Recovery of lotus (Nelumbo nucifera Gaertn.) seedpod flavonoids using polar macroporous resins: The updated understanding on adsorption/desorption mechanisms and the involved intermolecular attractions and bonding

Purification of chicoric acid from dandelion herbal pieces using macroporous resin combined with HSCCC and its antioxidant capacity in human keratinocytes

Dandelion (Taraxacum mongolicum Hand. - Mazz.) is a traditional Chinese medicinal herb rich in active ingredients such as flavonoids and polyphenols, which are used to treat swelling and inflammation-related diseases. In the present study, total flavonoids and polyphenols in dandelion herbal pieces (Taraxaci Herba) extracts were purified by HPD-500 resin column chromatography, and the total flavonoid purity in purified extracts E80% was 5.3 times that of before purification, reaching 43.98 %. The purified extracts E80% were analyzed by UHPLC-QTOF-MS and 8 phenolic acid compounds were identified, including caffeic acid, chlorogenic acid, and chicoric acid. Moreover, high-speed countercurrent chromatography method was established to separate chicoric acid from E80%. n-hexane-ethyl acetate-methanol-0.5 % acetic acid in water (2:7:2:7, v/v/v/v) was selected as the solvent system. Chicoric acid with a purity of 95.44 % was obtained with the flow rate of 2.0 mL/min, the speed of 850 r/min, the system temperature of 35 °C and sample loading of 100 mg. In vitro bioassay showed that chicoric acid presented impressive antioxidant activities in SDS-induced human keratinocytes by promoting cell proliferation, increasing superoxide dismutase (SOD) activity, reducing the reactive oxygen species (ROS) level, stabilizing the mitochondrial membrane potential, and inhibiting cell apoptosis. Collectively, these results lay a theoretical basis for the industrial separation of natural antioxidant compounds.

Depolymerized peanut skin-derived proanthocyanidins alleviate cognitive dysfunction by inhibiting Aβ42 aggregation in Alzheimer's disease

Peanut skin proanthocyanidins (PSP) are natural polyphenols with antioxidant properties that mitigate Alzheimer's disease (AD), a complex progressive neurodegenerative disorder whose underlying biological mechanisms includes the aggregation of insoluble amyloid plaques. However, the high degree of polymerization of PSP, extracted using conventional methods, limits its bioavailability. This study established the optimal processes for ultrasound-assisted alkaline depolymerization to produce oligomeric proanthocyanidins (OPSP) from PSP content (2.7 mg/mL), depolymerization temperature (54.8 °C), ultrasonic power (480 W, 28 Hz), ultrasonic duration (28.7 min), and pH (12.1). Under these conditions, the degree of polymerization of the proanthocyanidins decreased from 6.74 to 2.87. Physicochemical characteristics of PSP and OPSP were analyzed. Both PSP and OPSP exhibited shared structural bonding and a repeating 288 Da unit, with Proanthocyanidin A identified as the predominant type. Furthermore, compared with PSP, OPSP demonstrated enhanced stability and antioxidant activity. Using in vitro detection of amyloid-beta (Aβ42) inhibition, this study demonstrated that OPSP exhibited greater inhibition of Aβ42 fibrillogenicity than underpolymerized PSP, and OPSP significantly inhibited Aβ42-induced cytotoxicity. In addition, the effect of OPSP was investigated in a rat model of Alzheimer's disease. The results indicated that OPSP improved the memory performance of AD rats in the water maze and decreased the levels of inflammatory factors IL-6, IL-1β, and TNF-α. Moreover, OPSP ameliorated histopathological changes and reduced Aβ42 plaque deposition in the brains of AD rats. These findings regarding OPSP are anticipated to facilitate high-value utilization of peanut by-products, expand their applications, and provide guidance for the use of OPSP in the development of natural healthcare pharmaceuticals and mitigation and treatment of Alzheimer's disease.

Macroporous resins combined with UPLC-QTRAP-MS/MS for the purification and identification of 3-deoxyanthocyanidins from Sorghum bicolor L. Moench and their bioactivities

3-Deoxyanthocyanidins (3-DAS) are the unique flavonoid compounds in sorghum. The majority of research to date have concentrated on the biological activity and extraction of 3-DAS from sorghum and lacked systematic purification and identification investigations. Herein, a facile method for the purification of sorghum 3-DAS from the acidic methanol solution crude extract using macroporous resins (MARs) was proposed and investigated in this work. Based on the experimental data, commercial MAR AB-8 was selected to achieve the purification of sorghum 3-DAS. The adsorption-desorption experiment confirmed the optimal procedure. With this procedure, the total purity of 3-DAS was 19.32%, and 3-DAS content in the purified product was 8.4 times higher than that in the crude extract. UPLC-QTRAP-MS/MS identification indicated that the purified 3-DAS product was mainly composed of apigeninidin, luteolinidin, and their methoxy derivatives. Besides, the purified product exhibited better bioactivities than the crude extract, including the scavenging activities for DPPH, ABTS+, and hydroxyl radicals, the total antioxidant capacity, and the inhibitory effects for α-amylase, α-glucosidase, and lipase. This work provides a potential way for the large-scale purification of bioactive sorghum 3-DAS from crude extract, which is significant to deepen the applications of sorghum 3-DAS in the food nutrition and pharmaceutical industries.

Profiling the chemical properties of Foeniculum vulgare Mill. and its flavonoids through comprehensive LC-MS/MS to evaluate their anti-motion sickness effect

Foeniculum vulgare Mill. is a medicinal and food homologous plant, and it has various biological activities. Yet, no research has explored its anti-motion sickness effects. Chemical properties of fennel extracts (FvE) and flavonoids (Fvf) were analyzed based on UPLC-QTRAP-MS to elucidate its potential anti-motion sickness components in the present study. The mice models of motion sickness were stimulated by biaxial rotational acceleration. Behavioral experiments such as motion sickness index and open field test and the measurement of neurotransmitters were used to evaluate the efficacy of compounds on motion sickness. Results showed that FvE contains terpenes, alkaloids, flavonoids, etc. Eight flavonoids including quercetin-3β-D-glucoside, rutin, hyperoside, quercetin, miquelianin, trifolin, isorhamnetin and kaempferol were identified in the purified Fvf. FvE and Fvf significantly reduced the motion sickness index of mice by 53.2% and 48.9%, respectively. Fvf also significantly alleviated the anxious behavior of mice after rotational stimulation. Among the eight flavonoids, isorhamnetin had the highest oral bioavailability and moderate drug-likeness index and thus speculated to be the bioactive compound in fennel for its anti-motion sickness effect. It reduced the release of 5-HT and Ach to alleviate the motion sickness response and improve the work completing ability of mice and nervous system dysfunction after rotational stimulation. This study provided in-depth understanding of the anti-motion sickness bioactive chemical properties of fennel and its flavonoids, which will contribute to the new development and utilization of fennel.

Precise evaluation of batch adsorption kinetics of plant total polyphenols based on a flow-injection online spectrophotometric method

Efficient evaluation of adsorption kinetics of plant total polyphenols is essential for the design of adsorption separation of bioactive compounds. The conventional method uses manual sampling with poor reproducibility. Here, we developed a new method for on-line determination of total polyphenol content (TPC) in plant extracts by applying the Folin-Ciocalteu method in flow-injection analysis (FIA). The FIA parameters were optimized and a standard curve with excellent linearity was established. Precise determination of TPC with a satisfactory sample throughput of 20 h-1 was achieved for the adsorption kinetic study. The pseudo-second-order kinetic model was found to better describe the kinetic parameters of the batch adsorption/desorption process. The developed method proved to be accurate compared with the conventional method. The FIA method holds significant promise for studying and monitoring adsorption processes, due to its automatic on-line nature, low consumption of reagents and samples, and the ability to generate large quantities of highly accurate adsorption data.

An integrated process by ultrasonic enhancement in the deep eutectic solvents system for extraction and separation of chlorogenic acid from Eucommia ulmoides leaves

This study established an integrated process for the extraction and enrichment of chlorogenic acid(CGA)from Eucommia ulmoides leaves in a deep eutectic solvent system via ultrasonic wave-enhanced adsorption and desorption practices utilizing macroporous resins. Although deep eutectic solvents (DESs) have the advantages of chemical stability, good dissolving capacity, and nonvolatilization, routine solvent recovery operations are not suitable for subsequent separation in this solvent system. Based on the above characteristics, this study integrated the extraction and enrichment processes, in which DESs extracts directly loaded onto the macroporous adsorption resin, avoiding the loss of target components in solvent recovery and redissolution processes. The screening results of solvents and resin types further showed that choline chloride-malic acid (1:1) was the optimal DES, and the NKA-II resin had high adsorption and elution performance for CGA. The viscosities of the DESs were much higher than those of water and conventional organic solvents; thus, the mass transfer resistance was large, which could also affect the adsorption behaviour of the macroporous resin. The thermal and mechanical effects of ultrasound could effectively enhance the efficiency of the mass transfer, adsorption, and desorption in the DES systems. When compared to no sonication treatment, the CGA adsorption at various ultrasonic powers (120-600 W) was examined. At optimal ethanol concentration (60%), the effect of the ultrasonic treatment on the recovery of the DESs (water eluting process) and the desorption capability of CGA were confirmed. The use of three volumes of water elution could recover the DESs without loss of CGA. The adsorption process significantly differed depending on the ultrasonic settings, and the absorption balance time and experimental adsorption capacity at equilibrium were enhanced. Additionally, the adsorption procedure of the NKA-II macroporous resin for CGA under ultrasonic treatment could be clarified by the pseudo second order kinetic equation and the Freundlich isotherm model. Thermodynamic and dynamic parameters indicated that physical adsorption was the main process of the entire procedure, and it was a spontaneous, exothermic, and entropy-reducing physical adsorption process. This study potentially indicates that the use of ultrasonication, as a high-efficiency, environmentally friendly method, can enhance the features of the macroporous resin to better purify target chemicals from a DES extract.

Rapid extraction of bioactive compounds from gardenia fruit using new and recyclable deep eutectic solvents

The utilization of deep eutectic solvent as an alternative and environmentally friendly option has gained significant attention. This study first proposed a series of benzylammonium chloride based-deep eutectic systems for the extraction of bioactive compounds from Gardenia jasminoides Ellis. Through the implementation of response surface methodology, the optimal solvent was determined to be dodecyldimethylbenzylammonium chloride-levulinic acid (1:3, mol/mol) with 35% (v/v) water, specifically tailored to extract geniposide, genipin-1-β-d-gentiobioside, crocin-1, and crocin-2 from gardenia fruits with the ratio of solid to liquid of 1:20 at 86°C for 16 min. Their total extraction yields could reach 70.6 mg/g, outperforming those obtained by other solvents and corresponding techniques. Furthermore, the eutectic system was retrieved after first-cycle extraction, and then applied in the subsequent extraction progress, yielding a consistent extraction efficiency of 97.1%. As compared to previous traditional methods, a quick, high-yielding, and green extraction procedure was achieved through simple heating settings that did not constrain the instrument. Therefore, dodecyldimethylbenzylammonium chloride-levulinic acid could serve as a sustainable and reusable solvent for efficient extraction of natural bioactive compounds from plant-based raw materials. The application of deep eutectic solvents has demonstrated their potential as designable solvents with stronger extraction capabilities than traditional organic solvents.

Recent advances on bioactive compounds, biosynthesis mechanism, and physiological functions of Nelumbo nucifera

Nelumbo nucifera Gaertn, commonly known as lotus, is a genus comprising perennial and rhizomatous aquatic plants, found throughout Asia and Australia. This review aimed to cover the biosynthesis of flavonoids, alkaloids, and lipids in plants and their types in different parts of lotus. This review also examined the physiological functions of bioactive compounds in lotus and the extracts from different organs of the lotus plant. The structures and identities of flavonoids, alkaloids, and lipids in different parts of lotus as well as their biosynthesis were illustrated and updated. In the traditional medicine systems and previous scientific studies, bioactive compounds and the extracts of lotus have been applied for treating inflammation, cancer, liver disease, Alzheimer's disease, etc. We suggest future studies to be focused on standardization of the extract of lotus, and their pharmacological mechanisms as drugs or functional foods. This review is important for the lotus-based food processing and application.

Phytochemicals, biological activity, and industrial application of lotus seedpod (Receptaculum Nelumbinis): A review

Lotus (Nelumbo nucifera Gaertn.) is a well-known food and medicinal plant. Lotus seedpod (Receptaculum Nelumbinis) is the by-products during lotus products processing, which is considered as waste. Numerous studies have been conducted on its phytochemicals, biological activity and industrial application. However, the information on lotus seedpod is scattered and has been rarely summarized. In this review, summaries on preparation and identification of phytochemicals, the biological activities of extracts and phytochemicals, and applications of raw material, extracts and phytochemicals for lotus seedpod were made. Meanwhile, the future study trend was proposed. Recent evidence indicated that lotus seedpods extracts, obtained by non-organic and organic solvents, possessed several activities, which were influenced by extraction solvents and methods. Lotus seedpods were rich in phytochemicals categorized as different chemical groups, such as proanthocyanidins, oligomeric procyanidins, flavonoids, alkaloids, terpenoids, etc. These phytochemicals exhibited various bioactivities, including ameliorating cognitive impairment, antioxidation, antibacterial, anti-glycative, neuroprotection, anti-tyrosinase and other activities. Raw material, extracts and phytochemicals of lotus seedpods could be utilized as sources for biochar and biomass material, in food industry and as dye. This review gives well-understanding on lotus seedpod, and provides theoretical basis for its future research and application.

Optimization of Ultrasound-Assisted Cellulase Extraction from Nymphaea hybrid Flower and Biological Activities: Antioxidant Activity, Protective Effect against ROS Oxidative Damage in HaCaT Cells and Inhibition of Melanin Production in B16 Cells

In this study, ultrasonic-assisted cellulase extraction (UCE) was applied to extract flavonoids and polyphenols from the Nymphaea hybrid flower. The extraction conditions were optimized using the response surface method (RSM) coupled with a Box-Behnken design. The crude extract of Nymphaea hybrid (NHE) was further purified using AB-8 macroporous resins, and the purified extract (NHEP) was characterized by FTIR and HPLC. In vitro activity determination by chemical method showed that NHEP displayed strong free radical scavenging abilities against the DPPH and ABTS radicals, good reduction power, and hyaluronidase inhibition. The cell viability by CCK-8 assays showed that NHEP had no significant cytotoxicity for B16 and HaCaT cells when the concentration was below 100 μg/mL and 120 μg/mL, respectively. NHEP with a concentration of 20–160 μg/mL can more effectively reduce the ROS level in H₂O₂ damaged HaCaT cells compared with 10 μg/mL of VC. The 40 μg/mL of NHEP had similar activity against intracellular melanin production in the B16 melanoma cells compared with 20 μg/mL Kojic acid. Good activities of antioxidation, whitening and protective effect against H₂O₂-induced oxidative damage promote the potential for NHEP as a functional raw material in the field of cosmetics and medicine.

Ultrasound-assisted adsorption/desorption of jujube peel flavonoids using macroporous resins

The work explored the process of ultrasound-assisted adsorption/desorption to efficiently purify jujube peel flavonoids (JPFs) using macroporous resins (MRs). The impact of ultrasound power and temperature on the adsorption/desorption features of JPFs on MRs were studied. The maximum adsorption (80.21 ± 2.11 mg/g) /desorption (76.22 ± 1.68 mg/g) capacity of total flavonoids content were obtained. The pseudo-second-order kinetic and Freundlich isotherm models better described the whole process of ultrasound-assisted adsorption. The adsorption process was spontaneous, physical, and dominated by multilinear intraparticle diffusion. Ultrasound mainly enhanced the adsorption capacity by strengthening the formation of hydrogen bonds and increasing the surface roughness of MRs. Besides, the principal individual flavonoid ((+)-Catechin, (-)-Epicatechin, Rutin, Quercetin-3-O-robinobioside) content of JPFs in ultrasound treatment was 2-3 times that of shaking treatment, and biological activities were significantly increased. Overall, as a low-cost green technology, ultrasound can improve the properties of MRs and better purify JPFs.

Procyanidins: From Agro-Industrial Waste to Food as Bioactive Molecules

Procyanidins are an important group of bioactive molecules known for their benefits to human health. These compounds are promising in the treatment of chronic metabolic diseases such as cancer, diabetes, and cardiovascular disease, as they prevent cell damage related to oxidative stress. It is necessary to study effective extraction methods for the recovery of these components. In this review, advances in the recovery of procyanidins from agro-industrial wastes are presented, which are obtained through ultrasound-assisted extraction, microwave-assisted extraction, supercritical fluid extraction, pressurized fluid extraction and subcritical water extraction. Current trends focus on the extraction of procyanidins from seeds, peels, pomaces, leaves and bark in agro-industrial wastes, which are extracted by ultrasound. Some techniques have been coupled with environmentally friendly techniques. There are few studies focused on the extraction and evaluation of biological activities of procyanidins. The identification and quantification of these compounds are the result of the study of the polyphenolic profile of plant sources. Antioxidant, antibiotic, and anti-inflammatory activity are presented as the biological properties of greatest interest. Agro-industrial wastes can be an economical and easily accessible source for the extraction of procyanidins.

Ultrasound aided debittering of bitter variety of citrus fruit juice: Effect on chemical, volatile profile and antioxidative potential

In the present study, sonication assisted debittering of pomelo fruit juice was carried out and the effect of sonication along with resin/enzyme on the chemical, phytochemical and volatile composition of juice was also investigated. The optimum conditions for sonication coupled debittering using resin were 50 kHz, 2 min, and 45 ℃ while 50 kHz, 60 min, and 60 ℃ were obtained for enzyme hydrolysis. Sonication treatment not only reduced the debittering time but also enhanced the adsorption and hydrolysis of naringin by 17% and 20% in resin and enzyme respectively. In addition, enzymatic activity was also improved and weakened C-O bonds in naringin. At the same time, sonication significantly affected the bioactive compounds of juice, chemical composition, and volatile compounds of juice. Flavor compounds including octanal, linalool, citral, and ethyl butyrate were enhanced by sonication-assisted enzymatic treated juice.

Efficient enrichment of total flavonoids from kale (Brassica oleracea L. var. acephala L.) extracts by NKA-9 resin and antioxidant activities of flavonoids extract in vitro

This work established an effective method for kale flavonoids enrichment by resins. Resin screening, adsorption kinetics and isotherms, dynamic adsorption and desorption tests were conducted to optimize the appropriate resins and enrichment conditions. The results showed that NKA-9 was the optimum resin. The best adsorption conditions were 0.2 mg/mL flavonoids concentration, 12.5 bed volume (BV) sample volume and 2 BV/h adsorption rate. The desorption conditions were 3 BV of 80% ethanol at 2 BV/h elution rate. Under these conditions, the product purity was 31.16%. The purified flavonoids extract was mainly comprised of Kaempferol-3-O-sophoroside-7-O-diglucoside, Kaempferol-3,7,4'-O-d-triglucoside, Kaempferol-3-O-feruloyl-sophoroside-7-O-d-glucoside, and Kaempferol-3-O-sinapoyl-sophoroside. Moreover, it presented higher scavenging ability against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and hydroxyl (OH) radical than crude extract. In conclusion, kale flavonoids can be well concentrated by NKA-9 resin and the purified flavonoids extract has good antioxidant activity which can be potentially applied in food, cosmetic or pharmacy industries.

Green and Efficient Extraction Approach for Polyphenol Recovery from Lotus Seedpods (Receptaculum Nelumbinis): Gas-Assisted Combined with Glycerol

In this paper, the gas-assisted combined with glycerol extraction (GAGE) for polyphenol recovery from lotus seedpods (LSPs) was modeled and optimized. Box-Behnken design was applied to optimize the total polyphenol content (TPC) of LSP along with enhancing antioxidant activities using response surface methodology based on the TPC extraction yield (%), which was affected by glycerol concentration, time, temperature, and glycerol-to-solid ratio. The optimal conditions for the LSP extract were glycerol-to-solid ratio, 42 mL/g; time, 50 min; concentration of glycerol, 45%; and temperature, 70 °C. Ultra-high-pressure liquid chromatography integrated with triple-time-of-flight mass spectrophotometry (UPLC-Triple-TOF/MS) analysis revealed nine biologically active polyphenols. Furthermore, Fourier-transform infrared spectroscopy and scanning electron microscopy results demonstrated the effect and influence during extraction. The findings suggested that GAGE is a potential, green, and high-efficiency alternative that could be used to recover polyphenols from plant source byproducts.

An ionic covalent organic framework for rapid extraction of polar organic acids from environmental waters

An ionic covalent organic framework (Fe₃O₄@EB-TFB-iCOF) as a polar adsorbent was synthesized and characterized. It was applied in the magnetic solid phase extraction (MSPE) of four polar organic acids, namely, 2-(2,4,5-trichlorophenoxy)propionic acid, 2-methyl-4-chlorophenoxy acetic acid, naphthyloxyacetic acid, and naphthylacetic acid. The organic acids were detected by high performance liquid chromatography-ultraviolet analysis (HPLC-UV). A method for the determination of organic acids based on MSPE-HPLC-UV was established. The method shows good linear regression (R²≥ 0.9950), high precision (1.53-3.80%, n = 6), and low detection limit (0.10-0.49 ng mL^-1). The recovery rate of environmental water samples ranges from 73.3% to 101.0%. This method provides a possibility for high sensitivity analysis of polar organic acids.

Adsorption and Desorption Characteristics of Total Flavonoids from Acanthopanax senticosus on Macroporous Adsorption Resins

We examined the application of six different resins with the aim of selecting a macroporous resin suitable for purifying Acanthopanax senticosus total flavonoids (ASTFs) from Acanthopanax senticosus crude extract (EAS) by comparing their adsorption/desorption capacities, which led to the selection of HPD-600. Research on the adsorption mechanism showed that the adsorption process had pseudo-second-order kinetics and fit the Freundlich adsorption model. Moreover, the analysis of thermodynamic parameters indicated that the adsorption process is spontaneous and endothermic. The optimal conditions for purification of ASTFs were determined as sample pH of 3, 60% ethanol concentration, and 3 BV·h⁻¹ flow rate, for both adsorption and desorption, using volumes of 2.5 and 4 BV, respectively. The application of macroporous resin HPD-600 to enrich ASTFs resulted in an increase in the purity of total flavonoids, from 28.79% to 50.57%. Additionally, the antioxidant capacity of ASTFs was higher than that of EAS, but both were lower than that of L-ascorbic acid. The changes in ASTFs compositions were determined using ultra-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS), with the results illustrating that the levels of seven major flavonoids of ASTFs were increased compared to that in the crude extract.

Optimization of Enzyme-Assisted Extraction and Purification of Flavonoids from Pinus koraiensis Nut-Coated Film and Antioxidant Activity Evaluation

Pinus koraiensis nut-coated film is a kind of by-product of nut processing, which has been shown to contain flavonoids, polyphenols, and other substances that can be used to produce natural antioxidant extracts. In this study, response surface methodology (RSM) was used to optimize the extraction process of flavonoids of P. koraiensis nut-coated film (PNF), and macroporous resin HPD600 was used to purify PNF (P-PNF). Its antioxidant activity was examined by DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging capacity, oxygen free radical absorption capacity (ORAC), total oxygen radical capture (TRAP), and iron ion reduction capacity. Under the ideal extraction conditions comprising a cellulase dosage of 90 U/g, a material/liquid ratio of 1:20 (g/mL), and an extraction time of 2 h, the PNF yield was 3.37%. Purification conditions were sample concentration of 2.0 mg/mL, pH of 5, water washing volume of 3 bed volume (BV), eluent ethanol concentration of 50%, and volume of 2 BV. The P-PNF recovery was 84.32%, and purity increased from 33.80% to 61.70%. Additionally, P-PNF showed increased antioxidant activity compared to PNF. Cumulatively, this study obtained the optimal values for the process parameters in order to achieve the maximum rates of extraction of PNF for economically optimal production at an industrial scale.

Adsorption and desorption characteristics of a phenolic compound from Ecklonia cava on macroporous resin

This study aimed to develop efficient adsorption and desorption processes to purify phenolic compounds from Ecklonia cava. We compared the adsorption and desorption properties of five resins. HP2MG showed the highest adsorption and desorption capacities and adsorption rate; hence, it was selected for phenolic compound purification. Adsorption isotherm parameters indicated favorable adsorption between HP2MG and phenolic compounds. Thermodynamic parameters showed that the absorption process physically proceeded. In the dynamic adsorption process, adsorption property was assessed based on bed length (4-10 cm) and flow rate (1.64-3.27 mL/min). The breakthrough point increased with increased bed length and decreased adsorption flow rate. However, the high desorption flow rate shortened the processing time. The phenolic contents, anti-glycation activity and antioxidant activity of the extract were measured before and after purification. The dieckol and phlorofucofuroeckol-A increased three times after purification. The purified extract showed higher anti-glycation and antioxidant activities than the extract.

Separation of epigallocatechin gallate and epicatechin gallate from tea polyphenols by macroporous resin and crystallization

Epigallocatechin gallate (EGCG) and epicatechin gallate (ECG) are the most abundant ester catechins of green tea polyphenols (GTPs) with numerous potential bioactivities, which have wide application prospects in the fields of medicine and functional foods. In this study, a new method using macroporous resin and crystallization was established to separate and purify EGCG and ECG. Two resins with high adsorption and desorption capacities for EGCG and ECG were screened through static adsorption/desorption tests, and the LX-20B resin was selected through column chromatography due to its best separation effect. Moreover, the column separation parameters of LX-20B resin (sample amount, ethanol elution concentration, elution volume, and elution flow rate) were optimized. After resin purification, the EGCG and ECG purity were 70.08 ± 2.55% and 74.97 ± 2.66%, respectively, and the recovery rates were 68.07 ± 2.43% and 74.28 ± 2.24%, respectively. After crystallization, the EGCG purity reached 95.87 ± 0.89%, with a total recovery rate of 58.66%, and the ECG purity reached 95.55 ± 1.30%, with a total recovery rate of 62.45%. The separation efficiency of the resin showed no significant change after 6 cycles. These results show the proposed method to be a simple, eco-friendly, and cost-effective separation method for the industrial separation and purification of EGCG and ECG from GTPs.

Ultrasound-assisted adsorption/desorption for the enrichment and purification of flavonoids from baobab (Adansonia digitata) fruit pulp

This work described the purification and enrichment of flavonoids from baobab (Adansonia digitata) fruit pulp (BFP) by ultrasound-assisted adsorption/desorption procedure using macroporous resins. Four resins were tested and HPD-500 polar resin exhibited the best adsorption/desorption properties. Based on preliminary experiments and literature reports, the effects of various ultrasonic conditions including high power short time (HPST, 540 W for 5 min), medium power medium time (MPMT, 270 W for 15 min) and low power long time (LPLT, 45 W for 30 min) as well as different temperatures (T = 25-45 °C) on the adsorption of Total Flavonoids Content (TFC) were investigated in comparison with orbital shaking/no sonication (NS). Also, the effect of ultrasound on the desorption capacity and recovery of TFC was determined at different concentrations of ethanol (30-100%). Remarkably, ultrasonic treatment significantly increased the adsorption/desorption capacity and recovery and shortened the equilibrium time. The pseudo-second-order kinetic and Freundlich isotherm models better delineated the adsorption process under ultrasound. Moreover, the adsorption process was both spontaneous and thermodynamically favourable with physical adsorption and multilinear intraparticle diffusion being the predominant mechanisms of the whole process. HPST treatment at 25 °C with 80% ethanol as the desorption solvent most noticeably enhanced the adsorption/desorption of flavonoids and contributed to the highest recovery of TFC, Total Phenolic Content (TPC), and antioxidant capacity in addition to a 5-8-fold reduction in total sugar and acid contents when compared with NS treatment. Moreover, HPLC analysis revealed that the content of nine out of thirteen phenolic compounds from the HPST treatment was the highest, and the individual flavonoids content increased by 2-3-fold compared with the other treatments. Our analyses suggested that ultrasound can be employed as a practical approach to intensify the adsorption and desorption of functional compounds in BFP.

A novel process for asparagus polyphenols utilization by ultrasound assisted adsorption and desorption using resins

The ultrasound assisted purification of asparagus polyphenols by adsorption and desorption on the macroporous resins was investigated. The ultrasound within the selected intensities (12-120 W) and temperatures (25-35 °C) increased the adsorption and desorption capacities of asparagus polyphenols on D101 resins. Higher ultrasound intensity (120 W) and lower temperature (25 °C) benefited the adsorption process and the adsorption capacity of total polyphenols after ultrasound was 3.95 mg/g, which was 2 times than that obtained after shaking at 120 rpm. Meanwhile, ultrasound can significantly shorten the equilibrium time and the adsorption process of asparagus polyphenols could be well described by Pseudo-second order model and Freundlich model. Stereoscopic microscope was first used to investigate the microstructure characterization of resins, indicating that ultrasound mainly enhanced the surface roughness of resins. Interestingly, rutin possessed the highest adsorption capacities and ferulic acid had the highest the desorption capacities among the studied individual polyphenols. The obtained results evidenced on a progressive insight of application of ultrasound assisted resins for purification of asparagus polyphenols.

The high-efficient production of phelligridin LA by Inonotus baumii with an integrated fermentation-separation process

The phelligridin LA was one of the valuable metabolites synthesized by the medicinal fungus Sanghuang in liquid fermentation. In the improvement of PLA productivity by fermentation, we investigated the optimal conditions for the efficient separation of PLA from the fermentation broth with a chromatographic column packed with the macroporous resin ADS-17. Based on the findings, we further developed an integrated bioreactor system that coupled the fermentation and separation of PLA. Fermentation experiments with the bioreactor system testified the performance of our design in fortification of the PLA production: an improvement of PLA production by 2.14 folds was successfully achieved due to the prompt removal of the PLA, while the formation of hyphae biomass was not affected. Also, the integrated system could afford a simultaneous purification of PLA to a purity of 92.95% with a recovery of 84.3%, which was comparable to that of the PLA purified with an additional process (97.53%), at a reasonable recovery. This study provided a feasible approach for the improved production of PLA by fermentation. Besides, the design of the integrated bioreactor system offered a useful reference for the fermentation process development of fungi for the production of diverse valuable metabolites.