Bioactive saponins from Swartzia schomburgkii from the suriname rainforest.

Bioassay-guided fractionation of the MeOH extract of Swartzia schomburgkii using the engineered yeast strains 1138, 1140, and 1353 as the bioassay tool resulted in the isolation of five active (2, 4-7) and three inactive (1, 3, 8) saponins. Saponins 4 and 6 are previously unreported. The structures of all of the saponins were established based on 1D and 2D NMR spectral analysis, on acid and alkaline hydrolysis followed by TLC and GC-MS, and by comparison with literature data for known compounds. Three of the isolated compounds (4-6) showed weak cytotoxicity against the M-109 cell line.

Isolation and structure elucidation of new PKCalpha inhibitors from Pinus flexilis.

Bioassay-guided fractionation of the CH2Cl2-MeOH extract of Pinus flexilis using an assay for protein kinase C (PKC) inhibitory activity led to the isolation of the two new bioactive diarylheptanoids (3R)-1,7-bis(3, 4-dihydroxyphenyl)-3-(beta-D-glucopyranosyl)heptan-3-ol (1) and its aglycon (3R)-1,7-bis(3,4-dihydroxyphenyl)heptan-3-ol (2), together with the three known bioactive compounds, hirsutenone (3), oregonin (4), and hirsutanonol (5). The IC50 values of compounds 1-5 in the PKC assay were 1.4, 1.6, 1.4, 8.6, and 4.6 microg/mL, respectively.

Phenylethanoid glycosides from Digitalis purpurea and Penstemon linarioides with PKCalpha-inhibitory activity.

In a continuation of our search for potential tumor inhibitors from plants, it was found that the CH2Cl2-MeOH (1:1) extracts from Digitalis purpurea and Penstemon linarioides both showed PKCalpha-inhibitory bioactivity. Bioassay-directed fractionation of the extract from D. purpurea yielded the new, weakly active phenylethanoid glycoside 2-(3-hydroxy-4-methoxy-phenyl)-ethyl-O-(alpha-L-rhamnosyl)-(1-->3) -O- (alpha-L-rhamnosyl)-(1-->6)-4-O-E-feruloyl-beta-D-glucopy ran oside (1) together with the four known compounds calceolarioside A (2), calceolarioside B (3), forsythiaside (4), and plantainoside D (5). The extract from P. linarioides yielded the three known glycosides leucosceptoside A (6), acteoside (7), and poliumoside (8), together with the iridoid plantarenaloside (9). All of the isolated compounds, except compound 9, showed inhibitory activity against PKCalpha with IC50 values (in microM) of 125 (1), 0.6 (2), 4.6 (3), 1.9 (4), 14.8 (5), 19.0 (6), 9.3 (7), and 24.4 (8).

DNA-damaging steroidal alkaloids from Eclipta alba from the suriname rainforest1.

Bioassay-guided fractionation of the MeOH extract of Eclipta alba using three yeast strains (1138, 1140, and 1353) resulted in the isolation of eight bioactive steroidal alkaloids (1-8), six of which are reported for the first time from nature. The major alkaloid was identified as (20S)(25S)-22,26-imino-cholesta-5,22(N)-dien-3beta-ol (verazine, 3), while the new alkaloids were identified as 20-epi-3-dehydroxy-3-oxo-5,6-dihydro-4,5-dehydroverazine (1), ecliptalbine [(20R)-20-pyridyl-cholesta-5-ene-3beta,23-diol] (4), (20R)-4beta-hydroxyverazine (5), 4beta-hydroxyverazine (6), (20R)-25beta-hydroxyverazine (7), and 25beta-hydroxyverazine (8). Ecliptalbine (4), in which the 22,26-imino ring of verazine was replaced by a 3-hydroxypyridine moiety, had comparable bioactivity to verazine in these assays, while a second alkaloid (8) showed good activity against Candida albicans. All the alkaloids showed weak cytotoxicity against the M-109 cell line.

Enhanced yield of shiitake by saccharide amendment of the synthetic substrate.

Three experiments were performed to determine the effect of selected saccharides on mushroom yield and basidiome size of shiitake (Lentinula edodes) when grown on a synthetic substrate. Substrate formulations of sawdust, wheat bran, and millet were nonamended or amended with sucrose, fructose, or glucose. Addition of sucrose (0.6 to 1.2% [dry weight]) to the substrate stimulated mushroom yield by 11 to 20% or more. Addition of fructose at 1.2% and glucose at 0.6% resulted in similar yield increases. Most of the yield increase occurred on the first break. The substrate amended with 1.2% sucrose tended to have a more synchronous maturation for the second break resulting in fewer days when mushrooms were harvested.