Biokemistri Nigerian Society for Experimental Biology ISSN: 0795-8080 Vol. 20, Num. 1, 2008, pp. 33-37

Biokemistri, Vol. 20, No. 1, June, 2008, pp. 33-37

Effects of aqueous extract of Ocimum gratissimum on haematological parameters of Wistar rats

Olusegun Rabiu Jimoh^1*, Josiah Olaore¹, Luqman Aribidesi Olayaki², Ayokunle Olawepo¹ and Sikiru Abayomi Biliaminu³

Departments of ¹Anatomy and ²Physiology, College of Health Sciences, University of Ilorin, Nigeria
³Department of Chemical Pathology, University of Ilorin Teaching Hospital, Ilorin, Nigeria
*To whom correspondence should be addressed.  E-mail:rabiujimoh@ymail.com   Tel:+234-8033574898

Received April 29 2008

Code Number: bk08006

Abstract

The effect of aqueous extract of Ocimum gratissimum on hematological parameters of Wister rats was studied. Twenty five rats with weight ranging between 100-160g were used. The rats were divided into five groups; with group one as the control group. Increasing doses (0.2, 0.4, 0.8, 1.6g kg^-1 body weight) of the extract were administered orally to the other four groups for a period of four weeks. Significant (P< 0.05) decreases in the level of hemoglobin (Hb), packed cell volume (PCV), red blood cells (RBC), white blood cells (WBC) and other hematological parameters were observed.

Keywords:Ocimum gratissimum, haematologic effects, Wistar rats

INTRODUCTION

Nature has provided a very beautiful environment for us to live and survive. Man through the ages has depended on his immediate environment for solving his numerous problems. Man has learnt to depend on plants in order to provide solutions to the myriad of health problem plaguing him.¹             

The plant being investigated is popularly called African basil. It is a shrub commonly found in gardens and around village huts².  Scientifically, it is called Ocimum gratissimum. It is widely distributed in tropical and warm temperature regions.

It is used commonly in folk medicine to treat different diseases such as upper respiratory tract infections, diarrhea, headache, pneumonia and also as a treatment for cough, fever and conjunctivitis^3,4.             

Ocimum is a genus of about thirty five species of aromatic annual and perennial herbs and shrubs in the family Lamiaceae, native to the tropical and warm temperate region of the old world. Ocimum gratissimum is one of the species from the genus. It is commonly called African basil or shrubby basil. It is Efinrin in Yoruba, Ebavbokho in Bini, Aai doya ta gida in Hausa and Nchonwu in Igbo⁵.

The chemical composition of Ocimum gratissimum are α–pinene,β-pinene, 1,8-cineole,Terpineole, Eugenol, (E)-β-Caryoplyllene, Muurolere, Sehirene and β -selinerel (Sainsbury and Sofowora⁶).                                                  

Erythrocytes (red blood cell) which are anucleate are packed with the oxygen carrying proteins hemoglobin. The normal concentration of erythrocytes in blood is approximately 3.9-5.5 million per micro liter in women and 4.1-6 million per micro liter in men.            

Human erythrocytes survive in the circulation for about 120 days, worn out erythrocytes are removed from the circulation by macrophages of the spleen and bone marrows. The signal for removal seems to be the appearance of defective complex oligosaccharides attached to integral membrane protein of the plasmalemma⁷.

Leukocytes (white blood cells) migrate to the tissue, where they perform multiple functions and most die by apoptosis.Leukocytes are involved in the cellular and humoral defense of the organism against foreign material.  The number of leukocytes in the blood varies according to age, sex and physiological conditions. In normal adults they are roughly 6,000-10,000 Leukocytes per micro liter of blood.           

Blood platelets (thrombocytes) are nonnucleated disk like cell fragments 2-4μm in diameter. Platelets originate from the fragmentation of giant polypoid megakaryocytes that reside in the bone marrow. Platelets count range from 200,000 to 400,000 per micro liter of blood. Platelets have a life span of about 10 days.Platelets function: the role of platelets in controlling hemorrhage can be summarized as primary aggregation, secondary aggregation, blood coagulation, clot retraction and clot removal. ⁷. Due to the widespread consumption of Ocimum gratissimum, it is necessary to study its effect on blood, the tissue that transports substances in the body 

 MATERIALS AND METHODS 

Animals

Twenty-five Wistar rats weighing between 100-160g were used for the study. The rats were purchased from the animal house of Biochemistry Department of University of Ilorin. They were bred for weeks in the animal house of Anatomy department of University of Ilorin. The rats were fed with pellets grower mash obtained from Bendel feed mill, Yoruba road, Ilorin and with water ad libitum during the breeding period designed to acclimatize the rats.

The rats were picked at random and grouped into five. A control group, while groups 1-4 were the experimental groups. Each of the rats were marked at the tail with different colours of pen marker and put into different segments of the cage, according to their group.

The rats were sacrificed after four weeks of extract administration using cervical dislocation. Blood from each rat was collected into labeled heparinized bottle to prevent coagulation of the blood.

Preparation of extracts

Fresh leaves of the plant Ocimum gratissimum were bought from Oja-Oba market in Ilorin. Botanical identification of the plants was done at the herbarium of the Botany Department of University of Ilorin.

The fresh leaves were kept in the oven at 80⁰c for ten minutes to stop any enzyme activity and then at 60⁰c for 30 minutes. They were collected from the oven, air dried and ground into coarse power. 50g of the powdered leaves was stirred into 450 ml of boiling distilled water.

Boiling was allowed to continue for five minutes, the mixture was then kept aside for thirty minutes to allow it to infuse. It was then filtered using a filter paper. The filterate was concentrated to 200ml (1ml of the extract being equivalent to 0.25g of the starting material). The extract was kept in a refrigerator until it was time to use.

Administration of extract

Administration of the aqueous extract was done orally by means of calibrated syringe with attached rubber cannula. The animals received their doses daily for four weeks.

Control group received a quantity of distilled water equivalent to the volume in group 4. Groups 1, 2, 3 and 4 received the aqueous extract of Ocimum gratissimum at doses of 0.2, 0.4, 0.8 and 1.6gkg^–1 respectively.

Hematological parameters

Evaluation of the hematological parameters was carried out using automated hematological Analyzer K-X- 21 made by Symex, Kobe, Japan.

Sample of blood from the wistar rats in heparinized bottle were analyzed using this machine for accuracy. Data obtained were analysed using t-test and chi square. Level of significance was predetermined as p< 0.05.

RESULTS 

The results of the effect of different doses of aqueous extract of Ocimum gratissimum on the haematological parameters are shown in Figs 1, 2, 3, 4.           

The machine analyzed blood samples to give about ten parameters, which include hemoglobin PCV, MCHC, RBC, MCH, MCV, WBC, platelets, Neutrophil and lymphocytes.

The mean Haemoglobin decreased significantly (p= 0.04) as compared with the control group as shown in Fig. 1. The mean packed cell volume (PCV) value in the treated animals was significantly reduced (p=0.031) at the end of the treatment period as compared with the control group (Fig. 2).

The mean corpuscular haemoglobin concentration also decreased as compared with the control. However this was not significant (p=0.066).The mean RBC count decreased significantly (p =0.0217) at the end of the treatment period as compared with the control group (Table 1). Both the mean corpuscular haemoglobin and the mean corpuscular volume decreased significantly as compared with the control (Table 1).

Table 1: Effect of aqueous extract of Ocimum gratissimum on RBC count, MCV and MCH

Table 2: Effect of aqueous extract of Ocimum gratissimum on WBC and platelets

Table 3: Effect of aqueous extract of Ocimum gratissimum on neutrophil

The white blood cell and platelets counts decreased in the experimental groups compared with the control group (Table 2). This was not statistically significant. There was no statistically significant decrease in the neutrophil count as compared with control group (Table 3). The Lymphocytes count also decreased (p=0.067) when compared to the control (Table 4).     

DISCUSSION

This work tested the effect of aqueous extract of Ocimum gratissimum on hematological parameters of wistar rats. The results of the study show that, the leaf extract of Ocimum gratissimum administered at the dosages used and for the duration of the experiment suppress the haemopoetic system.     

The hemoglobin values at the end of the experiment were 14.70 g/dl on the average for the control group and 12.95, 12.48, 12.15 and 10.72 g/dl on the average for the experimental groups. This shows a reduction in the hemoglobin level, this is in consonance with the finding of Ephraim et al⁸ in which the hemoglobin value decrease significantly after administration of aqueous extract of Ocimum gratissimum to rabbits.       

The packed cell volume at the end of the experiment for the control group is 42.7% on the average and 36.5, 34.75, 30.5, 27.2 % on the average for the experimental groups. This shows a decrease in the PCV value as compared to the control, this also agrees with the finding of Ephraim et al⁸.       

The mean corpuscular hemoglobin concentration (MCHC) at the end of the experiment gave a mean value of 40.0g/dl for the control group and mean value of 36.7, 33.5, 32.0 and 29.4 g/dl for the experimental groups. The result shows a decrease in the MCHC values in the experimental groups as was found by Ephraim et al⁸.

The red blood cell counts at the end of the experiment were 7.59x10¹²/L for the control group and mean values of 7.08, 6.92, 6.33, 5.57x10¹²/L for the experimental groups. These show a decrease in the red blood cell counts as compared to the control group, this is similar to the finding of Ephraim et al⁸. 

The mean corpuscular hemoglobin MCH at the end of the experiment is 20.67pg on the average for the control group and 19.75, 19.50, 19.50, 18.40 for the experimental group on the average. The MCH value decreases at the end of the experiment as compared to the control group value. This is also similar to the findings of Ephraim et al⁸.           

The mean corpuscular volume MCV at the end of the experiment is 57.67 fl on the average for the control group and 55.25, 53.25, 51.75, 50.80 on the average for the experimental groups. These values show a decrease in MCV value as compared to the control group; this is supported by the findings of Ephraim et al⁸.           

The white blood cell count give a mean value of 10.03x10⁹/L for the control group at the end of the experiment and a mean values of 8.03,6.65, 5.58, 4.08x10⁹/L for the experimental groups, a significant decrease in the WBC count was observed in the experiment group as compared to the control. Ephraim et al⁸ reported a decrease in WBC count by their work.           

The platelets count at the end of the experiment for the control group is 798.7x10⁹/L on the average and 660, 581.5 524.0, 384.0x10⁹/L on the average for the experimental groups. These values show a decrease in the platelets count as compared to the control group; this is similar to the findings of Ephraim et al⁸.           

The neutrophil level at the end of the experiment for the control group is 32.0% on the average and 30.0, 28.75, 25.25, 19.6% for the experimental groups on the average, a significant decrease on the neutrophil level was observed in the experimental groups as compare to the control. This is supported by the findings of Ephraim et al⁸.           

The lymphocyte level at the end of the experiment is 81.0% on the average for the control group and 77.0, 69.5, 66.6% for the experimental groups on the average. The lymphocyte level decreased at the end of the experiment as compared to the control group. This is supported by the findings of Ephraim et al⁸.

In conclusion, the study shows that the leaf extract of Ocimum gratissimum administered at the dosages used and for the duration of the experiment suppress the haemopoetic system. The reduction may have occurred due to lysis of blood cells and probably suppression of blood cell synthesis by saponins  found in the leaf extract⁹. Saponins are known to be toxic to body systems¹⁰. Despite of the popularity of the plant as a condiment and herbal medicine, the extract has been observed to suppress the haemopoetic system. It is therefore suggested that chronic usage of the leaf is not advisable.

REFERENCES

1. Oliver, B.  (1960) Medicinal plants in Nigeria. University of Ibadan, p358.
2. Iwu, M. M. (1993) Hand book of African Medicinal Plants, CRC press, New York. pp 214-215
3. Correa, M. P. (1932) Dicionario das plantos Uteis do Brasil IBDF Ministerio de Agricultura. Rio de Janeiro. 63.
4. Onajobi, F. D. (1986) Smooth muscle contracting Lipidic-soluble principle in chromatographic fractions of ocimum gratissimum. J Ethnopharmacol. 18:3-11.
5. Owulade, M. O. (2004) Handbook African medicinal plants, CRC Press, Boca Raton, Florida, USA. Page 214-215
6. Sainsbury, M. and Sofowora, E. A. (1971) Essential oil from the leaves and inflorescence of ocimum gratissimum. Photochemistry 10:3309-3310.
7. Janqueira, L. C. and J. Carneiro (2005) Basic Histology text and atlas, 10^th edition. Mc Grawhill, New York, pp 223-237
8. Ephraim, K. D., Salami, H. A. and Osewa, T. S. (2000)Effect of Aqueous leaf Extract of Ocimum gratissimum on Heamatological and Biochemical Parameters in Rabbits.  African Journal of Biomedical Research 3:175-179.
9. Irvine, F. R. (1961) Woody plants of Ghana with special references to their uses. London, Oxford University press, p868
10. Watt, J. M. and Breyer-Brandwijk, M. J. (1962) The medicinal and poisonous plants of Southern and Eastern Africa. 2^nd edition E and S. Livingston, Edinburgh. p1425

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