Comparison of Alternative Protein Hydrogels for Delivering Myricetin: Interaction Mechanism and Stability Evaluation.

Food protein carriers from different sources might have distinct stabilizing and enhancing effects on the same small molecule. To elucidate the molecular mechanism, five different sourced proteins including soy protein isolates (SPIs), whey protein isolates (WPIs), edible dock protein (EDP), Tenebrio molitor protein (TMP), and yeast protein (YP) were used to prepare protein hydrogels for delivering myricetin (Myr). The results suggested that the loading capacity order of Myr in different protein hydrogels was EDP (11.5%) > WPI (9.3%) > TMP (8.9%) > YP (8.0%) > SPI (7.6%), which was consistent with the sequence of binding affinity between Myr and different proteins. Among five protein hydrogels, EDP had an optimum loading ability since it possessed the highest hydrophobic amino acid content (45.52%) and thus provided a broad hydrophobic cavity for loading Myr. In addition, these protein-Myr composite hydrogels displayed the core-shell structure, wherein hydrogen bonding and hydrophobic interaction were the primary binding forces between proteins and Myr. Moreover, the thermal stability, storage stability, and sustained-release properties of Myr were significantly enhanced via these protein delivery systems. These findings can provide scientific guidance for deeper utilization of food alternative protein sources.

Analysis of widely targeted metabolites of quinoa sprouts (Chenopodium quinoa Willd.) under saline-alkali stress provides new insights into nutritional value.

Quinoa sprouts are a green vegetable rich in bioactive chemicals, which have multiple health benefits. However, there is limited information on the overall metabolic profiles of quinoa sprouts and the metabolite changes caused by saline-alkali stress. Here, a UHPLC-MS/MS-based widely targeted metabolomics technique was performed to comprehensively evaluate the metabolic profiles of quinoa sprouts and characterize its metabolic response to saline-alkali stress. A total of 930 metabolites were identified of which 232 showed significant response to saline-alkali stress. The contents of lipids and amino acids were significantly increased, while the contents of flavonoids and phenolic acids were significantly reduced under saline-alkali stress. Moreover, the antioxidant activities of quinoa sprouts were significantly affected by saline-alkali stress. The enrichment analysis of the differentially accumulated metabolites revealed that flavonoid, amino acid and carbohydrate biosynthesis/metabolism pathways responded to saline-alkali stress. This study provided an important theoretical basis for evaluating the nutritional value of quinoa sprouts and the changes in metabolites in response to saline-alkali stress.

Quality and functional properties of bread containing the addition of probiotically fermented Cicer arietinum.

This study aimed to determine the impact of supplementation with probiotically fermented chickpea (Cicer arietinum L) seeds on the quality parameters and functional characteristics of wheat bread. The addition of chickpea seeds caused significant changes in the chemical composition of the control wheat bread. The legume-supplemented products exhibited higher values of a* and b* color parameters and higher hardness after 24 h of storage than the control. The application of fermented or unfermented chickpeas contributed to an increase in total polyphenol and flavonoid contents, iron chelating capacity, and antioxidant properties of the final product. The variant containing unfermented seeds had the highest riboflavin content (29.53 ± 1.11 µg/100 g d.w.), Trolox equivalent antioxidant capacity (227.02 ± 7.29 µmol·L-1 TX/100 g d.w.), and free radical scavenging activity (71.37 ± 1.30 % DPPH inhibition). The results of this preliminary research have practical importance in the production of innovative bakery products with potential properties of functional food.

Widely targeted metabolomics reveals differences in metabolites of Paeonia lactiflora cultivars.

INTRODUCTION: Paeonia lactiflora contains diverse active constituents and exhibits various pharmacological activities. However, only partial identification of biologically active substances from P. lactiflora has been achieved using low-throughput techniques. Here, the roots of P. lactiflora, namely, Fenyunu (CK), Dafugui (DFG), and Red Charm (HSML), were studied. The primary and secondary metabolites were investigated using ultrahigh-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESIMS/MS). METHODS: The chemical compounds and categories were detected using broadly targeted UPLC-MS/MS. Principal component analysis (PCA), orthogonal partial least-squares discriminant analysis (OPLS-DA), and hierarchical clustering analysis (HCA) were carried out for metabolites of different varieties of P. lactiflora. RESULTS: A total of 1237 compounds were detected and classified into 11 categories. HCA, PCA, and OPLS-DA of these metabolites indicated that each variety of P. lactiflora was clearly separated from the other groups. Differential accumulated metabolite analysis revealed that the three P. lactiflora varieties contained 116 differentially activated metabolites (DAMs) involved in flavonoid, flavone, and flavonol metabolism. KEGG pathway analysis revealed that, in 65 pathways, 336 differentially abundant metabolites (DMs) were enriched in the CK and DFG groups; moreover, the type and content of terpenoids were greater in the CK group than in the DFG group. The CK and HSML groups contained 457 DMs enriched in 61 pathways; the type and amount of flavonoids, terpenoids, and tannins were greater in the CK group than in the HSML group. The DFG and HSML groups contained 497 DMs enriched in 65 pathways; terpenoids and alkaloids were more abundant in the HSML variety than in the DFG variety. CONCLUSIONS: A total of 1237 compounds were detected, and the results revealed significant differences among the three P. lactiflora varieties. Among the three P. lactiflora varieties, phenolic acids and flavonoids composed the largest and most diverse category of metabolites, and their contents varied greatly. Therefore, CK is suitable for medicinal plant varieties, and DFG and HSML are suitable for ornamental plant varieties. Twelve proanthocyanidin metabolites likely determined the differences in color among the three varieties.

Identification and characterization of silver nanoparticles from Erythrina indica and its antioxidant and Uropathogenic antimicrobial properties.

The plant Erythrina indica comes under Fabaceae family, mainly used for used in traditional medicine as nervine sedative, antiepileptic, antiasthmatic, collyrium in opthalmia, antiseptic. Current study focused synthesize of silver nanoparticles (AgNPs) by E. indica leaf ethanol extract. The green-synthesized AgNPs underwent characterization using multiple analytical techniques, including UV-visible, FTIR, DLS, SEM, TEM, XRD, and EDX, and estimation of their antioxidant activity and antimicrobial activity. Phytochemical analysis identified alkaloids, tannins, saponins, flavonoids, and phenols as secondary metabolites. The Total Phenol Content (TPC) was determined to be 237.35 ± 2.02 mg GAE-1, indicating a substantial presence of phenolic compounds. The presence of AgNPs was verified through UV-Visible analysis at 420 nm, and FT-IR revealed characteristic phenolic functional groups. DLS analysis indicated a narrow size distribution (polydispersity index - PDI: 3.47%), with SEM revealing spherical AgNPs of approximately 20 nm. TEM showed homogeneous, highly polycrystalline AgNPs with lattice spacing at 0.297. XRD analysis demonstrated crystallinity and purity, with distinct reflection peaks corresponding to miller indices of JCPDS card no. 01 087 1473. In vitro, AgNPs exhibited robust antioxidant activity like; DPPH, ABTS, and H2O2, surpassing E. indica-assisted synthesis. ABTS assay indicated higher antioxidant activity (81.94 ± 0.05%) for AgNPs at 734 nm, while E. indica extraction showed 39.67 ± 0.07%. At 532 nm, both E. indica extraction (57.71 ± 0.11%) and AgNPs (37.41 ± 0.17%) exhibited H2O2 scavenging. Furthermore, AgNPs displayed significant antimicrobial properties, inhibiting Staphylococcus aureus (15.7 ± 0.12 mm) and Candida albicans (10.7 ± 0.17 mm) byfor the concentration of 80 µg/mL. Through the characterizations underscore of the potential of Erythrina indica-synthesized AgNPs, rich in polyphenolic compounds, for pharmacological, medical, biological applications and antipyretic properties.

Potential application of green extracts rich in phenolics for innovative functional foods: natural deep eutectic solvents as media for isolation of biocompounds from berries.

The health-promoting effects of berries have attracted attention due to the possible application of their extracts as functional ingredients in food products. Natural deep eutectic solvents (NADESs) are a new generation of environmentally friendly solvents for the extraction of natural products, and they are green alternatives to organic solvents, and they can improve the solubility, stability, and bioavailability of isolated biocompounds. In this study, an efficient eco-friendly method was used for the extraction of phenolic compounds from different berries: chokeberries, blueberries, and black goji berries with a range of eutectic solvents consisting of hydrogen bond acceptors (HBAs) such as choline chloride, L-proline, L-glycine, and L-lysine and hydrogen bond donors (HBDs) such as malic, citric, tartaric, lactic and succinic acids, glucose and glycerol. The obtained results indicated the ability of NADESs towards selective extraction of phenolics; the eutectic system choline chloride : malic acid showed selective extraction of anthocyanins, while choline chloride : glycerol and choline chloride : urea showed selectivity towards flavonoids and phenolic acids. The methodology for screening of the NADES extraction performance, which included chromatographic profiling via high-performance thin layer chromatography combined with chemometrics and spectrophotometric essays, allowed effective assessment of optimal eutectic solvents for isolation of different groups of phenolics. Great antioxidant and antimicrobial activities of extracts, along with the green nature of eutectic solvents, enable NADES berry extracts to be used as "green-labelled" functional foods or ingredients.

Evaluation of Environmental Factor Effects on the Polyphenol and Flavonoid Content in the Leaves of Chrysanthemum indicum L. and Its Habitat Suitability Prediction Mapping.

The leaves of Chrysanthemum indicum L. are known to have various bioactive compounds; however, industrial use is extremely limited. To overcome this situation by producing high-quality leaves with high bioactive content, this study examined the environmental factors affecting the phytochemical content and antioxidant activity using C. indicum leaves collected from 22 sites in Kochi Prefecture, Japan. Total phenolic and flavonoid content in the dry leaves ranged between 15.0 and 64.1 (mg gallic acid g-1) and 2.3 and 11.4 (mg quercetin g-1), while the antioxidant activity (EC50) of the 50% ethanol extracts ranged between 28.0 and 123.2 (µg mL-1) in 1,1-Diphenyl-2-picrylhydrazyl radical scavenging assay. Among the identified compounds, chlorogenic acid and 1,5-dicaffeoylquinic acid were the main constituents in C. indicum leaves. The antioxidant activity demonstrated a positive correlation with 1,5-dicaffeoylquinic acid (R2 = 0.62) and 3,5-dicaffeoylquinic acid (R2 = 0.77). The content of chlorogenic acid and dicaffeoylquinic acid isomers varied significantly according to the effects of exchangeable magnesium, cation exchange capacity, annual temperature, and precipitation, based on analysis of variance. The habitat suitability map using the geographical information system and the MaxEnt model predicted very high and high regions, comprising 3.2% and 10.1% of the total area, respectively. These findings could be used in future cultivation to produce high-quality leaves of C. indicum.

Effects of Rhizopus-arrhizus-31-Assisted Pretreatment on the Extraction and Bioactivity of Total Flavonoids from Hibiscus manihot L.

The Hibiscus manihot L. (HML) Medic, an edible hibiscus of the Malvaceae family, is abundant with flavonoids. The study investigated how Rhizopus-arrhizus-31-assisted pretreatment affects the extraction and bioactivity of flavonoids from HML. The fiber structure of the fermented flavonoid sample (RFF) appears looser, more porous, and more disordered than the unfermented flavonoid sample (RUF). RFF demonstrates milder conditions and yields higher extraction rates. According to the Box-Behnken response surface optimization experiment, the optimal conditions for RFF include a material-liquid ratio of 1:41 g/mL, a 2 h extraction time, a 57% ethanol concentration, and an extraction temperature of 800 °C, resulting in a 3.69% extraction yield, which is 39.25% higher than that of RUF. Additionally, RFF exhibits greater activity than RUF in the radical-scavenging system. The IC50 values for DPPH, OH, and ABTS radicals are 83.43 µg/mL and 82.62 µg/mL, 208.38 µg/mL and 175.99 µg/mL, and 108.59 µg/mL and 75.39 µg/mL for RUF and RFF, respectively. UPLC-QTOF-MS analysis of the active components in the HML flavonoid sample revealed significant differences in the chromatograms of RUF and RFF, indicating that biofermentation led to substantial changes in composition and content from HML.

Constituents of Chimaphila japonica and Their Diuretic Activity.

Three new phenols (1-3), one new cyclohexanol (4), two known phenols (5-6), and six known flavonoids (7-12) were isolated from the n-butanol of the 75% ethanol extract of all plants of Chimaphila japonica Miq. Among them, compound 5 was named and described in its entirety for the first time, and compounds 9 and 10 were reported in C. japonica for the first time. The structures of all compounds were confirmed using a comprehensive analysis of 1D and 2D NMR and HRESIMS data. Biological results show that compounds 4, 7, and 11 exhibited potent diuretic activity. The modes of interaction between the selected compounds and the target diuretic-related WNK1 kinase were investigated in a preliminary molecular docking study. These results provided insight into the chemodiversity and potential diuretic activities of metabolites in C. japonica.

Agave angustifolia Haw. Leaves as a Potential Source of Bioactive Compounds: Extraction Optimization and Extract Characterization.

The leaves of Agave angustifolia Haw. are the main agro-waste generated by the mezcal industry and are becoming an important source of bioactive compounds, such as phenolic compounds, that could be used in the food and pharmaceutical industries. Therefore, the extraction and identification of these phytochemicals would revalorize these leaf by-products. Herein, maceration and supercritical carbon dioxide (scCO2) extractions were optimized to maximize the phenolic and flavonoid contents and the antioxidant capacity of vegetal extracts of A. angustifolia Haw. In the maceration process, the optimal extraction condition was a water-ethanol mixture (63:37% v/v), which yielded a total phenolic and flavonoid content of 27.92 ± 0.90 mg EAG/g DL and 12.85 ± 0.53 µg QE/g DL, respectively, and an antioxidant capacity of 32.67 ± 0.91 (ABTS assay), 17.30 ± 0.36 (DPPH assay), and 13.92 ± 0.78 (FRAP assay) µM TE/g DL. Using supercritical extraction, the optimal conditions for polyphenol recovery were 60 °C, 320 bar, and 10% v/v. It was also observed that lower proportions of cosolvent decreased the polyphenol extraction more than pressure and temperature. In both optimized extracts, a total of 29 glycosylated flavonoid derivatives were identified using LC-ESI-QTof/MS. In addition, another eight novel compounds were identified in the supercritical extracts, showing the efficiency of the cosolvent for recovering new flavonoid derivatives.

Preparation of the Myricetin-Loaded PEGylated Niosomes and Evaluation of their in†vitro Anti-Cancer Potentials.

Several edible plants contain flavonoids, including myricetin (Myr), which perform a wide range of biological activities. Myr has antitumor properties against various tumor cells. In this study Myr-loaded PEGylated niosomes (Myr-PN) were prepared and their anti-cancer activities were evaluated in vitro. Myr-PNs were prepared as a tool for drug delivery to the tumor site. Myr-PN was characterized in terms of size, zeta potential, and functional groups using dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (SEM). The Myr-PN size was 241 nm with a polydispersity index (PDI) of 0.20, and zeta potential -32.7±6.6 mV. Apoptotic properties of Myr-PN against normal and cancer cell lines were determined by flow cytometry and real-time quantitative PCR. Cancer cells showed higher cytotoxicity when treated with Myr-PN compared with normal cells, indicating that the synthesized nanoparticles pose no adverse effects. Apoptosis was induced in cells treated with 250 µg/mL of Myr-PN, in which 45.2 % of cells were arrested in subG1, suggesting that Myr-PN can induce apoptosis. In vitro, the synthesized Myr-PN demonstrated potent anticancer properties. Furthermore, more research should be conducted in vitro and in vivo to study the more details of Myr-PN anti-cancer effects.

Morin loaded mesoporous molecular sieves as novel devices to the potential treatment of tumor pathologies.

Morin is an antioxidant and anticancer flavonoid, extracted from natural sources, that may exert beneficial effects for several pathologies. Despite this, the administration of morin represents a challenge due to its low aqueous solubility. Mesoporous silica materials have emerged as biocompatible tools for drug delivery, as their pore size can be modulated for maximum surface area to volume ratio. In this contribution, we evaluate the ability of iron-modified mesoporous materials, for morin loading and controlled delivery. The SBA-15 and MCM-41 sieves were synthesized and modified with iron (metal content 4.02 and 6.27 % wt, respectivily). Characterization by transmission electron microscopy, XRD and UV-Vis revealed adequate pore size and agglomerates of very small metallic nanospecies (nanoclusters), without larger iron oxide nanoparticles. FT-IR spectra confirmed the presence of silanol groups in the solid hosts, which can interact with different groups present in morin molecules. SBA-15 materials were more efficient in terms of morin loading capacity (LC) due to their larger pore diameter. LC was more than 35% for SBA-15 materials when adsorptions studies were carried out with 9 mg of drug. Antioxidant activity were assayed by using DPPH test. Free iron materials presented a significate improvement as antioxidants after morin incorporation, reaching a scavenging activity of almost a 90%. On the other hand, in iron modified mesoporous materials, the presence of morin did not affect the scavenging activity. The results could be related with the formation of a complex between the flavonoid and the iron. Finally, biosafety studies using normal epithelial cells revealed that neither the loaded nor the unloaded materials exerted toxicity, even at doses of 1 mg/ml. These findings expand knowledge about mesoporous materials as suitable carriers of flavonoids with the aim of improving therapies for a wide range of pathologies.

Cloning, Expression, and Functional Characterization of Two Highly Efficient Flavonoid-di-O-glycosyltransferases ZmUGT84A1 and ZmUGT84A2 from Maize (Zea mays L.).

The maize (Zea mays L.) glycosyltransferase family 1 comprises many uridine diphosphate glycosyltransferase (UGT) members. However, UGT activities and biochemical functions have seldom been revealed. In this study, the genes of two flavonoid di-O-glycosyltransferases ZmUGT84A1 and ZmUGT84A2 were cloned from maize plant and expressed in Escherichia coli. Phylogenetic analysis showed that the two enzymes were homologous to AtUGT84A1 and AtUGT84A3. The two recombinant enzymes showed a high conversion rate of luteolin to its glucosides, mainly 4',7-di-O-glucoside and minorly 3',7-di-O-glucoside in two-step glycosylation reactions in vitro. Moreover, the recombinant ZmUGT84A1 and ZmUGT84A2 had a broad substrate spectrum, converting eriodictyol, naringenin, apigenin, quercetin, and kaempferol to monoglucosides and diglucosides. The highly efficient ZmUGT84A1 and ZmUGT84A2 may be used as a tool for the effective synthesis of various flavonoid O-glycosides and as markers for crop breeding to increase O-glycosyl flavonoid content in food.

Xanthohumol-A Miracle Molecule with Biological Activities: A Review of Biodegradable Polymeric Carriers and Naturally Derived Compounds for Its Delivery.

Xanthohumol (Xn), a prenylated chalcone found in Hop (Humulus lupulus L.), has been shown to have potent anti-aging, diabetes, inflammation, microbial infection, and cancer properties. Unfortunately, this molecule has undesirable characteristics such as inadequate intake, low aqueous solubility, and a short half-life. To address these drawbacks, researchers have made numerous attempts to improve its absorption, solubility, and bioavailability. Polymeric drug delivery systems (PDDSs) have experienced significant development over the last two decades. Polymeric drug delivery is defined as a formulation or device that allows the introduction of a therapeutic substance into the body. Biodegradable and bioreducible polymers are the ideal choice for a variety of new DDSs. Xn formulations based on biodegradable polymers and naturally derived compounds could solve some of the major drawbacks of Xn-based drug delivery. In this regard, the primary concern of this study is on presenting innovative formulations for Xn delivery, such as nanoparticles (NPs), nanomicelles, nanoliposomes, solid lipid nanoparticles (SLNs), and others, as well as the received in vitro and in vivo data. Furthermore, this work describes the chemistry and broad biological activity of Xn, which is particularly useful in modern drug technology as well as the cosmetics industry. It is also important to point out that the safety of using Xn, and its biotransformation, pharmacokinetics, and clinical applications, have been thoroughly explained in this review.

Structural and Functional Characterization of a Gene Cluster Responsible for Deglycosylation of C-glucosyl Flavonoids and Xanthonoids by Deinococcus aerius.

Plant C-glycosylated aromatic polyketides are important for plant and animal health. These are specialized metabolites that perform functions both within the plant, and in interaction with soil or intestinal microbes. Despite the importance of these plant compounds, there is still limited knowledge of how they are metabolized. The Gram-positive aerobic soil bacterium Deinococcus aerius strain TR0125 and other Deinococcus species thrive in a wide range of harsh environments. In this work, we identified a C-glycoside deglycosylation gene cluster in the genome of D. aerius. The cluster includes three genes coding for a GMC-type oxidoreductase (DaCGO1) that oxidizes the glucosyl C3 position in aromatic C-glucosyl compounds, which in turn provides the substrate for the C-glycoside deglycosidase (DaCGD; composed of α+ß subunits) that cleaves the glucosyl-aglycone C-C bond. Our results from size-exclusion chromatography, single particle cryo-electron microscopy and X-ray crystallography show that DaCGD is an α2ß2 heterotetramer, which represents a novel oligomeric state among bacterial CGDs. Importantly, the high-resolution X-ray structure of DaCGD provides valuable insights into the activation of the catalytic hydroxide ion by Lys261. DaCGO1 is specific for the 6-C-glucosyl flavones isovitexin, isoorientin and the 2-C-glucosyl xanthonoid mangiferin, and the subsequent C-C-bond cleavage by DaCGD generated apigenin, luteolin and norathyriol, respectively. Of the substrates tested, isovitexin was the preferred substrate (DaCGO1, Km 0.047 mM, kcat 51 min-1; DaCGO1/DaCGD, Km 0.083 mM, kcat 0.42 min-1).

Metabolomic analysis reveals the effect of ultrasonic-microwave pretreatment on flavonoids in tribute Citrus powder.

In this study, the ultrasonic-microwave pretreatment was defined as a processing technology in the production of tribute citrus powder, and it could increase the flavonoid compounds in the processing fruit powder. A total of 183 upregulated metabolites and 280 downregulated metabolites were obtained by non-targeted metabolomics, and the differential metabolites was mainly involved in the pathways of flavonoid biosynthesis, flavone and flavonol biosynthesis. A total of 8 flavonoid differential metabolites were obtained including 5 upregulated metabolites (6"-O-acetylglycitin, scutellarin, isosakuranin, rutin, and robinin), and 3 downregulated metabolites (astragalin, luteolin, and (-)-catechin gallate) by flavonoids-targeted metabolomics. The 8 flavonoid differential metabolites participated in the flavonoid biosynthesis pathways, flavone and flavonol biosynthesis pathways, and isoflavonoid biosynthesis pathways. The results provide a reference for further understanding the relationship between food processing and food components, and also lay a basis for the development of food targeted-processing technologies.

In Vitro Comparative Analysis of the Effect and Structure-Based Influencing Factors of Flavonols on Lipid Accumulation.

Flavonols represented by quercetin have been widely reported to have biological activities of regulating lipid metabolism. However, the differences in flavonols with different structures in lipid-lowering activity and the influencing factors remain unclear. In this study, the stability, transmembrane uptake ratio, and lipid metabolism regulation activities of 12 flavonol compounds in the 3T3-L1 cell model were systematically compared. The results showed that kaempferide had the highest cellular uptake ratio and the most potent inhibitory effect on adipogenesis at a dosing concentration of 20 µM, followed by isorhamnetin and kaempferol. They inhibited TG accumulation by more than 65% and downregulated the expression of PPARγ and SREBP1c by more than 60%. The other four aglycones, including quercetin, did not exhibit significant activity due to the structural instability in the cell culture medium. Meanwhile, five quercetin glucosides were quite stable but showed a low uptake ratio that no obvious activity was observed. Correlation analysis also showed that for 11 compounds except galangin, the activity was positively correlated with the cellular uptake ratio (p < 0.05, r = 0.6349). These findings may provide a valuable idea and insight for exploring the structure-based activity of flavonoids at the cellular level.

Study transport of hesperidin based on the DPPC lipid model and the BSA transport model.

Hesperidin (HE), a significant flavonoid polyphenolic compound present in citrus plants, exhibits diverse pharmacological effects. Considering the crucial involvement of biological membranes and transporter proteins in the transportation and biological processes of HE, it becomes essential to comprehend the potential mechanisms through which HE interacts with membranes and transporter proteins. In order to simulate the process of active molecule transport, a cell membrane model consisting of 1,2-dipalmitoyl-n-glycero-3-phosphatidylcholine (DPPC) and a transporter protein model of bovine serum albumin (BSA) were employed for investigation. The present study aimed to investigate the mechanism of action of hesperidin (HE) in DPPC and BSA using fluorescence quenching, Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). The localization and interaction of HE within liposomes were also elucidated. Furthermore, the binding of BSA and HE was analyzed through UV/Vis absorption spectroscopy, fluorescence spectroscopy, infrared spectroscopy, and computational biology techniques. Computational biology analysis revealed that the binding between HE and BSA primarily occurred via hydrogen bonding and hydrophobic interactions. This study aimed to investigate the role and mechanism of HE in the DPPC cell membrane model and the BSA transporter protein model, thereby offering novel insights into the action of HE in DPPC and BSA.

Use of 3-Deoxy-D-arabino-heptulosonic acid 7-phosphate Synthase (DAHP Synthase) to Enhance the Heterologous Biosynthesis of Diosmetin and Chrysoeriol in an Engineered Strain of Streptomyces albidoflavus.

Flavonoids are a large family of polyphenolic compounds with important agro-industrial, nutraceutical, and pharmaceutical applications. Among the structural diversity found in the flavonoid family, methylated flavonoids show interesting characteristics such as greater stability and improved oral bioavailability. This work is focused on the reconstruction of the entire biosynthetic pathway of the methylated flavones diosmetin and chrysoeriol in Streptomyces albidoflavus. A total of eight different genes (TAL, 4CL, CHS, CHI, FNS1, F3'H/CPR, 3'-OMT, 4'-OMT) are necessary for the heterologous biosynthesis of these two flavonoids, and all of them have been integrated along the chromosome of the bacterial host. The biosynthesis of diosmetin and chrysoeriol has been achieved, reaching titers of 2.44 mg/L and 2.34 mg/L, respectively. Furthermore, an additional compound, putatively identified as luteolin 3',4'-dimethyl ether, was produced in both diosmetin and chrysoeriol-producing strains. With the purpose of increasing flavonoid titers, a 3-Deoxy-D-arabino-heptulosonic acid 7-phosphate synthase (DAHP synthase) from an antibiotic biosynthetic gene cluster (BGC) from Amycolatopsis balhimycina was heterologously expressed in S. albidoflavus, enhancing diosmetin and chrysoeriol production titers of 4.03 mg/L and 3.13 mg/L, which is an increase of 65% and 34%, respectively. To the best of our knowledge, this is the first report on the de novo biosynthesis of diosmetin and chrysoeriol in a heterologous host.

Strategy for the Enzymatic Acylation of the Apple Flavonoid Phloretin Based on Prior α-Glucosylation.

The acylation of flavonoids serves as a means to alter their physicochemical properties, enhance their stability, and improve their bioactivity. Compared with natural flavonoid glycosides, the acylation of nonglycosylated flavonoids presents greater challenges since they contain fewer reactive sites. In this work, we propose an efficient strategy to solve this problem based on a first α-glucosylation step catalyzed by a sucrose phosphorylase, followed by acylation using a lipase. The method was applied to phloretin, a bioactive dihydrochalcone mainly present in apples. Phloretin underwent initial glucosylation at the 4'-OH position, followed by subsequent (and quantitative) acylation with C8, C12, and C16 acyl chains employing an immobilized lipase from Thermomyces lanuginosus. Electrospray ionization-mass spectrometry (ESI-MS) and two-dimensional nuclear magnetic resonance spectroscopy (2D-NMR) confirmed that the acylation took place at 6-OH of glucose. The water solubility of C8 acyl glucoside closely resembled that of aglycone, but for C12 and C16 derivatives, it was approximately 3 times lower. Compared with phloretin, the radical scavenging capacity of the new derivatives slightly decreased with 2,2-diphenyl-1-picrylhydrazyl (DPPH) and was similar to 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+). Interestingly, C12 acyl-α-glucoside displayed an enhanced (3-fold) transdermal absorption (using pig skin biopsies) compared to phloretin and its α-glucoside.