ANTI-NUTRITIONAL CONSTITUENT OF COLOCASIA ESCULENTA ...

82.2.3.2
82.2.3.2.1
B2.2.3.2.2
Air-dried and powdered Amadumbe tubers were extracted with 95 per cent ethanol. The
ethanolic extract was successively partitioned with chloroform and n-butanol
respectively. The n-butanol-saponin fraction was then analysed by TLC. TLC procedure
was optimized using the eluents chlomform:methanol:water in varying ratios. It was
observed that there were many compounds present in the fraction. although at different Rt
values. The fraction obtained when the mobile phase composition of
chlomform:methanol:water was 65:5:10 and 85:10:5 gave the best TLC separation. The
TLC plates were evaluated and the Rf values determined. Only one of the compounds
was reproducible by comparison with the standard Rt values of 0.64. Similar fractions
from the TLC plates were combined by scraping off and were analysed by spectroscopic
methods for identification.
Chromatographic methods
Thin-layer chromatography
TLC was performed on Silica gel 60 F254 aluminium baked sheets of 20 cm by 20 cm
(Merck). Detection was undertaken. using iodine crystals and anisaldehyde/sulphuric
acid! acetic acid (90:5:S v/v).
Column chromatography
The n-butanol fraction was subjected to column chromatography, using Silica gel 70-240
mesh. Chloroform (CHCh) was initially used as the eluting solvent. Polarity of the
solvent was increased by adding methanol until a ratio of 50:50 was reached. Fractions
were pooled according to TLC analysis.
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