山萵苣 （Lactuca indica） 是一菊科植物，在亞洲地區是一常見的野菜，也常被拿來當作抗菌或是抗發炎的民間用藥。
本研究探討山萵苣 （Lactuca indica） 甲醇萃取物之抗氧化與抑制酪胺酸酶效能。山萵苣甲醇萃取物經由乙酸乙酯及水分配層析後，分別使用 silica gel 60 和 diaion HP 20 進行管柱層析，共分得 12 個區段（E1-E6 和 W1-W6） ，之後比較各區段之抗氧化與抑制酪胺酸酶效能。抗氧化試驗包括 DPPH 自由基清除效能、 ABTS 自由基清除能力、還原能力，以及抑制脂質過氧化能力。
實驗結果顯示， DPPH 自由基清除效能、 ABTS 自由基清除能能力和還原能力，以水層粗萃物分離後的第3區段（W3）效果最好，W3 在 100ppm 時， DPPH 自由基清除效能為 94.18％，在 50ppm時，ABTS 自由基清除能能力為 101.32%，在 200ppm 時，還原能力相當於57.44ppm 的維生素C。總酚含量測定發現每克 W3 萃取物含有相當於753.80 mg 之 gallic acid ，而總類黃酮含量測定為每克萃取物含有相當於 191.94 mg 之 rutin。
在抑制脂質過氧化能力方面，則是水層粗萃物分離後的第 6 區段（W6）最好，200 ppm 時，抑制率達80.90 %。此外，抑制酪胺酸酶活性試驗顯示，於200 ppm 時，水層粗萃物分離後的第5區段（W5）抑制率可達103.90 %。綜合上述，粗萃物經過層析處理後，其區段粗萃物之抗氧化和抑制酪胺酸酶能力增加，應可為抗氧化和美白的潛力材料。 Lactuca indica (Compositae) is an edible wild vegetable, used as a folk medicine in anti-inflammatory,antibacterial, and other medications in Asia.
We investigated the antioxidant and antityrosinase activities of methanol extract of L. indica. Total crude extract (methanolic extract) was further divided into ethyl acetate (EtOAc) and water fractions by a liquid-liquid partition procedure.In addition, the EtOAc subfraction and the water subfraction were further fractionated by silica gel 60 and Diaion HP 20 columns into twelve subfractions inclusive E1-E6 and W1-W6. Then ,we compared anti-oxidation and inhibition of tyrosinase performance at each section. The antioxidant activities were carried out using various assays including their inhibitions of DPPH and ABTS radials, reducing power, and their inhibition of lipid peroxidation.
The third fraction of water (W3) is the most prominent in DPPH and ABTS inhibition assays. At 100 ppm, the scavenging activity in DPPH assay is 94.18% . At 50 ppm, the scavenging activity in ABTS assay is 101.32%
The reducing power of W3 at 200 ppm is equal to that of 57.44ppm vitamin C. The total phenol content of W3 is equal to 753.80 mg gallic acid and the total flavonoid content is equal to 191.94 mg rutin.
The most active sample in inhibiting lipid peroxidation is the sixth fraction of water (W6). At 200 ppm, its inhibitory effect on lipid peroxidation is 80.90%. At 200 ppm, the inhibitory effect on tyrosinase is 103.90% of the fifth fraction of water (W5).
In conclusion, the antioxidant and antityrosinase activities in the methanol extracts of L. indica. may play an important role in its further application in antioxidation and whitening products.
