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

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 Stachybotrys chartarum 3.5365. Substrate scope investigation revealed that both of the enzymes possessed the ability to oxidize ß-OH to ketone specifically, and exhibited substrate promiscuity and high stereo-selectivity for efficiently catalyzing the structurally different prochiral ketones to chiral alcohols. These findings not only suggest that ScSDR1 and ScSDR2 might be potent synthetic tools in drug research and development, but also provide good examples for further engineered enzymes with higher efficiency and stereo-selectivity.

Enzymatic synthesis of anhydroicaritin, baohuoside and icariin.

Anhydroicaritin (1a), baohuoside (1b) and icariin (1c) were recognized as major pharmacologically active ingredients of Epimedium plants. Their primary means of acquisition were chemical isolation from plants. However, it suffers from low yield, environmental pollution and shortage of plants. Herein, to remedy these problems, biosynthesis was explored to obtain the three active ingredients. Fortunately, with SfFPT as 8-prenyltransferase, EpPF3RT and Ep7GT as glycosyltransferases, kaempferide (1) was transferred to 1a, 1b and 1c enzymatically. Thus, we report the details of this method. This approach represents a promising environmental friendly alternative for the production of these compounds from an abundant analogue.

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

Peridecalins C and D (1 and 2), one decalin and one oxygen-decalin containing polyketide-amino acid hybrids with 5/6/6 ring system, was isolated from a genetic mutant of Periconia sp. F-31. Their structures were elucidated through extensive spectroscopic data analysis, including 1 D/2D NMR and HR-MS spectra. Biosynthetically, two proposed Diels-Alder reactions are supposed to be involved in the skeleton construction of 1 and 2.

Sesquiterpenes from the endophytic fungus Periconia sp. F-31.

One new eremophilane sesquiterpene periconianone L (1), together with four known guaiane-type sesquiterpenes 4,10,11-trihydroxyguaiane (2), (-)-guai-1(10)-ene-4α,11-diolhydroxymecuration (3), guaidiol A (4), and epi-guaidiol A (5) were isolated from the endophytic fungus Periconia sp. F-31. The structure of the new compound was established by spectroscopic methods, including UV, IR, HRESIMS, and extensive NMR techniques. Compound 3 was isolated as natural product for the first time.

Biosynthesis of polyketides by two type III polyketide synthases from Aloe barbadensis.

Various bioactive polyketides have been found in Aloe barbadensis. However, the polyketide synthases (PKSs), which participate in biosynthesis of polyketides in A. barbadensis remain unknown. In this study, two type III PKSs (AbPKS1 and AbPKS2) were identified from A. barbadensis. AbPKS1 and AbPKS2 were able to utilize malonyl-CoA to yield heptaketides (TW93a and aloesone) and octaketides (SEK4 and SEK4b), respectively. AbPKS1 also exhibited catalytic promiscuity in recognizing CoA thioesters of aromatics to produce unusual polyketides. What Is more, a whole cell biocatalysis system with the capability of producing 26.4 mg/L of SEK4/SEK4b and 2.1 mg/L of aloesone was successfully established.

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

Bistachybotrysin K (1), one new phenylspirodrimane dimer with a central 6/7 oxygen heterocycle core, was isolated from the fungus Stachybotrys chartarum CGMCC 3.5365. Its structure was elucidated by extensive spectroscopic data and single-crystal X-ray diffraction. Compound 1 showed significant cytotoxicity against human tumor cell lines HCT116, NCI-H460, BGC823, Daoy, and HepG2 with IC50 values in the range of 1.1-4.7 µM.

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

Three new phenylspirodrimanes derivatives named stachybotrysins H and I (1 and 2) and stachybotrin E (3), together with one known compound stachybotrylactam (4), were isolated from Stachybotrys chartarum CGMCC 3.5365. Their structures were determined by extensive NMR data and mass spectroscopic analysis. Compounds 1 and 2 showed inhibitory effect towards potassium channel Kv1.3 with IC50 values of 13.4 and 10.9 µM, respectively.

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. Herein, we have developed a new glucuronide synthesis method using plant uridine diphosphate-dependent glucuronosyltransferases (UGTs), UGT88D4, UGT88D7, and EpGT8, enabling the convenient preparation for corresponding O-glucuronide metabolites (1a, 2a, 3a, and 3b) in milligram scale of two neurological active agents, IMM-H004 (1) and FLZ (2). Their structures were characterized by spectroscopic data analyses.

Lanostane triterpenoids and ergostane-type steroids from the cultured mycelia of Ganoderma capense.

Two new lanostane triterpenoids (1 and 2), two new ergostane-type steroids (3 and 4) together with two known lanostane triterpenoids (5 and 6) and one known steroid (7) were isolated from the cultured mycelia of Ganoderma capense (CGMCC 5.71). Their structures were determined on the basis of extensive spectroscopic (HRESIMS, 1D NMR, 2D NMR) data analyses. Compound 1 exhibited moderate cytotoxic activity against the human cancer cell line NCI-H1650 with an IC50 value of 22.3 µM, and 7 displayed cytotoxic activity against the human cancer cell line HCT116 with an IC50 value of 17.4 µM. In addition, compounds 2, 3, 5, and 6 displayed weak anti-HIV activity with IC50 values of 23.5, 46.7, 21.6, and 30.1 µM, respectively.

Four new monoterpenoids from an endophytic fungus Periconia sp. F-31.

Five monoterpenoids were isolated from the endophytic fungus Periconia sp. F-31, including three new carene-type monoterpenoids, 2-carene-5,8-diol (1), 2-carene-8,10-diol (2), 2-carene-8-acetamide (3), one new menthene-type monoterpenoid 8-hydroxy-1,7-expoxy-2-menthene (4), and one known monoterpenoid anethofuran (5). The structures of all compounds were elucidated based on a comprehensive spectroscopic data analysis, electronic circular dichroism (ECD), and calculated ECD.

Bioactive steroids and sorbicillinoids isolated from the endophytic fungus Trichoderma sp. Xy24.

A new steroid glucoside (1), along with nine known steroids (2-10) and four known sorbicillinoids (11-14), were isolated from the endophytic fungus Trichoderma sp. Xy24. Their structures were elucidated on the basis of spectroscopic data analyses and by comparison with reported data. Compounds 3, 5-7, 9, 10, and 13 exhibited significant inhibitory effects on HIV-1 virus with IC50 values ranging 1.9-9.3 µM; compounds 10, 13, and 14 showed potent inhibitory activity on LPS-induced NO production in BV2 microglia cells with inhibitory rates of 108.2, 100, and 75.1% at 10 µM, respectively. In addition, compound 10 displayed moderate cytotoxicity against BCG823 and HePG2 cell lines with IC50 values of 11.1 and 17.7 µM, respectively.

Neural anti-inflammatory sesquiterpenoids from the endophytic fungus Trichoderma sp. Xy24.

Three new sesquiterpenoids trichoacorenols B-C and cyclonerodiol B (1-3), along with three known ones (4-6), were isolated from the mangrove plant endophytic fungus Trichoderma sp. Xy24 using various column chromatography techniques. The structures of these compounds were determined on the basis of extensive spectroscopic data analyses. Compounds 1, 2, 4, and 5 were four acorane sesquiterpenes, 3 and 6 were two monocyclic sesquiterpenediols. Compounds 3 and 5 exhibited significant neural anti-inflammatory activity by inhibiting LPS-induced NO production in BV2 cells with the inhibitory rates of 75.0% and 39.2% at 0.1 µM, respectively, which are more potent than curcumin, a positive control with the inhibitory rate of 21.1% at 0.1 µM.

Flavonoids from the cultured cells of Glycyrrhiza uralensis.

Two new flavonoids (1 and 2), along with 14 known ones (3-16), were isolated from the cultured cells of Glycyrrhiza uralensis. Most of them were prenylated flavonoids. Their structures were elucidated on the basis of spectroscopic data analysis. All compounds showed non-cytotoxicity against five human tumor cell lines. The results suggest that plant cultured cells can yield the secondary metabolites that have not been found in parent plant.

[A new lactone derivative from plant endophytic fungus Periconia sp. F-31].

To investigate the secondary metabolites of endophytic fungi Pericinia sp. F-31. Column chromatography on silica gel, Sephadex LH-20 and semi-preparative HPLC were used to separate and purify the compounds. Two compounds were isolated from the fermentation broth of Periconia sp. Their structures were identified as 5-(1-hydroxyhexyl) -6-methyl-2H-pyran-2-one (1) and 2-(3-hydroxy-4-methylphenyl) -propanoic acid (2). Compound 1 was a new lactone compound, compound 2 was new natural product, and the NMR data of compound 2 was reported for the first time.

[Isolation and Sequence Analysis of the Xa21 Gene Wxon II Homologus from Different Species of Wild Rice in Yunnan.].

The Xa21 gene previously cloned from the wild rice species Oryzae longistaminata confers broad-spectrum resistance to rice leaf blight caused by different strains of Xanthomonas oryzae pv. oryzae. Here we attempted to determine the existence of Xa21 homologs in other wild rice species and rice cultivars and the sequence differences between the homologs. We synthesized specific primers based on the reported Xa21 sequence to amplify homologs of the gene exon II from several rice cultivars and three wild rice species in Yunnan Province, China. The fragments cloned from various types of O. rufipogon Griff from Jinghong and Yuanjiang, Yunnan Province, were highly homologous to the reported Xa21 gene exon II. However, the fragment was not found in O. officinalis Wall. and O. meyeriana Baill. Sequence analysis suggested that differences in nucleotides were located randomly in the fragments we cloned.