目的 利用梅林青霉（Penicillium melinii AS3.4474）对熊果酸进行微生物转化研究。方法 将熊果酸投入梅林青霉液体培养基中，28 ℃、140 r/min条件下共培养5 d后，利用多种色谱学方法分离纯化转化产物，核磁共振波谱学技术进行结构鉴定。结果 熊果酸在梅林青霉液体培养基中发生了生物转化反应，分离出3个主要转化产物，依次鉴定为3-羰基熊果酸、28-O-β-D-吡喃葡萄糖熊果酸酯和3-O-β-D-吡喃葡萄糖熊果酸酯。结论 首次利用梅林青霉对熊果酸进行微生物转化并获得糖苷化和羰基化的转化产物，为熊果酸的衍生物研究奠定了基础。

Objective To study the microbial transformation of ursolic acid using Penicillium melinii. Methods Ursolic acid was put into the fluid medium inoculated with fungius (P. melinii AS3.4774) and cultured in the shaker at 28 ℃ and 140 r/min for 5 d. The crude extract was separated by chromatography. The structures of transformed products were elucidated based on the extentive NMR studies. Results Ursolic acid was transformed by P. melinii AS3.4774 and three major derivatives were isolated and elucidated. They were 3-carbonyl ursolic acid, ursolic acid-28-O-β-D-glucopyranosyl ester, and ursolic acid-3-O-β-D-glucopyranoside. Conclusion It is the first time that the three major derivatives could be microbial synthesized from ursolic acid by P. melinii AS3.4774.