Triterpenoid from the Extract of Mangifera indica L . Roots Having Antispermogenic Activity KAUSHIK CHAKRABORTY

In vitro antispermogenic activity of an isolated triterpenoid from the extract of the root of the plant Mangifera indica L. was evaluated. The structure (3-O-acetyl-11,19-dinor-12,20-dimethylursane) was confirmed by the help of different spectral analysis.


INTRODUCTION
In continuation of our search on antispermogenic activity 1,2 and interest on Mangifera indica L. roots 1 , we are reporting a new pentacyclic triterpenoid having antispermigenic activity.
Different parts of the plant Mangifera indica L. are commonly used as folk medicine for a wide variety of remedies like treatment of bleeding hemorrhoids, jaundice, cough, asthma, bronchitis, Soxhlet apparatus (10 gm in 100 ml solvent system [Ether : Ethylacetate = 1:1]) with the aim of obtaining triterpenoid compounds.The total content of extracts was chromatographed in a glass made column (50 cm in length and 2 cm in diameter) using silica gel (60-120 mesh) as stationary phase and chloroform : methanol = 60:40 solvent system was used as mobile phase.
The structure of 3 rd fraction was elucidated by the help of IR, NMR & MS.The purity of the isolated compound was confirmed by LC-chromatogram in LCMS-Shimadzu 2010A spectrophotometer as compound showed single peak at 0.573 mAbs at 254 nm.
IR spectra (KBr) was recorded on a Jasco FTIR-5300 spectrophotometer.H 1 -NMR and C 13 -NMR recorded in Bruker AC-F 300 FTNMR and Mass in Shimadzu -2010A.The isolated antispermogenic compound with molecular weight 470 deduced from its LC-MS APCI positive mode mass spectrum by exhibiting a molecular ionic peak at m/z 471 for [M+H] + ion.
Compound (3 rd fraction) dissolved in DMSO (1 mg/ml) was mixed to sperm volume (1 ml) in the ratio of 1:10 and sperm count motility was assessed microscopically by following standard procedure. 1,2

RESULTS AND DISCUSSION
Total five fractions were collected separately after column chromatography, concentrated, dried under reduced pressure.The collected weight of fractions from first to last were 15, 13, 22, 10 and 12 mg respectively.Among those, the 3 rd fraction (22mg) showed promising antispermogenic activity, the 2 nd one (13 mg) showed negligible percentage decrease in sperm count motility (13% after 30 min) and other fractions did not show any antispermogenic activity.IR (max) KBr 2926 (C-H str of CH 3 -CO-), 2854 (C-H str), 1705 (-C=O str) cm -1 .In its H 1 -NMR spectrum (in DMSO D 6 + CDCl 3 Mix) it exhibited peaks for eight tertiary methyl groups at  0.57, 0.69, 0.71, 0.75, 0.80 and at 0.89 ppm.Further it exhibited peak at ´ 1.15 ppm for the H present in 6 membered alicyclic ring.A strong singlet at ´ 2.06 might be due to a methyl group attached to a carbonyl group.Peaks at  2.47, 2.48, 2.49 ppm recorded due to the -CH 2 and -CH of alicyclic ring adjacent to -OCO-R.A probable structure of the compound was developed as fig. 1 (3-O The C 13 -NMR data of the compound supported the structure of fig. 1  Further, mass spectra fragments confirmed the structure as in fig. 1.