic steatosis in C57BL/6J mice [4,5]. BMSO is enriched in a fatty acid characterized by the presence of conjugated triene (i.e., cis -9, trans -11, trans -13 isomer of conjugated linolenic acid [6]), also termed α-eleostearic acid (α-ESA), which has potential as a functional lipid.…”

“…We previously reported that the anti-adiposity effect of BMSO is associated with cAMP-dependent protein kinase (PKA) activation and cell death in white adipose tissue (WAT) [4]. In mice subjected to a BMSO diet, their WAT had delipidative, inflammatory, browning, apoptosis, and autophagy characteristics (determined by histochemistry combined with proteomic approaches), indicating a dynamic repair/remodel process [14].…”

Phytochemical profile and biological activities of Momordica charantia L. (Cucurbitaceae): A review

“…Recent clinical trials have shown that plant extracts, including the São Caetano melon extract, have therapeutic potential against diabetes and metabolic dysfunction related to obesity in animals (Chen et al, 2012;Alam et al, 2015). The effects of this plant on mitochondrial function, during the accumulation of liver fat associated with obesity, were identified by .…”