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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 β-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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Chalcone synthases (CHSs) of the type III polyketide synthases (PKSs), catalyze the formation of a tetraketide intermediate from a CoA-tethered starter and malonyl-CoA but use different cyclization mechanisms to produce distinct chemical scaffolds. Herein, we characterized CHS and CHS-like enzymes (designated MpCHS and MpCHSL1, 2 and 3) from Marchantia paleacea and determined the crystal structure of MpCHSL1. MpCHS catalyzed a Claisen condensation to form chalcone, while MpCHSLs catalyzed the formation of lactonized α-pyrones in vitro. Based on the structural, mutational and in vitro biochemical analyses, we established that MpCHSL1 is structurally and functionally closer to prototype CHS than stilbene synthase, and characterized the structural basis for the functional diversity of the type III PKSs. A chalcone-forming mutant of MpCHSL1 was build directed by the structural information. These findings pave the way for future studies to elucidate the functional diversity of type III PKSs in liverwort. [ABSTRACT FROM AUTHOR]