Three new metabolites from the endophytic fungus Climacocystis montana isolated from the root bark of Paeonia ostia

Two new pyridine derivatives climacomontaninates A–B (1–2), and a new sesquiterpenoid derivative climacomontanetate (3), together with twelve known compounds (4–15) were isolated from the culture extract of the fungal strain Climacocystis montana from the root bark of Paeonia ostii. The structures of these compounds were determined through spectroscopic methods such as NMR and HRMS. Moreover, we expound the absolute configuration of 1 using the organic synthesis method. The cytotoxicity against five human cancer cell lines of new compounds were evaluated by SRB assay.