Rutin Ester Research Articles

Thermochemistry of pyrolyzed rutin and its esters prepared from facile biocatalytic route

Pyrolysis of quercetin-3-O-rutinoside or rutin and its esters were investigated. Purified ester samples were prepared from lipase-catalyzed esterification of the parent flavonoid, i.e., rutin using acyl donors with different carbon chain length. X-ray diffraction revealed the presence of crystalline peaks in the rutin esters. The degradation activation energies (Ea) as a function of conversion degree ? were determined using Kissinger?Akahira?Sunose and Flynn?Wall?Ozawa methods, with corroborative results. Disparity in Ea implies distinct thermal degradation routes. For all studied compounds, degradation is a non-spontaneous process. The presence of acyl moieties and their corresponding carbon chain length in relation to thermodegradation profiles, Ea, entropy (?S) and enthalpy (?H) changes of the pyrolysis are discussed.

Improved antioxidant activity of rutin via lipase-mediated esterification with oleic acid.

Oxidation is a major problem for oils and fats, which can be mitigated by antioxidants. Rutin has excellent antioxidant activity, but its poor lipid solubility greatly limits its practical application. In this study, an efficient enzymatic synthesis route of lipophilic rutin ester was established using oleic acid as an acyl donor, and the antioxidant potential of rutin oleate was evaluated for the first time by proton (1 H) nuclear magnetic resonance (NMR) spectroscopy. The synthesized product was finally identified as rutin oleate by Fourier transform infrared, high-performance liquid chromatography-mass spectrometry, and 1 H, carbon-13, and DEPT-135 NMR analyses, and the acylation site was the 4‴-OH of the rhamnose group in the rutin molecule. The maximum conversion was over 93% after 48 h of reaction using Novozym 435 as catalyst under the best conditions among these tests. The conversion of rutin ester decreased with the increase of carbon chain length and the number of carbon-carbon double bonds of the fatty acid molecule. Most importantly, rutin oleate exhibited antioxidant capacity comparable to butylated hydroxytoluene and its counterparts (rutin and oleic acid) at low temperatures (60°C), but had a significant advantage at high temperatures (120°C). The antioxidant activity of rutin was significantly enhanced by lipase-mediated esterification with oleic acid. Therefore, rutin oleate could be further developed as a novel antioxidant for use in oil- and fat-based foods. © 2023 Society of Chemical Industry.

Chemo- and regio-selective enzymatic lipophilisation of rutin, and physicochemical and antioxidant properties of rutin ester derivatives.

Enzymes are one of the most powerful tools in organic Green Chemistry and enzymatic reactions offer numerous advantages like regio- and enantio-selectivity along with their eco-friendly and sustainable nature. More specifically, lipases can catalyse both ester hydrolysis and formation depending on the nature of the substrate and water content. Herein, the focus is on the development of an enzymatically catalysed lipophilisation of natural compounds using lipases of microbial origin and the investigation of the optimal reaction conditions, aiming ultimately to ameliorate the compounds' properties. The flavonoid disaccharide rutin (quercetin-3-O-rutinoside) was the model compound on which the acylation protocol was built, allowing an efficient procedure to be established, while simultaneously offering the possibility of developing rapid, clear and robust methodologies, using state-of-the-art techniques, for analysis and purification of the synthesized compounds. An optimal 72 h reaction at 55 °C, using Candida antarctica lipase B immobilized on acrylic resin, combined with silicon dioxide as dehydrating agent, followed by product purification, achieved conversion ratios up to 50%. Full characterization and evaluation of the physicochemical and antioxidant properties of the esterified compounds was obtained. The lipophilicity of the rutin esters produced increased with increasing alkyl chain length, yet antioxidant properties were unaffected in comparison with the parent compound. A preparatively useful acylation protocol was established, allowing full investigation into the properties of the acylated compounds. It is also applicable for use on mixtures of compounds as most natural products are found in nature in mixtures and such a development greatly enhances the potential of this method for future commercial applications.

Probing the synergistic effects of rutin and rutin ester on the oxidative stability of sardine oil.

Multicomponent antioxidant mixture is proved to be highly effective in imparting oxidative stability to the edible oil. It is believed that the high efficacy of those mixtures is due to the synergistic effect exhibited by two or more components. The current study aims to analyse the synergistic effect of a flavonoid and its corresponding ester in improving the oxidative stability of n-3 PUFA rich sardine oil. The oxidative stability of rutin, esterified rutin and their combinations at three different concentrations was studied in sardine oil stored at 37ºC for 12days in contact with air under darkness. The combination of rutin and rutin ester showed maximum reduction of 54.2% in oxidation at 100mg/kg and 150mg/kg. Perhaps this is the first report on the synergistic effect of a flavonoid and its lipophilized ester for improving the oxidative stability of n-3 PUFA rich oil.

Synthesis of Rutin Derivatives to Enhance Lipid Solubility and Development of Topical Formulation with a Validated Analytical Method.

Rutin is available on the market as a topical formulation for the treatment of several conditions, such as internal bleeding, hemorrhoids, and varicose veins. However, these gels have low solubility and limited bioavailability due to their decreased lipid solubility. In this study, we aimed to synthesize potentially novel lipophilic rutin prodrugs. The suggested library of these rutin prodrugs includes changing the solubility profile to facilitate rutin transport across biological barriers, thereby improving drug delivery through topical application. Six rutin derivatives were synthesized based on the ester prodrug strategy. The synthesized compounds were formulated as topical ointments, and their permeability via Franz diffusion was measured. An ultraviolet (UV) analytical method was developed in our laboratories to quantify rutin derivatives both as raw materials and in final dosage forms. The analytical method was then validated. The results of Franz diffusion analyses showed that transdermal permeability increased by 10-fold for decaacetylated rutin compared to the other esterified rutins. A simple analytical method for the analysis of the formulated rutin ester was developed and validated. Moreover, the formulated ointment of decaacetylated rutin in our research laboratory was found to be stable under stability accelerated conditions. Synthesis of potentially more lipophilic compounds would yield novel rutin prodrugs suitable for topical formulation. This project provides a synthetic approach for many similar natural products. The research idea and strategy followed in this research project could be adapted by pharmaceutical and herbal establishments.

HSCCC Separations of Rutin Esters Obtained by Enzymatic Reaction Catalyzed by Lipase

The flavonoid rutin presents several pharmacological effects, despite this, its application in the pharmaceutical industry can be significantly limited by its low bioavailability. The development of lipophilic derivatives by esterification of hydroxyl groups with fatty acid chains may be an effective strategy to change their physicochemical properties. This work aims to use high-speed countercurrent chromatography (HSCCC) to isolate rutin esters produced by esterification reactions catalyzed by the immobilized lipase from Candida antarctica (Novozyme 435®). The lipase-catalyzed synthesis of rutin esters (R3-R18:2) in 2-methyl-2-butanol exhibited conversions that ranged from 16 to 40% and highest conversion for short chain fatty acids (R4-R12). After initial partitioning tests of the reaction mixture in different solvent proportions followed by thin layer chromatography (TLC) analysis, the biphasic solvent systems consisting in HEMWat (hexane/ethyl acetate/methanol/water) in different proportions were chosen to separate rutin esters. These esters were separated for the first time to the reaction mixture via HSCCC. This technique proved to be more advantageous than the traditionally one since it allowed quick isolation and high purity (≥ 90%) of the products. It also permitted a substrate recovery for reuse in other enzymatic reactions. Furthermore, the results add valuable information, specially concerning the structures elucidation of different rutin esters not previously described.

Development and in vitro characterization of an oral self-emulsifying delivery system (SEDDS) for rutin fatty ester with high mucus permeating properties

The aim of this study was to develop and evaluate a self-emulsifying delivery system (SEDDS) for oral rutin fatty ester administration and to improve its mucus permeating properties by the incorporation of the silicon polymer poly [dimethylsiloxane-co-(3-(2-(2-hydroxyethoxy)ethoxy)propyl]methylsiloxane] (PDMSHEPMS) in the formulation. In order to increase the lipophilicity of the flavonoid and to dissolve it in SEDDS, enzymatic acylation of rutin with lauric acid was catalyzed by lipase from Candida antarctica in acetone. Different formulations were evaluated regarding their emulsifying properties and ability to dissolve the rutin ester. Suitable SEDDS was chosen and characterized regarding droplet size, polydispersity index, and zeta potential. The rutin fatty ester was loaded into SEDDS to 7% (w/w). Different concentrations of PDMSHEPMS were incorporated in SEDDS for following mucus permeation studies. Formulation with 10% of PDMSHEPMS showed 1.9-fold increase in mucus permeation compared to the formulation without PDMSHEPMS. Furthermore, the formulation with 10% of PDMSHEPMS showed a significant increase in mucus permeation compared with rutin fatty ester without formulation. According to these results, SEDDS containing PDMSHEPMS might be a promising strategy to increase the oral bioavailability of rutin.

Kinetic study on the inhibition of xanthine oxidase by acylated derivatives of flavonoids synthesised enzymatically

Studies have reported that flavonoids inhibit xanthine oxidase (XO) activity; however, poor solubility and stability in lipophilic media limit their bioavailability and applications. This study evaluated the kinetic parameters of XO inhibition and partition coefficients of flavonoid esters biosynthesised from hesperidin, naringin, and rutin via enzymatic acylation with hexanoic, octanoic, decanoic, lauric, and oleic acids catalysed by Candida antarctica lipase B (CALB). Quantitative determination by ultra-high performance liquid chromatography–mass spectrometry (UHPLC–MS) showed higher conversion yields (%) for naringin and rutin esters using acyl donors with 8C and 10C. Rutin decanoate had higher partition coefficients (0.95), and naringin octanoate and naringin decanoate showed greater inhibitory effects on XO (IC50 of 110.35 and 117.51 μM, respectively). Kinetic analysis showed significant differences (p < .05) between the flavonoids before and after acylation regarding Km values, whereas the values for Vmax were the same, implying the competitive nature of XO inhibition.

Antioxidant efficacies of rutin and rutin esters in bulk oil and oil‐in‐water emulsion

The use of flavonoids as antioxidants in food formulations is limited due to their solubility and thereby their localization in the food products. However, enzymatic alkylation of flavonoids with lipophilic moieties alters their lipophilicity and thereby partitioning within different phases in a food product. This study aimed to evaluate the antioxidative efficiency of two derivatives of rutin, namely rutin laurate (C12:0) and rutin palmitate (C16:0) compared with their parent compound rutin and with butylated hydroxytoluene (BHT). Their efficiency as antioxidants at two different concentrations (25 and 200 × 10−6 m) was assessed in bulk oil and in an o/w emulsion system without and with iron addition. All evaluated compounds revealed antioxidant effects. However, rutin and BHT were the most efficient antioxidants in bulk oil followed by rutin palmitate, whereas rutin laurate acted as either an antioxidant or a prooxidant at low and high concentrations (25 and 200 × 10−6 m), respectively. In emulsions, rutin and BHT in high concentration (200 × 10−6 m) were more efficient than rutin esters. Thus, alcylation of rutin with medium chain fatty acids did not improve the antioxidant ability, neither in bulk oil nor in o/w emulsion. Interestingly, rutin had stronger antioxidative effect than BHT upon iron addition to the emulsion.Practical application: According to the antioxidant hypothesis, the polar paradox, more amphiphilic antioxidants should perform as better antioxidants in emulsions than more polar antioxidants. The finding in this study revealed that lipophilization of rutin did not improve its antioxidant capacity in emulsions compared to untreated rutin. This stresses the importance of evaluating the antioxidant in each emulsion systems before selecting appropriate antioxidants for optimal protection against lipid oxidation.Lipid oxidation in bulk oil and o/w emulsion. Rutin and BHT more efficient antioxidants in bulk oil and emulsion than rutin ester. Acylation of rutin with C12 or C16 did not improve the antioxidant ability of rutin neither in bulk oil or emulsion.

Inhibition of the sarco/endoplasmic reticulum Ca2+-ATPase (SERCA1) by rutin derivatives.

The effect of lipophilic rutin derivatives (acylated with fatty acid chain length of 16-22) on sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA1 isoform) compared to the parent molecule rutin was evaluated. Rutin derivatives caused concentration dependent decrease of SERCA1 activity (IC50 ~ 23-64 µM) and significant conformational alterations in the transmembrane region of the enzyme. Upon treatment by peroxynitrite, rutin derivatives exerted a hormetic effect, i.e. prevented enzyme activity decrease at low concentrations, while additionally inhibited at high concentrations. Concerning the posttranslational modifications of SERCA1, rutin esters: (i) induced a significant loss of free sulfhydryl groups, (ii) protected the enzyme from protein carbonyl formation, and (iii) prevented SERCA from tyrosine nitration (except R20:4 and R22:1). In silico study revealed a strong affinity of the derivative R20:4 to the transmembrane region of SERCA1, stabilized via hydrogen bonds with Glu90, Glu771, Thr778 and Thr848 residues. Interaction of rutin derivatives with Glu771, a residue involved in Ca(2+) binding, is likely to be responsible for the inhibitory effect of the esters.

The antioxidative effect of lipophilized rutin and dihydrocaffeic acid in fish oil enriched milk

AbstractThe antioxidative effect of phenolipids was evaluated in fish oil enriched milk emulsions as a model for a complex food system. Two different phenolipids modified from dihydrocaffeic acid (with C8 or C18:1) and rutin (with C12 or C16) were evaluated. Both dihydrocaffeate esters and rutin laurate showed significantly better antioxidant properties in milk emulsion compared with the original phenolics. However, rutin palmitate only performed slightly better as antioxidant than rutin. The results with rutin indicated that a cut‐off effect exists in relation to the alkyl chain length with respect to optimal antioxidant activity in milk emulsions. Thus, the optimal alkyl chain length is at least below 16 carbon atoms, and maybe even less for rutin esters. For dihydrocaffeate esters it was not possible to conclude on a cut‐off effect in relation to alkyl chain length and antioxidative effect due to the almost similar antioxidant effect of the two phenolipids. However, there was a tendency towards octyl dihydrocaffeate being slightly more efficient than oleyl dihydrocaffeate.Practical application: The finding that phenolipids are better antioxidants in milk emulsions than the original phenolic acid provides new knowledge that can be used to develop new antioxidant strategies to protect foods against lipid oxidation. However, the results indicate that both optimization of alkyl chain length for each type of phenolic, and optimization for each type of emulsion will be necessary in order to get the best oxidative stability of an emulsion with these phenolipids. Use of efficient antioxidants may lower the amount of antioxidant needed to protect against lipid oxidation and may in addition decrease the costs.

Polyphenol fatty acid esters as serine protease inhibitors: a quantum-chemical QSAR analysis

We investigated the ability of polyphenol fatty acid esters to inhibit the activity of serine proteases trypsin, thrombin, elastase and urokinase. Potent protease inhibition in micromolar range was displayed by rutin and rutin derivatives esterified with medium and long chain, mono- and polyunsaturated fatty acids (1e–m), followed by phloridzin and esculin esters with medium and long fatty acid chain length (2a–d, 3a–d), while unmodified compounds showed only little or no effect. QSAR study of the compounds tested provided the most significant parameters for individual inhibition activities, i.e. number of hydrogen bond donors for urokinase, molecular volume for thrombin, and solvation energy for elastase. According to the statistical analysis, the action of elastase inhibitors is opposed to those of urokinase and thrombin. Cluster analysis showed two groups of compounds: original polyphenols together with rutin esters with short fatty acid chain length and rutin esters with long fatty acid chain length.

Enzymatic Synthesis of Lipophilic Rutin and Vanillyl Esters from Fish Byproducts

Lipase-catalyzed synthesis of lipophilic phenolic antioxidants was carried out with a concentrate of n-3 polyunsaturated fatty acids (PUFAs), recovered from oil extracted from salmon ( Salmon salar ) byproduct. Vanillyl alcohol and rutin were selected for the esterification reaction, and obtained esters yields were 60 and 30%, respectively. The antioxidant activities of the esters were compared with those of commercial butylated hydroxytoluene (BHT) and α-tocopherol using DPPH radical scavenging and thiobarbituric acid assays. In the DPPH assay, rutin esters showed better activity than vanillyl esters, and on the contrary in lipophilic medium, vanillyl esters were found to be superior to rutin esters. In bulk oil system, the antioxidant activities of rutin and vanillyl derivatives were lower than that of BHT and α-tocopherol, but in emulsion, they showed better activity than α-tocopherol. By attaching to natural phenolics, the PUFAs are protected against oxidation, and PUFA improves the hydrophobicity of the phenolic, which could enhance its function in lipid systems.

Antioxidant properties of modified rutin esters by DPPH, reducing power, iron chelation and human low density lipoprotein assays

Practical limitations exist regarding the effectiveness of flavonoids as antioxidants in many food systems, possibly due to their poor solubility and miscibility in lipidic environments. Current strategies to improve these properties include enzymatically acylating flavonoids with lipophilic moieties. Herein, two derivatives of rutin (possessing C12:0 or C16:0 acyl groups) were assessed for their antioxidant properties, and compared with their parent compound, rutin and with butylated hydroxytoluene (BHT). While all compounds exhibited relatively strong radical scavenging abilities, modified rutin compounds exhibited decreased reducing power and metal chelating abilities as compared to rutin. Conversely, investigations on the oxidation of human low density lipoprotein (LDL) revealed that rutin laurate was most effective in inhibiting oxidation by prolonging LDL lag time for an in vitro system. With regards to in vivo considerations, a pre-treatment step confirmed that the ester bond linking rutin and acyl moieties was most susceptible to hydrolysis by digestive enzymes, while rutin itself was not degraded. Thus, acylation of rutin with medium or long chain fatty acids may result in improved antioxidant abilities in more complex systems, including LDL-oxidation assays. Likely reasons may include improved lipophilic solubility and partitioning properties allowing for better accessibility to the actual site of oxidation.

Lipophilic rutin derivatives for antioxidant protection of oil-based foods

The lipase-catalysed synthesis of lipophilic flavonoid antioxidants via rutin acylation with fatty acids (C4–C18) in 2-methylbutan-2-ol was investigated. Conversion yields of rutin fatty acid esters varied from 27% to 62%, depending on fatty acid chain length. Radical-scavenging capacity of compounds synthesized was evaluated against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, inhibition of lipid peroxidation was examined in β-carotene linoleate system and their potential to act as food antioxidants was studied in sunflower oil using Rancimat test. The results suggest that lipophilic rutin esters, prepared via enzymatic esterification of rutin and fatty acids, may be useful agents in protection of oil-based foods against oxidation. Induction times of esters in the Rancimat test increased with their hydrophobicity. Esters of rutin with stearate, palmitate, oleate, linoleate and linolenate were found to be the most efficient agents of all compounds tested.

Controllable Regioselective Acylation of Rutin Catalyzed by Enzymes in Non-aqueous Solvents

An efficient route to synthesize 3''- and 4'''-vinyl rutin esters has been developed by enzyme-catalyzed regioselective acylation of rutin with divinyl dicarboxylates in organic media. Alkaline protease from Bacillus subtilis provided 3''-O-substituted vinyl rutin esters in pyridine, and Novozym 435 gave 4'''-O-substituted vinyl rutin esters in tert-butanol.

Enzymatic synthesis of butyryl-rutin ester in organic solvents and its cytogenetic effects in mammalian cells in culture.

Enzymic acylation of a flavonoid, rutin, with trichloroethylbutyrate (TCEB) has been performed by subtilisin protease in anhydrous pyridine solution. The addition of a hydrophobic compound on rutin is expected to change the hydrophilic/hydrophobic balance of the molecule, giving new properties to this compound. This work aimed at investigating the various cytological properties of the rutin-ester and compared them with those of the native molecule. No difference in the levels of sister chromosomes exchange (SCE) between rutin and rutin-ester treated cells at doses varying from 25 to 200 micrograms/mL was found. On the contrary impressive difference in the induced frequency of micronuclei (MN) between rutin and rutin ester treated cells was observed, for example, at a dose of 100 micrograms/mL of rutin were 3.5% MN counted, whereas for a similar dose treatment with rutin-ester a frequency of 8% of MN was found. The fact that rutin-ester is causing significantly higher levels of MN than the rutin alone can be considered as a manifestation of a higher action of the agent on the chromosome owing to its easier penetration in to the cell after its esterification.