APPLICATION OF IONIC LIQUIDS TO OBTAIN FLAVONOIDS FROM RED PROPOLIS

Red propolis was recently discovered in Brazil and its derived from the specie Dalbergia ecastophyllum. Some studies have shown antiparasitic, antioxidant and antitumor activities of this natural product. The presence of flavonoids is considered responsible for most of their biologic actions. In general, the main solvent used in the extraction of propolis bioactive is ethanol, however, in some regions of the world the consumption of this type of extract is not allowed for religious reasons. So, the objective of this work was developed a new method for extraction of propolis flavonoids with application of ionic liquids (LI’s) and compare the process yield with that obtained with ethanol. Red propolis samples were collected in the apiary in mid-April 2018, in the state of Alagoas. Two LI’s were tested in this work: 1-n-hexyl-3-methylimidazolium chloride ([HMIM][Cl]) and 1-n-butyl-3-methylimidazolium chloride ([BMIM][Cl]). To obtain the extracts, 0.5g of red propolis was mixed to the LI’s in a solid: liquid ratio of 1:3, using water as co-solvent and submitted to extraction in 80% amplitude ultrasound equipment for 5 minutes, followed by centrifugation at 4700rpm for 15 minutes. An ethanolic extract (95%) was prepared using the same experimental conditions for yield comparison purposes. Quantification of total flavonoids present in the extracts was performed using the method of Zhishen, Mengcheng and Jianming (1999) and the results expressed as rutin equivalents (RU)/g. Extraction with LI’s [BMIM][Cl] e [HMIM][Cl] in a 1:1 ratio with water resulted in 144.54 and 179.47mgRU/g, respectively. Using [HMIM][Cl] with 10% water as co-solvent resulted in a yield of 410.53mgRU/g, resulting in a statistically higher yield than ethanolic extract (295.85mgRU/g). [HMIM][Cl] proved to be a good alternative to using ethanol, confirming the potential of LI to extract flavonoids from red propolis.