The present study was designed

to investigate the protective effects of spices against hydrogen peroxide- and nicotine-induced toxicity. Plant phenolic compounds are the most abundant class of natural products. The redox properties of phenolic hydroxyl groups are responsible for the radical scavenging activity of plant phenols. Hence, plants rich in phenols promote beneficial health effects in humans (Balasundram, Sundram, & Samman, 2006). In the present study, the total phenolic content of nine spices was analysed using the Folin–Ciocalteau method. All the spices showed high phenolic content, particularly, long pepper, pepper, clove and ginger (Fig. 1). Long pepper contains 2405 mg of gallic acid equivalents/100 g SCH727965 of dry weight of the spice, whereas cardamom, cumin, caraway, fennel and star anise ranged between 1131 and 1475 mg of GAE/100 g dry weight. The major types of phenols present in spices are phenolic

acids, phenolic diterpenes and flavonoids (Shan, Cai, Sun, & Corke, 2006). Most of these phenols are powerful antioxidants and exert various BEZ235 mw biological activities. In humans, the reactive oxygen species (ROS), including superoxide anion and hydroxyl radical, are continuously produced during normal respiratory processes. They induce lipid peroxidation, damage DNA and can lead to several degenerative disorders (Halliwell & Gutteridge, 1990). The effect of common spices on hydrogen peroxide- and nicotine-induced toxicity was analysed in this study. A dose-activity assay was first performed to select the concentration of H2O2 to be used in subsequent experiments. Cells (3T3-L1) treated with 25, 50 and 100 μM of H2O2 showed a dose dependent increase in tail length (Fig. 2). The maximum tail length (7.88 ± 0.78 μm) was shown by 100 μM H2O2 treatment and therefore this concentration was used to test the DNA protective properties of spices. Cells

pre-treated with different spice extracts (except pepper) at 5, 25 and 50 μg/ml, showed a significant Sclareol decrease (p < 0.05) in comet tail length compared to the control of H2O2 treatment alone ( Table 1). At low concentrations (5 μg/ml), long pepper, caraway, clove, cardamom and ginger showed significant DNA protecting activity (8–47%) whereas the other spices like star anise, fennel and cumin showed significant DNA protecting activity only at higher concentrations (25 and 50 μg/ml). Caraway, cardamom and ginger showed DNA protecting activity in all the concentrations tested whereas no significant activity was observed in cells treated with pepper. Previous studies on pepper reported the presence of a highly genotoxic alkaloid called piperine ( Madrigal-Bujaidar, Barriga, Mota, Guzman, & Cassani, 1997). Hence, the inability of pepper to protect DNA from H2O2-induced DNA damage can be attributed to the presence of toxic alkaloids.