Extraction of charantin from the fruits of momordica charantia using high pressure solvent

Abstract

Charantin is mixture two steroid compounds, which has been shown to possess antidiabetic activity. Charantin can be to found in fruits of Momordica charantia (bitter melon), prevalently grown in Thailand and other Asian countries. The compound is highly soluble in chloroform thus extraction of such compound was conventionally carried out in the solvent using a Soxhlet apparatus. This process is simple however, the product may be toxic if chloroform residue is left in the extract. In this study, a more benign alternative for charantin extraction accelerated solvent extraction (ASE) with ethyl alcohol was proposed. Experiments were conducted to determine the effects of several factors including type of solvent (water, ethanol, acetone, dichloromethane, and ethyl acetate), solvent composition, flow rate (2-6 ml/min), temperature (50-150 degree celius), while the pressure was maintained at 10 MPa. The quantitative analysis of charantin was performed withhigh performance liquid chromatography (HPLC). Prior to the analysis, however a purification step was required to remove chlorophylls and sugars that could interfere with the analysis. This was achieved by washing the crude extract with 50% methanol, followed by 70% methanol, and hexane, respectively. The results from this study reveal that the efficiency of accelerated solvent extraction depends on the type of solvent used. Acetone and ethanol gave higher efficiency than ethyl acetate, dichloromethane, and water. Extraction yield was also found to increase as temperature increased and similar yields could be achieved using either pure ethanol or a 50% ethanol solution in water. Compared with Soxhlet extraction, ASE was shown to permit high extraction efficiency as it requires low solvent volume and short extraction time.