Micro-mixing in flow-type process for supercritical CO2 extraction of ferulic acid and gallic acid from aqueous solution

Background: The consumption of antioxidants, including phenolic compounds, is considered important for preventing the oxidative damage diseases and ageing. The total polyphenol content (TPC) is the parameter used to estimate the quality of plant-derived products. Methods: Phenol oxidase activity of green bean (Phaseolus vulgaris) crude extract (in the presence of hydrogen peroxide) and banana (Musa sp.) pulp crude extract has been studied spectrophotometrically using catechol, gallic acid, caffeic acid, ferulic acid, and quercetin as substrates. All studied compounds have been oxidized in the presence of green bean crude extract and hydrogen peroxide; all studied compounds except ferulic acid have been oxidized in the presence of banana pulp crude extract. Michaelis constants (Km) and maximum reaction rates (Vmax) have been determined for oxidation in the presence of green bean crude extract and hydrogen peroxide (Km are 3.8×10-4 M, 1.6×10-3 M, 2.2×10-4 M, 2.3×10-4 M, 1.4×10-4 M and Vmax are 0.046 min-1, 0.102 min-1, 0.185 min-1, 0.053 min-1, 0.041 min-1 for catechol, gallic acid, caffeic acid, ferulic acid, and quercetin, respectively) and for oxidation in the presence of banana pulp crude extract (Km are 1.6×10-3 M, 3.8×10-3 M, 2.2×10-3 M, 4.2×10-4 M and Vmax are 0.058 min-1, 0.025 min-1, 0.027 min-1, 0.015 min-1 for catechol, gallic acid, caffeic acid, and quercetin, respectively). The influence of 3-methyl-2-benzothiazolinone hydrazone (MBTH) on the oxidation reactions kinetics has been studied: Michaelis constants values decrease and maximum reaction rates increase, which contributes to the increase in sensitivity of the determination. Results: Kinetic procedures of Total Polyphenol Content (TPC) determination using crude plants extracts in the presence of MBTH have been proposed (time of analysis is 1 min). For gallic acid (used as a standard for TPC determination) detection limit is 5.3×10-5 M, quantitation limit is 1.8×10-4 M, and linear range is 1.8×10-4 - 1.3×10-3 M for green bean crude extract; detection limit is 2.9×10-5 M, quantitation limit is 9.5×10-5 M, and linear range is 9.5×10-5 - 2.4×10-3 M for banana pulp crude extract. Proposed procedures are characterized by higher interference thresholds for sulfites, ascorbic acid, and citric acid compared to pure enzymes (horseradish peroxidase and mushroom tyrosinase) in the same conditions. Compared with standard Folin-Ciocalteu (FC) method the procedures described in this work are also characterized by less interference and more rapid determination. Conclusion: The procedures have been applied to TPC determination in tea, coffee, and wine samples. The results agree with the FC method for tea and coffee samples and are lower for wine samples, probably, due to sulfites interference.

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Optimized Supercritical CO2 Extraction Enhances the Recovery of Valuable Lipophilic Antioxidants and Other Constituents from Dual-Purpose Hop (Humulus lupulus L.) Variety Ella

Antioxidants ◽

10.3390/antiox10060918 ◽

2021 ◽

Vol 10 (6) ◽

pp. 918

Author(s):

Nóra Emilia Nagybákay ◽

Michail Syrpas ◽

Vaiva Vilimaitė ◽

Laura Tamkutė ◽

Audrius Pukalskas ◽

...

Keyword(s):

Supercritical Co2 ◽

Antioxidant Properties ◽

Extraction Yield ◽

Biologically Active ◽

High Yield ◽

Acid Extraction ◽

Supercritical Co2 Extraction ◽

Bioactive Constituents ◽

Total Extract

The article presents the optimization of supercritical CO2 extraction (SFE-CO2) parameters using response surface methodology (RSM) with central composite design (CCD) in order to produce single variety hop (cv. Ella) extracts with high yield and strong in vitro antioxidant properties. Optimized SFE-CO2 (37 MPa, 43 °C, 80 min) yielded 26.3 g/100 g pellets of lipophilic fraction. This extract was rich in biologically active α- and β-bitter acids (522.8 and 345.0 mg/g extract, respectively), and exerted 1481 mg TE/g extract in vitro oxygen radical absorbance capacity (ORAC). Up to ~3-fold higher extraction yield, antioxidant recovery (389.8 mg TE/g pellets) and exhaustive bitter acid extraction (228.4 mg/g pellets) were achieved under the significantly shorter time compared to the commercially used one-stage SFE-CO2 at 10–15 MPa and 40 °C. Total carotenoid and chlorophyll content was negligible, amounting to <0.04% of the total extract mass. Fruity, herbal, spicy and woody odor of extracts could be attributed to the major identified volatiles, namely β-pinene, β-myrcene, β-humulene, α-humulene, α-selinene and methyl-4-decenoate. Rich in valuable bioactive constituents and flavor compounds, cv. Ella hop SFE-CO2 extracts could find multipurpose applications in food, pharmaceutical, nutraceutical and cosmetics industries.

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1H nuclear magnetic resonance-based metabolite profiling of guava leaf extract: an attempt to develop a prototype for standardization of plant extracts

BMC Complementary Medicine and Therapies ◽

10.1186/s12906-021-03221-5 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Manasi S. Gholkar ◽

Jia V. Li ◽

Poonam G. Daswani ◽

P. Tetali ◽

Tannaz J. Birdi

Keyword(s):

Ferulic Acid ◽

Gallic Acid ◽

Plant Extracts ◽

Nmr Spectra ◽

Leaf Extract ◽

Partial Least Square ◽

Least Square ◽

E Coli ◽

H Nmr ◽

Guava Leaf

Abstract Background Herbal medicines are fast gaining popularity. However, their acceptability by modern practitioners is low which is often due to lack of standardization. Several approaches towards standardization of herbals have been employed. The current study attempted to recognize key peaks from 1H NMR spectra which together would comprise of a spectral fingerprint relating to efficacy of Psidium guajava (guava) leaf extract as an antidiarrhoeal when a number of unidentified active principles are involved. Methods Ninety samples of guava leaves were collected from three locations over three seasons. Hydroalcoholic (water and ethanol, 50:50) extracts of these samples were prepared and their 1H NMR spectra were acquired. Spectra were also obtained for quercetin, ferulic acid and gallic acid as standards. Eight bioassays reflecting different stages of diarrhoeal pathogenesis were undertaken and based on pre-decided cut-offs, the extracts were classified as ‘good’ or ‘poor’ extracts. The bioactivity data was then correlated with the 1H NMR profiles using Regression or Orthogonal Partial Least Square-Discriminant Analysis (OPLS-DA). Results OPLS-DA showed seasonal and regional segregation of extracts. Significant models were established for seven bioassays, namely those for anti-bacterial activity against Shigella flexneri and Vibrio cholerae, adherence of E. coli, invasion of E. coli and S. flexneri and production and binding of toxin produced by V. cholerae. It was observed that none of the extracts were good or bad across all the bioassays. The spectral analysis showed multiple peaks correlating with a particular activity. Based on NMR and LC-MS/MS, it was noted that the extracts contained quercetin, ferulic acid and gallic acid. However, they did not correlate with the peaks that segregated extracts with good and poor activity. Conclusions The current study identified key peaks in 1H NMR spectra contributing to the anti-diarrhoeal activity of guava leaf extracts. The approach of using spectral fingerprinting employed in the present study can thus be used as a prototype towards standardization of plant extracts with respect to efficacy.

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Supercritical CO2 extraction of Moroccan argan (Argania spinosa L.) oil: Extraction kinetics and solubility determination

Journal of CO2 Utilization ◽

10.1016/j.jcou.2021.101458 ◽

2021 ◽

Vol 46 ◽

pp. 101458

Author(s):

Adil Mouahid ◽

Isabelle Bombarda ◽

Magalie Claeys-Bruno ◽

Sandrine Amat ◽

Emmanuelle Myotte ◽

...

Keyword(s):

Supercritical Co2 ◽

Oil Extraction ◽

Supercritical Co2 Extraction ◽

Extraction Kinetics ◽

Argania Spinosa ◽

Solubility Determination

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Supercritical CO2 Extraction of Palladium Oxide from an Aluminosilicate-Supported Catalyst Enhanced by a Combination of Complexing Polymers and Piperidine

Molecules ◽

10.3390/molecules26030684 ◽

2021 ◽

Vol 26 (3) ◽

pp. 684

Author(s):

Andrea Ruiu ◽

Bernhard Bauer-Siebenlist ◽

Marin Senila ◽

W. S. Jennifer Li ◽

Karine Seaudeau-Pirouley ◽

...

Keyword(s):

Energy Saving ◽

Supercritical Co2 ◽

Supported Catalyst ◽

Precious Metals ◽

Palladium Oxide ◽

Supercritical Co2 Extraction ◽

Wide Range

Precious metals, in particular Pd, have a wide range of applications in industry. Due to their scarcity, precious metals have to be recycled, preferably with green and energy-saving recycling processes. In this article, palladium extraction from an aluminosilicate-supported catalyst, containing about 2 wt% (weight%) of Pd (100% PdO), with supercritical CO2 (scCO2) assisted by complexing polymers is described. Two polymers, p(FDA)SH homopolymer and p(FDA-co-DPPS) copolymer (FDA: 1,1,2,2-tetrahydroperfluorodecyl acrylate; DPPS: 4-(diphenylphosphino)styrene), were tested with regards to their ability to extract palladium. Both polymers showed relatively low extraction conversions of approximately 18% and 30%, respectively. However, the addition of piperidine as activator for p(FDA-co-DPPS) allowed for an increase in the extraction conversion of up to 60%.

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