AJI9561, a new cytotoxic benzoxazole derivative produced by Streptomyces sp.

(Traders) 1.0%, yeast extract 0.1%, and CaCO3 0.2% (pH 7.2). The fermentation was carried out at 28°C on a rotary shaker (180 rpm) for 96 hours. The culture broth of Streptomyces sp. AJ9561 (5 liters) was filtered to obtain mycelium, which was extracted with acetone (3 liters) at room temperature. The extract was concentrated in vacuo to an aqueous suspension, which was extracted with EtOAc (500 mix3). The organic layers were combined and dried in vacuo to give brown oil (3.5 g). The residue was subjected to a Diaion HP-20 column (150ml). After washing with 30%aqueous acetone, the column was eluted with 80% aqueous acetone. The fraction was pp.102 104