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Two endophytes from the same Ginkgo bilobahost were isolated and cultured separately. Three new eremophilane sesquiterpenoids (1–3), three new furan derivates (6, 8–9), one new polyketide (10), and four known compounds (4, 5, 7, 11) from Paraphaeosphaeriasp. and two new 10-membered macrolides (12–13), a new liner polyketide (14), a new benzofuran (15), and six known compounds (16–21) from Nigrospora oryzaewere isolated. The structures of the isolated compounds were determined by spectroscopic methods, NMR calculations, and ECD calculations. The compounds 3–7, 9–10, 12, and 14–17showed significant antiphytopathogenic effects against mycotoxigenic Alternariasp. comparable to the activity of nystatin (positive control). Compounds 2, 6, 8, 9, and 18indicated inhibitions against phytopathogen Fusarium asiaticumwith MICs < 10 μg/mL. In addition, the compounds with weak antifungal activities from two endophytes were mixed to test their antifungal activity. The results showed that the metabolites from two endophytes had synergistic antifungal effects, and the beneficial interactions between natural products can induce more antifungal effects against plant pathogens than that of single compounds.

The antagonistic coculture with tea phytopathogen Colletotrichum pseudomajusinduces antifungal cryptic metabolites from isogenesis endophyte Daldinia eschscholtziiagainst tea phytopathogens. Sixteen new polyketides with six structural frameworks including ten cryptic ones, named coldaldols A–C (1–3), collediol (5), and daldinrins A–L (10–20and 23), were found from the coculture of C. pseudomajusand D. eschscholtziiby different culture methods. The unique framework of compounds 11and 12featured a benzopyran-C7polyketone hybrid, and compounds 13–16were characterized by the novel benzopyran dimer. The structures were determined mainly by spectroscopic methods, including extensive one-dimensional (1D), two-dimensional (2D) NMR, high resolution electrospray ionisation mass spectroscopy (HRESIMS), ECD calculation, and single-crystal X-ray diffraction. The configuration of acyclic compounds 5and 18were determined by application of the universal NMR database. Most compounds showed significant antifungal activities against the tea pathogens C. pseudomajusand Alternariasp. with MICs of 1–8 μg/mL. Compound 12had stronger antifungal activity than that of positive drug nystatin. The ether bond at C-4 of the benzopyran derivative increased the antifungal activity. Compounds 4–9and 11–23showed antifeedant activities against silkworms with feeding deterrence indices of 15–100% at the concentration of 50 μg/cm2.

The culture of Psathyrella candolleanain host Dioscorea oppositemedium produced seven new guanacastane diterpenoids, psayamin (1) as an unprecedented 5/7/6/6/6/6/7/5-fused octacyclic spiro scaffold both under liquid and semisolid conditions, psathins A–C (4–6) with a 5/7/6 tricyclic backbone by liquid medium, psathins D–E (7–8) as the same unprecedented skeletons of 5/6/7/6-fused tetracyclic or 6/7/6 tricyclic structures, and psathin F (9) with a 5/7/5/6 tetracyclic backbone by semisolid medium. The structures were elucidated by detailed spectroscopic analyses and those of 1and 7were determined by single-crystal X-ray crystallography. The semisolid culture led to four structure types of the guanacastane diterpenoid. Compound 5showed antifungal activity against phytopathogen Fusarium incarnatumwith a minimum inhibitory concentration (MIC) of 8 μg/mL, while compound 4showed significant antifungal activity against Alternariasp. with an MIC of 2 μg/mL. Compounds 1and 8also showed antifeedant activities against the silkworms with the feeding deterrence indices of 50%, at the concentrations of 50 μg/cm2. Compound 1showed significant cytotoxicity with IC50at 10.87 ± 0.24–15.96 ± 0.30 μM and anti-acetylcholinesterase activity with IC50at 37.3 μM. Also, compound 1remarkably induced apoptosis of HL-60 at 10, 20 μM in a concentration-dependent manner. The spiral ring of 1was vital in cytotoxicity and anti-acetylcholinesterase activity. The different media fermented by P. candolleanaresulted in the chemical diversity of bioactive guanacastane diterpenoids and potential applications in the agricultural and food functions.

Eleven new chlorinated cyclopentene derivatives, periconsins A-K, and a new diketopiperazine, periconzin, were found from Periconia sp.cultured in three different media by the one strain many compounds strategy. Additionally, the C-1 methyl hydroxylation of chlorinated cyclopentene was found for the first time in the host plant culture. The structures were identified by extensive spectroscopic analyses, electronic circular dichroism (ECD) and 13C NMR calculations, and single-crystal X-ray diffraction. Compounds 3, 5, 7–11, 15, and 17showed significant antifungal activities against the plant pathogens Periconia sp., Altemaria sp., and Nigrospora oryzaewith MICs ≤2 μg/mL. Other compounds had antifungal activities with MICs ≤8 μg/mL. The antifungal structure–activity relationship of these metabolites indicated that the chlorine at C-5 can increase the activity, but the hydroxy group at C-1 lowered the activity.