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A new naphthoquinone, 6-hydroxy-7-methoxy-2- O-methylduniol (1), was isolated from the tubers of Sinningia hatschbachii Chautems (Gesneriaceae), together with 10 known compounds: 7-hydroxy-α-dunnione, 7-hydroxy-6-methoxy-α-dunnione, 2,4,4’,6-tetramethoxydihydrochalcone, 4’-hydroxy-2,4,6-trimethoxydihydrochalcone, 4’,2-dihydroxy-4,6-dimethoxydihydrochalcone, methyl 1-hydroxy-4-methoxy-2-naphthoate, methyl 1,4-dimethoxy-2-naphthoate, methyl 4-hydroxybenzoate, calceolarioside B, and conandroside. All compounds were identified by spectroscopic techniques, and comparison with literature. Extracts in hexane, CH2Cl2, EtOAc and EtOH were evaluated for antimicrobial activity against Staphylococcus aureus, S. epidermidis, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, C. dubliniensis, C. glabrata, and C. parapsilosis. All extracts were inactive.

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