Gamma radiation effects in the brain of rats: antioxidant and radioprotective properties of <i>Vernonia amygdalina</i> leaf extract

Abstract

Radiotherapy side effects have been attributed to free radical reactions. This study evaluated the antioxidant activity of the methanolic extract of V. amygdalina (MEVA) against gamma irradiation-induced oxidative stress in rats' brain. Seventy male rats weighing 130-160 g were randomized into seven groups, with each group comprising ten rats namely: control, MEVA at 250, and 500 mg/kg/day, radiation only, radiation plus MEVA at 250, and 500 mg/kg/day, and alpha-tocopherol (TOCO). Rats were treated for 14 days, irradiated on the 15 th day, and euthanized on the 16 th day. Bioassays of malondialdehyde for lipid peroxidation (LPO), reduced glutathione (GSH), catalase (CAT), and superoxide dismutase (SOD) were carried out using standard techniques. Some of the brains were processed for paraffin wax embedment and stained with haematoxylin and eosin. Data were analyzed using ANOVA. Radiation caused a significant (p<0.01) elevation in LPO by about 142%. Pretreatment with 250 mg MEVA, 500 mg MEVA and TOCO reduced LPO significantly (p<0.01) by 56%, 65%, and 80% respectively, when compared with rats that received gamma radiation only. There was improvement in the histological alterations in the cerebellar layers and the Purkinje cell parameters of the pretreated groups when compared with the gamma-irradiated (R) group. MEVA demonstrated antioxidant and radioprotective effects in rats' brain.

Protective effects of Celosia argentea Linn. Vitamin E and dexamethasone on radiation-induced damage on the developing rat cerebellum

“…The significant reduction in GSH and an increase in MDA level, an end product of LPO in the Irrad alone group suggested that a state of oxidative stress occurred in the brains of the rats which might be due to increase in peroxidation of unsaturated fatty acids in the brain as a result of irradiation injury, a finding consistent with the reports of Adaramoye et al, (2010) and Owoeye et al (2010). MDA is the most often used biomarker to investigate oxidative damage in lipids due to cellular injury or disease (Uttara et al, 2009).…”

Antioxidative and Chemopreventive Properties of Vernonia amygdalina and Garcinia biflavonoid

“…Vernonia amygdalina , a member of the Asteraceae family, is a small shrub that grows in the tropical Africa with petiolate leaf of about 6 mm diameter and elliptic shape. However, in contrast to the 1–3 meters described as the height of the tree by some authors [ 14 – 16 ], the species found around the Department of Wildlife and Fisheries, University of Ibadan, Nigeria are tall trees of greater than 6 metres in height [ 17 ]. It is commonly called “bitter leaf” because of its bitter taste.…”

<em>Vernonia amygdalina</em> leaf extract and alpha-tocopherol alleviated gamma radiation-induced haematological and biochemical changes in rats

“…Of importance was the finding that pretreatment with MEVA and TOCO significantly reduced the elevated level of RSA to a level comparable to the control value. This may have been due to the stabilizing role of the antioxidants present in MEVA (Adaramoye et al, 2008;Owoeye et al, 2010), and TOCO (Schafer, 2002). TOCO is preferentially retained in the body by the action of the alphatocopherol transfer protein (α-TTP) in the liver, which preferentially incorporates it into lipoproteins that are circulated in the blood and ultimately delivers it to different tissues in the body.…”

“…That pre-treatment with MEVA and TOCO markedly reduced the elevated levels of AST, ALT, and ALP suggest that both MEVA and TOCO might act as an indirect or direct antioxidant by combining with toxic free radicals produced by radiation or inactivate them, thus preventing hepatocyte injury. This antioxidant activity would have led to the subsequent inhibition of the leakage of these enzymes into the circulation (Bender and Mayes 2003;Barone, 2004;Iwalokun et al, 2006;Owoeye et al, 2010).…”

“…Apart from synthetic antioxidants, studies have shown that commonly used medicinal plants, are also good sources of antioxidants that offer radioprotection in untried models. Examples include Aegele marmelos, Hibiscus sabdariffa, and Vernonia amygdalina (Jagetia et al, 2004;Adaramoye et al, 2008;Owoeye et al, 2010). Vernonia amygdalina, commonly called "bitter leaf' is a popular African vegetable whose health benefits have been reported (Igile et al, 1994).…”