These authors contributed equallyChoi, et al.,: Reduction of H 2 O 2 -induced Cell Damage by Allium hookeri ExtractsThe aim of this study was to investigate the bioavailability of Allium hookeri root extracts and evaluate its beneficial effects on hydrogen peroxide (H 2 O 2 )-induced oxidative stress in cultured H9C2 cardiomyocytes. After H9C2 cardiomyocytes were treated with the AHE, a substantial decrease in the H 2 O 2 -induced cytotoxicity was observed in a dose dependent manner. These results suggest that AHE has beneficial effects on cardiac dysfunction which can be used as a valuable supplement in the health-care products.Key words: Allium hookeri, oxidative stress, cardiomyocyte, H9C2 cells Allium hookeri is a plant species that is native to south Asian countries including India, Burma, Sri Lanka and South western China [1] . Recently, the plant is successfully cultivated in other countries of South and Southeast Asia such as Korea where it is valued as a food supplement. Furthermore, this plant and/or its extracts are anticipated to have ameliorative properties to several human diseases [2] such as diabetes, other metabolic syndromes and allergy [3,4] . However, no reports are available about its effectiveness in complicated disorders of diabetes.A. hookeri is one of the new imported plant species in Korea where it is known with its common names such as Hooker chives, SamChe (in Korea) and is used as an alternative food additive in many countries. However, the effects of this plant, especially the roots ( fig. 1) and its extracts on oxidative stress in heart are not recognized so far.In the present study, the decrease in hydrogen peroxide-induced cytotoxicity was ascertained in rat neonatal cardiomyocytes (H9C2) after the administration of A. hookeri roots extracts to determine the ameliorative effect of plants and its extracts on circulation disorders [5][6][7] . Then, we examined the ameliorative effects of water extracts of A. hookeri (AHE) on hydrogen peroxide-induced cardiomyocytes damaged by cytotoxicity test.To obtain the rat heart myoblast cell line, H9C2 cells were purchased from the Korean Cell Line Bank (KCLB, Seoul, Korea). All chemical reagents were obtained from Sigma-Aldrich. Initially, roots of A. hookeri obtained from the Hyejeong Farm (Bosung, Korea) were thoroughly washed with water and freeze dried. For extraction of the sample, 100 g of dried samples were homogenized with distilled water by a Waring blender (HMF-1710; Hanil) to 2-4mm particle size. The freeze-dried sample (moisture content: <5%) was stored in a -80° freezer for further study. To determine the cell viability, EZ-Cytox Cell Viability Assay Kit (Daeil Labservice, Korea) or MTT *Address for correspondence E-mail: khpark@nambu.ac.kr