ANTIOXIDANT AND ANTICANCER ACTIVITIES OF ETHANOLIC EXTRACT OF FICUS GLOMERATA ROXB. IN DMBA INDUCED RATS

ANTIOXIDANT AND ANTICANCER ACTIVITIES OF ETHANOLIC EXTRACT OF FICUS GLOMERATA ROXB. IN DMBA INDUCED RATS

V. Dhana Rangesh Kumar*¹, G. Jayanthi ², K. Gurusamy ¹ and S. Gowri ¹

Department of Biochemistry, Dr. N.G. P Arts and Science College ¹, Coimbatore, Tamil Nadu, India

Department of Biochemistry, Govt. Arts and Science College for Women’s ², Krishnagiri, Tamil Nadu, India

ABSTRACT:The present study was designed to evaluate the antioxidant and anticancer activities of the ethanolic leaf extract of Ficus glomerata Roxb. on the basis of enzymatic and non-enzymatic antioxidants, xenobiotic enzymes and histopathological parameters in 7, 12- dimethylbenz(a)anthracene (DMBA) induced mammary carcinoma in rats. F. glomerata is large evergreen tree, found all over India and South East Asia. DMBA at a dose of 20mg/kg body weight (gastric intubation) significantly reduce the enzymatic antioxidant  such as superoxide dismutase (SOD), catalase (CAT), glutathione-s-transferase (GST), glutathione peroxidase (GPX), glutathione reductase (GR), glucose-6-phosphate-dehydrogenase (G6PD) and non-enzymatic antioxidant like vitamin-C, vitamin-E and total reduced glutathione (TRG) and lipid peroxidation (LPO) in group II rats. A significant increase in xenobiotic enzymes like cytochrome P₄₅₀ and cytochrome b₅, in DMBA induced groups were observed. Treatment with ethanolic leaf extract of F. glomerata (150mg/kg body weight, orally) in group III rats were observed all these above mentioned parameters were reverted to near normal level when compared to control rats. Finally, we concluded that the F. glomerata leaf extract exerts equipotent anticancer and antioxidant activities in the experimental model of DMBA induced mammary carcinoma in rats.

Ficus glomerata, Antioxidant, Anticancer , 7, 12-dimethylbenz(a)anthracene (DMBA)

INTRODUCTION:Cancer is one of the non-communicable diseases and a public health problem in the world. Cancer is a second major cause of death in the world.

More than 70% of all death due to cancer occurred in developing countries. One of main types of cancer is breast cancer in the world ¹.

The role of interactions between genes and environment in carcinogenesis is clearly demonstrated by phase I and II enzymes that constitute the central armamentarium against toxic chemicals and carcinogens. Several environmental carcinogens that are not chemically active undergo metabolic activation.

Cytochrome P₄₅₀, a family of phase I hemoproteins, represents a major adaptive response against chemical challenge from the environment and catalyzes the activation of various procarcinogens to ultimate carcinogens. The ultimate carcinogens in turn interact with DNA, resulting in chromosomal abnormalities and mutation ¹ is in key growth regulatory genes that eventually culminate in neoplastic transformation. Phase II enzymes detoxify pro- and ultimate forms of chemical carcinogens, thereby decreasing DNA damage.² It follows that control of environmentally induced cancers can be achieved by decreasing the rate of DNA damage through modulation of phase I and II biotransformation enzymes.

Mammary glands of several rat strains, mainly Sprague-Dawley and Wistar-Furth, are susceptible to transformation induced by chemical carcinogens and the two most widely used active chemical inductors of mammary carcinogenesis are 7, 12- dimethylbenz(a)anthracene (DMBA) and N-methylnitrosurea ^{4, 5}_. 

Several markers have been developed to biomonitor chemoprevention. These are based onthe fact that chemopreventive agents can exert their anticarcinogenic effects by one or a combination of the following mechanisms: inhibiting formation of reactive carcinogenic metabolizes, induction of enzymes that detoxify carcinogens, scavenging reactive oxygen species, influencing apoptosis and inhibiting cell proliferation ^{6, 7}.The tripeptide glutathione, a physiologically important nucleophileand the enzymes glutathione peroxidase (GPx), glutathione S-transferase (GST), which utilize reduced glutathione (GSH) as substratehave assumed significance as biomarkers of chemoprevention owing to their antioxidant anddetoxification properties ^{8, 9, 10}.

Many plants have antioxidant properties which protect our cells from oxidative damage, which is further linked to many diseases. These antioxidant properties of plants are due to various phytochemicals present in the plant.¹¹ India has a rich heritage of medicinal plants, many of which have been explored for the various bioactivities since ages. However, The radio protective potential of plants have been hardly explored, though a large number of compounds were isolated from various plant sources have been shown to possess antioxidant properties ^{12, 13}.

One such plant is Ficus glomerata which has been used in traditional system of medicine for treating liver diseases, anemia and gastrointestinal disorders like constipation, diarrhoea, piles, asthma, leprosy and other ailments ¹⁴.

The fruits of Ficus glomerata, locally known as Gularhave been used since olden times in the ethnomedicine for many varied medicinal purposes including as a remedy of diabetes mellitus ¹⁵.In addition, this plant is considered to possess tonic, expectorant, emollient, stomachic and carminative properties ¹⁶. The sap extracted from trunk of the tree is also considered curative in diabetes. Moreover, the powdered seeds mixed with pure bee-honey are prescribed to the diabetics in the folklore medicine ¹⁷.

The present research program was aimed to investigate anticancer and antioxidant activities of leaf extract of Ficus glomerata inDMBA induced mammary carcinoma rats.

MATERIALS AND METHODS:

Chemicals: DMBA (7, 12 Dimethylbenz(a) anthracene) was purchased from sigma chemical company St. Louis, MO, USA. All other chemicals used in this study were of analytical grade which were brought from Himedia laboratories private ltd., Mumbai, India.

Plant: Ficus glomerata leaves were collected from the trees located in and around Coimbatore. The leaf samples were authenticated by Dr.V.S.Ramachandran, Professor, Department of Botany, Bharathiar University, Coimbatore- 46.

Preparation of the extract: F. glomerata leaves were shade dried and powdered. 10gram of this powder was extracted with 250ml of ethanol in a soxhlet apparatus. The obtained residues were vaccum dried and used for the study.

Experimental animals: Female Sprague dawley rats (180-200g) obtained from the small animal breeding station, Mannuthy, Thrissur, Kerala, India. The animals were housed and maintained in clean polypropylene cages. The animals were fed with standard pellet diet (M/s.Hindustan lever ltd, Mumbai, India) and water ad libitum.

The experimental protocol was carried out according to the guidelines of the committee for the purpose of control and supervision of experiments on animals (CPCSEA), India and approved by the animal ethical committee.

Experimental design: A total of 30 rats were used. The animals were divided into five groups of six animals each as follows.

• Group I served as control rats receiving olive oil, a vehicle alone.
• Group II rats were induced with a single dose of DMBA (20mg/rat, dissolved in olive oil) by oral gavage at the first day of experimental period.
• Groups III rats received F. glomerata extract (150 mg/kg b.wt.) orally for 14 days after 90 days of DMBA induction.
• Group IV received Tamoxifen (20 mg/kg b.wt.) orally for 14 days after 90 days of DMBA induction.
• Group V rats received   F. glomerata extract alone (150 mg/kg b.wt.)  Orally for 14 days.

At the end of the experimental period (i.e. on the 15^thday) all animals were euthanized and the liver, kidney, mammary tissues were excised immediately and rinsed with ice cold saline, dried with blotting paper, weighed, cut into pieces and 1 gram of each sample (liver, kidney, mammary tissue) was homogenized with 0.25M sucrose, 1mM Tris HCL and 1mM EDTA, (pH 7.2-7.4) using a motorized glass-Teflon homogenizer to get a 10% homogenate.

The 10% homogenate was centrifuged at 600x g for 5 minutes to remove the nuclear fraction and broken cell debris and then supernatant was collected. That supernatant was centrifuged at 1200x g for 10 minutes to sediment the mitochondrial fraction. Mitochondrial pellet was finally suspended in 0.25M sucrose solution. All operations were performed at 4°C. The mitochondrial fraction was used for the following biochemical studies.

Phase I mitochondrial xenobiotic enzymes: The mitochondrial fraction of liver, kidney, mammary tissue homogenates were used for assaying cytochrome P₄₅₀ reductase ¹⁸ and Cytochrome b₅ reductase ¹⁹.

Phase II Antioxidant activities in mitochondrial fraction: The mitochondrial fraction of liver, kidney, mammary homogenate were used for assaying superoxide dismutase (SOD) ²⁰, catalase (CAT) ²¹, glutathione peroxidase (GPx) ²², glutathione reductase (GR) ²³, glutathione-S-transferase (GST) ²⁴, glucose-6-phosphate dehydrogenase (G6PD) ²⁵, total reduced glutathione (GSH) ²⁶, vitamin-C ²⁷, vitamin-E ²⁸ and lipid peroxidation (LPO) ²⁹.

Statistical analysis: The values were expressed as mean ± SD.Data were analyzed for the statistical significance by one way analysis of variance (ANOVA) followed by the group means were compared with  Dunnett’s multiple comparison test using a statistical software package SPSS version 10 and value of P<0.05 was considered to indicate a significant difference between the groups.

RESULTS AND DISCUSSION:

Phase I mitochondrial xenobiotic enzymes: The activities of mitochondrial xenobiotic enzymes such as cytochrome P₄₅₀ reductase and cytochrome b₅ reductase in liver, kidney and mammary tissue of control and experimental rats were presented in tables 1, 2 and 3.

TABLE 1: EFFECT OF FICUS GLOMERATA ONPHASE I XENOBIOTIC ENZYMES IN LIVER MITOCHONDRIAL FRACTION OF CONTROL AND EXPERIMENTAL RATS

TABLE 2: EFFECT OF FICUS GLOMERATA ON PHASE I XENOBIOTIC ENZYMES IN KIDNEY MITOCHONDRIAL FRACTION OF CONTROL AND EXPERIMENTAL RATS

TABLE 3: EFFECT OF FICUS GLOMERATA ON PHASE I XENOBIOTIC ENZYMES IN MAMMARY TISSUE MITOCHONDRIAL FRACTION OF CONTROL AND EXPERIMENTAL RATS

Units: Cytochrome P₄₅₀ reductase – μmol of NADPH oxidised/min/mg protein, Cytochrome b₅ reductase –μmol of NADH oxidised FeCN/min/mg protein; Values are mean ± SD of six observations. Comparisons are made between: a –Group I vs Group II & V; b – Group II vs Group III & IV; c – Group III vs Group IV. Statistical significance:  a,b,c significant at p<0.05, ns-not significant.

The activities of xenobiotic enzymes like cytochrome P₄₅₀ reductase and cytochrome b₅ reductase in liver, kidney and mammary tissue were significantly (p<0.05) increased in DMBA induced (Group II) rats when compared to control (Group I) rats. F. glomerata leaf extract treated (Group III) rats showed significant (p<0.05) decrease in the levels of cytochrome P₄₅₀ reductase and cytochrome b₅ reductase when compared with DMBA induced rats. Tamoxifen administered (Group IV) rats also showed the above mentioned enzyme activities were near normal level when compared to control rats. Plant extract alone administered rats (Group V) did not show any significant changes when compared to control rats.

Hence, the effect of F. glomerata on phase I enzyme might be due to its flavonoid content that decrease cytochrome P₄₅₀ activity either by increasing V_max or decreasing K_m for microsomal monoxygenase and enhancing the interaction with cytochrome P₄₅₀ binding to the catalytic site. F. glomerata actively reduces the activity of cytochrome b₅ reductase in the cancer bearing animals, indicating its overall effect on phase I enzymes mediated by its flavonoids content ³⁰.

Phase II enzymic and non enzymic antioxidant status in mitochondrial fraction: Tables 4, 5 and 6 shows the activities of mitochondrial enzymic antioxidants like SOD, CAT, GPX, GR, GST and G6PD and levels of non-enzymic antioxidants like GSH, Vitamins C and E in mitochondrial fractions of liver, kidney and mammary gland of control and experimental rats. The antioxidant status (both enzymic and non-enzymic) was found to be significantly lowered (p < 0.05) in mammary carcinoma bearing rats when compared with normal control rats. All these alterations were reverted to nearly control values on the administration of F. glomerata extract in Groups III animals. In F. glomerata extract treatment, the antioxidant levels were further increased when compared with standard Tamoxifen treated rats.

TABLE 4: EFFECT OF FICUS GLOMERATA ON THE LEVELS OF MITOCHONDRIAL ANTIOXIDANT STATUS IN LIVER

TABLE 5: EFFECT OF FICUS GLOMERATA ON THE LEVELS OF MITOCHONDRIAL ANTIOXIDANT STATUS IN KIDNEY

TABLE 6: EFFECT OF FICUS GLOMERATA ON THE LEVELS OF MITOCHONDRIAL ANTIOXIDANT STATUS IN MAMMARY GLAND

Units: SOD - Units/mg protein, Catalase - μmoles H₂O₂ decomposed /min/mg protein, Gpx - μgrams glutathione utilized /min/mg protein, GR - μmoles NADPH oxidized /min/mg protein, G-S-T - μmoles CDNB conjugate formed /min/mg protein,

G-6-PO₄ DEHROGENASE – Units/mg protein, TRG – μmoles/g tissue, Vitamin-C – mg/g tissue, Vitamin-E – mg/g tissue

Values are mean ± SD of six observations. Comparisons are made between: a –Group I vs Group II & V; b – Group II vs Group III & IV; c – Group III vs Group IV. Statistical significance:  a, b, c significant at p<0.05, ns-not significant.

Reactive oxygen species (ROS) that are formed during the metabolism of DMBA can diffuse from the site of generation to other targets within the cell or even propagate the injury outside to intact cells. The liver is especially vulnerable to such ROS-induced damage although endowed with a rich supply of antioxidants. Thus, ROS-induced lipid and protein oxidation with compromised antioxidant defenses ^{31, 32}.

Low levels of GSH and reduced activities of GPx, SOD and CAT seen in mammary tumors and liver of DMBA treated animals in this study can cause accumulation of superoxide anion and H₂O₂ with deleterious consequences including oxidation of critical –SH groups and conformational changes in functional proteins leading to oxidative stress.

Table 7 represents the level of LPO in liver, kidney and mammary gland mitochondrial fraction of control and experimental rats. A significant (p < 0.05) increased LPO were observed in mammary carcinoma bearing rats. Tamoxifen and F.glomerata treatment resulted in a free radical quenching effect thereby, preventing the peroxidation of lipids significantly (p < 0.05).

TABLE 7: EFFECT OF FICUS GLOMERATA OF MITOCHONDRIAL LIPID PEROXIDATION IN LIVER, KIDNEY AND MAMMARY GLAND

Units: LPO – nmoles of MDA formed/dl. Values are mean ± SD of six observations. Comparisons are made between: a –Group I vs Group II & V; b – Group II vs Group III & IV; c – Group III vs Group IV. Statistical significance:  a,b,c significant at p<0.05, ns-not significant.

Apart from the enzymic antioxidants, non-enzymic antioxidants such as GSH, Vitamins C and E play an excellent role in protecting the cells from oxidative stress. Mitochondrial GSH plays a critical role in maintaining cell viability through the regulation of mitochondrial inner membrane permeability by maintaining sulfhydryl groups in the reduced state ³³. The levels of these antioxidants were significantly lowered in cancer condition. This observation supports our finding where we have observed a decline in GSH levels with an increase in oxidative stress as evidenced by increased mitochondrial LPO. The GSH level was restored to near normalcy on combinatorial therapy, which may be due to the antioxidant activity of riboflavin to regenerate the glutathione pool by reduction of oxidized glutathione. α -Tocopherol is a powerful chain breaking antioxidant and free radical scavenger which inhibits peroxidation of mitochondrial membrane lipids. Vitamin E is one of the exclusive antioxidant that protects against carcinogenesis and tumor growth. Vitamin C acts as an antioxidant to protect Vitamin E within cell membranes.

Being water-soluble, vitamin C cannot directly protect the fat-soluble cell membranes. However, it does seem to protect any fat-soluble components coming into contact with the water-soluble phase. The observed decrease in the level of vitamins C and E in mammary carcinoma bearing rats may be due to the excessive utilization of these antioxidants for quenching enormous free radicals generated in cancer condition. Oral administration of combinatorial therapy restored the vitamins C and E levels to near normalcy.

F. glomerata having strong antioxidant that enhances the benefits of other antioxidants, such as vitamins C and E ³⁴. F. glomerata leaf extract significantly reduced the incidence of mammary tumors. F. glomerata leaf extract at a dose of 150 mg/kg bw were more effective in chemoprevention as well as in modulating phase I and phase II enzyme activities and oxidant–antioxidant status, inhibiting cell proliferation and inducing apoptosis

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    How to cite this article:

    Kumar VDR, Jayanthi D, Gurusamy K and Gowri S: Antioxidant and Anticancer activities of Ethanolic extract of Ficus glomerata Roxb. in DMBA induced rats. Int J Pharm Sci Res 2013: 4(8); 3087-3093. doi: 10.13040/IJPSR. 0975-8232.4(8).3087-93

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