Concept: Supercritical carbon dioxide
The therapeutic application of Cannabis is attracting substantial public and clinical interest. The Cannabis plant has been described as a veritable ‘treasure trove’, producing more than a hundred different cannabinoids, although the focus to date has been on the psychoactive molecule delta-9-tetraydrocannabinol (THC) and cannabidiol (CBD). Other numerous secondary metabolites of Cannabis the terpenes, some of which share the common intermediary geranyl diphosphate (GPP) with the cannabinoids, are hypothesised to contribute synergistically to their therapeutic benefits, an attribute that has been described as the ‘entourage effect’. The effective delivery of such a complex multicomponent pharmaceutical relies upon the stable genetic background and standardised growth of the plant material, particularly if the raw botanical product in the form of the dried pistillate inflorescence (flos) is the source. Following supercritical CO2 extraction of the inflorescence (and possibly bracts), the secondary metabolites can be blended to provide a specific ratio of major cannabinoids (THC:CBD) or individual cannabinoids can be isolated, purified and supplied as the pharmaceutical. Intensive breeding strategies will provide novel cultivars of Cannabis possessing elevated levels of specific cannabinoids or other secondary metabolites.
Abstract Ethnobotanical surveys indicated that in the traditional medicines worldwide, several Juniperus species are utilized as antihelmintic, diuretic, stimulant, antiseptic, carminative, stomachic, antirheumatic, antifungal, and for wound healing. In the present study, essential oils obtained from heartwood samples of Juniperus virginiana L., Juniperus occidentalis Hook. and Juniperus ashei J. Buchholz were evaluated for wound healing and anti-inflammatory activities by using in vivo experimental methods. The essential oils were obtained by the supercritical carbon dioxide extraction method. Linear incision and circular excision wound models were performed for the wound-healing activity assessment. The tissues were also evaluated for the hydroxyproline content as well as histopathologically. To evaluate the anti-inflammatory activity of the essential oils, the test used was an acetic acid-induced increase in capillary permeability. The essential oil of J. occidentalis showed the highest activity on the in vivo biological activity models. Additionaly, the oil of J. virginiana was found highly effective in the anti-inflammatory activity method. The experimental data demonstrated that essential oil of J. occidentalis displayed significant wound-healing and anti-inflammatory activities.
The volatile oil parts of frankincense (Boswellia carterii Birdw.) were extracted with supercritical carbon dioxide under constant pressure (15, 20, or 25 MPa) and fixed temperature (40, 50, or 60°C), given time (60, 90, or 120 min) aiming at the acquisition of enriched fractions containing octyl acetate, compounds of pharmaceutical interest. A mathematical model was created by Box-Behnken design, a popular template for response surface methodology, for the extraction process. The response value was characterized by synthetical score, which comprised yields accounting for 20% and content of octyl acetate for 80%. The content of octyl acetate was determined by GC. The supercritical fluid extraction showed higher selectivity than conventional steam distillation. Supercritical fluid-CO(2) for extracting frankincense under optimum condition was of great validity, which was also successfully verified by the pharmacological experiments.
Oil and xanthorrhizol extraction from Curcuma xanthorrhiza Roxb. rhizome by supercritical carbon dioxide was optimized using Taguchi method. The factors considered were pressure, temperature, carbon dioxide flowrate and time at levels ranging between 10-25 MPa, 35-60 °C, 10-25 g/min and 60-240 min respectively. The highest oil yield (8.0 %) was achieved at factor combination of 15 MPa, 50 °C, 20 g/min and 180 min whereas the highest xanthorrhizol content (128.3 mg/g oil) in Curcuma xanthorrhiza oil was achieved at a factor combination of 25 MPa, 50 °C, 15 g/min and 60 min. Soxhlet extraction with n-hexane and percolation with ethanol gave oil yield of 5.88 %, 11.73 % and xanthorrhizol content of 42.6 mg/g oil, 75.5 mg/g oil, respectively. The experimental oil yield and xanthorrhizol content at optimum conditions agreed favourably with values predicted by computational process. The xanthorrizol content extracted using supercritical carbon dioxide was higher than extracted using Soxhlet extraction and percolation process.
Phytosterols provide important health benefits especially lowering of cholesterol. From environmental and commercial point of views, the most appropriate technique has been searched to extract the phytosterols from plant matrices. As a green technology, supercritical fluid extraction (SFE) using carbon dioxide (CO2 ) is widely used to extract bioactive compounds from different plant matrices. Several studies have been performed to extract phytosterols using supercritical CO2 (SC-CO2 ) and this technology has clearly offered a potential advantages over conventional extraction methods. However, the efficiency of SFE technology fully relies on the processing parameters, chemistry of interest compounds, nature of the plant matrices and expertise of handling. This review covers the SFE technology with particular reference to phytosterols extraction using SC-CO2 . Moreover, chemistry of phytosterols, properties of supercritical fluids (SFs) and the applied experimental designs have been discussed for better understanding of phytosterol solubility in SC-CO2 .
The aim of this study was to optimize the antioxidant activity of Piper nigrum L. essential oil extracted using the supercritical carbon dioxide (SC-CO2) technique. Response surface methodology was applied using a three-factor central composite design to evaluate the effects of three independent extraction variables: pressure of 15-30MPa, temperature of 40-50°C and dynamic extraction time of 40-80min. The DPPH radical scavenging method was used to evaluate the antioxidant activity of the extracts. The results showed that the best antioxidant activity was achieved at 30MPa, 40°C and 40min. The extracts were analyzed by GC-FID and GC-MS. The main components extracted using SC-CO2 extraction in optimum conditions were β-caryophyllene (25.38±0.62%), limonene (15.64±0.15%), sabinene (13.63±0.21%), 3-carene (9.34±0.04%), β-pinene (7.27±0.05%), and α-pinene (4.25±0.06%). The essential oil obtained through this technique was compared with the essential oil obtained using hydro-distillation. For the essential oil obtained by hydro-distillation, the most abundant compounds were β-caryophyllene (18.64±0.84%), limonene (14.95±0.13%), sabinene (13.19±0.17%), 3-carene (8.56±0.11%), β-pinene (9.71±0.12%), and α-pinene (7.96±0.14%). Radical scavenging activity of the extracts obtained by SC-CO2 and hydro-distillation showed an EC50 of 103.28 and 316.27µgmL(-1) respectively.
Black pepper (Piper nigrum L.), the King of Spices is the most popular spice globally and its active ingredient, piperine, is reportedly known for its therapeutic potency. In this work, enzyme-assisted supercritical carbon dioxide (SC-CO2) extraction of black pepper oleoresin was investigated using α-amylase (from Bacillus licheniformis) for enhanced yield of piperine-rich extract possessing good combination of phytochemical properties. Optimization of the extraction parameters (without enzyme), mainly temperature and pressure, was conducted in both batch and continuous modes and the optimized conditions that provided the maximum yield of piperine was in the batch mode, with a sample size of 20 g of black pepper powder (particle diameter 0.42 ± 0.02 mm) at 60°C and 300 bar at 2 L/min of CO2 flow. Studies on activity of α-amylase were conducted under these optimized conditions in both batch and continuous modes, with varying amounts of lyophilized enzyme (2 mg, 5 mg and 10 mg) and time of exposure of the enzyme to SC-CO2 (2.25 h and 4.25 h). The specific activity of the enzyme increased by 2.13 times when treated in the continuous mode than in the batch mode (1.25 times increase). The structural changes of the treated enzymes were studied by (1)H NMR analyses. In case of α-amylase assisted extractions of black pepper, both batch and continuous modes significantly increased the yields and phytochemical properties of piperine-rich extracts; with higher increase in batch mode than in continuous.
Detailed analysis of the voltammetry of decamethylferrocene at micro and macrodisc electrodes has been carried out in scCO2/MeCN (15 wt%), 20 mM [NBu(n)4][BF4] and 309 K and 17.5 MPa. A passivating film needs to be removed from platinum electrodes before stable, reproducible voltammetry can be obtained. At low concentrations (0.22 mM) reversible 1e(-) behaviour is observed. Significant effects from natural convection are also present and it is demonstrated that fitting a baffle to the electrode dampens this effect. Limiting currents at microdisc electrodes at concentrations ranging from 0.22 to 11 mM and radii of 10 to 25 μm all obey the microdisc equation. The diffusion coefficient is calculated to be 4.06 × 10(-5) cm(2) s(-1) in scCO2/MeCN (15 wt%) with 20 mM [NBu(n)4][BF4] and 309 K at 17.5 MPa. The solubility of decamethylferrocene is in excess of 11 mM for these conditions.
Hylocereus polyrhizus and Hylocereus undatus are two varieties of the commonly called pitaya fruits, and pitaya fruits have gained popularity in many countries all over the world. However, studies on chemical composition and the nutritional quality of pitaya flesh peel are limited.
The H6P2W18O62/MCM-41-SUP was first synthesized using supercritical impregnation as highly efficient catalyst during glycerol conversion reaction. For comparison, the H6P2W18O62/MCM-41 prepared by conventional wet impregnation was also studied. The catalysts were studied using XRD, BET, FTIR, SEM, TEM, pyridine-FTIR, NH3-TPD, TG, ICP and elemental analysis. The characterization results showed that the preparation condition of supercritical carbon dioxide contributed to improve the dispersion of H6P2W18O62 on MCM-41, strengthen the interaction between H6P2W18O62 and MCM-41, increase the thermostability of H6P2W18O62 and enhance the amount of medium and Brønsted acid sites on the catalyst. Therefore, the formation of coke was retarded, and the lifetime of catalyst was prolonged. After 15 h reaction, the glycerol conversion rapidly reduced from 92% to 64% on H6P2W18O62/MCM-41-IMG (15.4 wt% coke), while the glycerol conversion slightly decreased from 94% to 82% on H6P2W18O62/MCM-41-SUP (9.8 wt% coke).