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Staphylococcus aureus is one of the most frequently food-contaminated incidence of healthcare-associated Gram-positive bacteria. The antibacterial function and mechanism of phenolic compounds from dandelion are still unclear. Herein, this work aims to screen one of dandelion phenolic extracts with the strongest antibacterial function from its organ such as flower, stem, leaf and root, and to reveal its antibacterial mechanism. The results indicated dandelion flower phenolic extract (DFPE) containing the highest content of caffeic acid, followed by luteolin and luteolin-7-O-glucoside. They, especially caffeic acid and luteolin-7-O-glucoside, played a key role in making the bacterial cellular-membrane ruptured against the bacteria. The leakage of the intracellular substances (adenosine triphosphate and Na+-K+ ATPase) was further confirmed. Conventional hydrogen bond, pi-anion, pi-alkyl were involved in the interaction between caffeic acid or luteolin-7-O-glucoside and Na+-K+ ATPase. Additionally, the dynamic equilibrium of the liganded ATPase complex were achieved after 105 ns, and the lower values from the radius of gyration and solvent accessible surface area in the complex demonstrated the highly tight and compact structure of the liganded protein. The highest free binding energy (ΔGbind = -47.80 kJ/mol) between Na+-K+ ATPase and luteolin-7-O-glycloside was observed. Overall, DFPE can be used as an effective anti-bacterial agent due to the contribution of its bioactive ingredients such as caffeic acid and luteolin-7-O-glucoside for membrane-breaking.Communicated by Ramaswamy H. Sarma.
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Investigation of edible oil stability involves interactions between additive polyphenols and the inherent tocopherols. The work aimed to identify endogenous polyphenols to produce the synergistic effect with α-tocopherol in olive oil and to find the right action ratio. Caffeic acid and quercetin were selected from the 15 main endogenous phenolic compounds in olive oil. Quercetin had the strongest synergistic effect with α-tocopherol at 2:1 in the olive oil model. The rate of 2:1 also was the turning point of the change of synergism. Furthermore, the addition of quercetin and α-tocopherol at 2:1 to olive oil resulted in lower POV, K232, K270, and secondary oxidation products such as (E, E)-2,4-decadienal and 2-pentylfuran than the olive oil model with a single antioxidant in three months of accelerated oxidation. The dynamic changes of antioxidants during oxidation in olive oil indicated that their synergistic effect was the repair and regeneration of α-tocopherol by quercetin.
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Quercetina , alfa-Tocoferol , Aceite de Oliva , Aceites de Plantas , Antioxidantes , Fenoles/análisis , Polifenoles , Oxidación-ReducciónRESUMEN
Food-derived α-glucosidase inhibitory peptides have gained significant interest in treating type 2 diabetes mellitus (T2DM) owing to their favorable safety profiles. Molecular docking combined with molecular dynamics simulation was performed to screen α-glucosidase inhibitory peptides from Ginkgo biloba seed cake (GBSC), and two novel peptides (Met-Pro-Gly-Pro-Pro (MPGPP) and Phe-Ala-Pro-Ser-Trp (FAPSW)) were acquired. The results of molecular docking and molecular dynamics simulation suggested that FAPSW and MPGPP could generate stable complexes with 3wy1, and the electrostatic and van der Waals forces played contributory roles in FAPSW and MPGPP binding to 3wy1. The α-glucosidase inhibition assay corroborated that FAPSW and MPGPP had good α-glucosidase inhibition capacity, with IC50 values of 445.34 ± 49.48 and 1025.68 ± 140.78 µM, respectively. In vitro simulated digestion results demonstrated that FAPSW and MPGPP strongly resisted digestion. These findings lay a theoretical foundation for FAPSW and MPGPP in treating T2DM.
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Diabetes Mellitus Tipo 2 , Inhibidores de Glicósido Hidrolasas , Humanos , Simulación del Acoplamiento Molecular , Inhibidores de Glicósido Hidrolasas/química , alfa-Glucosidasas/química , Ginkgo biloba/metabolismo , Simulación de Dinámica Molecular , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Péptidos/química , Semillas/metabolismo , CinéticaRESUMEN
We tested a series of SQ109 analogues against Mycobacterium tuberculosis and M. smegmatis, in addition to determining their uncoupling activity. We then investigated potential protein targets, involved in quinone and cell wall biosynthesis, using "rescue" experiments. There was little effect of menaquinone on growth inhibition by SQ109, but there were large increases in the IC50 of SQ109 and its analogues (up to 20×) on addition of undecaprenyl phosphate (Up), a homologue of the mycobacterial decaprenyl (C50) diphosphate. Inhibition of an undecaprenyl diphosphate phosphatase, an ortholog of the mycobacterial phosphatase, correlated with cell growth inhibition, and we found that M. smegmatis cell growth inhibition could be well predicted by using uncoupler and Up-rescue results. We also investigated whether SQ109 was metabolized inside Mycobacterium tuberculosis, finding only a single metabolite, previously shown to be inactive. The results are of general interest since they help explain the mechanism of SQ109 in mycobacteria.
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Mycobacterium tuberculosis , Tuberculosis , Humanos , Antituberculosos/farmacología , Antituberculosos/metabolismo , Difosfatos/farmacología , Tuberculosis/tratamiento farmacológico , Tuberculosis/microbiología , Mycobacterium smegmatisRESUMEN
The aim of this study was to investigate the antiglycation activity and mechanism of two identified peptides, Valine-Valine-Phenylalanine-Proline-Glycine-Cysteine-Proline-Glutamic acid (VVFPGCPE) and Serine-Valine-Aspartic acid-Aspartic acid-Proline-Arginine-Threonine-Lysine (SVDDPRTL), from Ginkgo biloba seeds protein hydrolysates. Both VVFPGCPE and SVDDPRTL were efficient in bovine serum albumin (BSA)-methylglyoxal (MGO) model to inhibit BSA glycation, while VVFPGCPE showed higher antiglycation activity than SVDDPRTL. In antioxidant assays, VVFPGCPE scavenged more hydroxyl and super anion radicals, and chelated more Fe2+. Moreover, VVFPGCPE was more efficient in alleviating glycoxidation since it retained higher content of tryptophan and reduced dityrosine and kynurenine generation. Compared with SVDDPRTL, VVFPGCPE showed better performance in inhibiting protein aggregation and amyloid-like fibrillation formation. Therefore, VVFPGCPE was selected for further mechanism study. The circular dichroism analysis suggested VVFPGCPE could preserve α-helix structure and stabilize protein structure. The MGO trapping assay indicated VVFPGCPE (5 mg/mL) could capture 66.25% MGO within 24 h, and the mass spectrometry revealed VVFPGCPE could trap MGO by forming VVFPGCPE-mono-MGO adducts. Besides, molecular simulations suggested VVFPGCPE could interact with key glycation residues, arginine and lysine residues, of BSA mainly through van der Waals and hydrogen bonds. This study might supply a theoretical basis for the development of VVFPGCPE as an effective antiglycation agent.
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Ginkgo biloba , Reacción de Maillard , Péptidos , Arginina , Ácido Aspártico , Ginkgo biloba/química , Ginkgo biloba/metabolismo , Productos Finales de Glicación Avanzada/metabolismo , Lisina/farmacología , Lisina/química , Reacción de Maillard/efectos de los fármacos , Péptidos/farmacología , Prolina , Piruvaldehído/química , Albúmina Sérica Bovina/metabolismo , ValinaRESUMEN
In this study, Toxicodendron vernicifluum fisetin chelated silver nanoparticles (FT-AgNPs) with outstanding antioxidant and antimicrobial activities were constructed via self-assembly. To surprise, 0.6 wt% FT-AgNPs was compatibly dispersed into the 1:1 chitosan/pullulan (CS/PUL, CP) matrix. The hydrogen bonding and electrostatic interaction between FT-AgNPs and CP, slightly increased the CP thermal stability, and greatly enhanced the tensile strength to 61.2 MPa, water vapor permeability below 20 kg/m2â¢d. Furthermore, after treated with the composite hydrocolloid film (FT-AgNPs/CP), the reactive oxygen species level of the treated Aspergillus niger cells was significantly increased, and the membrane permeability was enhanced. It effectively slowed down the decay of litchi fruit induced by microbial infection under the storage at 25 °C (15 d of the 0.6 % FT-AgNPs/CP treatment vs 9 d of the control). In addition, 0.024 µg/kg Ag+ residual in lichi pulp verified the qualified safety of the application of the 0.6 % FT-AgNPs/CP.
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Quitosano , Litchi , Nanopartículas del Metal , Frutas , Plata/farmacología , Antibacterianos/farmacologíaRESUMEN
The inhibition of α-glucosidase activity has been recognized as an effective approach for treating type 2 diabetes mellitus (T2DM). In recent years, much emphasis has been placed on identifying peptides with α-glucosidase inhibitory activity and elucidating the mechanisms underlying their inhibitory effect in treating T2DM. This study aims to identify peptides with good α-glucosidase inhibitory activity from the hydrolysate of ginkgo biloba seed cake protein isolate (GCPI) using in silico screening. It was found that the hydrolysate from Alcalase exhibited the strongest inhibitory effect on α-glucosidase (IC50 12.94 ± 0.37 mg/mL). Three novel peptides with α-glucosidase inhibitory activity, i.e., Leu-Ser-Met-Ser-Phe-Pro-Pro-Phe (LSMSFPPF), Val-Pro-Lys-Ile-Pro-Pro-Pro (VPKIPPP) and Met-Pro-Gly-Pro-Pro-Ser-Asp (MPGPPSD), were further identified from the hydrolysate of Alcalase by in silico screening. LSMSFPPF exhibited the strongest inhibitory activity (IC50 454.33 ± 32.45 µM), followed by MPGPPSD (IC50 943.82 ± 73.10 µM) and VPKIPPP (IC50 1446.81 ± 66.98 µM). The pharmacophore model revealed that hydrogen bonds played a critical role in α-glucosidase inhibition.
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Diabetes Mellitus Tipo 2 , alfa-Glucosidasas , Secuencia de Aminoácidos , Tripsina , Ginkgo biloba , Proteínas , Péptidos/farmacología , Fragmentos de Péptidos , SubtilisinasRESUMEN
The aim of this study was to evaluate the effects of geographic location (i.e., latitude, longitude, altitude) and soil fertility (i.e., nitrogen, phosphorus) on main phenolic compounds and fatty acids in VOO nearby the Bailong River in Longnan city, a representative planting-region in China. The geographical distribution analysis showed that the sampling-points from the middle reaches of Bailong River had higher secondary metabolites, such as oleacein and oleocanthal. Correlation analysis revealed that the contents of ligustroside, vanillic acid and rutin were negatively correlated with altitude while the contents of heptadecenoic acid, oleic acid and eicosenoic were positively related to the altitude. Moreover, the excessive available nitrogen had an adverse effect on the content of phenolic compounds and fatty acids in virgin olive oil. It was helpful for the accumulation of phenolic compounds and fatty acids in virgin olive oil when the level of available nitrogen ranged from 51 to 100 mg/kg. These findings are helpful for the geographic-location selection and fertilization management of olive orchard.
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Ácidos Grasos , Olea , Ácidos Grasos/análisis , Nitrógeno/análisis , Aceite de Oliva/análisis , SueloRESUMEN
To valorise olive mill wastewater phenols (OPs) potentially applied in food preservation, a novel stable and regularly spherical OPs-AgNPs (Davg = 78 nm) were successfully assembled in aqueous solution under the optimized conditions (pH 8.0, 5 mM AgNO3, 35C and 30 min). The results of antimicrobial zone diameters indicated that 50 µg/mL of promising OPs-AgNPs presented excellent antimicrobial effects. Especially, the cell wall damages of E. coli ATCC 23,815 were caused when OPs-AgNPs concentration was exceeded its MIC (8.58 µg/mL). Also, a significant down-regulating of the Ca2+-ATPase activity in E. coli was revealed, and the intracellular Ca2+ concentrations were thus decreased from 12.5 to 1.35 µg/mL after a treatment for 3 h. The apoptosis level of E. coli was significantly increased more than the control (55.13% of OPs-AgNPs vs 9.90% of control). In sum, OPs exerts enhanced antimicrobial function via penetrating cell membrane and targeting Ca2+-ATPase after chelated with AgNPs.
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Phenolic and triterpenoid compounds of the olive tree are recognized as having a key role in health promotion, thanks to their multiple protective actions in humans. To expand the source of these bioactive compounds, the phenolic and triterpenoid profiles of leaf, branch, destoned fruit, destoned pomace, shell, seed, and extra virgin olive oil from the Frantoio, Leccino, and Moraiolo olive cultivars were simultaneously characterized by HPLC-DAD-MS. Overall, 43 molecules were quantitated and expressed on the obtained dry extracts. Oleuropein was mainly concentrated in branches (82.72 g/kg), fruits (55.79 g/kg), leaves (36.71 g/kg), and shells (1.26 g/kg), verbascoside (4.88 g/kg) in pomace, and nüzhenide 11-methyl oleoside (90.91 g/kg) in seeds. Among triterpenoids, which were absent in shells, the highest amount of oleanolic acid was found in olive leaves (11.88 g/kg). HCT-116 colorectal cells were chosen to assess the cytotoxicity of the dry extract, using the phytocomplex from Frantoio, which was the richest in phenols and triterpenoids. The IC50 was also determined for 13 pure molecules (phenols and terpenoids) detected in the extracts. The greatest inhibition on the cell's proliferation was induced by the branch dry extract (IC50 88.25 µg/mL) and by ursolic acid (IC50 24 µM). A dose-dependent relationship was observed for the tested extracts.
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Hydroxytyrosol oligomer from bioenzymatic catalysis indicates a pleiotropic wellness improving (e.g. antioxidation, anti-inflammatory and anti-carcinogenesis) than its monomer. However, the processing parameters and the insightful mechanism of hydroxytyrosol polymerization are still lacking. To explore in detail the process of hydroxytyrosol polymerization, the effects of different reaction factors (solvent type, pH value of reaction solution, reaction temperature and time) on the polymerization yield were investigated, and molecular docking was executed to reveal the relevant structural variations of these enzymes. The results showed hydroxytyrosol polymerization implemented by laccase performed the best at 50 °C for 20 min in the aqueous buffer solution of pH 5.0. The docking results demonstrated PRO4, TYR7, ASP8, PRO12, LEU121 and VAL14 in site 9 of laccase interacted with hydroxytyrosol in hydrogen bonding, pi-sigma, pi-alkyl and van der Waals' force. Moreover, the molecular dynamic results implied their interaction-energy variation reaching balance within 175 ps, which confirmed the enzymes' structural changes. Meanwhile, structural analysis in torsion and bond lengths showed that the C-O of phenolic bonds from hydroxytyrosol evidently rotated and its length of the relevant O-H became longer when binding to laccase compared with free hydroxytyrosol. All the findings are helpful to strengthen the understanding for the enzymatic polymerization of catechol-based structures and the resulting o-dihydroxy-grafting oligomers could be potentially used in the field of functional foods, cosmetics and pharmaceuticals, even or an innovative bioenzyme design such as biosensor for measuring phenols in industrial effluent or preparing the singular oligomer oriented is worth being explored in future.Communicated by Ramaswamy H. Sarma.
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Lacasa , Monofenol Monooxigenasa , Catálisis , Peroxidasa de Rábano Silvestre/metabolismo , Simulación del Acoplamiento Molecular , Monofenol Monooxigenasa/metabolismo , Estrés Oxidativo , Alcohol Feniletílico/análogos & derivados , PolimerizacionRESUMEN
Hydroxytyrosol oligomer prepared by bioenzyme shows stronger health-promoting properties than its monomer. However, the polymerization process carried out by laccase, tyrosinase or horseradish peroxidase is still lacking in term of product characterization, kinetics and thermodynamics. To achieve these aspects, ATR-FT-IR, NMR, the Michaelis-Menten equation and isothermal titration calorimetry were explored. The results showed that the identified polymers presented a CC bond and a degree of polymerization less than six. Laccase showed the greatest affinity to hydroxytyrosol via comparison of Km and Vm. All of these polymerization processes were spontaneous and exothermic behaviuors ranging from 30 to 50 °C, and were driven by hydrogen bonds, van der Waals interactions and hydrophobic interactions. Furthermore, circular dichroism spectroscopy was used to reveal the enzymatic structural changes during the catalysis, which showed that ß-sheet levels for laccase, α-helix levels for tyrosinase, and the α-helix and random coil levels for horseradish peroxidase were dramatically decreased.
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Catecol Oxidasa/metabolismo , Peroxidasa de Rábano Silvestre/metabolismo , Polimerizacion , Calorimetría/métodos , Catálisis , Enlace de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Cinética , Lacasa/metabolismo , Oxidación-Reducción , Alcohol Feniletílico/análogos & derivados , Espectroscopía Infrarroja por Transformada de Fourier , TermodinámicaRESUMEN
Starch has received research focus due to its low cost, excellent film-forming ability, bio-compatibility, extensive sources, renewability and biodegradability. However, native starch with relatively strong hydrophilicity greatly limits its application in industries. Therefore, in this paper, the recent research advances in chemical modifications of starch for hydrophobicity, e.g., esterification, etherification, crosslinking, grafting and condensing reaction etc., were discussed. The changes of hydrophobicity and other properties due to chemical modifications were described, as well. Different applications of modified starch with better hydrophobicity, i.e., packaging industries, Pickering emulsion and pharmaceutical, are presented, too. Finally, the future research and prospects on chemical modifications of starch for hydrophobicity and their applications are proposed.
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Almidón/química , Interacciones Hidrofóbicas e HidrofílicasRESUMEN
Chinese quince seed proteins were sequentially extracted based on the modified Osborne method. Investigations showed that albumin and glutelin were the major fractions. The physicochemical and functional properties of these two fractions were determined. The results showed that both albumin and glutelin posed appropriate essential amino acid composition and met the minimum recommendation (World Health Organization/Food and Agriculture Organization) for adult diet, except for methionine. The hydrophobicity of albumin and glutelin were 1063.56 and 1170.21, respectively. According to differential scanning calorimeter analysis, the denaturation temperature of albumin and glutelin was 101.44 °C and 108.36 °C respectively, and the glutelin fraction had a better thermal stability. The solubility and apparent viscosity of albumin and glutelin were presented to be greatly influenced by pH values. The water holding capacity and oil adsorption capacity of glutelin were 5.44 g/g and 8.15 g/g, higher than those of albumin which were 3.76 g/g and 3.71 g/g, respectively. Circular dichroism determination revealed albumin and glutelin were mainly composed by α-helix and random coil structures. Albumin and glutelin presented the potential as favorable nutrition and functional additive in food industries.
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Purification and structural characterization of a novel polysaccharide fraction from Chaenomeles speciosa seeds were investigated. After hot water extraction and ethanol precipitation, the crude polysaccharide was sequentially purified with Cellulose DEAE-52 and gel-filtration chromatography, and a highly purified polysaccharide fraction (F3) was obtained. The structure of F3 was characterized by high-performance gel permeation chromatography (HPGPC), high performance liquid chromatography (HPLC), ultraviolet-visible (UV), Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectrum, together with methylation, scanning electron microscopy (SEM), atomic force microscope (AFM), and Congo-red test analysis. The results indicated that F3 was a homogeneous polysaccharide fraction with a molecular weight of 8.65 × 106 Da, and it was composed of Rha, GlcA, Gal, and Ara in a molar ratio of 6.34:5.73:47.14:40.13. The backbone of F3 was consisted of â3,6)-Galp-(1â, and the side chains of F3 were composed of Araf-(1â, â4)-GlcpA-(1â, â4)-Galp-(1â and â3)-Rhap-(1â. The hypoglycemic assays demonstrated F3 had good α-amylase and α-glucosidase inhibition activities, and their IC50 values were 6.24 mg/mL and 4.59 mg/mL respectively. Thus, the polysaccharide from Chaenomeles speciose could be applied as a potential natural source in retarding postprandial hyperglycemia effects.
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Frutas/química , Inhibidores de Glicósido Hidrolasas , Polisacáridos , Rosaceae/química , alfa-Amilasas , alfa-Glucosidasas/química , Inhibidores de Glicósido Hidrolasas/química , Inhibidores de Glicósido Hidrolasas/aislamiento & purificación , Polisacáridos/química , Polisacáridos/aislamiento & purificación , alfa-Amilasas/antagonistas & inhibidores , alfa-Amilasas/químicaRESUMEN
To expound the copigmentation effects of phenolics on blackberry wine residue anthocyanins (BWRA), the color and stability of BWRA with storage, thermal, light and oxidation treatments were evaluated by chromaticity, kinetics and structural simulation analysis. Results indicated that phenolic acids showed preferable copigmetation on BWRA solutions with the enhanced color, thermostability at 50-70⯰C and light stability, whereas the degradation was accelerated at 90⯰C. Meanwhile, flavonoids promoted the oxidation stability of BWRA. Of all the phenolic acids, ferulic acid presented the best copigmentation effect, and among the flavonoids rutin was the most active. Structural simulation suggested rutin and ferulic acid had the largest volume, potential energy (164.8 and 32.8â¯kcal/mol), minimized energy (39.2 and 11.3â¯kal/mol) and van der Waals energy (81.6 and 28.1â¯kcal/mol), respectively, which were favorable to the stabilization of the flavylium ion. The hydrogen bonding, π-π stacking and solvent effects were together involved in the copigmentation mechanism.
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Antocianinas/química , Fenoles/química , Rubus , Vino , Color , Ácidos Cumáricos/química , Flavonoides/química , Hidroxibenzoatos/química , Cinética , Oxidación-ReducciónRESUMEN
Chinese quince seed protein isolate (CPI) was extracted using aqueous extraction and the isoelectric precipitation method, and its physicochemical and functional properties were investigated. Results showed that CPI contained all essential amino acids with exception of methionine which met the minimum recommendations for adults (World Health Organization/Food and Agriculture Organization). The electrophoresis analysis of sodium dodecyl sulphate polyacrylamide gel indicated that the molecular weights of protein fractions were approximately 15-60â¯kDa. Differential scanning calorimetry analysis was conducted, and the denaturation temperature of CPI was 103.4⯰C. The surface hydrophobicity of CPI was found to be 932.80. The experiments showed that CPI had high emulsifying capacity, foaming stability, water holding capacity and oil adsorption capacity. Moreover, CPI also had outstanding gel formation capacity since its least gelation concentration of CPI was only 8%. All these results implied that CPI could be a nutritional protein resource and functional ingredient in the food industry.
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Proteínas de Plantas/química , Rosaceae/química , Adsorción , Aminoácidos Esenciales/análisis , Rastreo Diferencial de Calorimetría , Precipitación Química , Electroforesis en Gel de Poliacrilamida , Emulsiones/química , Interacciones Hidrofóbicas e Hidrofílicas , Peso Molecular , Proteínas de Plantas/aislamiento & purificación , Desnaturalización Proteica , Reología , Semillas/química , Solubilidad , Temperatura , Agua/químicaRESUMEN
Three techniques of ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE) and solvent extraction (SE) were used for enhancing the hydroxytyrosol (HT), maslinic acid (MA) and oleanolic acid (OA) extraction from olive pomace, being evaluated and compared through process parameters, kinetics and thermodynamics, plus greenness assessment analysis. Results showed that UAE yielded the maximum compounds due to a strong cavitation effect and the strongest mass and heat transfer efficiency involving the kinetic constants (h, Ce and K) and thermodynamic parameters (â³H, â³S and â³G). Additionally, the optimal extraction conditions were acquired: ethanol concentration of 90%, extraction temperature of 50⯰C, extraction time of 5â¯min, liquid to solid ratio of 30â¯mL/g, ultrasound intensity of 135.6â¯W/cm2, and ultrasound frequency of 60â¯kHz. UAE was confirmed as an effective and greener technique with the lowest E factor, energy consumption and carbon emission during the extraction process of bioactive compounds from olive pomace.
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Fraccionamiento Químico/métodos , Olea/química , Ácido Oleanólico/aislamiento & purificación , Alcohol Feniletílico/análogos & derivados , Triterpenos/aislamiento & purificación , Tecnología Química Verde , Calor , Cinética , Microondas , Alcohol Feniletílico/aislamiento & purificación , Solventes/química , Termodinámica , Ondas UltrasónicasRESUMEN
In this work, the influences of a biosurfactant, mannosylerythritol lipids-A (MEL-A) toward ß-glucosidase activity and their molecular interactions were studied by using differential scanning calorimetry (DSC), circular dichroism spectroscopy (CD), isothermal titration calorimetry (ITC), and docking simulation. The enzyme inhibition kinetics data showed that MEL-A at a low concentration (< critical micelle concentration (CMC), 20.0 ± 5.0 µM) enhanced ß-glucosidase activity, whereas it inhibited the enzyme activity at higher concentrations more than 20.0 µM, followed by a decreased Vmax and Km of ß-glucosidase. The thermodynamics and structural data demonstrated that the midpoint temperature (Tm) and unfolding enthalpy (ΔH) of ß-glucosidase was shifted to high values (76.6 °C, 126.3 J/g) in the presence of MEL-A, and the secondary structure changes of ß-glucosidase, including the increased α-helix, ß-turn, or random coil contents, and a decreased ß-sheet content were caused by MEL-A at a CMC concentration. The further ITC and docking simulations suggested the bindings of MEL-A toward ß-glucosidase were driven by weak hydrophobic interactions happened between the amino acid residues of ß-glucosidase and the fatty acid residues of MEL-A, in addition to hydrogen bonds between amino acids and hydroxyl in glycosyl residues of this biosurfactant.
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Glucolípidos/química , Lípido A/química , Tensoactivos/química , beta-Glucosidasa/química , Interacciones Hidrofóbicas e Hidrofílicas , Cinética , Unión Proteica , Estructura Secundaria de Proteína , Temperatura , TermodinámicaRESUMEN
The polyprenols and their derivatives are highlighted in this study. These lipid linear polymers of isoprenoid residues are widespread in nature from bacteria to human cells. This review primarily presents the synthesis and biological activities of polyprenyl derivatives. Attention is focused on the synthesis and biological activity of dolichols, polyprenyl ester derivatives and polyprenyl amines. Other polyprenyl derivatives, such as oxides of polyprenols, aromatic polyprenols, polyprenyl bromide and polyprenyl sulphates, are mentioned. It is noted that polyprenyl phosphates and polyprenyl-linked glycosylation have better antibacterial, gene therapy and immunomodulating performance, whereas polyprenyl amines have better for antibacterial and antithrombotic activity. Dolichols, polyprenyl acetic esters, polyprenyl phosphates and polyprenyl-linked glycosylation have pharmacological anti-tumour effects. Finally, the postulated prospect of polyprenols and their derivatives are discussed. Further in vivo studies on the above derivatives are needed. The compatibility of polyprenols and their derivatives with other drugs should be studied, and new preparations of polyprenyl derivatives, such as hydrogel glue and release-controlled drugs, are suggested for future research and development.