ABSTRACT
Ionizing radiation causes damage to biomolecules in living cells through oxidative stress by excessive generation of reactive oxygen species (ROS) from radiolysis of body water. Blood and its components including the cells are exposed to a significant dose of radiation during irradiation. Grapes (Vitis vinifera L.) contain several bioactive phytochemicals and are rich source of antioxidants. Therefore, we hypothesized that the grape extracts would offer protection against the ionizing radiation-induced damage of the red blood cells (RBCs). To test our hypothesis, in the current study we investigated the radio-protective actions of extract of four different grape (Vitis vinifera) cultivars, namely Flame seedless (Black grapes), Kishmish chorni (Black with reddish brown), Red globe (Red) and Thompson seedless mutant (Sonaka, Green) against the g-irradiation-induced oxidative stress leading to the structural alteration in the RBC membrane in vitro. Freshly drawn blood samples from healthy volunteers itself or mixed with grape extracts from seed, skin or pulp of each cultivar were irradiated at 4 Gy after one hour of treatment. -irradiation for one hour did not change the hematological parameters. The average osmotic fragility (H50) and the maximum rate of hemolysis (dH/dC)max increased after the -irradiation. The confocal microscopic and atomic force microscopic (AFM) studies showed that irradiation induced transformation of RBC from biconcave cells to echinocytes, altered their surface roughness and the vertical distance. The grape extracts did not alter the viability of human erythrocytes. Our results suggested that the grape extract pretreatment ameliorated the ionizing radiation-induced alterations at a dose of 4 Gy in human erythrocytes in vitro. Moreover, protection offered by the seed extract was significantly better than that that of skin or pulp of the same cultivar. Furthermore, the protective action of grape extract depends on its source (seed, skin or pulp) as well on cultivars.
ABSTRACT
Ionizing radiation (IR) has become an integral part of the modern medicine— both for diagnosis as well as therapy. However, normal tissues or even distant cells also suffer IR-induced free radical insult. It may be more damaging in longer term than direct radiation exposure. Antioxidants provide protection against IR-induced damage. Grapes are the richest source of antioxidants. Here, we assessed the scavenging properties of four grape (Vitis vinifera) cultivars, namely Flame seedless (Black), Kishmish chorni (Black with reddish brown), Red globe (Red) and Thompson seedless mutant (Green), and also evaluated their protective action against -radiation-induced oxidative stress in liver tissue ex vivo. The scavenging abilities of grape seeds [2,2-diphenyl-1-picrylhydrazyl (DPPH) (IC50=0.008±0.001 mg/mL), hydrogen peroxide (IC50=0.49 to 0.8 mg/mL), hydroxyl radicals (IC50=0.08±0.008 mg/mL), and nitric oxide (IC50=0.8±0.08 mg/mL)] were higher than that of skin or pulp. Gamma () radiation exposure to sliced liver tissues ex vivo from goat, @ 6 Gy significantly (P <0.001) decreased reduced glutathione (GSH) content by 21.2% and also activities of catalase, glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione s-transferase (GST) by 49.5, 66.0, 70.3, 73.6%, respectively. However, it increased thiobarbituric acid reactive substances (TBARS) by 2.04-fold and nitric oxide level by 48.6% compared to untreated group. Further increase in doses (10 or 16 Gy) of -radiation correspondingly decreased GSH content and enzyme activities, and increased TBARS and nitric oxide levels. Grape extract treatment prior to ionizing radiation exposure ameliorated theses effects at varying extent. The seed extracts exhibited strong antioxidant potential compared to skin or pulp extracts of different grape cultivars against oxidative damage by ionizing radiation (6 Gy, 10 Gy and 16 Gy) in sliced liver tissues ex vivo. Grape extracts at higher concentration (10 mg extract/g liver tissue) showed stronger antioxidant potential against lower dose (6 Gy) of ionizing radiation. Our results suggest that grape extracts could serve as a potential source of natural antioxidant against lower doses of IR-induced oxidative stress in liver extracts ex vivo.
ABSTRACT
Ionizing radiation (IR) causes oxidative stress through overwhelming generation of reactive oxygen species (ROS) in the living cells leading the oxidative damage further to biomolecules. Grapevine (Vitis vinifera L.) posses several bioactive phytochemicals and is the richest source of antioxidants. In this study, we investigated V. vinifera for its phytochemical content, enzymes profile and, ROS- and oxidant-scavenging activities. We have also studied the fruit extract of four different grapevine viz., Thompson seedless, Flame seedless, Kishmish chorni and Red globe for their radioprotective actions in human lymphocytes. The activities of ascorbic acid oxidase and catalase significantly (P <0.01) differed among extracts within the same cultivar, while that of peroxidase and polyphenol oxidase did not differ significantly. The superoxide radical-scavenging activity was higher in the seed as compared to the skin or pulp of the same cultivar. Pretreatment with grape extracts attenuated the oxidative stress induced by 4 Gy γ-radiation in human lymphocytes in vitro. Further, γ-radiation-induced increase in caspase 3/7 activity was significantly attenuated by grape extracts. These results suggest that grape extract serve as a potential source of natural antioxidants against the IR-induced oxidative stress and also inhibit apoptosis. Furthermore, the protective action of grape depends on the source of extract (seed, skin or pulp) and type of the cultivars.
ABSTRACT
The phytochemicals present in the grapes are responsible for nutraceutical and health benfits due to their antioxidant properties. These phytochemicals, however, vary greatly among different cultivars. In this study, we evaluated the antioxidant potential and protective role of four different Indian grape (Vitis vinifera) cultivars extracts, namely Flame seedless (Black grapes), Kishmish chorni (Black with reddish brown), Red globe (Red) and Thompson seedless mutant (Sonaka, Green) against the Fenton-like reagent (200 mmole H2O2, 2 mmole ascorbate, 25 mmole FeSO4)-induced liver damage. Non-enzymatic antioxidants, such as glutathione (GSH) levels and activities of antioxidant enzymes, such as glutathione S-transferase (GST) and superoxide dismutase (SOD), as well as total antioxidant capacity (TAC) were highest in the grape seed, followed by skin and pulp. Among edible parts of different cultivars, skin of Flame seedless (Black) cultivar showed highest antioxidant potential, while the Thompson seedless the least potential. These antioxidants were found to be significantly (P<0.01) correlated with the levels of total phenol, flavonoids and ascorbic acid. Fenton-like reagent treatment significantly (P<0.001) decreased GSH content by 39.1% and activities of catalase (CAT) by 43.2% and glutathione reductase (GR) by 60%, while increasing thiobarbituric acid reactive substances (TBARS) and nitric oxide levels by 2.13-fold and 0.64-fold, respectively and GST activity by 0.81-fold. Pre-treatment with grape seed extracts showed the best hepatoprotective action against Fenton-like reagent-induced damage, followed by the extracts of skin and pulp of any cultivar. Thus, our study showed the significant amounts of antioxidants were in grape seed, followed by its skin and pulp, which varied among the cultivars and was associated with the protective action of grape extracts against Fenton-like reagent-induced liver damage ex-vivo.