Flavonoids and their glycosides are abundant in many plant-based foods. The (de)glycosylation of flavonoids by retaining glycoside hydrolases has recently attracted much interest in basic and applied research, including the possibility of altering the glycosylation pattern of flavonoids. Research in this area is driven by significant differences in physicochemical, organoleptic, and bioactive properties between flavonoid aglycones and their glycosylated counterparts. While many flavonoid glycosides are present in nature at low levels, some occur in substantial quantities, making them readily available low-cost glycosyl donors for transglycosylations. Retaining glycosidases can be used to synthesize natural and novel glycosides, which serve as standards for bioactivity experiments and analyses, using flavonoid glycosides as glycosyl donors. Engineered glycosidases also prove valuable for the synthesis of flavonoid glycosides using chemically synthesized activated glycosyl donors. This review outlines the bioactivities of flavonoids and their glycosides and highlights the applications of retaining glycosidases in the context of flavonoid glycosides, acting as substrates, products, or glycosyl donors in deglycosylation or transglycosylation reactions.

• Keywords
• Glucosidase, Glycoside hydrolase, Glycosyl donor, Glycosynthase, Hydrolysis, Rutinosidase, Transglycosylation,
• MeSH
• Flavonoids * chemistry   MeSH
• Glycoside Hydrolases * metabolism   MeSH
• Glycosides chemistry   MeSH
• Glycosylation MeSH
• Catalysis MeSH
• Publication type
• Journal Article MeSH
• Review MeSH
• Names of Substances
• Flavonoids * MeSH
• Glycoside Hydrolases * MeSH
• Glycosides MeSH

Aging is a complex physiological process that can be accelerated by chemical (high blood glucose levels) or physical (solar exposure) factors. It is accompanied by the accumulation of altered molecules in the human body. The accumulation of oxidatively modified and glycated proteins is associated with inflammation and the progression of chronic diseases (aging). The use of antiglycating agents is one of the recent approaches in the preventive strategy of aging and natural compounds seem to be promising candidates. Our study focused on the anti-aging effect of the flavonoid hesperetin, its glycoside hesperidin and its carbohydrate moieties rutinose and rhamnose on young and physiologically aged normal human dermal fibroblasts (NHDFs). The anti-aging activity of the test compounds was evaluated by measuring matrix metalloproteinases (MMPs) and inflammatory interleukins by ELISA. The modulation of elastase, hyaluronidase, and collagenase activity by the tested substances was evaluated spectrophotometrically by tube tests. Rutinose and rhamnose inhibited the activity of pure elastase, hyaluronidase, and collagenase. Hesperidin and hesperetin inhibited elastase and hyaluronidase activity. In skin aging models, MMP-1 and MMP-2 levels were reduced after application of all tested substances. Collagen I production was increased after the application of rhamnose and rutinose.

• Keywords
• hesperetin, hesperidin, normal human dermal fibroblast, rhamnose, rutinose, skin aging,
• MeSH
• Hesperidin * pharmacology   MeSH
• Hyaluronoglucosaminidase MeSH
• Collagenases metabolism   MeSH
• Humans MeSH
• Pancreatic Elastase MeSH
• Rhamnose * pharmacology   MeSH
• Skin Aging * drug effects   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• hesperetin MeSH Browser
• Hesperidin * MeSH
• Hyaluronoglucosaminidase MeSH
• Collagenases MeSH
• Pancreatic Elastase MeSH
• Rhamnose * MeSH
• rutinose MeSH Browser

The glycosidases within GH5-23 cleave the glycosidic bond of β-glucosylated or rutinosylated flavonoids. Moreover, by virtue of their transglycosylation activity, glycoconjugates with glucosyl and rutinosyl moieties are accessible. Here we report the biochemical characterization and biotechnological assessment of two heterologously expressed members of GH5-23-McGlc from Mucor circinelloides and PcGlc from Penicillium chrysogenum. Both enzymes exhibited the highest hydrolytic activities with quercetin-3-β-O-glucopyranoside, whereas lower specificity constants were determined with the rutinosides narcissin, rutin and hesperidin. High stabilities against thermal, ethanol and dimethyl sulfoxide-induced inactivation, a very limited secondary hydrolysis of the formed transglycosylation products, and no detectable product inhibition were additional features appropriate for biotechnological applications. The enzymes were compared in their efficiencies to hydrolyze rutin and to synthesize 2-phenylethyl rutinoside under homogeneous and heterogeneous reaction conditions using high rutin concentrations of 100 and 300 mM. Highest transglycosylation efficiencies were achieved with fully dissolved rutin in reaction mixtures containing 25% dimethyl sulfoxide. Molecular docking and multiple sequence alignments suggest that the hydrophobic environment of aromatic residues within the + 1 subsite of GH5-23 glycosidases is very important for the binding of flavonoid glucosides and rutinosides.

• Keywords
• Dimethyl sulfoxide, Enzyme stability, Flavonoid glycoside, Process optimization, Solubility, Transglycosylation,
• Publication type
• Journal Article MeSH

Rutinosidases (α-l-rhamnopyranosyl-(1-6)-β-d-glucopyranosidases, EC 3.2.1.168, CAZy GH5) are diglycosidases that cleave the glycosidic bond between the disaccharide rutinose and the respective aglycone. Similar to many retaining glycosidases, rutinosidases can also transfer the rutinosyl moiety onto acceptors with a free -OH group (so-called transglycosylation). The recombinant rutinosidase from Aspergillus niger (AnRut) is selectively produced in Pichia pastoris. It can catalyze transglycosylation reactions as an unpurified preparation directly from cultivation. This enzyme exhibits catalytic activity towards two substrates; in addition to rutinosidase activity, it also exhibits β-d-glucopyranosidase activity. As a result, new compounds are formed by β-glucosylation or rutinosylation of acceptors such as alcohols or strong inorganic nucleophiles (NaN3). Transglycosylation products with aliphatic aglycones are resistant towards cleavage by rutinosidase, therefore, their side hydrolysis does not occur, allowing higher transglycosylation yields. Fourteen compounds were synthesized by glucosylation or rutinosylation of selected acceptors. The products were isolated and structurally characterized. Interactions between the transglycosylation products and the recombinant AnRut were analyzed by molecular modeling. We revealed the role of a substrate tunnel in the structure of AnRut, which explained the unusual catalytic properties of this glycosidase and its specific transglycosylation potential. AnRut is attractive for biosynthetic applications, especially for the use of inexpensive substrates (rutin and isoquercitrin).

• Keywords
• azide, glycosylation, molecular modeling, rutinosidase, tunnel,
• MeSH
• Aspergillus niger enzymology   MeSH
• Disaccharides chemistry   metabolism   MeSH
• Fungal Proteins chemistry   metabolism   MeSH
• Glycoside Hydrolases chemistry   metabolism   MeSH
• Glycosylation MeSH
• Hydrolysis MeSH
• Catalytic Domain MeSH
• Recombinant Proteins metabolism   MeSH
• Rutin chemistry   metabolism   MeSH
• Molecular Docking Simulation MeSH
• Substrate Specificity MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Disaccharides MeSH
• Fungal Proteins MeSH
• Glycoside Hydrolases MeSH
• Recombinant Proteins MeSH
• Rutin MeSH
• rutinose MeSH Browser

Biotransformation has accompanied mankind since the Neolithic community, when people settled down and began to engage in agriculture [...].

• MeSH
• Bacteria enzymology   MeSH
• Biocatalysis * MeSH
• Biosensing Techniques MeSH
• Biotransformation MeSH
• Glycomics MeSH
• Fungi enzymology   MeSH
• Humans MeSH
• Agriculture MeSH
• Check Tag
• Humans MeSH
• Publication type
• Introductory Journal Article MeSH
• Editorial MeSH