Phytochemical composition of the crude extract of
Diabetes is a major metabolic disease of global concern. Ethanolic extract of Corchorus olitorius leaf was investigated for antidiabetic activity in alloxan-induced diabetic rats. A total of thirty-six albino rats (Rattus norvegicus) with body weight 150.50 ± 10.50 g were randomly selected into six groups (A–F). Group A animals were non-diabetic and received 0.5 mL distilled water, groups B, C, D, E and F were made diabetic by administration of alloxan monohydrate (150 mg/kg, body weight i.p). Group B was diabetic untreated, group C was diabetic and treated with glibenclamide, while groups D, E and F received the ethanolic extract of C. olitorius leaf at a dose of 200 mg/kg, 400 mg/kg and 800 mg/kg body weight respectively. Phytochemical screening showed the presence of flavonoids, tannins, saponins, phlobatannin anthraquinones, phenol and cardiac glycoside and saponin. The blood glucose of the alloxanized rats after 72 hours which ranged from 17.30–25.33 mmol/L were significantly (p < 0.05) and progressively reduced in treated groups which compared favorably with the standard drug group. The significantly (p < 0.05) elevated levels of serum and liver bilirubin (direct and total), transaminases (AST and ALT), alkaline phosphatase, urea, creatinine, total cholesterol, triglyceride, LDL-C, as well as reduced levels of total protein, globulin, albumin and HDL-C in the diabetic untreated rats were normalized upon treatment with ethanolic extract of C. olitorius leaf. These results suggest that the ethanolic extract of C. olitorius leaf possesses antihyperglycemic property with no major side effect hence it could be considered safe for the management of diabetes.
- Corchorus olitorius
- blood glucose
Diabetes is a chronic disease that occurs either when the pancreas does not produce enough insulin (a hormone that regulates blood sugar, or glucose), or when the body cannot effectively use the insulin it produces. Diabetes mellitus (DM) presents enormous and increasingly important public health issues as it is listed among the commonest non-communicable diseases (NCDs) globally, the prevalence of which increased in adults from 4.7% in 1980 to 8.5% in 2014. Diabetes mellitus led to about 1.5 million deaths in 2012. Elevated blood glucose resulted into an additional 2.2 million deaths through complications arising from heart related diseases. Over 43% of these deaths were recorded before the seventh decade of life [1, 2]. Prevalence of DM in Africa is approximately 1% in rural areas and up to 7% in urban sub-Sahara Africa . In Nigeria, DM is estimated to be between 0.9–15% .
The percentage of deaths attributable to high blood glucose or diabetes that occurs prior to age 70 is higher in low- and middle-income countries than in high-income countries. The disease is characterized by high blood glucose levels and abnormal metabolism of carbohydrates, proteins, and fat associated with a relative or absolute insufficiency of insulin secretion and with various degrees of insulin resistance. Such alterations result in increased blood glucose causing a chronic state of high blood glucose level (hyperglycemia) that results from an absolute or relative insulin deficiency and is associated with long-term complications affecting the eyes, kidneys, heart and nerves .
Cellular stress as a result of reactive oxygen species such as peroxyl (ROO), nitrogen dioxide (NO2−), superoxide (O2.−), nitric oxide (NO.), hydroxyl (OH−) and non-free hydrogen peroxide and singlet oxygen radicals play a significant role in the pathogenesis of several disease conditions such as DNA damage, cellular degeneration and oxidation of lipids and proteins. These have been implicated in the development of these diseased conditions associated with diabetes [6, 7, 8, 9].
The pathogenesis of diabetes mellitus is managed by insulin and oral administration of hypoglycemic drugs such as sulfonylureas and biguanides which are not without a number of side effects. Moreover, none of the oral synthetic hypoglycemic agents has been successful in diabetes management and controlling long-term microvascular and macrovascular complications . The toxicity of oral antidiabetic agents differs widely in clinical manifestations, severity, and treatment .
Optional therapies such as herbal preparations have been used for the management of diabetes. The benefits of these herbal medications are their efficacy, endogenous relativity, cost effectiveness and tolerability . Various parts of medicinal trees have been employed in the third world traditional medicinal system and most have demonstrated pre-clinical or clinical normoglycemic activity . Furthermore, World Health Organization has also recommended the evaluation of traditional plant treatments for diabetes .
2. Materials and methods
Alloxan monohydrate obtained is a product of Sigma Chemical Company, St. Louis, Mo, USA. Kit for the estimation of AST, ALT, urea, creatinine and bilirubin, were produced by Randox Laboratories Ltd., Antrim, UK. All other chemicals were of analytical grades and prepared in all-glass apparatus using distilled water (BDH, UK).
2.1. Plant extract preparation
The fresh leaves of
2.2. Experimental animals
A total of thirty-six (36) Albino rats (
2.3. Induction of diabetes
The animals were fasted overnight and diabetes was induced by a single intraperitoneal injection of freshly prepared 150 mg/kg b.w alloxan monohydrate dissolved in (5%) sterile saline. Two days after alloxan injection, rats with blood glucose level of >12 mmol/L were separated and considered diabetic and were used for the study. Blood glucose levels were measured using blood glucose test strips with fine test glucometer (infopia Co. limited Korea). The treatment started 48 hours after alloxan injection and this was considered the first day of treatment. The treatment continued for 14 days.
2.4. Animal grouping and extract administration
Animals were divided into six groups, and for each group, six animals were treated orally once a day for 14 days as follows:
Group A: Control rats received distilled water only.
Group B: Diabetic control.
Group C: Diabetic rats received Glibenclamide at a dose of 5 mg/kg.
Group D: Diabetic rats received 200 mg/kg body weight extract.
Group E: Diabetic rats received 400 mg/kg body weight extract.
Group F: Diabetic rats received 800 mg/kg body weight extract.
2.5. Samples preparation
At the end of the experimental period, food was withdrawn from the rats and they were fasted overnight while the animals had free access to water. They were then euthanized under diethyl ether vapor and sacrificed. Venous blood was collected from the experimental animals and serum was prepared by centrifuging the blood samples at 3000 rpm for 5 minutes and serum collected by pipetting. The animals were quickly dissected and internal organs including liver and kidney were collected, blotted using filter paper to remove traces of blood and then weighed with an analytical balance. The pancreas, liver and kidney were suspended in ice-cold 0.25 M sucrose solution (1:5 m/v) and homogenized as described by Akanji and Yakubu .
2.6. Statistical analysis
Comparisons were made using Duncan’s multiple range test, and values were considered to be significant at p < 0.05.
3.1. Phytochemical constituents of ethanolic extract of
Table 1 shows the results of the preliminary phytochemical analysis of the leaf extract. Analysis revealed the presence of alkaloids, flavonoids, tannins, saponins, phlobatannin anthraquinones, phenol, cardiac glycoside and saponin while Terpenoids, Steroids, Triterpenes were not detected.
3.2. Glycemic effect of ethanolic extract of
Corchorus olitoriusleaf of alloxan-induced diabetic rats
Table 2 presents the glycemic effects of ethanolic extract of
|Treatment groups||Fasting blood glucose level after diabetes induction|
|Day 0||Day 5||Day 10||Day 14|
|Control||5.13 ± 0.60a||4.00 ± 0.70a||4.38 ± 0.20a||4.13 ± 0.29a|
|Diabetic rats + distilled water||17.03 ± 1.70b||19.18 ± 1.11b||18.83 ± 1.25b||20.41 ± 1.07b|
|Diabetic rats + Gliblenclamide||21.68 ± 1.93b||16.05 ± 0.72b||12.10 ± 0.29ab||5.80 ± 0.35a|
|Diabetic rats +200 mg/kg body weight of the extract||18.43 ± 1.04b||14.58 ± 0.55b||13.08 ± 0.44ab||9.43 ± 0.26ab|
|Diabetic rats +400 mg/kg body weight of the extract||20.80 ± 2.46b||13.63 ± 0.21b||12.30 ± 0.81ab||7.88 ± 0.63ab|
|Diabetic rats +800 mg/kg body weight of the extract||25.33 ± 1.91b||22.95 ± 1.41b||13.43 ± 1.10ab||6.05 ± 0.66a|
3.3. Effect of ethanolic leaf extract of
Corchorus olitoriuson body weight of alloxan-induced diabetic rats
In diabetic rats, continuous reduction in body weight was observed as shown in Table 3. Glibenclamide (5 mg/kg) as well as the extract treatment groups at the dose of 400 and 800 mg/kg b.w showed improvement (P < 0.05) improvement in body weight of diabetic rats.
|Treatment groups||Initial body weight (g)||Final body weight (g)|
|Control||136.25 ± 10.33a||180.07 ± 13.07b|
|Diabetic rats + distilled water||172.67 ± 5.10b||134.01 ± 13.17a|
|Diabetic rats + Gliblenclamide||153.33 ± 1.55ab||184.22 ± 8.46b|
|Diabetic rats +200 mg/kg body weight of the extract||157.25 ± 3.07ab||164.08 ± 10.56ab|
|Diabetic rats +400 mg/kg body weight of the extract||175.67 ± 14.06b||183.19 ± 14.79b|
|Diabetic rats +800 mg/kg body weight of the extract||141.42 ± 4.47ab||172.69 ± 10.70b|
3.4. Effect of ethanolic leaf extract of
Corchorus olitoriuson liver function enzymes of alloxan-induced diabetic rats
The effect of ethanolic leaf extract of
3.5. Effect of ethanolic leaf extract of
Corchorus olitoriuson some biochemical parameters of alloxan-induced diabetic rats
Figures 3 and 4 show the effect of administration of ethanolic leaf extract of
The diabetic untreated rats group had decreased levels of serum and liver total protein, albumin and globulin when compared with normal control rats. After treatment for 14 days, liver and serum total protein, albumin and globulin levels were restored to normalcy especially in the groups treated with 800 mg/kg body weight of the extract and reference drug (gliblenclamide).
3.6. Effect ethanolic leaf extract of
Corchorus olitoriuson kidney function indices of alloxan-induced diabetic rats
The influence of administration of ethanolic leaf extract of
3.7. Effect of administration of ethanolic leaf extract of
Corchorus olitoriuson liver lipid profile of alloxan-induced diabetic rats
The effect of oral administration of ethanolic leaf extract of
The therapeutic cure for diabetes mellitus has remained elusive despite the discovery of an array of medications that can ameliorate the symtopms of the disease . Phytotherapies have remained a veritable source for drug discovery the world over , and for some decades have played an important role in the management of diabetes especially in resource poor countries.
Alloxan acts as diabetogenic by the destruction of β-cells of the islets of langerhans and causes massive reduction in insulin release, thereby inducing hyperglycaemia . Insulin deficiency leads to various metabolic alterations in the animals viz. increased blood glucosel, increased levels of alkaline phosphate and transaminases etc. .
Phytochemical investigation of ethanolic leaf extract of
Single dose intra-peritoneal (i.p) treatment of rats with alloxan monohydrate (150 mg/kg) caused an increase in the blood glucose. Ethanolic leaf extract of
The concentration of total protein globulin, albumin and bilirubin may indicate the state of the liver and type of damage. Protein molecules that are regularly employed to assess the state of health of the liver are albumins and globulins (Total Proteins). The blood circulated albumin is the main carrier protein produced in the liver. The larger globulins are responsible for immunogenic activities . Decreased serum albumin and globulin concentrations in the untreated diabetic rats suggests reduced synthetic function of the hepatic cells. Oral administration of ethanolic leaf extract of
Bilirubin is a useful index of the excretory function of the liver. It is an important breakdown product of blood with biological and diagnostic values  Elevated bilirubin is an indication of liver cell impairment. The gradual increase in the serum levels of unconjugated (total and conjugated) bilirubin in diabetic rats when compared with the normal control may be an indication that the rats had liver function impairment, resulting in diminished ability of hepatocytes to conjugate bilirubin. The insignificant decrease in total and conjugated bilirubin of both the serum and liver in all the treated animals suggest the ability of the plant extract to ameliorate liver impairment caused by diabetes induction.
Liver enzymes e.g. alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alanine phosphatise level (ALP) were increased in diabetic rats which is responsible for the liver damage. The elevated serum level of these enzymes was significantly reduced by ethanolic leaf extract of
The kidney removes metabolic wastes such as urea and creatinine, the concentration of which are usually required to assess the normal functioning of different parts of the nephrons . The serum creatinine and urea concentrations are widely interpreted as measures of the glomerular filtration rate (GFR) and are used as indices of renal function in clinical practice. The concentration of these metabolites increase in blood during renal damage associated with uncontrollable diabetes mellitus. On the contrary those treated with ethanolic leaf extract of
Inbalances in serum lipid levels are usual occurrences in a diabetic state . Since changes in lipoproteins concentrations is an inherent property of diabetes mellitus, such changes are usually triggered by diabetes induced obesity and renal complications . As observed in this study, administration of ethanolic leaf extract of
The present study showed that the ethanolic extract of
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