| The culinary herb rosemary (Rosmarinius officinalis L.) which is native to Europe, NorthAfrica and the Mediterranean coast，is planted in Yunnan,Guangxi, Hainan, Hunan, Sichuan,Guizhou, Fujian and other provinces in China during recent years. The comprehensiveutilizations of rosemary include rosemary essential oil, rosemary antioxidants, pharmaceuticalingredients (carnosic acid, carnosol, rosmarinic acid, oleanolic acid and ursolic acid) andleaves residue of rosemary etc., Which can not only improve resource utilization efficiency,reduce the production cost, make full use of their functions, but also be good to theenvironment.Ultrasound-assisted extraction from rosemary leaves is rapid, simple, efficient and theextracting rate of bioactive component has been greatly improved. Moreover, ethanol isnon-toxic and green to human body. This research provides a rapid and simultaneous HPLCmethod of five principal bioactive components. Firstly, the influence factors such as, ethanolconcentration, variety of acid stabilizer, acid stabilizer dosage, ultrasonic frequency, ultrasonicpower, ultrasonic extraction time and the solid-liquid ratio were studied. Secondly, thevariation regulation of five bioactive components in rosemary leaves and extraction procedurewas also studied. The effects of rosemary sources, vapor distillation time, activated carbondosage and storage time of extraction solution on variation regulation of bioactive componentswere discussed in detail. Thirdly, the study to track and detect the variation of bioactivecomponents in rosemary extraction solution and extracts, by adding organic polyacid, such ascitric acid, oxalic acid and tartaric acid, was performed.The ultrasound-assisted extraction results showed that the reasonable ultrasonic extractionconditions at room temperature were:75%(w/w) ethanol solution,3%(w/w) acid stabilizerbased on ethanol solution, ultrasonic frequency28kHz, ultrasonic power200W, ultrasonic extraction time40min, solid-liquid ratio1:16(g/mL). The extraction rate of carnosic acidreached18.64mg/g under the above extraction conditions.The better rosemary sources in this study included Henan, Guizhou, Xiamen, Guangxi andHunan. The suitable conditions for extraction procedure were respectively45min of vapordistillation time,8%activated carbon based on the mass of dried rosemary leaves fromGuizhou and3%hydrochloric acid based on the mass of ethanol solution. Hydrochloric acidcould stabilize carnosic acid and carnosol to some extent.The results of adding organic polyacid indicated that during the storage of the extractionsolution (≤70h) or the extracts (≤115d), the contents of the bioactive components werereduced not too much in a short period of time. For the storage of the extraction solution,tartaric acid was better than other two in slowing down the reduction of carnosic acid, butadding citric acid was more efficient in improving the yields of the extracts. The mixture oftartaric acid and oxalic acid was more efficient and greater than all the others when the yieldsof the extracts and the variation of their content were both considered. For the storage of theextracts, adding citric acid was more efficient in slowing down the reduction trend of carnosicacid and oleanolic acid than adding oxalic acid or tartaric acid, based on rosemary leaves,adding citric acid3%was more effective in improving the amount of carnosic acid andcarnosol, making carnosic acid more stable, the yield of carnosic acid can be improved by26.7%;3%oxalic acid was more effective to total of five, and improved its yield by5.3%.The research could guide the future pilot experiment of extraction and isolation, andprovide the basis for subsequent industrialization and deep processing of the rosemary extracts. |
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