The Study On Extraction Of Rosmarinic Acid From Rosemary And Their Antioxidant Ability Of The Rosemary Antioxidant

Rosemary(Rosmarinus officinalis L.), an evergreen shrub, which is a natural spiceberry of the family Labiatae, contained many kinds of bio-active substances. One of these substances was rosmarinic acid, which had very strong antioxidant ability. In this paper, the technics of extraction and purification of rosmarinic acid (RosA) from rosemary and the antioxidant ability of the extract were studied.Firstly, the extraction of rosmarinic acid from rosemary with microwave and ultrasonic wave was studied. The results showed that the optimal extracting technological conditions were as follows: 20 mesh(comminuted size, mesh), 15% (ethanol concentration, v/v), ratio of liquid to material (5:1), 10 min(the time of ultrasonic cells broken), 540w (the power of microwave),4 times (extracting times) and 6 min each time. Under these conditions, the extracting rate of rosmarinic acid could reach 94.54%. It showed that this method had the advantages of short extracting time, high yield and low-cost for extraction of rosmarinic acid.Secondly, the optimal conditions of purification were studied experimentally. The extraction liquid was clarified by ceramic micro-filter and used X-5 macroporous absorption resin to concentrate rosmarinic acid. The optimal adsorption conditions were determined: When the adsorption speed was 4 mL·min^-1, the resin could absorb 1500 mL extraction liquid , and 1300mL 75% ethanol was used to desorb.Thirdly, the gained concentration solution was purified by normal butanol, and the best condition of extraction was: When the solid concentration was 14.29%, pH=3, extraction time was 20min, the volume ratio of solution to normal butanol was 1:1.5, the extraction times was 2.Finally, the crystallization method was used to the further purify to gain the pure products. The qualitative analysis by HPLC showed that the content of the final rosmarinic acid products was 96.82%(w/w).Furthermore, the antioxidant activities of rosemary extract was studied. The rosmarinic acid products had a good antioxidant ability though it showed slightly lower reducing power and scavenging ability on superoxide radical(·O^-2) than ascorbic acid. And in order to make the best use of rosemary, the lipid-soluble antioxidant was extracted from the material dregs.All in all, the purity of rosmarinic acid products was high. The whole technics were short and easy to undertake in factory which had a good future in industrial application.