Novel bitter melon extracts highly yielded from supercritical extraction reduce the adiposity through the enhanced lipid metabolism in mice fed a high fat diet

• A supercritical CO2 extraction was first used to isolate BME.
• The resulting BME consisted of extraordinarily large quantity of CLnA and CLA.
• A comprehensive investigation was performed concerning BMSO's anti-obesity effect.
• BMSO's anti-obesity effect was regulated by increased lipid metabolism and lepin's roles.

Bitter melon (Momordica charantia) is a species of edible plant known for its medicinal value towards diabetes and obesity. Due to the various compositions of bitter melon extracts (BME), the comprehensive knowledge concerning their anti-obesity effects was insufficient. Here we first introduced supercritical extraction to BME's preparation, (supercritical extraction is a relatively advanced extraction method with a better efficiency and selectivity and expected to be extensively used in future applications) and the resultants were subjected to HPLC analysis, validating the presence of 42.60% of conjugated linolenic acid (CLnA, cis9, trans11, trans13-18:3) and 13.17% of conjugated linoleic acid (CLA, cis9, trans11-18:2). The BMSO (bitter melon seed oil) was then administered to the HFD mice, an obesity model established by feeding C57BL/6J mice a high fat diet. Consequently, due to the BMSO's supplementation, the HFD mice showed a significantly decreased body-weight, Lee's index, fat index and adipose size, whereas the liver weight stayed unchanged. Meanwhile, the serum FFA (free fatty acids) levels returned to normal at the dosage of 10 g/kg, and the elevated serum leptin levels were also recovered by BMSO's supplementation with moderate and high dose. These findings suggested that BMSO restored the balance between lipid intake and metabolism, which was probably mediated by leptin's variation. In summary, a detailed anti-obesity effect was described with regard to a potent CFA's (conjugated fatty acid) combination offered by BME. A potential mechanism underlying BME's beneficial effects was proposed, paving the way for the better use of BME's pharmaceutical function to serve the obesity's treatment.