Article

Supercritical fluid extraction in herbal and natural product studies - A practical review

Department of Chemistry, University of Idaho, Москва, Idaho, United States
Talanta (Impact Factor: 3.55). 02/2001; 53(4):771-782. DOI: 10.1016/S0039-9140(00)00557-9

ABSTRACT

Due to increasingly stringent environmental regulations, supercritical fluid extraction (SFE) has gained wide acceptance in recent years as an alternative to conventional solvent extraction for separation of organic compounds in many analytical and industrial processes. In the past decade, SFE has been applied successfully to the extraction of a variety of organic compounds from herbs and other plants. This review article presents the practical aspects of SFE applications in sample preparation, selection of modifiers, collection methods, on-line coupling techniques, means for avoiding mechanical problems, and approaches to optimization of SFE conditions. SFE can also be used to clean up pesticides from herb medicines. SFE processes can be modeled to acquire useful information for better understanding of the extraction, mechanisms and optimization of the extraction procedures. With increasing public interest in natural products, SFE may become a standard extraction technique for studying herbal, food and agricultural samples.

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    • "Modification of the solvent solvation power can be employed to achieve high selectivity of the extraction product from herbs. In addition, modification of the solvent solvation may be useful in the extraction of complex samples, such as plant materials[44,45]. "
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    ABSTRACT: Herbs are widely utilized in food and health industries. Their beneficial effects to the human body have been attributed to the presence of active phytochemical ingredients with some efficiency for disease treatment as well as for beauty and health enhancement. Public awareness on the adverse effects of synthetic chemical products also increased the demand for herbal products. Highly efficient herbal processing and extraction technologies have been developed to obtain the optimal amounts of active ingredients from herbs and cope with the rising demands for herbal products. This paper reviews the state-of-the-art development in herbal processing and extraction methods from the year 1991 until 2015. The paper begins with a brief history of herbal usage, followed by descriptions of ten types of extraction processes and critical analysis of their relative advantages and disadvantages. Scale-up considerations of the extraction methods are also presented. The paper concludes with a highlight of the current and future challenges facing the herbal industry.
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    • "scCO 2 can dissolve a wide range of organic compounds due to its low dipole moment, combined with Lewis acid-base interactions. Further, to configure the solubility profile, polar co-solvents such as ethanol or methanol can be added [5]. With a favorable critical point at 31 °C and 7.4 MPa, reaching above the critical point for scCO 2 is fairly accessible . "
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    ABSTRACT: Supercritical carbon dioxide (scCO2) is often used to replace harmful solvents and can dissolve a wide range of organic compounds. With a favorable critical point at 31 °C and 7.4 MPa, reaching above the critical point for scCO2 is fairly accessible. Because of the compressible nature of scCO2 and the large changes of viscosity and density with temperature and pressure, there is a need to determine the behavior of scCO2 in microfluidic systems. Here, the influence of how parameters such as flow rate, temperature, pressure, and flow ratio affects the length of parallel flow of water and scCO2 and the length of the created CO2 segments are investigated and modeled using multivariate data analysis for a 10 mm long double-y channel. The parallel length and segment size were observed in the laminar regime around and above the critical point of CO2. The flow ratio between the two fluids together with the flow rate influenced both the parallel length and the segment sizes, and a higher pressure resulted in shorter parallel lengths. Regarding the segment length of CO2, longer segments were a result of a higher Weber number for H2O together with a higher temperature in the channel.
    Full-text · Article · Oct 2015 · Journal of Micromechanics and Microengineering
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    • "The CO 2 remains the most commonly used fluid for SFE application because of its critical constants (T c =31.1°C and P c = 72.8 atm), low cost, non toxic and non flammable properties and it can be recycled or reused thus minimizes waste generation (Bruno et al., 1993; Lang and Wai, 2001). Origanum glandulosum Desf. "
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    DESCRIPTION: Dried flowers and leaves of Origanum glandulosum Desf. were submitted to hydrodistillation (HD) and supercritical fluid extraction with CO 2 (SFE). The essential oils isolated by HD and volatile oils obtained by SFE were analysed by GC and GC/MS. Total phenolics content and antioxidant effectiveness were performed. The main components of the essential oils from Bargou and Nefza were: p-cymene (40.4% and 39%), thymol (38.7% and 34.4%) and γ-terpinene (12.3% and 19.2%), respectively. The major components obtain by SFE in the volatile oil, from Bargou and Nefza, were: p-cymene (32.3% and 36.2%), thymol (41% and 40%) and γ-terpinene (20.3% and 13.3%). Total phenolic content, expressed in gallic acid equivalent (GAE) g kg -1 dry weight, varied from 12 to 27 g kg -1 dw, and the ability to scavenge the DPPH radicals, expressed by IC50 ranged from 44 to143 mg L -1 .
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