Oridamycins A and B, anti-Saprolegnia parasitica indolosesquiterpenes isolated from Streptomyces sp. KS84.

Oridamycins A (1) and B (2) were isolated from the fermentation broth of Streptomyces sp. strain KS84 as selective anti-Saprolegnia parasitica antibiotics. Their structures were elucidated as pentacyclic indolosesquiterpenes by the combination of NMR and spectroscopic analyses.