NoteEndophytic fungi have been proved to be potent sources of novel bioactive compounds. [1][2][3] We recently reported the isolation of two new g-lactones, eutypellins A and B, two enteudesmane sesquiterpenes, ent-4(15)-eudesmen-11-ol-1-one and ent-4(15)-eudesmen-1a,11-diol, and three pimarane diterpenes, diaporthein B (3), 4) scopararane A (4), 5) and libertellenone C (5), 6) from the endophyte Eutypella sp. BCC 13199.7) Since the genus Eutypella has been rarely investigated with only a few other papers describing novel metabolites, 8,9) further chemical studies on this fungal strain was conducted. Fermentation of BCC 13199 using a bioreactor, instead of the previously employed static incubation in flasks, led to the production of two new pimarane-type diterpenes, eutypellones A (1) and B (2), together with the previously described compounds.7) In this paper we report the isolation and structure elucidation of 1 and 2, and cytotoxic activities of pimaranes 1-5.
Results and DiscussionEutypellone A (1) was isolated as a minor diterpene constituent of the broth extract. The molecular formula of 1 was determined to be C 20 H 30 O 4 by high resolution-electrospray ionization-mass spectra (HR-ESI-MS). The IR spectrum exhibited intense absorption bands at n max 3423 (broad) and 1721 cm Two new pimarane-type diterpenes, eutypellones A (1) and B (2), were isolated from the endophytic fungus Eutypella sp. BCC 13199. Cytotoxic activities of the pimaranes 1-5, isolated from this fungus, were evaluated.
Cordybislactone (3), a new stereoisomer of the 14-membered bislactone clonostachydiol, together with its open ring analog (4), was isolated from the hopper pathogenic fungus Cordyceps sp. BCC 49294. The relative and absolute configurations of 3 were determined by chemical derivatizations, including the modified Mosher's method. The stereochemistry of clonostachydiol was determined using the natural compound isolated from Xylaria sp. BCC 4297. The result revealed that the absolute configuration of clonostachydiol, previously determined by synthesis, should be revised to its enantiomer.
Two new drimane sesquiterpenoids, fudecadione A and fudecadione B (1, 2), together with the known brefeldin A (3) and fulvic acid (4), were isolated from the soil fungus Penicillium sp. BCC 17468. Chemical structures were determined based on spectroscopic evidence including 1D and 2D NMR and mass spectral data. The proposed relative stereochemistry of fudecadiones A and B was based upon NOESY spectral data and chemical means. Compounds 1 and 4 exhibited anticancer activity against MCF-7, KB, and NCI-H187, with IC (50) values in the range of 5.05-45.43 µg/mL, while compound 2 was inactive against these tumor cells. Brefeldin (3) also displayed antimalarial activity against PLASMODIUM FALCIPARUM (K1, multidrug-resistant strain), with an IC (50) value of 1.12 µg/mL.
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