New citrinin derivatives isolated from Penicillium citrinum

Three new coupling compounds derived from citrinin (9) and 2,3,4-trimethyl-5,7-dihydroxy2,3-dihydrobenzofuran (8) - penicitrinone A (1), penicitrinol A (2) and penicitrinone B (3) - and a new citrinin derivative - decarboxydihydrocitrinin (4) - were isolated along with 3-methoxy-1-methyl-4(1H)-quinolone (5), quinolactacin A2 (6), dihydrocitrinone (7), 2,3,4-trimethyl-5,7-dihydroxy-2,3-dihydrobenzofuran (8), citrinin (9), quinocitrinin A or B (10), and decarboxydihydrocitrinone (11) from the extract of Penicillium citrinum IFM 53298. The relative structures of compounds 1-4 were confirmed on the basis of spectroscopic investigations and chemical correlations. Citrinin (9) and quinolactacin A2 (6) both showed antifungal activity.