Inhibition of chitin synthase 2 and antifungal activity of lignans from the stem bark of Lindera erythrocarpa.

Potent chitin synthase 2 inhibitors, methyllinderone (1), linderone (2) and kanakugiol (3) were isolated from the stem bark of L. erythrocarpa Makino (Lauraceae). These compounds inhibited chitin synthase 2 with IC(50) values of 23.3, 21.4 and 23.8 microg/mL, respectively. Methyllinderone (1) and linderone (2) exhibited no inhibitory activities for chitin synthases 1 and 3 from S. cerevisiae, and chitin synthase 1 from Candida albicans up to the concentration of 280 microg/mL, while kanakugiol (3) exhibited very weak activity against chitin synthase 1 of C. albicans with an IC(50) of 160 microg/mL. All of the compounds showed moderate to weak antifungal activities against various pathogenic fungi (MIC: 8 - >128 microg/mL) including Cryptococcus neoformans, Aspergillus fumigatus, and Colletotrichum lagenarium. The results indicate that these compounds are specific inhibitors of chitin synthase 2 and can potentially serve as antifungal agents.