Characterisation of ginger extracts obtained by subcritical water

Subcritical Water Extraction of Onosma mutabilis: Process Optimization and Chemical Profile of the Extracts

The aboveground and root parts of Onosma mutabilis were extracted using subcritical water and the process was optimized with response surface methodology. The composition of the extracts was determined by chromatographic methods and compared to that of conventional maceration of the plant. The optimum total phenolic contents for the aboveground part and the roots were 193.9 and 174.4 μg/g, respectively. These results were achieved at a subcritical water temperature of 150 °C, an extraction time of 180 min, and a water/plant ratio of 0.1, for both parts of the plant. Principal component analysis revealed that the roots contained mainly phenols, ketones, and diols, with the aboveground part mostly alkenes and pyrazines, whereas the extract from maceration contained mainly terpenes, esters, furans, and organic acids. The quantification of selected phenolic substances showed that subcritical water extraction compared favorably to maceration, especially with respect to pyrocatechol (1062 as compared to 10.2 μg/g) and epicatechin (1109 as compared to 23.4 μg/g). Furthermore, the roots of the plant contained twice as much of these two phenolics compared to the aboveground part. Subcritical water extraction of O. mutabilis is an environmentally friendly method that can extract selected phenolics at higher concentrations compared to maceration.

Development and Characterization of Functional Cookies Enriched with Chestnut Shells Extract as Source of Bioactive Phenolic Compounds

Chestnut (Castanea sativa) shells (CSs), an undervalued agro-industrial biowaste, have arisen as a source of bioactive compounds with promising health-promoting effects. This study attempted, for the first time, to develop a functional food, namely cookies, using a CS extract obtained by an eco-friendly technology (subcritical water extraction). The cookies were characterized regarding their nutritional composition, total phenolic and flavonoid contents (TPC and TFC, respectively), antioxidant/antiradical activities, phenolic profile, and sensory evaluation. The results demonstrated that the CS-extract-enriched cookies were mainly composed of carbohydrates (53.92% on dry weight (dw)), fat (32.62% dw), and fiber (5.15% dw). The phenolic profile outlined by HPLC-PDA revealed the presence of phenolic acids, flavonoids, and hydrolysable tannins, attesting to the high TPC and TFC. The in vitro antioxidant/antiradical effects proved the bioactivity of the functional cookies, while the sensory evaluation unveiled excellent scores on all attributes (≥6.25). The heatmap diagram corroborated strong correlations between the TPC and antioxidant/antiradical properties, predicting that the appreciated sensory attributes were closely correlated with high carbohydrates and phenolic compounds. This study encourages the sustainable recovery of antioxidants from CSs and their further employment as an active nutraceutical ingredient in functional cookies.

Subcritical Water Extraction as an Effective Technique for the Isolation of Phenolic Compounds of Achillea Species

The genus Achillea has significant medical potential due to the presence of highly bioactive compounds in its chemical composition. To take advantage of plants’ biomedical potential, it is of great importance to use a proper extraction process. This study aimed to determine and compare the preliminary chemical composition of five different Achillea species extracted with two conventional (infusion and maceration) and two non-conventional (ultrasound-assisted extraction (UAE) and Subcritical water extraction (SWE)) techniques. The extracts were prepared using the previously described procedures for infusion, maceration, UAE and SWE extraction. For all extracts, the extraction yield (dry extract (DE)) was determined. The analyzed extracts were preliminarily chemically characterized spectrophotometrically in terms of total phenolic content (TPC) and total flavonoid content (TFC). The obtained results showed that non-conventional techniques delivered higher values of TPC and TFC than conventional. There is a statistically significant increase in DE and TPC content when applying SWE for all observed Achillea species. The highest DE value, 48.80 ± 1.76%, was observed for A. asplenifolia. The highest TPC values were observed after applying SWE: 93.63 ± 1.01 mg GAE/g DE for A. millefolium, and 90.12 ± 0.87 mg GAE/g DE for A. crithmifolia. The results for TFC revealed a statistically significant difference in values, with A. nobilis subsp. nelreichii as the sample with the highest content of TFC (11.11 ± 0.22 mg QE/g DE) when using UAE. Consequently, it could be concluded that SWE is a superior non-conventional extraction technique, and A. nobilis subsp. nerleichii presents as the most promising plant.

Salicornia ramosissima: A New Green Cosmetic Ingredient with Promising Skin Effects

This study aims to validate a new cosmetic ingredient from Salicornia ramosissima S J. Woods through in vitro and ex vivo assays. The halophyte extracts were obtained by subcritical water extraction (SWE) at different temperatures (110, 120, 140, 160 and 180 °C). The antioxidant/radical scavenging activities and the phenolic profile were screened for all extracts. The optimal extract was assessed in keratinocytes and fibroblasts, while permeation assays were performed in Franz cells. The inhibitory activity of hyaluronidase and elastase was also evaluated. The sample extracted at 180 °C presented the highest phenolic content (1739.28 mg/100 g of dry weight (dw)). Despite not being efficient in the sequestration of ABTS^•+, this extract scavenged the DPPH^• (IC₅₀ = 824.57 µg/mL). The scavenging capacity of superoxide (O₂^•-) and hypochlorous acid (HOCl) was also considerable (respectively, IC₅₀ = 158.87 µg/mL and IC₅₀ = 5.80 µg/mL). The cell viability assays confirmed the absence of negative effects on keratinocytes, while the fibroblasts' viability slightly decreased. The ex vivo permeation of rutin, quercetin and syringic acid after 24 h was, respectively, 11, 20 and 11%. Additionally, the extract showed a good elastase and hyaluronidase inhibitory activity. The results obtained support the S. ramosissima bioactivity as a cosmetic ingredient.

New Perspectives on the Sustainable Employment of Chestnut Shells as Active Ingredient against Oral Mucositis: A First Screening

Oral mucositis (OM), a common side effect of oncological treatment, is an oral mucosal disorder characterized by painful ulcerations and increased risk of infection. The use of natural antioxidants to suppress the redox imbalance responsible for the OM condition has emerged as an interesting approach to prevent/treat OM. This study aims to explore the chestnut (Castana sativa) shells as potential active ingredient against OM. Therefore, chestnut shells were extracted at different temperatures (110-180 °C) by Subcritical Water Extraction (SWE), aiming to recover antioxidants. The extracts were also evaluated against microorganisms present in the oral cavity as well as on human oral cell lines (TR146 and HSC3). The highest phenolic content was obtained with the extraction temperature of 110 °C, exhibiting the best antioxidant/antiradical activities and scavenging efficiencies against HOCl (IC₅₀ = 4.47 μg/mL) and ROO^• (0.73 μmol TE/mg DW). High concentrations of phenolic acids (e.g., gallic and protocatechuic acids) and flavanoids (catechin, epicatechin and rutin) characterized the phenolic profile. The antimicrobial activity against several oral microorganisms present in the oral cavity during OM, such as Streptococcus, Staphylococcus, Enterococcus, and Escherichia, was demonstrated. Finally, the effects on HSC3 and TR146 cell lines revealed that the extract prepared at 110 °C had the lowest IC₅₀ (1325.03 and 468.15 µg/mL, respectively). This study highlights the potential effects of chestnut shells on OM.

The Chemical Signatures of Water Extract of Zingiber officinale Rosc

Background: Ginger (Z. officinale Rosc.) is a common herb and is widely used as a diet-based or home therapy in traditional medicine worldwide. However, fresh ginger turns into dried ginger after kiln drying and shows a different treatment effect in clinical practice. Objective: To characterize the changes of major bioactive constituents in dried ginger after the processing of fresh ginger. Methods: A novel, ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UHPLC−QTOF/MS) method was established to characterize the changes in the bioactive constituents of dried ginger. The novel strategy was split into two steps: firstly, the MS selected the most intense precursor ions of tandem MS; then, target MS/MS acquisition with different collision energies (10, 20, and 40 eV) was used to characterize the compound’s accurate MS/MS spectra and compare the MS/MS spectrum with the building MS reference library and reference standards. Result: Fifty-three compounds, including diarylheptanoids, gingerols, gingerodiols, gingerdiones, and shogaol-related compounds, were identified based on summarized fragmentation patterns. Fifteen out of fifty-three compounds were diarylheptanoids, which was different from fresh ginger. Conclusion: These identified compounds could be used to characterize the quality of dried ginger, pharmacologic studies should focus on diarylheptanoids explaining the different treatment effects between fresh ginger and dried ginger.

Chemical composition and bioactivity of oilseed cake extracts obtained by subcritical and modified subcritical water

Recovery of bioactive compounds from biowaste is gaining more and more interest in circular economy models. The oilseed cakes are usually insufficiently exploited by most technologies since they represent valuable matrices abundant in proteins, minerals, and phytochemicals, but their use is mostly limited to feed ingredients, fertilizers or biofuel production. This study was thus focused on the exploration of new valorization pathways of oilseed cakes by subcritical water, representing a safe and economic alternative in the creation of value chains. Pumpkin, hemp, and flax seed cakes were treated with subcritical water in nitrogen and carbon-dioxide atmospheres, as well as in nitrogen atmosphere with the addition of acid catalyst. The degradation of carbohydrate fraction was studied by quantifying sugars and sugar degradation products in the obtained extracts. The extracts obtained under different conditions were further compared chemically with respect to total phenols and flavonoids, as well as to the content of individual phenolic compounds. Furthermore, the effects of subcritical water treatment conditions on antioxidant, antiradical and cytotoxic properties of thus obtained extracts were defined and discussed.

Optimization and Potentials of Kraft Lignin Hydrolysates Obtained by Subcritical Water at Moderate Temperatures

Kraft lignin was treated with subcritical water at moderate temperatures (120–220 °C) in different gas atmospheres, with the goal of optimizing its depolymerization under mild conditions. Lignin depolymerization was observed and compared using different homogeneous and heterogeneous catalysts in both nitrogen and carbon dioxide atmospheres. The most important treatment parameters for maximum lignin depolymerization and the highest yields of phenolic and other aromatic monomers were optimized. The influence of the process temperature, pressure, and time in both gas atmospheres was defined and optimized for maximum liberation of monomers into the aqueous phase. The yields of total phenols and other aromatics in the nitrogen atmosphere were the highest at 150 °C, whereas treatment in the carbon dioxide atmosphere required higher temperatures (200 °C) for a comparable efficiency. The effects of phenol addition as a capping agent in lignin depolymerization were observed and defined for both gas atmospheres. Phenol addition caused a remarkable increase in the total phenols content in the aqueous phase; however, it did not significantly affect the contents of other aromatics. The antioxidant properties of lignin hydrolysates obtained at different temperatures in different gas atmospheres were compared, correlated with the total phenols contents, and discussed, showing the promising potential of lignin hydrolysates obtained under mild subcritical water conditions.

Subcritical Water Extraction of Natural Products

Subcritical water refers to high-temperature and high-pressure water. A unique and useful characteristic of subcritical water is that its polarity can be dramatically decreased with increasing temperature. Therefore, subcritical water can behave similar to methanol or ethanol. This makes subcritical water a green extraction fluid used for a variety of organic species. This review focuses on the subcritical water extraction (SBWE) of natural products. The extracted materials include medicinal and seasoning herbs, vegetables, fruits, food by-products, algae, shrubs, tea leaves, grains, and seeds. A wide range of natural products such as alkaloids, carbohydrates, essential oil, flavonoids, glycosides, lignans, organic acids, polyphenolics, quinones, steroids, and terpenes have been extracted using subcritical water. Various SBWE systems and their advantages and drawbacks have also been discussed in this review. In addition, we have reviewed co-solvents including ethanol, methanol, salts, and ionic liquids used to assist SBWE. Other extraction techniques such as microwave and sonication combined with SBWE are also covered in this review. It is very clear that temperature has the most significant effect on SBWE efficiency, and thus, it can be optimized. The optimal temperature ranges from 130 to 240 °C for extracting the natural products mentioned above. This review can help readers learn more about the SBWE technology, especially for readers with an interest in the field of green extraction of natural products. The major advantage of SBWE of natural products is that water is nontoxic, and therefore, it is more suitable for the extraction of herbs, vegetables, and fruits. Another advantage is that no liquid waste disposal is required after SBWE. Compared with organic solvents, subcritical water not only has advantages in ecology, economy, and safety, but also its density, ion product, and dielectric constant can be adjusted by temperature. These tunable properties allow subcritical water to carry out class selective extractions such as extracting polar compounds at lower temperatures and less polar ingredients at higher temperatures. SBWE can mimic the traditional herbal decoction for preparing herbal medication and with higher extraction efficiency. Since SBWE employs high-temperature and high-pressure, great caution is needed for safe operation. Another challenge for application of SBWE is potential organic degradation under high temperature conditions. We highly recommend conducting analyte stability checks when carrying out SBWE. For analytes with poor SBWE efficiency, a small number of organic modifiers such as ethanol, surfactants, or ionic liquids may be added.

Use of D-optimal combined design methodology to describe the effect of extraction parameters on the production of quinoa-barley malt extract by superheated water extraction

Superheated water extraction was applied to produce quinoa-barley malt extract. D-optimal combined design was used to optimize the extraction conditions (time (min), solid-water ratio and particle size to obtain maximum protein and carbohydrate content, and minimum turbidity and pH. Quinoa flour (10%-30%), barley malt flour (70%-90%), different particle sizes (F = 420 µm, G = 710 µm), time (15-45 min), and solid-water ratio (0.1-0.2) were selected as independent variable and protein, carbohydrate, turbidity, and pH as dependent factors. Polynomials models satisfactorily fitted the experimental data with the R 2 values of .9961, .9909, .9949, and .9987, respectively. The protein and carbohydrate value was affected by superheated water extraction parameters. Our results revealed that increasing quinoa/barley malt ratio has significant effect on the turbidity and pH. The optimum extraction conditions were quinoa flour (30%), barley malt flour (70%), solid-water ratio (0.2), time (45 min), and particle size (F = 420 µm).

Optimization of microwave-assisted extraction of phenolic compounds from ginger (Zingiber officinale Rosc.) using response surface methodology

Introduction: Ginger (Zingiber officinale Rosc.) is a common spice and precious herbal plant in Vietnam. It contains many bioactive compounds, especially phenolic compounds useful for human health. Hence, the extraction and application of these compounds in medical technology are necessary.

Objective: The goal of this study is to determine the optimal extraction conditions with the assistance of microwave, for instance solvent/material ratio (ml/g), solvent concentration (%, v/v) and extraction time, on the extraction yield of ginger rhizome, such as total polyphenol content (TPC) and antioxidant capacity (AC).

Methods: The dried sample was extracted by microwave-assisted extraction (MAE). TPC and AC of received extract were measured by the Folin-Ciocalteu method and phenanthroline assay. The optimization process used response surface methodology (RSM) (Central composite face design, CCF) with major influencing factors including solvent concentration, solvent/material ratio and extraction time.

Results: The results showed that the optimal extraction conditions were the ethanol concentration of 60%, ethanol/material ratio of 48.6/1 (ml/g), extraction time of 1 minute.

Conclusion: The maximum TPC and AC peaked at 27.89±1.99 mg GAE/g dry matter and 12.24±0.04 mmol Fe/g dry matter (DM) at optimal extraction conditions. Besides, some factors strongly affected the extraction yield and interacted together.

Valorization Potential of Oilseed Cakes by Subcritical Water Extraction

The oil industry generates great quantities of oilseed cakes that remain after oil extraction. New technologies are required for their valorization, owing to their high nutritional value. Pumpkin, flax and hemp seed cakes were extracted by subcritical water under different conditions that included different gas atmospheres and homogenous catalysis, and for the first time their properties were directly compared. Extracts obtained in a nitrogen atmosphere, nitrogen atmosphere with the addition of a catalyst, and carbon dioxide atmosphere were chemically and nutritionally characterised. In the aqueous extracts obtained under different extraction conditions, the content of lipids, proteins and selected minerals (calcium, potassium, sodium and phosphorus) were determined. A detailed amino acid profile was determined by chromatographic analysis. The highest relative content of essential amino acids was observed in pumpkin seed extracts (51.49 ± 0.47 to 58.58 ± 0.45 mg/100 g dry extract), whereas hemp seed extracts were the richest in flavour amino acids aspartic acid, glutamic acid and alanine. Extraction in a carbon dioxide atmosphere or in nitrogen atmosphere with a HCl modifier released generally more minerals into the aqueous phase. Aqueous oilseed cake extracts demonstrated a favorable chemical composition and great nutritional value, opening new possibilities for exploitation of this biowaste. Based on the obtained results, oilseed cake extracts obtained by subcritical water have great potential to be used for the fortification of different food products, as well as in cosmetics.

Comparative Assessment of Phytochemical Profiles of Comfrey (Symphytum officinale L.) Root Extracts Obtained by Different Extraction Techniques

In this work a comparative study on phytochemical profiles of comfrey root extracts obtained by different extraction approaches has been carried out. Chemical profiles of extracts obtained by supercritical fluid (SFE), pressurized liquid (PLE), and conventional solid/liquid extraction were compared and discussed. Phytochemical composition was assessed by high-performance liquid chromatography coupled with electrospray time-of-flight mass spectrometry (HPLC-ESI-QTOF-MS/MS) identifying 39 compounds reported for the first time in comfrey root, mainly phenolic acids and fatty acids. The influence of different extraction parameters on phytochemical profiles of S. officinale root was investigated for all applied techniques. PLE and maceration, using alcohol-based solvents (aqueous methanol or ethanol), were shown to be more efficient in the recovery of more polar compounds. Greater numbers of phenolics were best extracted by PLE using 85% EtOH at 63 °C. The use of SFE and 100% acetone for 30 min enabled good recoveries of nonpolar compounds. SFE using 15% EtOH as a cosolvent at 150 bar produced the best recoveries of a significant number of fatty acids. The main compositional differences between extracts obtained by different extraction techniques were assigned to the solvent type. Hence, these results provided comprehensive approaches for treating comfrey root enriched in different phytochemicals, thereby enhancing its bioaccessibility.

Traditional Uses, Phytochemistry, and Pharmacological Properties of Zingiber officinale Essential Oil and Extracts

Ginger (Zingiber officinale) has been traditionally employed in south East Asia as well as India and China for treatment of nausea, asthma, fever, vomiting, cough, constipation, pain, arthritis, inflammation, etc. This chapter discusses the phytochemical composition and pharmacological studies of ginger extracts, ginger essential oil (GEO), and active bioactive constituents. The essential oil of fresh and dry ginger was ranged between 0.2% - 2.62% and 0.72% - 4.17% respectively. The bioactive constituent zingiberene, β-sesquiphellandrene, curcumene, β-bisabolene, β-farnesene, camphene, and gingerol and shogal are the major constituents in ginger extracts. These compounds are chief bioactive substances responsible for pharmacological activities such antioxidant, antidiabetic, anticancer, anticoagulant, antiradiation, anti-inflammatory, gastrointestinal, antimicrobial, cardiovascular, anti-obesity, and weight loss effects. Future research needs to investigate the suitable duration, maximum dosage of ginger, concerns of overdosage, and its side effects in animal models and humans.

Phytochemicals, antioxidant activity and hepatoprotective effect of ginger (Zingiber officinale) on diethylnitrosamine toxicity in rats

Context: Chronic liver damage has serious medical consequences. Objective: To investigate the hepatoprotective effect of dry Zingiber officinale (ginger) and its essential (volatile) oil against diethylnitrosamine (DEN) toxicity in rats. Materials and methods: Phenols and flavonoids components were characterized in dry ginger using HPLC-UV instrument while ginger essential oil (E.O.) was investigated via GC-MS technique. Antioxidant activity was determined in vitro. In rat model, ginger was administrated for 2 months. Lipid profile, antioxidant biomarkers, liver functions and histopathology were assessed. Results: Chlorogenic acid (63.85 ppm) and hesperidin (156.91 ppm) are among the major phenolic and flavonoid constituents in dry ginger. Curcumene (15.21%) and linalool (13.47%) represent the main E.O. constituents. In rats treated with ginger E.O., a significant elevation in serum HDL (31.14%) was accompanied by a decrease in LDL (55.14%). A significant decrease in serum ALT and ALP was reported (56.85% and 53.84%, respectively). Serum GSH-Px activity has significantly increased 75.06%. Meanwhile, E.O. showed anticancer potential against HepG2 cell line (IC50 = 40 µg/mL). Liver histopathological examinations confirmed the protective effect against abnormalities. Conclusion: Ginger was able to reduce the severity of DEN-cytotoxicity in rats, which suggests a novel antioxidant role originating from this medicinal plant.

Ginger: Panacea or Consumer’s Hype?

Ginger in its many forms, from juices of the fresh rhizome, to ginger powder and ginger essential oil, is growing in popularity for claimed universal health benefits. Nevertheless, and contrarily to the common notion of the public, ginger is not devoid of side effects, especially interactions with other drugs, and many of the claimed benefits remain to be substantiated. This work presents a comprehensive revision of the current state of the art on ginger pharmacokinetics and bioavailability, interaction with active pharmaceutical ingredients, raising awareness of the risks of uncontrolled ginger consumption. A second section of the work described the verified actions of various extracts of ginger, or of their main active ingredients, gingerols, based mainly on data obtained from controlled clinical trials. Finally, the last section is devoted to innovative technological solutions to improve the bioavailability of gingerols and ginger extracts that are expected to ultimately lead to the development of more consumer-compliant products.

Comparative in vitro studies of the biological potential and chemical composition of stems, leaves and berries Aronia melanocarpa's extracts obtained by subcritical water extraction

Preparation of functional products as well as natural-based products requires non-toxic but effective extraction techniques. In this study, subcritical water extraction was used for the extraction of different aronia parts in order to explore their potential. Stems, leaves and berries of Aronia melanocarpa were extracted under the following conditions: temperature 130 °C; pressure 35 bar; time 20 min. The total phenols and flavonoid contents of the produced extracts were evaluated by conventional spectrophotometric methods. Additionally, the main phenolic compounds were also identified and quantified by high performance liquid chromatography with diode array detection (HPLC-DAD). The biological potential of the extracts was evaluated by determining their antioxidant (DPPH, ABTS and lipid peroxidation assays), antimicrobial, enzyme inhibitory (cholinesterase and elastase) and cytotoxic effects (HeLa, A-549, LS-174T, MRC-5 cell lines). The results indicate that leaves and berries extracts exhibited stronger antioxidant action when compared with stems. The strongest cholinesterase and elastase inhibitory activity was also found in berries extract. Similarly, the extracts obtained from leaves and berries showed considerable cytotoxic effects against tested cell lines. A moderate antimicrobial effects was observed too. Demonstrated biological potential of all three aronia parts can trace a new road map for developing newly designed functional products.

Characterization of diarylheptanoids: An emerging class of bioactive natural products

Diarylheptanoids are a class of secondary plant metabolites with a wide variety of bioactivity. Research on their phytochemistry and phytoanalysis is rapidly growing and the number of identified structures bearing the aryl-C₇-aryl skeleton is at present approaching 500. Historically, the yellow pigment curcumin has been characterized as the first diarylheptanoid and the extensive research on naturally occurring analogues is still ongoing. In this review, studies dealing with the characterization of linear and cyclic derivatives are discussed from the phytoanalytical point of view. Isolation, fractionation and purification strategies from natural sources along with their chromatographic behavior and structural characteristics are discussed. The role of various techniques used for the extraction (such as Soxhlet extraction, sonication, maceration/percolation, microwave-assisted extraction, supercritical carbon dioxide extraction); isolation (liquid-liquid extraction, column chromatographic techniques, preparative thin-layer and high-performance liquid chromatography, centrifugal partition chromatography, counter-current chromatography); separation (thin-layer chromatography, high-performance liquid chromatography, gas chromatography, capillary electrophoresis) and structural characterization (UV/Vis spectroscopy, infrared spectroscopy, X-ray crystallography, mass spectrometry, nuclear magnetic resonance spectroscopy and circular dichroism spectroscopy) are critically reviewed.