This study aimed at valorisation of sea buckthorn pomace (SBP) for the production of extracts containing valuable bioactive compounds. For this purpose, SBP defatted by supercritical CO2 was subjected to consecutive fractionation with pressurized ethanol and water, which yielded 11.9% and 4.8% of extracts, respectively. The extracts were evaluated for their antioxidant potential, phytochemical composition and antiproliferative effects against cancer cells. Water extracts exhibited remarkably higher values in Folin-Ciocalteu assay of total phenolic content, oxygen radical absorbance capacity (ORAC), ABTS●+/DPPH● scavenging and cellular antioxidant activity (CAA) assays and more efficiently inhibited proliferation of HT29 cells at non-cytotoxic concentrations measured in non-tumoral Caco2 cells. Among 28 detected and 21 quantified phytochemicals, flavonols with the structures of isorhamnetin (five compounds), quercetin (three compounds), kaempferol (three compounds) glycosides and catechin (six compounds) were the most abundant in the extracts. In conclusion, the applied method of fractionation of SBP produces promising natural antioxidant complexes with antiproliferative properties that could find potential applications in nutraceuticals, functional foods and cosmeceuticals.
Paeonia officinalis extracts from leaves and roots were tested for their antioxidant potential using in vitro chemical (Folin-Ciocalteu, 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), oxygen radical absorbance capacity (ORAC), hydroxyl radical antioxidant capacity (HORAC), hydroxyl radical scavenging capacity HOSC)) and cellular antioxidant activity (CAA) assays. Leaf extracts were stronger antioxidants than root extracts, while methanol was a more effective solvent than water in chemical assays. However, the selected water extract of leaves was a stronger antioxidant in CAA than the methanol extract (0.106 vs. 0.046 µmol quercetin equivalents/mg). Twenty compounds were identified by ultra performance liquid chromatography-quadrupole-time-of-flight (UPLC-Q-TOF) mass spectrometer, while on-line screening of their antioxidant capacity by high performance liquid chromatography (HPLC) with a DPPH•-scavenging detector revealed that gallic acid derivatives are the major peony antioxidants. Root water and leaf methanol extracts inhibited α-amylase in a dose dependent manner. The IC50 value for the strongest inhibitor, the methanol extract of leaves, was 1.67 mg/mL. In addition, the cytotoxicity assessment of extracts using human Caco-2 cells demonstrated that none of them possessed cytotoxic effects.
Pressing strawberries for juice generates large amounts of pomace, containing valuable nutrients and therefore requiring more systematic studies for their valorization. This study compared conventional solid-liquid (SLE) and pressurized liquid (PLE) extractions with ethanol (EtOH) and H2O for the recovery of bioactive compounds from strawberry pomace. The composition and bioactivities of the products obtained were evaluated. Among 15 identified compounds, quercetin-3-glucuronide, kaempferol-3-glucuronide, tiliroside, ellagic, malic, succinic, citric and p-coumaric acids were the most abundant constituents in strawberry pomace extracts. SLE-EtOH and PLE-H2O extracts possessed strong antioxidant capacity in DPPH• and ABTS•+ scavenging and oxygen radical absorbance capacity (ORAC) assays. Cytotoxicity, antiproliferative and cellular antioxidant activities in human cells of PLE-EtOH and PLE-H2O extracts were also evaluated. PLE-EtOH and PLE-H2O extracts possessed strong antioxidant activity, protecting Caco-2 cells upon stress stimuli, while PLE-EtOH extract showed higher antiproliferative activity with no cytotoxicity associated. In general, the results obtained revealed that properly selected biorefining schemes enable obtaining from strawberry pomace high nutritional value functional ingredients for foods and nutraceuticals.
In this study, the simulation of artificial conditions, containing various chemical additives similar to a bog environment, was hypothesised as a relatively short way to develop a more sustainable wood product with better properties. This study aimed to determine how hydrothermal treatment with different iron additives with and without tannic acid, performed at 100 °C for 75 h, changed the mass and density of wood of different tree species (Pinus sylvestris L., Picea abies (L.) H. Karst., Pseudotsuga menziesii (Mirb.) Franco, Juglans regia L., and Acer platanoides L.); total phenolic compounds in biobased solvents after the hydrothermal processing andiron concentration in different wood layers. We also aimed to determine the wood chemical composition using Fourier-transform infrared technique. The study results showed that the softwood samples were more susceptible to hydrothermal modification than the hardwood samples, indicated by minorly different intensities on infrared spectra. The FTIR results showed bands of hardwood and softwood samples which along with the spectral characterisation of the wood constituents, which can further be utilized for creating a larger FTIR spectral database of wood samples for their identification. The factors with the most significant effect on the hydrothermal modification were tannic acid and inorganic Fe3O2 salt, used as an additive. The results indicated the suitability of inorganic Fe3O2 salt and tannic acid combination applied in this type of modification, because a higher concentration of iron was distributed on the inner and intermediate sublayers of wood samples. The hydrothermal modification approach to anchor tannic acid–Fe macromolecules in wood shown in this study has promising capabilities and may attract interest in the field of wood protection against weathering.
This study used high-pressure extraction to obtain antioxidant-rich fractions from Desmodium canadense leaves harvested at five vegetation phases (intensive growing to end of blooming) and to evaluate their antioxidant activity and phytochemical profile. Supercritical CO2 extraction recovered lipophilic compounds, with the highest yield at massive flowering. The remaining plant material was fractionated by pressurized liquid extraction (PLE) using acetone, ethanol, and water; the highest PLE yield was achieved with water (16.54 g/100 g DW) at the bud formation stage. Antioxidant capacity was measured using total phenolic content (TPC) and ABTS•+, CUPRAC, and ORAC assays. Overall, ethanol PLE extracts showed the strongest antioxidant properties: maximum TPC (282.1 mg GAE/gE) and ABTS•+ (1010 mg TE/gE) at massive flowering, and highest CUPRAC (853.3 mg TE/gE) and ORAC (1882 mg TE/gE) at bud formation. UPLC-Q-TOF-MS/MS profiling identified 37 compounds, mainly C-glycosyl flavones, flavonol O-glycosides, hydroxycinnamic acid derivatives, and low molecular weight organic acids. Water extracts were rich in low molecular weight organic acids, while acetone and ethanol extracts contained the highest flavonoid levels. Citric acid and vitexin were the most abundant compounds. The findings indicate that D. canadense leaves, especially harvested at budding through massive flowering, are a promising source of flavonoid-rich antioxidant extracts for nutraceutical and functional food applications.