Anhrobacilins are novel cell growth inhibitors produced by m sp. NR2%7. Their structures have been clucidoted based on va+xu NMR experbnents and acid hydrolysis.
In our screening program for microbial products with cell growth inhibitory activities, novel antibiotics named arthrobacilins A (l), B (2) and C (3) were isolated from the culture broth of Arrhrobactor sp.
NR29671. The organism was isolated from a soil sample collected at Mt. Fuji, Yamanashi Prefecture, Japan.
Arthrobacilins showed a weak inhibitory activity against HeLa cells. In this paper, we &scribe the isolation and structnral elucidation of arthrobacilins.
Strain NR2967 was cultured in 500 ml Erlcnmeycr flasks containing each 100 ml of a medium consisting of glucose 2% potato starch 296, soybean meal 2%. yeast extract OS%, NaCl 0.3%. CaC03 0.32% and Nissan Diifoam CA-l 15 0.05% (pH 7.0). Fermentation was carried out on a rotary shaker for 4 days at 27' C.
The mycelium collected by centrifugation from the harvested broth (800 ml) was extracted with EtOH (200 ml). The concentrated extract was partitioned between water (100 ml) and EtOAc (100 ml x 2). The organic layer was concentrated under reduced pressure and the residue was chromatogmphed on a silica gel column developed with CHzC12 -MeOH (10: 1). The active eluate was concentrated under reduced pressure to give a mixture of arthrobacilins. The mixture was separated by preparative reversed phase silica gel HPLC (Shiseido, Capcell Pak Cl, s-10/25,20 x 250 mm) developed with MeOH -H20 (3:l) at a flow rate of 19 ml/min. There were obtained 185 mg of 12 (retention time, 11.2 min), 115 mg of 23 (retention time, 14.9 min) and 21 mg of 34 (retention time, 20.5 min) as colorless powders.