**3. Results**

#### **3.1. Phytochemical constituents of ethanolic extract of** *Acacia ataxacantha* **bark**

Table 1 shows the phytochemical constituents of ethanolic extract of *Acacia ataxacantha* bark. In the analysis carried out, alkaloids, polyphenols, flavonoids, saponins, tannins, terpernoids were present while glycoside was not detected.

#### **3.2. Glycemic effects of ethanolic extract of** *Acacia ataxacantha* **bark in streptozotocininduced diabetic rats**

Figure 3 presents the glycemic effects of ethanolic extract of *Acacia ataxacantha* bark in strep‐ tozotocin-induced diabetic rats. There was continuous increase in the fasting blood glucose level of diabetic control rats from the first day of treatment till the sixth day. While, upon oral administration of ethanolic extract of *Acacia ataxacantha* bark, there was a significant reduction (p<0.05) in the fasting blood glucose level, of rats administered 125 mg/kg body weight of the extract, decline in the fasting blood glucose concentration began on day 3 and continued till day 6. Whereas, continuous reduction was recorded for fasting blood glucose concentration from day 2 upon oral administration of 250 mg/kg and 500 mg/kg body weight of the extract and standard drug (metformin).

**Figure 3.** Effects of ethanolic extract of *Acacia ataxacantha* bark on the fasting blood level of STZ-induced diabetic rats

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Values are means (n=6) ± S.D (bars with different superscripts are significantly different at p<0.05).

diabetic rats

**Figure 4.** Effects of ethanolic extract of *Acacia ataxacantha* bark on the hepatic glucose concentration of STZ-induced

#### **3.3. Effects of ethanolic extract of** *Acacia ataxacantha* **bark on hepatic glucose and glycogen concentration**

Figures 4 and 5 depict the effects of ethanolic extract of *Acacia ataxacantha* bark on the hepatic glucose and glycogen levels of STZ – induced diabetic rats. There was a significant difference (p>0.05) in the hepatic glucose and glycogen levels in all the treatment groups compared to the normal control. However, highest hepatic glucose and least glycogen concentrations were recorded in the diabetic control when compared to the control.


Keys: Presence of constituents (+); Absence of constituents (-)

**Table 1.** Phytochemical screening of ethanolic extract of *Acacia ataxacantha* bark

variance (ANOVA), followed by Dunett's posthoc test for multiple comparism. Values were

Table 1 shows the phytochemical constituents of ethanolic extract of *Acacia ataxacantha* bark. In the analysis carried out, alkaloids, polyphenols, flavonoids, saponins, tannins, terpernoids

**3.2. Glycemic effects of ethanolic extract of** *Acacia ataxacantha* **bark in streptozotocin-**

Figure 3 presents the glycemic effects of ethanolic extract of *Acacia ataxacantha* bark in strep‐ tozotocin-induced diabetic rats. There was continuous increase in the fasting blood glucose level of diabetic control rats from the first day of treatment till the sixth day. While, upon oral administration of ethanolic extract of *Acacia ataxacantha* bark, there was a significant reduction (p<0.05) in the fasting blood glucose level, of rats administered 125 mg/kg body weight of the extract, decline in the fasting blood glucose concentration began on day 3 and continued till day 6. Whereas, continuous reduction was recorded for fasting blood glucose concentration from day 2 upon oral administration of 250 mg/kg and 500 mg/kg body weight of the extract

**3.3. Effects of ethanolic extract of** *Acacia ataxacantha* **bark on hepatic glucose and glycogen**

Figures 4 and 5 depict the effects of ethanolic extract of *Acacia ataxacantha* bark on the hepatic glucose and glycogen levels of STZ – induced diabetic rats. There was a significant difference (p>0.05) in the hepatic glucose and glycogen levels in all the treatment groups compared to the normal control. However, highest hepatic glucose and least glycogen concentrations were

> + + + + \_ + +

Keys: Presence of constituents (+); Absence of constituents (-)

recorded in the diabetic control when compared to the control.

**Table 1.** Phytochemical screening of ethanolic extract of *Acacia ataxacantha* bark

Alkaloids Polyphenols Flavonoids Saponin Glycoside Tannins Terpenoid

Phytochemicals Extract

**3.1. Phytochemical constituents of ethanolic extract of** *Acacia ataxacantha* **bark**

considered statistically significant at p<0.05 (confidence level = 95%).

were present while glycoside was not detected.

8 Antioxidant-Antidiabetic Agents and Human Health

**3. Results**

**induced diabetic rats**

and standard drug (metformin).

**concentration**

**Figure 3.** Effects of ethanolic extract of *Acacia ataxacantha* bark on the fasting blood level of STZ-induced diabetic rats

Values are means (n=6) ± S.D (bars with different superscripts are significantly different at p<0.05).

**Figure 4.** Effects of ethanolic extract of *Acacia ataxacantha* bark on the hepatic glucose concentration of STZ-induced diabetic rats

**Parameters Control Diabetic control 125mg/kg 250mg/kg 500mg/kg Metformin**

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Urea 29.67±0.3a 40.23±0.10c 23.49±1.19b 29.82±0.59a 21.04±1.22b 30.29±0.5a

Creatinine 0.47±0.14a 0.57±0.12b 0.48±0.15a 0.48±0.01a 0.50±0.13a 0.49±0.10a

Albumin 18.67±0.33a 27.01±0.61c 22.00±1.15b 21.33±0.33c 25.33±0.88c 20.00±1.2ab

**Table 2.** Effects of ethanolic extract of *Acacia ataxacantha* bark on the concentration of some serum parameters of

Values are means (n=6) ± S.D (bars with different superscripts are significantly different at p<0.05).

ethanolic extract of *Acacia ataxacantha* bark and metformin.

**Figure 6.** Effects of ethanolic extract of *Acacia ataxacantha* bark on the serum lipid profile of STZ-induced diabetic rats

Figure 7 shows the effect of administration of ethanolic extract of *Acacia ataxacantha* bark on the total bilirubin and conjugated bilirubin level in streptozotocin induced diabetic rats. Both total biliribin and conjugated bilirubin were significantly higher (p<0.05) in diabetic untreated compared to the control, but it was significantly decreased (p<0.05) upon administration of

Values are expressed as mean of six determinations ± SEM

STZ-induced diabetic rats

Row values with different superscripts are significantly (p<0.05) different

Values are means (n=6) ± S.D (bars with different superscripts are significantly different at p<0.05).

**Figure 5.** Effects of ethanolic extract of *Acacia ataxacantha* bark on the hepatic glycogen concentration of STZ-in‐ duced diabetic rats

#### **3.4. Effect of administration of ethanolic extract of** *Acacia ataxacantha* **bark on serum parameters of streptozotocin-induced diabetic rats**

The influence of administration of ethanolic extract of *Acacia ataxacantha* bark on serum parameters is shown in Table 2. There was a significant difference (p<0.05) in the urea level in all the treatment groups when compared to the control except that 250 mg/kg body weight and metformin displayed a similar pattern to the control. Also, there was no significant difference (p>0.05) in the creatinine level in all the treatment groups when compared to the control but a significant increase (p<0.05) was observed in diabetic control compared to the normal control. There were significant differences (p<0.05) in albumin level of all groups compared to the control except that 250 mg/kg b.w and metformin were similar in pattern to the control.

#### **3.5. Effect of administration of ethanolic extract of** *Acacia ataxacantha* **bark on the lipids profile of streptozotocin-induced diabetic rats**

Figure 6 shows the effect of ethanolic extract of *Acacia ataxacantha* bark on serum total choles‐ terol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C) and triglyceride. The serum total cholesterol (TC), low density lipoprotein cholesterol (LDL-C) and triglyceride concentrations were significantly reduced (p<0.05) upon adminis‐ tration of ethanolic extract of *Acacia ataxacantha* bark and metformin.


Values are expressed as mean of six determinations ± SEM

Values are means (n=6) ± S.D (bars with different superscripts are significantly different at p<0.05).

**parameters of streptozotocin-induced diabetic rats**

10 Antioxidant-Antidiabetic Agents and Human Health

**profile of streptozotocin-induced diabetic rats**

tration of ethanolic extract of *Acacia ataxacantha* bark and metformin.

duced diabetic rats

the control.

**Figure 5.** Effects of ethanolic extract of *Acacia ataxacantha* bark on the hepatic glycogen concentration of STZ-in‐

The influence of administration of ethanolic extract of *Acacia ataxacantha* bark on serum parameters is shown in Table 2. There was a significant difference (p<0.05) in the urea level in all the treatment groups when compared to the control except that 250 mg/kg body weight and metformin displayed a similar pattern to the control. Also, there was no significant difference (p>0.05) in the creatinine level in all the treatment groups when compared to the control but a significant increase (p<0.05) was observed in diabetic control compared to the normal control. There were significant differences (p<0.05) in albumin level of all groups compared to the control except that 250 mg/kg b.w and metformin were similar in pattern to

**3.5. Effect of administration of ethanolic extract of** *Acacia ataxacantha* **bark on the lipids**

Figure 6 shows the effect of ethanolic extract of *Acacia ataxacantha* bark on serum total choles‐ terol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C) and triglyceride. The serum total cholesterol (TC), low density lipoprotein cholesterol (LDL-C) and triglyceride concentrations were significantly reduced (p<0.05) upon adminis‐

**3.4. Effect of administration of ethanolic extract of** *Acacia ataxacantha* **bark on serum**

Row values with different superscripts are significantly (p<0.05) different

**Table 2.** Effects of ethanolic extract of *Acacia ataxacantha* bark on the concentration of some serum parameters of STZ-induced diabetic rats

Values are means (n=6) ± S.D (bars with different superscripts are significantly different at p<0.05).

**Figure 6.** Effects of ethanolic extract of *Acacia ataxacantha* bark on the serum lipid profile of STZ-induced diabetic rats

Figure 7 shows the effect of administration of ethanolic extract of *Acacia ataxacantha* bark on the total bilirubin and conjugated bilirubin level in streptozotocin induced diabetic rats. Both total biliribin and conjugated bilirubin were significantly higher (p<0.05) in diabetic untreated compared to the control, but it was significantly decreased (p<0.05) upon administration of ethanolic extract of *Acacia ataxacantha* bark and metformin.

#### **3.6. Effect of the administration of ethanolic extract of** *Acacia ataxacantha* **bark on aspartate and alanine aminotransferase activities in streptozotocin induced diabetic rats**

**Parameters Control**

**Parameters Control**

**Diabetic**

Row values with different superscripts are significantly (p<0.05) different

**Diabetic**

Row values with different superscripts are significantly (p<0.05) different.

Values are expressed as mean of six determinations ± SEM

Values are expressed as mean of six determinations ± SEM

activity in streptozotocin-induced diabetic rats

activities in streptozotocin-induced diabetic rats

Liver 0.48±0.00a 0.14±0.00b 0.45±0.01a 0.46±0.00a 0.14±0.00b 0.57±0.00a Serum 0.15±0.01a 0.46±0.00c 0.43±0.22b 0.17±0.00a 0.26±0.00b 0.15±0.20a

**Table 3.** Effect of the administration of ethanolic extract of *Acacia ataxacantha* bark on the alanine aminotransferase

Liver 0.36±0.03a 0.14±0.00b 0.68±0.00c 0.67±0.01c 0.13±0.02b 0.65±0.01c Serum 0.24±0.08a 0.72±0.01d 0.48±0.00b 0.62±0.00c 0.60±0.01c 0.52±0.01b

**Table 4.** Effect of the administration of ethanolic extract of *Acacia ataxacantha* bark on aspartate aminotransferase

Values are means (n=6) ± S.D (bars with different superscripts are significantly different at p<0.05)

**Figure 8.** Effects of ethanolic extract of *Acacia ataxacantha* bark on the lipid peroxidation in STZ-induced diabetic rats

**control 125mg/kg 250mg/kg 500mg/kg Metformin**

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**control 125mg/kg 250mg/kg 500mg/kg Metformin**

Tables 3 and 4 show the effect of administration of ethanolic extract of *Acacia ataxacantha* bark on alanine and aspartate aminotransferase activities in the liver and serum respectively. There was a significant reduction (p<0.05) in the activity of ALT in the groups administered 500mg/ kg b.w when compared to the control while there was no significant difference in the remaining treatment groups. However, in the serum, there was no significant difference (p>0.05) in ALT activity except in the groups administered 500mg/kg b.w and metformin when compared to the normal control. There were significant alterations (p<0.05) in the activity of AST in the liver of all the groups compared to the normal control. However, significant elevations (p<0.05) were observed in the activity of AST in the serum of all treatment groups when compared to the control.

#### **3.7. Effects of ethanolic extract of** *Acacia ataxacantha* **bark on pancreatic lipid peroxidation of streptozotocin-induced diabetic rats**

Figure 8 depicts the effects of ethanolic extract of *Acacia ataxacantha* bark on the pancreatic lipid peroxidation in STZ - induced diabetic rats. There were no significant differences (p>0.05) in malondialdehyde concentration in the pancreas of rats administered 125mg/kg body weight and metformin when compared to the control. However, there was a significant elevation (p<0.05) in the concentration of thiobarbituric acid (TBA) reacting substance in the pancreas of rats administered 250 mg/kg b.w, 500 mg/kg b.w and diabetic but not treated rats when compared to the normal control.

Values are means (n=6) ± S.D (bars with different superscripts are significantly different at p<0.05).


Values are expressed as mean of six determinations ± SEM

**3.6. Effect of the administration of ethanolic extract of** *Acacia ataxacantha* **bark on aspartate**

Tables 3 and 4 show the effect of administration of ethanolic extract of *Acacia ataxacantha* bark on alanine and aspartate aminotransferase activities in the liver and serum respectively. There was a significant reduction (p<0.05) in the activity of ALT in the groups administered 500mg/ kg b.w when compared to the control while there was no significant difference in the remaining treatment groups. However, in the serum, there was no significant difference (p>0.05) in ALT activity except in the groups administered 500mg/kg b.w and metformin when compared to the normal control. There were significant alterations (p<0.05) in the activity of AST in the liver of all the groups compared to the normal control. However, significant elevations (p<0.05) were observed in the activity of AST in the serum of all treatment groups when compared to

**3.7. Effects of ethanolic extract of** *Acacia ataxacantha* **bark on pancreatic lipid peroxidation**

Figure 8 depicts the effects of ethanolic extract of *Acacia ataxacantha* bark on the pancreatic lipid peroxidation in STZ - induced diabetic rats. There were no significant differences (p>0.05) in malondialdehyde concentration in the pancreas of rats administered 125mg/kg body weight and metformin when compared to the control. However, there was a significant elevation (p<0.05) in the concentration of thiobarbituric acid (TBA) reacting substance in the pancreas of rats administered 250 mg/kg b.w, 500 mg/kg b.w and diabetic but not treated rats when

Values are means (n=6) ± S.D (bars with different superscripts are significantly different at p<0.05).

**Figure 7.** Effects of ethanolic extract of *Acacia ataxacantha* bark on the bilirubin levels of STZ-induced diabetic rats

**and alanine aminotransferase activities in streptozotocin induced diabetic rats**

the control.

**of streptozotocin-induced diabetic rats**

12 Antioxidant-Antidiabetic Agents and Human Health

compared to the normal control.

Row values with different superscripts are significantly (p<0.05) different

**Table 3.** Effect of the administration of ethanolic extract of *Acacia ataxacantha* bark on the alanine aminotransferase activities in streptozotocin-induced diabetic rats


Values are expressed as mean of six determinations ± SEM

Row values with different superscripts are significantly (p<0.05) different.

**Table 4.** Effect of the administration of ethanolic extract of *Acacia ataxacantha* bark on aspartate aminotransferase activity in streptozotocin-induced diabetic rats

Values are means (n=6) ± S.D (bars with different superscripts are significantly different at p<0.05)

**Figure 8.** Effects of ethanolic extract of *Acacia ataxacantha* bark on the lipid peroxidation in STZ-induced diabetic rats

#### **3.8. Effects of ethanolic extract of** *Acacia ataxacantha* **bark on pancreatic superoxide dismutase activities of streptozotocin-induced diabetic rats**

Figure 9 shows the effects of ethanolic extract of *Acacia ataxacantha* bark on the activity of pancreatic superoxide dismutase. There were significant alterations (p<0.05) in the superoxide dismutase activity in the pancreas of all the tretment groups except the groups administered 500 mg/kg b.w of the extract and metformin, which compared favourably with the control.

hypoglyceamic activity and medicinal value. These compounds have been shown to be responsible for hypoglyceamic activity in *Momordica charantia* [37]. The activities of flavonoids and polyphenol have been ascribed to the structural relationship between different parts of

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STZ is a broad spectrum antibiotic extracted from *Streptomyces acromogenes*. The STZ-induced diabetes causes the destruction of pancreatic β cells of islets, which leads to a reduction of insulin release and increase in blood glucose. STZ – induced diabetes has been described as a useful experimental model to study the antidiabetic activity of several agents [39]. STZ is well known for its selective pancreatic islet β-cell cytotoxicity used to induce diabetes mellitus in animals. It interferes with cellular metabolic oxidative mechanisms [39]. Significant elevation was observed in fasting blood glucose in diabetic rats. This observed hyperglycemia may be due to induced gluconeogenesis in the absence of insulin [40]. However, marked reductions observed after 2 days and the progressive decrease till the 6th day which was highest in 125 mg/kg and 250 mg/kg b.w of the extract compared well with the standard drug (metformin). These decreases could be due to the direct stimulation of the secretion of insulin thus promot‐ ing glucose uptake metabolism by inhibiting hepatic gluconeogenesis through the stimulation

The increased levels of hepatic glucose in streptozotocin - induced diabetic rats were reduced following the administration of ethanolic extract of *Acacia ataxacantha* bark. The reduced glucose levels suggests that ethanolic extract of *Acacia ataxacantha* bark may have exerted insulin-like effect on peripheral tissues by either promoting glucose uptake metabolism by inhibiting hepatic gluconeogenesis [42] or by absorption of glucose into the muscle and adipose tissues [43] through the stimulation of a regeneration process and revitalization of the

Glycogen is the primary intracellular storable form of glucose in various tissues and its level in such tissues especially the liver is a direct reflection of insulin activity [44]. The glycogen content was decreased in the liver of diabetic rats in this study. But upon oral administration of ethanolic extract of *Acacia ataxacantha* bark, glycogen content were increased significantly which is comparable to that of metformin, thus confirming its insulin potentiating action to a marked extent. This may be due to the activation of glycogen synthase system and inhibition of glycogen phosphorylase [45] by the extract. It may also be due to decreased enzymatic activities of hexokinase and phosphofructokinase resulting in depletion of liver and muscle

The concentrations of total protein, bilirubin and albumin may indicate state of the liver and type of damage [47]. Bilirubin is formed by the breakdown of hemoglobin in the liver, spleen and bone marrow [48]. An increase in tissue or serum albumin concentrations results in jaundice. Jaundice occurs in toxic or infectious diseases of the liver [49]. The significant increase in the total bilirubin, conjugated bilirubin and albumin levels in the diabetic control rats and reduction following oral administration of ethanolic extract of *Acacia ataxacantha* bark are

indicative of amelioration of the adverse effects caused by diabetes.

of a regeneration process and revitalization of the remaining beta cells [41].

their chemical structures [38].

remaining beta cells [42,43].

glycogen [46].

Values are means (n=6) ± S.D (bars with different superscripts are significantly different at p<0.05).

**Figure 9.** Effects of ethanolic extract of *Acacia ataxacantha* bark on the superoxide dismutase activity of STZ-induced diabetic rats
