Analysis of Flavonoids in Oncidium Taka Flowers at Various Stages of Development
Colour is an important factor in determining the aesthetic value, and hence the economic value of flowers. Thus there is active research and development in chemistry of colour pigments especially in flowers and in the breeding of cultivars for preferred colors. Understanding the chemistry of colo...
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Format: | Thesis |
Language: | English English |
Published: |
2006
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Subjects: | |
Online Access: | http://psasir.upm.edu.my/id/eprint/5995/1/FBSB_2006_24.pdf |
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Summary: | Colour is an important factor in determining the aesthetic value, and hence the
economic value of flowers. Thus there is active research and development in
chemistry of colour pigments especially in flowers and in the breeding of cultivars for
preferred colors. Understanding the chemistry of colour pigments, especially the
changes in their composition and concentration as the flower develops, is essential as
a background for any attempt at genetic manipulation of flower colour. It is
important to know which pigments are normally present so that specific steps in their
synthesis can be targeted.
In this study the concentration of flavonoids in the flower of the orchid Oncidium
Taka, as it develops fiom the bud stage to the mature flower, was determined. Four
stages of flower development were arbitrarily selected, viz. the bud stage, partially
open flower, fully opened flower and the mature flower. The flavonoids were
extracted using methanol and the extract concentrated to dryness. The separation step
was by TLC followed by analysis using HPLC and UV Vis spectrophotometer. The
standard compounds for flavonoids were kaempferol, luteolin, naringenin and
myricetin.
The HPLC analysis result showed that kaempferol, luteolin and myricetin were
detected in at the level of 14.54 * 3.86, 1.80 0.27 and 3.04 * 1.51 pglg FW
respectively at the bud stage. Throughout the experiment, kaempferol concentration
decreased as the flower developed to maturity (0.12 0.03 pg/g FW). The same trend
was also observed for myricetin (0.24 * 0.1 1 pglg FW) at the third stage but
increased at the fourth stage. Luteolin on the other hand remained consistent at
approximately 1.35 * 0.44 pg/g FW throughout the development of the flower fiom
the bud to the mature stage. Naringenin could not be detected using HPLC at all
stages of flower development.
The qualitative analysis using TLC and W Vis spectrophotometer also indicated the
presence of kaempferol, luteolin and myricetin in Oncidium Taka petals extract.
Naringenin was only detected using TLC technique with solvent A (chloroform:acetic
acid:water (90:45:6 vlvlv)) and solvent C (chloroform:methanol(100:20 vlv)). All the
TLC plates were fumed with iodine vapour. |
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