Lipase inhibitory activity of Lagenaria siceraria fruit as a strategy to treat obesity

Abstract

Objective: To explore pancreatic lipase inhibitory activity under different extraction conditions in order to track the most potent extract.

Methods: The methanolic extract and its fractions in solvents of increasing polarity, ether, chloroform, ethyl acetate, n-butanol and water, were made through cold maceration. Extracts in ethanol, ethyl acetate, acetone and chloroform were similarly prepared. Aqueous extract was prepared through hot decoction method. A reported method was used to determine lipase inhibitory activity of extracts and fractions over wide ranges of concentrations.

Results: The extracts and fractions exhibited concentration dependent activity. The IC₅₀ (μg/mL) values of methanolic, ethanolic, chloroform, ethyl acetate, acetone, ethyl acetate (after washing with water) and aqueous decoction were 293.40, 266.47, 157.59, 182.12, 352.34, 257.00, and 190.00, respectively. The activity of chloroform, ethyl acetate and aqueous extracts were close to that of the drug orlistat (IC₅₀ 146 μg/mL). Out of the fractions of the methanolic extract, the chloroform fraction was most active (IC₅₀ 189.6 μg/mL). The order of inhibitory activity of the fractions was as follows: chloroform＞ether＞n-butanolic＞aqueous＞ethyl acetate. The GC/MS analysis of the most active chloroform faction showed the presence of hexadecanoic acid, methyl hexadecanoate, isopropyl palmitate, methyl 9,12-octadecadienate, and methyl 9,12,15-octadecatrienoate.

Conclusions: The study suggests that Lagenaria siceraria has potential to inhibit pancreatic lipase activity, suppressing lipid digestion and thereby diminishing entry of lipids into the body. Regular intake of aqueous decoction of the fruit may therefore be recommended for control of obesity. Fatty acids and their esters may play role as inhibitors of lipase.

Keywords: Bottle gourd; Lagenaria siceraria; Lipase inhibitory activity; Obesity.