Curcuma Longa: The Dye as a Potential Indicator in Titrimetric Analysis

Abstract

Curcuma longa is the botanical name of a ginger plant belonging to the family of zingiberaceae. It
contains a colourful condiment with a distinctive pungent flavour. The natural product (curcuma longa)
has a pH range of 8 to 9. The quantitative evaluation gave a percentage yield of 15.2. On Thin-layer
chromatographic analysis, the dye gave Rf(methanol) value as 0.83. The ultra-violet visible (UV) spectra of
the dye also showed absorption of 480nm corresponding to the region of dyes. Infra-red (IR) spectra of the
dye from methanol extract showed intense peaks at 3423.8, 2961.7, 1739.5 and 1380.9 corresponding to
O-H stretching of alcohol, C-H stretching of methyl and methylene groups, C=O of amides stretching and
C-H bending vibrations of methyl and methylene groups respectively. An extraction was conducted where
a colourful yellow dye was produced from powdery curcuma longa with methanol as solvent. The indicator
property of the extracted dye was investigated using methyl orange as a reference indicator. It was
observed that the titrimetric end-points obtained for the dye present in curcuma longa compared
reasonably with those of methyl orange. I strongly recommend that the dye from curcuma longa can be
used as alternative to methyl orange during titrimetric analysis.