A regio-specific 4--methyltransferase from regiospecifically catalyzing 8-prenylkeampferol to icaritin.

is widely used in traditional Chinese medicine and contains rich bioactive compounds. These compounds often have a methyl group at their 4'-OH position catalyzed by methyltransferases. Therefore, studying methyltransferases in plants is of great significance.

A Cytochrome P450 Enzyme Catalyses Oxetane Ring Formation in Paclitaxel Biosynthesis.

Oxetane synthase (TmCYP1), a novel cytochrome P450 enzyme from Taxus×media cell cultures, has been functionally characterized to efficiently catalyse the formation of the oxetane ring in tetracyclic taxoids. Transient expression of TmCYP1 in Nicotiana benthamiana using 2α,5α,7β,9α,10β,13α-hexaacetoxytaxa-4(20),11(12)-diene (1) as a substrate led to the production of a major oxetane derivative, 1β-dehydroxybaccatin IV (1 a), and a minor 4β,20-epoxide derivative, baccatin I (1 b). However, feeding the substrate decinnamoyltaxinine J (2), a 5-deacetylated derivative of 1, yielded only 5α-deacetylbaccatin I (2 b), a 4β,20-epoxide.

Unravelling and reconstructing the biosynthetic pathway of bergenin.

Bergenin, a rare C-glycoside of 4-O-methyl gallic acid with pharmacological properties of antitussive and expectorant, is widely used in clinics to treat chronic tracheitis in China. However, its low abundance in nature and structural specificity hampers the accessibility through traditional crop-based manufacturing or chemical synthesis. In the present work, we elucidate the biosynthetic pathway of bergenin in Ardisia japonica by identifying the highly regio- and/or stereoselective 2-C-glycosyltransferases and 4-O-methyltransferases.

Exploring the catalytic diversity of two short-chain dehydrogenases/reductases from .

Short-chain dehydrogenase/reductases (SDRs) belong to the NAD(P)(H)-dependent oxidoreductase superfamily, which have various functions of catalyzing oxidation/reduction reactions and have been generally used as powerful biocatalysts in the production of pharmaceuticals. In this study, ScSDR1 and ScSDR2, two new SDRs have been identified and characterized from 3.5365.

Functional Characterization and Cyclization Mechanism of a Diterpene Synthase Catalyzing the Skeleton Formation of Cephalotane-Type Diterpenoids.

CsCTS, a new diterpene synthase from Cephalotaxus sinensis responsible for forming cephalotene, the core skeleton of cephalotane-type diterpenoids with a highly rigid 6/6/5/7 tetracyclic ring system, was functionally characterized. The stepwise cyclization mechanism is proposed mainly based on structural investigation of its derailment products, and further demonstrated through isotopic labeling experiments and density functional theory calculations. Homology modeling and molecular dynamics simulation combined with site-directed mutagenesis revealed the critical amino acid residues for the unique carbocation-driven cascade cyclization mechanism of CsCTS.

Structural diversification of bioactive bibenzyls through modular co-culture leading to the discovery of a novel neuroprotective agent.

Bibenzyls, a kind of important plant polyphenols, have attracted growing attention for their broad and remarkable pharmacological activities. However, due to the low abundance in nature, uncontrollable and environmentally unfriendly chemical synthesis processes, these compounds are not readily accessible. Herein, one high-yield bibenzyl backbone-producing strain was constructed by using a highly active and substrate-promiscuous bibenzyl synthase identified from in combination with starter and extender biosynthetic enzymes.

Functional characterization of a cycloartenol synthase and four glycosyltransferases in the biosynthesis of cycloastragenol-type astragalosides from .

Astragalosides are the main active constituents of traditional Chinese medicine Huang-Qi, of which cycloastragenol-type glycosides are the most typical and major bioactive compounds. This kind of compounds exhibit various biological functions including cardiovascular protective, neuroprotective, etc. Owing to the limitations of natural sources and the difficulties encountered in chemical synthesis, re-engineering of biosynthetic machinery will offer an alternative and promising approach to producing astragalosides.

Targeting the biological activity and biosynthesis of hyperforin: a mini-review.

Hyperforin is a representative polycyclic polyprenylated acylphloroglucinols (PPAPs) that exerts a variety of pharmacological activities. The complete biosynthesis pathway of hyperforin has not been elucidated due to its complex structure and unclear genetic background of its source plants. This mini-review focuses on the bioactivity and biosynthesis of hyperforin.

Enzymatic synthesis of anhydroicaritin, baohuoside and icariin.

Anhydroicaritin (), baohuoside () and icariin () were recognized as major pharmacologically active ingredients of plants. Their primary means of acquisition were chemical isolation from plants. However, it suffers from low yield, environmental pollution and shortage of plants.

Dengratiols E-G, three bioactive pairs of enantiomeric bibenzyl dimers from Dendrobium gratiosissimum.

Three pairs of enantiomeric bibenzyl dimers, (±)-dengratiols E-G [(±)-1-3], were obtained through various chromatographic techniques including chiral HPLC, from the ethanol extract of Dendrobium gratiosissimum. Their structures were elucidated to be R-(+)-1 and S-(-)-1, R-(+)-2 and S-(-)-2, and αR, α'R-(-)-3 and αS, α'S-(+)-3 on the basis of the extensive spectroscopic data and ECD analyses, respectively. The isolated enantiomerically pure along with their racemic forms showed moderate cytotoxicity against human HCT116, U87-MG, HepG2, BGC823, and PC9 cancer cell lines (IC 9.

Radical -Adenosyl Methionine Enzyme BlsE Catalyzes a Radical-Mediated 1,2-Diol Dehydration during the Biosynthesis of Blasticidin S.

The biosynthesis of blasticidin S has drawn attention due to the participation of the radical -adenosyl methionine (SAM) enzyme BlsE. The original assignment of BlsE as a radical-mediated, redox-neutral decarboxylase is unusual because this reaction appears to serve no biosynthetic purpose and would need to be reversed by a subsequent carboxylation step. Furthermore, with the exception of BlsE, all other radical SAM decarboxylases reported to date are oxidative in nature.

Two new 5/6/6 polyketide-amino acid hybrids from a genetic mutant of sp. F-31.

Peridecalins C and D ( and ), one decalin and one oxygen-decalin containing polyketide-amino acid hybrids with 5/6/6 ring system, was isolated from a genetic mutant of sp. F-31. Their structures were elucidated through extensive spectroscopic data analysis, including 1 D/2D NMR and HR-MS spectra.

Sesquiterpenes from the endophytic fungus sp. F-31.

One new eremophilane sesquiterpene periconianone L (), together with four known guaiane-type sesquiterpenes 4,10,11-trihydroxyguaiane (), (-)-guai-1(10)-ene-4,11-diolhydroxymecuration (), guaidiol A (), and epi-guaidiol A () were isolated from the endophytic fungus sp. F-31. The structure of the new compound was established by spectroscopic methods, including UV, IR, HRESIMS, and extensive NMR techniques.

Dengratiols A-D, four new bibenzyl derivatives from Dendrobium gratiossimum.

Dengratiol A (1), an unprecedented bibenzyl derivative bearing a tropolone unit together with three pairs of bibenzyl enantiomers (±)-dengratiols B-D [(±)-2-(±)-4], were isolated from Dendrobium gratiossimum Rchb.f. The resolution of enantiomers was performed with chiral HPLC.

[Study on chemical bibenzyls in Dendrobium gratiosissimum].

Nineteen compounds were isolated and structurally characterized from an ethanol extract of Dendrobium gratiossimum, including dendrogratiol A(1), DDB-1(2), 3,4-dihydroxyl-5,3',4'-trimethoxybibenzyl(3), amoenylin(4), chrysotoxine(5), DTB(6), 3,4,4'-trihydroxyl-5,3'-dimethoxybenzyl(7), 3-methylgiga(8), aloifol(9), gigantol tetramethyl ether(10), batatasin Ⅲ(11), moscatilin(12), moniliformine(13), gigantol(14), DMB(15), flavanthrinin(16), cannithrene-2(17), 3,4-dihydroxyl-5,4'-dimethoxystilbene(18) and 4-hydroxy-3,5,4'-trimethoxystilbene(19). 1 was a new compound, and 2-10, 16, 18 and 19 were obtained from this plant species for the first time. In vitro cytotoxic and antiviral activities of these isolates were evaluated, which displayed that 4 showed moderate cytotoxicity against human hepatoma cell line HepG2 with the IC_(50) of 10.

Morusalisins A-F, six new Diels-Alder type adducts, as potential PTP1B inhibitors from cell cultures of Morus alba.

Six new Diels-Alder type adducts, morusalisins A-F (1-6), were isolated from Morus alba cell cultures. The structures of 1-6 were determined by extensive spectroscopic data analysis, including HRESIMS, NMR, and ECD experiments. Furthermore, compounds 1-6 exhibited potent protein tyrosine phosphatase 1B (PTP1B) inhibitory activity with IC values ranging from 1.

Biosynthesis of polyketides by two type III polyketide synthases from .

Various bioactive polyketides have been found in However, the polyketide synthases (PKSs), which participate in biosynthesis of polyketides in remain unknown. In this study, two type III PKSs (AbPKS1 and AbPKS2) were identified from . AbPKS1 and AbPKS2 were able to utilize malonyl-CoA to yield heptaketides (TW93a and aloesone) and octaketides (SEK4 and SEK4b), respectively.

Morusalones A-D, Diels-Alder Adducts with 6/7/6/6/6/6 Hexacyclic Ring Systems as Potential PTP1B Inhibitors from Cell Cultures of .

Morusalones A-D (-), a new class of Diels-Alder adducts featuring unprecedented 6/7/6/6/6/6 hexacyclic core skeletons with a unique bridged cycloheptenone ring, were isolated from cell cultures. The biosyntheses for - were proposed through an unusual Diels-Alder cycloaddition with quinostilbenes as dienophiles and prenyl 2-phenylbenzofuran as a diene to yield the typical methylhexene unit and a rare intramolecular nucleophilic addition to form the cycloheptenone ring. Compounds - exhibited protein tyrosine phosphatase 1B inhibitory activity.

Bistachybotrysin K, one new phenylspirodrimane dimer from with potent cytotoxic activity.

Bistachybotrysin K (), one new phenylspirodrimane dimer with a central 6/7 oxygen heterocycle core, was isolated from the fungus CGMCC 3.5365. Its structure was elucidated by extensive spectroscopic data and single-crystal X-ray diffraction.

Ep7GT, a glycosyltransferase with sugar donor flexibility from Epimedium pseudowushanense, catalyzes the 7-O-glycosylation of baohuoside.

Icariin (1a), a 7-O-glycosylated flavonoid glycoside, is recognized as the major pharmacologically active ingredient of Epimedium plants, which have been used in traditional Chinese medicine for thousands of years. However, no glycosyltransferase (GT) responsible for the 7-O-glycosylation of flavonoids has been identified from Epimedium plants to date. Herein, a GT, Ep7GT, was identified from E.

Enzymatic Synthesis of Bioactive O-Glucuronides Using Plant Glucuronosyltransferases.

Many O-glucuronides exhibiting various pharmacological activities have been found in nature and in drug metabolism. The glucuronidation of bioactive natural products or drugs to generate glucuronides with better activity and druggability is important in drug discovery and research. In this study, by using two uridine diphosphate (UDP)-dependent glucuronosyltransferases (GATs, UGT88D4 and UGT88D7) from plants, we developed two glucuronidation approaches, pure enzyme catalysis in vitro and recombinant whole-cell catalysis in vivo, to efficiently synthesize bioactive O-glucuronides by the glucuronidation of natural products.

Bistachybotrysins F-J, five new phenylspirodrimane dimers with a central cyclopentanone linkage from Stachybotrys chartarum.

Bistachybotrysins F-J (1-5), five new phenylspirodrimane dimers with a central cyclopentanone core were isolated from Stachybotrys chartarum CGMCC 3.5365. The structures of 1-5 were elucidated through extensive spectroscopic data analysis, including 1D/2D NMR, HR-MS, and ECD spectra.

Three new phenylspirodrimane derivatives with inhibitory effect towards potassium channel Kv1.3 from the fungus .

Three new phenylspirodrimanes derivatives named stachybotrysins H and I ( and ) and stachybotrin E (), together with one known compound stachybotrylactam (), were isolated from CGMCC 3.5365. Their structures were determined by extensive NMR data and mass spectroscopic analysis.

Biocatalytic access to diverse prenylflavonoids by combining a regiospecific -prenyltransferase and a stereospecific chalcone isomerase.

Prenylflavonoids are valuable natural products that have diverse biological properties, and are usually generated biologically by multiple metabolic enzymes in nature. In this study, structurally diverse prenylflavonoids were conveniently synthesized by enzymatic catalysis by combining GuILDT, a regiospecific chalcone prenyltransferase, and GuCHI, a stereospecific chalcone isomerase that has promiscuous activity for both chalcones and prenylchalcones as substrates. Our findings provided a new approach for the synthesis of natural/unnatural bioactive prenylflavonoids, including prenylchalcones and optical prenylflavanones with chalcone origins.

Enzymatic synthesis of glucuronidated metabolites of two neurological active agents using plant glucuronosyltransferases.

Glucuronidation is an important and popular metabolic reaction in vivo of drugs. The further evaluation of biological activity and toxicity of glucuronides is necessary in the course of the drug research and development. However, the synthesis of glucuronides is limited by the lack of efficient approach.