We have performed the present piece of work to evaluate the effect of synthetic food coloring azo dye (sunset yellow) on actively dividing root tip cells of
The food colouring history dates back to early Egyptians and Romans civilization, when people used saffron, various flowers, carrots, mulberries, beets, and so forth to put colour to their foods [
Moreover these dyes have no nutritional value, they have no health benefits, they are not preservative [
As per norms of international research and the recommendations of the Codex Committee on Food Additives and Contaminants (CCFAC), intake of dye is under the control of ADI (acceptable daily intake) [
Sunset yellow (molecular weight 452.36) is an azo dye, is orange yellow in color, and is permitted food color in India. It is extensively used in almost every type of food preparation like sweets, jams and jellies, soft drinks, candies, ice cream, canned juice, sauces, pickles, and so forth. In the past few years, use of some food dyes including sunset yellow was banned in United States and Japan owing to its mutagenicity which has been evidenced from several mammals bioassays [
Unlimited use of azo dye could be hazardous in sense of its adverse effects on human and nonhuman biota. Despite its important role in our food, azo dye could be serious threat to human health. Some azo dyes are metabolized in the intestinal wall and liver, producing free aromatic amines that are potentially carcinogenic and mutagenic [
Plant bioassays are quite sensitive and simple technique in comparison to animal bioassay to assess the genotoxicity and cytotoxicity of a chemical compound [
In literature ample studies are available on mutagenicity and clastogenicity of sunset yellow on several test systems [
Inbred seeds of cultivar
For mitotic study homogenous and dry seeds were washed and then presoaked in distilled water for 5 hours. Presoaked seeds were placed in Petri plates layered with moistened Whatman filter paper and kept in incubator for germination at
Fixed root tips were hydrolysed in 1 N-HCl for 5 min at
Variations in the mean of MI and Ab. % were subjected to one-way analysis of variance (ANOVA) using post hoc multiple comparison from Tukey’s test (
Table
Occurrence of normal and disturbed phases of cell cycle in meristematic root tip cells of
Treatments | Normal metaphase | Normal anaphase | Normal telophase | Disturbed metaphase | Disturbed anaphase | Disturbed telophase | |
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Replicate 1 | Control (distilled water) |
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Replicate 2 |
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Replicate 3 |
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Replicate 1 | 1% dye |
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Replicate 2 |
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Replicate 3 |
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Replicate 1 | 3% dye |
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Replicate 2 |
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Replicate 3 |
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Replicate 1 | 5% dye |
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Replicate 2 |
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Replicate 3 |
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Frequency of mitotic abnormalities (at metaphase, anaphase, and telophase) in azo dye treated root tip meristems of
Treatments % | Metaphase abnormalities % | Anaphase abnormalities % | Telophase abnormality (%)*** | ||||||||
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Pm | Un | C-mt | St | Oth* | Bg | Lg | Fm | St | Oth** | ||
Control | — | — | — | — | — | — | — | — | — | — | — |
1 | — | 0.01 | — | 1.48 | 0.6 | 0.01 | — | 0.17 | 1.0 | — | 1.50 |
3 | 1.09 | 0.32 | 0.30 | 2.80 | 0.29 | — | 0.35 | 0.71 | 1.33 | 0.19 | 1.75 |
5 | 2.02 | 1.54 | 1.11 | 3.30 | 0.47 | 0.21 | 0.51 | 0.79 | 2.59 | 0.67 | 2.17 |
Pm: precocious movement of chromosomes, Un: unorientation, C-mt: C-mitosis, St: stickiness, Bg: bridge, Lg: laggards, Fm: forward movement of chromosomes, Oth: other abnormalities, *clumping, **fragmentation, unequal separation, and binuleate cells, and ***micronuclei.
Reciprocal relationship between MI (%) and total abnormalities (%) along with the increasing doses.
Dye treatments | Total cells observed | **T Ab. (%) | Mitotic index (MI) (%) |
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(mean ± SE) | (mean ± SE) | (mean ± SE) | |
Control | 1715 ± 9.64 | 00.00a* | 14.60 ± 0.19a* |
1% | 1700 ± 5.85 | 3.57 ± 1.10a | 12.32 ± 0.40a |
3% | 1748 ± 8.37 | 7.28 ± 0.20b | 7.88 ± 0.12b |
5% | 1663 ± 12.01 | 12.80 ± 0.39c | 3.47 ± 0.51c |
*Mean values designated by different lowercase letters differ significantly at the 0.05 level by Tukey test; **T Ab. indicate total abnormalities.
As a consequence of irregular mitosis, several aberrations were recorded, namely, precocious movement of chromosome, 3.11%, unorientation, 1.87%, C-mitosis, 1.41%, forward movement of chromosome, 1.67%, micronuclei formation at prophase and telophase, 5.42%, chromatin bridge, 0.22%, and stickiness of chromosomes, 7.58% at metaphase and 4.92% at anaphase. Among all the aberrations observed, stickiness was registered to be the highest followed by micronuclei formation. Moreover some other anomalies have also been recorded such as binucleate cell, unequal separation, and fragmentation.
Klasterska et al. [
In general, chromosomal aberrations are changes in chromosome structure resulting from a break or exchange of chromosomal material [
Phenomenon of C-mitosis was first reported by Levan [
Present findings suggest the genotoxic and cytotoxic activity of food colouring dye on the cell cycle of
The authors declare that they have no competing interests.
Immense appreciation is to NBPGR (IARI), New Delhi, for providing seeds of