Antioxidant role of mulberry (Morus indica L. cv. Anantha) leaves in streptozotocin-diabetic rats

Antioxidant role of mulberry (Morus indica L. cv. Anantha)leaves in streptozotocin-diabetic rats

• Bondada Andallua *, N.Ch. Varadacharyulub

• a Department of Home Science, Sri Sathya Sai Institute of Higher Learning, Anantapur-515001, India

• b Department of Biochemistry, Sri Krishnadevaraya University, India

系別：生科四甲

學號：91390391

姓名：吳佳煒Received 20 December 2002 received in revised form 7 July 2003; accepted 7 July 2003

Abstract• The antihyperglycemic and

antioxidant role of mulberry (Morus indica L.) leaves were investigated.

Model ： Wistar ratsI. Standard dietII. 25% dry mulberry leaf powder and

standard dietFor 8 weeks

Abstract

antihyperglycemic and antioxidant role of mulberry effect ：

• on blood glucose • lipid peroxidation• reduced glutathione (GSH) concentrations

and on the activity of glucose-6-phosphate dehydrogenase (G6PDH)

• various antioxidant enzymes in erythrocytes

♠Key point ：

Abstract

lipid peroxidation

fasting blood glucose concentrations glutathione GSH concentrations activity of glucose-6-phosphate

dehydrogenase (G6PDH) antioxidant enzymes

Results ：

Introduction

• Hyperglycemia 血糖過高症• Free radicals result in the consumption

of antioxidant defenses may lead to ：a. disruption of cellular functionsb. oxidative damage to membranesc. enhance susceptibility to lipid peroxidation.

Introduction• Total antioxidant status (TAS) of

serum is reduced in type I diabetes• The reactive oxygen species are

modulated by antioxidant enzymes ：Glutathione reductase (GR) glutathione peroxidase (GPx)glutathione-S-transferase (GST)superoxide dismutase(SOD) catalase (CAT) non-enzymatic scavengers like reduced

glutathione.

Introduction• Mulberry (M. alba L.) leaves containing many

nutritional components ：• Flavones 黃酮• Steroids 類固醇• Triterpenes 三烯• amino acids 氨基酸• Vitamins 維生素• Moracin 桑辛素• other trace minerals 無機物

Materials

• Male rats of Wistar strain from Hyderabad

weight range 150~200gair-conditioned room (25° ±1℃)light from 7 a.m. to 7 p.m.Divide into 4 groups

Animals

Materials

I ： normal control II ： normal treated with

mulberry leaf powder III ： diabetic controlIV ： diabetic treated with

mulberry leaf powder

Wistar rats

Materials

• The mulberry leaves (M. indica L. cv. Anantha)

• The 4th and the 5th leaves from the apex of healthy plants were plucked

• washed thoroughly under running tap water

• shade dried for 3 days and ground to a fine powder in an electric mixer

Leaves

MethodsGroups III and IV (diabetic)by a single i.p. injection of streptozotocin

(STZ) (55 mg/kg) prepared in 1 ml of freshly prepared 0.1 mol/l citrate buffer after an overnight fast.

Groups I and II (Control) were injected with citrate buffer alone.

Streptozotocin injected animals were given 5% glucose water for 24 h following streptozotocin injection to prevent initial drug-induced hypoglycemic mortality

Methods

•注射 streptozotocin ，以破壞分泌胰島素的β胰島細胞，進而形成高血糖的情形 。

•增加大鼠之進食量、飲水量及排泄量，並使體重變輕、血糖升高。

•人類糖尿病的症狀：吃多、喝多、尿多

streptozotocin

Methods - Biochemical estimations

• Erythrocytes were separated from whole blood

• Erythrocytes were washed thrice with 0.9% NaCl

• suspended in 1 volume of 0.9% NaCl• The packed cell volume was adjusted

to 5% with PBS (pH 7.4)

Student's T test

n

tsX

Results & Discussion

Fast

ing

Blo

od

Glu

cose

Fast

ing

blo

od g

luco

se

decreased food consumption insignificantly

increased the body weight in diabetic rats

• Mulberry decreased food consumption

insignificantly increased the body weight in

diabetic rats

fagomine which potentiates the glucose induced insulin release similar to the action of glibenclamide a sulfonylurea drug which triggers the release of endogenous insulin

increase in tissue uptake of glucose by mulberry leaves

桑葉生物鹼 fagomine 可顯著增加葡萄糖引起的胰島素含量增加，從而降低糖尿病小鼠血糖。

The effect of mulberry in controlling hyperglycemia and glycosuria could be due to:

the N-containing sugars isolated form mulberry leaves which inhibit the functions of

α-glucosidaseα-mannosidase β-galactosidase

glucose-6-phosphate dehydrogenase 13%

glutathione reductase 34%glutathione peroxidase 20%glutathione-S-transferase 30%superoxide dismutase 46%Catalase 59%p < 0.01

diabetic control rats vs. normal controls

CATALASE 可氧化分解身體內過量的尿酸 . 將 H2O2 還原成 H2O 的反應 Glutathione peroxidase: 催化以 glutathione 為還原劑，將 H2O2 還原成 H2O 的反應

• The activity of glucose-6-phosphate dehydrogenase (69%; p < 0.01)

• glutathione reductase (95%; p < 0.01), glutathione peroxidase (151%; p < 0.01)

• glutathione-S-transferase (24%; p < 0.01)• superoxide dismutase(106%; p < 0.01)• activity of Catalase 33% all p < 0.01

Diabetic control v.s mulberry

Conclusion• Mulberry leaves are palatable and

effective in controlling hyperglycemia and glycosuria in STZ-diabetic rats.

• The leaves exerted a rapid protective effect against lipid peroxidation by scavenging O2 and elevating the activities of antioxidant enzymes by virtue of antioxidant flavonoids and moracins present in the leaves.

類黃酮 flavonoid 一類不含氮的生物色素，包括花色素 &FAA1; 和花黃色素。類黃酮在植物中存在普遍，但在動物中出現較少，具有抗癌的作用。

桑辛素 Moracin 這類化合物顯示了良好的抗菌和抗真菌作用，是植物抗真菌抗生素。

Question & Answer

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