生物體內自由基的存在與許多疾病息息相關，蔬果中的抗氧化物質，如類黃酮類化合物可與自由基結合，降低自由基對生物體造成的傷害。芹菜素為一黃酮類化合物，研究指出其可加速癌細胞凋零、抑制癌細胞生長以及增加體內氧化壓力抗性。本研究欲以秀麗隱桿線蟲為模式生物，探討芹菜素於生物體內之抗氧化保護作用。化學試驗部分以維生素C當做對照成分，測試芹菜素 (1, 10, 50, 100 μM) 對於DPPH之清除能力；生物試驗方面則餵食線蟲不同濃度 (1, 10, 100 μM) 之芹菜素，再投以線蟲活性氧生成劑-胡桃醌，造成線蟲體內氧化壓力的產生，評估線蟲的存活程度及體內活性氧化物含量。DPPH試驗結果顯示，低於50 μM之芹菜素幾乎沒有DPPH之清除能力，最高劑量之芹菜素 (100 μM) 對於DPPH之清除率僅6.56%；反觀線蟲試驗，1 μM之芹菜素便可有效提升線蟲處於氧化壓力下之存活率和降低體內活性氧化物之含量。以DPPH作為天然化合物抗氧化之篩選為常見之試驗法，結合本試驗之結果可知，DPPH之試驗結果與生物試驗有很大之落差，單以DPPH做為單一篩選條件，可能低估天然物之抗氧化能力，若以線蟲當做篩選之模式生物，則能更精準的達到篩選結果。

The presence of free radicals in vivo is related to many diseases, like cancer. Fruits and vegetables contain antioxidants such as flavonoids with scavenging properties to reduce damage caused by free radicals to organisms. Apigenin is a flavonoid that is present in fruits and vegetables. Several studies indicated that apigenin has abilities to induce cancer cells apoptosis, inhibit cancer cells growth and increase oxidative stress resistance. In this study, we used a DPPH assay and Caenorhabditis elegans as in vitro and in vivo assays, respectively, to evaluate antioxidative properties of apigenin. The DPPH results showed that 1, 10 μM and 100 μM apigenin failed to exhibit significant DPPH radical scavenging activity. In contrast, apigenin (1, 10, and 100 μM) significantly enhanced survival of C. elegans during juglone-induced oxidative stress and heatshock stress. In addition, apigenin (1, 10, and 100 μM) significantly reduced intracellular reactive oxygen species in worms. Our findings suggest that the DPPH assay alone might overlook some potential compounds with antioxidative properties and C. elegans was proven to be a useful model animal for screening natural compounds with antioxidative preperties.