Effect of Terminalia catappa on lipid profile in transplanted fibrosarcoma in rats.

To evaluate the effect of an antitumor activity of Terminalia catappa on lipid lowering activity in transplanted fibrosarcoma in Wistar albino rats. Methylcholantherene-induced fibrosarcoma was transplanted in rats. After 30(th) day when tumor became palpable, started the treatment of ethanolic extract of Terminalia catappa by orally (250 and 500 mg/kg) for a period of 20 days. The blood sample was collected on 21(st) day, and the liver and the kidney were also removed for studying the lipid profile in serum and the tissues. The levels of total cholesterol, triglycerides and very low density lipoprotein (VLDL) were markedly elevated and high density lipoprotein (HDL) was markedly decreased in the serum of tumor bearing rats. Significant alterations were also observed in the lipid profile of liver and kidney. These changes were significantly reversed in Terminalia catappa (500 mg/kg) treated animals. The reversal of altered lipid levels to normal values in rats with experimentally induced tumor was showed antitumor activity by Terminalia catappa.

Introduction

A fibrosarcoma is a malignant (cancerous) tumor that originates in the connective fibrous tissue found at the ends of bones of the arms or legs, and then spreads to other surrounding soft tissues. Soft tissues include fat, muscles, tendons (bands of fiber that connect bones to muscle) nerves, joint tissue, blood vessels and other fibrous tissue. It most commonly affects either a lower legs or arms.[1]

Chemotherapy is a major treatment for cancer, and some of the plants like Catharanthus roseus, Podophyllum peltatum, Podophyllum emodii, Taxus brevifolia, Ochrosia elliptica and Campototheca acuminate have provide active principles used to control advanced stages of malignancies.[2] Most of the chemotherapeutic agents have been reported to exhibit several normal tissue toxicity, accompanied by undesirable side effects. Further, many of the potent antineoplastic drugs are highly expensive, mutagenic, carcinogenic and teratogenic.[3]

The leaves of the plant Terminalia catappa have been used as a folk medicine for treating dermatitis, hepatitis in India and in Philippines. Earlier studies showed that Terminalia catappa possess antioxidative, anti-inflammatory, and hepatoprotective activity. Leaves of Terminalia catappa possess anti – cancer, antioxidant as well as anti-clastogenic characteristics.[45] Some flavonoids and hydrolyzable tannins have been identified in the Terminalia catap,[6] and earlier were reported, and it has shown that silibinin, a polyphenolic flavonoid isolated from milk thistle, inhibits the lung cancer metastasis.[7]

However, the literature survey offered no scientific claim on antitumor activity of Terminalia catappa against transplanted fibrosarcoma in rats. Therefore, the present study was planned to evaluate the antitumor activity of Terminalia catappa against effect on lipid profile in transplanted fibrosarcoma in rats.

Materials and Methods

Plant and Extraction

Leaves of plant Terminalia catappa were collected in the garden and authenticated by Dr. Jawahar Raveendran, Botanist, Bangalore, Karnataka, India. The leaves were shade–dried and made cores powdered. The powder was then packed into Soxhlet apparatus and subjected to hot continuous percolation using ethanol (95% v/v) as a solvent. The extract was concentrated under vacuum evaporator and stored in airtight container at 4°C in refrigerator.

Animal

Wistar albino rats of either sex (150 g – 200 g) were obtained from the National Institute of Mental Health and Neuro Science (NIMHANS), Bangalore. Rats were housed in polypropylene cages at controlled environment (temperature 25±2°C and 12 h dark/light cycle) and provided standard mice pellets and, water was allowed ad libitum. Experimental protocols were approved by our Institutional Animal Ethical Committee (Protocol No: 07/P’cology/09–10) and were used for the study.

Induction of fibrosarcoma

Fibrosarcoma was induced in rats by the method of Nagarajan and Sankaran.[8] Methylcholantherene-induced fibrosarcomas maintained in rats were removed and minced in saline and prepared as a 10% suspension by homogenizing in a tissue homogenizer. 0.2 ml of this was injected into the inguinal region of the experimental animals. After 30 days, when the tumor developed into a palpable stage, the treatment was started. 2 doses of ethanolic extract of Terminalia catappa (250 and 500 mg/kg) were selected for treatment.

The animals were divided into 5 groups of 6 animals each. The first group consisted of normal rats while the second group had tumor bearing control animals, which received only the vehicle. The third and fourth groups (tumor bearing) were administered 250 and 500 mg/kg, orally of Terminalia catappa and fifth group received 5–Fluorouracil (20 mg/kg, orally), respectively, continuously for 20 days.

Estimation of lipids

On day 21, 24 h after the last dose blood was collected by cardiac puncture prior to sacrifice. The liver and the kidney were removed quickly, washed with ice-cold saline and preserved. Estimation of lipid parameters viz. total cholesterol, triglycerides, HDL, and VLDL in serum, liver, and kidney were carried out by using the biochemical kits (Span diagnostic Ltd, Mumbai, India).

Statistical Analysis

The statistical significance was assessed using one-way analysis of variance followed by Dennett's test. The values are expressed as mean ± SEM, and P<0.05 were considered to be statistically significant.

Results

The various parameters in the serum such as total cholesterol, triglycerides, and VLDL were found to be significantly elevated and HDL were significantly decreased in tumor-bearing rats [Table 1]. Terminalia catappa (500 mg/ kg) treatment restored these parameters to normal levels. In liver as well as in kidney, a significant reduction in the total cholesterol, triglycerides, HDL, and VLDL were observed in the tumor-bearing rats [Table 2]. Terminalia catappa (500 mg/ kg) restored all these values to normal levels while there was only a partial restoration of these values with the lower dose (250 mg/ kg). Terminalia catappa treatment was not statistically alters the HDL level in kidney. The alterations in the lipid parameters observed in the kidney were similar to those in the liver.

Table 1

Effect of ethanolic extract of Terminalia catappa on lipid levels in serum of fibrosarcoma bearing rats

Table 2

Effect of ethanolic extract of Terminalia catappa on lipid levels in liver and kidney of fibrosarcoma bearing rats

Discussion

The increased level of total cholesterol and triglycerides in fibrosarcoma–bearing control group may be explicated by reducing activities of fat splitting enzymes such as, lecithin: Cholesterol acetyltransferase (LCAT) and lipoprotein lipase. LCAT is responsible for an esterification of free cholesterol in plasma, and it indirectly controls the levels of free cholesterol in various cells and tissues. Lipoprotein lipase is the clearing factor for triglyceride in plasma and cleaves triglycerides into free fatty acids and glycerol.[9]

The increased levels of triglycerides observed in fibrosarcoma–bearing rats may be due to the increased synthesis of VLDL cholesterol. The decreased level of HDL cholesterol observed in untreated fibrosarcoma bearing rats may be explained by the parallel decreases in LDL cholesterol. Since, the reduction in HDL cholesterol is mostly compensated by an increment in LDL cholesterol, and vice versa.[10] The increased synthesis of very low density lipoprotein-cholesterol observed in fibrosarcoma–bearing control could have led to the increased triglyceride levels in fibrosarcoma–bearing animals. Finally, excessive lipid peroxides formed in fibrosarcoma condition may lead to hyper–lipidemia.[11]

Excessive rates of lipid peroxidation may be root of the hyperlipidemia, found in many cancer patients.[12] Terminalia catappa may have hypocholesterolemic effect, probably by an increase in the activity of cholesterol – 7-hydroxylase which increase the cholesterol.

In the tumor–bearing animals, increased lipolytic activity was reported, associated with hyper lipidemia.[13] The hyperlipidemic state was found to correlate with tumor burden and was reversible on tumor removal remission.

In the present study, a significant depletion of triglyceride, total cholesterol, HDL, VLDL from liver and kidney of the animals was observed, indicating an increased lipolytic activity in tumor–bearing animals. Correspondingly, the elevated levels of these lipids were observed in serum. The treatment of Terminalia catappa significantly attenuated these alterations of lipid levels in tissue as well as in serum. The depletion of fat stores associated with tumor growth indicates high energy requirement and hence an increased lipolytic activity.[14] The normalization of lipid level in liver and kidney tissues and serum upon Terminalia catappa treatment may be due to an enhanced lipogenesis or due to decrease in lipolysis, or both. These changes were significantly reversed in Terminalia catappa treated animals at oral dose of 500 mg/kg.

The results indicate that ethanolic extract of Terminalia catappa exhibited significant reversal of altered lipid levels near to normal values in rats with experimentally-induced fibrosarcoma.