Abstract

Nutrigenomics, a nascent field in nutrition and molecular biology plays a pivotal role in understanding the influence of bioactive dietary components on the structure, integrity and functions of the genome. In this study, the comparative effects of vitamin C (Vit C) and Nigerian local orange juice on the gene expression levels of superoxide dismutase (sod), tumour necrosis factor receptor (tnfr), p53 protein (p53), estrogen receptor (esr) and progesterone receptor (pgr) genes were evaluated in rat neuronal tissues.  5 ml/Kg bodyweight of freshly extracted orange juice and 20 mg/Kg bodyweight Vit C were administered orally to Sprague Dawley rats distributed into orange, vitamin C and control groups, respectively. Expressions of sod, tnfr, p53,esr and pgr genes were measured by relative quantification PCR using SYBR green chemistry. Data were analyzed using Applied Biosystems SDS software 1.4 and Graphpad prism 5.0. A 57.01 ± 6.37 fold significant (P<0.01) increase in tnfr gene was observed in the orange juice administered male group compared with the vitamin C (2.53 ±0.74 fold change) and control groups. Other genes investigated (sod, p53, pgr and esr) also showed different expression patterns but the mean differences between the test groups was not significant (P>0.05). Orange juice has been shown to posses the ability to increase significantly mRNA expression levels oftnfr gene in the brain neuronal tissues of male rats. The increase is probably mediated by other bioactive components in the orange juice rather than vitamin C.

Key words: Vitamin C, orange juice, relative quantification PCR, gene expression, brain tissue.