Antioxidant phenolic compounds recovery from Mangifera indica L. by-products by supercritical antisolvent extraction

Supercritical Impregnation of Mangifera indica Leaves Extracts into Porous Conductive PLGA-PEDOT Scaffolds

Plant leaves, such as those from Mangifera indica, represent a potential utilization of waste due to their richness in bioactive compounds. Supercritical CO2 allows these compounds to be incorporated into various matrices by impregnation. Combined with its ability to generate polymeric scaffolds, it represents an attractive strategy for the production of biomedical devices. For this purpose, conjugated polymeric scaffolds of biodegradable PLGA (poly(lactic-co-glycolic acid)) and PEDOT:PSS (poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)), generated in situ by foaming, were employed for the supercritical impregnation of ethanolic mango leaves extract (MLE) in tissue engineering as a potential application. The extraction of MLE was performed by Enhanced Solvent Extraction. The effects of pressure (120-300 bar), temperature (35-55 °C), and depressurization rate (1-50 bar/min) on the physical/conductive properties and the impregnation of MLE were studied. The scaffolds have been characterized by liquid displacement, scanning electron microscope, resistance to conductivity techniques, measurements of impregnated load, antioxidant capacity and antimicrobial activity. Porosity values ranging 9-46% and conductivity values between 10-4-10-5 S/cm were obtained. High pressures, low temperatures and rapid depressurization favored the impregnation of bioactive compounds. Scaffolds with remarkable antioxidant activity were obtained (75.2-87.3% oxidation inhibition), demonstrating the ability to inhibit S. aureus bacterial growth (60.1 to 71.4%).

Inclusion of Natural Antioxidants of Mango Leaves in Porous Ceramic Matrices by Supercritical CO2 Impregnation

Mango is one of the most important, medicinal tropical plants in the world from an economic point of view due to the presence of effective bioactive substances as co-products in its leaves. The aim of this work was to enhance the impregnation of natural antioxidants from mango leaves into a porous ceramic matrix. The effects of pressure, temperature, impregnation time, concentration of the extract and different porous silica on impregnation of phenolic compounds and antioxidant activity were analyzed. The volume of the pressurized fluid extract and amount of porous ceramic matrix remained constant. The best impregnation conditions were obtained at 6 h, 300 bar, 60 mg/mL, 35 °C and with MSU-H porous silica. The results indicated that increasing the pressure, concentration of the extract and temperature during impregnation with phenolic compounds such as gallic acid and iriflophenone 3-C (2-O-p-hydroxybenzolyl)-β-D-glucoside increased the antioxidant activity and the amount of total phenols.

Supercritical Antisolvent Technique for the Production of Breathable Naringin Powder

Flavonoids are polyphenolic compounds largely present in fruits and vegetables possessing antioxidant properties, anti-inflammatory and antibacterial activities. Their use in clinical practice is very poor due to their low bioavailability, susceptibility to oxidation and degradation. Moreover, their slight solubility in biological fluids and a consequent low dissolution rate leads to an irregular absorption from solid dosage forms, even though, anti-inflammatory formulations could be used as support for several disease treatment, i.e. the COVID-19 syndrome. To improve flavonoid bioavailability particle size of the powder can be reduced to make it breathable and to promote the absorption in the lung tissues. Supercritical fluid based antisolvent technique has been used to produce naringin particles, with size, shape and density as well as free flowing properties able to fit inhalation needs. The dried particles are produced with the removal of the solvent at lower temperatures compared to the most used traditional micronization processes, such as spray drying. The best breathable fraction for naringin particles is obtained for particles with a d₅₀~7 µm manufactured at 35 °C-150 bar and at 60 °C-130 bar, corresponding to 32.6% and 36.7% respectively. The powder is produced using a high CO₂ molar fraction (0.99) that assure a better removal of the solvent. NuLi-1 cell line of immortalised bronchial epithelial cells adopted to evaluate powder cytotoxicity indicated after 24 h absence of toxicity at concentration of 25 µM.

Carbon dioxide expanded liquid: an effective solvent for the extraction of quercetin from South African medicinal plants

BACKGROUND

Quercetin is one of the most important bioflavonoids having positive effects on the biological processes and human health. Typically, it is extracted from plant matrices using conventional methods such as maceration, sonication, infusion, and Soxhlet extraction with high solvent consumption. Our study aimed to optimize the environmentally friendly carbon dioxide-based method for the extraction of quercetin from quince fruit with an emphasis on extraction yield, repeatability, and short extraction time.

RESULTS

A two-step design of experiments was used for the optimization of the key parameters affecting physicochemical properties, including CO₂/co-solvent ratio, co-solvent type, temperature, and pressure. Finally, gas expanded liquid combining CO₂/ethanol/H₂O in a ratio of 10/81/9 (v/v/v) provided the best extraction yield. Extraction temperature 66 °C and pressure 22.3 MPa were the most suitable conditions after careful optimization, although both parameters did not significantly affect the process. It was confirmed by experiments in various pressure and temperature conditions and statistical comparison of obtained data. The optimized extraction procedure at a flow rate of 3 mL/min took 30 min. The repeatability of the extraction method exhibited an RSD of 20.8%.

CONCLUSIONS

The optimized procedure enabled very fast extraction in 30 min using environmentally friendly solvents and it was successfully applied to 16 different plant samples, including 14 bulbs and 2 fruits from South Africa. The quercetin content in extracts was quantified using ultra-high performance liquid chromatography (UHPLC) with tandem mass spectrometry. UHPLC hyphenated with high-resolution mass spectrometry was used to confirm chemical identity of quercetin in the analyzed samples. We quantified quercetin in 11 samples of all 16 tested plants. The quercetin was found in Agapanthus praecox from the Amaryllidaceae family and its presence in this specie was reported for the first time.

Croton lechleri Extracts as Green Corrosion Inhibitors of Admiralty Brass in Hydrochloric Acid

Croton lechleri, commonly known as Dragon’s blood, is a tree cultivated in the northwest Amazon rainforest of Ecuador and Peru. This tree produces a deep red latex which is composed of different natural products such as phenolic compounds, alkaloids, and others. The chemical structures of these natural products found in C. lechleri latex are promising corrosion inhibitors of admiralty brass (AB), due to the number of heteroatoms and π structures. In this work, three different extracts of C. lechleri latex were obtained, characterized phytochemically, and employed as novel green corrosion inhibitors of AB. The corrosion inhibition efficiency (IE%) was determined in an aqueous 0.5 M HCl solution by potentiodynamic polarization (Tafel plots) and electrochemical impedance spectroscopy, measuring current density and charge transfer resistance, respectively. In addition, surface characterization of AB was performed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy techniques. Chloroform alkaloid-rich extracts resulted in IE% of 57% at 50 ppm, attributed to the formation of a layer of organic compounds on the AB surface that hindered the dezincification process. The formulation of corrosion inhibitors from C. lechleri latex allows for the valorization of non-edible natural sources and the diversification of the offer of green corrosion inhibitors for the chemical treatment of heat exchangers.

Supercritical CO2 Extraction of Bioactive Compounds from Mango (Mangifera indica L.) Peel and Pulp

The potential of supercritical CO₂ (SC-CO₂) for the extraction of bioactive compounds from mango by-products was assessed. Carotenoid extraction was optimized using a design of experiments based on temperature (35, 55 and 70 °C), pressure (10 and 35 MPa) and co-solvent addition (0%, 10% and 20% of ethanol or acetone). Moreover, the co-extraction of phenolic acids, flavonoids and xanthonoids was evaluated in a subset of parameters. Finally, a comparison was made between SC-CO₂ and a two-step organic solvent extraction of the bioactive compounds from the pulp and peel fractions of two Ecuadorian varieties. The optimal extraction temperature was found to be dependent on the bioactive type, with phenolics requiring higher temperature than carotenoids. The optimal overall conditions, focused on maximal carotenoids recovery, were found to be 55 °C, 35 MPa and 20% of ethanol. The main carotenoid was β-carotene, while phenolics differed among the varieties. The bioactive content of the peel was up to 4.1-fold higher than in the pulp fraction. Higher antioxidant activity was found in the extracts obtained with organic solvents. SC-CO₂ is a promising technology for the isolation of valuable compounds from mango by-products.

The Application of Supercritical Fluids Technology to Recover Healthy Valuable Compounds from Marine and Agricultural Food Processing By-Products: A Review

Food by-products contain a remarkable source of bioactive molecules with many benefits for humans; therefore, their exploitation can be an excellent opportunity for the food sector. Moreover, the revalorization of these by-products to produce value-added compounds is considered pivotal for sustainable growth based on a circular economy. Traditional extraction technologies have several drawbacks mainly related to the consumption of hazardous organic solvents, and the high temperatures maintained for long extraction periods which cause the degradation of thermolabile compounds as well as a low extraction efficiency of desired compounds. In this context, supercritical fluid extraction (SFE) has been explored as a suitable green technology for the recovery of a broad range of bioactive compounds from different types of agri-food wastes. This review describes the working principle and development of SFE technology to valorize by-products from different origin (marine, fruit, vegetable, nuts, and other plants). In addition, the potential effects of the extracted active substances on human health were also approached.

In Vitro Gastrointestinal Digestion and Colonic Catabolism of Mango (Mangifera indica L.) Pulp Polyphenols

Mango (Mangifera indica L.), a fruit with sensorial attractiveness and extraordinary nutritional and phytochemical composition, is one of the most consumed tropical varieties in the world. A growing body of evidence suggests that their bioactive composition differentiates them from other fruits, with mango pulp being an especially rich and diverse source of polyphenols. In this study, mango pulp polyphenols were submitted to in vitro gastrointestinal digestion and colonic fermentation, and aliquots were analyzed by HPLC-HRMS. The main phenolic compounds identified in the mango pulp were hydroxybenzoic acid-hexoside, two mono-galloyl-glucoside isomers and vanillic acid. The release of total polyphenols increased after the in vitro digestion, with an overall bioaccessibility of 206.3%. Specifically, the most bioaccessible mango polyphenols were gallic acid, 3-O-methylgallic acid, two hydroxybenzoic acid hexosides, methyl gallate, 3,4-dihydroxybenzoic acid and benzoic acid, which potentially cross the small intestine reaching the colon for fermentation by the resident microbiota. After 48 h of fecal fermentation, the main resultant mango catabolites were pyrogallol, gallic and 3,4-dihydroxybenzoic acids. This highlighted the extensive transformation of mango pulp polyphenols through the gastrointestinal tract and by the resident gut microbiota, with the resultant formation of mainly simple phenolics, which can be considered as biomarkers of the colonic metabolism of mango.

Towards Green Nanoscience: From extraction to nanoformulation

The use of nanotechnology has revolutionized many biotechnological sectors, from bioengineering to medicine, passing through food and cosmetic fields. However, their clinic and industrial application has been into the spotlight due to their safety risk and related side effects. As a result, Green Nanoscience/Nanotechnology emerged as a strategy to prevent any associated nanotoxicity, via implementation of sustainable processes across the whole lifecycle of nanoformulation. Notwithstanding its success across inorganic nanoparticles, the green concept for organic nanoparticle elaboration is still at its infancy. This, coupled with the organic nanoparticles being the most commonly used in biomedicine, highlights the need to implement specific green principles for their elaboration. In this review, we will discuss the possible green routes for the proper design of organic nanoparticles under the umbrella of Green Nanoscience: from the extraction of nanomaterials and active compounds to their final nanoformulation.

A Glimpse into the Extraction Methods of Active Compounds from Plants

Naturally active compounds are usually contained inside plants and materials thereof. Thus, the extraction of the active compounds from plants needs appropriate extraction methods. The commonly employed extraction methods are mostly based on solid-liquid extraction. Frequently used conventional extraction methods such as maceration, heat-assisted extraction, Soxhlet extraction, and hydrodistillation are often criticized for large solvent consumption and long extraction times. Therefore, many advanced extraction methods incorporating various technologies such as ultrasound, microwaves, high pressure, high voltage, enzyme hydrolysis, innovative solvent systems, adsorption, and mechanical forces have been studied. These advanced extraction methods are often better than conventional methods in terms of higher yields, higher selectivity, lower solvent consumption, shorter processing time, better energy efficiency, and potential to avoid organic solvents. They are usually designed to be greener, more sustainable, and environment friendly. In this review, we have critically described recently developed extraction methods pertaining to obtaining active compounds from plants and materials thereof. Main factors that affect the extraction performances are tuned, and extraction methods are chosen in line with the properties of targeted active compounds or the objectives of extraction. The review also highlights the advancements in extraction procedures by using combinations of extraction methods to obtain high overall yields or high purity extracts.

Supercritical Carbon Dioxide Antisolvent Fractionation for the Sustainable Concentration of Lavandula luisieri (Rozeira) Riv.- Mart Antimicrobial and Antioxidant Compounds and Comparison with Its Conventional Extracts

Lavandula stoechas subsp. luisieri is a Spanish subspecies from the Lamiaceae family. Its essential oil has been traditionally used for several medical applications though little is known about other extracts. Similar to many other studies aiming to obtain traditional plant extracts to be used in different applications, this work evaluated the antioxidant and antimicrobial activities of Lavandula luisieri extracts and the correlation with their composition. Traditional hydrodistillation and ethanolic maceration were used to obtain the essential oil and the maceration extract, respectively. A green and sustainable methodology was applied to the maceration extract that was under a Supercritical Antisolvent Fractionation process to obtain a fine solid enriched in rosmarinic acid and the terpenes oleanolic and ursolic acids. Antimicrobial activities of all extracts and pure identified compounds (rosmarinic and ursolic acids) were evaluated against five bacterial strains; Listeria monocytogenes, Enterococcus faecium, Staphylococcus aureus, Salmonella Typhimurium and Escherichia coli and were compared with the pure compounds identified, rosmarinic and ursolic acids. All strains were sensitive against L. luisieri essential oil. The solid product obtained from the supercritical process was concentrated in the identified actives compared to the maceration extract, which resulted in higher antimicrobial and DPPH scavenging activities. The supercritical sustainable process provided L. luisieri compounds, with retention of their antimicrobial and antioxidant activities, in a powder exemptof organic solvents with potential application in the clinical, food or cosmetic fields.

LC-ESI-QTOF/MS Profiling of Australian Mango Peel By-Product Polyphenols and Their Potential Antioxidant Activities

Mango (Mangifera indica L.) is one of the most important fruits in the world. Mango peel is an important by-product that is rich in polyphenols and it could have high economic value if it is effectively utilized. Phenolic characterization is an essential step in the commercial utilization of mango peel by-products as food ingredients. Herein, qualitative and quantitative analyses of two Australian mango peel “Keitt” and “Kensington Pride” (K&P) by-products were conducted while using liquid chromatography coupled to electrospray ionisation and quadrupole time of flight mass spectrometry (LC-ESI-QTOF/MS) and high-performance liquid chromatography coupled to photodiode array detector (HPLC-PDA). A total of 98 polyphenols compounds were tentatively identified in both Keitt peel and K&P peel extracts, with greater concentrations of these compounds being detected in Keitt peel. The total phenolic content (TPC), total flavonoid content (TFC), and a total tannin content (TTC) were determined. The antioxidant activity of mango peel by-products was determined while using 2,2-diphenyl-1-picrylhydrazyl (DPPH) antioxidant assay, ferric reducing antioxidant power (FRAP) assay, and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging assay. Keitt peel contained higher concentrations of total phenolic compounds, flavonoids, and tannins and had higher antioxidant capacity in DPPH, FRAP, and ABTS assays as compared to K&P peel. In HPLC-PDA quantification, the predominant phenolic compounds in Keitt peel and K&P peel were catechin (62.32 ± 0.01 mg/gd.w.) and syringic acid (17.78 ± 0.01 mg/gd.w).

Ultrasound-Assisted Phytochemical Extraction Condition Optimization Using Response Surface Methodology from Perlette Grapes (Vitis vinifera)

In the current study, bioactive compounds of Vitis vinifera (Perlette) were extracted using an ultrasound-assisted extraction technique. The central composite design of response surface methodology (RSM) was used to determine the effect of time, temperature, and concentration of acetic acid on response variables that include extract yield, total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity of Vitis vinifera extracts. The results of the central composite design of RSM revealed that the quadratic polynomial model is best fitted to experimental results, with all the responses having a regression coefficient greater than 0.9. Optimized extraction levels include 26.5 min, an extraction temperature of 59 °C, and an acetic acid concentration of 62.9% with good extraction yield results of 34.95 g/100 g dry weight (DW) of grapes, TPC 34.38 mg gallic acid equivalent per gram (GAE/g) DW, flavonoid content 10.21 mg quercetin equivalents per gram (QEQ/g) DW, and antioxidant activity of 9.11 mg/100 mL ascorbic acid equivalent. The present study showed that acetic acid can be effectively used for the ultrasound-assisted extraction of polyphenols, flavonoids, and antioxidants of Vitis vinifera. These optimized conditions can be used for the extraction of bioactive compounds that can be for the development of nutraceutical products.

Mangifera indica L. Leaf Extract Induces Adiponectin and Regulates Adipogenesis

Natural bioactive compounds may be used in obese patients because of their ability to impact on various key mechanisms involved in the complex pathophysiological mechanisms of such condition. The aim of this study was to investigate the effect of a Mangifera indica L. leaf extract (MLE) on adipogenic differentiation of murine preadipocyte cells. 3T3-L1 cells were treated during their differentiation with various concentrations of (Mangifera indica L.) leaves extract (MLE) (750, 380, 150, 75 and 35 μg) in order to assess their lipid content, adiponectin production, expression profile of genes involved in lipid metabolism, oxidative stress and inflammation. Our results showed that MLE was particularly enriched in polyphenols (46.30 ± 0.083 mg/g) and that pharmacological treatment of cells resulted in a significant increase of adiponectin levels and reduction of intracellular lipid content. Consistently with these results, MLE resulted in a significant decrease of the expression of genes involved in lipid metabolism (FAS, PPARG, DGAT1, DGAT2, and SCD-1). In conclusion, our results suggest that MLE may represent a possible pharmacological tool for obese or metabolic syndrome patients.

Bioactive Compounds and Antioxidant Activity of Mango Peel Liqueurs (Mangifera indica L.) Produced by Different Methods of Maceration

The present work had the objective of producing liqueurs from mango peels (varieties "Haden" and "Tommy Atkins") by processes of alcoholic maceration and maceration with pectinase, as well as to evaluate bioactive compounds by reversed-phase high-performance liquid chromatography coupled to diode array detection and fluorescence-detection (RP-HPLC/DAD/FD) and in vitro antioxidant activity (AOX), for by-product potential reuse. Alcoholic maceration in wine ethanol (65% v/v) produced liqueurs with higher phytochemical and AOX content. Maceration with pectinase resulted in liqueurs with higher quercetin-3-O-glucopyranoside content. In relation to mango varieties, Haden liqueurs presented higher bioactive content than Tommy Atkins liqueurs. The liqueurs presented high antioxidant activity. The main bioactive compounds found were flavanols (epicatechin-gallate, epigallocatechin-gallate), flavonols (quercetin-3-O-glucopyranoside and rutin), and phenolic acids (gallic acid, o-coumaric acid, and syringic acid). The present study showed that the production of liqueur enabled the recovering of an important part of the bioactive content of mango peels, suggesting an alternative for the recovery of antioxidant substances from this by-product.

Supercritical anti-solvent fractionation for improving antioxidant and anti-inflammatory activities of an Achillea millefolium L. extract

Achillea millefolium L. is a plant widely used in traditional medicine. Nowadays, there is a growing concern about the study of its bioactive properties in order to develop food and nutraceutical formulations. Supercritical anti-solvent fractionation (SAF) of an A. millefollium extract was carried out to improve its antioxidant and anti-inflammatory activities. A selective precipitation of phenolic compounds was achieved in the precipitation vessel fractions, which presented an antioxidant activity twice than original extract, especially when fractionation was carried out at 10 MPa. The main phenolic components identified in this fraction were luteolin-7-O-glucoside, 3,5-dicaffeoylquinic acid, 6-hidroxyluteolin-7-O-glucoside and apigenin-7-O-glucoside. However, separator fractions presented higher anti-inflammatory activity than precipitation vessel ones, particularly at 15 MPa. This fact could be related to separator fractions enrichment in anti-inflammatory compounds, mainly camphor, artemisia ketone and borneol. Therefore, SAF produced a concentration of antioxidant and anti-inflammatory compounds that could be used as high-added valued ingredients.

Mango-bagasse functional-confectionery: vehicle for enhancing bioaccessibility and permeability of phenolic compounds

Study on bioaccessibility and absorption path of mango bagasse phenolics.

Interpenetration of Natural Polymer Aerogels by Supercritical Drying

Natural polymers, such as alginate and gelatin, can be used to produce scaffolds for tissue engineering applications; but, their mechanical and biochemical performance should be improved. A possible solution to obtain this result, is the generation of multi-component scaffolds, by blending two or more polymers. One way to realize it, is the formation of an interpenetrating polymer network (IPN). In this work, the interpenetration of alginate and gelatin hydrogels has been successfully obtained and preserved by supercritical CO₂ (SC-CO₂) drying performed at 200 bar and 35 °C, using different blend compositions: from alginate/gelatin = 20:80 v/v to alginate/gelatin = 80:20 v/v. The process allowed modulation of morphology and mechanical properties of these blends. The overall result was made possible by the supercritical drying process that, working at zero surface tension, allows preserving the hydrogels nanostructure in the corresponding aerogels.

Optimization of Ultrasound-Assisted Extraction of phenolic compounds and anthocyanins from blueberry (Vaccinium ashei) wine pomace

Ultrasound-Assisted Extraction (UAE) of total anthocyanins (TA) and phenolics (TP) from Blueberry Wine Pomace (BWP) was optimized using Response Surface Methodology (RSM). A Box-Behnken design was used to predict that the optimized conditions were an extraction temperature of 61.03°C, a liquid-solid ratio of 21.70mL/g and a sonication time of 23.67min. Using the modeled optimized conditions, the predicted and experimental yields of TA and TP were within a 2% difference. The yields of TA and TP obtained through the optimized UAE method were higher than those using a Conventional Solvent Extraction (CSE) method. Seven anthocyanins, namely delphinidin-3-O-glucoside, delphindin-3-O-arabinoside, petunidin-3-O-glucoside, cyanidin-3-O-arabinoside, cyanidin-3-O-glucoside, malvidin-3-O-glucoside and malvidin-3-O-arabinoside, were found in the BWP extract from both the UAE and CSE methods.