GC-MS Determination of Bioactive Constituents of the Methanolic Fractions of Cnidoscolus aconitifolius

Abstract

Background: Diabetes mellitus is a major metabolic disorder affecting a huge population all over the world. Cnidoscolus species have been extensively used for the management of diabetes in folkloric medicine. The presence of diverse secondary metabolites has been reported from species of the genus Cnidoscolus. However, there has not been much information available on phytochemical components and biological activity in the leaf methanol extract of Cnidoscolus aconitifolius. Objective: This study was designed to extract and identify some bioactive compounds in the leaf methanol fractions of C. aconitifolius which may provide insight on its pharmacological properties and its use in traditional medicine. Place and Duration of Study: Department of Biochemistry, Michael Okpara University of Agriculture, Umudike and National Cereals Research Institute Zaria, Nigeria between June 2012 and July 2013. Methodology: Twenty grams of the powdered sample was subjected to column chromatography over silica gel (60-120 mesh) and eluted with 100 ml each of n-hexane, petroleum ether, chloroform, methanol and respectively at the rate of 1ml/min. The eluates were concentrated and labeled as FI, F2, F3 and F4. The percentage yields of the fractions were 7.55%, 6.00%, 15.5%, and 65.00% (w/w) respectively. n-hexane and petroleum ether did not elute much of the compounds. The active methanol fraction of C. aconitifolius extract (F4) which showed the highest hypoglycaemic effect as identified by Oral Glucose Tolerance Test (OGTT) in rats was taken for Gas Chromatography- Mass Spectrometry (GC-MS) analysis for separation of the bioactive components. GC-MS analysis was performed using a GC-MS (Model: QP2010 PLUS SHIMADZU, JAPAN) comprising a AOC-20i auto-sampler and gas-chromatograph interfaced to a mass spectrometer. Results: The bioactive organic components of the GC-MS analysis provided peaks of six different phytochemical compounds, with their retention time (RT) and peak area (PA) in addition to minor constituents. The major compounds are dodecanoic acid-1, 2, 3- propanetriyl ester ( RT:25.74, PA: 51.18%), cyclotetradecane (RT: 23.39, PA:15.59%), eicosanoic acid (RT:20.61, PA:18.47%); octadecanoic acid (RT: 16.82, PA:1.21%), 4-nitrosophenyl-beta-phenyl propionate (RT: 11.53, PA: 4.38%), benzene acetic acid, phenyl malonic acid and 3-oxo-4-phenylbutyronitrile (RT:10.34, PA: 9.17%). The presence of these compounds in the plant extract may at least be responsible for one of the pharmacological properties of C. aconitifolius and thus recommended as plant of phyto-pharmaceutical importance