Chemical Identification of Fusicoccins from a Japanese Isolate Niigata 2 of Peach Fusicoccum Canker Fungus (Phomopsis amygdali) and Production of 3′-Deacetylfusicoccin A by the Fungus

Novel diterpene glucosides Fusicoccins (FCs) isolated from the phytopathogenic fungus Phomopsis (Fusicoccum) amygdali Del. in Italy are not only potent plant growth-stimulants1, 2) but also novel plant plasma-membrane H+-ATPase activators. 3) We have found that FCs had strong seed germination-promoting activity of parasitic weeds, witchweed (Striga hermonthica (Del. ) Benth) and clover broomrape (Orobanche minor Smith). 4) We examined the peach Fusicoccum canker fungus Niigata 2 as a new fusicoccin-producing microbe, which was isolated in Niigata Prefecture of Japan and was classified as Phomopsis amygdali. 5) This report deals with chemical identification of FCs in its shaking cultures and production of 3'-deacetyl-FC A by this fungus (Fig. 1). The fungus was reciprocally shake-cultured for trial at 25℃ in 500-ml Sakaguchi flasks, each containing 100 ml of a Pharmamedia-peptone medium (5% glucose, 1% Pharmamedia, 0.5% peptone and 0.5% sodium chloride) experientially suitable for production of fusicoccin6) and its related compound cotylenin. 7) The 4-day culture filtrate (ca. 7 liters) was adjusted to pH 9.0 with aq. 5% Na2CO3, and extracted twice with EtOAc. The EtOAc extract (258 mg) was subjected to flash chromatography, using an FC-40 silica gel column (Wako, 20 cm × 2 cm I.D.) and mixtures of CHCl3/EtOH as the eluent.