BIOCHEMICAL TESTS FOR OXIDATIVE STRESS
In present study potential of Green grape methanolic extract, Black grape methanolic extract and Green + Black grape methanolic extract to modulate oxidative stress in swiss albino mice was evaluated through Lipid Peroxidase test (LPO), Superoxide Dismutase (SOD) method and Reduced Glutathione (GSH) estimation.
LPO of Green Grape methanolic extract, Black grape methanolic extract and Green + Black Grape methanolic extracts was calculated to be 56.8 ± 2.5 nM MDA/gm wet tissue, 36.1 ± 2.8 nM MDA/gm wet tissue and 48.25 ± 4.2 nM MDA/gm wet tissue respectively. Similarly, SOD of Green Grape methanolic extract, Black grape methanolic extract and Green + Black Grape methanolic extracts was found to be 94.7 ± 12.1 U/gm wet tissue, 165.2 ± 12.4 U/gm wet tissue and 122.6 ± 10.1 U/gm wet tissue and GSH of Green Grape methanolic extract, Black grape methanolic extract and Green + Black Grape methanolic extracts was found to be 0.6 ± 0.01 nmol/gm wet tissue, 0.9 ± 0.04 nmol/gm wet tissue and 0.7 ± 0.03 nmol/gm wet tissue respectively. Whereas LPO, SOD and GSH of control group was calculated as 74.4 ± 3.9 nM MDA/gm wet tissue, 54.1 ± 6.5 U/gm wet tissue and 0.4 ± 0.02 nmol/gm respectively. This shows that grapes produced protection by decreasing the activity of lipid peroxidation and at the same time levels of GSH and SOD were increased significantly to near the normal levels.
Present study can be correlated with the study of BVS L. et al. (2014) observed that black grape extract helped in declining the high level of the lipid peroxide level in serum and elevating the levels of antioxidant enzymes SOD and GSH, thus minimized the noxious effects of cadmium. Similarly, Almajwal A.M. and Elsadek M.F. (2015) evaluated the hepatoprotective activity of red grape (Vitis vinifera L.) dried seeds. In their study it was found that administration of red grape dried seeds lowered the lipid peroxidation level while it increased the enzymatic levels of GSH and LPO. Similarly, Dani C. et al. (2008) compared organic purple grape juice and conventional purple grape juice (V. Labrusca) for their in vivo antioxidant activities. It was observed that organic grape juice was richer in antioxidants as compared to the conventional grape juice. Both the grape juices were able to alter the lipid peroxidation profile to low level and SOD to higher level. Vitis vinifera L. leaves were studied for their antioxidant and anti-hypercholesterolemic potential by Devi S. and Singh R. (2017) and it was observed that Vitis vinifera Methanolic extract and Vitis vinifera Aqueous extract appreciably elevated serum catalase level and serum reduced glutathione level. In the same way Dogan A. and Celik I. (2012) studied the hepatoprotective and antioxidant role of grape (Vitis vinifera L.) seeds against ethanol-induced oxidative stress in which the tissues of brain, spleen, kidney, heart and liver of treated rats were observed and it was concluded that administration of rats with alcohol and alcohol + grape seed extract resulted changes in the level of MDA content (LPO), SOD and GSH.
Giribabu N. et al. (2016) analysed Vitis vinifera L. seed methanolic extract (VVSME) to treat myocardial damage among diabetic patients. Heart homogenates were used to determine levels of oxidative stress and it was observed that VVSME consumption reduced the level of LPO while it improved the levels of SOD, Catalase and GPx. Pirinccioglu M. et al. (2012) and Rodrigues A.D. et al. (2013) examined Okuzgozu and purple grapes juices respectively for their activity against oxidative stress and found that grape juices were effective in lowering the lipid peroxidation and inhibiting the reduction in enzymatic antioxidant defences i.e. SOD and GSH. A polyherbal formulation PartySmart containing various fruits including Vitis vinifera L. was determined for its inhibitory effect against alcoholic liver disease by Gopumadhavan S. et al. (2008) and it was proved to reduce oxidative stress by lowering the lipid peroxidation level thus beneficial in the treatment of alcohol-induced liver damage.
Present study encompasses the defensive properties of Green Grape methanolic extract, Black Grape methanolic extract and Green + Black Grape methanolic extract against oxidative stress in swiss albino mice. From the results it was concluded that Black Grape methanolic extract is superior in preventing the damage caused due to oxidative stress followed by Green + Black Grape methanolic extract and Green Grape methanolic extract when compared to control group. In control group the level of lipid peroxidation showed a significant increase while the levels of GSH and SOD showed a significant decrease. The increased lipid peroxidation and decreased SOD and GSH level in control group might have resulted from an elevation of reactive oxygen species caused due to stress condition in the mice with DMBA/Croton oil intoxication.
Grapes (Both green and black) have strong antioxidant properties and thus can protect cells and tissues against free oxygen radicals. The protective effect of black grape methanolic extract might be due to the presence of flavonoids, catalase and phenolic compounds including anthocyanins and resveratrol in black grapes. All of these compound work together and impart with synergistic antioxidant effect, scavenging and eliminating free radicals Johnston et al. (2005).
Furthermore, the mixture of Green Grape and Black Grape methanolic extract was found more effective in inhibiting oxidative stress as compared to Green Grape methanolic extract alone which implies that mixture of green and black grape methanolic extract synergistically enhance their in vivo antioxidant activities. The antioxidant properties of both black grapes and green grapes have been shown to suppress superoxide anion and lipid peroxidation and to delay the conjugation of dienes during lipid peroxidation Maffei-Facino et al. (1996). Both green and black grapes have been reported having amplified antioxidant properties. They help in avert from aging, recover skin and have huge amounts of fibre for digestion and vitamins to aid with immunity and strength.
So it can be concluded that when green and black grapes of varying potency were combined together they came out producing enhanced results as compared to the individual use of green grapes alone. Also, the positive interaction between both the grapes produced synergistic effect which can be pharmacodynamic synergism.