Modulatory effect of spice extracts on iron-induced lipid peroxidation in rat liver

The antioxidants in foods play an important role in preventing the generation of reactive oxygen species (ROS). Some of the dietary constituents, commonly used in Indian foods such as cloves (Syzygium aromaticum), licorice (Glycyrrhiza glabra), mace (aril of Myristica fragrans) and greater cardamom (Amomum subulatum), were selected as the test samples to find their effect on the inhibition of lipid peroxidation (LPO) in rat liver homogenate. Three different oxidant systems were used to induce LPO. The results show that all the spices have antioxidant activities at various concentrations. None of the spices showed prooxidant properties. The effect of spices on the inhibition of LPO was concentration dependent. Cloves, mace and cardamom inhibited the initiation as well as propagation phases of FeCl3 induced LPO, while licorice inhibited the initiation phase only. The reducing power and the superoxide scavenging activity of spices was also measured in vitro. The reducing power of various spices increased with concentration. The percentage inhibition of superoxide radical generation by the spices was also observed to be concentration dependent. The results show that spices used in the present study have significant ability to inhibit LPO due to their polyphenol content, strong reducing power and superoxide radical scavenging activity. Cloves showed the highest antioxidant activity probably due to the higher polyphenol content as compared to other spices.