Aphadilactones A-D, four diterpenoid dimers with DGAT inhibitory and antimalarial activities from a Meliaceae plant.

Aphadilactones A-D (1-4), four diastereoisomers possessing an unprecedented carbon skeleton, were isolated from the Meliaceae plant Aphanamixis grandifolia. Their challenging structures and absolute configurations were determined by a combination of spectroscopic data, chemical degradation, fragment synthesis, experimental CD spectra, and ECD calculations. Aphadilactone C (3) with the 5S,11S,5'S,11'S configuration showed potent and selective inhibition against the diacylglycerol O-acyltransferase-1 (DGAT-1) enzyme (IC50 = 0.46 ± 0.09 µM, selectivity index > 217) and is the strongest natural DGAT-1 inhibitor discovered to date. In addition, compounds 1-4 showed significant antimalarial activities with IC50 values of 190 ± 60, 1350 ± 150, 170 ± 10, and 120 ± 50 nM, respectively.

[Determination methods for the content of methyl salicylate-2-O-beta-D-galactopyranoside (1-4)-beta-D-glucopyranoside].

The paper is to report the establishment of three methods for determination of methyl salicylate-2-O-beta-D-galactopyranoside (1-4)-beta-D-glucopyranoside (MSG) by HPLC, UV or potentiometric titration. The results determined by the three methods turned out to be of no significant difference (P>0.05). The method was chosen according to MSG difference test demands.

Ring A-seco triterpenoids with antibacterial activity from Dysoxylum hainanense.

Five new ring A-seco triterpenoids, dysoxyhainic acids F-J (1-5), along with a known ring A-seco triterpenoid koetjapic acid (6) were isolated from the twigs and leaves of Dysoxylum hainanense. Their structures were established on the basis of extensive spectroscopic analysis. Antimicrobial activity of all the compounds against fungi and bacteria were tested. Compounds 2-4 and 6 exhibited significant antimicrobial activity against Gram-positive bacteria, and the antibacterial SAR (structure-activity relationship) was also briefly discussed.

Limonoids and Diterpenoids from Toona ciliata Roem. var. yunnanensis.

Three new limonoids (toonaciliatins N-P, 1-3)and four new pimaradiene-type diterpenoids(toonacilidins A-D, 4-7) were isolated from the leaves and twigs of Toona ciliata Roem. var. yunnanensis.Their structures were elucidated on the basis of spectroscopic methods. Toonacilidin B(5)showed moderate inhibitory activity against H. pylori-SS1 with an MIC of 50 µg/mL.

Mesendanins A-J, limonoids from the leaves and twigs of Melia toosendan.

Ten new limonoids, namely, mesendanins A-J (1-10), together with 14 known compounds, have been isolated from the leaves and twigs of Melia toosendan. Their structures were established on the basis of spectroscopic data analysis.

Sesquiterpenes and dimeric sesquiterpenoids from Sarcandra glabra.

Two new sesquiterpenes, sarcandralactones A (1) and B (2), and five new dimeric sesquiterpenoids, sarcandrolides A-E (3-7), along with 10 known compounds were isolated from the whole plants of Sarcandra glabra. Their structures were elucidated on the basis of spectroscopic analysis. Some of the new isolates exhibit significant cytotoxicities when tested against a small panel of tumor cell lines.

Occurrence of 2-Acetyl-1-pyrroline and Its Nonvolatile Precursors in Celtuce (Lactuca sativa L. var. augustana).

Lactuca sativa L. var. augustana has a basmati rice-like odor with a green note in the background. This typical odor is due to the release of 2-acetyl-1-pyrroline (2-AP) after heating, which is confirmed by volatile analysis. Recent metabolomic and genomic studies of different rice varieties highlighted that the presence of 2-AP was linked to the accumulation of γ-aminobutyraldehyde; genome-wide association studies also indicated that acyltransferases were involved. These results prompted us to analyze nonvolatile compound precursors in L. sativa L. var. augustana (celtuce) to search for compound derivatives with a 4,5-dioxohexan alkyl amine-like structure. Hypothetical synthetic compounds were prepared from a reductive amination between 4,5-dioxohexanal and glycine, alanine, aspartic acid, and glutamic acid to give 2-(2-acetylpyrrolidin-1-yl) alkanoic acid. We proved that 2-(2-acetylpyrrolidin-1-yl) propionic acid is present in L. sativa, which, when thermally treated, released 2-AP. Other 2-AP precursors occurring in this plant are discussed.

[Correlations between the characters of the mycelium vegetative growth and the formation of the fruiting body of Ganoderma luciderm].

OBJECTIVE: To select a proper Ganoderma luciderm strain for the fruiting body production. METHOD: The strains were cultivated on the agar media and in the liquid media, respectively. Then the strains were inoculated onto the solid medium made from agricultural products (such as wheat bran, corn powder, wood meal, etc.) and cultured for a certain period. RESULT: Strains, which were easier to produce polyporic tissues at the vegetative growth stage, would be more quickly to form fruiting body with high quality and yield of the spores. CONCLUSION: Appearance of the polyporic tissues at the mycelium vegetative growth stage could be used as a marker for the strain selection for the G. luciderm substituted cultivation.

Trigochinins A-C: three new daphnane-type diterpenes from Trigonostemon chinensis.

Three highly oxygenated new diterpenes, trigochinins A-C (1-3) were isolated from Trigonostemon chinensis. Their structures with the absolute configuration were determined by a spectroscopic method, X-ray crystallography, and CD analysis. This study suggested the revision of the C-6 stereochemistry of trigonothyrins A-C reported quite recently. Compound 3 showed significant inhibition against MET tyrosine kinase activity with a IC(50) value of 1.95 microM.

Trigochilides A and B, two highly modified daphnane-type diterpenoids from Trigonostemon chinensis.

Trigochilides A (1) and B (2), two highly modified daphnane-type diterpenoids with 12-carbon-containing polyketide appendages at C-16 forming a macro-lactone with C-3, were isolated from the twigs and leaves of Trigonostemon chinensis. Their structures were elucidated by spectroscopic analysis. Trigochilides A (1) showed modest cytotoxicity against two tumor cell lines.

Monoterpenoid indole alkaloids bearing an N4-Iridoid from Gelsemium elegans.

Five new alkaloids, gelseganines A-D (1-4) and humantenine N(4)-oxide (5), were isolated from the stems and leaves of Gelsemium elegans. Compounds 1-4 represent a rare class of monoterpenoid indole alkaloids that bear an N(4)-iridoid unit. The structures of 1-5 were determined by spectroscopic analysis, single-crystal X-ray diffraction, and chemical correlation, and their absolute configurations were elucidated by CD analysis. A plausible biogenetic pathway for alkaloids 1-5 was also postulated.

Two novel triterpenoids from Dysoxylum hainanense.

Two novel rearranged oleanane-type triterpenes, dysoxyhainanin A ( 1) possessing a unique 1,3- cyclo-2,3- seco A ring with a formamido-containing appendage and dysoxyhainanin B ( 2) featuring an unprecedented 1,2-dinor-3,10:9,10- bisseco skeleton, were isolated from Dysoxylum hainanense. Dysoxyhainanin A ( 1) exhibited significant antibacterial activity against Gram-positive bacteria.