Phytochemical, GC/MS Analyses and Cytotoxic Effects of Maerua pseudopetalosa (Gilg and Bened.) De Wolf Tuber Fractions

Tuber extracts were subjected to column chromatography technique. Eight fractions were obtained for
ethyl acetate and twelve for ethanol. The brine shrimp lethality assay was used for assessment of
toxicity. For the first time promising result was shown for ethanolic extract. The fractions F8, F9, F11
and F12 were represented high toxicity equal to 1.25, 7.98, 0.185, 0.041 μg/ml respectively. Also F7
and F10 showed toxic effects (89.9, 30.6 μg/ml) whereas F5 (LC50 807 μg/ml) was weakly toxic.
Ethyl acetate fractions showed moderate toxicity for F7 and F4 (299.7 and 375.4 μg/ml), while F2, F6
and F8 were weakly toxic. However F1 exhibited high toxic effect.
Ethanolic extract which is the highest bioactive extract was subjected to TLC analysis. Tests for
secondary metabolites proved the presence of tannins, sterols and alkaloids. Also detection of
triterpenes, sterols and flavonoid represented positive results.
The fractions F8, F9, F11 and F12 with high cytotoxic values were identified by gas chromatography/
mass spectrometry analysis. Thirty three compounds were detected; which were not recorded in any
previous work in the available literature. Fraction 8 and 9 were found to be cytotoxic due to the
presence of oleate and linoleate compounds; with more cytotoxicity in fraction 8 as a result of the
additional presence of decenoic acid. Also, fraction 12 was more cytotoxic than fraction 11 and this
was attributed to the presence of a proline derivative (Proline-N-methyl- butyl ester). This compound
might be considered as the cause of the high toxicity of the fraction; since free proline was used as an
inhibitor of breast cancer development. Surprisingly, M. pseudopetalosa tubers were used in the
folkloric medicine of the natives of the South Blue Nile State in Sudan for the treatment of breast
cancer growth without any knowledge of their chemical constituents.