Abstract: We found a penicillium sp J-9 which can transform Momordica grosvenori into products A,B and C.Three products were identified by melting point,MS,IR,NMR.The method of HPLC for the transformation products A 、B and C.ZW＆A C₁₈ (250×4.60 mm,5 μm)column was used as the stationry phase.The mobile phase was acetonitrile:water,the UV detection wavelength was 203 nm,the column temperature was 30 ℃,the flow rate was 1.0 mL/min,the injection volume was 10 μL.The transformation last 120 h under 28 ℃，220r/min and substrate at a concertration of 0.5%.The three kinds of products had changeable contents in different time.Results show that the content of products A and B indicates a good linearity under these conditions with average recoveries of （99.3±1.12）% and（97.8±1.68）% and RSDs of 1.9% and 1.2%.

Key words: HPLC, microbial transformation, mogrosides, transformation products A,B and C