本研究擬以蕃茄 ( Lycopersicon esculentum Mill. ) 萃取物為材料，探討其對酪胺酸酶活性之抑制作用。由蕃茄萃取酪胺酸酶抑制劑萃取液利用氮氣加壓超過濾，通過Sephdex G-25膠體管柱層析進行部分純化，即為蕃茄酪胺酸酶抑制劑，其半抑制濃度 ( IC50 ) 為2.46 mg / mL。此抑制劑可把銅離子還原為亞銅離子，並且對o-醌類 ( o-quinone ) 形成具有強抑制力。其最適作用溫度為 50℃、最適作用酸鹼值為pH 4 - 5，而在 pH 4到pH 9之間都很穩定。以L-DOPA當基質時，蕃茄抑制劑與洋菇酪胺酸酶作用，以雙倒數作圖判斷屬於混合型抑制型態 ( mixed type inhibitor )。通過 Superdex peptide HR膠體管柱層析推測此抑制劑的分子量小於1.3 KDa，根據 Molish、Barfoed、Seliwanoff 和 Schiff試驗皆為正反應，推測此抑制劑可能為醣苷化合物。由本研究結果得知蕃茄酪胺酸酶抑制劑可抑制黑色素生成，於化妝品工業應用上頗具潛力。 This study investigated the effect of tomato (Lycopersicon esculentum Mill.) extracts on tyrosinase inhibition in acellular systems. The tyrosinase inhibitor from tomato was extracted. The tyrosinase inhibitor was partially purified with Sephadex G-25 gel filtration column chromatography. The IC50 value of tyrosinase inhibitor was 2.46 mg/ml. The inhibitor presents both the abilities of reduction Cu++ to Cu+ and inhibition on o-quinone formation. The optimal temperature of the inhibition activity of tyrosinase treated with the inhibitor was 50℃; optimal pH was 4-5. The inhibitor was stable at pH4-9. A kinetic analysis showed that the inhibitor was a mixed type inhibitor using L-DOPA as substrate. The molecular mass of tyrosinase inhibitor was below 1.3KD by Superdex Peptide HR column. The inhibitor was probably a glycosidyl compound, according to the positive reaction with Molish, Barford, and Seliwanoff test. The study indicating that tomato tyrosinase inhibitor may play and important role in regulation of melanin formation, making its potential in food and cosmetic industry.