Isolation and Structure Modification of Biologically Active Compound Nimbolide from Azadiracthta indica A. Juss. Var. siamensis Valeton

Abstract

Malaria is found throughout the tropical and sub-tropical regions of the world and causes more than 300 million acute illnesses and at least one million deaths annually. Moreover the increase of drug resistance of Plasmodium falciparum remains to be serious problems. In order to continue antimalarial activity evaluation, nimbolide was isolated from the leaves of Azadiracthta indica A. Juss. Var. siamensis Valeton and its structure was modified. Experimentally, the ground-dried leave was extracted with acetone. Acetone extract was washed with hot hexane and crystallized with methanol. Recrystallization with dichloromethane : hexane mixture (1:1) provided nimbolide with 0.204% yield. The pure nimbolide reacted with 10% methanolic-KOH at 0°C to yield a reaction product of 17.02%. Structures of nimbolide and final product were illustrated by spectroscopy methods, i.e., infrared spectrophotometry, ultraviolet-visible spectrophotometry, nuclear magnetic resonance spectrometry and gas chromatography-mass spectrometry. It can be concluded that the effectiveness and convenient methods for nimbolide isolation and structure modification were developed.