**5. Results and discussion**

Phytochemical screening of the leaves of *P. amarus* showed the presence of alkaloids, tannin, flavonoids, saponin, anthraquinones and cardiac glycosides. Flavonoids and tannins are phenolic compounds and plant phenolics are also a major group of compounds that act as primary antioxidants or free radical scavengers (Adedapo et al., 2008a, 2008b, Ayoola et al., 2008). Tannins and saponins are also found to be effective antioxidants, antimicrobial, and anti-carcinogenic agents (Lai et al., 2010). Polyphenolic compounds are ubiquitous in foods of plant origin, and thus they constitute an integral part of the human diet (Bravo 1998). In‐ terest in polyphenols has greatly increased recently because these phytochemicals are known to suppress rates of degenerative processes such as cardiovascular disorders and cancer (Bravo 1998, Duthie 2000, Huang et al., 2007; Jimoh et al., 2010). Some of these poten‐ tial health benefits of polyphenolic substances have been related to the action of these com‐ pounds as antioxidants, free radical scavengers, quenchers of singlet and triplet oxygen and inhibitors of peroxidation (Li-Chen et al., 2005). As a group, phenolic compounds have been found to be strong antioxidants against free radicals and other reactive oxygen species, the major cause of many chronic human diseases (Kyung-Hee et al., 2005, Chen and Yen 2007).

In the acute toxicity test, no death was recorded in all the groups. All the mice appeared to be normal and none of them showed any visible signs of toxicity. Acute oral administration of *Phyllanthus amarus* to mice indicated that the plant is non toxic even at the dose of 1600mg/kg body weight. It thus showed that this plant is safe for medicinal use at this dose.

The aqueous extract caused a significant (P<0.05) dose related reduction in the fasting blood glucose (FBG) of normoglycaemic rats. Maximum reduction occurred within 2hr post- treat‐ ment with 400mg/kg dose of the extract (Table 1). In this study, experimental evaluation of the antidiabetic potentials of *P*. *amarus* has shown that single oral administration of the ex‐ tract to normal rats reduced fasting blood glucose which suggests an inherent hypoglycae‐ mic effect (Table 2). The extract also suppressed the postprandial rise in blood glucose in normal rats following a heavy glucose meal with maximum suppressive effect coinciding with the time of peak blood glucose level after the meal (Table 3). Chronic hyperglycaemia in DM is a risk factor constantly fuelled by postprandial elevation of blood glucose. Control of postprandial hyperglycaemia in diabetes is of great importance due to its close relation to the risk of micro and macro-vascular complications and death (Balkau, 2000; Ceriello, 2005).


Following oral administration of glucose, postprandial blood glucose levels of the control rats increased to the peak at 60min. Pre-treatment with aqueous extract (200 and 400mg/kg) suppressed the rise in blood glucose by 28.1 and 8.1% respectively. The aqueous extract used in this study evoked a progressive dose-dependent decrease in blood glucose level up to 180mins. Chronic oral administration of aqueous extract caused a significant (P<0.05) dose-related reduction in blood glucose of diabetic rats. The extract at dose of 400mg/kg re‐ duced the blood glucose of the treated rats better than glibenclamide; while the extract at 200mg/kg exerts almost the same effect as glibenclamide. The highest reduction in the blood glucose was 60.9% and this was obtained with the 400mg/kg on 28th day (Table 4). In this study, daily oral administration of the extract for 28 days produced a gradual but sustained reduction in blood glucose levels in diabetic rats. Alloxan causes hyperglycaemia and glu‐ cose intolerance or syndromes similar to either type 1 or type 2 DM (Lenzen et al., 1996: Frode and Medeiros, 2008). Effective and sustained reduction in blood glucose levels of treated diabetic rats by the extract indicates that the plant may be useful in overt cases of DM. Effective control of blood glucose level is a key step in preventing and reversing diabet‐ ic complications, and improving the quality of life of diabetic patients (Bavarva and Nara‐

The Antidiabetic Activities of the Aqueous Leaf Extract of Phyllanthus Amarus in some Laboratory Animals

**Blood glucose concentration (mg/dl**)

**Diabetic Post-Rx Day 14 Day 28**

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123

122.0±9.3a (57.9)

126±19.9a (57.4)

107.8±5.0a (60.9)

) indicate significant values when

(49.0)

(52.7)

(52.2)

**Diabetic (Pretreatment)**

2ml/kg 57.4±6.2 58.8±5.8 69.2±4.6a 86.6±4.6a

200 54.8±8.4 56.8±8.7 70.8±7.4a 90.2±5.5a

simhacharya, 2008).

Control (NDNT)

Control (NDT)

a

ues.

**Treatment Dose**

**mg/kg**

**Pre-Diabetic (Basal)**

Glibenclamide 0.2 56.2±5.2 290±26.1 148.0±13.3a

Aqueous Extract 200 55.0±5.0 296.0±32.3 140.0±20.7a

Aqueous Extract 400 53.4±3.3 276.0±24.2 132.0±17.2a

**Table 4.** Effect of Aqueous extract of *P. amarus* on blood glucose of diabetic rats (n=5; mean ± SD.)

compared to diabetic pre-treatment values. NDNT= Non-diabetic non-treated was a non-diabetic control and received the vehicle; NDT= Non-diabetic treated was a non-diabetic control and received AE (200mg/kg). Values in parenthesis represent reduction (%) in blood glucose level calculated for treatment groups relative to diabetic pre-treatment val‐

P< 0.05 compared to diabetic pre-treatment values (t-Test). Superscripted items (a

abP< 0.05 compared to control and pre-treatment values respectively (t-test). Values in parenthesis represent reduction (%) in fasting blood levels glucose levels of normoglycaemic rats calculated relative to pre-treatment values.

**Table 1.** Effects of Aqueous extract of *P. amarus* on blood glucose of normoglycaemic rats (n=5; mean ± SD.).


a P< 0.05 compared to 0 minute values (t-Test). Superscripted items (a ) indicate significant values when compared to 0 min values. Values in parenthesis represent change (%) in blood glucose level calculated relative to 0 min.

**Table 2.** Effects of aqueous extract of *Phyllanthus amarus* on oral glucose tolerance in rats (n=5; mean ± SD.)


abP< 0.05 compared to control and pre-treatment values respectively (t-Test). Superscripted items (ab) indicate signifi‐ cant values when compared to control and pre-treatment values respectively. Values in parenthesis represent reduc‐ tion (%) in blood glucose level calculated relative to pre treatment values.

**Table 3.** Hypoglycaemic effects of aqueous extract of *P. amarus* on diabetic rats (n=5; mean ± SD.)

Following oral administration of glucose, postprandial blood glucose levels of the control rats increased to the peak at 60min. Pre-treatment with aqueous extract (200 and 400mg/kg) suppressed the rise in blood glucose by 28.1 and 8.1% respectively. The aqueous extract used in this study evoked a progressive dose-dependent decrease in blood glucose level up to 180mins. Chronic oral administration of aqueous extract caused a significant (P<0.05) dose-related reduction in blood glucose of diabetic rats. The extract at dose of 400mg/kg re‐ duced the blood glucose of the treated rats better than glibenclamide; while the extract at 200mg/kg exerts almost the same effect as glibenclamide. The highest reduction in the blood glucose was 60.9% and this was obtained with the 400mg/kg on 28th day (Table 4). In this study, daily oral administration of the extract for 28 days produced a gradual but sustained reduction in blood glucose levels in diabetic rats. Alloxan causes hyperglycaemia and glu‐ cose intolerance or syndromes similar to either type 1 or type 2 DM (Lenzen et al., 1996: Frode and Medeiros, 2008). Effective and sustained reduction in blood glucose levels of treated diabetic rats by the extract indicates that the plant may be useful in overt cases of DM. Effective control of blood glucose level is a key step in preventing and reversing diabet‐ ic complications, and improving the quality of life of diabetic patients (Bavarva and Nara‐ simhacharya, 2008).

**Treatment Dose**

**Treatment Dose**

**mg/kg**

**Glibenclamide** 0.2 65.0±2.8 67.8±2.7

**Aqueous Extract** 400 62.0±9.0 65.4±6.2

**mg/kg**

**Glibenclamide** 0.2 290.0±26.1 268.0±27.7

tion (%) in blood glucose level calculated relative to pre treatment values.

**Treatment Dose**

**Control** 2ml/kg 61.4±1.9 74.4±4.6

Aqueous Extract

Aqueous Extract

Aqueous Extract

Aqueous Extract

a

**mg/kg**

122 Antioxidant-Antidiabetic Agents and Human Health

**Glibenclamide** 0.2 72.2±4.1 66.6±3.4b

200 73.0±4.0 69.6±4.0

(21.2)

(4.3)

(16.9)

(5.5)

200 296.0±39.3 276.0±32.2

400 276.0±24.2 256.0±20.6a

**Table 3.** Hypoglycaemic effects of aqueous extract of *P. amarus* on diabetic rats (n=5; mean ± SD.)

min values. Values in parenthesis represent change (%) in blood glucose level calculated relative to 0 min.

**Table 2.** Effects of aqueous extract of *Phyllanthus amarus* on oral glucose tolerance in rats (n=5; mean ± SD.)

**Control** 2ml/kg 311.0±33.8 298.0±34.3 282.0±31.2 268.0±24.8 256.0±24.2

(7.6)

(6.8)

(7.3)

abP< 0.05 compared to control and pre-treatment values respectively (t-Test). Superscripted items (ab) indicate signifi‐ cant values when compared to control and pre-treatment values respectively. Values in parenthesis represent reduc‐

200 62.6±6.7 73.2±7.5a

P< 0.05 compared to 0 minute values (t-Test). Superscripted items (a

**Fasting Blood Glucose level (mg/dl) Pretreatment 0.5hr 1hr 2hr 4hr**

> 62.0±6.9b (14.1)

> 64.0±4.2b (12.3)

**0 min 30min 60min 90min 120min 150min 180min**

73.2±5.8 (19.2)

66.8±4.1 (2.8)

72.8±4.5a (16.3)

63.4±4.7 (2.3)

**Blood Glucose level (mg/dl) Pretreatment 0.5hr 1hr 2hr 4hr**

> 252.0±27.1 (13.1)

> 256.0±35.1 (13.5)

236.0±20.6ab (14.5)

69.8±5.5 (13.7)

64.2±7.8(1. 2)

> 64.2±3.5 (2.6)

> 59.6±3.8 (3.9)

54.0±3.4ab (25.2)

56.0±4.9ab (23.3)

> 63.2±7.1 (2.9)

62.4±1.5(4. 00)

> 55.4±5.8 (11.5)

> 54.0±2.3 (12.9)

) indicate significant values when compared to 0

228.0±17.2ab (21.4)

230.0±36.9b (22.3)

217.0±24.4ab (21.4)

49.0±3.9 ab (32.1)

50.6±5.8ab (30.7)

59.6±5.1 (2.9)

61.8±1.8(4.9)

49.4±4.6a (21.1)

50.6±2.2a (12.4)

208.0±16.3ab (28.3)

204.0±43.1ab (31.1)

200.0±18.7ab (27.5)

**Control** 2ml/kg 72.4±5.5 71.2±6.0 70.6±5.6 70±5.1 70±4.7

(7.7)

(4.7)

abP< 0.05 compared to control and pre-treatment values respectively (t-test). Values in parenthesis represent reduction

**Blood Glucose level (mg/dl)**

78.0±7.0 (27.0)

70.2±4.0a (8.00)

80.2±6.7a (28.1)

67.0±5.4 (8.1)

(%) in fasting blood levels glucose levels of normoglycaemic rats calculated relative to pre-treatment values.

**Table 1.** Effects of Aqueous extract of *P. amarus* on blood glucose of normoglycaemic rats (n=5; mean ± SD.).


a P< 0.05 compared to diabetic pre-treatment values (t-Test). Superscripted items (a ) indicate significant values when compared to diabetic pre-treatment values. NDNT= Non-diabetic non-treated was a non-diabetic control and received the vehicle; NDT= Non-diabetic treated was a non-diabetic control and received AE (200mg/kg). Values in parenthesis represent reduction (%) in blood glucose level calculated for treatment groups relative to diabetic pre-treatment val‐ ues.

**Table 4.** Effect of Aqueous extract of *P. amarus* on blood glucose of diabetic rats (n=5; mean ± SD.)


Ahmed et al., 2001; Okoli et al., 2010) and mimics overt diabetes disease. Thus, in addition to glycaemic control, extract of this plant may further reduce mortality from complications of the disease by ameliorating diabetes-induced dislipidaemia. The RBC count of all the ani‐ mals was reduced on day 14 with all the groups showing significant difference except the 400mg/kg dose of the aqueous extract. Subsequently, there was increase in the RBC count on day 28 with all the groups showing significant difference with the exception of the 400mg/kg dose of the aqueous extract. The white blood cell (WBC) count of all the control and glibenclamide- treated animals was reduced initially on day 14 with no significant dif‐ ference; while there was increase in the WBC count of the extract-treated group on day 14 and the increase continued on day 28 with the 400mg/kg dose of the extract showing signifi‐ cant difference. Likewise, there was subsequent increase in the control (both NDT and NDNT) groups and glibenclamide-treated group on day 28 with no significant difference (Table 6). Again, assessment of the effect of chronic administration of the extracts on haemo‐ globin level as well as white blood cell and red blood cell counts revealed an increase fol‐ lowing an initial reduction in most cases of the experiment. It is not clear if it would

The Antidiabetic Activities of the Aqueous Leaf Extract of Phyllanthus Amarus in some Laboratory Animals

**Parameters RBC (X106/µL); WBC (X103/µL)**

**Diabetic (Pre-Rx)**

4.9±0.1 4.8±0.3

5.1±0.03 4.9±0.3

5.3±0.3 5.0±0.5

5.1±0.1 4.8±0.3

4.6±0.3 4.8±0.2

**Diabetic Post-Rx Day 14 Day 28**

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125

6.8±0.7ab 4.9±0.3

5.0±0.2a 5.1±0.03

5.4±0.2 4.8±0.1

5.4±0.1ab 5.1±0.3

4.8±0.1 5.2±0.1ab

4.6±0.1ab 4.8±0.3

4.9±0.1ab 4.8±0.3

4.8±0.3ab 4.7±0.2

4.8±0.2ab 5.0±0.3

> 4.6±0.1 5.0±0.1

**PreDiabetic (Basal)**

> 5.2±0.1 4.8±0.3

> 5.2±0.1 5.0±0.3

> 5.6±0.2 4.7±0.6

> 5.2±0.1 4.8±0.3

> 4.8±0.4 4.9±0.2

abP<0.05 compared to Basal and Diabetic pre-treatment values respectively (t-Test); Superscripted items (ab) indicate significant values when compared to control and pre-treatment values respectively. NDT = Non diabetic treated was a non diabetic control and received aqueous extract (200mg/kg); NDNT = Non diabetic non treated was a non diabetic

**Table 6.** Effect of Aqueous extract of *P. amarus* on the Red Blood Cell (RBC) and White Blood Cell (WBC) counts of

There was increase in the body weight of all the groups on day 14 and the increase contin‐ ued on day 28 with the 400mg/kg dose of aqueous extract showing significant difference (P<0.05). The weight increase occurred most in the NDT control group followed by the NDNT control group and then the 400mg/kg dose of aqueous extract (Table 7). Due to the association of obesity with DM, weight control is an important aspect of diabetes manage‐

progress to a return to basal levels and how long it may take.

**Treatment Dose**

Glibenclamide 0.2 RBC

Aqueous Extract 200 RBC

Aqueous Extract 400 RBC

control and received the vehicle.

diabetic rats (n=5; mean ± SD.)

Control (NDNT)

Control (NDT)

**mg/kg**

2ml/kg RBC

200 RBC

WBC

WBC

WBC

WBC

WBC

abP<0.05 compared to Basal and Diabetic pre-treatment values respectively (t-Test); Superscripted items (ab) indicate significant values when compared to control and pre-treatment values respectively. NDNT=Non diabetic non treated was a non diabetic control and received the vehicle, NDT = Non diabetic treated was a non diabetic control and re‐ ceived aqueous extract (200mg/kg). Values in parenthesis represent reduction (%) of total cholesterol and triglycer‐ ides calculated for treatment groups relative to diabetic pre-treatment values.

**Table 5.** Effect of Aqueous extract of *P. amarus* on Cholesterol, triglycerides and haemoglobin levels of diabetic rats (n=5; mean ± SD.)

Chronic administration of aqueous extract reduced total cholesterol level of diabetic rats. The aqueous extract caused a significant (P<0.05) reduction in the total cholesterol of treated diabetic rats. The magnitude of reduction was greater than that evoked by glibenclamide. Chronic administration of aqueous extract reduced triglyceride concentration of the diabetic rats. The aqueous extract caused a significant (P<0.05) reduction in the triglyceride level of treated diabetic rats. The magnitude of reduction was greater than that evoked by glibencla‐ mide. The haemoglobin level of all the animals was increased initially on day 14 with no sig‐ nificant difference except for the glibenclamide-treated animals. Subsequently, there was reduction in the haemoglobin level on day 28 (Table 5). Diabetic dyslipidaemia is marked by elevated triglycerides, cholesterol and low density lipoprotein (LDL) particles of altered composition and decreased high density lipoprotein (HDL), and constitutes an important cardiovascular risk factor in diabetics (Agrawal et al., 2006). Reduction in total cholesterol and triglycerides through dietary or drug therapy has been found beneficial in preventing diabetic complications as well as improving lipid metabolism in diabetic patients (Brown et al., 1993; Ahmed et al., 2001). Experimentally, alloxan-induced diabetic hyperglycaemia is accompanied by increase in serum cholesterol and triglyceride levels (Choi et al., 1991; Ahmed et al., 2001; Okoli et al., 2010) and mimics overt diabetes disease. Thus, in addition to glycaemic control, extract of this plant may further reduce mortality from complications of the disease by ameliorating diabetes-induced dislipidaemia. The RBC count of all the ani‐ mals was reduced on day 14 with all the groups showing significant difference except the 400mg/kg dose of the aqueous extract. Subsequently, there was increase in the RBC count on day 28 with all the groups showing significant difference with the exception of the 400mg/kg dose of the aqueous extract. The white blood cell (WBC) count of all the control and glibenclamide- treated animals was reduced initially on day 14 with no significant dif‐ ference; while there was increase in the WBC count of the extract-treated group on day 14 and the increase continued on day 28 with the 400mg/kg dose of the extract showing signifi‐ cant difference. Likewise, there was subsequent increase in the control (both NDT and NDNT) groups and glibenclamide-treated group on day 28 with no significant difference (Table 6). Again, assessment of the effect of chronic administration of the extracts on haemo‐ globin level as well as white blood cell and red blood cell counts revealed an increase fol‐ lowing an initial reduction in most cases of the experiment. It is not clear if it would progress to a return to basal levels and how long it may take.

**Treatment Dose**

Control (NDNT)

Control (NDT)

**mg/kg**

124 Antioxidant-Antidiabetic Agents and Human Health

Glibenclamide 0.2 Cholesterol

Aqueous Extract 200 Cholesterol

Aqueous Extract 400 Cholesterol

(n=5; mean ± SD.)

2ml/kg Cholesterol Triglycerides Hb

200 Cholesterol Triglycerides Hb

> Triglycerides Hb

> Triglycerides Hb

> Triglycerides Hb

ides calculated for treatment groups relative to diabetic pre-treatment values.

**Parameters Total Cholesterol (mg/dl); Triglycerides (mg/dl); Haemoglobin (g%)**

**Diabetic Post-Rx Day 14 Day 28**

> 126.2±4.6 (-1.3) 117.6±13 (-1.6) 13.3±1.2

> 105.8±7.9a (4.7) 85.4±9.5ab(22.1) 14.1±2.3

110.6±5.2a (3.8) 104.0±4.3b (12.9) 14.3±0.4

88.4±7.1ab (30.9) 109.6±7.6b (22.8) 15.2±1.1

87.0±5.1ab (29.4) 105.6±9.4b (12.7) 14.7±0.8

124.0±9.7 (0.5) 126.4±14.7 (-9.2) 14.0±1.3

109.6±8.5 (1.3) 92.6±11.6b (15.5) 15.5±1.1

118.8±8.6 (-3.3) 111.2±5.0 (6.0) 15.4±1.0b

95.0±7.1ab (25.8) 124.8±5.2ab (12.1) 15.4±0.7

100.0±7.1ab (18.8) 115.2±7.8 (4.8) 15.2±0.8

**Diabetic (Pre-Rx)**

124.6±5.20 115.8±7.4 13.8±0.6

111.0±9.9 109.6±6.5 14.0±0.9

115.0±14.1 119.4±7.5 13.9±0.8

128.0±2.8 142.0±9.0 14.8±1.8

123.2±9.1 121.0±8.8 14.6±1.8

**PreDiabetic (Basal)**

122.4±7.3 114.0±5.7 14.6±0.5

117.2±7.8 106.4±9.0 14.4±1.1

120.8±8.3 104.2±11.2 14.8±1.0

118.6±4.7 114.2±6.1 15.4±2.0

115.0±7.1 114.0±9.2 15.8±1.5

abP<0.05 compared to Basal and Diabetic pre-treatment values respectively (t-Test); Superscripted items (ab) indicate significant values when compared to control and pre-treatment values respectively. NDNT=Non diabetic non treated was a non diabetic control and received the vehicle, NDT = Non diabetic treated was a non diabetic control and re‐ ceived aqueous extract (200mg/kg). Values in parenthesis represent reduction (%) of total cholesterol and triglycer‐

**Table 5.** Effect of Aqueous extract of *P. amarus* on Cholesterol, triglycerides and haemoglobin levels of diabetic rats

Chronic administration of aqueous extract reduced total cholesterol level of diabetic rats. The aqueous extract caused a significant (P<0.05) reduction in the total cholesterol of treated diabetic rats. The magnitude of reduction was greater than that evoked by glibenclamide. Chronic administration of aqueous extract reduced triglyceride concentration of the diabetic rats. The aqueous extract caused a significant (P<0.05) reduction in the triglyceride level of treated diabetic rats. The magnitude of reduction was greater than that evoked by glibencla‐ mide. The haemoglobin level of all the animals was increased initially on day 14 with no sig‐ nificant difference except for the glibenclamide-treated animals. Subsequently, there was reduction in the haemoglobin level on day 28 (Table 5). Diabetic dyslipidaemia is marked by elevated triglycerides, cholesterol and low density lipoprotein (LDL) particles of altered composition and decreased high density lipoprotein (HDL), and constitutes an important cardiovascular risk factor in diabetics (Agrawal et al., 2006). Reduction in total cholesterol and triglycerides through dietary or drug therapy has been found beneficial in preventing diabetic complications as well as improving lipid metabolism in diabetic patients (Brown et al., 1993; Ahmed et al., 2001). Experimentally, alloxan-induced diabetic hyperglycaemia is accompanied by increase in serum cholesterol and triglyceride levels (Choi et al., 1991;


abP<0.05 compared to Basal and Diabetic pre-treatment values respectively (t-Test); Superscripted items (ab) indicate significant values when compared to control and pre-treatment values respectively. NDT = Non diabetic treated was a non diabetic control and received aqueous extract (200mg/kg); NDNT = Non diabetic non treated was a non diabetic control and received the vehicle.

**Table 6.** Effect of Aqueous extract of *P. amarus* on the Red Blood Cell (RBC) and White Blood Cell (WBC) counts of diabetic rats (n=5; mean ± SD.)

There was increase in the body weight of all the groups on day 14 and the increase contin‐ ued on day 28 with the 400mg/kg dose of aqueous extract showing significant difference (P<0.05). The weight increase occurred most in the NDT control group followed by the NDNT control group and then the 400mg/kg dose of aqueous extract (Table 7). Due to the association of obesity with DM, weight control is an important aspect of diabetes manage‐ ment. Poor glycaemic control usually results in weight loss. The results showed that all the animals used gained weight during the study. The weight gain was highest in the nondia‐ betic treated control while glibenclamide-treated control has modest weight gain. In some cases however, adequate glycaemic control by some agents may lead to increase in body weight such as that observed with the thiazolidinediones (Monnier et al., 2003; Bhat et al., 2007). The result showed that at 400mg/kg dose, aqueous extract showed a significant in‐ crease in body weight. It is also important to note that chronic administration of the extracts did not inhibit the natural growth process of these animals with or without diabetes.

amination of the kidney section of diabetic non-treated control showed moderate loss of re‐ nal tubules and congestion of renal blood vessels in the medulla (figure 7). There was no visible lesion seen in the extract-treated (figure 8). There was no visible lesion seen in the glibenclamide-treated group (Figure 9). Several factors such as oxidative stress (Hayden et al., 2005), chronic hyperglycaemia (Leung and Leung, 2008) and autoimmune (Yoshida et al., 1995) or fibrocalculous (Mohan et al., 2008) types of chronic pancreatitis damage the pan‐ creas and impair insulin secretion and hence glycaemic control. Results of histological stud‐ ies on pancreas isolated from treated diabetic rat showed that the extract may have repaired the pancreas damaged by alloxan. Alloxan causes diabetes by destruction of ß-cells of the islet (Szudelski, 2001; Frode and Medeiros, 2008) which consequently impairs insulin secre‐ tion and gives rise to hyperglycemia. Treatment with the extract may have restored the in‐ tegrity and perhaps, functions of the damaged pancreatic tissues. Also, the extract was able to restore the damaged kidney and liver to their normal architecture. Glibenclamide used as a reference hypoglycemic agent did not cause such effect to the same extent as the extract (Figures 1-9). The precise mechanism of this tissue repair is not known. However, due to the large implication of oxidative stress (Hayden et al., 2005; Leung and Leung, 2008) in damage to the pancreas, it seems reasonable to suggest that the antioxidant (Tasaduq et al., 2003) and radical scavenging (Jagetia and Baliga, 2004) effects of this plant may play a key role in pro‐ tecting pancreatic tissues from oxidants including that generated by alloxan. Alloxan de‐ stroys insulin-producing pancreatic ß-cells through the formation of reactive oxygen species

The Antidiabetic Activities of the Aqueous Leaf Extract of Phyllanthus Amarus in some Laboratory Animals

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127

that cause tissue damage (Lee et al., 2008).

**Figure 1.** Pancreas of diabetic non-treated rat (X400)


abP<0.05 compared to Basal and Diabetic pre-treatment values respectively (t-Test); Superscripted items (ab) indicate significant values when compared to control and pre-treatment values respectively. NDT = Non diabetic treated was a non diabetic control and received AE (200mg/kg); NDNT = Non diabetic non-treated was a non diabetic control and received the vehicle. Value in parenthesis represents percentage increase (%) of body weight calculated for treatment groups relative to diabetic pre-treatment values.

**Table 7.** Effect of chronic administration of aqueous extract of *Phyllanthus amarus* on body weight of diabetic rats (n=5; mean ± SD.).

Histological examination of the pancreas shows the necrosis of the islet tissues with the al‐ veolar cells moderately destroyed; there was also moderate congestion of the blood vessels (Figure 1) in the diabetic non-treated group. In the extract-treated group, the architecture of the pancreas appeared intact. The interlobular, intralobular and the alveolar granules were seen (Figure 2). There was slight necrosis of the pancreas around the islet tissues in the gli‐ benclamide-treated group (Figure 3). Microscopical examination of liver section of diabetic non-treated group (Figure 4) showed various degrees of pathological changes such as centri‐ lobular fatty degeneration, cloudy swelling, and vacuolar change of the hepatocytes as well as necrosis of hepatic cells. Microscopical examination of liver section of diabetic extracttreated control group (Figure 5) showed normal arrangement of hepatocytes with clear broad of central vein at portal layer. The histopathological study showed recovery of the damaged liver cells in the extract- treated group. The liver of the glibenclamide-treated group showed widespread vacuolar change of the hepatocytes (figure 6). Microscopical ex‐ amination of the kidney section of diabetic non-treated control showed moderate loss of re‐ nal tubules and congestion of renal blood vessels in the medulla (figure 7). There was no visible lesion seen in the extract-treated (figure 8). There was no visible lesion seen in the glibenclamide-treated group (Figure 9). Several factors such as oxidative stress (Hayden et al., 2005), chronic hyperglycaemia (Leung and Leung, 2008) and autoimmune (Yoshida et al., 1995) or fibrocalculous (Mohan et al., 2008) types of chronic pancreatitis damage the pan‐ creas and impair insulin secretion and hence glycaemic control. Results of histological stud‐ ies on pancreas isolated from treated diabetic rat showed that the extract may have repaired the pancreas damaged by alloxan. Alloxan causes diabetes by destruction of ß-cells of the islet (Szudelski, 2001; Frode and Medeiros, 2008) which consequently impairs insulin secre‐ tion and gives rise to hyperglycemia. Treatment with the extract may have restored the in‐ tegrity and perhaps, functions of the damaged pancreatic tissues. Also, the extract was able to restore the damaged kidney and liver to their normal architecture. Glibenclamide used as a reference hypoglycemic agent did not cause such effect to the same extent as the extract (Figures 1-9). The precise mechanism of this tissue repair is not known. However, due to the large implication of oxidative stress (Hayden et al., 2005; Leung and Leung, 2008) in damage to the pancreas, it seems reasonable to suggest that the antioxidant (Tasaduq et al., 2003) and radical scavenging (Jagetia and Baliga, 2004) effects of this plant may play a key role in pro‐ tecting pancreatic tissues from oxidants including that generated by alloxan. Alloxan de‐ stroys insulin-producing pancreatic ß-cells through the formation of reactive oxygen species that cause tissue damage (Lee et al., 2008).

**Figure 1.** Pancreas of diabetic non-treated rat (X400)

ment. Poor glycaemic control usually results in weight loss. The results showed that all the animals used gained weight during the study. The weight gain was highest in the nondia‐ betic treated control while glibenclamide-treated control has modest weight gain. In some cases however, adequate glycaemic control by some agents may lead to increase in body weight such as that observed with the thiazolidinediones (Monnier et al., 2003; Bhat et al., 2007). The result showed that at 400mg/kg dose, aqueous extract showed a significant in‐ crease in body weight. It is also important to note that chronic administration of the extracts

did not inhibit the natural growth process of these animals with or without diabetes.

**Diabetic (Pre-Rx)**

2ml/kg 214.0±11.2 209.0±14.1 226.6±10.4

200 135.0±36.9 137.0±35.9 150.0±37.5

abP<0.05 compared to Basal and Diabetic pre-treatment values respectively (t-Test); Superscripted items (ab) indicate significant values when compared to control and pre-treatment values respectively. NDT = Non diabetic treated was a non diabetic control and received AE (200mg/kg); NDNT = Non diabetic non-treated was a non diabetic control and received the vehicle. Value in parenthesis represents percentage increase (%) of body weight calculated for treatment

**Table 7.** Effect of chronic administration of aqueous extract of *Phyllanthus amarus* on body weight of diabetic rats

Histological examination of the pancreas shows the necrosis of the islet tissues with the al‐ veolar cells moderately destroyed; there was also moderate congestion of the blood vessels (Figure 1) in the diabetic non-treated group. In the extract-treated group, the architecture of the pancreas appeared intact. The interlobular, intralobular and the alveolar granules were seen (Figure 2). There was slight necrosis of the pancreas around the islet tissues in the gli‐ benclamide-treated group (Figure 3). Microscopical examination of liver section of diabetic non-treated group (Figure 4) showed various degrees of pathological changes such as centri‐ lobular fatty degeneration, cloudy swelling, and vacuolar change of the hepatocytes as well as necrosis of hepatic cells. Microscopical examination of liver section of diabetic extracttreated control group (Figure 5) showed normal arrangement of hepatocytes with clear broad of central vein at portal layer. The histopathological study showed recovery of the damaged liver cells in the extract- treated group. The liver of the glibenclamide-treated group showed widespread vacuolar change of the hepatocytes (figure 6). Microscopical ex‐

**Diabetic Post-Rx Day 14 Day 28**

231.8±7.68 (10.91)

157.0±38.43 (14.60)

200.0±32.6 (6.4)

211.0±22.2 (9.9)

234.0±5.8ab (10.4)

(8.4)

(8.7)

(4.3)

(7.6)

(7.6)

**Treatment Dose mg/kg Body weight (g) Pre-Diabetic (Basal)**

Glibenclamide 0.2 191.0±34.6 188.0±37.9 196.0±33.9

Aqueous Extract 200 196.0±18.1 192.0±18.2 206.6±20.9

Aqueous Extract 400 214.0±15.0 212.0±13.0 228.0±7.8b

groups relative to diabetic pre-treatment values.

126 Antioxidant-Antidiabetic Agents and Human Health

Control (NDNT)

Control (NDT)

(n=5; mean ± SD.).

**Figure 4.** Liver section of diabetic non-treated group (X400)

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129

**Figure 5.** Effect of *P. amarus* extract on the liver of alloxan-induced diabetic rats (X400)

**Figure 2.** Effect of *P. amarus* extract on the pancreas of alloxan-induced diabetic rats (X400)

**Figure 3.** Effect of glibenclamide on the pancreas of alloxan-induced diabetic rat (X400)

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**Figure 4.** Liver section of diabetic non-treated group (X400)

**Figure 2.** Effect of *P. amarus* extract on the pancreas of alloxan-induced diabetic rats (X400)

128 Antioxidant-Antidiabetic Agents and Human Health

**Figure 3.** Effect of glibenclamide on the pancreas of alloxan-induced diabetic rat (X400)

**Figure 5.** Effect of *P. amarus* extract on the liver of alloxan-induced diabetic rats (X400)

**Figure 8.** Effect of *P. amarus* extract on the kidney of alloxan-induced diabetic rats (X400)

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131

**Figure 9.** Effect of glibenclamide on the kidney of alloxan-induced diabetic rat (X400)

**Figure 6.** Effect of glibenclamide on the Liver of alloxan-induced diabetic rat (X400)

**Figure 7.** Kidney section of diabetic non-treated group (X400)

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**Figure 8.** Effect of *P. amarus* extract on the kidney of alloxan-induced diabetic rats (X400)

**Figure 6.** Effect of glibenclamide on the Liver of alloxan-induced diabetic rat (X400)

130 Antioxidant-Antidiabetic Agents and Human Health

**Figure 7.** Kidney section of diabetic non-treated group (X400)

**Figure 9.** Effect of glibenclamide on the kidney of alloxan-induced diabetic rat (X400)
