Effect of dietary phytochemicals on peroxide induced oxidative stress in Lumbricus terrestris

Abstract

Oxidative stress has been linked to several chronic diseases, including heart disease, cancer and inflammation. Phenolic phytochemicals abundant in natural products have high antioxidant activity and can potentially reduce the effects of oxidative stress. However, their antioxidant response mechanism in vivo is not very well understood. Our objective was to investigate the effect of several natural products on modulating the antioxidant response in vivo in hydrogen peroxide (HP) stressed Lumbricus terrestris. Sexually mature L. terrestris were randomly divided into 4 treatment groups and were allowed to feed ad libitum on 1.25% Gerber‐oatmeal agar (GA). The animals in control, peroxide, treatment and treatment‐peroxide groups, fed on GA, GA + 0.13% HP, GA+ 10% extract and GA+0.13% HP+ 10% extract respectively. Two animals from each group were euthanized after 2d, 4d and 6d and 1 inch of circular muscle posterior to the clitellum was dissected and extracted. Malondialdehyde (MDA) levels were determined to assess peroxide induced lipid oxidation. The antioxidant response was determined by measuring the radical quenching activity of muscle, the levels of superoxide dismutase (SOD) and catalase (CAT) using standard methods. Our results indicated that compared to controls, animals on grapefruit, grape, ginger, and cranberry diet had the lowest MDA levels and high radical quenching activity. Animals on grapefruit, ginger, raspberry, and cranberry diet had 3‐7 fold more muscle CAT levels. SOD levels in animals on turmeric, mace, blackberry, and oregano diet was almost 100‐200 fold higher. Our results suggest that dietary phytochemicals can manage acute oxidative stress in vivo by inducing antioxidant enzyme response mediated by SOD and CAT.