Supercritical antisolvent fractionation of propolis tincture

Effect of wax separation on macro- and micro-elements, phenolic compounds, pesticide residues, and toxic elements in propolis

Propolis, a natural product with many biological activities, is a resinous material produced by honeybees. It contains not only valuable components but also some possible contaminants in varying amounts. Hence, this study aimed to examine how the process step of wax separation affects certain elements, pesticide residues, and phenolic compounds in propolis. Total phenolics, elements, and some pesticide residues were analyzed in the crude propolis (CP samples), wax portion (W samples), and remaining propolis fraction (PF samples) after wax separation. Total phenolics of the CP samples were determined in the range of 31.90-45.00 mg GAE g-1 sample, while those of the PF samples were in the range of 54.97-162.09 mg GAE g-1 sample. Loss/reduction values by means of wax separation for phenolics were calculated as 10.88% and 17.89%, respectively. Pb contents of all PF samples were low (0.232-1.520 mg kg-1), but it was also noteworthy that nearly 40% or even more of Cr, As, Cd, and Pb were removed by wax separation. Removal of significant amounts of carbendazim (38.09%-67.35%), metalaxyl (81.57%-72.67%), tebuconazole (65.99%-78.36%), and propargite (88.46%-83.05%) was also achieved. Wax separation enables the removal of toxic substances from crude propolis without causing huge losses in phenolic compounds.

Perspectives for Uses of Propolis in Therapy against Infectious Diseases

Propolis has gained wide popularity over the last decades in several parts of the world. In parallel, the literature about propolis composition and biological properties increased markedly. A great number of papers have demonstrated that propolis from different parts of the world is composed mainly of phenolic substances, frequently flavonoids, derived from plant resins. Propolis has a relevant role in increasing the social immunity of bee hives. Experimental evidence indicates that propolis and its components have activity against bacteria, fungi, and viruses. Mechanisms of action on bacteria, fungi, and viruses are known for several propolis components. Experiments have shown that propolis may act synergistically with antibiotics, antifungals, and antivirus drugs, permitting the administration of lower doses of drugs and higher antimicrobial effects. The current trend of growing resistance of microbial pathogens to the available drugs has encouraged the introduction of propolis in therapy against infectious diseases. Because propolis composition is widely variable, standardized propolis extracts have been produced. Successful clinical trials have included propolis extracts as medicine in dentistry and as an adjuvant in the treatment of patients against COVID-19. Present world health conditions encourage initiatives toward the spread of the niche of propolis, not only as traditional and alternative medicine but also as a relevant protagonist in anti-infectious therapy. Production of propolis and other apiary products is environmentally friendly and may contribute to alleviating the current crisis of the decline of bee populations. Propolis production has had social-economic relevance in Brazil, providing benefits to underprivileged people.

Supercritical Extraction of Red Propolis: Operational Conditions and Chemical Characterization

The objective of this study was to determine the best operational conditions for obtaining red propolis extract with high antioxidant potential through supercritical fluid extraction (SFE) technology, using carbon dioxide (CO₂) as the supercritical fluid and ethanol as the cosolvent. The following parameters were studied: overall extraction curve, S/F (mass of CO₂/mass of sample), cosolvent percentage (0, 1, 2 and 4%) and global yield isotherms as a function of different pressures (250, 350 and 450 bar) and temperatures (31.7, 40 and 50 °C). Within the investigated parameters, the best conditions found were an S/F of 131 and the use of ethanol at the highest concentration (4% w/w), which resulted in higher extract yields and higher content of antioxidant compounds. Formononetin, the main biomarker of red propolis, was the compound found at the highest amounts in the extracts. As expected, the temperature and pressure conditions also influenced the process yield, with 350 bar and 40 °C being the best conditions for obtaining bioactive compounds from a sample of red propolis. The novel results for red propolis found in this study show that it is possible to obtain extracts with high antioxidant potential using a clean technology under the defined conditions.

Evaluation of the antioxidant profile and cytotoxic activity of red propolis extracts from different regions of northeastern Brazil obtained by conventional and ultrasound-assisted extraction

Propolis is a complex mixture of resinous and balsamic material collected from the exudates of plants, shoots, and leaves by bees. This study evaluated red propolis extracts obtained by conventional (ethanolic) extraction and ultrasound-assisted extraction of six samples from different regions of northeastern Brazil. The total phenolic compounds and flavonoids, in vitro antioxidant activity, concentration of formononetin and kaempferol and the cytotoxicity against four human tumor cell lines were determined for all twelve obtained extracts. Significant variations in the levels of the investigated compounds were identified in the red propolis extracts, confirming that the chemical composition varied according to the sampling region. The extraction method used also influenced the resulting propolis compounds. The highest concentration of the compounds of interest and the highest in vitro antioxidant activity were exhibited by the extracts obtained from samples from state of Alagoas. Formononetin and kaempferol were identified in all samples. The highest formononetin concentrations were identified in extracts obtained by ultrasound, thus indicating a greater selectivity for the extraction of this compound by this method. Regarding cytotoxic activity, for the HCT-116 line, all of the extracts showed an inhibition of greater than 90%, whereas for the HL-60 and PC3 lines, the minimum identified was 80%. In general, there was no significant difference (p>0.05) in the antiproliferative potential when comparing the extraction methods. The results showed that the composition of Brazilian red propolis varies significantly depending on the geographical origin and that the method used influences the resulting compounds that are present in propolis. However, regardless of the geographical origin and the extraction method used, all the red propolis samples studied presented great biological potential and high antioxidant activity. Furthermore, the ultrasound-assisted method can be efficiently applied to obtain extracts of red propolis more quickly and with high concentration of biomarkers of interest.

Chemical characterization and biological activity of six different extracts of propolis through conventional methods and supercritical extraction

Propolis is a natural product with many demonstrated biological activities and propolis extract has been used in the food, pharmaceutical and cosmetics industries. Different works have showed the variations in the chemical composition, and consequently, on the biological activity of the propolis that are associated with its type and geographic origin. Due to this study evaluated propolis extracts obtained through supercritical extraction and ethanolic extraction (conventional) in three samples of different types of propolis (red, green and brown), collected from different regions in Brazil (state of Bahia). Analyses were performed to determine the humidity, water activity, the content of total ash, proteins, lipids and fiber in raw propolis samples. The content of phenolic compounds, flavonoids, in vitro antioxidant activity (DPPH), catechin, ferulic acid and luteolin and antimicrobial activity against two bacteria (Staphylococcus aureus and Escherichia coli) were determined for all extracts. For the green and red ethanolic extracts the anti-leishmanicidal potential was also evaluated. The physicochemical profiles showed agreement in relation to the literature. The results identified significant differences among the extracts (p>0.05), which are in conformity with their extraction method, as well as with type and botanical origin of the samples. The extraction with supercritical fluid was not efficient to obtain extracts with the highest contents of antioxidants compounds, when compared with the ethanolic extracts. The best results were shown for the extracts obtained through the conventional extraction method (ethanolic) indicating a higher selectivity for the extraction of antioxidants compounds. The red variety showed the largest biological potential, which included the content of antioxidants compounds. The results found in this study confirm the influence of the type of the raw material on the composition and characteristics of the extracts. The parameters analysis were important to characterize and evaluate the quality of the different Brazilian propolis extracts based on the increased use of propolis by the natural products industry.

Determination of Parameters for the Supercritical Extraction of Antioxidant Compounds from Green Propolis Using Carbon Dioxide and Ethanol as Co-Solvent

The aim of this study was to determine the best processing conditions to extract Brazilian green propolis using a supercritical extraction technology. For this purpose, the influence of different parameters was evaluated such as S/F (solvent mass in relation to solute mass), percentage of co-solvent (1 and 2% ethanol), temperature (40 and 50°C) and pressure (250, 350 and 400 bar) using supercritical carbon dioxide. The Global Yield Isotherms (GYIs) were obtained through the evaluation of the yield, and the chemical composition of the extracts was also obtained in relation to the total phenolic compounds, flavonoids, antioxidant activity and 3,5-diprenyl-4-hydroxicinnamic acid (Artepillin C) and acid 4-hydroxycinnamic (p-coumaric acid). The best results were identified at 50°C, 350 bar, 1% ethanol (co-solvent) and S/F of 110. These conditions, a content of 8.93±0.01 and 0.40±0.05 g/100 g of Artepillin C and p-coumaric acid, respectively, were identified indicating the efficiency of the extraction process. Despite of low yield of the process, the extracts obtained had high contents of relevant compounds, proving the viability of the process to obtain green propolis extracts with important biological applications due to the extracts composition.

Low density supercritical fluids precipitation of 9-cis and all trans-β-carotenes enriched particulates from Dunaliella salina

In this study, supercritical anti-solvent (SAS) pulverization coupled with reverse phase elution chromatography was employed to isolate 9-cis and trans-β-carotenes from Dunaliella salina. Total concentration of 9-cis (134.7mg/g) and trans-β-carotene (204.2mg/g) was increased from 338.9mg/g of the ultrasonic extract to 859.7mg/g (338.9 for 9-cis and 520.8 for trans) of the elution fraction. The SAS pulverization of the collected fraction further produced submicron-sized particulates containing 932.1mg/g (355.6 for 9-cis and 576.5 for trans) of total β-carotenes with a recovery of 86.3% (83.9% for cis and 87.8% for trans). Effects of two SAS operational conditions on the purity, recovery of total β-carotenes, mean size and morphology of the precipitates were obtained from an experimentally designed method. Generation of micronized particulates enriched with 9-cis and trans-β-carotenes by low-density SAS was proved to be feasible and environmental benign.

Preparation of highly pure zeaxanthin particles from sea water-cultivated microalgae using supercritical anti-solvent recrystallization

Xanthophylls, including zeaxanthin, are considered dietary supplements with a potentially positive impact on age-related macular degeneration. Using pilot-scale column fractionation coupled with supercritical anti-solvent (SAS) recrystallization, highly pure zeaxanthin particulates were prepared from ultrasonic extracts of the microalgae, Nannochloropsis oculata, grown in sea water. Column partition chromatography increased the concentration of zeaxanthin from 36.2 mg/g of the ultrasonic extracts to 425.6 mg/g of the collected column fractions. A response surface methodology was systematically designed for the SAS process by changing feed concentration, CO(2) flow rate and anti-solvent pressure. Zeaxanthin-rich particles with a purity of 84.2% and a recovery of 85.3% were produced using supercritical anti-solvent recrystallization from the column eluate at a feed concentration of 1.5 mg/mL, CO(2) flow rate of 48.6 g/min and pressure of 135 bar.

Insulin nanoparticles for transdermal delivery: preparation and physicochemical characterization and in vitro evaluation

AIM

This work is aimed to study the feasibility of insulin nanoparticles for transdermal drug delivery (TDD) using supercritical antisolvent (SAS) micronization process.

METHODS

The influences of various experimental factors on the mean particle size (MPS) of insulin nanoparticles were investigated. Moreover, the insulin nanoparticles obtained were characterized by scanning electron microscopy (SEM), dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and thermogravimetric (TG) analyses.

RESULTS

Under optimum conditions, uniform spherical insulin nanoparticles with a MPS of 68.2 +/- 10.8 nm were obtained. The Physicochemical characterization results showed that SAS process has not induced degradation of insulin. Evaluation in vitro showed that insulin nanoparticles were accorded with the Fick's first diffusion law and had a high permeation rate.

CONCLUSION

These results suggest that insulin nanoparticles can have a great potential in TDD systems of diabetes chemotherapy.

Supercritical CO2 extraction and purification of compounds with antioxidant activity

Supercritical fluid extraction (SCFE), based on the utilization of a fluid under supercritical conditions, is a technology suitable for extraction and purification of a variety of compounds, particularly those that have low volatility and/or are susceptible to thermal degradation. The interest in SCFE is promoted by legal limitations of conventional solvents for food and pharmaceutical uses. The physicochemical properties of supercritical CO2 (higher diffusivity, lower viscosity, and lower surface tension than conventional solvents) facilitate mass transfer and allow an environmentally friendly operation. This article presents a comprehensive compilation of data on the supercritical CO2 extraction of antioxidant compounds from vegetal materials, with particular attention to those of a phenolic nature. Aspects concerning the supercritical operation for extraction and fractionation of antioxidants compounds are considered, including equilibrium solubility of pure compounds and effects of the operational conditions on the antioxidant activity of isolated fractions. The data are compared to those reported for synthetic antioxidants and natural extracts obtained by conventional solvent extraction from vegetal matrices.