Preparation of Allicin
Allicin is biosynthesized from alliin catalyzed by alliinase extracted from garlic, as previously reported(Liet al. , 2011). Alliin (purity ≥ 99%, batch No. AL160615) was accurately weighed and dissolved in DMEM medium to make the stock solutions (1.0 mg/mL). Alliinase (≥10000U/g, batch No. 201801001) was freshly prepared and dissolved at 37℃ to ensure optimal enzyme activity. Equal volumes were mixed for 30min at room temperature to ensure that alliin sufficiently reacted with alliinase. Centrifuged for 10 minutes at 4 °C at 12,000 rpm, the allicin stock solution was diluted immediately prior to experimentation. The allicin and alliinase were provided by Xinjiang Ailexin Pharmaceutical Co., Ltd (Xinjiang, China).