| 摘要: | 本研究鑑定甘薯葉萃取物(sweet potato leaf extracts, SPLE)分析其綠原酸活性成分，並且藉由甘薯葉萃取物與其綠原酸成分的介入，以C2C12細胞模式，對葡萄糖體內平衡與GLUT- 4活性之影響，可能藉由Insulin- dependent pathway或Insulin- Independent pathway調節。使用UPLC-ESI-MS-MS鑑定三品種甘薯葉：CYY 98-59 (紫色缺刻型葉；P)、桃園2號 (綠葉；G)、亞蔬CN1927-16 (黃葉；Y) 其萃取物綠原酸活性成分，包括：Chlorogenic acid (CGA), Isochlorogenic acid A (ICAA；3,5-diCQA), Isochlorogenic acid B (ICAB；3,4-diCQA)和Isochlorogenic acid C (ICAC；4,5-diCQA)。並分析甘薯葉萃取物與CGAs對C2C12細胞中 2- NBDG攝入與GLUT- 4活性之影響。進而使用西方轉印分析(Western Blot, WB) 分析p-IR, p-IRS, p-Akt1, p-AMPKα活性表現。結果顯示：在三種甘薯葉的樣品中ICAA和ICAB含量顯著較高，其次為ICAC，因此推測在甘薯葉中ICAA、ICAB為綠原酸的主要組成。若加總Di-CQAs以黃葉含有最高Di-CQAs (33226.3 μg/g dry wt)。甘薯葉萃取物攝入2-NBDG以紫葉為最高、依序為Taoyuan 2、黃葉與CGA20和CGA10，但在後三者(黃葉、CGA20 、CGA10)與控制組相同，當前三者同樣具有最高GLUT4活性，CGA10和CGA20則次之。對於相關可能調節GLUT4活性的因子包括: 1. p-Akt1活性則以CGA20最高、次為CGA10、黃葉、Taoyuan 2、再次為紫葉；2. p-AMPK活性則以CGA20與黃葉最高、次為CGA10、Taoyuan 2、紫葉；3. p-IR於CGA 10、黃葉的蛋白表達顯著高於其他處理組且與CGA 20、紫葉表達量相當；4. p-IRS於CGA10、黃葉與CGA 20的蛋白表達顯著高於其他處理組。
不同品種甘薯葉萃取液與CGAs處理C2C12細胞後，透過GLUT4的表達和轉位來增強C2C12對2-NBDG攝取，其中GLUT4的表現量與中間訊號p-IR、p-IRS、p-Akt1和p-AMPKα的活化相關。由本研究結果得知，不同品種甘薯葉萃取液與CGAs可改善2-NBDG攝入，經由增強GLUT4的表現與改善下游相關訊號分子與其蛋白表現量有關。
This study identified sweet potato leaf extracts (SPLE) for the analysis of its chlorogenic acid active ingredient, and the effect of C2C12 cell model on glucose homeostasis and GLUT-4 activity by the intervention of sweet potato leaf extract and its chlorogenic acids (CGAs). It may be regulated by Insulin-dependent pathway or Insulin-Independent pathway. UPLC-ESI-MS-MS was used to identify three varieties of sweet potato leaves: CYY 98-59 (purple-nicked leaves; P), Taoyuan 2 (green leaves; G), and vegetable CN1927-16 (yellow leaves; Y). Chlorogenic acid (CGA) active ingredients, including Chlorogenic acid (CGA), Isochlorogenic acid A (ICAA; 3,5-diCQA), Isochlorogenic acid B (ICAB; 3,4-diCQA) and Isochlorogenic acid C (ICAC; 4,5-diCQA). The effects of sweet potato leaf extract on 2-NBDG uptake and GLUT-4 activity in C2C12 cells were analyzed. Further, Western transfer analysis (Western Blot, WB) was used to analyze the changes in p-IR, p-IRS, p-Akt1, p-AMPKα expression. The results showed that the contents of ICAA and ICAB in the three kinds of sweet potato leaf samples were significantly higher, followed by ICAC. Therefore, it is speculated that ICAA and ICAB in the sweet potato leaves are the main components of chlorogenic acid. If the sum of Di-CQAs is obtained, yellow leaves contain the highest Di-CQAs (33226.3 μg/g dry wt). The intake of 2-NBDG for sweet potato leaf extracts is highest in purple leaves, Taoyuan 2, yellow leaves and CGA20 and CGA10, but the latter three (yellow leaves, CGA20, CGA10) are the same as the control group while in the first three it also has the highest GLUT4 activity, followed by CGA10 and CGA20. For related factors that may regulate the activity of GLUT4: 1. For p-Akt1 activity, CGA20 is the highest, followed by CGA10, yellow leaves, Taoyuan 2, and second is purple leaves; 2. For p-AMPK activity, CGA20 and yellow leaves are the highest and second CGA10, Taoyuan 2, purple leaves; 3. The protein expression of p-IR in CGA 10 and yellow leaves was significantly higher than that of other treatment groups and was equivalent to the expression of CGA 20 and purple leaves; 4. The protein expression of p-IRS in CGA10, yellow leaves and CGA 20 was significantly higher than that of other treatment groups.
After treating C2C12 cells with different varieties of sweet potato leaf extracts and CGAs, the expression and translocation of GLUT4 enhances the uptake of 2-NBDG by C2C12. The expression level of GLUT4 and the intermediate signals p-IR, p-IRS, p-Akt1 and p-AMPKαis related. According to the results of this study, different varieties of sweet potato leaf extracts and CGAs can improve the intake of 2-NBDG. Enhancing the performance of GLUT4 is related to improving the downstream related signal molecules and its protein expression. |
