|Year : 2014 | Volume
| Issue : 2 | Page : 66-73
Extracts of Hunteria umbellata reverses the effect of streptozotocin-induced pancreatic islet-cell destruction
Oghenakogie I Momodu, AB Enogieru, Sylvester I Omoruyi, F. A. E. Om`Iniabohs
Department of Anatomy, School of Basic Medical Sciences, College of Medical Sciences, University of Benin, Benin City, Edo State, Nigeria
|Date of Web Publication||1-Apr-2015|
Oghenakogie I Momodu
Department of Anatomy, School of Basic Medical Sciences, College of Medical Sciences, University of Benin, Benin City, Edo State
Source of Support: None, Conflict of Interest: None
The use of extracts of plant parts in the treatment and/or management of diabetes mellitus has formed the basis of health care in most African countries. The aim of this study was to investigate the possible effect of oral administration of extracts Hunteria umbellata (HU) leaves and seeds on streptozotocin- induced pancreatic β-cell damage. Twenty four (24) adult wistar rats were selected into two control group (negative control group A and positive control group B) and two treatment groups (C & D) each containing six animals each (n= 6 per group). Rats in the positive control group (B) were giving intraperitoneal injection of with 50 mg/kg body weight of Streptozotocin (STZ) prepared with 0.05M Citrate buffer solution while the negative control group A rats were injected with a corresponding volume of Citrate buffer without STZ. Rats in the treatment groups were treated with 250 mg/kg body weight aqueous extract of seeds of Hunteria umbellata (group C) and 250 mg/kg body weight aqueous extract of leaves of Hunteria umbellata (group D) respectively. Blood samples were taken by repeated needle puncture of their tail tip vein every 72 hours at the end of a 12 hrs fasting. Fasting blood glucose was determined using a fine test glucometer and compatible glucose test strips. Rats were sacrificed by cervical dislocation on the 15 th day and the pancreas was accessed and dissected out through a midline incision of the anterior abdominal wall of the rats. The pancreas was fixed in 10% buffered formal saline for routine histological examination. 5ml blood samples were collected in heparin coated tubes for serum anti-oxidant estimation. Results obtained showed that HU seeds and leaves extracts significantly (P < 0.05) increased Superoxide dismutase (SOD) and Catalase (CAT) activities and decrease in the activity of Thiobarbituric acid reactive species (TBARS) when compared streptozotocin injected rats. Histological sections showed marked distortion, vacoulation of the central part of the Islet. Treatment with Hunteria umbellata seed and leaf extracts reversed the cytoarchitectural distortion of pancreatic Islet cells caused by Streptozotocin. This suggests that extracts of HU seeds and leaves posses antidiabetic potential.
Keywords: Hunteria umbellata , streptozotocin, pancreatic Islet, cytoarchitectural distortion
|How to cite this article:|
Momodu OI, Enogieru A B, Omoruyi SI, Om`Iniabohs F. Extracts of Hunteria umbellata reverses the effect of streptozotocin-induced pancreatic islet-cell destruction. J Exp Clin Anat 2014;13:66-73
|How to cite this URL:|
Momodu OI, Enogieru A B, Omoruyi SI, Om`Iniabohs F. Extracts of Hunteria umbellata reverses the effect of streptozotocin-induced pancreatic islet-cell destruction. J Exp Clin Anat [serial online] 2014 [cited 2021 Jan 27];13:66-73. Available from: https://www.jecajournal.org/text.asp?2014/13/2/66/154404
| Introduction|| |
Intracellular actions of streptozotocin (STZ) result in changes of DNA in pancreatic β-cells comprising its fragmentation (Yamamoto et al., 1981; Morgan et al., 1994). Recent experiments have proposed that the main reason for STZ-induced β-cell death is the alkylation of DNA (Delaney et al., 1995; Elsner et al., 2000). The alkylation activity of STZ is related to the nitrosourea moiety especially at the O 6 position of guanine. After STZ injection to rats, different methylated purines were found in tissues of these animals (Bennett and Pegg, 1981). STZ is a nitric oxide (NO) donor and NO is found to bring damage to pancreatic β-cells (Morgan et al., 1994; Kroncke et al., 1995). The participation of NO in the cytotoxic effect of STZ was confirmed in several experiments (Turk et al., 1993; Kroncke et al., 1995). Pancreatic β-cells exposed to STZ manifested changes characteristic for NO action that is, increased activity of guanylyl cyclase and enhanced formation of cGMP (Turk et al., 1993). STZ is however not a spontaneous NO donor (Kronke et al., 1995). This molecule is liberated when STZ is metabolized inside the cells, but NO synthase is not required (Kronke et al., 1995). On the other hand, the lowering of NO concentration in pancreatic islet cells by inhibition of inducible forms of NO synthase partially counteracted DNA cleavage induced by STZ (Bedoya et al., 1996). A similar result can be attained by NO scavengers (Kroncke et al., 1995). However, the result of several experiments provide the evidence that NO is not the only molecule responsible for the cytotoxic effect of STZ. STZ was found to generate reactive oxygen species (ROS), which also contributes to DNA fragmentation and evoke other deleterious changes in the cells (Takasu et al., 1991; Bedoya et al., 1996). The formation of superoxide anions results from both STZ action on mitochondria increase activity of xanthine oxidase. It was demonstrated that STZ inhibits the Krebs cycle (Turk et al., 1993) and substantially decreases oxygen consumption by mitochondria (Nukatsuka et al., 1990). Augmented adenosine triphosphate (ATP) dephosphorylation increases the supply of substrate for xanthine oxidase (β- cells posses` high activity of this enzyme) and enhances the production of uric acid the final product of ATP degradation (Nukatsuka et al., 1990). Then the xanthine oxidase catalyses` reaction in which the superoxide anion is formed (Nukatsuka et al., 1988). As a result of superoxide anion generation of hydrogen peroxide and hydroxyl radicals are formed (Nukatsuka et al., 1990; Takasu et al., 1991). The inhibition of xanthine oxidase by allopurinol restricts the cytotoxic effect of STZ in vitro. It can be stated that potent alkylating properties of STZ are the main reason of its toxicity (Nukatsuka et al., 1990). However, the synergistic action of both NO and ROS may also contribute to DNA fragmentation and other deleterious changes caused by STZ. Therefore, inhibition of intracellular ROS or NO production can substantially restrict STZ toxicity and reverse STZ induced pancreatic β-cell destruction.
Hunteria umbellata (HU) K. Kchum (Apocynaceae) is a small tree of about 15-22 m in height with a dense evergreen crown (Oliver, 1986). It is found in rain forest zone of the southern part of Nigeria where it bears such local names as Osu (Edo), Erin (Yoruba) and Nkpokiri (Ibo) (Boone, 2006). It is also found in Ubongi-Shari in Ghana and the rain forest regions of Cameroon and Gabon. The leaves have been described as broad, abruptly acuminate and broadly lineate (Kaey and Onochie, 1964; Boone, 2006). The fruit is about 5-25 cm in diameter and consists of two separate globose mericaps 3-6 cm long, yellow, smooth. 8-25 seeds embedded in a gelatinous pulp (Kaey and Onochie, 1964).
Hunteria umbellata have been widely employed in traditional herbal medicine in the treatment of peptic ulcers, piles yaws, dysmenorrhea, fever, infertility (Eluojoba, 1995), helminthic infection (Oluwemimo and Usifoh, 2001), bacterial infection (Anibijuwon et al., 2011) and Diabetes (Igbe et al., 2009). Recent research on the use of extracts of HU focuses on its use as a potent antidiabetic agent (Igbe et al., 2009; Adeneye et al., 2010). In spite of its use as a potent antidiabetic agent little is known of the possible mechanism behind its antidiabetic potentials. This present research focusses on investigation of the possible mechanism behind the use of HU in the treatment of diabetes.
| Materials and methods|| |
The seeds and leaves HU were collected from a farmland in Efon, a town near Benin City. The plant was identified by Mr. Nweke Sunny, a Curator at the Department of Pharmacognosy, Faculty of Pharmacy, University of Benin, Benin City.
Preparation and Phytochemistry of Extract
The seeds as well as leaves of HU (K Schum) plants were sun dried for 8 weeks. The air-dried specimens were pounded using a wooden mortar and pestle and milled into fine powder in an electric blender A quaintly of 500 g of the powdered specimens was extruded in distilled water by percolation for 48 h. The mixture was filtered, and the filtrate evaporated at 60°C using a vacuum Rotary evaporator. A pasty residue was freeze-dried using a vacuum freeze drier and stored in a desiccator. An aliquot portion of the crude extract residue was dissolved in distilled water for use on each day of the experiment.
Animals and Treatment Regimen
Twenty-four Adult Wistar rats were used for the experiment. The rats were selected into two control group (negative control Group A and positive control Group B) and two treatment Groups C and D each containing six animals each (n = 6 per Group). The rats in each group were giving 300 g/day Growers' mash and water ad libitum. Rats in the positive (STZ-injected rats) control Group B were injected with 50 mg/kg body weight of STZ intraperitoneally prepared with 0.05 M citrate buffer solution (Akbarzadeh et al., 2007) while the negative (non-STZinjected) control Group A rats were injected with a corresponding volume of Citrate buffer without STZ. Rats in the treatment groups were injected with 50 mg/kg body weight of STZ and treated with 250 mg/kg body weight aqueous extract of seeds of HU (Group C) and 250 mg/kg body weight aqueous extract of leaves of HU (Group D) respectively. The extracts were administered orally using an Orogastric tube.
Procedure for Pancreatic islet-cell Destruction
Islet Cell destruction was induced by a single intraperitoneal injection of 50 mg/kg body weight STZ dissolved in 0.05 M sodium citrate buffer (pH - 4.6). Rats in Group A were given corresponding volume of citrate buffer used in dissolving STZ intraperitoneally. The extent of Islet cell damage and recovery was assessed during the experimental period by determination of fasting blood glucose (FBG) concentration from blood samples obtained by repeated needle puncture of their tail tip vein after every 72 h following a 12 h fasting. Fasting glucose concentration in the blood samples was determined using a fine test glucometer and compatible glucose test strips. All animals were kept and maintained under laboratory conditions of light, humidity and temperature.
Sacrifice of the Animals
Animals received treatment for 14 days. FBG concentration was taken on the 15 th day, and animals were sacrificed by cervical dislocation. A midline incision was made through the anterior abdominal wall of the rats. 5 ml blood samples were collected, from the descending abdominal aorta, in heparin coated tubes for serum antioxidant estimation and the pancreas were excised and a part washed in normal saline for tissue antioxidant estimation, and the other part was fixed in 10% buffered formal saline for routine histological examination.
Blood samples were collected in heparin coated tubes and pancreas was place in 5 ml of normal saline. Centrifugation was done using a Denley BS400 Euslaw centrifuge at 4°C and 5000 rpm for 5 min. Superoxide dismutase (SOD) determination, using Randox Assay Kits manufactured by Randox Laboratories ltd, Ireland, Uk as described (Fridovich, 1974), which were based on the production of O anions by the 2-xanthine/xanthine oxidase system. The activity of catalase (CAT) was measured in the homogenates by measuring the CAT degradation of hydrogen peroxide using a redox dye according to methods of Cohen et al., 1970. The assay was carried out in a visible spectrum microplate reader (DNM-9602 Perlong Beijing) which measures the change in color intensity of degradation at 570 nm. The change in color intensity is directly proportional to the CAT activity in the sample. Plasma concentrations of thiobarbituric acid reactive species (TBARS) were determined using the Malondialdehyde Assay Kits according to the method of Buege and Aust, 1978.
Procedure for hematoxylin and eosine was carried out according to the method of Drury and Wallington (1980).
The sections were examined under Leica DM750 research microscope with a digital camera (Leica ICC50) attached. Digital photomicrographs of the tissue sections were taken at ×400 magnifications. Pancreatic islet cells in the photomicrographs were cropped at 369 × 348 pixels in Microsoft Office Picture manager manufactured by Microsoft corporation, Redmond, Washington and counted using the counter window of IMAGE J software with RGB color developed by the National Institute of Health, Maryland, USA.
The data were analyzed using descriptive and inferential statistics. All values were presented as mean ± standard error of the mean for six rats each of four groups. The significance of the difference in the means of all parameters was determined using one-way analysis of variance (95% confidence interval). Least Square difference, post-hoc tests was carried out for all groups with control and comparison of all pairs of groups respectively. All statistical analysis was carried out using Statistical package for Social Sciences (SPSS) (version 16) manufactured by international Business Machine Corporation (IBM) in Armonk, New York.
The animals were housed, fed and cared for in accordance with the guidelines of the School of Basic Medical sciences ethical committee. The research was approved by the research ethics committee of the School of Basic Medical sciences , University of Benin, Benin city.
| Result|| |
Effects of Hunteria unbellata Seeds and Leaves on Fasting Blood Glucose Concentration
The FBG concentration is shown in [Figure 1]. FBG concentration of rats in a negative control Group A fluctuated within normal range (78.67 ± 5.26 mg/dl vs. 78.33 ± 2.33 mg/dl) during the experimental period of 14 days. This fluctuation was insignificant (P < 0.05). Rats in the positive control Group B showed significantly (P < 0.05) elevated FBG concentration (424.33 ± 16.82 mg/dl vs. 520.33 ± 18.7 mg/dl) during the experimental period. The FBG concentration of the treatment Groups C and D dropped (185.0 ± 4.83 mg/dl vs. 167.06 ± 1.39 mg/dl and 191.67 ± 5.27 mg/dl respectively). Group C showed a significant (P < 0.05) drop while Group D showed an insignificant (P < 0.05) drop.
|Figure 1: Line graph showing sequential (a) changes in fasting blood glucose (FBG) concentration of rats in Group A. (b) Changes in (FBG) concentration of rats in Group B. (c) Changes in (FBG) concentration of rats in Group C. (d) Changes in FBG concentration of rats in Group D|
Click here to view
Effects of Hunteria unbellata on the Antioxidant Profile
The Bar Chart below illustrates the activities of SOD, CAT, and malondialdehyde (MDA) in serum and pancreas of STZ-induced diabetic rats treated with aqueous extracts of HU seeds as well as leaves. The activity of SOD in serum and pancreas of Group B rats was significantly (P < 0.05) low (70.24 ± 4.05 μ/ml and 49.27 ± 5.29 U/ml respectively) when compared with control Group A, non-induced, negative induced, control rats, (103.60 ± 5.4 U/ml and 108.97 ± 4.32 U/ml respectively). There was increased SOD activity in Serum and pancreas Group C (STZ-induced diabetic rats treated with aqueous extract of HU seeds) rats (102.41 ± 4.83 U/ml and 86.31 ± 7.3 U/ml) and Group D (STZ-induced diabetic rats treated with aqueous extract of HU leaves) rats (104.83 ± 3.11 U/ml and 103.17 ± 5.54 U/ml).These increases were significant (P < 0.05) when compared with the control B (STZ-induced diabetic, positive induced, control rats) but not significant when compared with the control A.
The Bar Chart in [Figure 2]c and d shows CAT activities in the serum and pancreas. The CAT activity of positive control Group B was significantly (P < 0.05) lowered in serum and pancreas (0.57 ± 0.12 U/L and 0.40 ± 0.08 U/L respectively) when compared with negative control Group A (1.57 ± 0.35 U/L and 0.90 ± 0.10 U/L respectively). On treatment with aqueous extract of HU leaves (treatment Group D), there was an insignificant (P < 0.05) increase (1.13 ± 0.18 U/L) in serum CAT activity when compared with both positive control Group B (0.57 ± 0.12 U/L) and negative control Group A (1.57 ± 0.35 U/L) but increased significantly (P < 0.05) in pancreas (0.99 ± 0.11 U/L) when compared with control Group B. The CAT activity of treatment Group C (STZ-induced rats treated with aqueous extract of HU seeds) significantly (P < 0.05) increased (1.51 ± 0.31 U/L) in serum when compared with positive control Group B and insignificantly (P < 0.05) increased with negative control Group A. Although CAT activity increased (0.68 ± 0.04 U/L) in pancreas of Group C but the increase was not significant (P < 0.05) when compared with negative control Group A and positive control Group B.
|Figure 2: Bar Charts showing (a) serum superoxide dismutase (SOD) activity of streptozotocin (STZ)-induced diabetic rats treated with extract of Hunteria umbellata. (b) SOD activity in pancreas of STZ-induced diabetic rats treated with extracts of Hunteria umbellata. (c) Serum catalase (CAT) activity of STZ-induced diabetic rats treated with extracts Hunteria umbellata. (d) CAT activity in pancreas of STZ-induced diabetic rats treated with extracts of Hunteria umbellata. (e) Serum thiobarbituric acid reactive species (TBARS) activity of STZ-induced diabetic rats treated with extracts of Hunteria umbellata. (f) TBARS activity in pancreas of STZ-induced diabetic rats treated with extracts of Hunteria umbellata.*' and '#'represents significance of mean values when compared with control A and B respectively using Bonferroni multiple comparison test|
Click here to view
The concentration of TBARS in serum and Pancreas is evaluated and shown in [Figure 2]e and f. TBARS concentration in Serum and pancreas was significantly (P < 0.05) higher (15.32 ± 0.79 μM MDA and 18.33 ± 1.01 μM MDA respectively) in Group B than negative control Group A (7.63 ± 0.39 μM MDA and 7.14 ± 0.38 μM MDA respectively). TBARS concentration in serum and pancreas of treatment Groups C (10.82 ± 0.78 μM MDA and 11.55 ± 0.81 μM MDA respectively) and D (8.62 ± 0.76 μM MDA and 8.72 ± 0.78 μM MDA respectively) was higher than Group A. The comparison with treatment Group C was significantly (P < 0.05) higher, comparison with treatment Group D was not significant (P < 0.05).
Effect on Histology of Pancreas Islets
[Figure 3] and [Figure 4] represents photomicrograph of pancreas section of animals in Group A (control) showing even distribution of the pancreas Islet cells.Group B (diabetic induced) pancreas showing uneven distribution of pancreas islet cells and vacuolation of the central part of the pancreas islets occupied by β-cells. Group C (STZ-induced islet-cell destruction in rats treated with 250 mg/kg body weight of HU seeds extract) showing restored islet-cell cytoarchitecture similar to control. Group D (STZ-induced islet-cell destruction in rats treated with 250 mg/kg body weight of HU leaves) showing restored pancreatic islet-cell cytoarchitecture similar to control. Morphometric analysis is shown in [Figure 5]. There was significant (P < 0.05) reduction in whole nuclei of Pancreas Islet of animals in group B compared with control. Although whole nuclei in diabetic animals treated with Hunteria umbellate extracts (Groups C and D) showed significant (P < 0.05) reduction compared with control, there was significant (P < 0.05) increased compared with untreated diabetic animals (group B).
|Figure 3: Pancreatic Islet (369 × 348 pixels) RGB image on counter window of IMAGE J software showing (a) even distribution of the pancreas Islet cells in negatively induced control Group A (b) uneven distribution of fragmented Islet cells nuclei forming clumps (circle) of pancreatic islet cells of positively (streptozotocin [STZ]) induced control Group B (c) Pancreatic islet-cell in Group C (STZ-induced islet-cell destruction in rats treated with 250 mg/kg body weight of HU seeds extract) with almost even distribution similar to control group (d) Pancreatic Islet-cell in Group D (STZ-induced islet-cell destruction in rats treated with 250 mg/kg body weight of HU leaves extract) with sparsely distributed|
Click here to view
|Figure 4: Photomicrograph of pancreas section (a) negatively induced control Group A pancreas showing even distribution of the pancreas Islet cells (arrow). (b) positively (streptozotocin [STZ]) induced control Group B pancreas showing uneven distribution (clumps formed in localized areas marked on circle in photomiceograph) of pancreas islet cells (circle) and vacuolation of the central part of the pancreas islets occupied by -cells (arrow) (c) Group C (STZ-induced islet-cell destruction in rats treated with 250 mg/kg body weight of HU seeds extract) showing restored islet-cell cytoarchitecture similar to control (arrow) (d) Group D (STZ-induced islet-cell destruction in rats treated with 250 mg/kg body weight of HU leaves) showing restored pancreatic islet-cell cytoarchitecture similar to control (arrow) (H and E, ×400)|
Click here to view
|Figure 5: Bar chart showing the mean number of whole nuclei in 369 × 348 pixels pancreatic Islet RGB image on counter window of IMAGE J software. '*' and '#'represents significance of mean values when compared with control A and B respectively using Bonferroni multiple comparison test|
Click here to view
| Discussion|| |
Sterptozotocin is an antimicrobial agent originally derived from the soil micro-organism Streptomyces achromogenes (White, 1963; Herr et al., 1967; Weiss, 1982). It has been used as a chemotherapeutic alkylating agent in the treatment of metastasizing pancreatic islet cell tumors and in other malignancies (Evans et al., 1965; Schein et al., 1974). In 1963, Rakieten and collaborators reported that STZ is diabetogenic (Rakieten et al., 1963). Since then STZ has been used to induce experimental diabetes mellitus in laboratory animals (Rerup, 1970). This insulinopenia syndrome called "STZ diabetes" (Schein et al., 1967) is due to the ability of this compound to induce a specific necrosis of the pancreatic β-cells (Arison et al., 1967; Lenzen et al., 1996). The effect of HU extracts on the toxic action of STZ on pancreatic Islet-cells was the main focus of this research. The photomicrographs above shows that STZ induce Islet-cell necrosis by distorting cytoarchitectural arrangement of cells and reduce islet cell population [Figure 3] in group B rats and this effect was reversed in the photomicrographs C and D with almost same semblance as the control shown in [Figure 4]. This result was supported by the evaluated FBG concentration shown in [Figure 1]. Steptozotocin injected diabetic rats in Group B showed significant (P < 0.05) elevation of FBG. This result is indicative of pancreatic β-cell dysfunction that is accompanied by hypoinsulinemia and hence hyperglycemic (type 1-like diabetes mellitus). The FBG concentration of Group C rats (STZ injected rats treated with 250 mg/kg body weight of HU seed extract) was significantly (P < 0.05) reduced to considerably hypoglycemic range but 250 mg/kg body weight of HU leave extract given to STZ injected rats did not reduce the FBG concentration, but it was able to maintain it within fluctuating hyperglycemic ranges. This result corresponds with the findings of Adeyemi et al., 2009. Adeyemi et al. the hypoglycemic effect of lower doses of HU seed extracts (50-200 mg/kg) in normal and drug-induced hyperglycemia. Their result showed that seed extracts of HU caused progressive and significant (P < 0.05, 0.01 and 0.001) dose-related reduction of blood glucose concentration in both normal and drug-induced hyperglycemic rats. In a similar research carried out by Igbe et al., 2009, it was reported that 400 mg/kg body weight of seed extract of HU significantly (P < 0.05) reduced blood glucose concentration in diabetic rats.
The effects of STZ on glucose and insulin homeostasis reflect toxin-induced abnormalities in pancreatic β-cell function. The involvement of ROS in the toxic action of STZ, which may be produced during uric acid generation as the final product of ATP degradation by xanthine oxidase from hypoxanthine, has also been considered (Nukatsuka et al., 1990). And indeed, some evidence for a participation of ROS has been obtained in experiments with scavengers (Sandler and Swenne, 1983; Okamoto, 1996). Some minor generation of ROS including superoxide and hydroxyl radicals originating from hydrogen peroxide dismutation during hypoxanthine metabolism may accompany the effect of STZ and accelerate the process of β-cell destruction (Sandler and Swenne, 1983; Okamoto, 1996). Following the importance of ROS in pancreatic β- cell destruction occasioned by STZ, he antioxidant profile in serum and pancreas homogenates was analyzed. Results obtained indicates that SOD and CAT activities in serum and pancreas homogenates were significantly (P < 0.05) lower in Stretozotocin injected rats (positive induced control Group B) when compared with the nonstreptozotozin injected control rats (negative induced control A). Animals that were injected with STZ and treated with HU extracts (Groups C and D) showed significantly (P < 0.05) elevated SOD and CAT activities when compared with the STZ injected rats. Also, there was significant (P < 0.05) difference of lipid peroxidation in serum and pancreas homogenates of STZ injected rats (positive induced control Group B) when compared with negative control Group A rats while difference in lipid peroxidation was significantly lowered in the STZ injected rats treated extracts of HU. This suggests that there was increased levels of serum ROS in the strepotozotocin injected rats than the non-STZ injected rats. Increasing evidence in both experimental and clinical studies suggests that ROS plays a major role in the pathogenesis of diabetes mellitus (Maritim et al., 2003). Free radicals are formed disproportionately in diabetes by glucose oxidation, nonenzymatic glycation of proteins and the subsequent oxidative degradation of glycated proteins. In addition, the increase in oxygen free radicals (ROS) in diabetes could be primarily due to increase in blood glucose levels that upon auto-oxidation generate free radicals (Wolff and Dean, 1987). All these may have accounted for the decrease in serum levels of SOD, and CAT activity of the STZ injected Group B rats that was reversed on treatment with aqueous extracts of HU seeds and leaves. The decrease in the activities of SOD and CAT and an increase in TBARS in pancreas homogenate of STZ injected rats would be due to increase intracellular ROS, which has been reported to be the major contributor to DNA fragmentation and evoked deleterious changes in the pancreatic β-cells (Takasu et al., 1991; Bedoya et al., 1996), and hence the degenerative changes observed in the photomicrograph of pancreas of Group B rats [Figure 4]b. This effect on the pancreatic Islet cells was reversed on treatment with aqueous extracts of HU seeds and leaves as shown in Photomicrographs of Group C and D rats [Figure 4]. Thus, extracts of HU reversed the effect of STZ on antioxidant enzymes, FBG and pancreatic islet (β)-cell cytoarchitecture and population.
In conclusion, the extracts of HU possess antidiabetic, antioxidant and Islet cells regenerative potential.
| References|| |
Adeneye A.A., Adeyemi OO. (2009). Hypoglycaemic effect of aqueous seed extracts of Hunteria umbellata
in normoglycaemic and glucose and nicotine induced hyperglycaemic rats. Int J Appl Res Nat Prod 2 (1):9-18.
Adeneye A.A., Adeyemi O.O., Agbaje E.O. (2010). Anti-obesity and antihyperlipidaemic effect of Hunteria umbellata
seed extract in experimental hyperlipidaemia. J Ethnopharmacol 130 (2):307-14.
Adeneye A.A., Sofidiya M.O., Adenekan O.S. (2011). Anti-inflammatory and Antioxidant activities of Hunteria umbellata
seed Fractions. Pharmacologia 2:165-71.
Akbarzadeh A., Norouzian D., Mehrabi M.R., Jamshidi S.H., Farhangi A., Verdi A.A, et al.
(2007). Induction of diabetes by Streptozotocin in rats. Indian J Clin Biochem 22 (2):60-4.
Anibijuwon I., Abioye J.A., Onifade A.K. (2011). Comparative antimicrobial activities of some plant extracts and commercial antibiotics against some selected pathogens of food origin. Int J Med Med Sci 3 (8):268-72.
Arison R.N., Ciaccio E.I., Glitzer M.S., Cassaro J.A., Pruss M.P. (1967). Light and electron microscopy of lesions in rats rendered diabetic with streptozotocin. Diabetes 16 (1):51-6.
Bedoya F.J., Solano F., Lucas M. (1996). N-monomethyl-arginine and nicotinamide prevent streptozotocin-induced double strand DNA break formation in pancreatic rat islets. Experientia 52 (4):344-7.
Bennett R.A., Pegg A.E. (1981). Alkylation of DNA in rat tissues following administration of streptozotocin. Cancer Res 41 (7):2786-90.
Boone M.J. Hunteria umbellata
(K.schum). Hallier F. (2006). In: Schmelzer G.H., Gurib-Fakim A., editors. Prota II: Medicinal Plant/Plantes Medicinales (CD-Rom). PROTA, Wageningen, Netherlands.
Buege J.A., Aust S.D. (1978). Microsomal lipid peroxidation. In: Flesicher S, Packer L, editors. Methods in Enzymology. Vol. 52. Academic Press, New York, 302-10.
Cohen G., Dembiec D., Marcus J. (1970). Measurement of catalase activity in tissue extracts. Anal Biochem 34:30-8.
Delaney C.A, Dunger A., Di Matteo M., Cunningham J.M., Green M.H., Green I.C. (1995). Comparison of inhibition of glucose-stimulated insulin secretion in rat islets of Langerhans by streptozotocin and methyl and ethyl nitrosoureas and methanesulphonates. Lack of correlation with nitric oxide-releasing or O6-alkylating ability. Biochem Pharmacol 50 (12):2015-20.
Drury R.A., Wallington E.A. (1980). Carleton's Histological Technique. 5 th
ed. Oxford University Press, Oxford, 520-1.
Elsner M., Guldbakke B., Tiedge M., Munday R., Lenzen S. (2000). Relative importance of transport and alkylation for pancreatic beta-cell toxicity of streptozotocin. Diabetologia 43 (12):1528-33.
Elujoba A.A. (1995). Female infertility in the lands of traditional birth attendants in south western Nigeria. Fitoterapia 66:239-48.
Evans J.S., Gerritsen G.C., Mann K.M., Owen S.P. (1965). Antitumor and hyperglycemic activity of streptozotocin (NSC-37917) and its cofactor, U-15,774. Cancer Chemother Rep 48:1-6.
Falodun A., Nworgu Z.A., Ikponmwonsa M.O. (2006). Phytochemical components of Hunteria umbellata
(K. Schum) and its effect on isolated non-pregnant rat uterus in oestrus. Pak J Pharm Sci 19 (13):256-8.
Fridovich I. (1974). Superoxide dismutases. Adv Enzymol Relat Areas Mol Biol 41:35-97.
Herr RR, Jahnke JK, Argoudelis AD. (1967). The structure of streptozotocin. J Am Chem Soc 89 (18):4808-9.
Igbe I., Ozolua R.I., Okpo S.O., Obasuyi O. (2009). Antipyretic and analgesic effects of the aqueous extract of the fruit pulp of Hunteria umbellata
K. schum (Apocynaceae). Trop J Pharm Res 8 (4):331-6.
Kaey R.W., Onochie C.F., Stanfield D.P. (1989). Trees of Nigeria (formally Nigeria trees, 1960, 1964). Oxford University, Oxford, 234.
Kröncke K.D., Fehsel K., Sommer A., Rodriguez M.L., Kolb-Bachofen V. (1995). Nitric oxide generation during cellular metabolization of the diabetogenic N-methyl-N-nitroso-urea streptozotozin contributes to islet cell DNA damage. Biol Chem Hoppe Seyler 376 (3):179-85.
Lenzen S., Tiedge M., Jorns A., Munday R. (1996). Alloxan derivatives as a tool for the elucidation of the mechanism of the diabetogenic action of alloxan. In: Shafrir E., editor. Lessons from Animal Diabetes. Birkhauser, Boston, 113-22.
Miritam A.C., Sanders R.A., Watkins J.B. (2003). Pathogenesis of diabetes. J Biochem Mol Toxicol 17 (1):24-38.
Morgan N.G., Cable H.C., Newcombe N.R., Williams G.T. (1994). Treatment of cultured pancreatic B-cells with streptozotocin induces cell death by apoptosis. Biosci Rep 14 (5):243-50.
Nukatsuka M., Yoshimura Y., Nishida M., Kawada J. (1990). Allopurinol protects pancreatic beta cells from the cytotoxic effect of streptozotocin: In vitro
study. J Pharmacobiodyn 13 (4):259-62.
Nukatsuka M., Sakurai H., Yoshimura Y., Nishida M., Kawada J. (1998). Enhancement by streptozotocin of O2- radical generation by the xanthine oxidase system of pancreatic beta-cells. FEBS Lett 239 (2):295-8.
Nukatsuka M., Yoshimura Y., Nishida M., Kawada J. (1990). Importance of the concentration of ATP in rat pancreatic beta cells in the mechanism of streptozotocin-induced cytotoxicity. J Endocrinol 127 (1):161-5.
Okamoto H. (1996). Okamoto model for â-cell damage: Recent advances. In: Shafrir E, editor. Lessons from Animal Diabetes. Birkhauser, Boston, 97-111.
Oliver B. (1986). Medicinal Plants in Tropical West Africa. Cambridge University Press, Cambridge, 60-2.
Oluwemimo A., Usifoh C.O. (2001). The Antihelminthic activity of Hunteria umbellata
K. Schum.(Fam. Apocynaceae
) extract. Pak J Pharm Sci 44:286-90.
Rakieten N., Rakieten M.L., Nadkarni M.V. (1963). Studies on the diabetogenic action of streptozotocin (NSC-37917). Cancer Chemother Rep 29:91-8.
Rerup C.C. (1970). Drugs producing diabetes through damage of the insulin secreting cells. Pharmacol Rev 22 (4):485-518.
Sandler S., Swenne I. (1983). Streptozotocin, but not alloxan induces DNA repair synthesis in mouse pancreatic islets in vitro
. Daibetologia 25:444-7.
Schein P.S., O'Connell M.J., Blom J., Hubbard S., Magrath I.T., Bergevin P, et al.
(1974). Clinical antitumor activity and toxicity of streptozotocin (NSC-85998). Cancer 34 (4):993-1000.
Takasu N., Komiya I., Asawa T., Nagasawa Y., Yamada T. (1991). Streptozocin- and alloxan-induced H2O2 generation and DNA fragmentation in pancreatic islets. H 2
as mediator for DNA fragmentation. Diabetes 40 (9):1141-5.
Turk J., Corbett J.A., Ramanadham S., Bohrer A., McDaniel M.L. (1993). Biochemical evidence for nitric oxide formation from streptozotocin in isolated pancreatic islets. Biochem Biophys Res Commun 197 (3):1458-64.
Weiss R.B. (1982). Streptozocin: A review of its pharmacology, efficacy, and toxicity. Cancer Treat Rep 66 (3):427-38.
White F.R. (1963). Streptozotocin. Cancer Chemother Rep 30:49-53.
Wolf S.P., Dean R.T. (1987). Glucose auto-oxidation and protein modification. The potential role of auto-oxidative 'glycosylation' in diabetes. Biochem J 245:234-50.
Yamamoto H., Uchigata Y., Okamoto H. (1981). Streptozotocin and alloxan induce DNA strand breaks and poly (ADP-ribose) synthetase in pancreatic islets. Nature 294 (5838):284-6.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]