A Review On Hepatotoxicity

Liver is the principle organ for maintaining the body’s internal environment.  The liver has a major influence on the flow of nutrients the rest of the body’s, it control the metabolism of carbohydrate, proteins and fats.

Liver is also the biggest reticulo- endothelial organ in the body as such has important immune function in maintaining body integrity. The herbal drugs derived from plants posses various medicinal value. We, the human beings, posses a huge wealth of medicinal plants which have been explored and validated for their therapeutic properties, still there are so many plants whose medicinal properties are not yet published and lots of research works are needed to be carried out on such medicinal plants.   

Introduction

 Liver¹

Anatomy-

The liver is the largest gland of the body enclosed within the right lower rib cage beneath the diaphragm. it is almost completely covered by visceral peritoneum and a dense irregular connective tissue layer that lies deep to the peritoneum. Liver is divided in two principle lobes, a large right lobe and a smaller left lobe separated by falciform ligament. The right lobe is considered by many anatomists to include an inferior quadrate lobe and a posterior caudate lobe. Liver has five surfaces as anterior, posterior, superior, inferior, and right.

Structure- (Histology)

The lobes of liver are made up of many functional units called lobules. A lobule consists of specialized epithelial cells called hepatic cells or hepatocytes arranged in irregular, branching, interconnected plates around the central vein. Rather than capillaries liver has larger space lined by endothelium called sinusoids through which blood passes. The sinusoids are also partly lined with stellate reticuloendothellial (Kuffer’s) cells. These phagocytes destroy worn out white and red blood cells, bacteria and toxic substances. Bile secreted by hepatic cells enters bile capillaries that empty into small bile ducts. These ducts eventually merge to form the larger right and left hepatic duct, which unite and exit the liver as the common hepatic duct. Further this common hepatic duct join the cystic duct from the gall bladder to form the common hepatic duct. The common hepatic duct and pancreatic duct enter the duodenum in a common duct called the hepatopancreatic ampulla.

Blood Supply-

The liver receives blood from two sources, from hepatic artery it obtains oxygenated blood and from hepatic portal vein it receives deoxygenated blood containing newly absorbed nutrients. Branches of both the hepatic artery and the hepatic portal vein carry blood into liver sinusoids, where oxygen, most of the nutrients and certain poisons are excreted by hepatic cells. the reticuloendothellial (Kuffer’s) cells lining the sinusoids phagocytes microbes and bits of foreign matter from the blood. Branches of hepatic portal vein, hepatic artery and bile duct typically accompany each other in their distribution through the liver. Collectively, these structures are called as ‘Portal traid’

Functions of liver-

• Secretion and excretion of bile

Bile is partially an excretory product and partially a digestive secretion. Each day the hepatic cells secretes 800-1000 ml of bile, a yellow, brownish or olive green liquid. It has PH of 7.6-8.6.

Bile mainly consists of water, bile salts, cholesterol, a phospholipid called lecithin, bile pigments, and several ions. The principle bile pigment is bilirubin. When worn out red blood cells broken down, iron, globins, and bilirubin (derived from heam) are released.

• Metabolic functions

Carbohydrate metabolism  

Liver maintains the normal blood glucose level. It can converts glucose to glycogen (Glycogenesis) when blood sugar level is high and brekdown of glycogen to glucose (Glycogenolysis) when blood sugar level is low. Also liver can converts amino acid and lactic acid to glucose (Gluconeogenesis) when sugar level is low.

Lipid metabolism

Liver stores some triglycerides (neutral fat) breakdown fatty acids into acetyl coenzyme –A, this process is called as b oxidation and converts excess acetyl coenzyme A into ketone bodies (Ketogenesis). It synthesizes lipoproteins. Hepatic cells synthesizes cholesterol and use cholesterol to make bile salts.

Protein metabolism

The liver deaminates (remove the amino group,NH₂) from amino acids so that they can be used for ATP production. It converts the resulting toxic ammonia (NH₃) into the much less toxic urea for excretion in urin.

Hepatic cells synthesize plasma proteins such as alpha and beta globulins, albumin, prothrombin, and fibrinogen.

Haematological functions- ( Haematopoeisis and coagulation)

1. Blood formation in the embryo(and in some abnormal states in the adults)
2. Production of fibrinogen, prothrombin, heparin, and other clotting factors VII, VIII, IC and C.
3. Destruction of erythrocytes.(at the end of their respective life span)

Circulatory function

1. Transfer of blood from portal to systemic circulation
2.  Activity of its reticuloendothelial system (Kupffer’s cells)in immune  mechanism.

Blood storage.(regulation of blood volume)

Detoxication and protective functions

1.Kupffer cell activity in removing foreign bodies from blood(phagocytosis)

2.Detoxiocation by conjugation, methylation, oxidation and reduction

3.Removal of ammonia from blood particularly that absorbs from the intestine by way of the portal vein.

Drug metabolism

Liver plays a vital role in biotransformation of  drugs. It converts drug molecule from non polar to polar. These non polar drugs can be conjugated with more polar compounds, which make it water soluble for the urinary excretion.

Liver Diseases-

Jaundice-

This is the yellow pigmentation of the skin, mucous membrane and deeper tissues due to increased bilirubin level in blood. The normal serum bilirubin level is 0.5to 1.5 mg%. When this exceeds 2 mg % ,jaundice occurs.

Types and causes of Jaundice

Jaundice is classified into three types namely haemolytic jaundice, hepatocellular jaundice, and obstructive jaundice.

1. Haemolytic Jaundice-Haemolytic jaundice is otherwise called prehepatic jaundice. During this , the excretory function of liver is normal. But , there is excessive destructionof red blood cells and thus the bilirubin level in blood is increased the liver cells can not excrete than much bilirubin rapidly. So , it accumulate in the blood resulting in jaundice. In this type of jaundice the free bilirubin level increases in blood. The formation of urobilinogenalso is more resulting in the excretion of more amount of urobilinogenin urine. Any condition that causes haemolytic anemiacan lead to haemolytic jaundice.
2. Hepatocellular Jaundice- The jaundice due to the damage of liver cells is called hepatocellular or hepatic jaundice. It is also called hepatic cholestatic jaundice. Here, bilirubin is conjugated . but the conjugated bilirubin cannot be excreted. So , it returns to the blood. The damage of liver cells occurs because of toxic substances(toxic jaundice) or by infection(infective jaundice). Commonly liver is affected by virus resulting in hepatitis.
3. Obstructive Jaundice- This is otherwise called extrahepatic cholestatic jaundice or posthepatic jaundice. It is due to the obstruction of bile flow at any level of biliary system. The bile can not be poured into small intestine and bile salts and bile pigments enter the circulation. In this , blood contains more conjugated bilirubin. The important differences between haemolytic jaundice and obstructive jaundice are given in table no. 1

Table No.1 Difference between Haemolytic Jaundice and Obstructive Jaundice.

Features	Haemolytic Jaundice	Obstructive Jaundice
Serum bilirubin level	High with more free bilirubin	High with more conjugated bilirubin
Urobilinogen in urine	More	Absent
Bile salts and bile pigments in urine	Absent	Present
Van den Bergh’s reaction	Indirect- positive	Direct- positive
Liver functions	Normal	Exaggerated
Hemorrhagic tendency	Absent	Present due to lack of vitamin K

Hepatitis²

Hepatitis is a liver disease characterize by swelling and inadequate functioning of liver. Hepatitis may be acute or chronic. In severe conditions, it may lead to liver failure and death.

Causes and Types

Hepatitis is caused by viruses, bacteria poisons, autoimmune disease drug abuse, alcohol, some therapeutic drugs and inheritance from mother during parturition. Viral hepatitis is of five types namely, hepatitis A, B, C, D and E.

Hepatitis A and E are caused mostly by intake of water and food contaminated with hepatitis virus. Generally these two types of hepatitis are not life threatening.

Hepatitis B,C and D are caused by sharing needles with infected person, accidental prick by infected needle, having unprotected sex with infected person, inheritance from mother during parturition and blood transfusion from infected donors. These three forms of hepatitis are serious diseaseswhen compared to hepatitis A and E.Among these , hepatitis B is more common and considered more serious because it may lead to cirrhosis and cancer of liver.

Cirrhosis ³

The inflammation and damage of parenchyma of liver is known as cirrhosis of liver. This may results in degeneration of hepatic cells and dysfunction of liver.

Cirrhosis is a diffuse, chronic, necrotic(degenerative) liver disorder characterized by progessive hepatocyte injuryfoillowed by regeneration and fibrosisleadind to disorganization of lobular architecture, pseudolobule formation and acquired vascular malformation.

Characteristic features

• Disorganized architecture of liver due to necrosis, fibrosis and regeneration.
• Fibrosis –Broad scars
• Parenchymous nodules (psedolobule) formation due to regenerative activity, fibrosis and scar formation. these nodules are called as micronodules(if less than 3 mm) and macronodules(if more than 3 mm)

Development of portal hypertension and their complications.

Complications

·Progressive liver failure

·portal hypertension and their complications

·hepatocellular carcinoma

Tumors Of Liver³

Benign tumors

I) Benign haemangioma

ii)Cysts

·simple cyst

·Conjugated intrahepatic biliary dilatations.

·Choloedochal cyst

·Polycystic liver disease

iii)Focal hyperplasia

iv)Adenoma

·Bile duct adenomas

·Liver cell adenomas

Malignant tumors

i)Secondary metastasis are the most common tumors.which may be from breast ,lungs and colon.

ii) Primary tumors

·Hepatoblastoma

·Angiosarcoma

·Primary carcinoma of liver

-Hepatocellular carcinoma

-Cholangiocarcinoma

Hepatocellular Carcinoma³

It is the most common primary liver cancers (comprising 90% of all tumors).

Etiology and Pathogenesis

• Protracted infection with hepatitis B virus.
• Cirrhosis
• Environmental toxins e.g.alpha toxinsB, produced by Aspergillus flavus.
• Oral contraceptive questionable role.

Hepatocellular Failure ⁵

It may occure due to-

• Ultra structural lesions of hepatocytes e.g. reye’s syndrome, drugs.
• Chronic liver diseases e.g. chronic hepatitis, cirrhosis, Wilson’s disease.
• Massive hepatic necrosis fulminant viral hepatitis.

Clinical features

• Jaundice
• Hypoalbuminemia
• Hyperammonemia
• Increased serum level of hepatic enzyme e.g. SGPT, SGOT
• Hepatorenal syndrome
• Hepaticencephalopathy
• Coma

Hepatic Encephalopathy³

Also called as hepatic coma is a feature of acute of chronic liver failure.it is a metabolic disorder of the central nervous system and neuromuscular system associated with hepatic failure. It is reversible condition.

Clinical features

• Nonspecific, electroencephalographic(EEG) changes.
• Disturbed consciousness progressing to coma.
• Fluctuating neurologic signs.
• Progressive confusion , drowsiness and coma which may lead to death.

Hypothesis

• Ammonia hypothesis- less degradation of ammonia to urea by liver leads to toxic damage to brain by hyperammonia.
• Synergistic neurotoxin hypothesis-encephalopathy due to combined action of ammonia, mercaptans and short chain fatty acids.
• The false neurotransmitter hypothesis- the normal neurotransmitter dopamine in brain is replaced by false neurotransmitter like GABA or octopamine.
• The amino acid hypothesis- e.g. elevated plasma level of tryptophan and its metabolite, serotonin may be toxic to the brain.

Portal Hypertension³

In this condition, increased resistance to portal blood flow. It may occur in the following conditions.

i)Prehepatic  

·Portal vein thrombosis

·Splenomegaly

ii) Intrahepatic

·Cirrhosis

·Miliary Tuberculosis

·Idiopatic

iii) Post Hepatic

·Severe right heart failure

Major Consequences

i)Ascitis: the collection of excess fluids (>500 ml) in peritoneal cavity. Ascitis may occur due to increased hepatic lymph formation and retention of sodium and water.

ii)Splenomegaly: it is congestive in nature.it might be up to 1000gms and may lead to hypersplenism.  

iii)Hepatic encephalopathy:  it is usually associated with cirrhosis, portosystemic shunting, sudden drainage of large volume of ascitis, massive hematemesis, infection,stress, operation, electrolyte imbalance, drugs or protein loss.

Hepatotoxicity

Toxic liver injury produced by drugs and chemicals may virtually mimic any form of naturally-occuring liver disease. Hepatoprotective effect were studies against chemicals and drugs induced hepatotoxicityin rats like alcohol, CCl₄, galactosamine, paracetamol, isoniazid  rifampicin etc.

Classification of hepatotoxins

A) Intrinsic:  

It consists of agents that are predictable hepatotoxins.they are recognized by high incidence of hepatic injury in exposed individuals and in experimental animals.There is a consistant latent period between exposure to a particular agent and the development of hepatic injury and the injury appeared to be dose related.^4-5  

There are two types of intrinsic hepatotoxins:

1.Direct hepatotoxins:

It may be so called because they (or their metabolic products) produce direct injury to hepatocytes and its organelles, especially the endoplasmic reticulum. CCl₄, the prototype , produces peroxidation of the membrane lipids and other chemicals that lead to degeneration of the membranes.

2.Indirect hepatotoxins:  

They are anti-metabolites and related compounds that produce hepatic injury by interference with the specific metabolic pathway or processes.the structural injury produced by indirect hepatotoxins appear to be secondary to a metabolic region , while in that produced by dirct hepatotoxins, the metabolic dearangement is secondary to the structural injury. The hepaticv damage produced by indirect hepatotoxins may be mainly cytotoxin injury (by interfering with metabolic pathway or processes essential for parenchyma integrity)expressed as steatisis or necrosis, or may be mainly cholestasis,interfering only or mainly with biliary secretion.

3.Host idiosyncrasy: 

It consists of agents that are not predictably hepatotoxic , but produces hepatic injury in only a small portion of exposed individual , who are uniquely susceptible. In several instances auto antibodies directed against normal cellular constituents are detected. The injury does not appear to be dose related  and is not reproducible in experimental animals and appears after a variable latent period.⁶

CCl₄ induced hepatotoxicity    

The drug is metabolized in endoplasmic reticulum and mitochondria with the formation of CClO_{3 -}, the reactive oxidative free radical intermediate generated by cytochrome P-450, the nascent oxygen O^- resulted via lipoperoxidation causes rise in intracellular reactive Fe⁺² ions, aldehyde and depletion GSH, and calcium sequestration. Oxidative CCl₃O^- also by direct covalent interaction induces degeneration  of Ca⁺² sequestration. Failure into sequestration results in increased intracellular Ca⁺²,aggregation by proteolytic enzyme and causes an increase in Fe⁺² ions, which in turn by lioid peroxidation precipitates aldehyde cytotoxicity.⁷

CCl₄-----------------------------àCCl₃O^- + O^-

Galactosamine induced hepatotoxicity

It resembles to that caused by acute human viral hepatitis. The cholestasis caused by galactosamine may be from its damaging effects on bile ducts or ductless or canalicular membrane of hepatocytes.⁸

Alcohol induced hepatotoxicity

Ethanol produces constellation of dose- related deleterious effects in the liver. the primary effects are fatty infiltration of the liver , hepatitis and cirrhosis.  Because of its intrinsic toxicity, alcohol cal injure the liver in the absence of dietary deficiencies.  The accumulation of fat in the liver is an early event and can occur in normal individual after the ingestion of relatively small amount of ethanol.this accumulation results from inhibition of both the tricarbixylic acid cycle and oxidation of fat, in part owing to the degeneration of excess NADH produced by the action of alcohol dehydrogenase and aldehyde dehydrogenase.

Fibrosis resulting from tissue necrosis and chronic inflammation, is the underlying cause of alcoholic cirrhosis. Normal liver tissue is replaced by fibrous tissue. Alcohol can affect directly stellate cells in the liver , causing deposition of collagen around terminal hepatic venules.chronic alcohol use is associated with transformation of stellate cells into collagen- producing myofibroblast-like cells. The histologic hallmark of alcoholic cirrhosis is the formation of Mallory bodies, which are thought to be related to an altered cytokeratin intermediate cytoskeleton. A number of underlying molecular mechanism have been proposed.⁹

Paracetamol induced hepatotoxicity  

The liver damage associated with paracetamol overdose is due to the formation of a hepatotoxic metabolite. Therapeutic doses of paracetamol are metabolized mostly to sulphate and glucuronide conjugates. The rest is metabolized to a reactive intermediate which is detoxified by conjugation with glutathion. In overdose, the sulphate and glucuronide conjugation pathways are saturated and more drug is converted to the reactive metabolite. The glutathione  available for its detoxification is rapidly depleted and the metabolites accumulated and binds covalently to liver cell proteins, causing irreversible damage. Liver damage can be prevented by providing glutathione like substances, such as acetylcysteine, so that the reactive metabolite can be removed by conjugation and the liver cells are protected.¹⁰

Table no. 2 Classification of hepatotoxin.

Category of agent	Mechanism	Histological lesion	Examples
1.Intrisic toxicity a) Direct	Membrane injury destruction of structural basis of cell metabolism	Necrosis (zonal)and /or steatosis	CCl4, CHCl3, phosphorus
b)Indirect Cytotoxic	Interference with specific metabolic pathway leads to structural injury	Steatosis or Necrosis	Ethionine,Thioacetamide, Paracetamol, Ethanol
c) Cholestatic	Iinterference with hepatic excretory pathway leads to cholestasis	Bile duct injury	Rifampicine , Steroids
2.Host idiosyncrasy a) Hypersensitivity	Drug allergy	Necrosis or cholestasis	Sulfonamides Halothane
b)Metabolic Abnormality	Production of hepatotoxic metabolites	Necrosis or cholestasis	Isoniazid

4.Liver Function Tests¹¹

In keeping with the multiplicity of thwe liver function ,a variety of tests are available to access them. The choice of the test is influenced by its simplicity , reliability, and sensitivity as well as particular function one is interested in accessing.

1.Test of bilirubin metabolism

a)Estimation of serum bilirubin

Bilirubin levels are elevated in all types of Jaundice. The ratio of thwe conjugated to unconjugated bilirubin giving an idea of the type of Jaundice.

b)Urinary bilirubin 

Elevation of warer soluble conjugated bilirubin glucoronides in urine occur in obstructive jaundice.

c)Urine urobilinogen

Abnormally low level or absence of urobilinogen in urin in diagnostic of biliary obstruction , while it may be increased in other types of jaundice.

2.Test of protein synthesis and metabolism       

a)Estimation of plasma protein

Electrophoresis is very useful in detection of impaired liver function or hepatic failure.

b)Albumin Globulin ratio (A/G rati)

It is normally 1.2 to 1.4 and may be reversed in liver disorders.

c)Flocculation tests

The most commonly used are the Thymol turbidity and Zinc sulphate turbidity tests.

d)Plasma prothrombin and prothrombin time

In severe liver dysfunction , prothrombin synthesis impaired due to  poor absorption of vitamin K leading to low plasma prothrombin levels and a prolonged prothrombin time.Coagulation time also prolonged.

3.Test based on excretory function

a)Serum alkaline phosphatase

It is an enzyme excreted normally by liver. Alkaline phosphatase levels in serum are abnormally high in biliary obstruction.

b)Bromsulphthalein (BSP) Excretion

BSP is a dye which is rapidly excreted by the liver. It is chiefly used to assess the liver cell dysfunction in the absence of jaundice.

4.Test to assess hepato- cellular damage

a)Serum enzyme estimation

Intracellular enzyme such as serum glutamic oxaloacetic transminase (SGOT) and serum glutamic pyruvic transminasde  (SGPT) are released in hepato cellular damage , thus elevating the serum level of this  enzyme. Isocitrate dehydrogenase and certain isozymes of lactic dehydrogenase are also elevated in liver cell damage.  Serum transminase levels (SGOT & SGPT) are markedly elevated in active hepatitis.

As a general rule liver function test are employed either to assist in the differential diagnosis of jaundice or to detect and assess the extent of hepatocellular damage.

5. Parameters Reflecting Liver Condition And Their Interpretation:

Transaminases¹²

Transaminase is a process in which an amino group is transferred from an amino acid to an alpha – keto acid. It is an important step in the metabolism of amino acids. The enzyme responsible for transamination are called tranaminases ( now called amino-transferases). Two diagnostically useful transaminases are glutamate oxaloacetate transaminase or SGOT and glutamate pyruvate transminase or SGPT. These enzyme catalyze the following reaction.

GOT/AST

L- aspartate +Oxoglutarate ---------------àOxaloacetate + Glutamate

(or ketoglutarate)

L- alkaline +Oxoglutarate-----------------à Pyruvate + Glutamate

(or ketoglutarate)

Clinical significance

Increased serum transaminase activity is seen in liver dysfunction. Greater activity of SGOT (AST) over SGPT (ALT) is typical of myocardial infraction.

Serum glutamate pyruvate transaminase (SGPT)

Principle

SGPT (ALT) catalyzes the transfer of amino group from L- alanine to alpha- ketoglutarate to yield pyruvate and L-glutamate. Lactate dehydrogenase then converts pyruvate and NADH into lactate and NAD. The conversion on NADH to NAD decrease the absorption at 340 nm . the rate of decrease in absorbance is measured and is proportional to the SGPT activity.

GPT (ALT)

L-alanine +a- ketoglutarate --------------à L-Glutamate + pyruvate

LDH

Pyruvate +NADH +H⁺ --------------------à  Lactate + NAD⁺

Clinical significance

Elevation of SGPT (ALT) activity is found in liver and kidney diseases such as infectious or toxic hepatitis, infectious mononucleosis and cirrhosis. Moderate increase is also found in obstructive jaundice, metastasis carcinoma, hepatic congestion and myocardial infraction.

SGPT levels may be decrease in patients undergoing long term hemodialysis without supplemental vitamin therapy.

Normal value

SGOT(AST) : 7 – 21 U/L

SGPT(ALT) : 6 –21 U/L

Serum glutamate oxaloacetate transaminase (SGOT)

Principle

SGOT (AST) catalyzes the transfer of the amino group from L- aspartate to alpha – ketoglutarate to yield oxaloacetate and L- glutamate. Malate dehydrogenase (MDH) , then converts oxaloacetate and NADH to malate and NAD. The conversion of NADH to NAD decreases the absorbance at 340 nm, the rate of which proportional to  the SGOT activity.

GOT (AST)

L- aspartate + a-ketoglutarate ----------------------à Oxaloacetate + L-glutamate

MDH

Oxaloacetate +NADH +H⁺--------------------------à L- malate +NAD⁺

Clinical significance

Organ rich in SGOT (AST) are heart , liver and skeletal muscle.when any of these organs are damaged , the serum GOT level rises in proportion to the severity ofd damage. In myocardial infraction SGOT starts increasing by 3-9 hours , peaks on second day returnto normal on 4^th-6^th day. In hepatitis , SGOT peaks usually between 7-12 days and any increase upto 100 times. Increased levels SGOT are also found in mononucleosis, pancreatitis, trauma of skeletal muscle ,renal necrosis and cerebral necrosis.

Phosphatases¹²

Phosphatases belog to the class of enzyme called hydrolases and they are characterized by their ability to hydrolyse a large variety of organic phosphate with the formation of an alcohol and phosphate ions.

Phosphatases of diagnostic significance are- alkaline phosphatase and acid phosphatase. These are differentiated by their reaction in alkaline and acidic medium. The PH for measuring the alkaline phosphatase activity is 10 and for acid phosphatase it is 5.

Alkaline Phosphatase (ALP)

Principle 

The substrate, p-nitrophenyl phosphate (PNPP) is hydrolysed by ALPto p- nitrophenol and phosphoric acid . Some divalent ions like Mg⁺⁺ are added to the system which acts activators. PNPP is colourless in acid or alkaline medium while PNP is yellow in colour in the alkaline medium and colourless in the acid medium.

ALP/ACP

P-Nitrophenyl phosphate +H₂O ----------------à p- nitrophenol + H₃PO₄

                   Colourless                                                                  Yellow

Clinical significance

Increased alkaline phosphatase activity may be related to hepatobiliary abd bone disease. Very high alkaline phosphatase activity in serum is seen in patient with bone cancer and marked increased also occur in obstructive jaundice and biliuary cirrhosis. Moidetrate elevations have been notedvin case Hodgkin’s disease, congestive heart failure, infective hepatitis and abdominal problems.

Normal value

Alkaline phosphatase (ALP) : 20 to 100 U/L

Gamma-Glutamyl Transpeptidase (GGTP)

Principle

Gamma –glutamyl transpeptise catalyses transfer of gamma- glutamyl group from the substrate gamma- glutamyl para – nitroanilide to glycylglycine releasing free P- nitroaniline which absorbs light at 405 nm. Enzyme activity is proportional to the increase absorbance at this wave length.

GGTP

g-glutamyl nitroanilide + glycylglycine ----------------à P-nitroaniline + Glutamyl  glucylglycine

Clinical significance

Elevated serum GGTP levels appear to be indicative of disease of liver ,biliary tract and pancreas. Serum GGTP activity is usully elevated in the cases of cholesystitis, cholangitis, cholelithiasis, chronic hepatitis, viral hepatitis and netastatic carcinoma.

GGTP is particularly helpful in clinical assessment of alcoholic cirrhosis. Since setrum GGTP is not elevated in any form of bone disorder, it assay has been valuable in differentiating bone and liver disease in conjunction with alkaline phosphatase determination.

Normal values

Gamma-glutamyl transpeptidase (GGTP) : 5 –24 IU/L

Serum Bilirubin

Bilirubin in serum would only react with daizo reagent in the presence of alcohol , after the proteins had been removed by precipitation. Addition of alcohol to the reaction gives positive test for both conjugated and unconjugated bilirubin pigment. The unconjugated bilirubin level is then estimated by substracting direct bilirubin value from this total value.

Normally,0.25 mg/dlof conjugated bilirubin is present in the blood of an adult. Bilirubin rises in disease of hepatocytes, obstruction to biliary excretion into duodenum, in hemolysis and defects of hepatic uptake and conjugation of bilirubin treatment such as Gilbert’s disease.¹³

Serum Protein

Liver cells synthesise albumin, fibrinogen, prothrombin, alpha- 1antitrypsin, hepatoglobin,ceruloplasm , transferring alpha foetoproteins and acute phase reactant proteins. The blood levels of these plasma proteins are decreased in extensive  liver damage. A routinely estimated total protein is in the normal range of  5.5 to 8 gm/dl. Hypoalbuminanemia may occur in liver disease having significant destruction of hepatocytes. Hyperglobulinaemia may be present in chronic inflammatory disordes such as in cirrhosis and chronic hepatitis.¹³

Morphological Parameters

Morphological like weight of the animals, weight and volume of the liver have also been used to evaluate the protective effect of the drug.¹⁴

Table No. 3 Plants Investigated For Its Hepatoprotective Activity

S.No.	Plant Name	Part used	Extract/ Constituents	Experimental model	References
1.	Abutilon indicum	-	Aqueous	CCl4	15
2.	Adhatoda vasica	Leaves	-	D-galactosamine	16
3.	Andrographis paniculata	Leaves	Aqueous	CCl4	17
4.	Anisotes trisulcus		Ethanolic	CCl4	18
5.	Apium graveolens Linn.	Seeds	Methanolic	Paracetamol and thioacetamide	19
6.	Apium graveolens Linn.		Methanolic	CCl4	20
7.	Aronia melanocarpa	Fruit	Juice	CCl4	21
8.	Artemisia absinthium		Aqueous methanolic extract	Acetaminophen and CCl4	22
9.	Artmisia vulgaris	Aerial parts	Aqueous methanolic	d- Galactosamine (D-GaIIN) and Lipopolysaccharide (LPS)	23
10.	Asteracantha longifolia	Seed	Methanolic	Acetaminophen	24
11.	Azadirachta indica	Leaves	Ethanolic	Paracetamol	25
12.	Ballota glandulosissima		Aqueous	CCl4	26
13.	Barleria prionitis Linn.	Aerial	Methanol water	CCl4, galactosamine, and paracetamol	27
14.	Belamcanda chinensis	Rhizomes		CCl4	28
15.	Beta vulgaris	Root	ethanolic	CCl4	29
16.	Camellia sinensis	Leaves	Decoction	Tamoxifen  citrate (TAM)	30
17.	Cassia occidentalis L.	Leaves	Aqueous ethanolic	Paracetamol and ethyl alcohol	31
18.	Centaurium erythraea L.	Leaves	Methanolic	Acetaminophen	32
19.	Coronopus didymus L.	Whole plant	Aqueous extracts		33
20.	Cudrania tricuspidata Breau	Root, Bark	Methanolic	Nitrofurantoin	34
21.	Embellica officinalis	Fruit	Hydroalcoholic	Rifampicin (RIF), isoniazid(INH), and pyrazinamide (PZA) (in combination)	35
22.	Erycibe expansa	Stem	Methanolic	D-galactosamine	36
23.	Eucalyptus maculata	Stem	Chloroform	Acetaminophen	37
24.	Helminthostachys zeylanica L.	Rhizome	Methanolic	CCl4	38
25.	Nymphaea stellata willd	Flower		CCl4	39
26.	Osbeckia octandra	Mature leaves	Aqueous	Galactosamine and tert-butyl hydroperoxide	40
27.	Permna tomontosa L.	Leaves		Acetaminophen	41
28.	Phyllanthus maderaspatensis	Whole plant	n-hexane, ethanol or water	Acetaminophen	42
29.	Psidium guajava Linn.	Leaves		CCl4	43.
30.	Quercus aliena acorn		Aqueous	CCl4	44
31.	Rosmarinus officinalis	Young sprouts and total plant	Aqueous and ethanolic extracts	CCl4	45
32	Sesbania grandiflora	Leaves	Ethanolic	Erythromycin estolate	46
33.	Swertia longifolia Boiss.	Aerial parts		Paracetamol	47
34.	Telfairia occidentalis	Leaves	Aqueous and ethanolic extracts	Garlic	48
35.	Terminalia catappa L.	Leaves	Chloroform	CCl4	49
36.	Terminalia chebula Gertn	Fruit	Ethanolic	Rifampicin (RIF), isoniazid(INH), and pyrazinamide (PZA) (in combination)	50
37.	Teucrium stocksianum	-	Ethanolic	Paracetamol	51
38.	Thunbergia laurifolia		aqueous	Ethanol	52
39.	Trianthema portulacastrum L.		Ethanolic	Paracetamol and thioacetamide	53
40.	Trichilia emetica Vahl.	Root	aqueous	CCl4	54

References:

1.Tortora G.J. and Grabowski S.R.(2002) The digestive system (liver and gallbladder) In:Principles of Anatomy and Physiology, seventh edition, Harper Collins college publishers, New york, 24,page no. 792-795.

2.K.Sembulingam, Prema sembulingam (2004) Liver and Gallblader, Chapter 40 In:Essentials of Medical Physiology, Jaypee brothers medical publishers(p) ltd.,New Delhi 3^rd Edition, page no. 200-201

3.Ghadi P.S. (2000) Disorders of Liver Chapter 8 In: Pathophysiology for pharmacy career publications,Nashik,2^nd Edition, page no. 106-108, 125-130

4.Fry J.R., Bridges J.K.L. (1979) Rev.Biochem.Toxicol.,page no. 203-247

5.Grisham J.W.(1979) Int. Rev.Exp. Pathol.20, page no. 210-12

6.Homberg J.C.,  Abuat N., Hetmy-Khalills., Bloue M., Powlet J., Danan G., Benhamou J.P.(1985) Hepatology, page no. 722-727

7.Zimmerman M.D.and Heyman J., (1976) Function and integrity of the liver In: Clinical Diagnosis and Management by Laboratory Methods, 17^th Edition, page no. 217-50

8.Saraswat B., Visen PKS, Dayal R., Agarwal P.P., Patnaik G.K., (1996) protective action of ursolic acid against chemical induced hepatotoxicity in rats, Ind.J. Pharmacol., 28:page no. 232-239

9.Hardman J.G., Limbird L.E., (2001) Ehanol Chapter 18 In:Goodman & Gillman’s The Pharmacological basis of Therapeutics, McGraw Hill Medical Publishing Division, 10^th Edition, page no. 434.

10. Grahame-smith D.G., Azonson J.K., (1984) The drug therapy of gastro intestinal , hepatic and biliary disorders Chapter 23 In: Oxford Textbook of Clinical Pharmacology and Drug Therapy, Oxford University Press, Oxford.1^st Edition, page no. 383-385.

11. Sarada S., K. Madhanvankutty (1990) Secretion of small and large intestine Chapter 5 In:Textbook of Human Physiology, S Chand & Company Ltd., New Delhi , 4^th Edition page no. 182

12. Sood R., (1994) Enzymology Chapter 21 In:Medical Laboratory Technology- Methods and Interpretation, Jaypee Brothers medical Publishers(p) Ltd., New Delhi, 4^th edition, page no. 493-494, 504-505, 508-510, 513-514.

13. Harshmohan, (2002) The liver , biliary tract , and exocrine pancreas, In: Textbook of Pathology, Jaypee Brothers Medical Publishers (P) Ltd. New Delhi , 4^th Edition, page no. 22-24 and 569-630

14. Bhanwra S., Singh J. and Khosla P., (2002) Effects of Azadirachta indica leaf aqueous extract on paracetamol induced liver damage in rats, Ind. J. Physiol. Pharmacol., 44 (1), page no. 64-68

15. Porchezhian, E. and Ansari S.H. (2005), Hepatoprotective activity of Abutilon indicum on experimental liver damage in rats phytomedicine, 12, (1-2) page no. 62-64

16. Bhattacharya D., Pandit S., Jana U., Sen S., and Sur T.K. (2005) Hepatoprotective activity of Adhatoda vasica aqueous leaf extract on D-Galactosamine induced liver damage in rats. Fitoterapia.76(2), page no. 223

17. Rana A.C. and Avadhoot Y., (1991) Hepatoprotective effects of Andrographis paniculata against carbon tetra chloride –induced liver damage. Arch.Pharm.Res. 14(1) , page no. 93-5

18. Fleurentin, J., Hoefler, C., Lexa, A., Mortier, F. and Pelt J.M. (1986) Hepatoprotective properties of Crepis rueppellii and Anisotes trisulcus: Two traditional medicinal plants or Yemen J. Ethnopharmacol 16(1)  page no. 105-111

19. Singh, Anubha. And Handa S.S. (1995). Hepatoprotective activity of Apium graveolens and Hygrophylla auriculata against paracetamol and thioacetamide intoxication in rats. J.Ethnopharmacol.49(3) page no. 119-126

20. Bahar Ahmed., Tanver Alam., Manoj Varshney., Alam Khan.(2002) Hepatoprotective activity of two plants belonging to the Apiaceae and the Euphorbiaceae family. J. Ethnopharmacol. 79(3) page no. 313-316

21. Valcheva- Kuzmanova, S., Borisova, P., Galuska B., Krasnaliev I. , and Belcheva A., (2004) hepatoprotective effect of the natural fruit juice from Aronia melanocarpa on carbon tetrachloride induced acute liver damage in rats. Exp.Toxicol.Pathol 56(3) page no. 195-201

22. Anwar U.I., Hassan Gilani., and Khalid, Hussain, Janbaz (1195) Preventive and curative effect of Artemisia absinthium on Acetaminophen and CCl₄ induced hepatotoxicity. Gen Pharmacol. 26(2): page no. 309-315

23.Gilani A.H., Yaeesh S., Jamal Q., and Ghayur M.N.(2005) Hepatoprotective activity of aqueous methanol extract of artemisia vulgaris.Phytother.Res. 19 (2) : page no. 170-172

24. Shivashagari K.S., Ravikumar V., and Devaki T., (2004)Evaluation of the protective efficacy of Asteracantha longifolia on acetaminophen induced liver damage in rats. J.Med.Food.7(2) page no. 245-51

25. Chattopadhyay R.R., (2003) Possible mechanism of Hepatoprotective activity of Azadirachta indica leaf extract., Part II,  J. Ethnopharmacol.89(2-3): page no. 217-9

26. Citoglu, G.S., Dulger, H., Ugras S., and Sever B., (2004) hepatoprotective and anti-inflammatory activities of ballota glandulosissima. J.Ethnopharmacol.95(2-3): page no. 143-9

27. Singh B., Chandan B. and hepatoprotective activity of K., Prabhakar A., Taneja S.C., Singh J., and Qazi G.N., (2005)Chemistry an active fraction from Barleria prionitis Linn.in experimental animals . Phytother. Res. 19(5) : page no. 391-404

28. Jung S.H., Lee Y.S., Lim S.S., Lee S., Shin K.H., Kim Y.S. (2004) Antioxidant activities of isoflavones from the rhizome of Belamcanda chinensis on carbon tetra chloride induced hepatic injury in rats. Arch.Pharm.Res. 27(2) page no. 184-8

29. Agarwal M., Srivastava V., Saxena K.K., and Kumar (2006) A hepatoprotective activity of Beta vulgaris against carbon tetra chloride induced hepatic injury in rats.Fitoterapia. 77(2) page no.91-3

30. EI-Beshbishy, H.A., (2005) Hepatoprotective effect of green tea (Camellia sinensis) extract against tamoxifen-induced liver injury in rats.J. Biochem.Mol.Biol. 38(5) page no. 563-570

31. Jafri, M.A., Subhani M., Jalis, Javed, Kalim and Singh Surender.(1999) hepatoprotective activity of leaves of Cassia occidentalis against paracetamol and ethyl alcohol intoxication in rats.J.Ethnopharmacol 66(3) page no. 355-361

32. Mrouesh M., Saab Y., and Rizkallah R., (2004) hepatoprotective activity of Centaurium erythraea on acetaminophen induced hepatotoxicity in rats. Phytother.Res. 18(5): page no. 431-3

33. Mantena S.K., Mutalik S., Srinivasa H., Subramanian G.S., Prabhakar K.R., Reddy K.R., Srinivasan K.K., and Unnikrishnan M.K., (2005). Antiallergic , Antipyretic , hypoglycemicand hepatoprotective effect of aqueous extract of Coronopus didymus Linn. Biol.Pharm.Bull.28(3) page no. 468-72

34. Tian, Y.H., Kim H.C., Cui J.M., and Kim Y.C., (2005) Hepatoprotective constituents of Cudrania tricuspidata. Arch. Pharm. Res.28(1) page no.44-8.

35. Tasduq S.A. , Kaisar P., Gupta D.K., Kapahi B.K., Maheswari H.S., Jyotsna S., and Johri R.K., (2005) Protective effects of 50% hydroalcoholic fruit extract of Embellica officinallis against antituberculosis drugs induced liver toxicity. Phytother. Res.19 (3) page no. 193-197

36. Matsuda, H., Morikawa T., Xu F., Ninomiya K., and Yoshikawa M., (2004) New isoflavones and pterocarpane with hepatoprotective activity from the stem of Erycibe expansa Planta Med.70 (12) : page no. 120-9

37. Mohamed, A.F., Ali Hasan A.G., Hamamy M.I., and Abdel-Stattar E., (2005) Antioxidant and hepatoprotective effects of Eucalyptus Maculata. Med.Sci. Monit. 11(11) page no. 426-431

38. Suja S.R., Latha P.G., Pushpangadan P., and Rajesekharan S., (2004) Evaluation of hepatoprotective effects of Helminthostachys zeylanica (L) Hook against CCl₄ induced liver damage in wistar rats. J. Ethnopharmacol. 92(1) page no. 61-66

39. Manoj R., Bhandarkar, and Aqueel Khan., (2004) Antihepatotoxic effect of  Nymphaea stellata in rats. J. Ethnopharmacol.91(1) page no. 61-64

40. Ira Thabrew M., Christopher D., Gove, Robin D., Hughes, Ian G., Mcfarlane and Williams, Roger.(1995) protective effects of Osbeckia octandra against galactosamine and tert-butyl hydroperoxide induced hepatocyte damage. J. Ethnopharmacol. 49 (2-1) page no. 69-76

41. Devi K.P., Sreepriya, M., Balakrishna,K., and Devaki I., (2004) Protective effect of Premna tomentosa (L Verbenaceae) extract on membrane bound phosphatases and inorganic cations transport in acetaminophen induced hepatotoxicity rats. J. Ethnopharmacol 93(2-3) page no. 371-5

42. Asha V.V., Akhila S., Wills P.J., and Subramaniam A., (2004) Further studies on the antihepatotoxic activity of Phyllanthus maderaspatensis Linn. J. Ethnopharmacol. 92(1) Page no. 67-70

43.Roy C.K., Kamath J.V., Asad M., (2006) hepatoprotective activity of Psidium guajava Linn leaf extract . Indian J. Exp. Biol. 44(4) page no. 305-311

44.Jin Y.S., Heo S.I.,  Lee M.J., Rhee H.I., and Wang M.H., (2005)  Free radical scavenging and hepatoprotective actions of Quercus aliena acorn extract against CCl₄ induced liver.Free. Radic.Res. 39 (12) page no. 1351-1358

45.Hoefler C., Fleurentin  J., Mortier F., Pelt J.M., and Guillemain  J. (1987)  Comparative choleretic and hepatoprotective properties of young sprouts and total plants extracts of Rosmarinus officinallis in rats. J.Ethnopharmacol. 19 (2)  page no. 133-143

46.Pari L., and Uma A., (2003) Protective effects of Sesbania grandiflora against erythromycin  estolate induced hepatotoxicity Therapy  58 (5)  page no. 439-43

47.Hajimehdipoor H., Sadeghi Z., Elmi S.,  Elmi A., Ghazi-Khansari M., Amanzadeh Y., and Sadat – Ebrahimi S.E., (2006) protective effects of Swertia longifolia Boiss. And its active compound , swerchirin, on paracetamol induced hepatotoxicity in mice. J. Pharm. Pharmacol. 58(2) page no. 277-280

48.Oboth G., (2005) Hepatoprotective propertyof ethanolic and aqueous extract of fluted pumpkin (Telfairia occidentalis) leaves against garlic induced oxidative stress. J. Med. Food. 8(4) page no. 560-563

49. Tang X., Gao J., Wang Y., Fan Y.M., Xu L.Z., Zhao X.N., Xu Q., and Qian Z.M., (2006)  effective protection of Terminalia catappa L.leaves from damage induced by CCl₄ in liver mitochondria. J.Nutr.Biochem 17(3) page no. 177-182

50. Tasduq S.A., Singh K., Satti N.K.,  Gupta D.K.,  Suri K.A., and Johri R.K., (2006) Terminalia chebula(fruit)  prevents liver toxicity caused by sub chronic administration. Hum.Exp. Toxicol. 25(3)  page no. 111-118

51.Rasheed R.A.,  Ali B.H., and Bashir A.K.,  (1995)  Effect of Teucrium stocksianum,on paracetamol induced hepatotoxicity in Mice.Gen. Pharmacol. 26(2) page no. 297-301

52.Pramyothin P., Chirdchupunsare H., Rungsipipat A., and Chaichantipyuth C., (2005) hepatoprotective activity of thunbergia laurifolia Linn. extract in rats treated with ethanol :in vitro and in vivo studies. J. Ethnopharmacol. 102 (3)  page no. 408-411

53. Kumar G., Banu G.S., Pappa P.V., Sundrarajan M., and Pandian M.R., (2004) hepatoprotective activity of Trainthema portulacastrum L. against paracetamol and thioaacetamide intoxication in albino rats. J.Ethnopharmacol. 92(1) page no. 37-40

54.Germano M.P., Angelo D., Pasquale R., and Bisignano G., (2005) hepatoprotective  and antibacterial effects of extract from Trichilia emetica vahl.(Meliaceae) J.Ethnopharmacol. 4:96(1-2) page no.227-32

About Authors:

Sumeet Dwivedi & Shanti Bhushan Mishra

Sumeet Dwivedi
Vinayaka Missions College of Pharmacy, Salem (T.N.)

Shanti Bhushan Mishra
Vinayaka Missions College of Pharmacy, Salem (T.N.)