New Pyranone Derivatives and Sesquiterpenoid Isolated from the Endophytic Fungus Xylaria sp. Z184.

The fungus Xylaria sp. Z184, harvested from the leaves of Fallopia convolvulus (L.) Á. Löve, has been isolated for the first time. Chemical investigation on the methanol extract of the culture broth of the titles strain led to the discovery of three new pyranone derivatives, called fallopiaxylaresters A-C (1-3), and a new bisabolane-type sesquiterpenoid, named fallopiaxylarol A (4), along with the first complete set of spectroscopic data for the previously reported pestalotiopyrone M (5). Known pyranone derivatives (6-11), sesquiterpenoids (12-14), isocoumarin derivatives (15-17), and an aromatic allenic ether (18) were also co-isolated in this study. All new structures were elucidated by the interpretation of HRESIMS, 1D, 2D NMR spectroscopy, and quantum chemical computation approach. The in vitro antimicrobial, anti-inflammatory, and α-glucosidase-inhibitory activities of the selected compounds and the crude extract were evaluated. The extract was shown to inhibit nitric oxide (NO) production induced by lipopolysaccharide (LPS) in murine RAW264.7 macrophage cells, with an inhibition rate of 77.28 ± 0.82% at a concentration of 50 µg/mL. The compounds 5, 7, and 8 displayed weak antibacterial activity against Staphylococcus areus subsp. aureus at a concentration of 100 µM.

P and Se Binary Vacancies and Heterostructures Modulated MoP/MoSe2 Electrocatalysts for Improving Hydrogen Evolution and Coupling Electricity Generation.

It is not enough to develop an ideal hydrogen evolution reaction (HER) electrocatalysts by single strategy. Here, the HER performances are significantly improved by the combined strategies of P and Se binary vacancies and heterostructure engineering, which is rarely explored and remain unclear. As a result, the overpotentials of MoP/MoSe2 -H heterostructures rich in P and Se binary vacancies are 47 and 110 mV at 10 mA cm-2 in 1 m KOH and 0.5 m H2 SO4 electrolytes, respectively. Especially, in 1 m KOH, the overpotential of MoP/MoSe2 -H is very close to commercial Pt/C at the beginning and even better than Pt/C when current density is over 70 mA cm-2 . The strong interactions between MoSe2 and MoP facilitate electrons transfer from P to Se. Thus, MoP/MoSe2 -H possesses more electrochemically active sites and faster charge transfer capability, which are all in favor of high HER activities. Additionally, Zn-H2 O battery with MoP/MoSe2 -H as cathode is fabricated for simultaneous generation of hydrogen and electricity, which displays the maximum power density of up to 28.1 mW cm-2 and stable discharging performance for 125 h. Overall, this work validates a vigorous strategy and provides guidance for the development of efficient HER electrocatalysts.

Phosphorus vacancies improve the hydrogen evolution of MoP electrocatalysts.

Although molybdenum phosphide (MoP) has attracted increasing attention as an electrocatalyst in the hydrogen evolution reaction (HER), it is still worth exploring an effective approach to further improve the HER activities of MoP. To date, the generation and effect of P vacancies (Pv) on MoP have been rarely investigated for the HER in both alkaline and acidic media and remain unclear. Here, MoP rich in P vacancies (MoP-Pv) was prepared by hydrogen reduction to improve the HER catalytic performances. As a result, the overpotentials of MoP-Pv were 70 mV and 62 mV lower than those of pristine MoP in 1 M KOH and 0.5 M H2SO4 electrolytes, respectively. What's more, the TOFs of MoP-Pv were 3.14 s-1 and 1.19 s-1 at an overpotential of 200 mV in 1 M KOH and 0.5 M H2SO4, respectively, which are 4.1-fold and 2.5-fold higher than those of pristine MoP. Even when compared with other corresponding catalysts, the TOFs of MoP-Pv still ranked at the top. Due to the surface P vacancies, MoP-Pv possesses more electrochemically active sites and faster charge transfer capability, which all favor higher HER catalytic activities. Overall, our work validates a straightforward and vigorous strategy for improving the intrinsic HER catalytic activities of P vacancies, and also provides guidance for the development of vacancy engineering in electrocatalysts.

Acorenone C: A New Spiro-Sesquiterpene from a Mangrove-Associated Fungus, Pseudofusicoccum sp. J003.

Mangrove-derived endophytes are rich in bioactive secondary metabolites with a variety of biological activities. Recently, a fungus Pseudofusicoccum sp. J003 was first isolated by our research group from mangrove species Sonneratia apetala Buch.-Ham. The subsequent chemical investigation of the methanol extract of the culture broth of this strain has led to the isolation of a new sesquiterpenoid named acorenone C (1), two alkaloids (2-3), four phenolic compounds (4-7), and four steroid derivatives (8-11). The new structure of 1 was established by extensive spectroscopic analysis, including 1D, 2D NMR spectroscopy, and HRESIMS. Its absolute configuration was elucidated by experimental ECD and ECD calculation. The in vitro AChE inhibitory, anti-inflammatory, and cytotoxic activities of the selected compounds were evaluated. The results showed that compound 1 showed mild AChE inhibitory activity, with an inhibition rate of 23.34% at the concentration of 50 µM. Compound 9 exerted a significant inhibitory effect against nitric oxide (NO) production in LPS-stimulated RAW 264.7 mouse macrophages, with an inhibition rate of 72.89% at the concentration of 25 µM, better than that of positive control L-NMMA. Compound 9 also displayed obvious inhibition effects on the growth of two human tumor cell lines, HL-60 and SW480 (inhibition rates 98.68 ± 0.97% and 60.40 ± 4.51%, respectively). The antimicrobial activities of the compounds (1-11) against Escherichia coli, Bacillus subtilis, Staphylococcus aureus, and Pseudomonas aeruginosa were also tested; however, none of them showed antimicrobial activities.