Effect of Bitter Melon Aqueous Extract and Pomegranate Oil on Glucose Concentration and Lipid Profile in Blood of Rats – Preliminary Study

Abstract

Conjugated fatty acids is a term given to a group of polyunsaturated fatty acids with conjugated double bonds systems in their carbon chains. Conjugated linolenic acids (CLnA) are present in seeds of certain plants e.g. α-eleostearic acid (cis-9, trans-11, trans-13 C18:3) in bitter melon (Momordica charantia, Cucurbitaceae) or punicic acid (cis-9, trans-11, cis-13 C18:3) in pomegranate (Punica granatum, Punicaceae), where usually they are most prevalent among fatty acids. Bitter melon and pomegranate have been widely investigated as they are commonly consumed plants which also have been used in traditional medicine, mainly in Asia, for treatment of many diseases, such as diabetes and atherosclerosis.

The aim of this study was to evaluate the influence of a diet supplemented with an aqueous extract of bitter melon fruits and/or with pomegranate oil on health status and lipid profile of blood. Sprague-Dawley female rats were divided into four groups with different diet supplementation: pomegranate oil (G), aqueous extract of bitter melon (M), pomegranate oil and aqueous extract from bitter melon (M+G), and control group (C). During the experiment fasting glucose concentration and total cholesterol (TC), HDL, LDL, and triglyceride (TG) concentration were measured in blood collected intravitally from the tail vein.

The modifications introduced into the diets did not influence negatively overall health condition of the animals. Bitter melon fruits extract slightly decreased the fasting glucose concentration during the experiment but its action was not statistically significant (p>0.05). Pomegranate oil caused an increase of fasting glucose level in G group (p=0.03657) but in M+G group its influence was diminished by the opposite activity of bitter melon fruits extract (p>0.05). TC was the lowest in G group and it did not change during the time of experiment, which can suggest that the diet supplementation with pomegranate oil prevents the age-related increase in cholesterol level. TC in blood of G group was significantly lower than in other groups in 14th (p=0.01057) and 21st (p=0.01433) weeks respectively. Aqueous extract of bitter melon fruits slightly diminished age-related TG increase, whereas pomegranate oil strongly prevents this tendency, as the TG content in G group was significantly lower than TG content in C and M groups at 14th (p=0.00060) and 21st (p=0.00003) week respectively. Similar activity, although not so pronounced, was visible as far as the M+G group was concerned.