3.4. Microbial transformation using Cunninghamella echinulate ATCC 18968

Biotransformation of papaverine using Cunninghamella echinulate ATCC 18968 produced one metabolite. The residue (800 mg) was dissolved in 30 ml of methanol/dichloromethane mixture (1:1) and adsorbed onto 800 mg Celite and dried. The adsorbed sample was placed onto a glass column (110 × 2 cm) packed with silica after making a slurry in dichloromethane. The column was gradiently eluted with dichloromethane 100% then dichloromethane: methanol (98.5:1.5, 98:2) and 10 ml fractions were collected. Fractions 40–60 were pooled together to give compound 1. Further purification was achieved using sephadex LH-20 column, as determined by TLC. The metabolite was obtained in the form of white powder (70 mg, R f 0.6 S 2).