菘藍萃取物抗氧化能力及抑制生理活性酵素之研究

菘藍 (Isatis indigotica Fortune) 屬於十字花科菘藍屬 (Isatis)，其葉片與根部均可作為藥材，主要功能為清熱與解毒，可用於治療喉嚨痛、感冒、發燒、頭暈與皮疹。文獻指出部分菘藍屬植物具免疫調節活性、抗氧化、抗病毒、抗菌、抗發炎等功能。但目前對於菘藍之科學研究文獻較少，故本研究以不同濃度乙醇(25%、50%、75%、95%)、熱水及甲醇萃取其葉片與根部，分別探討其抗氧化活性，並分析其活性成分及抑制生理活性酵素之探討。實驗結果顯示，葉片甲醇萃取組與根部95%乙醇萃取組具最高之總酚含量，其值分別為228.26及62.63 mg Gallic acid equivalent / g Dried weight，葉片及根部之總類黃酮含量亦以95%乙醇萃取組有最高含量，數據分別為196.83與37.88 mg Quercetin / g DW。葉片與根部各萃取組經高效能液相層析儀分析，比對標準品之滯留時間，推測兒茶素、芸香苷、木犀草素、楊梅素與槲皮素為葉片主要之酚類化合物，根部則以咖啡酸、兒茶素、阿魏酸及木犀草素為主要含有之酚類物質。於抗氧化實驗中，DPPH•與ABTS•+自由基清除能力，皆以葉片甲醇萃取組具最佳之清除率，其EC50值分別為32.91及326.25 μg/mL，根部25%乙醇萃取組與葉片熱水萃取組呈現最佳之螯合能力，EC50值分別為427.93及522.83 μg/mL，於還原力試驗中，葉片及根部萃取組皆以95%乙醇萃取組展現最佳還原能力，其EC50值分別為388.42與1891.27 μg/mL。於酵素抑制試驗中，葉片95%乙醇萃取物分別對於α-葡萄糖苷酶及黃嘌呤氧化酶表現出最佳抑制效果，其IC50分別為526.39與1084.89 μg/mL，而葉片25%乙醇萃取物呈現良好酪胺酸酶抑制能力，IC50為310.47 μg/mL。綜上所述，菘藍葉片與根部富含多種酚類化合物且具良好之抗氧化及酵素抑制能力，期許未來可作為保健食品開發之參考。

關鍵字

菘藍 (Isatis indigotica Fortune) ；抗氧化；酵素

並列摘要

Isatis indigotica Fortune belongs to the Brassicaceae family of Isatis genus. The leaf and root are used to medicinal herbs, the main function is clearing heat and detoxification, also can treat sore throat, cold, fever, dizzy and rash. According to the literature research previous studies, some plants of genus Isatis have immunomodulation, anti-oxidation, antiviral, antimicrobial and anti-inflammation activities etc. However, there are few scientific research of I. indigotica Fortune. Therefore, the leaf and root extracts were obtained using different concentrations of ethanol (25%, 50%, 75%, 95%), hot water and methanol solvents were employed. Furthermore, analysis of bioactive substances, antioxidant activity, inhibitory effects on physiological enzymes were conducted. The experimental data demonstrated that the methanol extract of leaf and 95% ethanol extract of root expressed the highest total phenolic contents, the results are 228.26 and 62.63 mg GAE / g DW respectively. Total flavonoids contents, 95% ethanol extract of leaf and root showed the highest result, there are 196.83 and 37.88 mg Quercetin/g DW, respectively. In antioxidant capacity, DPPH• and ABTS•+ radical scavenging ability, leaf methanol extract indicated the best free radical scavenging effect, the EC50 values are 32.91 and 326.25 μg/mL, respectively. Leaf hot water extract and root 25% ethanol extract exhibitd the greatest of ferrous ion chelating ability with EC50 value of 427.93 and 522.83 μg/mL respectively. In reducing power, leaf and root extracted by 95% ethanol demonstrate optimal reducing ability. The EC50 values are 388.42 and 1891.27 μg/mL. In inhibitory ability on enzymes, leaf 95% ethanol extract illustrated that the highest inhibition effect on α-glucosidase and xanthine oxidase with IC50 values of 526.39 and 1084.89 μg/mL, respectively. Leaf extracted by 25% ethanol indicate the greatest inhibition ability on tyrosinase, the IC50 value is 310.47 μg/mL. Conclusively, Isatis indigotica Fortune leaf and root extract have various of phenolic compounds, also shows excellent anti-oxidation and inhibition effect on enzyme. In the near future, our results may support an alternative for the development of dietary supplements.