Analysis of supercritical fluid extraction of lycopodine using response surface methodology and process mathematical modeling

Supercritical Carbon Dioxide Extraction of Coumarins from the Aerial Parts of Pterocaulon polystachyum

Pterocaulon polystachyum is a species of pharmacological interest for providing volatile and non-volatile extracts with antifungal and amebicidal properties. The biological activities of non-volatile extracts may be related to the presence of coumarins, a promising group of secondary metabolites. In the present study, leaves and inflorescences previously used for the extraction of essential oils instead of being disposed of were subjected to extraction with supercritical CO2 after pretreatment with microwaves. An experimental design was followed to seek the best extraction condition with the objective function being the maximum total extract. Pressure and temperature were statistically significant factors, and the optimal extraction condition was 240 bar, 60 °C, and pretreatment at 30 °C. The applied mathematical models showed good adherence to the experimental data. The extracts obtained by supercritical CO2 were analyzed and the presence of coumarins was confirmed. The extract investigated for cytotoxicity against bladder tumor cells (T24) exhibited significant reduction in cell viability at concentrations between 6 and 12 μg/mL. The introduction of green technology, supercritical extraction, in the exploration of P. polystachyum as a source of coumarins represents a paradigm shift with regard to previous studies carried out with this species, which used organic solvents. Furthermore, the concept of circular bioeconomy was applied, i.e., the raw material used was the residue of a steam-distillation process. Therefore, the approach used here is in line with the sustainable exploitation of native plants to obtain extracts rich in coumarins with cytotoxic potential against cancer cells.

The Response Surface Optimization of Supercritical CO2 Modified with Ethanol Extraction of p-Anisic Acid from Acacia mearnsii Flowers and Mathematical Modeling of the Mass Transfer

A widely disseminated native species from Australia, Acacia mearnsii, which is mainly cultivated in Brazil and South Africa, represents a rich source of natural tannins used in the tanning process. Many flowers of the Acacia species are used as sources of compounds of interest for the cosmetic industry, such as phenolic compounds. In this study, supercritical fluid extraction was used to obtain non-volatile compounds from A. mearnsii flowers for the first time. The extract showed antimicrobial activity and the presence of p-anisic acid, a substance with industrial and pharmaceutical applications. The fractionation of the extract was performed using a chromatographic column and the fraction containing p-anisic acid presented better minimum inhibitory concentration (MIC) results than the crude extract. Thus, the extraction process was optimized to maximize the p-anisic acid extraction. The response surface methodology and the Box–Behnken design was used to evaluate the pressure, temperature, the cosolvent, and the influence of the particle size on the extraction process. After the optimization process, the p-anisic acid yield was 2.51% w/w and the extraction curve was plotted as a function of time. The simulation of the extraction process was performed using the three models available in the literature.

Methods of isolation and bioactivity of alkaloids obtained from selected species belonging to the Amaryllidaceae and Lycopodiaceae families

Alkaloids obtained from plants belonging to the Amaryllidaceae and Lycopodiaceae families are of great interest due to their numerous properties. They play a very important role mainly due to their strong antioxidant, anxiolytic and anticholinesterase activities. The bioactive compounds obtained from these two families, especially galanthamine and huperzine A, have found application in the treatment of the common and incurable dementia-like Alzheimer’s disease. Thanks to this discovery, there has been a breakthrough in its treatment by significantly improving the patient’s quality of life and slowing down disease symptoms – albeit with no chance of a complete cure. Therefore, a continuous search for new compounds with potent anti-AChE activity is needed in modern medicine. In obtaining new therapeutic bioactive phytochemicals from plant material, the isolation process and its efficiency are crucial. Many techniques are known for isolating bioactive compounds and determining their amounts in complex samples. The most commonly utilized methods are extraction using different variants of organic solvents allied with chromatographic and spectrometric techniques. Optimization of these methods and modification of their procedures potentially allows researchers to obtain the expected results. The aim of this paper is to present known techniques for the isolation of alkaloids, especially from three species Narcissus, Lycopodium and Huperzia that are a rich source of AChE inhibitors. In addition, innovative combinations of chromatographic and spectrometric methods and novel TLC-bioautography will be presented to enable researchers to better study the bioactivity of alkaloids.

Optimization of Pressurized Liquid Extraction of Lycopodiaceae Alkaloids Obtained from Two Lycopodium Species

Alkaloids of the Lycopodiaceae family are of great interest to researchers due to their numerous properties and wide applications in medicine. They play a very important role mainly due to their potent antioxidant, antidepressant effects and a reversible ability to inhibit acetylcholinesterase (AChE) enzyme activity. This property is of immense importance due to the growing problem of an increasing number of patients with neurodegenerative diseases in developed countries and a lack of effective and efficient treatment for them. Numerous studies have shown that Lycopodiaceae alkaloids are a rich source of AChE inhibitors. In the obtaining of new therapeutic phytochemicals from plant material, the extraction process and its efficiency is crucial. Therefore, the aim of this work was to optimize the conditions of modern PLE to obtain bioactive alkaloids from two Lycopodium species: L. clavatum L. and L. annotinum L. Five different solvents of different polarity were used for prepared plant extracts in order to compare the alkaloid content in and thereby effectiveness of the entire extraction. PLE parameters were used based on multiple studies conducted that gave the highest alkaloids recovery. Crude extracts were purified using solid-phase extraction (SPE) on Oasis HLB cartridge and examined by HPLC/ESI-QTOF-MS of the highly abundant alkaloids. To the best of our knowledge, this is the first time such high recoveries have been obtained for known Lycopodiaceae alkaloids. The best extraction results of alkaloid-lycopodine were detected in the dichloromethane extract from L. clavatum, where the yield exceeded 45%. The high recovery of annotinine above 40% presented in L. annotinum was noticed in dichloromethane and ethyl acetate extracts. Moreover, chromatograms were obtained with all isolated alkaloids and the best separation and quality of the bands in methanolic extracts. Interestingly, no alkaloid amounts were detected in cyclohexane extracts belonging to the non-polar solvent. These results could be helpful for understanding and optimizing the best conditions for isolating potent AChE inhibitors.

Green chemical engineering in China

In China, the rapid development greatly promotes the national economic power and living standard but also inevitably brings a series of environmental problems. In order to resolve these problems fundamentally, Chinese scientists have been undertaking research in the area of green chemical engineering (GCE) for many years and achieved great progresses. In this paper, we reviewed the research progresses related to GCE in China and screened four typical topics related to the Chinese resources characteristics and environmental requirements, i.e. ionic liquids and their applications, biomass utilization and bio-based materials/products, green solvent-mediated extraction technologies, and cold plasmas for coal conversion. Afterwards, the perspectives and development tendencies of GCE were proposed, and the challenges which will be faced while developing available industrial technologies in China were mentioned.

Natural Antioxidants in Foods and Medicinal Plants: Extraction, Assessment and Resources

Natural antioxidants are widely distributed in food and medicinal plants. These natural antioxidants, especially polyphenols and carotenoids, exhibit a wide range of biological effects, including anti-inflammatory, anti-aging, anti-atherosclerosis and anticancer. The effective extraction and proper assessment of antioxidants from food and medicinal plants are crucial to explore the potential antioxidant sources and promote the application in functional foods, pharmaceuticals and food additives. The present paper provides comprehensive information on the green extraction technologies of natural antioxidants, assessment of antioxidant activity at chemical and cellular based levels and their main resources from food and medicinal plants.