Crinipellins A and I, Two Diterpenoids from the Basidiomycete Fungus , as Potential Natural Fungicides.

In the course of screening for microbes with antifungal activity, we found that the culture filtrate of the IUM00035 isolate exhibited strong antifungal activity against and . Based on the phylogenetic analysis with the ITS region, the IUM00035 isolate was identified as . To identify antifungal compounds from the IUM00035 isolate, the culture filtrate of the isolate was partitioned with ethyl acetate and -butanol and, consequently, two active compounds were isolated from the ethyl acetate extract. The chemical structures of the isolated compounds were determined as crinipellin A () and a new crinipellin derivative, crinipellin I (), by NMR spectral analyses and a comparison of their NMR and MS data with those reported in the literature. Crinipellin A () exhibited a wide range of antifungal activity in vitro against , , , and (MICs = 1, 8, 31, and 31 µg/mL, respectively). Furthermore, when plants were treated with crinipellin A () (500 µg/mL) prior to inoculation with fungal pathogens, crinipellin A () exhibited disease control values of 88%, 65%, and 60% compared with non-treatment control against tomato late blight, pepper anthracnose, and wheat leaf rust, respectively. In contrast to crinipellin A (), crinipellin I () showed weak or no activity (MICs > 250 µg/mL). Taken together, our results show that the IUM00035 isolate suppresses the development of plant fungal diseases, in part through the production of crinipellin A ().