Ultrasound-assisted Supercritical Carbon Dioxide Extraction Research Articles

IFST Winning Articles

IFST Winning Articles

Isolation of triterpenic acid-rich extracts from Hedyotis corymbosa using ultrasound-assisted supercritical carbon dioxide extraction and determination of their fictitious solubilities

Abstract The present study investigated a green ultrasound-assisted supercritical carbon dioxide (USC–CO 2 ) process for extracting oleanolic acid (OA) and ursolic acid (UA) from Hedyotis corymbosa . Chrastil, Bartle and Kumar and Johnston models were used to correlate the experimental fictitious solubility data. The overall average absolute relative deviation ( AARD (%)) in solid solubility ranged from 3.632% to 6.529%, which indicates good agreement between the experimental fictitious solubility data and the modeled results. Using the correlation results, the total heat of solution and the enthalpies of vaporization and solvation for OA and UA in the USC–CO 2 extraction process were also estimated.

Extraction of α-humulene-enriched oil from clove using ultrasound-assisted supercritical carbon dioxide extraction and studies of its fictitious solubility

Clove buds are used as a spice and food flavoring. In this study, clove oil and α-humulene was extracted from cloves using supercritical carbon dioxide extraction with and without ultrasound assistance (USC–CO2 and SC–CO2, respectively) at different temperatures (32–50°C) and pressures (9.0–25.0MPa). The results of these extractions were compared with those of heat reflux extraction and steam distillation methods conducted in parallel. The extracts obtained using these four techniques were analyzed using gas chromatography and gas chromatography/mass spectrometry (GC/MS). The results demonstrated that the USC–CO2 extraction procedure may extract clove oil and α-humulene from clove buds with better yields and shorter extraction times than conventional extraction techniques while utilizing less severe operating parameters. Furthermore, the experimental fictitious solubility data obtained using the dynamic method were well correlated with density-based models, including the Chrastil model, the Bartle model and the Kumar and Johnston model.

Kinetic studies for ultrasound-assisted supercritical carbon dioxide extraction of triterpenic acids from healthy tea ingredient Hedyotis diffusa and Hedyotis corymbosa

Hedyotis diffusa and Hedyotis corymbosa are the major ingredient of healthy teas commonly consumed in China for health maintenance. The objective of the present study was to evaluate the kinetics of a green process of ultrasound-assisted supercritical carbon dioxide (USC-CO2) extraction for determining the content of oleanolic acid (OA) and ursolic acid (UA) in both herbs. The results elucidated various advantages of USC-CO2 extraction, which can significantly increase extraction yields and reduce the extraction time and solvent consumption at lower operational conditions than the conventional SC-CO2 and solvent extraction methods. The combined USC-CO2–HPLC method was further applied to extract and quantitate the OA and UA contents in samples obtained from different geographical regions. The experimental results obtained indicate that H. diffusa and H. corymbosa were a suitable source for OA and UA production and the OA and UA content in the samples from different sources were significantly different. Furthermore, the kinetics of USC-CO2 extraction was determined based on a second-order kinetic model. The activation energies of OA and UA were 6.784 and 4.981kJ/mol, respectively.

Sustainable Utilization of TCM Resources.

Sustainable development aims to maintain utilization of finite resources without exhausting them and meet the demand of present and future generations [1]. Sustainability can only be achieved by balancing production and consumption in a reasonable dimension. It offers a vision of progress that integrates immediate and longer-term objectives. However, the nature of our current resource use endangers their future survival. Moreover, the consequences of our resource use in terms of impacts on the environment may induce serious damage to the environment. Sustainable utilization of natural resources should combine market demand of raw materials, ecological stability, and social benefits [2] and regard them as inseparable and interdependent components in the whole progress of industrial production. Traditional Chinese Medicine (TCM) has a long history of application and has attracted more and more world-wide attention for its significant effect in prevention and treatment of diseases. Wild medicinal resource is the basis of TCM and accounts for nearly 80% of all the sources of Chinese herbs. With the development of the modern TCM industry and gradual degradation of the natural environment, natural reserves of medicinal resources face a tremendous amount of pressure. Many medicinal plants are at risk of extinction and some adulterants have appeared on the market bringing to attention the need to ensure sustainable utilization of medicinal resources. More and more measures have been taken to guarantee the supply [3] and identification [4–6] as well as quality control [7, 8] and new drug development [9]. In this special issue, a total of 15 papers have been devoted to sustainable utilization of TCM resources. Identification of Radix Astragali using DNA barcoding, DNA barcode-based PCR-RFLP, and diagnostic PCR for authentication of Jinqian Baihua She (Bungarus Parvus), using ITS2 to identify Ferula species and indirubin-containing medicinal plants, are included. Rapid identification of plants in the Asteraceae with improved RBF-ANN classification models based on MOS-sensor E-nose is also provided. Introduction and cultivation can supply raw medicinal materials in short supply and play an important role in the sustainable utilization of TCM. Prevention and cure of diseases and insect pests and characteristics of soil microbial community in ginseng cultivation are offered. A systematic review on the production mode of Chinese herbal medicines is also presented. This special issue also reports natural resource monitoring of Rheum tanguticum by multilevel remote sensing. Traceability based on chemical two-dimensional barcode for controlling quality in the whole process of the industrial chain of TCM is included. Finally, measuring Agarwood formation ratio quantitatively by fluorescence spectral imaging technique and determining oleanolic and ursolic acids using hyphenated ultrasound-assisted supercritical carbon dioxide extraction and chromatography are introduced. Readers of this special issue will find not only different identification methods and updated reviews on cultivation, but also some important issues influencing quality control. The industrial chain of TCM, from the production of raw materials to the sale of the finished products, is a complicated multilink process. There are still some key questions to be resolved in the whole process including but not limited to breeding, prevention and cure of diseases and insect pests, quality traceability, exploiting new medicinal resources, and the mechanism of drug metabolism. Shilin Chen Yitao Wang Zhongzhen Zhao Christine J. Leon Robert J. Henry

Determination of Oleanolic and Ursolic Acids in Hedyotis diffusa Using Hyphenated Ultrasound-Assisted Supercritical Carbon Dioxide Extraction and Chromatography.

Oleanolic acid (OA) and ursolic acid (UA) were extracted from Hedyotis diffusa using a hyphenated procedure of ultrasound-assisted and supercritical carbon dioxide (HSC–CO2) extraction at different temperatures, pressures, cosolvent percentages, and SC–CO2 flow rates. The results indicated that these parameters significantly affected the extraction yield. The maximal yields of OA (0.917 mg/g of dry plant) and UA (3.540 mg/g of dry plant) were obtained at a dynamic extraction time of 110 min, a static extraction time of 15 min, 28.2 MPa, and 56°C with a 12.5% (v/v) cosolvent (ethanol/water = 82/18, v/v) and SC–CO2 flowing at 2.3 mL/min (STP). The extracted yields were then analyzed by high performance liquid chromatography (HPLC) to quantify the OA and UA. The present findings revealed that H. diffusa is a potential source of OA and UA. In addition, using the hyphenated procedure for extraction is a promising and alternative process for recovering OA and UA from H. diffusa at high concentrations.