Five new 5,6-seco-tremulane sesquiterpenoids from the basidiomycete Conocybe siliginea

Psathrosterols C-E, highly conjugated ergosterol derivatives from Psathyrella rogueiana with anti-inflammatory and immunosuppressive activity

Three new ergosterols featuring with a highly conjugated ring system, psathrosterols C-E (1-3), have been isolated from the fungus Psathyrella rogueiana. The structures with the absolute configurations were elucidated by means of spectroscopic methods and single crystal X-ray diffraction. Compounds 1-3 exhibit inhibitory activity against NO production with IC50 values ranging from 8.4 to 21.8 μM. Compound 1 inhibits the LPS-induced proliferation of B lymphocyte cells with an IC50 value of 12.3 μM.

Antifeedant and antiphytopathogenic metabolites from co-culture of endophyte Irpex lacteus, phytopathogen Nigrospora oryzae, and entomopathogen Beauveria bassiana

Five new tremulane sesquiterpenoids were isolated from co-culture of endophyte Irpex lacteus, phytopathogen Nigrospora oryzae, and entomopathogen Beauveria bassiana. All compounds showed obvious antifeedant activities against silkworm with inhibition percentages of 73-99%, at concentrations of 50 μg/cm². Compound 11 indicated notable antifeedant activity with inhibition percentage of 93% at concentration of 6.25 μg/cm² among them. Compounds 2, 3, 4, 8, 9, 15 and 16 indicated anti-fungal activities against I. lacteus with MIC values ≤8 μg/mL, compounds 11, 12, 16-18 showed significant anti-fungal activity against N. oryzae with MICs ≤ 4 μg/mL, and compounds 2, 5, 12 and 18 indicated significant anti-fungal activity against B. bassiana with MICs ≤ 8 μg/mL. In addition, the I. lacteus should unite B. bassiana to inhibit the production of phytotoxins from N. oryzae in the ternary culture.

Conosiligins A-D, Ring-Rearranged Tremulane Sesquiterpenoids from Conocybe siliginea

Conosiligins A-D (1-4), four ring-rearranged sesquiterpenoids, were isolated from cultures of the basidiomycete Conocybe siliginea. Their structures and absolute configurations were determined by detailed spectroscopic analyses and equivalent circulating density (ECD) calculations. Compounds 1 and 2 possess a 5/8-fused ring system, while 3 has a 5/6-fused backbone conjugated with a γ-lactone. Compound 4 is a 5,6-seco tremulane derivative with the loss of a skeletal carbon, featuring a tetracyclic system involving a pyranone moiety. Compounds 3 and 4 inhibited Con A-induced T cell proliferation with IC₅₀ values of 12.3 and 6.6 μM, respectively.

Sesquiterpenoids from Cultures of the Basidiomycetes Irpex lacteus

Eight previously undescribed sesquiterpenoids, tremutins A-H (1-8), together with three known ones (9-11), were isolated from cultures of the basidiomycetes Irpex lacteus. Structures of the new compounds together with absolute configurations were elucidated on the basis of extensive spectroscopic methods, as well as single-crystal X-ray diffractions and equivalent circulating density calculations. Compounds 1 and 2 possess an unusual 6/7-fused ring system that might be derived from a tremulane framework. Compounds 3-7 and 9-11 are tremulane sesquiterpenoids of which 4 and 5 are the first tremulane examples with a 1,2-epoxy moiety to be reported. Compounds 6, 7, 10, and 11 possess weak activities to several human cancer cell lines. Compound 8 shows a weak inhibitory effect on NO production with a half maximal inhibitory concentration (IC₅₀) value of 22.7 μM. Compound 1 inhibits the lipopolysaccharide (LPS)-induced proliferation of B lymphocyte cells with an IC₅₀ value of 22.4 μM, while 2 inhibits concanavalin A (Con A)-induced T cell proliferation and LPS-induced B lymphocyte cell proliferation with IC₅₀ values of 16.7 and 13.6 μM, respectively.

The Cocultured Nigrospora oryzae and Collectotrichum gloeosporioides, Irpex lacteus, and the Plant Host Dendrobium officinale Bidirectionally Regulate the Production of Phytotoxins by Anti-phytopathogenic Metabolites

The distinctive nature of the endophyte Irpex lacteus, host plant, and the phytopathogen Collectotrichum gloeosporioides resulted in both negative and positive regulation of the production of phytotoxins from Nigrospora oryzae. The coculture of nonhomologous I. lacteus and N. oryzae resulted in a greater number of anti-phytopathogenic metabolites from the dominant endophyte than the coculture of homologous I. lacteus and N. oryzae. The coculture of the phytopathogen N. oryzae and either the nonhomologous (isolation of I. lacteus and N. oryzae from the different plants) or homologous (isolation of I. lacteus and N. oryzae from the same plant) endophyte I. lacteus from different sources indicated that the nonhomologous I. lacteus grew faster than the homologous I. lacteus, and the production of phytotoxic azaphilone from the phytopathogenic N. oryzae decreased due to the inhibition resulting from being cocultured with nonhomologous I. lacteus. On the other hand, the production of phytotoxic azaphilone was promoted by the coculture of two phytopathogens, N. oryzae and C. gloeosporioides. The extract of the host plant, Dendrobium officinale, also increased anti-phytopathogenic metabolite production. Six new phytotoxic azaphilones from N. oryzae, four new tremulane sesquiterpenes from I. lacteus, and a new polyketone were isolated. The endophyte-phytopathogen, phytopathogen-phytopathogen, and endophyte-phytopathogen-host interactions can induce the chemical diversity of novel anti-phytopathogenic metabolites.

Total synthesis of terpenes via palladium-catalysed cyclization strategy

Nature's synthetic plans to construct molecules have been developed over millions of years of evolution and frequently prove to be among the most sophisticated. Mimicking nature's route can be a direct and feasible way for synthetic organic chemists to construct complicated molecules. However, lacking nature's ability to manipulate enzymes often prevents us from reproducing the same route. Modifying nature's approaches can provide a simpler synthetic alternative to access complex structural target molecules. Here we report a strategy that simplifies the synthesis of terpenes by inverting the order of nature's two-phase biosynthesis route. We first unite simple molecules into a polyfunctionalized linear polyenyne, with all the desired carbons and oxygens in the targeted places. This compound then undergoes polyenyne cycloisomerization, in the presence of all the functional groups, to give polyoxidized terpenes. The key reaction is a palladium-catalysed polyenyne cycloisomerization that not only tolerates the presence of all of the oxygen functionalities, but also is facilitated by them.

Two highly oxygenated Ergosterols from cultures of the Basidiomycete Conocybe siliginea

Two highly oxygenated ergosterols, (22E,24R)-3β,5α,6β,9α,14α,25-hexhydroxyergosta-7,22-diene (1), and (22E,24R)-3β,5α,6β,14α,25-pentahydroxyergosta-7,9(11),22-triene (2), together with two known ones, have been isolated from cultures of the basidiomycete Conocybe siliginea. Their structures were elucidated on the basis of extensive spectroscopic means. Two new compounds (1 and 2) were tested for their nitric oxide synthase inhibitory activities. However, none of them showed any activity (IC₅₀ > 40 μM).

Seco-tremulane Sesquiterpenoids from the Cultures of the Medicinal Fungus Irpex lacteus HFG1102

Six previously undescribed 5,6-seco-tremulane analogues, together with two known ones, were isolated from the culture broth of the medicinal fungus Irpex lacteus HFG1102. The structures of the new compounds were elucidated via extensive spectroscopic methods, including NMR and HRMS spectroscopic analyses.

Secondary metabolites from Colletotrichum capsici, an endophytic fungus derived from Siegesbeckia pubescens Makino

A rare new tremulane sesquiterpenoid analogue, 11,12-epoxy-5,6-seco-1,6(13)-tremuladien-5,12-olide (1), together with five known altenuene derivatives (2-6) was isolated from the cultures of Colletotrichum capsici, which was isolated as an endophytic fungus from fresh leaves of Siegesbeckia pubescens Makino (Compositae). Their structures were elucidated by means of spectroscopic methods and comparison with literature data. All compounds isolated were reported for the first time from the fungus C. capsici.

Three new sesquiterpenoids from cultures of the basidiomycete Conocybe siliginea

Three new sesquiterpenoids (1-3), along with four known compounds (4-7), were isolated from cultures of the fungus Conocybe siliginea. The structures of new compounds were elucidated using spectroscopic methods. The known compounds were identified by comparing their spectroscopic data with those reported in the literature. All new compounds were evaluated for cytotoxicity against five human cancer cell lines, but none of them possesses significant activity (IC50>40μM).