We reported that 6 species of endophytic fungi were obtained from the young stems of the tea plant Camellia sinensis (L.) O.K. (Theaceae). And it was found that one filamentous fungus Diaporthe sp., which is closely related to D. phaseolorum var. sojae, has a capacity to transform catechins possessing 2R-phenyl substitution into the corresponding 3,4-cis-dihydroxyflavan derivatives. 1,2) In this paper, we deal with the chemical structure elucidation of the two metabolites produced by another Diaporthe sp. filamentous fungus from the tea plant.We conducted rDNA analysis for the 18S and ITS1-5.8S-ITS2 regions and comparison with those of Diaporthe phaseolorum var. sojae, analyzed by us, 2) for 18S and ITS1-5.8S-ITS2 regions, and those of D. phaseolorum strain sw-93-13 (AF001018)3) for ITS1-5.8S-ITS2 region. The results showed that the similarity for the 18S region is 98.2% with D. phaseolorum var. sojae, and the similarities for the ITS1, 5.8S and ITS2 regions are 87.8%, 100% and 98.7% respectively (the total similarity is 94.4%) with D. phaseolorum strain sw-93-13 as shown in Table 1. These findings indicated that the fungus (AB245447) may be a species closely related to Diaporthe phaseolorum strain sw-93-13.
4)The endophytic filamentous fungus Diaporthe sp. was cultivated in potato dextrose broth (PDB) with rotary shaking at 90 rpm at 27°C. After the cultivation for 2 weeks, the whole culture medium including the fungus bodies was extracted with EtOAc. The evaporated extract was separated by Sephadex LH-20 (eluted with EtOH) and Sep-Pak C18 (eluted with aq. THF) to afford a yellowish metabolite (1, 47.0 mg/l) and a reddish metabolite (2, 10.3 mg/l), which were also yielded by the cultivation of the fungus on potato dextrose agar (PDA).The yellowish metabolite (1), named (ϩ)-epicytoskyrin, showed a quasi-molecular ion peak at m/z 575 to be C 30 H 23 O 12 in the FAB-MS. The IR spectrum exhibited the absorptions due to hydroxyl, carbonyl and aromatic functions and the UV spectrum showed the characteristic absorption pattern of anthraquinone derivatives. The complete decoupled 13 C-NMR of 1 showed totally fifteen carbon signals, which is only half the number of the molecular formula determined by the high-resolution FAB-MS. Therefore, it has been found that 1 is a bis-type compound.The 13 C distortionless enhancement by polarization transfer (DEPT) spectrum revealed the presence of fourteen quaternary carbons, ten tertiary carbons, two methoxyl carbons, and four carbonyl carbons. And four aromatic protons (6-and 6Ј-H, 8-and 8Ј-H), six methoxyl protons (7-and 7Ј-OCH 3 ), six methine protons (1-and 1Ј-H, 2-and 2Ј-H, 3-and 3Ј-H) and six hydroxyl protons (2-and 2Ј-OH, 4-and 4Ј-OH, 5-and 5Ј-OH) were observed in the 1 H-NMR spectrum in THF-d 6 .These physicochemical data were similar to those for cytoskyrin A (3), which is a bisanthraquinone metabolite produced by the endophytic fungus Cytospora sp. from Conocarpus erectra, 5) except for the 1 H-and 13 C-NMR signals (in THF-d 6 ) at 1,1Ј-, 2,2Ј-and 3,3Ј-positions (Table 2...