Studies on In-Vivo Antioxidant and Hepatoprotective of Citrus Sinensis (L.) Osbeck Peel Extract in Wistar Rats

ABSTRACT

Citrus sinensis is the commonest, most widely cultivated, and consumed citrus fruit. Large amounts of peel wastes are formed when consumed or processed, and suitable methods have to be adopted to utilize these waste materials for conversion into value-added products.

Flavonoids, the major component of citrus peel have been reported to exert antioxidant and activity.

This study was designed to investigate the in-vivo antioxidant and hepatoprotective properties of the methanol extract of citrus fruit peel in Wistar rats.

Qualitative and quantitative phytochemical screening was carried out on extracts of three different citrus species fruit peels for comparison and selection, after which C. Sinensis fruit peel extract was selected for further studies because it had the highest flavonoid content.

Oxidative stress and liver damage were induced in rats using 2 ml/kg subcutaneous injection of CCl4 every 72 h for 10 days. Biochemical parameters were assessed as indices of oxidative stress and liver damage.

Acute toxicity studies suggest that the LD50 (oral route) is above 5,000 mg/kg. The extract showed significant protection (at P<0.001) against the depletion of liver tissue catalase levels observed in the CCl4 treated group at 500 mg/kg (89% protection) comparable to that of the standard drug silymarin (84% protection).

INTRODUCTION

Background of Study

During normal body cells use oxygen and in the process generate highly reactive molecules known as free radicals capable of abstracting electrons (oxidation) from neighbouring cells (Moreira da Silva et al., 2010).

Oxidative stress is created when excessive free radicals react with proteins, cell walls, and DNA causing damage to cell that are critical to the immune system (Xiuzhen et al., 2007).

Free radicals can also be produced by inflammatory responses, stress, and environmental pollution.

When these free radicals are not removed and cell damage is not repaired, cell death occurs leading to a higher propensity for disease (Halliwell, 1992).

Many drugs, toxic substances, and infectious organisms are associated with hepatotoxicity due to their ability to generate free radicals and to cause a disturbance in hepatocyte biochemistry (Fernandez-Checa and Kaplowitz, 2005).

The free radicals generated are so high that they overpower the natural scavenger system leading to hepatic damage in the form of jaundice, cirrhosis, and fatty liver (Wolf, 1999).

Antioxidants are compounds that help prevent cellular damage caused by free-radical (Jacob, 1995). Fruits, vegetables and medicinal herbs are the richest sources of antioxidant compounds (Sies et al., 1992).

Many compounds extracted from plant sources have been identified as free radical or active oxygen scavengers (Ramarathnam et al., 1995).