輔酶CoQ10為人體中重要的脂溶性酵素，其對於皮膚具有增加角質細胞中谷胱甘肽（Glutathion）濃度、抑制磷酸酪胺酸酶（Phosphotyrosine kinase）活性、抑制膠原蛋白酶（Collagenase）活性、抑制細胞氧化與預防因照射紫外線引起表皮細胞中氧化型DNA之破壞等作用。然而，CoQ10的作用與其存在的狀態應有密切的關聯；文獻中曾提到CoQ10具有氧化態與還原態，其抗氧化之能力也有所差異。儘管如此，卻不曾見到市售含CoQ10之化粧品對其中所添加之CoQ10的型態有所說明。因此，本研究希望藉由高效能液相層析法分析輔酶CoQ10之型態與穩定性之間的關係，並分析數種市售CoQ10原料，了解該原料中CoQ10存在的型態並探討添加抗氧化劑對CoQ10狀態之影響，提供化粧品生產時添加CoQ10的重要參考。
在輔酶CoQ10之型態與穩定性之間的關係方面，本研究主要探討輔酶CoQ10隨時間的變化情形；而在抗氧化劑對CoQ10狀態之影響方面，實驗探討於CoQ10中添加抗壞血酸（Ascorbic Acid）或生育醇（Tocopherol）對CoQ10型態與隨時間的變化情形。
結果顯示，市售CoQ10標準品與購得的CoQ10原料均為氧化態。經由還原劑的作用，氧化態的CoQ10可轉變為還原態的CoQ10H2；分析結果發現氧化態CoQ10的濃度會隨時間而下降，樣品配置完成後至9~12週間， CoQ10的下降速率較快，12週之後CoQ10的變化速率即趨於平緩。而在樣品中添加Ascorbic Acid，發現氧化態之CoQ10會逐漸轉變成還原態之CoQ10H2。至於添加Tocopherol 之CoQ10樣品，則不見還原態CoQ10H2之出現，但CoQ10濃度下降速率卻可見明顯的減緩。此外，市售CoQ10原料需視其包覆方式選擇適當溶劑方可準確定量。 Coenzyme Q10 is an essential lipophilic enzyme in human body. It can increase the concentration of glutathion in keratinocyte, inhibit the activity of phosphotyrosine kinase, collagenase and possible oxidation of cells, and prevent oxidative DNA damage of keratinocytes induced by UV irradiation. Studies show CoQ10 can exist in the form of ubiquinol and ubiquinone, which have quite difference in the ability of antioxidation. However, no statement have been seen about the existing state of CoQ10 in any commercial CoQ10-cotaining products. Therefore, the purpose of study is to examine the existing state of CoQ10 in several commercial CoQ10 raw materials by high-performance liquid chromatographic analysis. The stability of CoQ10 and the effect of antioxidant were also studied. These information can be used as an important reference in the manufacturing of CoQ10-cotaining products. Therefore, the variation of Coenzyme Q10 concentration with time and the influences of antioxidants, such as ascorbic acid and tocopherol, were studied in this research.
The results show that all the CoQ10 chemicals and raw materials purchased for this study are in the oxidized form. The reduced form of coenzyme Q10, CoQ10H2, can only be obtained by reaction with reducing agent, such as NaBH4. The concentration of CoQ10 decreased rapidly in the first nine to twelve weeks. The decreasing rate of CoQ10 is reduced after 12 weeks. It is observed that the addition of ascorbic acid to the sample can gradually transform CoQ10 from oxidized form to the reduced form, CoQ10H2. However, this phenomena have not been observed in the sample with the addition of tocopherol. But even then, the decreasing rate of CoQ10 is smaller with the addition of tocopherol than CoQ10 alone.
Besides, commercial CoQ10 raw materials are often modified to give specific characteristics. An adequate pretrement method have to be selected according to the characteristics of the raw materials before CoQ10 can be accurately quantified.
