Received date: 25/08/2014; Revised date: 15/09/2014; Accepted date: 26/09/2014
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Tiger nuts (Cyperus esculentus) are under-utilized due to lack of information on their nutritional potential. A lot of people eat the tiger nut without knowing the nutritional benefits and products that can be obtained from it. Tiger nut milk is used as a liver tonic in China and some other countries. The purpose of this study therefore was to investigate the protective effects of Tiger nut against a dose of Carbon-Tetrachloride (CC14) induced liver damage in experimental rats. The induction of liver damage was done by intraperitoneal administration of CC14 (0.5m1/kg body weight in olive oil). This led to significant increases in the levels of L-aspartate aminotransferase (AST), L-alanine transferase (ALT), alkaline phosphatase (ALP) and lipid peroxides in the CC14 intoxicated rats. Pretreatment with varied concentrations of Tiger nut diets (1%, 5% and 10%) and vitamin E (9 %,) for 21 days prior to CC14 administration resulted in significant decreases in liver marker enzymes and lipid peroxides. The results of this study therefore suggest that Tiger nut may be acting as a natural antioxidant that prevents hepatic oxidative stress induced by CC14.
Hepatoprotective, Carbon tetrachloride, Tiger Nut, Liver marker enzymes, Lipid peroxides
Tiger nut (Cyperus esculentus) isn emergent grass- like plant belonging to the sedge family . It is widely distributed in the temperature zones within South Europes its probable origin,nd has become naturalized in Ghana, Nigeriand Sierra Leone . Tiger nuts have long been recognized for their health benefitss they have high content of soluble glucosend oleiccid,long with high energy content (starch, fats, sugarsnd proteins). Theyre rich in minerals suchs phosphorousnd potassium, calcium, magnesiumnd iron necessary for bones, tissue repair, muscles, the blood streamnd for body growthnd developmentnd rich in vitamins End C [3,4].
Therere mainly three varieties namely: black, brownnd yellow,nd only yellownd brownre readilyvailable in the Nigerian markets. The yellow variety is preferred toll other varieties because of its inherent properties like its bigger size,ttractive colournd fleshier body. The yellow varietylso yields more milk, contains lower fatnd higher proteinnd lessnti-nutritional factors especially polyphenols . Sugar-free tiger nut milk is suitable for diabetic peoplendlso helps in weight control , due to its content of carbohydrates with base of sucrosend starch (without glucose),nd its high content ofrginine, which liberates the hormone that produces insulin . It is recommended for those who suffer from indigestion, flatulencend diarrhoea because it provides digestive enzymes like the catalase, lipasendmylase . The high content of oleiccid has positive effect on cholesterol, thereby preventing heartttacks, thrombosisndctivates blood content of soluble glucose. Tiger nut reduces the risk of colon cancer. It prevents constipation. Tiger nut contains good quantity of vitamin B1, whichssists in balancing the central nervous systemnd helps to encourage the body todapt to stress . The milk supplies the body with enough quantity of Vitamin E, essential for fertility in both mennd women.
In China, tiger nut milk is useds liver tonic, heart stimulant, drank to heal serious stomach pain, to promote normal menstruation, to heal mouthnd gum ulcers, used inyurvedic medicinesnd is powerfulphrodisiac (sexual stimulant).The black species of the tiger nut isn excellent medicine for breast lumpsnd cancer. The tubers have relatively high totalntioxidant capacity, because they contain considerablemounts of water-soluble flavonoid glycosides .
In Nigeria, tiger nut isvailable in fresh, semi-driednd dried form in the markets where it is sold locallynd consumed even uncooked. These nutsre under-utilized due to lack of information on their nutritional potential . lot of people eat the tiger nut without knowing the nutritional benefitsnd products that can be obtained from it like tiger nut oilnd milk. The purpose of this study was to investigate the hepatoprotective potential of the tiger nut that is completely unexploited in Nigeria.
Tiger nuts (Cyperus esculentus) purchased from local market in Oyo, Oyo State, Nigeria were slicednd dried in their for 5 days. The dried, sliced seeds were ground into flour withn electric blender (Model MX – 795N-National)
Malelbino rats of the Wistar strain (150g-180g) were obtained from the University of Ibadannimal house.nimals were maintained under standard environmental condition (28-30OC, 60-70 % relative humidity, 12-h dark / light cycle) in stainless steel cages with freeccess to standard laboratorynimal diet (Vital finisher)nd drinking water. They were left tocclimatize to laboratory conditions for 7 days prior to commencement of the experiment.
The rats were divided into six groups with each group comprising fivenimals. Rats in groups 1nd 2 received the pelleted dietnd water, while those in groups 3, 4nd 5 were fed with diet formulated with the flour of Cyperus esculentusnd rat pelletss follows:
Group 3: 1% flour of Cyperus esculentus;
Group 4: 5% flour of Cyperus esculentus
Group 5: 10% flour of Cyperus esculentus
Also,nimals in group 6 received diet compounded with vitamin End rat pellets (9% vitamin E).
All the rats in the various groups received their respective dietsnd waterd libitum for 21 days. On the 22nd day of the experiment, CCl4 (0.5ml/kg body weight in 0.5 olive oil) wasdministered intraperitoneally to rats in groups 2, 3, 4, 5nd 6. Thenimals werellowed to fast for 24 hoursfter which they werenaesthetized in chloroform saturated chamber .
Blood samples were obtained by cardiac puncture from each rat by means of 5ml hypodermic syringend needle. The blood samples were introduced into clean, dry bottles withoutnticoagulants for serum separation. The bottlesnd its contents were centrifugedt 5000g for 10 minutes.
Serum was collected into clean, dry sample container. The serum levels of L-aspartateminotransferase (AST), L-alanine transferase (ALT)ndlkaline phosphatase (ALP) were measured spectrophotometricallys described by Verly . The liver was excised, washed in ice-cold saline,nd homogenizedt 0.1 M Tris-HC1 buffer (pH 7.4; 40C) in homogenizert 600 rpm for 4 minutes using mortarnd pestle . The liver homogenate was employed inssaying thectivities of the lipid peroxidess described by Hunter et.l.  and modified by Gutteridgend Wilkins .
The mean values of the various groups were compared usingnalysis of variance (ANOVA)nd the level of significance was sett p ≤ 0.05.
The effects of pretreatment with Tiger nutnd vitamin E, 21 days prior to CCl4dministration on liver enzymesnd lipid peroxides in rats is shown in Table 1, figures 1 and 2.
Table 1: Effects of Varied Levels of Cyperus esculentus and Vitamin E on Liver Enzymes of Rats Administered CCl4
Rats in Group 2 that received single dose of CCl4 showed marked elevation of the liver enzymes when compared with those of the group 1 (control) rats. However, the pretreated groups 3, 4, 5nd 6 rats showed significant decline in the levels ofST,LTndLP when compared with group 2 rats that received CCl4lone.
Increased levels of lipid peroxides were recorded in the liver tissue of group 2 ratss shown in figure 2. Thectivities of the peroxides decreased with increase in themount of the Cyperus esculentus in the feed formula. This is confirmed in the values obtained in rats in groups 3, 4,nd 5. Similarly, rats in group 6 recorded malondialdehyde values close to those of group 5nd 1 (control) rats.
Administration of CCl4 in this study resulted in significant hepatic damages indicated by the elevation in the levels of liver marker enzymes (AST,LT,LP). This indicated that CCl4 intoxication compromised the integrity of the hepatic cell membranes .The elevated level of the enzymes obtained in this study validates those of Nishigaki, et.l. , Raja, et.l.  nd Shafaq et.l.  who reported elevated levels in the serum content of hepatic enzymes in ratsdministered with CC14.
The evaluation of the preventivection in liver damage induced by CCl4 has been widely used for hepatoprotective drug screening. CCl4 is widely used experimental hepatotoxicant which requires metabolicctivation by the liver cytochrome P-450 enzymes to form highly reactive toxic metabolites suchs trichloromethyl radical (CCl3.)nd peroxy trichloromethyl radical (CCl3OO.). Both trichloromethylnd its peroxy radical (CCl3-OO·)re capable of covalently binding to proteins or lipids of cell membranesnd organelles,bstracting hydrogentoms from polyunsaturated fattycid (PUFA), initiating lipid peroxidation thus causing damage to cell membrane, disturbing Ca2+ homeostasis, changing enzymectivities,nd finally inducing hepatic injury or necrosis [20,21].
Since thebove mechanism is suggestive of the process of oxidative stress, it is true, therefore, thatny natural product withntioxidant property will prevent or reverse lipid peroxidation; including cell membrane damage. Previous study by Temple etl.  that tiger nuts have relatively high totalntioxidant capacity, because they contain considerablemounts of water-soluble flavonoid glycosidesnd the fact that tiger nut milk is useds liver tonic in China prompted this study.
The results of this study show that pretreatment of rats 21 days preceding CC14dministration caused marked decline in the levels of hepatospecific serum enzymes. This suggests that Tiger nuts (Cyperus esculentus) may be protectivegainst CC14-induced liver damage in rats. This was established by comparativenalysis of the results obtained in rats pretreated with Cyperus esculentusnd vitamin E.
Malodialdehyde (MDA) is product of lipid peroxidation .n increase in the liver MDA levels is signal of elevated level of lipid peroxidation . Extensive lipid peroxidation leads to disorganization of membrane by peroxidation of unsaturated fattycids whichlsolters the ratio of poly-unsaturated to other fattycids. This would lead to decrease in the membrane fluiditynd the death of cells.
The results of the present study indicate that Tiger nuts (Cyperus esculentus ) exhibited potential hepatoprotectivectivitygainst carbon tetrachloride induced hepatotoxicitynd validate the traditional use of this nuts liver tonic. The significant decrease in the levels of lipid peroxides recorded in rats pretreated with Cyperus esculentus suggests that the nuts may possess the naturalntioxidants necessary for protectiongainst free radical damage induced by CC14 in rat liver. The Tiger nut, though under-utilized, is therefore still good food snack forll. Further studiesre required to isolatend characterize thective principles, whichre responsible for the hepatoprotective efficacy of this valuable medicinal seed.