Lasiodipline G and other diketopiperazine metabolites produced by Lasiodiplodia chiangraiensis

Lasiodiplodia fungi are known to colonize plants as both pathogens and/or endophytes; hence, they can be exploited for their beneficial roles. Many compound classes from the genus have exhibited their potential biotechnological applications. Herein, we report two new metabolites 1 and 2 together with three known cyclo-(D-Ala-D-Trp) (3), indole-3-carboxylic acid (4) and a cyclic pentapeptide clavatustide B (5), isolated from the submerged cultures of a recently described species L. chiangraiensis. Chemical structures of the isolated compounds were determined by extensive NMR spectroscopic analyses together with HRESIMS. The absolute configurations of the new compounds were established based on comparing experimental and calculated time-dependent density functional theory circular dichroism (TDDFT-ECD) spectra. Compound 1 exhibited significant cytotoxic activities against an array of cell lines with IC50 values of 2.9-12.6 mu M, as well as moderate antibacterial effects.

Automated summary

In this study, two new metabolites (1 and 2) and three known compounds were isolated from the submerged cultures of L. chiangraiensis. The chemical structures of the isolated compounds were determined using NMR spectroscopic analyses and HRESIMS, and the absolute configurations of the new compounds were established using TDDFT-ECD spectra. Compound 1 showed significant cytotoxic activities against various cell lines and moderate antibacterial effects.