Synthesis of umbelliferone derivatives in Escherichia coli and their biological activities

Abstract

BackgroundUmbelliferone, also known as 7-hydroxycoumarin, is a phenolic metabolite found in many familiar plants. Its derivatives have been shown to have various pharmacological and chemo-preventive effects on human health. A uridine diphosphate glycosyltransferase YjiC from Bacillus licheniformis DSM 13, a cytochrome P450BM3 (CYP450 BM3) variant namely mutant 13 (M13) from Bacillus megaterium, and an O-methyltransferase from Streptomyces avermitilis (SaOMT2) were used for modifications of umbelliferone.ResultsThree umbelliferone derivatives (esculetin, skimmin, and herniarin) were generated through enzymatic and whole cell catalysis. To improve the efficiencies of biotransformation, different media, incubation time and concentration of substrate were optimized and the production was scaled up using a 3-L fermentor. The maximum yields of esculetin, skimmin, and herniarin were 337.10 μM (67.62%), 995.43 μM (99.54%), and 37.13 μM (37.13%), respectively. The water solubility of esculetin and skimmin were 1.28-folds and 3.98-folds as high as umbelliferone, respectively, whereas herniarin was 1.89-folds less soluble than umbelliferone. Moreover, the antibacterial and anticancer activities of herniarin showed higher than umbelliferone, esculetin and skimmin.ConclusionsThis study proves that both native and engineered enzymes could be employed for the production of precious compounds via whole cell biocatalysis. We successfully produced three molecules herniarin, esculetin and skimmin in practical amounts and their antibacterial and anticancer properties were accessed. One of the newly synthesized molecules the present research suggests that the combinatorial biosynthesis of different biosynthetic enzymes could rapidly promote to a novel secondary metabolite.Electronic supplementary materialThe online version of this article (doi:10.1186/s13036-017-0056-5) contains supplementary material, which is available to authorized users.

Umbelliferone instability during an analysis involving its extraction process

“…As known from literature [ 11 , 26 ], umbelliferone can be transformed to hydroxylated (esculetin), glucosylated (skimmin), and methylated (herniarin) derivatives in the enzymatic degradation process. The presented paper shows that this compound is also chemical and thermal unstable.…”

“…The presented experiments are justified, as umbelliferone is the parent compound for many derivatives naturally occurring in plants, which suggests its structural lability [ 11 – 13 ]. Moreover, their results may be useful for food producers and consumers, as umbelliferone transformation products are likely to be formed during the preparation and processing of food products.…”

“…Umbelliferone receives the attention of scientists due to its diverse bioactivities in a number of applications in various therapeutic fields [ 9 ]. The most notable is its strong ability to absorb UV light [ 10 ], and hence its usage as an ingredient of sun protection cosmetics and as an optical brightener for textiles [ 11 – 13 ]. Like other coumarins, it also occurs in many food products.…”

Biosynthesis of fraxetin from three different substrates using engineered Escherichia coli

“…Since the metabolic pathway responsible for the synthesis of simple coumarins is well established, these compounds have been synthesized in E. coli. Scopoletin, esculetin, umbelliferone, skimming (umbelliferone 7-O-glucoside), and herniarin (7-O-methyl umbelliferone) were synthesized in E. coli [18,19]. For the fraxetin synthesis process in E. coli, two routes were postulated (Fig.…”

RadH: A Versatile Halogenase for Integration into Synthetic Pathways

“…Metabolic engineering approaches have previously been developed for the production of valuable natural plant coumarins in E. coli 19, 20, 21. However, as far as we are aware, this is the first example of the production of a “non‐natural” halogenated coumarin from glucose in E. coli .…”