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Ethnobotanical Leaflets 11: 217-223. 2007. An Evaluation of the Genotoxic
Effects of Seed Decoction of Cassia tora L.
(Leguminosae) in Allium
cepa Model Pallavi Solanke1, Mahendra Singh1, Hemant
Singh Rathore1*, Anjali Sharma1,
Mukesh Makwana1 and Sharad
Shrivastava2 Cell Biology' and
Limnology2 Unit, School of Studies in Zoology and Biotechnology, *<corresponding author hrvuz
2000@yahoo.co.in> Issued ABSTRACT Cytological effects of Cassia tora seed decoction were evaluated in Allium cepa root
tip cells. Bulbs were grown in pure tap water (controls, Gr. I) and also in
six concentrations (0.15 mg/ml, 0.31 mg/ml, 0.62 mg/ml, 1.25 mg/ml, 2.5 mg/ml
and 5 mg/ml) of C.tora seed decoction in tap
water (experimental, Grs. II). Parameters of study
were 'mean root length' and morphology i.e. colour
and shape of root tips at 72 hr of cultivation and 'mitotic Index',
chromosomal aberrations and abnormal mitosis at 48 hr of cultivation. Physico-chemical characterization of decoction was also
made. No changes in the morphology of root tips occurred at any concentration
of C.tora seed decoction, however, change in
color did occur at all concentrations. Mitotic index and mean root length
remained unaffected at first two concentrations but all higher four
concentrations caused progressive mitodepression
hence a decline in root growth occurred. No abnormal mitosis and no
chromosomal aberration occurred at all at any concentration. Results suggest
that water soluble constituents of C.tora
seeds could only lower mitosis but not caused any adverse genotoxic
effects in mitotically dividing A.cepa
root cells under laboratory condition. Key words: Cassia tora, Allium cepa, emodin, mitosis INTRODUCTION Cassia tora Linn is well known oriental herb in traditional medicine1. Its seeds are used as coffee substitute, health drink and in curing several human ailments2-4. The seeds of C. tora contains a variety of bioactive anthraquinones including emodin, chrysophanol and rhein etc which are mainly responsible for pharmacological action ascribed to them5-8. Anthraquinones present in C. tora seeds have also been found to be mutagenic and cytotoxic too in prokaryotic and eukaryotic cells 9-14. Present study was planned to find out the genotoxic effect of C. tora seed extract in Allium cepa test which is an internationally accept model for such studies15. MATERIALS Allium cepa Dry healthy common onions (2n=16) 2.0 to 2.50 cm in diameter were obtained from the local market. Test herbal compound Dried seeds of medicinal plant Cassia tora locally called 'Punvad' were purchased from local herbal medicine shope. These seeds were authenticated by Botany department of this University. Seeds were crushed in electrical grinder to get coarse powder. Each time 5 gm of C. tora seed powder was boiled in 1000 ml of tap water for 5 minutes to prepare decoction of seeds. After cooling evaporated (lost) volume of decoction was made up to 1000 ml with tap water. Experimental Design Experiments were planned as per
international protocol(15) for Allium
cepa test. A set of twelve tubes were filled
with pure tap water (Group I, controls). Another series of 12 test tubes were
filled with each concentration of C.tora
seed decoction (Group II, experimental). All solutions were changed every 24
hours. After 48 hours two onions out of 12 in each series with most poorly
growing roots were removed. Same day i.e. after 48 hours of cultivation 02 mm
of 05 root's tips were cut off from five individual bulbs and were fixed in acetoalcohol (1:3 v/v acetic acid and absolute ethanol)
for 24 hours and were stored in 70% ethanol. Every time fixation was done at
a fixed time, Squashing of root tips and observation of slides Root tips were squashed in N-HCl and 2% acetocarmine (BDH) stain. Four fields from each slide were observed to cover about 50 cells in each i.e. total 200 cells per slide hence 3000-4000 cells were observed for each group of onions. Mitotic index was calculated as total number of dividing cells per 100 observed cells. Slides were also observed under oil immersion lens to find out mitotic arrest, aberrations, polyploidy etc. as detailed in Table5. Physico-chemical Analysis of
decoction All parameters were done as per standard methods described in APHA16. Statistics Experiments were repeated three times. Students 't' test was applied at 5% level of significance. RESULTS 1. Physicochemical properties of decoction of C. tora is shown in (Table1) It shows slight deviation from pure tap water due to presence of many water soluble constituents of C. tora seeds. Table 1: Physico-chemical properties of Cassia tora seed decoction.
2. Morphology: color and shape of root tips (Table 2) Among controls color of root tips was white and tips were straight and pointed in shape which is usual features of growing roots of Allium cepa bulbs. Bulbs grown in Cassia tora seed decoction at four initial concentrations (0.15 mg/ml to 1.25 mg/ml) revealed no chance in the shape of tips but they appeared pale yellow in color while at last two concentrations (2.5 mg/ml and 5 mg/ml) they appeared dark yellow, however, no changes in their morphology could be noticed. Table 2:
Morphology of Allium cepa
root tips following 72 hrs. cultivation in Cassia tora seed decoction. (n=75)
3. Mean Root
length (table 3) Cassia tora seed decoction at concentrations 0.15 mg/ml and 0.31 mg/ml could not affect root growth but at all higher concentrations from 0.62 mg/ml to 5 mg/ml caused significant progressive inhibition in root growth. Table 3: Mean
root length of Allium cepa
after 72 hours of cultivation in different concentration of Cassia tora seed decoction (Mean ±
Statistically significant
base on 't' test at 5% level of significances (p = 1.98) (n=100) a = control vs all experimental groups (1 vs
2, 3, 4, 5, 6 & 7), b =group 2 vs 3 , c = group
3 vs 4 , d =
group 4 vs 5, e =group 5 vs
6, f = group 6 vs 7 4. Mitotic
Index (Table 4) No significant change in the value of mitotic index could be found at 0.15 mg/ml and at 0.3 mg/ml concentrations of C. tora seed decoction, however, progressive significant decline in mitosis in root cells could be observed at all concentrations i.e. from 0.62 mg/ml onward up to 5 mg/ml. Table 4: Mitotic
Index of Allium cepa
root tip cells after 48 hours of cultivation in different concentrations of Cassia
tora seed decoction (Mean ±
Statistically significant based
on 't' test at 5% of significances (p = 1.96) (n=2000) a = control vs all experimental groups (1 vs
2, 3, 4, 5, 6 & 7), b =group 2 vs 3 , c = group
3 vs 4 , d =
group 4 vs 5, e =group 5 vs
6, f = group 6 vs 7 5. Abnormal mitosis
and chromosomal aberration (Table 5) The analysis of large number of metaphases and anaphases did not reveal any type of abnormal mitosis or aberrations in controls and in any experimental groups. Table 5:
Cytological effects in Allium cepa root tips cells after 48 hr. of cultivation in
different concentration of Cassia tora seed
decoction.
+ Present , - Absent DISCUSSION Results of the present study have shown that seeds of Cassia tora did contain water soluble constituents because decoction was of dark brown colour and tips of roots of onions grown in decoction were also coloured (Table 2). The dark brown colour of decoction might have been due to presence of a yellow pigment - torachrysone like substance.17 It can be safely argued that results of present experiments are only due to presence of water soluble constituents of C. tora seeds.
Careful perusal of results indicated that when Allium cepa bulbs were grown in C. tora seed decoction, only at higher concentrations mean root length and mitotic index declined, however, mitotic disturbances and chromosomal aberrations were totally absent. Mitodepression i.e. low mitosis hence low mean root length in root cells of A.cepa growing in the presence of C. tora seed decoction can be explained and understood on the basis of existing related reports.
The cytotoxicity of several medicinal and edible plants including seeds of Cassia tora were screened in K 562 human leukemia cells and found very very low i.e. only 4.6% inhibitory activity12. Bioactivity of Indian medicinal plants using brine shrimp (Artemia salina) lethality assay13. They tested alcoholic extracts of seeds of C. tora and found very poor LC50 value (725 mg/ml; 24 hr). Present results are in very good conformity with these two reports that only at higher concentrations of C. tora seed decoction only growth of onion root was inhibited hence low mean root length and low mitotic index could be recorded and no other adverse effect like disturbances in mitotic or any chromosomal aberrations could be seen.
It is suggested that because of quinone structure, emodin may interfere with electron transport process and in altering cellular redox status may account for its cytotoxic properties in different systems.14
In fact substances which can lower cell division without causing genotoxicity can be used as anticancer agents. Of late, molecular mechanism of emodin action was studied in mammalian cells and emodin a laxative component was found to be a future candidate as antitumor agent. According to authors, inhibitory effect of emodin on mammalian cell cycle modulation in specific oncogene overexpressed cells formed the basis of using this compound as anticancer agents. During apoptosis cells treated with cytotoxic agents are eliminated and emodin also induced apoptosis hence role of emodin in combination chemotherapy with standard drugs to reduce toxicity and to enhance efficacy is pursued vigrously. Its additional inhibitory effect on angionic and metastasis regulatory processes make emodin a sensible candidate as a specific blocker of tumor associated events14.
Recently re-evaluation of an old chinese remedy rhubarb (Rheum plamatuness or R. Officinalis) was made18 and it was concluded that emodin could be a promising candidate for the research and development of new anticancer drugs.
On the basis of present study it does not seem proper to argue either in favour or against controversial carcinogenic potential of anthraquinones laxatives, however, total absence of abnormal mitosis and chromosomal aberrations show lack of genotoxicity of water soluble constituents of C. tora seeds at least in Allium cepa model. ACKNOWLEDGEMENTS Authors thank Prof. Dr. D. Amritfale of S.S. in Botany for identifying C .tora. Departmental facilities are also acknowledged. REFERENCES 1. Anonymous. (1950) The Wealth of India, Raw Materials, Vol II PID-CSIR, New Delhi, pp. 98. 2. Koo, A., Chan, W.S., Li, K.M. (1976) Extraction of hypotensive principles from seeds of Cassia tora. Amer J. Chin Med 4(3): 245-248. 3.
Yen, G.C., Chung, D.Y., Wu,C.H. (2002) Free radicals in Foods: Chemistry,
nutrition and Health effects, In: Morello, M.J., Shahidi, F. HO, C.T. (Eds) 4.
5.
Duke, J.A. (1992) Hand book of phytochemical
constituents of GRAS herbs and other economic plants. Herbal reference
library. 6. Choi, J.S., Lee, H.J., Park, K.Y. etal. (1997) In-vitro antimutagenic effects of anthraquinone aglycones and naphthopyrone glycosides from Cassia tora. Planta medica 63:11-14. 7. Zhang, Q., Yin, J., Zhang, J. (1996) Comparison of contents of some active components between crude and processed seeds of Sickle Senna (Cassia tora) and their decoctions by HPLC. Chinese Herb 27:79-81. 8. Yen, G.C., Chen, H.W., Du, P.D. (1998). Extraction and identification of an antioxidative components from Jue Ming Zi (Cassia tora L.) Jour Agricult and Food Chem. 46:820-824. 9. Mian, M., Fratta, D., Rainaldi, G. etal. (1991): Superoxide anion production and toxicity in V-79 cells of six hydroxyanthraquinones. Anticancer. Res 11: 1071-1076. 10.
Muller, S.O., Eckert, 11.
12.
Masuda,
Toshiya., Oyama, Yasuo., Yamamoto., Natsuko. etal. (2003) Cytotoxic screening of medicinal
and edible plants in 13.
Krishnaraju, A.V., Tayi, V.N. Rao., Sundraraju, Dodda. etal. (2005)
Assessment of bioactivity of Indian medicinal plants using brine shrimp (Artemia salina)
lethality assay. Int. J. Appl. Sci.
14. Srinivas, Gopal., Suboj, Babykutty., Priya Prasanna, Sathiadevan etal (2007) Molecular mechanism of emodin action: Transition from laxative ingredient to an antitumor agent. Med. Res. Review 27(5): 591-608. 15.
Fiskesjo, Geirid (1995) Allium
test In-Methods in molecular Biology Vol. 43 In-vitro Testing
protocols. Edited by: S-O' Hare and C.K. Alterwill,
Humana Press Inc., 16.
APHA (1998) Standard methods for examination of water
and wastewater. 20th Edn. 17. Asolkar, L.V., Kakkar, K.K., Chare, O.J. (1992) Glossary of Indian Medicinal plants with active principle. Part I (A-K, 1965-1981) PID-CSIR New-Delhi pp. 180-181. 18. Huang, Qing., Guodong, Lu., Han, Ming Shen. etal. (2007) Anticancer properties of anthraquinones from Rhubarb. Medicinal Res. Reviews 27(5): 609-630. |
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