Effect of Euphorbia hirta in Napthalene Induced Cataract in Rats

 

Rathnakumar K.1*, Jaikumar S.2 and Sengottuvelu S.3

1Department of Ophthalmology, Sri Lakshminarayana Institute of Medical Sciences, Pondicherry, India

2Department of Pharmacology, Sri Lakshminarayana Institute of Medical Sciences, Pondicherry, India

3Department of Pharmacology, Nandha College of Pharmacy and Research Institute, Erode- 638052

*Corresponding Author E-mail:- sengt@rediffmail.com

 

 

ABSTRACT:

Euphorbia is a genus of plants belonging to the family Euphorbiaceae. Euphorbia hirta is a very popular herb amongst practitioners of traditional herb medicine. The present study was undertaken to evaluate the effect of ethanolic extract of Euphorbia hirta aerial parts in naphthalene induced cataract in rats. Euphorbia hirta aerial extract at dose levels (200 and 400 mg/kg), and Vitamin E (50mg/kg) were used as standard drugs, while liquid paraffin was used for control. The test drugs were administered for 25 days. Naphthalene (0.5 g/kg for first 3 days and 1g/kg thereafter for a period of 25 days) was used to induce cataract. Ophthalmoscope was used to examine the percentage of cataract incidence and opacity index. Naphthalene produced a significant mature cataract and an increase in the opacity index at various stages. Euphorbia hirta  extract decrease the onset and maturation of cataract against naphthalene challenge in rats.  From the results it was concluded that the Euphorbia hirta aerial extract showed anti-cataract activity against naphthalene induced cataract in rats.

 

KEYWORDS :Euphorbia hirta, Cataract and Naphthalene


 

INTRODUCTION:

Euphorbia hirta, an important medicinal herb, belongs to genus Euphorbia, family Euphorbiaceae, which has been presumed for its favorable medicinal effects. Euphorbia hirta is a very popular herb amongst practitioners of traditional herb medicine, widely used as a decoction or infusion to treat various ailments gastrointestinal disorders (including intestinal parasites, diarrhoea, peptic ulcers, heartburn, vomiting, amoebic dysentery), asthma, bronchitis, hay fever, laryngeal spasms, emphysema, coughs, colds, kidney stones, menstrual problems, sterility and venereal diseases. The latex is applied on the lower eye lid like eye black to cure eye sore1.

 

Moreover, the plant is also used to treat affections of the skin. The following gastroprotective potentials were isolated from the Euphorbia hirta Two flavonoids have been isolated from Euphorbia hirta, namely quercitrin and myricitrin2,3. Sterols were isolated from Euphorbia hirta and chemically characterized as cycloarternol, 24- methylene-cycloarternol, α-sitosterol, euphorbol hexacozonate, 1-hexacosanol, tinyaloxin, campesterol and stigmasterol4,5.

 

Euphorbia hirta presents three hydrolysable tannins, namely, dimeric hydrolysable tannin, euphorbin E and the dimeric dehydroellagitannins, euphorbin A and euphorbin B6. The triterpenes α -amyrin, taraxerone (EH-1), taxerol as well as α -amyrin acetate have been identified from Euphorbia hirta7,8.

 

Scientific evidence is available for most of the above mentioned ethnobotanical uses except cataract.  The present study is, thus, aimed to study the effect of Euphorbia hirta against naphthalene induced cataract in rats.

 

MATERIALS AND METHODS:

Plant Material:

Aerial parts of Euphorbia hirta were collected from outskirts of Erode, Tamilnadu. Authentication has been done by Prof. V. S. Kumar, Scientists (F) and Head of the Office, Tamilnadu Agriculture University, Coimbatore (Tamilnadu). The voucher specimen (No.: BSI/ SRC/ 7/ 47/ 11- 12/ Tech. 221) has been deposited in the herbarium for future references.

 

Preparation of Extract:

The aerial parts of Euphorbia hirta were washed with fresh water to remove adhering dirt and foreign particles. The plant was shade dried, crushed and grinded to get coarse powder. The coarse powder was then placed with 90% ethanolic solution in a round bottomed flask. 500g of the coarse powder of the leaves of Euphorbia hirta in 1.0 liter of 90% ethanolic solution were macerated for 7 days. The mensturm was collected, concentrated by vacuum distillation and then air dried in an evaporating dish till constant weight was obtained.

 

Animals:

Wistar albino rats of either sex weighing 150-200gm were used for this study. The animals were placed randomly and allocated to treatment groups in polypropylene cages with paddy husk as bedding. Animals were housed at a temperature of 24±2oC and relative humidity of 30-70%. A12:12 light: day cycle was followed. All the animals were allowed to free access to water and fed with standard commercial pelleted chaw (M/s. Hindustan Lever Ltd., Mumbai). All the experimental procedures and protocols used in this study were reviewed by (IAEC) Institutional Animal Ethics Committee (932/a/06/CPCSEA) of Sri Lakshminarayana Institute of Medical Sciences, Pondicherry and were in accordance with the guidelines of the IAEC.

 

Pharmacological Evaluation:

Dose Schedule:

The animals were divided into four groups each consisting of six rats. Group 1 represented Control group of animals received suspension of 0.1% CMC solution. Group 2 received Omeprazole (10 mg/kg).  Groups 3 and 4, received Euphorbia hirta extract, in doses of 200and 400 mg/kg respectively. All the test drugs were administered orally by suspending in 0.1% CMC solution.

 

Experimental protocol:

Experimental model of cataractogenesis was induced in rats by feeding naphthalene (Umamaheswari et al., 2011) at a dose of 0.5 g/kg orally for the first 3 days followed by 1g/kg thereafter for a period of 25 days. Animals were divided into 5 groups consisting of six animals each. Group I received liquid paraffin (5 ml/kg b.w. orally) and served as the solvent control. Group II received naphthalene (0.5 g/kg b.w., orally for first 3 days and 1g/kg thereafter for 25 days) and served as the cataract control. Group III received the standard drug vitamin E at a dose of 50 mg/kg b.w., orally along with naphthalene and served as the positive control. Groups IV and V received the Euphorbia hirta aerial extract orally at a dose of 200 and 400 mg/kg b.w. respectively simultaneously with naphthalene. All the test drugs were administered for a period of 28 days.

 

Examination of the eyes:

The eyes of the rats were examined using an ophthalmoscope for morphological changes in the lens. Examination was performed after dilatation of the pupil with 1% tropicamide solution. Cataract formation was scored according to different stages. Stage 1: Clear normal lens, Stage 2: Peripheral vesicles, Stage 3: Peripheral vesicles with cortical opacities, Stage 4: Diffuse central opacities, Stage 5: Opacity involving the entire lens (Mature cataract). Cataract formation was considered complete (stage 5) when the red fundus reflex was no longer visible through any part of the lens and the lens appeared dull white to the naked eye. Percentage incidence of cataract was calculated using the following formula9

 

% Incidence = No of animals in each stage  x 100

                              Total no. of animals

 

Opacity index was calculated using the following formula10

 

Opacity Index = No. of eyes in each stage x Stage of the eye  

                                            Total no. of eyes

 

Statistical Analysis:

The values were expressed as mean ± SEM. The statistical analysis was carried out by one way analysis of variance (ANOVA) followed by Dunnet’s ‘t’ – test. P values <0.05 were considered significant.

 

RESULTS:

The effect of Euphorbia hirta aerial extract on naphthalene induced cataractogenesis in rats was studied and the percentage incidences of cataract and opacity index were observed. Effect of Euphorbia hirta leaf extract on % incidence of cataract on 28th day in naphthalene induced cataract rats were showed in table. 1.

 


 

Table 1. Effect of Euphorbia hirta leaf extract on % incidence of cataract on 28th day in naphthalene induced cataract rats

Drug Treatment

% Incidence of Cataract

Stage 1

Stage 2

Stage 3

Stage 4

Stage 5

Normal Control

Liquid Paraffin (10ml/kg)

100±1.87

0

0

0

0

Cataract Control

Naphthalene (1gm/kg)

0

0

0

72.54±2.65

45.66±1.76

Vitamine E (50mg/kg)

18.19±0.66

60.23±2.77

35.32±1.44

0

0

Euphorbia hirta Extract

(200mg/kg)

0

53.00±1.23

17.13±0.78

46.17±1.34**

0

Euphorbia hirta Extract

(400mg/kg)

0

53.00±2.25

26.16±1.74

19.19±0.86***

0

Values are presented as mean ± SEM (n = 6)

*P<0.05, **P<0.01 and ***P<0.001 Vs control


 

 


 

 

Table 2. Effect of Euphorbia hirta leaf extract on opacity index in naphthalene induced cataract rats

Drug Treatment

 

Opacity Index

4th day

7th day

14th day

21st day

28th day

Normal Control

Liquid Paraffin (10ml/kg)

0

0

0

0

0

Cataract Control

Naphthalene (1gm/kg)

0.45±0.02

0.62±0.01

2.47±0.01

3.55±0.03

4.98±0.02

Vitamine E (50mg/kg)

0

0

0.18±0.01**

0.72±0.02**

1.55±0.02***

Euphorbia hirta Extract

(200mg/kg)

0

0

2.14±0.01

2.67±0.02*

1.87±0.02***

Euphorbia hirta Extract

(400mg/kg)

0

0

1.45±0.01*

1.32±0.02**

1.43±0.01***

Values are presented as mean ± SEM (n = 6)

*P<0.05, **P<0.01 and ***P<0.001 Vs control

 

 


Ophthalmic examinations of the normal control lenses in the eyes l were in stage 1 throughout the duration of experimental period. The animals treated with naphthalene showed varying degree of cataractogenic changes as indicated by about 72.54% in stage 4 and 45.66% in stage 5 on the 28th day of drug treatment. At the end of drug treatment, the animals treated with the extract at a dose of 200 mg/kg b.w. showed 53.00% of animals in stage 2, 17.13% in stage 3 and 46.17% in stage 4 cataract, whereas the group treated with the extract at a dose of 400 mg/kg b.w. showed 53.00% of animals in stage 2, 26.16% in stage 3 and 19.19% in stage 4 cataract. Vitamin E the standard drug showed 18.19% of animals in stage 1, 60.23% in stage 2 and 35.32% in stage 3. None of the animals treated with the Euphorbia hirta leaf extract and the standard drug vitamin E showed stage 5 mature cataract at the end of the experiment.

 

Effect of Euphorbia hirta leaf extract on opacity index in naphthalene induced cataract rats were showed in table 2. Treatment with naphthalene showed an increase in the opacity index from 0.45 on the 4th day, 0.62 on the 7th day, 2.47 on the 14th day, and 3.55 on the 21st day followed by complete opacification (opacity index 4.98) on the 28th day. The groups treated with the Euphorbia hirta leaf extracts at a dose of 200 and 400 mg/kg b.w. showed a decrease in opacity index (1.87 and 1.43 respectively) when compared to naphthalene control. There was a marked reduction in opacity index (1.55) of the vitamin E treated group when compared to the naphthalene control.

 

DISCUSSION:

Cataract is a visual impairment occurs due to the opacification of crystalline lens. It affects around 17 billion peoples worldwide, although incidence of cataracts is increasing day by day among the elderly persons. Still today except surgery no other effective treatments have been successfully developed for cataract11.  From a public health perspective, it is important to identify the risk factors that affect the development and progression of cataract. Euphorbia hirta possess significant amount of flavonoids, which is a potent antioxidant have been studies against naphthalene induced cataract in rats. The cataract induced by naphthalene treatment in rats were confirmed by  varying degree of cataractogenic changes and an increase in opacity index with complete opacification at the end of the 4th week. The free radical involvements in the generation of cataract have been evidenced12. The antioxidant and free radical scavenging activities of Euphorbia hirta had already reported13.The anti cataract activity possessed by Euphorbia hirta leaf extract may be due to the presence of flavonoids the well known free radical scavengers.

 

CONCLUSION:

It can be concluded that the aerial parts of Euphorbia hirta exhibited anticatract activity against naphthalene induced cataract in rats. The results obtained from the study showed that Euphorbia hirta reversed the cataract induced by naphthalene in rats. To our knowledge this is the first report about in vivo activity of Euphorbia hirta in eye disorder and seems to raise some concern about the traditional indication of this species. Further studies required to prove its actual mechanism of action.

 

REFERENCES:

1.          Mei Fen Shih and Jong Yuh Cherng. Potential Applications of Euphorbia hirta in Pharmacology, Drug Discovery Research in Pharmacognosy, Prof. Omboon Vallisuta (Ed.), InTech Europe,  University Campus, Croatia. 2012.

2.          Johnson PB, Abdurahman  EM,  Tiam EA,  Abdu-Aguye I and Hussaini IM. Euphorbia hirta leaf extracts increase urine output and electrolytes in rats. Journal of Ethnopharmacology. 65; 1999: 63–69.

3.          Chen L. Polyphenols from leaves of Euphorbia hirta L. Zhongguo Zhong Yao Za Zhi. 16(1); 1991:  38–39.

4.          Atallah AM and Nicholas HJ. Triterpenoids and steroids of Euphorbia pilulifera. Phytochemistry. 2; 1972: 1860–1868.

5.          Galvez J, Zarzuelo A, Crespo ME, Lorente MD, Ocete MA and Jiménez J.  Antidiarrhoeic activity of Euphorbia hirta extract and isolation of an active flavonoid constituent. Planta Medica. 59(4); 1993: 333-336.

6.          Yoshida T, Namba O, Chen L and Okuda T.  Euphorbin E: A Hydrolysable tannin dimer of highly oxidized structure from Euphorbia hirta. Chemical and Pharmaceutical Bulletin. 38; 1990: 1113–1115.

7.          Pinn G.  Herbal therapy in respiratory diseases. Australian Family Physician. 30 (8);  2001: 775–779.

8.          Mukherjee KS, Mukhopadhyay B, Mondal S, Gorai D and Brahmachari G. Triterpenoid Constituents of Borreria articularis. Journal of the Chinese Chemical Society. 51(1); 2004:  229-231.

9.          Vats V, Yadav SP, Biswas NR and Grover JK. Anticataract activity of Pterocarpus marsupium bark and Trigonella foenum-graecum seeds extract in alloxan diabetic rats. Journal of Ethnopharmacology. 93; 2004: 289-294.

10.       Fukushi S, Merola LO and Kinoshita JH. Altering the course of cataracts in diabetic rats. Investigations of Ophthamology and Visible Science. 19; 1980:  313-315.

11.       Piyush Patel, Nurudin Jivani, Shailesh Malaviya, Tushar Gohil and Yagnik Bhalodia. Cataract: A major secondary diabetic complication. International Current Pharmaceutical Journal. 1; 2012: 180-185.

12.       Kothadia AD, Shenoy AM, Shabaraya AR, Rajan MS, Viradia UM and Patel NH. Evaluation of cataract prevention action of phycocyanin. International Journal of Pharmaceutical Sciences and Drug Research. 3; 2011: 42-44.

13.       Sharma NK and Prasad R. Oxidative injury to protein and their protection by phenolic acid antioxidants from Euphorbia hirta leaves Abstracts. Journal of Biotechnology. 136; 2008: 717-742.

 

 

 

Received on 15.05.2013       Modified on 05.06.2013

Accepted on 09.06.2013      © RJPT All right reserved

Research J. Pharm. and Tech. 6(8): August 2013; Page 908-911