[reaction: see text] An unusually bridged epidithiodiketopiperazine, pretrichodermamide A (3), was isolated from the fungus Trichoderma sp. BCC 5926. During the extensive effort to crystallize 3 for X-ray crystallographic analysis, conversion of this compound to trichodermamide A with coproduction of S(8) occurred.

Vertihemipterin A, the ascochlorin glycoside, and its aglycone, 4',5'-dihydro-4'hydroxyascochlorin, were isolated from the insect pathogenic fungus Verticillium hemipterigenum BCC 2370. A new analog, 8'-hydroxyascochlorin, and five known compounds,

A new preussomerin isomer, 3'-O-demethylpreussomerin I, five known preussomerins E - I, and two known deoxypreussomerins, deoxypreussomerin A and bipendensin (palmarumycin C11), were isolated from a lichenicolous fungus Microsphaeropsis sp. BCC 3050. These structures were elucidated by spectroscopic methods, especially 1D- and 2D-NMR. The preussomerins were evaluated for their antimycobacterial and antiplasmodial activities as well as cytotoxicity against KB, BC-1 and vero cell lines.

The known phenanthrenone trigonostemone (1), along with a new phenanthrenone, 9-O-demethyltrigonostemone (2), and two new phenanthropolones, 3,6,9-trimethoxyphenanthropolone (3) and 4,6,9-trimethoxyphenanthropolone (4), were isolated from the roots of Strophioblachia fimbricalyx. Compound 2 showed cytotoxicity against NCI-H187, KB, and MCF7 cancer cells with IC50 values of 0.8, 0.8, and 2.9 microg/mL, respectively, while 3 and 4 showed reduced cytotoxicity. Compounds 2 and 3 displayed antiplasmodial activity in vitro (IC50 values of 2.7 and 3.2 microg/mL, respectively) against Plasmodium falciparum (K1, resistant strain). In addition, the antioxidant activity of 1-4 toward DPPH radicals was determined, but only compound 2 showed any discernible activity.

Eight new compounds, fimbricalyxs B-D (1-3), fimbricalyxanhydrides A and B (4, 5), and fimbricalyxlactones A-C (6-8), together with three known compounds, trigonostemone (9), 3,6,9-trimethoxyphenanthropolone (10), and fimbricalyx A (11), were isolated from the roots of Strophioblachia fimbricalyx. The structures of the new compounds were elucidated on the basis of their spectroscopic data and, in the case of compounds 2, 4, and 7, confirmed by single-crystal X-ray crystallographic analysis. Compounds 1-4 and 8 were evaluated for their cytotoxicity (KB, MCF7, and NCI-H187 cancer cells) and antiplasmodial activity (Plasmodium falciparum, K1 multidrug-resistant strain). Fimbricalyx B (1) exhibited potent antiplasmodial activity with an IC50 value of 0.019 μM, while 4 was cytotoxic toward NCI-H187 cancer cells and showed antiplasmodial activities with IC50 values of 5.7 and 3.9 μM, respectively. In addition, the X-ray structure of 10 and the antiplasmodial activity of 11 are reported herein for the first time.

No abstract

Three new compounds, ferruginenes A (1) and B (2) and a mixture of C-5'(R) and C-5'(S) ferruginene C (3) diastereomers, have been isolated from a cytotoxic chloroform-soluble fraction of the leaves of Rhododendron ferrugineum together with 12 known compounds. The structures of these new compounds were elucidated by analyses of NMR spectroscopic and mass spectrometric data. Compounds 1-3 were tested for their cytotoxicity against three human cancer cell lines, namely, HL-60, HeLa-S3, and MCF-7.

In the courses of our search for bioactive natural products on TRAIL resistance-overcoming activity, the active EtOAc extract from the bark of Celtis tetrandra was chemically investigated. The fractionation of the extract resulted in the isolation of flavanols; (+)-afzelechin (1), (-)-epiafzelechin (2), (-)-catechin (3), and two new flavanol dimers; (-)-epiafzelechin-(4α8)-(-)-catechin (4) and (-)-epiafzelechin-(4α 8)-(-)-epicatechin (5). All isolated compounds 1-5 were tested for their TRAIL resistance-overcoming activity against AGS cells at the concentrations from 5-20 µM. It is likely that the flavanol dimers 4 and 5 exhibited weak activity in the range of the concentration of 10-20 µM as compared with the standard.