Antidiabetic Effect of Chloroform -Methanol Extract of Abrus Precatorius Linn Seed in Alloxan Diabetic Rabbit

The antidiabetic effect of chloroform – methanol extract of Abrus precatorious seed, was studied in alloxan diabetic rabbits. The effect was compared to that of chlorpropamide – a known antidiabetic drug in the class of sulphonylurea and a control group that received normal saline instead of the extract. Normal blood glucose levels drawn before the alloxan injection were 127.80 ± 2.55, 114.30 ± 4.17 and 123.60 ± 1.47 mg/100ml for chloroform – methanol, chlorpropamide and control respectively. When 50mg / kg body weight of chloroform – methanol, chlorpropamide and 5ml of normal saline for control were given orally, blood glucose levels decreased in chloroform – methanol and chlorpropamide groups of alloxan diabetic rabbits but not in control. The percentage reduction of blood glucose of chlorpropamide was 13.8, 32.3, 60.3, 53.5, 46.8, 46.3 and 46.2 after 05, 10, 20, 30, 40, 60 and 68 hours of oral administration respectively, while that of chloroform – methanol extract was 42.9, 58.7, 67.4, 69.1, 67.9, 56.6 and 51.8% respectively. The peak percentage reduction was 69.1% after 30 hrs. and 61.3% after 20 hrs. For chloroform – methanol extract and chlorpropamide respectively. This study therefore has shown that the chloroform – methanol extract of Abrus precatorius seed has some antidiabetic properties similar to that of chlopropamide. This is shown in their similar percentage reduction in blood glucose level. @JASEM Diabetes mellitus is a group of metabolic disorders that result in hyperglycemia due to decreased insulin production or inefficient insulin utilization. The World Health Organization predicted that the number of diabetic patients will double from 143 million in 1997 to about 300 million in 2025 largely because of dietary and other lifestyle factors (Seidell, 2000). The incidence of type II diabetes is closely linked to choice of diet leading to overweight or obesity (Wannamethee and Shaper, 1999). About 75% of diabetes is type II or non – insulin dependent diabetes (NIDD) (Barnett, 1991) and is associated to other disease conditions like obesity (Wolf and Colditz, 1998); coronary heart, eye, renal, vascular and neurological problems (Miller, 1991). The use of most synthetic antidiabetic drugs like sulfonylurea, biguanides and intravenous insulin injections have their own disadvantages. The most important side – effect of sulfonylureas is hypoglycaemia (Berger, 1985). The severe hypoglycaemia can lead to death. Insulin injection takes place intraveneously. This is because insulin is frequently destroyed in the gastrointestinal tract. Insulin degradation and presence of insulinase were also reported by many authors (Kitabchi and Stentz, 1972; Kahn et al 1976). There is therefore need for oral substitutes for both insulin and severe hypoglycaemic antidiabetic drugs in management of diabetes. Several botanical supplements have been studied as potential therapeutic agents in the management of diabetes and its related complications. The use of legumes in this effect was reported by many authors. Legumes like Trigonella foemum graecum ( Festrow and Avila, 1999; Sharma, et al., 1996), Pterocarpus marsupium, (Meries and Farnsworth, 1995), Vigna unquiculata (Tella and Ojihomon, 1980) have been in use. Jenkins, et al. (1981) showed that legume whole seed or extracts could be helpful in reducing the high blood sugars in diabetes because of their low glycaemic index. Abrus precatorius is a tropical legume found in the forests of Nigeria. The seed extracts of Abrus Precatorius was reported by Nwodo and Alumanah (1991) as an antidiarrhoeal agent in mice. Uterotonic activity of the seed in rats was reported by Nwodo and Botting, (1983). The report of chemical composition by Nwodo and Botting, (1983) showed that Abrus precatorius contain some substances in the chloroform – methanol extract of the seed, that are likely to reduce the blood glucose level. We therefore studied the antidiabetic properties of the chloroform – methanol extract of the seed of this plant. The aim is to know whether it can be used in the management of diabetes melitus M ISSN 1119-8362 All rights reserved J. Appl. Sci. Environ. Mgt. 2005 Vol. 9 (1) 85 88 Full-text Available Online at http:// www.bioline.org.br/ja *Corresponding author Email: [email protected] Antidiabetic effect... Monago and Alumanah 86 MATERIALS AND METHODS Sample Preparation: Fresh seeds of Abrus precatorius were collected from a local source. The seeds were collected from the pods, cleaned and ground to fine powder with a high speed blender (Mill size 8). The ground seed was stored dry and used throughout the study. A known weight of the sample was soaked in chloroform – methanol (2:1) and extracted for 18 hours in a container on a flaskshaker (Gallenkamp). The mixture was filtered and the filtrate was re-extracted with equal volume of water and evaporated to dryness. The crude extract is regarded as chloroform – methanol extract chloroform – methanol. Chlorpropamide a known sulfonylurea was bought from the market and used as a control for antidiabetic drugs. Treatment of Animal: Three groups of male healthy rabbits (n = 3) with average weight of 1.6kg were used. Food, water, ambient temperature and proper ventilation were allowed throughout the study. Alloxan (180mg/kg body weight) was injected intraperitoneally to all the rabbits. They were allowed for 72 hours for full development of diabetes. After 72 hours, hyperglycaemic glucose level was determined using O-toluidine method. Then oral administration of 50mg/kg body weight of the chloroform – methanol extract, chlorpropamide and 5mls of normal saline as control were given respectively. Collection and Determination of Blood Glucose Levels: Blood was drawn after 5, 10, 20, 30, 40, 60 and 168 hours of oral administration of chloroform – methanol extract, chlorpropamide and control. The blood was drawn from the ear vein and transferred to NaF/oxalate bottle. The blood was centrifuged at 2000g for 10 minutes. Blood glucose level was determined using O-toluidine method of Frings, et al (1970). Statistical analysis was done using students T – test. Data obtained were analyzed as mean ± standard error of mean. Values were considered significant at P<0.05 and P< 0.001. RESULTS AND DISCUSSION The chloroform – methanol extract of Abrus precatorious seed showed a marked blood glucose reduction especially after 30 hours of oral administration. Table 1.0 and fig. 1.0 show the relative blood glucose reduction compared to chlorpropamide a known sulfonylurea and a control group control. The peak percentage reduction of chloroform – methanol was 69.1% after 30 hours while that of chlorpropamide was 61.3% after 20 hours of administration. The blood glucose percentage reduction was 42.9, 58.7, 67.4, 69.1, 67.9, 56.6 and 51.8 after 05,10,20,30,40,50,60 and 168 hours respectively; while that of chlorpropamide was 13.8, 32.3, 61.3,33.5,46.8, 46.5 and 46.2% respectively. There was a significant difference (P<0.001) between the reduction parttern of chloroform – methanol to that of chlorpropamide. When chloroform – methanol was however compared to control, there was no significant difference after each time of blood collection except after 05 minutes which was significant at P<0.001. Also chlorpropamide did not show any significant difference when compared with control except after 05 (P<0.05) and 40 hours (P<0.001) of blood collection. Table 1. Effects of cm, cp and co in alloxan diabetic rabbits blood glucose levels (mg/100ml) SAMPLE Hyperglycemic level TIME – (HOURS) 0 5 10 20 30 40 60 168 CM 261.50 ±2.08c 149.46 ± 4.74cf 108.00 ± 720bf 85.20 ± 2.08a 81.00 ± 2.56c 83.70 ±2.85cf 113.40 ±1.63b 126.00 ±2.01a Reduction from baseline 11204 153.50 176.30 180.50 177.80 148.10 % Reduction 100 429 587 674 691 679 566 518 CP 234.03 ±0.80 201.60 ±1.09df 158.40 ±1.05f 92.90