Zhao_2023_J.Agric.Food.Chem__

The culture of Psathyrella candolleana in host Dioscorea opposite medium 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 1 and 7 were determined by single-crystal X-ray crystallography. The semisolid culture led to four structure types of the guanacastane diterpenoid. Compound 5 showed antifungal activity against phytopathogen Fusarium incarnatum with a minimum inhibitory concentration (MIC) of 8 microg/mL, while compound 4 showed significant antifungal activity against Alternaria sp. with an MIC of 2 microg/mL. Compounds 1 and 8 also showed antifeedant activities against the silkworms with the feeding deterrence indices of 50%, at the concentrations of 50 microg/cm(2). Compound 1 showed significant cytotoxicity with IC(50) at 10.87 +/- 0.24-15.96 +/- 0.30 microM and anti-acetylcholinesterase activity with IC(50) at 37.3 microM. Also, compound 1 remarkably induced apoptosis of HL-60 at 10, 20 microM in a concentration-dependent manner. The spiral ring of 1 was vital in cytotoxicity and anti-acetylcholinesterase activity. The different media fermented by P. candolleana resulted in the chemical diversity of bioactive guanacastane diterpenoids and potential applications in the agricultural and food functions.