- 學位論文
以離子液體萃取虎杖醱酵粉中的白藜蘆醇與純化
Ionic liquids based extraction of resveratrol from the fermented powder of Polygonum cuspidatum and the following purification
摘要
白藜蘆醇，是一種多酚類化合物，見於葡萄、花生、桑椹、虎杖等植物。由於法國悖論，使得白藜蘆醇受到關注。現認為它除了可以預防心血管疾病，亦有抗氧化、抑制癌症與炎症、延緩老化、減緩阿茲海默症、預防糖尿病等功效，雖作用機制尚未有一定論，但是將白藜蘆醇應用在醫藥、保健食品方面，可為人們帶來好處。 常見用以萃取白藜蘆醇的方法有許多種，其中，超音波輔助萃取具有操作簡便、使用成本低兼具提高萃取效率等優點。為增加產量，我們選擇虎杖醱酵粉作為原料(白藜蘆醇苷經醱酵後會轉化成白藜蘆醇)；另外，引入離子液體替代傳統溶劑(如甲醇、乙醇)。離子液體，是一種由陰、陽離子組合而成的鹽類，狹義來說，視熔點在100oC以下的鹽類才稱作離子液體。它具有不昜揮發、黏度高、液態範圍寬廣、化學與熱穩定性佳等性質，而且對於許多無機與有機物質皆有很好的溶解能力，因此適合用於萃取。 有不少文獻皆指出將離子液體應用在萃取，可提升萃取效率或節省操作時間，並可增進對目標產物的選擇率。本實驗以1.0M [BMIM][Br](aq)進行萃取，結果顯示出在白藜蘆醇與大黃素二者之間，[BMIM][Br]偏好前者。然而，對植物進行萃取只是一個過程，欲得到純度較高的產物，還要對萃取物進行分離純化。前人的研究在得到最佳萃取條件之後，便不再接續下去，這可能是因為無法確定目標產物與離子液體是否能夠分開的緣故。因此，藉由液液相萃取，以乙酸乙酯從粗萃液中分離出白藜蘆醇；最終產物的回收率約為84.9%，而純度為45.2%。
並列摘要
Resveratrol, one of the polyphenolic compounds, is commonly found in grapes, peanuts, mulberries and Japanese knotweeds. Since the French Paradox was first described in 1979, there has been an increased focus on resveratrol due to its health benefits. Aside from its cardioprotective effects, resveratrol is considered to possess anti-oxidative, anti-carcinogenic, anti-inflammatory, and anti-aging activities, mitigate Alzheimer’s disease, and prevent diabetes. It is worth noting that, while resveratrol’s mechanism of actions involved in these diseases remain elusive, it has promising applications in the fields of pharmaceuticals and dietary supplements. A number of methods have been used for extracting resveratrol. Among them, ultrasound-assisted extraction method has several advantages, including simplicity, cost-effectiveness, and, nice extraction efficiency. To increase the amount of resveratrol, we used ionic liquids to extract resveratrol from the powder of fermented Polygonum cuspidatum. Ionic liquids are organic salts which are composed of anion and cation and have melting points below 100oC. Ionic liquids possess diverse properties, including non-volatility, high viscosity, a wide range of liquid phase, good chemical and thermal stabilities. Their excellent salvation capacity for many inorganic and organic substances is suitable for extraction. Several investigations have indicated that the extraction efficiency or the selectivity of the target products could be enhanced by using the ionic liquid-based extraction method. In this study, 1.0M [BMIM] [Br] (aq) was used to extract resveratrol. We found in this study that, while a high selectivity between resveratrol and emodin was obtained when 1.0M [BMIM] [Br] (aq) was used in the extraction step, a further purification/separation step was needed to obtain the product with higher purities. Given that the majority of the published work only focused on the examination of the optimum conditions of extraction with no further purification/separation of the target compounds, we performed liquid-liquid extraction using ethyl acetate to separate resveratrol from the crude extract. Our results demonstrated that the recovery and purity of resveratrol in the final product was found to be approximately 80% and 40%, respectively.