This study performed to investigate the changes in S-allyl-L-cysteine (SAC) content of garlic with different cooking methods. Methods for determining SAC was validated by determining specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), precision and accuracy using HPLC-FLD system. Results showed high linearity in the calibration curve with a coefficient of correaltion (R 2 ) of 0.9999. The LOD and LOQ values for SAC were 0.15 and 0.49 μg/mL, respectively. The relative standard deviations (RSDs) for intra- and inter-day precision of SAC were less than 5%. The recovery rate of SAC was in the range from 97.35% to 97.47%. The SAC content of raw garlic was 2.77 mg/g, and there are no significantly difference among blanching and microwave treatment in SAC content. However, SAC content of boiling, autoclaving at 110℃ and 121℃ increased in the range of 3.50~9.19 mg/g, 6.52~16.21 mg/g and 14.15~50.24 mg/g as increasing cooking temperature and time, respectively.

Though hydrogen peroxide (H₂O₂) causes a deleterious effect to cells with its reactive oxygen species resulting in cell death, S-allyl cysteine (SAC, a bioactive organosulfur compound of aged garlic extract) has been known to have a cytoprotective effect. Few reported profiles of gene expression of H₂O₂ and SAC treated human cord blood derived mesenchymal stem cells (MSC). This study revealed changes in the profile of twenty-one genes grouped by oxidative stress, antioxidant, cell death, anti-apoptosis and anti-aging by quantitative real time PCR. A concentration of 100μM of SAC or 50μM of H₂O₂ was applied to MSC which show moderate growth and apoptosis pattern. H₂O₂ treatment enhanced expression of eleven genes out of twenty-one genes compared with that of control group, on the contrary SAC suppressed expression of eighteen genes out of twenty-one genes except C ros oncogene. SAC decreased expression of oxidative stress genes such as SOD1, CAT and GPX. These results seemed consistent with reports which elucidated over expression of NF-kB by H2O2, and suppression of it by SAC. This study will confer basic information for further experiments regarding the effects of SAC on gene levels.