New Glycosylated Dihydrochalcones Obtained by Biotransformation of 2'-Hydroxy-2-methylchalcone in Cultures of Entomopathogenic Filamentous Fungi.

Agnieszka Krawczyk-Łebek,Edyta Kostrzewa-Susłow,Tomasz Janeczko,Monika Dymarska

doi:10.3390/ijms22179619

Agnieszka Krawczyk-Łebek, Edyta Kostrzewa-Susłow + Show 2 more

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https://doi.org/10.3390/ijms22179619

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Abstract

Flavonoids, including chalcones, are more stable and bioavailable in the form of glycosylated and methylated derivatives. The combined chemical and biotechnological methods can be applied to obtain such compounds. In the present study, 2′-hydroxy-2-methylchalcone was synthesized and biotransformed in the cultures of entomopathogenic filamentous fungi Beauveria bassiana KCH J1.5, Isaria fumosorosea KCH J2 and Isaria farinosa KCH J2.6, which have been known for their extensive enzymatic system and ability to perform glycosylation of flavonoids. As a result, five new glycosylated dihydrochalcones were obtained. Biotransformation of 2′-hydroxy-2-methylchalcone by B. bassiana KCH J1.5 resulted in four glycosylated dihydrochalcones: 2′-hydroxy-2-methyldihydrochalcone 3′-O-β-d-(4″-O-methyl)-glucopyranoside, 2′,3-dihydroxy-2-methyldihydrochalcone 3′-O-β-d-(4″-O-methyl)-glucopyranoside, 2′-hydroxy-2-hydroxymethyldihydrochalcone 3′-O-β-d-(4″-O-methyl)-glucopyranoside, and 2′,4-dihydroxy-2-methyldihydrochalcone 3′-O-β-d-(4″-O-methyl)-glucopyranoside. In the culture of I. fumosorosea KCH J2 only one product was formed—3-hydroxy-2-methyldihydrochalcone 2′-O-β-d-(4″-O-methyl)-glucopyranoside. Biotransformation performed by I. farinosa KCH J2.6 resulted in the formation of two products: 2′-hydroxy-2-methyldihydrochalcone 3′-O-β-d-(4″-O-methyl)-glucopyranoside and 2′,3-dihydroxy-2-methyldihydrochalcone 3′-O-β-d-(4″-O-methyl)-glucopyranoside. The structures of all obtained products were established based on the NMR spectroscopy. All products mentioned above may be used in further studies as potentially bioactive compounds with improved stability and bioavailability. These compounds can be considered as flavor enhancers and potential sweeteners.

Highlights

The widespread and well-documented evidence of health-promoting properties of dietary flavonoids results in a significant increase of interest in their application as dietary supplements and medicaments [1,2,3].Chalcones are one of the subclasses of dietary flavonoids, which consist of two aromatic rings joined by a three-carbon α, β-unsaturated carbonyl system
We showed results of the glycosylation of 20 -hydroxy-50 -methylchalcone
To the best of our knowledge, the attachment of the 400 -O-methyl-glucosyl moiety at C-30 observed in the cultures B. bassiana KCH J1.5 and I. farinosa KCH J2.6 has not been described in the literature yet and is related to the specific regioselectivity of entomopathogenic filamentous fungi enzymes involved in this reaction

Summary

Introduction

Chalcones are one of the subclasses of dietary flavonoids, which consist of two aromatic rings joined by a three-carbon α, β-unsaturated carbonyl system. Their mostly described biological activities can be highlighted as antifungal, antivirus, anti-diabetic, anti-inflammatory, and antitumor [1,4,5,6]. The poor aqueous solubility of flavonoid aglycones limits their oral bioavailability and, as a consequence, pharmacological application To overcome this obstacle, many attempts have been made, such as shifting the site of the absorption from the large intestine to the small intestine, increasing metabolic stability and aqueous solubility, inventing novel formulations for topical delivery [7,8]. Flavonoids with methyl moiety have improved metabolic stability, intestinal absorption and bioavailability [9,10]

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