Multi-response optimal hot pressurized liquid recovery of extractable polyphenols from leaves of maqui (Aristotelia chilensis [Mol.] Stuntz)

Phenolics of Maqui Leaf Residues Exhibit Antioxidant Properties Against Ozone-Induced Oxidation in Fish Model Systems

Growing concern about food quality and safety has driven the search for natural food additives. Furthermore, maqui leaf residue (MLR), recovered from infusions that have long been part of traditional Chilean herbal medicine, still conserves a high content of phenolic compounds. The aim of this study was to optimize the ultrasound-assisted extraction (UAE) of phenolics from MLR and evaluate their potential effect on salmon preservation. The optimized parameters for UAE (6 min, MLR:Water = 1:30, and 70 W), obtained by using a Box-Behnken design, rendered the highest total phenolic content and antioxidant capacity. Furthermore, UAE showed a higher concentration of phenolic compounds compared to conventional extraction techniques, as evaluated by UPLC-ESI-MS/MS. The salmon with MLR had up to four times lower levels of thiobarbituric acid reactive substances, induced by ozonated water treatment, than the sample without this natural antioxidant. Moreover, MLR exhibited similar or superior effectiveness compared to synthetic antioxidants, such as butylated hydroxyanisole (BHA), 3,5-Di-tert-4butylhydroxytoluene (BHT). This study highlights the use of short-time aqueous ultrasound extraction as an environmentally friendly technology that allows the recovery of phenolic compounds from MLR, with potential application as a natural preservative that may replace or decrease the use of BHA and/or BHT.

Sustainable Recovery of Phlorotannins from Durvillaea incurvata: Integrated Extraction and Purification with Advanced Characterization

The rising demand for bioactive compounds from marine resources highlights the need for sustainable separation technologies. This study introduces an integrated process combining ultrasound-assisted extraction (USAE) and resin purification (RP) to isolate phlorotannins from Durvillaea incurvata, a brown seaweed with significant biomedical potential. Using a 32.5% ethanol-water solvent system for USAE followed by RP on Diaion HP-20 resin, phlorotannins were enriched 2.4-fold, with simultaneous removal of interfering compounds such as mannitol (~100%), which was demonstrated by FTIR and HPLC-IR analysis. Advanced characterization using UHPLC-QToF-MS/MS identified five novel phlorotannins with polymerization degrees of 3 to 8 phloroglucinol units in both USAE extracts and post-RP. Mass balance based on spectrophotometric measurements indicated a purification factor of ~2, confirming process effectiveness. RP streams showed distinct phlorotannin profiles, with one phlorotannin exceeding 70% relative abundance. However, MS/MS results showed significantly lower recoveries than spectrophotometric data, revealing a novel insight into RP purification. These findings highlight the critical role of comprehensive chemical characterization in optimizing sustainable phlorotannin extraction from seaweed. They propose a framework for scalable, eco-efficient technologies for achieving high-purity phlorotannin recovery. This approach facilitates the development of phlorotannin-based applications in the nutraceutical and pharmaceutical industries.

Comparative Analysis of Sustainable Extraction Methods and Green Solvents for Olive Leaf Extracts with Antioxidant and Antihyperglycemic Activities

Olive leaves are agro-industrial waste that pose an environmental management problem. However, they contain polyphenolic compounds with important bioactive properties beneficial to human. This study aimed to evaluate the effectiveness of two extraction technologies (pressurized liquid extraction and ultrasound-assisted extraction) combined with green solvents (pure water, 15% ethanol, and 15% glycerol) at 50 °C and 70 °C. The goal was to obtain extracts with both antioxidant capacity and antihyperglycemic properties from olive leaves. Pressurized liquid extraction with 15% glycerol at 70 °C was the most effective method for obtaining extracts rich in total polyphenols (19.46 mg GAE/g dw), with an antioxidant capacity of 4.11 mg/mL (inhibition capacity: IC50) and 500.26 µmol TE/g dw. For both extraction methods at 70 °C, glycerol was more effective at recovering phenolic acids, stilbenes and secoiridoid; while ethanol was more effective for recovering flavonols and phenylethanoids. Oleuropein was the most important polyphenol extracted from both pressurized liquid and ultrasound-assisted extractions, with concentrations of 171.48 µg/g dw and 246.70 µg/g dw, respectively. The extract obtained from pressurized liquid extraction with 15% ethanol at 70 °C exhibited significant inhibition (70%) of α-glucosidase enzymes, similar to the reference drug acarbose. In contrast, these extracts showed low inhibitory activity against the α-amylase enzyme. These findings can be applied to the development of functional foods and nutraceutical supplements aimed at managing postprandial glycemic response, offering a natural alternative for supporting type 2 diabetes management.

Optimization of Oil and Tocopherol Extraction from Maqui (Aristotelia chilensis (Mol.) Stuntz) by Supercritical CO2 Procedure

This study focused on the oil extraction from freeze-dried maqui (Aristotelia chilensis) by supercritical fluid extraction with carbon dioxide (SFE-CO2). The basic objective was to optimize the oil yield and the tocopherol concentration. A Box/Behnken experimental design was developed with three processing variables: supercritical pressure (74, 187, and 300 bar), temperature (35, 48, and 60 °C), and extracting time (30, 135, and 240 min). Multiple optimizations, based on the combination of factor levels at 274 bar, 240 min, and 60 °C, led to the highest oil yield and tocopherol values. The validation of the optimized conditions of maqui oil extraction led to an oil yield of 8% and values of 735, 53, and 97 (mg·kg-1 oil) for α-tocopherol, α-tocotrienol, and γ-tocopherol, respectively. A higher concentration of tocopherol compounds was observed when compared to the employment of the conventional extracting method. The optimized SFE-CO2 method led to an oil extract exhibiting higher Hydrophilic-Oxygen Radical Absorbance Capacity (H-ORAC) assay and total phenol content (22 μmol Trolox equivalents·g-1 oil and 28 mg gallic acid equivalents·g-1 oil) than the oil obtained by the conventional procedure. A practical and accurate oil extraction is proposed for obtaining tocopherol-enriched oil including high concentrations of valuable lipophilic antioxidants.

Exploring a Sustainable Process for Polyphenol Extraction from Olive Leaves

Olive leaves are residues from pruning and harvesting and are considered an environmental management problems. Interestingly, these residues contain high polyphenol concentrations, which can be used to treat chronic diseases. However, these compounds are a technological challenge due to their thermolability and reactivity during extraction. Thus, this study assessed the use of pressurized liquid extraction (PLE) with green solvents like water-ethanol and water-glycerol mixtures (0-15%) at 50 °C and 70 °C to yield polyphenol-rich antioxidant extracts with reduced glucose and fructose content. The use of 30% ethanol at 70°C presented the highest polyphenol content (15.29 mg gallic acid equivalent/g dry weight) and antioxidant capacity, which was expressed as IC50 (half maximal inhibitory concentration): 5.49 mg/mL and oxygen radical absorbance capacity (ORAC): 1259 μmol Trolox equivalent/g dry weight, as well as lower sugar content (glucose: 3.75 mg/g dry weight, fructose: 5.68 mg/g dry weight) compared to water-glycerol mixtures. Interestingly, ethanol exhibits a higher degree of effectiveness in recovering flavanols, stilbenes and secoiridoids, while glycerol improves the extraction of phenolic acids and flavonols. Therefore, to enhance the efficiency of polyphenol recovery during the PLE process, it is necessary to consider its solvent composition and chemical structure.

Antioxidant Properties of Maqui Berry Extract (Aristotelia chilensis (Mol.) Stuntz) and Its Potential Photoprotective Role on Human Skin Fibroblasts

Maqui berry (Aristotelia chilensis) is characterized by antioxidant and anti-inflammatory properties. The aim of this study was to evaluate the effect of maqui berry extracts on human skin fibroblasts (NHSFs) exposed to ultraviolet radiation (UVB). The photoprotective properties of the extracts were investigated via the determination of the total polyphenolic content (TPC) and antioxidant capacity (DPPH), and the chemical composition was assessed. The chemical purity of the extracts was studied via the evaluation of the toxic elements level. The water extract (MWE 57.75 ± 0.44 mg GAE/g) had the highest mean polyphenol content. The water (MWE) and ethanol (MEE70) extracts had the highest inhibitory activities against DPPH radical formation (283.63 ± 7.29 and 284.60 ± 4.31 mg Tx/L, respectively). The analyzed extracts were found to be safe in terms of toxic elements (arsenic, cadmium, lead). The tested extracts of maqui berry did not cause a cytotoxic effect on NHSF cells after 24, 48, and 72 h of incubation. When the NHSF cells were exposed to UVB radiation in the presence of maqui extracts, their viability was increased or maintained. The maqui berry extracts had a slightly protective effect against skin damage caused by UVB radiation. These were preliminary studies that require further research to determine which maqui compounds correspond with the photoprotective activity.

High-Yield Recovery of Antioxidant Compounds from Bambusa chungii Culms Using Pressurized Hot Water Extraction

A large amount of waste from Bambusa chungii culms is generated from the bamboo pulping industry, causing disposal problems. Nevertheless, bamboo culms are a suitable source of functional ingredients, such as antioxidant compounds. However, because of the high compactness and tightness in their material structure, obtaining phytochemicals from bamboo culms using conventional organic solvent extraction methods can be inefficient. In this research, we developed a pressurized hot water extraction (PHWE) method to recover 19 target phenolic compounds from Bambusa chungii culms. The extracted compounds were determined by ultra-high performance liquid chromatography-quadrupole time-of-flight-mass spectrometry (UPLC-QTOF-MS). The antioxidant potential of the extracts was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and ferric reducing antioxidant power (FRAP) assays. We investigated the effects of temperature, extraction time, and the material-to-liquid ratio on PHWE, and these parameters were optimized with a Box-Behnken design experiment and response surface tool. The optimal extraction condition was found at 170 °C, with a 1:30 g/mL material-to-liquid ratio and a 14 min extraction time. Following these optimal parameters, the total yield of target phenolic compounds (TYPC) reached 3.85 mg/g of raw material, and the half-maximal inhibitory concentrations (IC50) for the DPPH and ABTS tests were 94.7 mg/L and 21.88 mg/L, respectively. The FRAP value was 1.23 μmol FSE/mg of dried extract. A strong correlation between TYPC and the antioxidant activity of the extract was confirmed. The TYPC and antioxidant capacity of the optimal PHWE extract of the Bambusa chungii culms were both considerably higher than those of extracts obtained from conventional solvent extractions. These results indicated that PHWE is an excellent green technique for recovering phenolic compounds from bamboo culms, and the PHWE extracts of Bambusa chungii culms may be a good source of natural antioxidants.

Evaluation of Activity of Sesquiterpene Lactones and Chicory Extracts as Acetylcholinesterase Inhibitors Assayed in Calorimetric and Docking Simulation Studies

The aim of the study was to explain the effects of sesquiterpene lactones (SLs) from chicory (Cichorium intybus L.) root extracts as inhibitors of acetylcholinesterase (AChE) at the molecular level and to determine the inhibition of AChE activity by specific SLs (lactucin and lactucopicrin) and different chicory extracts. The obtained SLs-rich extracts were purified by the countercurrent partition chromatography (CPC) technique. AChE inhibitors were analyzed using two models: isothermal titration calorimetry (ITC) and docking simulation. The results of ITC analysis of the enzyme and the ligands' complexation showed strong interactions of SLs as well as extracts from chicory with AChE. In a test of enzyme activity inhibition after introducing acetylcholine into the model system with SL, a stronger ability to inhibit the hydrolysis of the neurotransmitter was observed for lactucopicrin, which is one of the dominant SLs in chicory. The inhibition of enzyme activity was more efficient in the case of extracts, containing different enzyme ligands, exhibiting complementary patterns of binding the AChE active site. The study showed the high potential of using chicory to decrease the symptoms of Alzheimer's disease.

Comparative Study of Metabolomic Profile and Antioxidant Content of Adult and In Vitro Leaves of Aristotelia chilensis

This work aimed to identify the bioactive compounds present in adult maqui (Aristotelia chilensis) leaves from different stages of development and seasons of the year and compare them with leaves obtained from maqui plants grown in vitro. The qualitative and quantitative analysis of maqui leaf extracts by HPLC-DAD-ESI-MSn showed the presence of different polyphenolic compounds classified into galloyl and caffeoyl quinic acids, ellagitannins and ellagic acid- and flavonoid-derivatives. In general, the total phenolic content of the in vitro samples was higher than that of ex vitro samples, whereas the total flavonoid content was higher in winter basal leaves. Additionally, the analysis by HPLC-MS showed that the extract from spring basal leaves was enriched in quercetin, catechin, kaempferol and 3-caffeoyl quinic acids, while in the in vitro leaves extract, quercetin was not present. As regards lipophilic compounds identified by GC/MS, the samples of in vitro leaves showed a high presence of α-tocopherol and β-sitosterol. In contrast, the samples of adult leaves presented a hight level of linolenic and linoleic acids. These results suggest that maqui leaves could be an excellent source of antioxidants and lipophilic compounds for many industries, such as the nutraceutical and pharmaceutical industries.

Rivera-Tovar P, Sanz V, Ferreira-Anta T, Torres MD, Pérez-Correa JR, Domínguez H. Pressurized Hot Water Extraction and Bio-Hydrogels Formulation with Aristotelia chilensis [Mol.] Stuntz Leaves

Aristotelia chilensis is a plant rich in phenolics and other bioactive compounds. Their leaves are discarded as waste in the maqui berry industry. A new application of these wastes is intended by the recovery of bioactive compounds using pressurized hot water extraction with conventional or microwave heating. Both technologies have been selected for their green character regarding the type of solvent and the high efficiency in shorter operation times. Extractions were performed in the temperature range 140–200 °C with a solid/liquid ratio of 1:15 (w:w). The extracts’ total phenolic content, antioxidant capacity, and saccharides content obtained with both heating methods were measured. Additionally, the thermo-rheological properties of the gelling matrix enriched with these extracts were analyzed. Optimum conditions for lyophilized extracts were found with conventional heating, at 140 °C and 20 min extraction; 250.0 mg GAE/g dry extract and 1321.5 mg Trolox/g dry extract. Close to optimum performance was achieved with microwave heating in a fraction of the time (5 min) at 160 °C (extraction), yielding extracts with 231.9 mg GAE/g dry extract of total phenolics and antiradical capacity equivalent to 1176.3 mg Trolox/g dry extract. Slightly higher antioxidant values were identified for spray-dried extracts (between 5% for phenolic content and 2.5% for antioxidant capacity). The extracts obtained with both heating methods at 200 °C contained more than 20% oligosaccharides, primarily glucose. All the formulated gelling matrices enriched with the obtained extracts displayed intermediate gel strength properties. The tested technologies efficiently recovered highly active antioxidant extracts, rich in polyphenolics, and valuable for formulating gelling matrices with potential applicability in foods and other products.