Enzymatic Hydrolysis of Rutin: Evaluation of Kinetic Parameters and Anti-Proliferative, Mutagenic and Anti-Mutagenic Effects.

The bioavailability of glucoside flavonoids is influenced by the nature of the sugar, glucosides being absorbed faster than rhamnoglucosides, for example. One strategy to enhance the bioavailability is enzymatic hydrolysis. In this study, some kinetic parameters of hesperidinase-mediated hydrolysis of rutin were evaluated using an UHPLC/QTOF-MSE analysis of the products of a bioconversion reaction. The resulting hydrolyzed rutins (after 4, 8 and 12 h of reaction) were submitted to anti-proliferative and Cytokinesis-Block Micronucleus (CBMN) assays in CHO-K1 cells. In the hesperidinase-mediated hydrolysis, the final concentration of quercetin-3-O-glucoside (Q3G) was directly proportional to the rutin concentration and inversely proportional to the reaction time. At an anti-proliferative concentration (2.5 µg/mL), hydrolyzed rutin derivatives did not show a mutagenic effect, except for the sample with a higher content of Q3G (after 4 h of the enzymatic hydrolysis of rutin). Moreover, the higher Q3G content in hydrolyzed rutin protected the CHO-K1 cells 92% of the time against methyl methanesulfonate-induced mutagenic damage. These results suggested that the anti-mutagenic effect of hydrolyzed rutin might be related to antioxidant and cell death induction. Presenting a good lipophilicity/hydrophilicity ratio, together with antioxidant and anti-mutagenic activities, the hesperidinase-mediated hydrolyzed rutin seemed to be a promisor raw material for the development of food supplements.

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.

Review of anticancer mechanisms of isoquercitin.

This review was based on a literature search of PubMed and Scielo databases using the keywords "quercetin, rutin, isoquercitrin, isoquercitin (IQ), quercetin-3-glucoside, bioavailability, flavonols and favonoids, and cancer" and combinations of all the words. We collected relevant scientific publications from 1990 to 2015 about the absorption, bioavailability, chemoprevention activity, and treatment effects as well as the underlying anticancer mechanisms of isoquercitin. Flavonoids are a group of polyphenolic compounds widely distributed throughout the plant kingdom. The subclass of flavonols receives special attention owing to their health benefits. The main components of this class are quercetin, rutin, and IQ, which is a flavonoid and although mostly found as a glycoside, is an aglycone (lacks a glycoside side chain). This compound presents similar therapeutic profiles to quercetin but with superior bioavailability, resulting in increased efficacy compared to the aglycone form. IQ has therapeutic applications owing to its wide range of pharmacological effects including antioxidant, antiproliferative, anti-inflammatory, anti-hypertensive, and anti-diabetic. The protective effects of IQ in cancer may be due to actions on lipid peroxidation. In addition, the antitumor effect of IQ and its underlying mechanism are related to interactions with Wnt signaling pathway, mixed-lineage protein kinase 3, mitogen-activated protein kinase, apoptotic pathways, as well proinflammatory protein signaling. This review contributed to clarifying the mechanisms of absorption, metabolism, and actions of IQ and isoquercitrin in cancer.

Characterization of the antioxidant activity of aglycone and glycosylated derivatives of hesperetin: an in vitro and in vivo study.

The flavonoids are mainly present in Citrus fruits as their glycosyl derivatives. This study was conducted comparing in vitro xanthine oxidase inhibitory activity of the aglycone hesperetin and its glycosylated forms (hesperidin and G-hesperidin) and their effects on the plasma lipid profile and the oxidative-antioxidative system (TBARS and antioxidant enzymes) in rats. The concentrations of the major conjugated metabolites in rat plasma after oral administration of these compounds were also determined. Wistar male rats were randomly assigned to three groups (n=6) supplemented for 30 days with 1 mmol/kg body mass of hesperetin, hesperidin or G-hesperidin. Hesperetin was a stronger xanthine oxidase inhibitor (IC50=53 µM and Ki=17.3 µM) than the glycosylate derivatives. Supplementation with the three compounds led to a lower (more favorable) atherogenic index, and an antioxidant preventive effect from the increase of hepatic superoxide dismutase was observed associated to HT supplementation, possibly because of the higher level of hesperetin-glucuronide in rat plasma.

Enzymatic de-glycosylation of rutin improves its antioxidant and antiproliferative activities.

Bioavailability and biological properties of flavonoid glycosides can be improved after the enzymatic hydrolysis of specific glycosyl groups. In this study, we evaluate the antioxidant and antiproliferative potential of rutin after enzymatic hydrolysis performed by α-l-rhamnosidases (hesperidinase from Penicillium sp. and naringinase from Penicillium decumbens) previously heated at 70°C for 30 min to inactivate the undesirable ß-d-glucosidase activity. The highest in vitro antioxidant activity determined by DPPH radical scavenging was achieved with rutin hydrolyzed by hesperidinase. Rutin was predominantly bioconverted into quercetin-3-glucoside. There was no statistical difference between xanthine oxidase inhibition by rutin before and after hydrolysis. However, in vitro inhibitory activity against ten human tumor cell lines showed that hydrolyzed rutin exerted a more potent antiproliferative effect than quercetin and rutin on various cancer cell lines, specially glioma, and ovarian and breast adenocarcinomas. These results indicate that quercetin-3-glucoside could be a promising functional derivative obtained by rutin hydrolysis.

Optimized enzymatic synthesis of hesperidin fatty acid esters in a two-phase system containing ionic liquid.

Response surface methodology (RSM) based on a five-level, three-variable central composite design (CCD) was employed for modeling and optimizing the conversion yield of the enzymatic acylation of hesperidin with decanoic acid using immobilized Candida antarctica lipase B (CALB) in a two-phase system containing [bmim]BF(4). The three variables studied (molar ratio of hesperidin to decanoic acid, [bmim]BF(4)/acetone ratio and lipase concentration) significantly affected the conversion yield of acylated hesperidin derivative. Verification experiments confirmed the validity of the predicted model. The lipase showed higher conversion degree in a two-phase system using [bmim]BF(4) and acetone compared to that in pure acetone. Under the optimal reaction conditions carried out in a single-step biocatalytic process when the water content was kept lower than 200 ppm, the maximum acylation yield was 53.6%.