Tetrahydroxanthone Dimers and Heterodimers

Xanthofulvin (1004) was first isolated by Masubuchi and co-workers from a Eupenicillium strain and found to be a chitin synthase II inhibitor (/C50 = 2.2 pM). Kimura and co-workers reported the isolation of SM-216289 or xanthofulvin (1004, Fig. 13.22) in addition to the known tautomer, vinaxanthone (991, (Fig. 13.21), from cultures of Penicillium sp. SPF-3059 (660). The authors demonstrated that xanthofulvin (1004) (Fig. 13.22) is also a semaphorin inhibitor (see vinaxanthmie, above) Sema3A was inhibited at a low concentration level (JCso = 0.16 pM). 

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